乙型肝炎病毒

乙型肝炎病毒

Updated February, 2009

Stéphanie Villet, Ph.D., David Durantel, Ph.D., Fabien Zoulim, M.D., Ph.D.

译者：辛永宁主治医师

青岛市市立医院肝病科

Email: xinyongning@163.com

钟艳丹主治医师

江苏省东南大学附属第二医院肝病科

Email：zhangyandan@sina.com

审阅者：周宝桐主治医师

北京协和医院感染科

GENERAL DESCRIPTION

概述

Virology Guided Medline Search

病毒学

Hepatitis, or inflammation of the liver, denotes an organ-specific designation for a clinical entity of widely diverse etiology and pathogenesis. Over the last 35 years, viruses belonging to at least 6 different families have been identified and linked to most hepatitis found in man (243). Hepatitis B virus (HBV) is the most common amongst those that cause chronic infections in human.

　　肝炎，即肝脏炎症，是由许多不同病因和发病机制导致的器官特异性表现的总称。在过去的35年，已发现至少属于6个不同科的病毒，绝大多数人的肝炎与它们有关(243)。其中，乙型肝炎病毒（HBV）是引起人类慢性感染最常见的一种病毒。

HBV is small and spherical, 42 nm in diameter, enveloped DNA virus and represents the prototype virus of the Hepadnaviridae family (112). Infectious virion, also termed Dane particle, contains a relaxed circular, partially double-stranded genome of approximately 3200 base pairs that is encapsidated by the core (C) protein to form the nucleocapsid. This genome consists of four overlapping open reading frame (ORF): S, for the surface, or envelope gene; C, for the core gene; X, for the X gene; and P, for the polymerase gene (Figure 1). The S and C genes have upstream regions termed pre-S (pre-S1 and pre-S2) and pre-C (Figure 1). A mutation in one viral gene often results in a mutation in an overlapping ORF, thereby restricting the number of viable mutant viruses (Figure 1). However, HBV variants do occur and their presence might alter the clinical presentation and disease course (30, 125, 254) . A copy of the viral polymerase (P) protein is covalently attached to the 5' extremity of the negative strand of DNA in the nucleocapsid. This enzyme carries several activities responsible for the priming of DNA synthesis (terminal protein), the synthesis of the first DNA strand (reverse transcriptase activity), the destruction of the RNA template (RNase H activity), and the synthesis of the second strand (DNA-dependant DNA polymerase activity). Other proteins, mainly host derived, have been found in minute amount in the nucleocapsid and are thought to be involved either in the morphogenesis of the particles or in events happening in the early stage of the infection. Surrounding the nucleocapsid is the lipid envelope that contains small (S), medium (pre-S2) and large (pre-S1) viral surface glycoproteins (HBsAg). The pre-S1 and pre-S2 represent two of the more immunogenic portions of HBsAg (147). The development of humoral and cellular response to HBsAg is protective, and recombinant HBsAg provides the basis for the HBV vaccines currently available. In addition to Dane particles, two other types of particles are found in excess in the bloodstream of HBV carriers, the spheres (22 nm) and the rods (22 nm width and variable length) particles which contain HBsAg and host-derived lipids, but no nucleic acid. These particles are noninfectious and might play a protective role by absorbing neutralizing antibody and thus hiding virions from host defenses.

　　HBV呈小球型，直径42nm，包膜DNA病毒，是嗜肝DNA病毒科中的一员(112)。感染的病毒体又名Dane颗粒，含有松弛环状部分双链基因组，约含3200个碱基对，被核心（C）蛋白包裹，形成核衣壳。基因组包括4个重叠开放读码区（ORF）：S区，对应表面或包膜基因；C区，编码核心基因； X区，编码X基因以及P区，聚合酶基因 (图1)。S基因和C基因上游区被称为前S区（前S1区和前S2区）和前C区（图1）。病毒基因突变往往导致重叠ORF的突变，从而限制了突变病毒的数量（图1）。然而，HBV变异株的出现，结果可能改变疾病的临床表现及病程（30, 125, 254）。病毒聚合酶（P）蛋白在核衣壳内以共价键与DNA负链5’端相连。该酶具有多种活性，包括启动DNA合成（末端蛋白），合成第一条DNA链（逆转录酶活性），降解RNA模板（RNase H活性），以及合成第二条链（依赖DNA的DNA聚合酶活性）。其他蛋白，主要是宿主来源蛋白，已发现在核衣壳内少量存在，被认为参与病毒颗粒的形态形成，或在早期感染阶段发挥作用。包被核衣壳的是脂质外膜，包含小分子（S），中分子（前S2）和大分子（前S1）病毒表面糖蛋白（HBsAg）。前S1蛋白和前S2蛋白是HBsAg中免疫原性较强的两个部分(147)。针对HBsAg发生的体液和细胞免疫应答具有保护性，重组HBsAg是目前HBV疫苗的基础。除了Dane颗粒外，两种其他类型的颗粒在HBV携带者的血液中也大量存在，即球型（22nm）和柱状（22nm宽，长度不定）颗粒，内含HBsAg和宿主来源的脂质，但不含核酸。这些颗粒没有感染性，可能通过吸附中和抗体起保护作用，从而使病毒颗粒逃避宿主防御反应。

Little is known about the earliest events in the viral life cycle due to the lack, until recently, of a fully infectable cell line (123). Enveloped virions bind to the cell via contact between, most likely, its pre-S proteins and one (or several) host receptor(s) (76, 122, 163, 285, 332) and enter the cell most likely by a pH-independent fusion mechanism (133, 164). After endocytic entry, a translocation mechanism allowing viral particle exit from the endosome has been recently suggested (316). Then, the virus is uncoated, and the viral genome translocated to the nucleus where it is converted to covalently closed circular DNA (ccc-DNA) most likely by host DNA polymerase (296) (Figure 2). The host RNA polymerase II uses the ccc-DNA as template for transcription (296). Four (possibly 5) different transcripts of 0.7, 2.1, 2.4, and 3.5-kb respectively, are produced from internal hepatic-specific promoters and are processed, 5 capped and 3 polyadenylated, by host machinery. The greater-than-genome-length pre-genomic (pgRNA) transcript is translated into three different products, the nucleocapsid or core protein, a secreted protein also called the "e antigen" (HBeAg) as well as the polymerase protein (P). This 3.5-kb pgRNA is also used as a template for the viral RNA-dependent DNA polymerase (P) to produce the minus DNA strand that will be subsequently used as template, by the same enzyme (DNA-dependent DNA polymerase activity of P), to produce the partially double-stranded progeny genomes (251). The reverse transcription takes place within subviral core particles (321), thereby implying that encapsidation of the genomic RNA template must represent the initial step in the genomic replication pathway. The large surface protein is produced via the 2.4-kb pre-S1 transcript, and the medium and the small surface proteins are produced via the 2.1-kb pre-S2/ S transcript. A fourth 0.7-kb transcript is translated into the X protein (HBx). The function of HBx is yet not completely elucidated, but appears to be complex (40, 244). HBx is required for mammalian Hepadenavirus infection in vivo and might function as a weak transcriptional activator and as a stimulator of cytoplasmic signal transduction pathways (40, 244, 384).

　　一直到近来完全感染细胞系出现前(123)，关于病毒生活周期的初期过程了解甚少(123)。包膜病毒颗粒与细胞粘附，最可能是通过前S蛋白与某一（或几个）宿主受体接触(76, 122, 163, 285, 332)，并通过非pH依赖的融合机制进入细胞(133, 164)。近来的研究提示，存在一种移位机制，使病毒颗粒经过胞饮作用进入细胞后能够从内含体中释放(316)。然后，病毒脱去外膜，病毒基因组转移进入细胞核内，最可能通过宿主DNA多聚酶作用，形成共价闭合环状DNA (ccc-DNA) (296) (图 2)。宿主RNA多聚酶Ⅱ利用ccc-DNA作为转录模板(296)。通过宿主机制，由肝脏特异启动子，生成0.7，2.1，2.4和3.5-kb的四种（可能五种）不同的转录产物，并进行5’端加冠和3’端多聚腺苷酸化。长度甚于全基因组的前基因组（pgRNA）转录物被翻译成3种不同的产物，核衣壳或核心蛋白，一种也可称为“e抗原”(HBeAg) 的分泌蛋白，以及多聚酶蛋白（P）。3.5-kb的pgRNA也可作为依赖病毒RNA的DNA聚合酶的模板，形成DNA负链，进而作为模板，在同种酶（依赖DNA的DNA聚合酶P活性）作用下，形成部分双链子代基因组(251)。逆转录在亚病毒核心颗粒内进行(321)，提示基因组RNA模板装配在基因复制途径中必须完成初始步骤。大分子表面蛋白由2.4-kb前S1基因转录物产生，中小分子蛋白由2.1-kb前S2/S基因转录物产生。第四种0.7-kb转录物被翻译成X蛋白（HBx）。HBx功能复杂，还不完全清楚(40, 244)。HBx对于哺乳动物体内嗜肝DNA病毒感染是必须的，可能具有弱转录活化剂，以及细胞质信号转导途径激活剂的功能(40, 244, 384)。

Viral assembly occurs at the level of intracellular membranes where viral surface glycoproteins are expressed, folded and retained. The nucleocapsid is thought to bud from the endoplasmic reticulum (ER) or an ER-derived vesicle. Virions are then transported through the secretory pathway, traversing the Golgi apparatus where their carbohydrates are processed, and released in the extracellular compartment.

　　病毒装配在胞内膜水平进行，病毒表面糖蛋白在此表达，折叠和固定。核衣壳从内质网（ER）或ER来源的囊泡出芽。然后，病毒颗粒经分泌途径运输，通过高尔基体糖基化，并释放到细胞外。

More details on the biology of the virus and the life cycle (Figure 2) can be found in several general reviews published in journals (111, 194, 251, 296) and a book (112).

　　关于病毒生物学和生活周期更详细的内容(图 2)，可以在发表在一些杂志(111, 194, 251, 296)和一本书(112)的几个综述中找到。

Epidemiology Guided Medline Search

流行病学

Incidence of Chronic Hepatitis B Worldwide

全世界慢性乙型肝炎发病率

Despite the availability of efficient vaccines (196), HBV continues to pose a serious global health problem. The world health organization (WHO) estimates that hepatitis B is the ninth leading cause of death worldwide (336). Of the 2 billion people who have been infected with HBV worldwide, more than 350 millions are chronically infected. These chronic carriers are exposed to a high risk of life-threatening progressive chronic hepatitis, liver cirrhosis and hepatocellular carcinoma (26, 218). The distribution of HBV infection varies greatly throughout the world. HBV incidence remains particularly high in developing countries of Asia, Africa, the Amazon, the Middle East, the Eastern Europe, and the Pacific Islands (5, 48, 221, 305, 323) where vaccination programs are either not available, being installed or too recently introduced to measure their impact, and where perinatal or child to child transmission is still important (18, 43, 48, 305). Infection is less common in Western Europe and North America where less than 1% of the population is infected (339). For instance, in the United States there are approximately 1.25 million HBV carriers and the number of new infections per year has declined from an average of 450,000 in the 80's to about 78,000 in 2001 (Center for Disease Control data). However, worldwide, it is estimated that more than 50 million new infections with HBV occur yearly, and as many as 1 million deaths annually can be attributed to the effects of this infection (142, 232).

　　虽然疫苗得到有效应用，但HBV仍然是一项严重的全球健康问题。世界卫生组织（WHO）估计，乙型肝炎在全世界死亡原因中，排名第九位(336)。全世界有20亿人感染HBV，超过3.5亿人呈慢性感染。慢性携带者病情进展，形成慢性肝炎，肝硬化和肝细胞癌，有危及生命的高度风险(26, 218)。HBV感染分布在全世界范围内变化很大。HBV发病率在亚洲，非洲，亚马逊河，中东，东欧和太平洋岛等发展中国家仍然明显较高，这些国家有的没有免疫接种计划，或正在建设中，或者引入很晚还没有发挥作用，而且这些国家围产期或儿童与儿童的传播依旧严重(18, 43, 48, 305)。HBV感染在西欧和北美少见，感染人口不到1%的(339)。例如，美国有大约有125万HBV携带者，每年新发感染病例数在80年代为每年450,000人，到2001年下降到大约78,000人（疾病控制中心数据）。然而，据估计全世界每年有超过5000万HBV新发感染病例，每年死于HBV感染的患者超过100万(142, 232)。

Review Article: Hoffman, C., Thio, C. Clinical Implications of HIV and Hepatitis B Co-infection in Asia and Africa. The LANCET Infectious Diseases 2007; Vol.7, Issue 6, 402-409.

Classification

分类

HBV has been divided into 8 genotypes, A through H. Genotype A is found in Western and Northern Europe as well as in Africa. Some studies suggest that it may be associated with a better response rate to IFN therapy for chronic hepatitis (155). Genotypes B and C are found in Asia. Clinical studies have suggested an association of genotype C with a more severe chronic liver disease and a poorer response rate to IFN therapy (157, 372). Genotype D is observed mainly in the Mediterranean bassin and is associated with a higher prevalence of pre-C mutants in chronically infected individuals (120) as well as a lower response rate to IFN (155). Genotype E is mainly observed in Africa, while genotype F has been identified in South-America and Polynesia. Finally, genotype H has been recently described in Amerindians from Central America.

　　HBV分为A~H 8个基因型。A基因型见于西欧、北欧及非洲。一些研究显示，A基因型慢性肝炎患者可能对IFN治疗应答率较好(155)。B和C基因型见于亚洲。临床研究提示，C基因型与更严重的慢性肝病以及对IFN治疗较差应答率有关(157, 372)。D基因型主要见于地中海流域，慢性感染患者中前C区变异率较高(120)，对IFN治疗应答率较差(155)。E基因型主要见于非洲，而F基因型已证实见于南美洲和波里尼西亚。H基因型近来已在来自中美洲的美国印第安人中发现。

Transmission

传播

HBV is present in many body fluids of infected individuals. As viral load is very high and may reach 1010 copies per ml of serum, the rate of transmission may be very high after exposure, as compared to other viruses such as HIV and HCV. The main routes of infection are perinatal transmission, blood and percutaneous transmission and sexual transmission (194).

　　HBV存在于感染患者的多种体液中。由于病毒载量非常高，在血清中可能达到10¹⁰ copies/ml，因而相比HIV和HCV等其它病毒，暴露后感染率极高。主要感染途径是围产期传播、血液和经皮肤传播以及性传播(194)。

Neonatal infections: The greatest sources of new infections worldwide have been from infected mothers to the newborn, or among very young children. About 90% of infants infected at birth or during their first year of life, and 30 to 50% of children infected between 1 to 4 years of age, develop a chronic infection. This risk of chronic infection declines to ~ 5% for older children and adults. The risk of death from HBV-related cirrhosis or liver cancer is estimated at 25% for persons who become chronically infected during childhood. The risk of vertical transmission varies depending on geographical regions. In North America, Western Europe and Africa, the risk of vertical transmission from chronically infected mothers is approximately 10%. This is expected from the low incidence of HBeAg serum positivity among carriers in these areas, indicating that the infected mothers usually have a low viral load. Furthermore, in many countries pregnant women are screened for HBV markers and newborns are vaccinated to reduce the risk of chronic infection. The high rate of chronicity in many parts of Africa is attributed to horizontal spread to young children from playmates, and adults involved in their care.

新生儿感染：全世界新发感染主要途径是感染的母亲传染给新生儿，或者幼儿间的传染。大约90%在出生时或出生后第1年发生感染的婴儿和30%~50%在1~4岁间感染的儿童，发展成慢性感染。年长的儿童和成年人慢性感染的风险下降至~5%。儿童时期慢性感染的患者死于HBV相关肝硬化或肝癌的风险估计有25%。垂直传播的风险随地理区域而异。在北美，西欧和非洲，慢性感染孕妇垂直传播的风险大约10%。因为这些区域的携带者，血清中HBeAg的阳性率较低，提示感染母亲通常病毒载量较低。此外，许多国家孕妇进行HBV标志物筛查，新生儿予以免疫接种，以减少了慢性感染的风险。非洲许多地区慢性化的率高，这是由于幼儿玩伴间以及与照顾它们的成人间的水平传播。

In Asia, the perinatal rate of transmission is as high as 90%, because most of the pregnant women who are chronically infected are HBeAg serum positive and have high titers of circulating HBV. In infants who are infected by HBV, the rate of chronicity of viral infection can reach 90% (314). Studies performed in mice suggest that HBeAg may cross the placenta during pregnancy and induce an HBV specific immune tolerance in the fetus to epitopes of the viral core protein (241). This finding was interpreted to indicate that when the newborn is exposed to HBV at birth, the risk of chronic infection becomes very high because the potential to react to a major viral antigen has been reduced. Some data from humans suggest that HBeAg may indeed cross the placenta (353), though evidence that this causes immune tolerance and facilitates chronic infection has not yet been obtained. Injection of hyper-immune globulin to HBsAg (HBIG) and vaccination of the newborns at birth can reduce the risk of chronic infection from HBeAg positive mothers by >90% (17, 213, 315).

　　在亚洲，围产期传播发生率高达90%，因为大多数慢性感染的孕妇血清HBeAg阳性，循环中HBV滴度高。感染HBV的婴儿，慢性化率达90%(314)。小鼠研究显示，HBeAg在妊娠期间可能通过胎盘，诱导胎儿对病毒核心蛋白抗原决定簇产生HBV特异性免疫耐受(241)。这一发现解释了当新生儿出生时暴露于HBV后，由于对主要病毒抗原潜在的应答减少，因而发生慢性感染的风险极高。一些人类研究数据显示，HBeAg可能确实可以通过胎盘(353)，尽管还未获得它引起免疫耐受和促进慢性感染的证据。新生儿出生时，注射针对HBsAg的高效价免疫球蛋白(HBIG)，并接种疫苗，能减少来自HBeAg阳性孕妇慢性感染的风险90%以上(17, 213, 315)。

Intra-uterine infection is thought to be uncommon and may be related to very high viremia levels in the mother. This may explain in part some of the failures of passive-active immunization at birth. Other causes of prophylaxis failure have been identified in the newborns. They include host genetic factors of non response to the vaccine (35) and the selection of surface gene mutants that may escape both HBIG and the anti-HBs response induced by the vaccine (38, 241).

　　宫内感染少见，可能与孕妇体内极高水平的病毒血症有关。这也许解释了一些新生儿出生时被动主动免疫失败的部分原因。其它已证实的在新生儿中预防失败的原因，包括对疫苗无应答的宿主遗传因素(35)，以及可能同时逃避HBIG和疫苗引起的抗HBs应答(38, 241) 的基因变异。

Blood transfusion, intravenous drug use, sexual transmission and nosocomial infections: The risk of HBV transmission by blood transfusion has decreased dramatically since the early 1970s, because of the exclusion of paid donors and the introduction of serological screening of volunteer blood donors for serum HBsAg and anti-HBc immunoglobulins. In the US, the risk of HBV transmission via blood products is now one out of 63,000 transfusions, down from 15% in the 1960s (4, 119). The current incidence may be attributed to the failure to identify infected blood donors because of the serological window during the incubation period following infection, the presence of some rare variants escaping the serologic assay for HBsAg, particularly when concurrent testing for anti-HBc is not performed, and the problem of occult HBV infections, in which neither HBsAg or anti-HBc are detected. HBV genome detection by PCR in blood donors may decrease this risk but the cost-effectiveness of this strategy remains to be evaluated.

输血，静脉吸毒，性传播以及院内感染：自20世纪70年代早期，由于禁止有偿献血，以及志愿献血员HBsAg血清学初筛和抗HBc免疫球蛋白的应用，输血引起的HBV传播已经显著减少。在美国，目前由于血制品引起HBV传播的风险已经从20世纪60年代的15%下降到在63,000例输血中仅发生1例(4, 119)。当前传播的发生率与筛选献血员失败有关，因为病毒感染后的潜伏期存在血清学窗口期，存在一些罕见变异株逃避HBsAg血清学检测，尤其未同时检测抗HBc时，以及隐匿性HBV感染问题，HBsAg或抗HBc检测均为阴性。PCR法检测献血员HBV基因，可能减少传播的风险，但该方法的成本效益仍需评估。

Percutaneous infection remains a major mode of HBV transmission, and this includes intravenous drug use, tattoos, acupuncture, ear piercing, sharing razors, etc... Sexual transmission still represents 40% of the new cases of acute hepatitis B in many developed countries (4, 119), while the role of intravenous drug use seems to be decreasing with time representing now only 6-10% of new cases. HBV can be transmitted by accidental needle stick in the healthcare setting (4, 119). The risk of nocosomial transmission is estimated to be 30% from highly viremic patients. On the other hand, transmission from healthcare worker to patient although rare, may occur occasionally as has been reported, for example, with the transmission of HBV from infected surgeons (136). Other cases of nosocomial transmission have been reported in hemodialysis centers and in the setting of organ transplantation even from donors who only have anti-HBc antibody, which when found by itself is usually a marker of a past infection from which an individual has recovered. For instance, de novo HBV infection in the liver graft recipient can be observed in more than 50% of cases when the donor has antibody to HBcAg but no other serological marker of infection, implying a transient infection at some time in the past, with survival of residual virus. Horizontal transmission can be observed among children or in institutionalized persons via close bodily contact leading to HBV infection through minor skin breaks and mucous membranes (339).

　　经皮肤感染仍然是HBV的一种主要传播方式，这包括静脉吸毒，文身，针灸，穿耳，共用剃刀等等。在许多发达国家，性传播仍占新发急性乙型肝炎病例的40% (4, 119)，而静脉吸毒的地位似乎在随时间下降，目前仅占新发病例的6-10%。在医疗机构，HBV能通过意外针刺传播(4, 119)。据估计，来自高病毒血症患者院内传播的风险为30%。另一方面，医疗机构工作人员传染给患者的现象虽然罕见，但也偶有报道，例如，来自已感染HBV的外科医生的传播(136)。其它院内传播的病例报道来自血液透析中心，以及器官移植时，即使供体仅有抗HBc抗体，单独HBc抗体阳性常常是个体既往发生感染已恢复的标志。例如，当肝移植供体有HBcAg抗体，但无其它血清学感染标志物时，这提示既往曾有感染，存在残余病毒，因而肝移植患者新发HBV感染的发病率超过50%。水平传播见于儿童之间或职业人群中，它们通过密切身体接触，经小皮肤破损和粘膜引起HBV感染(339)。

In summary, high-risk groups for HBV infection have been identified. They include healthcare workers, especially surgeons and physicians working in haemodialysis, oncology, or AIDS units; laboratory workers in contact with blood or human fluids; institutionalized handicapped persons, their attendants and family; patients requiring frequent blood product transfusions ; patients on haemodialysis; patients with organ transplantation; intravenous drug users; men who have sex with men; promiscuous heterosexuals.

　　总之，HBV感染的高危人群已明确。他们包括医疗机构的工作人员，尤其是外科医生，以及在血液透析，肿瘤或AIDS病房工作的内科医生；与血液或体液接触的实验室工作人员；护理机构的残疾人，它们的护理人员及家属；需要长期血制品治疗患者；血液透析患者；器官移植患者；静脉吸毒者；男同性恋；性乱交者。

Carroll MB, Bond MI. Use of Tumor Necrosis Factor-alpha Inhibitors in Patients with Chronic Hepatitis B Infection. Semin Arthritis Rheum 2008 Jan 24 [Epub ahead of print].

Clinical Manifestations Guided Medline Search

临床表现

HBV is a highly infectious agent and infection occurs frequently after exposure (275). The clinical course of primary infection can be acute or chronic, and the outcome is frequently age dependent (91). In adults, HBV infection is usually self-limited and resolves in less than 6 month. In two-third of adults infections are sub-clinical; only one-third of infected adults develops clinical hepatitis (236). Fulminant hepatitis occurs in less than 1% of acute infection and results in the death of patients most of the time. A small number of HBV-infected adults develop chronic hepatitis (209). In contrast, HBV infection in the first few months of life seldom causes clinical illness and almost always leads to persistent infection (236, 266).

　　HBV具有高度传染性，暴露后常发生感染(275)。初次感染后临床表现呈急性或慢性过程，临床结局通常与年龄有关(91)。成年人中，HBV感染通常是自限性的，6个月内病情好转。2/3的成人呈亚临床感染，仅1/3的成人感染发展成临床肝炎(236)。急性感染发生暴发性肝炎的不到1%，这种情况下大多数患者死亡。少数成人HBV感染发展成慢性肝炎(209)。与成人相比，在出生最初几个月内的HBV感染很少引起临床疾病，总是导致持续感染(236, 266)。

During acute symptomatic HBV infection, patients may have fever, malaise, fatigue, weakness, anorexia, abdominal discomfort, conditions that may be due to the high production of IFNs, TNF-α, and other inflammatory cytokines. When massive liver cell necrosis occurs over a short period of time, patients may also present with jaundice. The diagnosis of acute HBV infection is based on history, ALT profiles (up to 100-fold increase), and HBV antigen-antibody or/and serum HBV DNA detection. After an incubation period of 4 to 24 weeks, HBsAg can be detected in blood. HBeAg and HBV DNA occurring at the same time indicate active viral replication. Loss of HBeAg is usually associated with marked decrease in HBV DNA. Some patients seroconvert to HBeAg but remain HBV DNA positive with active liver disease. These patients have the "e" mutant variant or pre-core mutant of the virus (30, 262, 324) (Figure 1). IgM specific anti-HBcAg antibody develops early during infection and is followed by anti-HBs antibody as the patient improves. Most patients recover within 6 months of illness onset, and the ALT level return to normal.

　　急性HBV感染症状期，患者可能出现发热，不适，疲劳，虚弱，食欲减退，腹部不适，这些症状可能与IFNs，TNF-α和其它炎性细胞因子产生增加有关。当短期内大量肝细胞出现坏死时，患者也可能出现黄疸。急性HBV感染的诊断根据病史，ALT水平（可升高>100倍），以及HBV抗原-抗体或/和血清HBV DNA检测的结果。在4~24周潜伏期后，HBsAg能在血中检测到。与此同时，HBeAg和HBV DNA出现提示病毒复制活跃。HBeAg消失常伴有HBV DNA的显著下降。一些患者HBeAg发生血清转换，但仍然HBV DNA阳性并有活动性肝病。这些患者存在病毒“e”变异或前C区变异(30, 262, 324) (图1)。在感染期间，抗HBcAg特异性IgM抗体早期出现，随后抗HBs抗体出现，患者病情改善。大部分患者在发病后6个月内恢复，ALT水平恢复正常。

Persistence of HBsAg 6 months after the onset of hepatitis illness indicates that the HBV infection has become chronic. This happens in approximately 5% of adults infected (209). In wild-type HBV chronic infections, three stages characterize the progression of liver disease in immunocompetent individuals, possibly leading to advanced liver disease with cirrhosis and its complications.

　　肝炎发病后6个月，HBsAg持续阳性，提示HBV感染转为慢性。这出现在大约5%的成人感染中。HBV野生株的慢性感染，免疫功能正常者肝病进程表现为三期，可能导致进展性肝病如肝硬化及其现并发症。

The first stage, lasting from one to 15 years, is characterized by an immunotolerant state with high HBV replication levels and low-grade inflammatory lesions in the liver. Often, in the early stages of infection, infected hepatocytes do not stimulate a strong immune response, with the result that serum transaminase levels remain near normal and the liver continues to shed high titers of virus. This is especially true in the case of vertical transmission of HBV. These patients are defined serologically by HBsAg and HBeAg positivity, high HBV DNA levels (usually higher than 108 copies per ml), and strictly normal serum ALT levels. In this situation, treatment is not indicated because patients usually have no liver damage or very minimal liver disease at liver biopsy examination. The risk of disease progression is minimal so long as ALT levels remain within the normal range. Furthermore, the results of clinical trials of IFN-α, or nucleoside analogue inhibitors of the viral DNA polymerase, showed that patients with high HBV DNA load and normal ALT levels have almost no chance of undergoing HBeAg sero-conversion as a result of treatment.

　　第1期，持续1~15年，表现为免疫耐受期，HBV复制水平高，肝内炎症损害程度低。通常，在感染早期，感染肝细胞不能激活强免疫应答，结果表现为血清转氨酶水平接近正常，肝脏持续高病毒载量。这尤其发生在HBV垂直传播的患者中。这些患者定义为HBsAg和HBeAg血清学阳性，HBV DNA水平高（常>10⁸copies/ml），血清ALT水平完全正常。在该情况下，不推荐治疗，因为患者通常无肝损伤或肝活检提示肝脏病变轻微。在ALT水平维持正常期间疾病进展的风险很小。此外，IFN-α或核苷类病毒DNA多聚酶抑制剂的临床试验结果显示，HBV DNA高载量和ALT水平正常的患者经治疗后几乎不能发生HBeAg血清转换。

The second stage, lasting from a few weeks to months, is characterized by clearance of infected hepatocytes with an increase of hepatocyte necrosis and serum aminotransferase levels and decrease of serum HBV DNA level. Loss of serum HBV DNA (by non-PCR-based methods) may occur spontaneously in about 5 to 10% of patients yearly or as a result of antiviral therapy. If antiviral therapy is not carried out during this immunoactive stage, clinical symptoms may appear. If this stage persists due to the inability of the immune system to control viral infection, chronic hepatitis with cumulative liver damage may occur.

　　第2期，持续数周到数月，表现为感染肝细胞被清除，肝细胞坏死增加以及血清氨基转氨酶水平升高和HBV DNA水平下降。每年大约5~10%的患者或自发，或者通过抗病毒治疗出现HBV DNA转阴（非PCR法）。在免疫活跃期，如果不进行抗病毒治疗，可能出现临床症状。如果该期由于免疫系统不能控制病毒感染而持续，会出现慢性肝炎，肝损伤累积。

In many chronically infected patients, HBeAg sero-conversion occurs, in which HBeAg antigen becomes undetectable, and anti-HBe antibodies appear, while only low levels of viral DNA (<104 copies per ml) persist in the serum. Biological markers of hepatic function normalize. This is considered a good clinical outcome, and is indicative of immunological control of the infection in the liver. In this phase, patients are considered inactive carriers of HBV (56). In this situation, liver histology usually reveals remission of liver disease activity, and the risk of progressing liver disease is considered to be minimal so long as viral load remains low and ALT levels normal. As viral ccc-DNA persists in the liver, episodes of viral reactivation may however occur either spontaneously or as a result of immune suppression (358).

　　在许多慢性感染患者中，发生HBeAg血清转换，HBeAg抗原检测不到，抗HBe抗体出现，而HBV DNA在血清中持续低水平存在（<10⁴copies/ml)。肝功能生化学指标正常。这被视为一种好的临床结局，提示肝脏感染得到免疫控制。该期患者视为HBV非活动性携带者(56)。该情况下，肝脏组织学常提示肝病活动程度减轻，并且只要病毒持续低载量，ALT水平正常，肝病进展的风险很小。然而肝内病毒ccc-DNA持续存在，病毒可能自发或因免疫抑制而再度复制活跃(358)。

Although, the liver remains the main locus for HBV-induced diseases, some extrahepatic diseases are caused by immune complexes of hepatitis B antigens and antibodies. These include serum sickness syndrome, polyarteritis nodosa, membranoproliferative glomerulonephretis, and cryoglobulemia (194). The formation of these complexes is a consequence of active viral replication and usually begins in the early stages of an infection, particularly in children. This is the reason why treatment of HBV associated periarteritis nodosa or glomerulonephritis relies on the use of antiviral therapy. This may be combined initially with plasmapheresis and a short course of corticosteroids to decrease the consequences of the deposition of immune complexes on the artery walls (276, 333). Several studies have shown the clinical benefit of anti-HBV agents including vidarabine (adenine arabinoside), IFN-α, lamivudine, famciclovir, and adefovir (92, 171, 220, 354, 359). Indeed, the control of viral replication is accompanied by a decrease of immune complex formation and the improvement of the clinical signs of vasculitis. Clearance of HBsAg and concurrent cure of the vasculitis have been observed by several investigators. In patients presenting with a life threatening vasculitis, therapy may combine prednisone to decrease the consequences of vascular inflammation, plasmapheresis to decrease the circulating immune complexes and their consequences, and antivirals. After a few weeks, when the clinical situation is under control, prednisone and plasmapheresis can be stopped while antiviral therapy is continued until HBe or HBs sero-conversion occurs.

　　尽管肝脏是HBV致病的主要部位，但乙肝抗原抗体免疫复合物也导致一些肝外疾病，包括血清病综合征，结节性多动脉炎，膜性增殖性肾小球肾炎以及冷球蛋白血症(194)。这些免疫复合物形成是病毒活跃复制的结果，常在感染早期阶段开始，尤其在儿童中。这就是为什么HBV相关结节性多动脉炎或肾小球肾炎的治疗依赖于抗病毒治疗的应用。开始可能需要联合血浆置换，以及短期皮质激素治疗，以减少动脉壁上免疫复合物沉积(276, 333)。一些研究已经显示了阿糖腺苷，IFN-α，拉米夫定，泛昔洛韦和阿德福韦等抗HBV药物的临床益处(92, 171, 220, 354, 359)。的确，伴随病毒复制的控制，免疫复合物形成减少，血管炎临床体征改善。一些研究者发现HBsAg清除的同时血管炎也被治愈。在有危及生命的血管炎患者中，需要联合治疗，以泼尼松治疗减轻血管炎症反应的后果，用血浆置换减少循环免疫复合物造成的影响，并应用抗病毒治疗。几周后，当临床状况得到控制，可以停止强的松和血浆置换治疗，而继续抗病毒治疗，直到HBe或HBs发生血清转换。

Laboratory Diagnosis Guided Medline Search

实验室诊断

The aim of the following section is to briefly review the markers and tests used in the diagnosis of acute and chronic hepatitis B.

　　接下来的部分是对急性和慢性乙型肝炎使用的标志物和试验检查的回顾。

Serologic Diagnosis of HBV Infections: The serological markers of HBV infection vary depending on whether the infection is acute or chronic (Table 1). The first serologic marker of HBV infection is HBsAg, which can be detected from 2 to 24 weeks after contamination with HBV. The presence of HBsAg often antedates symptoms or abnormalities of hepatic biochemistry (e.g. raised ALT) by 6-8 weeks. In patients who recover, HBsAg disappears from the serum in 2-6 months, and protective anti-HBs antibody appears after a variable window period. Persistence of HBsAg beyond 6 month after the onset of the infection is widely accepted as a sign of chronic infection. Detection of HBsAg is the most widely used diagnostic test for HBV infection. An improved version of the previously developed sandwich enzyme-linked immunoabsorbent assay (ELISA), which includes microparticles as solid phase and computerized instrumentation, is currently used for the detection of HBsAg (77). These microparticle enzyme immunoassays (MEIAs) can rapidly (45 min) detect 100-200 pg of HBsAg per ml of serum, corresponding to an approximate titer of 3.107 particles (virion + 22nm particles) per ml. Antibody to hepatitis B surface antigen (anti-HBs) becomes detectable during the recovery from acute HBV infection in patients who do not progress to a chronic infection. The disappearance of the HBsAg occurs a few weeks before the advent of the anti-HBs. The presence of anti-HBs after acute infection indicates recovery from the infection and generally lifelong immunity from reinfection. A measurable anti-HBs response, which can vary among subjects, is as well induced in most recipients of HBV vaccine. An other interesting marker of acute HBV infection is the anti-HBc antibodies of the IgM class which appear shortly after HBsAg and remain detectable up to 6 month after the onset of the acute hepatitis. The detection of the IgM anti-HBc is of interest in diagnosing an acute infection in patients with HBsAg concentrations that are below the sensitivity threshold of the diagnostic assay. Moreover a high titer of this marker is generally accepted as an indicator for acute infection. Anti-HBc IgM may also become detectable in chronic HBV infection in case of viral reactivation and acute exacerbation of the liver disease. A third very useful hepatitis serological marker is HBeAg, which usually becomes detectable in the serum when HBsAg first appears. The presence of HBeAg in serum correlates with the presence of viral replication in the liver. During a typical acute infection, HBeAg is detectable early in the course of disease and disappears within several weeks as hepatitis resolves. In chronic hepatitis B, HBeAg is an important marker to monitor as it usually remains detectable for many months or years, indicating active replication of the virus and potential ongoing liver injury. Moreover, the loss of HBeAg and acquisition of anti-HBe (seroconversion) by chronic carriers tend to be associated with biochemical and histochemical improvement, with the notable exception of pre-core mutants. HBeAg in serum can be detected by a sandwich immunoassay format similar to that for HBsAg. The above mentioned points occur in HBV infection with typical course (Table 1). Sometimes, the immunologic pattern is different. This can be due to an error in the evaluation using immunological techniques or to an atypical pattern, whose can include i) isolated anti-HBc positivity, ii) simultaneous HBsAg and anti-HBs. To avoid misdiagnosis, additional tests involving detection of circulating HBV DNA have been implemented in routine laboratory analysis.

HBV感染的血清学诊断：急性或慢性HBV感染的血清学标志物不同(表1)。HBV感染最初的血清学标志物是HBsAg，它在HBV感染后的2~24周可以检测到。HBsAg常常在临床症状或肝生化指标异常（如ALT升高）前6~8周出现。恢复期患者，HBsAg在2~6个月内从血清中消失，在不固定的窗口期后，保护性抗HBs抗体出现。感染发生6个月后HBsAg持续存在，被广泛认为一种慢性感染的标志。HBsAg检测是应用最广泛的HBV感染诊断试验。在以往夹心酶联免疫吸附测定法（ELISA）基础上的一种改良方法，包括固相微粒和计算机操作，目前被用于检测HBsAg(77)。这些微粒酶免疫测定法（MEIAs）能快速检测到100-200pg/ml HBsAg，相当于大于3.107个颗粒/ml（病毒体 +22nm颗粒）。急性HBV感染恢复后，如患者未进展至慢性感染，则可以检测到乙肝表面抗原抗体（抗HBs）。抗HBs出现前几周，HBsAg已消失。急性感染后抗HBs出现提示感染恢复，一般可获得对再感染的终身免疫。尽管存在个体差异，在大部分HBV疫苗接种者中，也可以检测到抗HBs存在。另一个有意义的急性HBV感染标志物是抗HBc IgM抗体,它在HBsAg出现后短期内出现，在急性感染6个月内都可以检测到。当急性感染者的HBsAg浓度低于诊断方法的敏感度阈值时，抗HBc IgM检测就体现出意义。高滴度的该标志物通常被认可为为急性感染标志。慢性感染时当病毒再复制和肝病急性加重也可检测到抗HBc IgM。第3个有用的肝炎血清标志物是HBeAg，通常当HBsAg刚出现时即可以检测到。血清中HBeAg的存在与肝脏病毒复制有关。在典型急性感染期间，HBeAg在疾病早期可以检测到，在肝炎恢复几周内消失。在慢性乙肝，HBeAg是一种重要的监测标志物，常持续数月或数年阳性，提示病毒复制活跃，肝损伤仍在进展。此外，慢性携带者HBeAg消失并且抗HBe出现（血清转换）常伴有生化学和组织学改善，此时需注意排除前C区变异。血清HBeAg通过夹心免疫测定法进行检测，与HBsAg相似。以上谈到的几点出现在HBV感染典型过程中(Table 1)。有时，免疫模式有不同之处。这可能是免疫技术评估当中的误差，或者非典型模式，可能包括i）单独抗HBc阳性，ii)HBsAg和抗HBs同时阳性。为了避免误诊，加做循环HBV DNA检测在内的试验作为常规实验室检测的补充。

Molecular Diagnosis of HBV Infections: Determination of HBV DNA levels in serum is now accepted as part of the serological profile for screening of blood donors and for monitoring the ongoing viral replication in patients with diagnosed chronic hepatitis B (even when HBeAg is not detectable), or the response to therapy. It is also useful as a prognostic index regarding response to interferon therapy. For instance, patients with HBV DNA concentrations <200 pg/ml are more likely to have a successful therapeutic outcome than those with higher HBV DNA concentrations. The currently commercialized tests are of three types: quantitative hybridization-based assays (e.g. Digene Hybrid-Capture from Murex Diagnostics), branched-DNA assays (e.g. Versant bDNA version 3.0, Bayer Diagnostics), polymerase chain reaction (PCR) assays (e.g. Amplicor HBV monitor from Roche), and real time PCR assays (Roche Diagnostics and Abbott). All the techniques have reasonable specificity and reproducibility, but have different range of linear quantification (11, 160, 264). The PCR-based assays have a good sensitive with a threshold of detection at 400 genomes/mL (~ 1 fg/ mL). The real time PCR based assays have the best range of detection and sensitivity limit of approximatively 50 copies/ml. Caution is necessary when using different commercial kits as their internal standards are not equivalent. To resolve this problem, the European Expert Group on Viral Hepatitis have formulated a consensus preparation of an HBV DNA-positive plasma and assigned to it a concentration in Eurohep Units (EU), with 1 EU being equivalent to about 1 to 2 molecules of HBV DNA (373). The use of this international standard facilitates comparisons and allows harmonization in clinical and laboratory practice.

HBV感染的分子生物学诊断：血清HBV DNA水平测定目前已作为血清学检测的一部分，用来筛查献血员，监测慢性乙肝患者病毒复制（即使在HBeAg检测不到的情况下），或对治疗的应答情况。关于干扰素的治疗应答，它也是有用的预后指数。例如，HBV DNA浓度<200 pg/ml的患者较HBV DNA高浓度患者相比，更可能治疗成功。目前有三种类型的商业化检测方法：定量杂交测定法（如Murex Diagnostics公司的 Digene Hybrid-Capturetics），分支DNA法（如拜耳诊断公司的Versant bDNA version 3.0），聚合酶链反应（PCR）法（如罗氏公司的Amplicor HBV monitor）以及实时PCR法（罗氏诊断和雅培公司）。所有方法都有很好的特异性和可重复性，但有不同的线性定量范围(11, 160, 264)。PCR法敏感性好，检测阈值为400基因/mL（~ 1 fg/ mL）。实时PCR有最佳检测范围，检测灵敏度极限大约50 copies/ml。值得注意的是不同商业试剂盒它们的内部标准不相同。为解决这个问题，欧洲病毒性肝炎专家组达成一致意见，制备了1份HBV DNA阳性血清，指定它的浓度单位为Eurohep Units (EU)，1EU相当于1~2个分子的HBV DNA(373)。这一国际标准的应用使得在临床和实验室实践能协调一致，具有可比性。

Since the introduction of antiviral agents (e. g. lamivudine) for the treatment of patients with chronic hepatitis B, the accumulation of a variety of mutations in the HBV polymerase gene has been observed (Figure 3). The detection of these variants is of clinical importance, as they may be associated to nonresponsiveness and treatment failure. Innogenetics has developed a line probe assay (INNO-Lipa HBV polymerase drug resistance) for monitoring drug resistance in HBV-infected patients before and during antiviral therapy. This assay is based on nitrocellulose strips on which are fixed different probes corresponding to different known mutations in the catalytic domain (C domain), that includes the YMDD motif and in the B domain. The viral DNA, purified from patient’s serum, is first amplified by PCR then hybridized to the strips in order to determine the local genetic pattern of the patient (319). An alternative to this assay is to use PCR amplification and sequencing of the polymerase gene. But this technique is less common in routine laboratory diagnosis.

　　自抗病毒药物（如拉米夫定）用于治疗慢性乙肝患者以来，在HBV聚合酶基因上观察到累积存在多种变异(图3)。这些变异的检测有重要临床意义，它们可能与治疗无应答和治疗失败有关。Innogenetics已经发展出一种线性探针分析（INNO-Lipa HBV多聚酶耐药性），用于监测HBV感染患者抗病毒治疗前和治疗中的耐药性。该方法以固定了不同探针的硝酸纤维素膜为基础，这些探针与催化区（C区）上已知的不同变异相对应，包括YMDD基序和B区。从患者血清中提纯病毒DNA，首先通过PCR扩增，然后与膜杂交，以测定患者的局部基因序列(319)。该法另一种方式是PCR扩增，然后进行聚合酶基因测序。但该技术在常规试验诊断中少见。

FDA: FDA Approves First Nucleic Acid Test to Screen for Additional Types of HIV In Donated Blood and Tissues. December, 2008. http://www.fda.gov/bbs/topics/NEWS/2008/NEW01936.html

(Printable Version of Laboratory Diagnosis for Hepatitis B Virus)

Pathogenesis Guided Medline Search

发病机制

The pathogenesis of hepatitis B virus infections has been abundantly reviewed elsewhere (111, 126, 142, 194, 251, 278, 296), and only a very brief summary will be given here. HBV is generally considered to be noncytopathic, meaning that its replication does not induce directly cellular damage. Instead, liver cell damage is self-inflicted and occurs when the immune system either clears the infection in the case of resolving acute HBV infection or repetitively attempts to clear the infection in the case of chronic viral infection. The effectors that mediate this immune response responsible for liver injury are diverse. Earliest intervention of the host response likely involves the non-specific innate immune system that includes macrophages, neutrophils, natural killer cells as well as diverse cytokines (278). The effectors of the specific adaptive immune response are of two kinds. They are antibodies that reduce viral load and prevent infection of non-infected cells. More importantly in respect with pathogenesis, CD8+ T cells that induce necroinflammatory or apoptotic destruction of virus-infected cells or, alternatively, may suppress viral replication in infected cells by the production of TH1 cytokines independently of cell lysis. Necroinflammatory damage may be virus-specific or non-specific and may involve participation of cells of the non-specific immune system. Most often, the interplay of the immune mechanisms brings about elimination of the virus over varying periods of time. In chronic infection the immune system may be too weak to clear infected-cells, but sufficient to induce the lysis of a part of them. Alternatively persistence might be the result of a particularly efficient virus with enhanced or modified replication properties. Altogether, the repetitive immune attack by CD8-positive cytotoxic T lymphocytes and other NK-T cells is probably responsible for the progressive liver injury.

　　HBV感染的发病机制在其他文献中已有大量的综述(111, 126, 142, 194, 251, 278, 296)，本文只作简略的概述。通常认为HBV为非细胞毒性，即HBV复制并不直接引起细胞损伤。相反，肝细胞损伤是机体本身自我造成的；在自限的急性HBV感染时，机体免疫系统清除感染，或者在慢性HBV感染的情况下，免疫系统反复试图清除HBV时会引起肝细胞损伤。介导肝细胞损伤的免疫应答效应因子多种多样。宿主应答最早期干预可能与非特异先天性免疫系统参与有关，包括巨噬细胞，中性粒细胞，自然杀伤细胞以及各种细胞因子等 (278)。特异性获得性免疫应答效应因子有两种。有降低病毒载量防止未感染细胞被感染的抗体。更重要的是，CD8+ T淋巴细胞，它诱导坏死性炎症或凋亡破坏被病毒感染的细胞，或者可通过产生非细胞溶解性TH1细胞因子，抑制HBV感染细胞的病毒复制。坏死性炎症损伤可能是病毒特异性的，或病毒非特异性的，涉及非特异性免疫系统细胞的参与。大多数时候，经过不同时间，免疫机制相互作用引起病毒清除。HBV慢性感染时，免疫系统可能太弱不足以清除感染的细胞，但足以降低引起部分细胞溶解。相对持久的HBV感染可能是部分病毒增强或改良复制特性的结果。总而言之，进行性肝损伤很可能由CD8+细胞毒性T淋巴细胞和其它NK-T细胞反复免疫攻击所致。

The most serious pathologic consequences of chronic hepatitis B are cirrhosis of the liver, and hepatocellular carcinoma (HCC). Approximately 10 to 25% of chronic carriers die from either cirrhosis or hepatocellular carcinoma (194, 296). The origin of cirrhosis, that results from long-term inflammation cell death, and replacement with non-parenchymal (fibrotic) tissues, is well defined and understood. But, the mechanism and role of the virus in the induction of hepatocellular carcinoma is still a complex issue. Hepatocellular carcinoma is among the most common cancers in the world and one of the rare human cancer to show sero-epidemiological association with viral infection. The role of HBV as a major etiological agent of hepatocellular carcinoma has been firmly established, and the increased risk of developing hepatocellular carcinoma has been estimated to be 100 fold for chronic HBV carriers as compared with noninfected populations (18, 19). Although the details of this process are still not understood, the field has been driven by two hypotheses, one positing a direct effect of the virus in cancer development, the other predicting that hepatocellular carcinoma formation is a consequence of persistent liver injury caused by the immune response against infected hepatocytes and hence, attributing an indirect role to the virus.

　　慢性乙肝引起的最严重的病理结果是肝硬化和肝细胞癌（HCC）。大约10-25%的慢性HBV携带者死于肝硬化或肝细胞癌(194, 296)。肝硬化的病因已明确认识，它是长期炎症细胞坏死和非实质（纤维）组织替代的结果。但HBV诱导肝细胞癌的机制和作用仍是一个复杂的问题。肝细胞癌是世界上最常见的恶性肿瘤之一，也是是可显示血清流行病学与病毒感染关系少见的人类恶性肿瘤之一。作为肝细胞癌主要病原，HBV作用已经非常明确；据估计，慢性HBV携带者发生肝细胞癌的风险较未感染HBV者增加100倍 (18, 19)。尽管发病过程的细节还不清楚，但存在两种假设：一种认为病毒在肿瘤形成中起直接作用，另一种预测肝细胞癌形成是持续肝细胞损伤的结果，而肝损伤是由机体抗HBV感染肝细胞免疫应答所致，病毒起间接作用。

Evidence for a direct mechanism was fueled by the observation that DNA from hepatocellular carcinoma contained integrated HBV DNA and that tumors were clonal with respect to the viral integration site (93). This discovery was consistent with the model of insertional mutagenesis coined by retrovirologists to describe the activation of proto-oncogenes by retroviruses (138, 265). However efforts to identify candidate genes adjacent to integrated HBV DNA were not met with success save for a few isolated cases, where integration sites were found adjacent to or within coding regions of candidate proto-oncogenes including cyclin A, erb-A or retinoic acid receptor beta (78, 79, 352). Alternative models consistent with a direct mechanism posit that one or several viral gene products are oncogenic. Although the long latency period observed for hepatocellular carcinoma development indicates that HBV gene products cannot transform hepatocytes in a single hit event, the hypothesis gained momentum with the discovery that transgenic mice expressing HBx developed hepatocellular carcinoma (161). However, it became rapidly clear that the success of this model depended on the selection of the mouse strain, CD1, known to develop spontaneous hepatomas at an increased rate compared to other mouse strains, and high expression levels of the transgene that are not observed during natural infections (165). However, it appears that HBx transgenic mice are more susceptible to hepatocellular carcinoma induction by diethylnitrosamine (308), as are mice expressing HBx and c-myc (327). These and other observations invoke the possibility that HBx could, at best, contribute to a multistep transformation process by either activating certain signal transduction pathways or by binding to host proteins, such as the DNA repair protein UVDDB or the proteasome subunit XAPC7 (149, 193). Also, it is important to consider that HBx is not always expressed in hepatocellular carcinoma (320). In addition, as stated earlier, tumors are normally not permissive for HBV infection. Therefore, it is unlikely that the protein acts as an oncogene that is required to maintain the transformed phenotype. The discovery of the transactivation function of truncated M envelope proteins rekindled the viral oncogene hypothesis, in particular since the mutant genes were occasionally found in hepatocellular carcinomas (293). Transgenic mice over-expressing the HBV L-protein develop hepatocellular carcinoma (54).

　　研究发现，肝细胞癌中DNA含有整合型HBV DNA，且肿瘤与病毒整合位点属同源细胞，这为直接作用机制的存在提供了依据(93)。该发现与逆转录病毒学家提出的插入诱变模型相符，后者用来说明逆转录病毒对原癌基因的激活作用 (138, 265)。然而，除了少数个别基因之外，为鉴定与整合型HBV DNA相邻的候补基因所作出的努力并没有取得成功，整合位点部位被发现毗邻或在候补原癌基因编码区内，包括细胞周期蛋白A，生长因子受体或视黄酸受体β(78, 79, 352)。符合直接作用机制的其它模型证实，存在一种或几种致癌性病毒基因产物。虽然观察到肝细胞癌形成需要较长的潜伏期，提示HBV基因产物不能直接作用转化肝细胞，但由于研究发现表达HBx转基因小鼠可发生肝细胞癌，促进了这一假设的发展(161)。然而，很明显该模型的成功取决于小鼠品系的选择，较其他小鼠品系相比，可形成自发性肝癌的CD1水平以一定比率增加，并且与在自然感染过程中不能观察到的转基因高表达有关(165)。但研究表明，HBx转基因小鼠经二乙基亚硝胺诱导更容易发生肝细胞癌 (308)，正如表达HBx和原癌基因c-myc的小鼠一样(327)。这些研究及其他研究认识到，HBx最大程度可能通过激活某些信号转导途径或与宿主蛋白结合，如DNA修复蛋白UVDDB或蛋白酶体亚基XAPC7，有助于形成一个多级转化过程 (149, 193)。而且，HBx并不一定仅在肝细胞癌中表达，这是需要认识的一个重要问题(320)。此外，如前所述，正常情况下HBV不能感染肿瘤细胞。因此，蛋白不可能作为原癌基因，持续维持表型转化。截短包膜蛋白M转活功能的发现，重新点燃了病毒致瘤基因假设，尤其是在肝细胞癌中偶然发现突变基因后(293)。HBV L-蛋白过表达转基因小鼠可发生肝细胞癌(54)。

Models explaining hepatocellular carcinoma development by indirect mechanisms take into consideration a hallmark of HBV infections, cell death and regeneration of hepatocytes. While this process is inconsequential on a sporadic basis, it can cause substantial fibrosis and cirrhosis of the liver under persistent condition such as those observed in chronic alcohol abuse, storage disease and chronic HBV or HCV infections. Independent of the cause, chronic liver disease is associated with hepatocellular carcinoma. It was suggested that a contributing factor in emergence of hepatocellular carcinoma was free radicals generated by the large number of macrophages activated in response to the high rate of apoptosis, leading to extensive hepatocyte DNA damage. A possibility is that DNA damage is the underlying cause of hepatocellular carcinoma and that hepatocyte proliferation in response to cell death facilitates emergence of mutated cells. Recent cohort studies performed in Asia demonstrated a link between the level of viral load and the subsequent risk of developing hepatocellular carcinoma (49).

　　说明间接作用机制导致肝细胞癌形成的模型，要考虑到HBV感染的特征，细胞坏死和肝细胞再生。虽然这一过程单独作为基础时不会造成严重后果，但在长期慢性酗酒、贮积症和慢性HBV 或 HCV感染情况下，可引起肝实质纤维化和肝硬化。即使没有这些原因，慢性肝病也与肝细胞癌有关。研究显示，大量的巨噬细胞活化产生的自由基带来的高凋亡率，可导致大量的肝细胞DNA损伤，是肝细胞癌发生的影响因素。一种可能性是DNA损伤是肝细胞癌的主要原因，细胞坏死后肝细胞增殖促进了细胞发生突变。亚洲近来的队列研究证明了病毒载量水平和肝细胞癌发生风险之间的关系(49)。　

SUSCEPTIBILITY IN VITRO AND IN VIVO OF HBV TO ANTIVIRALS Guided Medline Search In Vitro and In Vivo

HBV对抗病毒药物体外和体内的敏感性

HBV belongs to the Hepadnaviridae, a virus family that includes the woodchuck hepatitis virus (WHV (322), the duck hepatitis virus (DHBV) (231), the ground squirrel hepatitis virus (GSHV) (295), and the more recently described viruses, heron hepatitis virus (HHV) (313), snow goose hepatitis virus (SGHV) (44) and woolly monkey hepatitis virus (WMHV) (183). All members of this family share homology in their genome organization, viral particle structure and strategy of replication. They offer opportunities for in vivo study and in vitro studies when cell lines are available. Antiviral agents have been studied extensively in the DHBV and the WHV systems. The duck system offers the advantages of being relatively inexpensive and readily available, in comparison to the woodchuck model. However, the woodchuck model is particularly useful because it is a mammalian virus, thus closer to HBV, and chronic infection in the woodchuck leads to hepatocellular carcinoma within 2 to 3 years (226).

　　HBV属于肝DNA病毒科，该病毒属包括土拨鼠肝炎病毒（WHV）(322)、鸭肝炎病毒（DHBV）(231)、地松鼠肝炎病毒（GSHV）(295)，以及近来发现的苍鹭肝炎病毒（HHV） (313)、雪雁肝炎病毒（SGHV）(44)和绒毛猴肝炎病毒（WMHV）(183)。该病毒属所有成员在它们的基因组组成、病毒颗粒结构和复制策略上具有同源性。有了可利用的细胞系为病毒的体内和体外研究提供了机会。抗病毒药物在DHBV 和WHV模型中被广泛研究。较WHV模型相比，DHBV模型具有价格相对便宜，容易获取等优点。然而，WHV模型尤为重要，因为WHV是一种哺乳动物病毒，更接近HBV, 并且WHV慢性感染在2-3年内会引发肝细胞癌(226)。

Efficacy of HBV-infection in primary human hepatocytes cultures (108) is low and primary liver cells become non-permissive for infection within days after plating. Moreover, unlike animal tissues, access to human liver is limited and clearly human hepatocytes cannot be used for routine screening of anti-HBV agents. Only recently, a hepatoma cell line was shown to be susceptible to HBV infection under specific conditions, but the full potential of this cell line is still under investigation (123). These difficulties are circumvented by several in cell culture systems, which have proven very useful for the screening of anti-HBV compounds and study of their mode of action. They are i) stably transfected hepatoma lines HepG 2.2.15 or HepAD38, ii) transiently transfected hepatoma cell lines (HepG2 or Huh-7 human cells for HBV and LMH avian cells for DHBV), and iii) infected hepatoma cell lines via recombinant HBV-baculovirus that allow full viral replication including ccc-DNA formation. Furthermore, determination of the mode of action may be investigated i) in primary cultures of hepatocytes taken from the well-characterized animals models of HBV, the duck and the woodchuck, ii) on endogenous viral DNA and RNA dependant DNA polymerase which can be assayed in purified nucleocapsid or iii) in a tube reconstituted assay for both priming and reverse transcription of the viral genome. Each of these different in vitro systems presents different advantages, inconveniences and limitations that have been discussed extensively (135, 381).

　　HBV感染培养的人原代肝细胞效率低(108)，而且培养数天内原代肝细胞即不再易受感染。此外，不像动物组织，人的肝脏来源有限，显然不能常规应用人肝细胞筛选抗HBV药物。直到最近才发现一个在特定条件下对HBV易感的肝癌细胞系，但其全部潜能仍在研究中(123)。这些困难已被细胞内培养系统避开，细胞内培养系统对于抗HBV药物的筛选及其作用方式非常有用。它们包括：i）稳定转染的肝癌细胞系HepG 2.2.15或HepAD38，ii）暂时转染肝癌细胞系（针对HBV的 HepG2或Huh-7 人细胞，以及针对DHBV 的LMH的禽类细胞），iii）被HBV-杆状病毒重组病毒感染的肝癌细胞系，能使病毒完全复制，包括ccc-DNA形成。此外，作用方式的确定需要进一步研究：i）从具有HBV、DHBV、WHV良好特征的动物模型中提取肝细胞进行原代培养；ii）可在纯化核衣壳内测定内生性病毒DNA和 RNA依赖的DNA多聚酶；iii）管重组法用于检测病毒基因组的启动和逆转录作用。各种来源不同的体外系统，呈现出不同的优势、不便和局限性，这些已被深入的研究(135, 381)。

All these in vitro and animal models contributed to the molecular characterization of the replication cycle of HBV and consequently to the identification of viral targets for antiviral therapy of HBV infection (Figure 2): i) neutralization of the virus-cell interaction with anti-envelope antibodies or peptides, (ii) cytokine and/or antisense inhibition of viral transcription and viral gene expression, (iii) packaging inhibition with peptides, (iv) RNA or DNA dependent DNA polymerase activity inhibition by nucleoside analogs or antisense and (v) viral secretion with glucosidase inhibitors.

　　所有体外和动物模型均有助于HBV复制周期的分子鉴定，从而有助于识别HBV感染抗病毒治疗的病毒靶点(图2)：i）用抗外膜抗体或多肽中和病毒和细胞的相互作用，ii）细胞因子和/或病毒转录和病毒基因表达的反义抑制，iii）利用多肽包装抑制物，iv）核苷类似物对依赖RNA 或 DNA的DNA多聚酶活性的抑制或反义抑制，v）利用葡萄糖苷酶抑制剂抑制病毒分泌。

Antiviral therapy has to face the problem of viral persistence and resistance to nucleoside analogs and thus since several years the field of drug discovery continues to be extremely active to find new agents (75, 95, 124, 134, 303, 382, 385).

　　抗病毒治疗必须面对病毒持续感染和核苷类似物耐药的问题，因此，在今后几年，寻找新的抗病毒药物将持续成为药物研发领域的热点(75, 95, 124, 134, 303, 382, 385)。

Single Drugs (Table 2)

Nucleoside/ Nucleotide Analogues

核苷/核苷酸类似物

Cytidine analogues

胞嘧啶核苷类似物

Lamivudine: Lamivudine or 3TC (beta-L-2', 3'-dideoxy-3'-thiacytidine) is a potent in vitro inhibitor of both duck (302) and human hepadnaviruses (Table 2) (41, 89), acts as chain terminator of the reverse transcription (302), and has no mitochondrial toxicity (70, 156). Interestingly, it was shown, using an HBV-baculovirus system infecting HepG2 cells, that lamivudine has also an inhibitory activity on ccc-DNA synthesis and accumulation (82). Lamivudine is a very effective inhibitor of DHBV in ducks (190), and HBV in chimpanzees, but only a moderate inhibitor of WHV in woodchucks (230). Consistently with the latter observation, it was observed that a prolonged 3TC treatment on primary woodchuck hepatocytes infected by WHV does not allow viral eradication (242). Treatment with lamivudine is as well associated with viral resistance (47, 210, 330). Variants presenting mutations within the catalytic domain (C domain), which includes the YMDD motif, (e. g. YVDD and YIDD), and within the B domain (e. g. L180M, frequently associated with YVDD) have been identified and studied to determine their biological features. It was found that these mutants have a reduced replicative capacity compared to the wild-type virus (101, 239, 299). To find an alternative treatment for 3TC resistant patients, many works on the susceptibility of these mutants to others drugs were performed in vitro and animal models (28, 53, 90, 104, 259, 260, 299, 371). Two categories of drug have been characterized; those which present a cross-resistance pattern with 3TC, such as the pyrimidine analogues emtricitabine, beta-L-Fd4C, or clevudine and those which are active against 3TC-resistant mutants, such as the purine analogues such as adefovir, ganciclovir, entecavir or amdoxovir. Details on these drugs follow.

拉米夫定：拉米夫定或3TC（β-L-2', 3'-双脱氧-3'-硫代胞嘧啶）是鸭 (302)和人肝DNA病毒体外研究中一种有效的抑制剂(表2) (41, 89)，它作为病毒逆转录时的链终止物(302)，且无线粒体毒性(70, 156)。有趣的是，实验显示，采用HBV杆状病毒感染HepG2细胞系统中，拉米夫定对ccc-DNA的合成和累积也有抑制作用(82)。拉米夫定是鸭的DHBV(190)和猩猩的HBV的一种非常有效抑制剂，但对土拨鼠的WHV仅中度抑制(230)。与近来的研究结果一致，对WHV感染的原代土拨鼠肝细胞延长3TC治疗时间，并不能根除病毒(242)。用拉米夫定治疗也可产生病毒变异(47, 210, 330)。含YMDD基序（如YVDD和YIDD）的催化区（C区）和B区（如L180M，常伴有YVDD的出现）内的变异株已被鉴定，并被研究确定其生物特征。研究发现，较野生株相比，这些病毒变异株复制能力下降(101, 239, 299)。为了找到一种替代药物用于治疗3TC耐药的患者，研究者进行了大量体外和动物实验(28, 53, 90, 104, 259, 260, 299, 371)，用来研究变异株对其它药物的敏感性。已鉴定了两类药物，一类与3TC存在交叉耐药结构，如嘧啶类似物恩曲他滨，β-L-Fd4C，或克来夫定；另一类是对3TC耐药变异株有抑制活性，如嘌呤类似物阿德福韦，更昔洛韦，恩替卡韦，或氨多索韦。有关这些药物的详细介绍如下：

Emtricitabine: Emtricitabine or FTC (beta-L-2',3'-dideoxy-5'-fluoro-3'-thiacytidine) is a 5-fluoro oxathiolane derivative, closely related to lamivudine. It was found to be a potent inhibitor of HBV replication in the HepG 2.2.15 (107), in primary human hepatocytes, and in vivo in nude mice (65). In the woodchuck animal model, FTC reduced WHB DNA significantly in a dose dependent manner, showing antiviral activity levels similar to those obtained with lamivudine (73, 170). Cross-resistance between lamivudine and FTC has been reported, thus precluding its use in the treatment of patients with lamivudine-resistant variants (101, 173).

恩曲他滨：恩曲他滨或FTC（β-L-2',3'-dideoxy-5'-氟-3'-硫代胞嘧啶)是一种5-氟氧硫环衍生物，与拉米夫定类似。研究发现，它可有效抑制HepG 2.2.15 (107)，原代人肝细胞和裸鼠体内(65)HBV的复制。在土拨鼠动物模型中，FTC剂量依赖性的显著降低WHB DNA，显示其抗病毒活性与拉米夫定相同 (73, 170)。已报道拉米夫定和FTC的存在交叉耐药性，因此，不能使用该药治疗拉米夫定耐药变异的患者 (101, 173)。

Elvucitabine: Elvucitabine or Beta-L-Fd4C (beta-L-2',3'-dideoxy-2'3'-didehydro-5-fluorocytidine) inhibits HBV replication in the HepG 2.2.15 cell line, without inducing significant mitochondrial DNA toxicity in CEM cells (50, 307). Evaluation in the DHBV infection model showed that beta-L-Fd4C is a more potent inhibitor of the DHBV RT than 3TC and other cytidine analog triphosphates and inhibits viral DNA synthesis in primary duck hepatocyte cultures. It was also demonstrated that early administration of beta-L-Fd4C after experimental infection of ducklings dramatically inhibits viral replication but does not prevent the progression to chronic infection (190). Furthermore, in woodchucks chronically infected with WHV, although beta-L-Fd4C activity was more potent than 3TC, it did not allow clearance of viral ccc-DNA and infected cells from the liver (191). Lamivudine-resistance mutations also confer resistance to elvucitabine (28).

艾夫他滨：艾夫他滨或β-L-Fd4C（β-L-2',3'-双脱氧-2'3'-二脱氢-5-氟胞嘧啶核苷)可抑制HepG 2.2.15细胞株内HBV的复制，在CEM细胞中无明显线粒体DNA毒性作用(50, 307)。对DHBV感染模型的评估显示，β-L-Fd4C是一种比3TC及其他胞嘧啶核苷类似物三磷酸盐更有效的DHBV RT抑制剂，可抑制原代鸭肝细胞病毒DNA的合成。研究证实，实验鸭感染后，早期予以β-L-Fd4C治疗能显著抑制病毒复制，但并不能阻止感染慢性化 (190)。此外，在WHV慢性感染的土拨鼠中，尽管β-L-Fd4C抗病毒活性优于3TC，但并不能清除病毒ccc-DNA和已感染的肝细胞(191)。拉米夫定耐药变异也对艾夫他滨耐药(28)。

Thymidine analogues

脱氧胸腺嘧啶核苷类似物

Clevudine: Clevudine or L-FMAU (2'-Fluoro-5-Methyl-beta-L-Arabinofuranosyluracil) is a beta-L-nucleoside analogue derived from deoxythymidine (TTP) which was found to be a potent inhibitor of hepatitis B virus (HBV) replication in HepG 2.2.15 and to have a low in vitro cytotoxicity (55). In this cell line, it was further demonstrated that L-FMAU inhibits HBV without affecting the host DNA synthetic machinery (12). By contrast to D-FMAU and to D-FIAU, L-FMAU does not decrease mitochondrial DNA content, does not affect mitochondrial function, and is not incorporated in cellular DNA (12). Moreover, Aguesse-germon et al. (1) showed that L-FMAU exhibits antiviral activity in vivo in experimentally infected ducklings and primary duck hepatocytes. Interestingly, L-FMAU is a weak inhibitor of the reverse transcriptase activity, but an inhibitor of the DNA-dependent DNA polymerase activity (301). Lamivudine-resistance mutations also confer resistance to L-FMAU (28). L-FMAU may have additional modes of action, such as immunological modulation, since more than 50% of patients under treatment with L-FMAU for 3 months show a slow viral rebound for at least a 6 months period after treatment withdrawal (225). Despite a potent inhibition of viral replication when used alone or in combination with emtricitabine in chronically infected woodchucks, experimental studies showed the persistence of viral ccc-DNA (154, 377).

克来夫定：克来夫定或L-FMAU (2'-氟-5-甲基-β-L-阿拉伯呋喃糖尿嘧啶)，是从脱氧胸腺嘧啶核苷（TTP）中获得的一种β-L-核苷类似物，研究发现TTP是HepG 2.2.15中乙肝病毒（HBV）复制一种有效的抑制剂，有较低的体外毒性 (55)。在该细胞株中，进一步的证实，L-FMAU能抑制HBV，而且不影响宿主DNA合成机制 (12)。与D-FMAU 和D-FIAU相反，L-FMAU不减少线粒体DNA含量，不影响线粒体功能，不与细胞DNA整合(12)。此外，Aguesse-germon等(1)研究发现，L-FMAU在实验感染鸭体内和原代鸭肝细胞具有抗病毒活性。有趣的是，L-FMAU抑制逆转录酶的活性较弱，但能有效抑制依赖DNA的DNA多聚酶活性(301)。拉米夫定耐药变异也对L-FMAU耐药 (28)。L-FMAU可能存在其它的作用方式，如免疫调节，因为50%的患者L-FMAU治疗3个月，停止治疗后，至少在6个月内，病毒反跳缓慢(225)。虽然在慢性感染土拨鼠中单药治疗或与恩曲他滨联合治疗，L-FMAU都能有效抑制病毒复制，但实验研究显示病毒ccc-DNA持续存在 (154, 377)。

Telbivudine: Telbivudine or LdT (beta-L-2’-deoxythymidine), is a compound of the novel class of the beta-L-nucleosides with potent, selective and specific activity against hepadnavirus (274). In vitro studies have shown that this compound have marked effects on HBV replication (13). In woodchuck chronically infected with woodchuck HBV, up to 28 days of LdT treatment produced consistent, multilog reductions in circulating serum woodchuck HBV DNA levels. Toxicology strudies conducted with rats and monkeys revealed no clinical abnormalities (31).

替比夫定: 替比夫定或LdT（β-L-2’-脱氧胸腺嘧啶核苷）是一种新的β-L-核苷类药物，对肝DNA病毒具有高效、选择性和特异性抗肝DNA病毒活性(274)。体外研究显示，该药对HBV复制有显著作用(13)。在慢性感染WHBV土拨鼠，长达28天的治疗中，LdT持续、多个数量级地降低了血浆循环WHBV DNA载量。在鼠和猴的进行的毒理学研究并未出现临床异常情况(31)

Adenosine analogues

腺苷类似物

Adefovir Dipivoxil: Adefovir dipivoxil or PMEA [9-(2-phosphonolmethoxyethyl) adenine] is an acyclic phosphonate nucleotide analogue of adenosine monophosphate, which, unlike nucleoside analogues, does not require the first of three phosphorylation steps for conversion to the active triphosphate form. In vitro, adefovir diphosphate, the active metabolite of adefovir is a potent inhibitor of viral replication in human hepatoma cells lines stably transfected with HBV and in primary duck hepatocytes infected with DHBV (140). The antihepadnaviral activity of adefovir dipivoxil was also demonstrated in vivo, in the duck model (139) and in woodchucks chronically infected with the woodchuck hepatitis virus (WHV) (72). Although, adefovir dipivoxil is a more potent inhibitor of DHBV replication than lamivudine in experimentally infected ducklings and primary duck hepatocytes, it does not prevent ccc-DNA synthesis and accumulation (83). The most important feature of adefovir dipivoxil resides on its capacity to inhibit the replication of lamivudine-resistant (259, 363), but several resistant variants that are inert to PMEA treatment have been detected according to recent reports (7, 346).

阿德福韦酯：阿德福韦酯或PMEA [9-[2-[双(新戊酰氧甲氧基)磷酰甲氧基]乙基]腺嘌呤]是一种单磷酸腺苷的无环磷酸核苷酸类似物，与核苷类似物不同，阿德福韦酯不需要三磷酸化步骤中第一步磷酸化就可以转化为有活性的三磷酸盐形式。阿德福韦体外活性代谢产物，阿德福韦二磷酸盐，能有效抑制HBV稳定转染人肝癌细胞系和DHBV感染原代鸭肝细胞中的病毒复制(140)。阿德福韦酯抗肝DNA病毒活性在鸭模型(139)和WHV慢性感染的土拨鼠模型等体内实验中也被证实(72)。尽管较拉米夫定相比，阿德福韦酯在实验感染鸭和原代鸭肝细胞中能更有效的抑制DHBV复制，但它不能阻止ccc-DNA的合成和累积 (83)。阿德福韦酯最重要的特性在于它具有抑制拉米夫定耐药病毒复制的能力 (259, 363)，但近来报道发现，也存在一些耐药变异株对PMEA治疗无应答 (7, 346)。

Tenofovir: Tenofovir or PMPA belongs to a class of acyclic phosphonate nucleotide analogues which have demonstrated clinical utility against a broad spectrum of viral infections. PMPA has selective activity against retroviruses and hepadnaviruses and is currently approved for the treatment of HIV-1 as the bis-alkoxyester prodrug tenofovir disoproxil fumarate. PMPA was shown to be active against DHBV and HBV in vitro (140), and more recently against WHBV in vivo (240). PMPA has demonstrated full activity against lamivudine-resistant variants, as well as against multiple drug resistant strains in vitro and clinically (28, 80, 338, 348, 365).

替诺福韦：替诺福韦或PMPA，属于无环磷酸核苷酸类似物，证实具有临床广谱抗病毒作用。PMPA对逆转录病毒和肝DNA病毒有选择性抗病毒活性，目前富马酸替诺福韦酯作为其前体药物已批准用于治疗HIV-1。PMPA显示有抗DHBV 和HBV体外活性(140)，最近显示具有抗WHBV体内活性。PMPA显示了对抑制拉米夫定耐药变异株的活性，并且在体外和临床对多药耐药株有效(28, 80, 338, 348, 365)。

Guanosine analogues

鸟嘌呤核苷类似物

Entecavir: Entecavir, or Baraclude, is a cyclopentyl guanosine analogue. A detailed molecular investigation of the mechanism of inhibition of the viral polymerase activity showed that entecavir triphosphate: (1) inhibits all three steps of viral genome replication, i.e. priming of reverse transcription, minus strand-and plus strand-DNA synthesis; (2) is a competitive inhibitor of the natural dGTP substrate incorporation within nascent viral DNA; (3) binds to the viral polymerase with a high affinity. Furthermore, its template-dependent incorporation in viral DNA in place of deoxyguanosine led to chain termination two or three nucleotides later (298). Studies were performed in the animal models of hepadnavirus replication , including the woodchuck and duck, to gain insight in the in vivo effect of entecavir and the kinetics of viral clearance. First, entecavir was administrated orally in WHV chronically infected woodchucks for 1-3 months in comparison with lamivudine. After 1 month of administration, viremia declined by 3 log 10 copies/mL. At month 3, serum viral load dropped by 7-8 log 10 copies/mL down to 100-1000 copies/mL (113). This was followed by a prolonged study of entecavir administration for 14-36 months which showed a prolonged suppression of viral replication including suppression of viral load, a decline in ccc-DNA levels and expression of viral antigens in the liver of infected animals (62). A delayed emergence of hepatocellular carcinoma was also observed although some animals developed liver cancer despite viral suppression. Studies performed in duck model confirmed these results (103). In vitro studies showed its activity against several multiple drug resistant strains (28, 348). Entecavir resistant mutants have been described; they require a lamivudine resistance mutation backbone to which additional specific entecavir resistance mutants are added (326, 347). These strains remain sensitive to adefovir and tenofovir (347).

恩替卡韦：恩替卡韦或博路定，是一种环戊基鸟嘌呤核苷类似物。对病毒聚合酶活性抑制机制详细的分子研究发现，恩替卡韦三磷酸盐：(1) 能抑制病毒基因组复制的所有三个步骤，即逆转录的启动、负链合成和正链合成；(2) 是天然酶底物dGTP与新生病毒DNA结合的一种竞争性抑制剂；(3) 对病毒聚合酶具有高亲和力。此外，它替代脱氧鸟嘌呤核苷依赖模板与病毒DNA结合，导致2个或3个核苷酸后链终止(298)。通过对肝DNA病毒复制动物模型进行研究，包括土拨鼠和鸭，了解恩替卡韦的体内作用以及病毒清除动力学。治疗开始时，在WHV慢性感染的土拨鼠中，恩替卡韦口服治疗1-3个月，对照组服用拉米夫定。恩替卡韦治疗1个月后，病毒血症减少3 log 10 copies/mL。治疗第3个月时，血清病毒载量下降7-8 log 10 copies/mL，最低达100-1000 copies/mL (113)。随后进行的恩替卡韦治疗14-36个月的长期研究结果显示病毒复制被持久抑制，包括病毒载量减少以及感染动物肝内ccc-DNA水平和病毒抗原表达下降(62)。研究也发现，一些动物尽管病毒得到抑制仍发展成肝癌，但肝癌的出现延迟了。对鸭模型的研究证实了这些结果(103)。体外研究显示恩替卡韦对多重耐药变异株有抗病毒活性(28, 348)。关于恩替卡韦耐药变异株已有描述，它需要在拉米夫定耐药变异基础上额外出现特异性恩替卡韦耐药变异(326, 347)。这些变异株对阿德福韦和替诺福韦仍然敏感(347)。

FLG (2',3’-Dideoxy-3’-Fluoroguanosine) is a synthetic deoxyguanosine analogue originally developed to inhibit HIV replication (137). The functional similarity of the HBV and HIV DNA polymerases has led to the examination of FLG as an inhibitor of human and duck HBV polymerase activity. In vitro, FLG was shown to be an efficient inhibitor of DHBV and HBV replication (294). In contrast to entecavir, FLG inhibits weakly the priming of the reverse transcription, but is a competitive inhibitor of dGTP incorporation and a DNA chain terminator (153). It inhibits similarly the replication of wild-type, lamivudine-resistant, adefovir-resistant, and lamivudine+adefovir resistant HBV mutants (153). In vivo, FLG showed a favorable safety profile and inhibited DHBV replication in DHBV-infected ducks with a significant reduction of serum DHBV DNA levels (215).

FLG（2',3’-双脱氧-3’-氟鸟嘌呤核苷）是一种合成的脱氧鸟嘌呤核苷类似物，最初被用于抑制HIV复制(137)。HBV和HIV DNA多聚酶在功能上具有相似性，从而引发了FLG抑制人和鸭HBV聚合酶活性的研究。体外研究显示，FLG能有效抑制DHBV和 HBV 的复制(294)。与恩替卡韦相反，FLG抑制逆转录启动的能力弱，但却是dGTP结合的竞争性抑制剂和DNA链终止剂(153)。FLG对野生型、拉米夫定耐药、阿德福韦耐药以及拉米夫定+阿德福韦耐药HBV变异株的复制的抑制作用相近 (153)。体内研究显示，FLG安全好，能抑制DHBV感染鸭中DHBV复制，血清DHBV DNA水平显著下降(215)。

Other Molecular Drugs

Beside the nucleoside/nucleotide analogs, a number of other molecules with anti-HBV properties have been discovered and studied in vitro and in animal models.

其他分子药物

　　除了核苷/核苷酸类似物外，体外和动物模型研究中还发现了其他许多具有抗HBV活性的分子。

Antisense Oligodeoxynucleotides: Antisense oligodeoxynucleotides (ODN) are synthetic DNA molecules that can inhibit gene expression within cells by binding to complementary mRNA sequences, thus preventing translation (350). Indeed, use of antisense oligonucleotides specific to the hepadenaviral genome showed its efficacy by stimulation of RNAseH activity and degradation of viral RNA, inhibition of ribosomal assembly, modification of RNA conformation and inactivation of RNA sequences involved in viral replication (169, 257, 349, 351). In the cell culture system, antisense DNA directed to HBV polyadenylation signal (248), and X gene (99) are particularly effective. Korba and Gerin examined the ability of 56 single-strand ODN, which target several HBV specific functions, to inhibit HBV replication in the HepG2.2.15 cell line. The oligomers directed against the HBV encapsidation signal/structure (epsilon) showed the most effective antiviral activity against HBV (168). Similar experiments in DHBV-infected ducks or avian cells in culture yielded promising results (282, 310). ODNs containing unmethylated CpG dinucleotides within specific sequence contexts (CpG motifs) are known as potent activators of the immune system and inducers of several Th1-associated immunomodulatory cytokines. Some results have shown that CpG ODN can inhibit indirectly HBV replication in vitro via activating the immune cells, and could contribute to the development of an immunoregulator against HBV infection (202). Another class of antisense agents, named PNA (peptide nucleic acids), also showed an efficacity against HBV replication by targeting the HBV encapsidation signal (283). Small interference RNA: The transfer of short interfering double-stranded RNA (siRNA), first discovered in C.elegans (100), has proven a powerful tool for interfering with gene expression through a process known as RNA interference. Eventually, this mechanism results in degradation of the respective target RNA (238). Several investigators succeeded in down-regulating HBV RNA and therefore core protein (235, 370), HBe and HBs antigen expression (162) in cell culture or in mice using siRNA or integrating viral vectors expressing shRNA (short hairpin RNA) to prolonge siRNA expression (279).

反义寡脱氧核苷酸：反义寡脱氧核苷酸（ODN）是合成DNA分子，通过与互补mRNA序列结合，能抑制细胞内基因表达，进而阻止翻译(350)。确实，通过刺激RNA酶活性和降解病毒RNA，抑制核蛋白体装配、修饰RNA构象以及与病毒复制有关的RNA序列失活，肝DNA病毒基因组特异的反义寡核苷酸的使用显示了其疗效(169, 257, 349, 351)。在细胞培养系统中，针对HBV多腺苷酸化信号(248)和X基因(99)的反义DNA尤其有效。Korba 和 Gerin检测了56单链ODN的功能，这种ODN针对一些HBV特异性功能，可抑制HepG2.2.15细胞株内HBV复制。这种针对抗HBV衣壳包装信号/结构(ε)的低聚物显示了最有效的抗HBV病毒活性(168)。在DHBV感染鸭或禽类细胞培养中类似的实验得到了相应的结果(282, 310)。已知在特效序列内（CpG基序）含未甲基化CpG二核苷酸的ODNs，是有效的免疫系统活化剂和一些Th1相关免疫调节细胞因子的诱导剂。一些实验结果显示，CpG ODN能够通过激活免疫细胞，间接抑制体外HBV复制，有助于抗HBV感染的免疫调节剂的形成 (202)。另一类名为PNA（肽核酸）的反义物质，通过针对HBV衣壳包装信号，也显示出抗HBV复制能力(283)。小干扰RNA：即双链的短干扰RNA（siRNA）传递，首先在线虫中发现(100)，通过已知的RNA干扰过程，已被证明是干扰基因表达的有力工具。最后，这种机制导致相应的目标RNA 降解(238) 。几位研究者在细胞培养或小鼠中，利用siRNA，或表达shRNA（短发夹RNA）的整合型病毒载体(279)，成功下调了HBV RNA，从而下调了核心蛋白(235, 370)、HBe 和HBs抗原的表达(162)。

Ribozymes: Ribozymes (ribonucleic acid enzymes) are naturally occurring RNA molecules that catalyse RNA sequence-specific cleavage and splicing (96). RNA cleavage specificity is mediated by the ribozyme sequence. The hammerhead and the hairpin ribozymes have been analyzed in a cell culture system. The targeted sequences include poly (A) signal sequence (97), the encapsidation signal in pgRNA (20, 250), the HBc RNA (98, 201, 203), X RNA (118, 203, 357) and HBs RNA (250). Presently a chemically modified ribozyme, targeting HBV mRNA, is at the clinical development stage.

核酶：核酶（核糖核酸酶）是天然存在的RNA分子，可催化RNA序列特异性分裂和剪切(96)。RNA剪切特异性由核酶序列介导。锤头状和发夹结构核酶已在细胞培养系统中被分析。靶序列包括poly (A) 信号序列(97)，pgRNA包装信号(20, 250)，HBc RNA(98, 201, 203), X RNA(118, 203, 357) 和HBs RNA(250)。目前，一种经化学修饰作用于HBV mRNA的核酶，处于临床试验阶段。

Aptamers: Many aptamers are designed to block protein functions. Aptamer, a small nucleotide can bind to its ligand (protein, ion, antibiotic, etc...) with high affinity and high specificity. Their binding is due to their 3-D conformation, there is no sequence complementation between an aptamer and its ligand. Peptide aptamers which specifically bound to the HBV or DHBV core protein have been used in cell culture to inhibit HBV replication by blocking viral capsid formation (34, 331).

适体：许多适体被设计用来阻断蛋白功能。适体，是一种小分子核苷酸，能以高亲和力和高特异性与它的配体（蛋白，离子，抗生素等）结合。这种结合与它们的三维结构有关，适体和其配体间没有互补序列。在细胞培养中，应用能特异性的与HBV 或DHBV核心蛋白结合的肽类适体，可以通过阻断病毒衣壳形成抑制HBV复制(34, 331).。

Peptides: Peptide may be used as a therapeutic antigen by interfering with the interaction between HBV particles and the cell surface or the viral replication and maturation. Recently a myristoylated Pre-S peptide, comprising the pre-S1 region essential for HBV infectivity, efficiently targeted and inactivated a receptor at the hepatocyte surface, preventing HBV infection (122).

多肽：多肽可用作一种治疗用抗原，通过在HBV颗粒和细胞表面相互作用，干扰病毒复制和成熟。最近发现一种含HBV传染性必须的前-S1区十四酰化前-S肽，可以有效的针对和灭活在肝细胞表面的一种受体，防止HBV感染(122)。

HAP (Heteroaryldihydropyrimidines): HAP were discovered as highly potent non-nucleosidic inhibitors of HBV replication in vitro and in vivo (356). HAP, like Bay41-4109 (84) (Table 2) or HAP-1 (317), prevent the proper formation of viral core particles (nucleocapsids) which are the site of viral DNA replication. The clinical efficacy of this treatment modality of HBV infection will now need to be demonstrated.

HAP（异芳基二氢嘧啶类化合物）：体内和体外研究发现，HAP是高效非核苷HBV复制的抑制剂(356)。HAP，如Bay41-4109 (84) (表2) 或者 HAP-1 (317)，防止病毒DNA复制部位病毒核心蛋白（核衣壳）的正确形成。这种治疗方法用于HBV感染的临床疗效目前需要进一步的临床验证。

Chimeric core proteins: The restriction of HBV genome replication to the nucleocapsid makes this nucleoprotein particle an attractive target for intervention. Dominant negative (DN) core protein variants have been shown to interfere with nucleocapsid assembly and to inhibit HBV replication effectively (369).

核心蛋白嵌合体:抑制HBV基因组复制对核衣壳的限制性使得核蛋白颗粒成为干预的显著靶点。研究显示，显性负性核蛋白变异可干扰核衣壳装配，有效抑制HBV复制(369)。

Helioxanthin analogues: Helioxanthin analogues not only inhibit viral DNA synthesis but also decrease the amount of viral RNA and viral protein in HBV-harbouring cells. (51, 204). The detailed mechanism of action of this class of compounds is under further exploration.

赛菊芋黄素类似物：赛菊芋黄素类似物不仅能抑制病毒DNA合成，而且可降低HBV感染细胞的病毒RNA和病毒蛋白(51, 204)，但这类化合物的详细作用机制需要进一步研究。

ER alpha-glucosidase Inhibitors: One function of N-linked glycans is to assist in the folding of glycoproteins by mediating interactions of the lectin-like chaperone proteins calnexin and calreticulin with nascent glycoproteins. These interactions can be prevented with inhibitors of the alpha-glucosidases. Treatment of woodchucks with the N-nonyl-DNJ alpha-glucosidase inhibitor shows a significant decrease of WHV levels, as a result of an inhibition of the endoplasmic reticulum alpha-glucosidases, at concentrations that do not appear to be toxic for the animal (25).

内质网α-糖苷酶抑制剂：N-联聚糖的功能之一是通过介导钙联蛋白和钙网蛋白等类凝集素分子伴侣与新生糖蛋白相互作用，辅助糖蛋白的折叠。α-糖苷酶抑制剂能抑制两者的相互作用。使用N-nonyl-DNJ α-糖苷酶抑制剂治疗土拨鼠肝炎，在未出现动物毒性的浓度下，结果显示由于内质网α-糖苷酶的抑制，能显著降低WHV水平 (25)。

Single chain antibody: Studies using cloned single chain Fv (sFv) fragment directed against HBsAg or HBV pre-S1 showed that this antibody fragment could reduce extracellular HBsAg or have a high neutralizing activity against pre-S1 or HBV virion binding to liver cell line (263).

单链抗体：关于采用克隆单链Fv（sFv）片段直接抑制HBsAg 或者 HBV pre-S1的研究显示，该单链抗体片段能减少细胞外HBsAg，或者针对前S1或结合到肝细胞系的HBV病毒颗粒有较高的中和活性(263)。

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抗病毒治疗

Review Article: Lok ASF, McMahon BJ. Chronic Hepatitis B. AASLD Practice Guidelines. Hepatology 2007:45;507-539.

Review Article: Keeffe EB, et al. A Treatment Algorithm for the Management of Chronic Hepatitis B Virus Infection in the United States: 2008 Update. Clin Gastroenterol Hepatol. 2008;6:1315-1341.

Hepatitis B virus infection can be acute or chronic, asymptomatic to fatal. Most acute HBV infections clear completely and leave no evidence of long-term hepatic injury. Therefore the primary target for antiviral therapy is chronic infection. The main aims of antiviral therapy are to clear the replicating virus and thereby, if administered early enough in the disease process, to prevent or delay the development of life-threatening complications. Several studies have shown that patients who lose HBV DNA and seroconvert HBeAg, with eventual loss of hepatitis surface antigen (HBsAg), in response to therapy have improved clinical outcomes.

　　乙肝病毒感染可能表现为急性或慢性，从无临床症状到死亡。大部分急性HBV感染可完全清除，无长期肝损害证据。因而抗病毒治疗主要针对慢性感染。抗病毒治疗的主要目标是清除复制病毒，因而如果能够在疾病早期予以治疗，能够防止或延缓致死性并发症。一些研究显示，治疗应答患者，HBV DNA消失，HBeAg血清转换，最终乙肝表面抗原（HBsAg）消失，能改善临床预后。

Many agents, belonging to different classes of antiviral therapeutics (e. g. immunomodulators and HBV DNA polymerase inhibitors), have been evaluated for the treatment of chronic hepatitis B. Most have been found to be ineffective or too toxic at effective doses in vivo. Others are still under evaluation (Table 2). Six therapeutic agents have been approved by the FDA and are currently licensed as therapy in several countries worldwide: standard and pegylated interferon-alpha 2a, lamivudine, adefovir dipivoxil, entecavir and telbivudine (379).

　　许多不同类型的抗病毒药物（如免疫调节剂和HBV DNA聚合酶抑制剂）对于慢性乙肝的治疗作用已经被评估。体内研究显示，大多数抗病毒药物无效或有效剂量毒性太大。而其它作用仍在评估中(表2)。六种治疗药物经FDA批准，现已在全世界一些国家被批准用于治疗，包括：普通干扰素和聚乙二醇干扰素-α2a，拉米夫定，阿德福韦酯，恩替卡韦和替比夫定(379)。

Interferon-alpha (standard and pegylated)

干扰素-α（普通和聚乙二醇）

Interferon-alpha (IFN-alpha) belongs to a family of natural occurring proteins that have antiviral and immunomodulatory actions. They bind to cellular receptors and activate secondary messengers so as to initiate production of multiple proteins critical to the defense of the cell against viruses (141). The antiviral effects include degradation of viral mRNA, inhibition of viral protein synthesis, and prevention of the viral infection of cells. The immunomodulating effects include enhancement of foreign antigen presentation by HLA I and II to the immune system, activation of natural killer (NK) cells and other immune cells, and increased cytokine production. IFN-alpha is obtained by two main methods. It can be either purified from human lymphoblastoid cells, which have been stimulated by Sendai virus or produced using recombinant molecular biology in Esherichia coli. In the later case, the gene encoding for one of the human subtypes (beta-2a or beta-2b) of interferon is cloned into bacterial expression vector and used for the production.

　　干扰素-α（IFN-α）属于一类天然蛋白质，具有抗病毒和免疫调节作用。它们与细胞受体结合，激活第二信使，产生大量细胞防御病毒的关键蛋白质(141)。抗病毒作用包括病毒mRNA降解，抑制病毒蛋白合成和防止病毒感染细胞。免疫调节作用包括免疫系统HLA Ⅰ和HLA Ⅱ类外来抗原呈递增加，自然杀伤（NK）细胞和其它免疫细胞的激活，以及细胞因子产生增加。IFN-α通过两种主要方法获得。它可从仙台病毒刺激的人淋巴母细胞中提纯制备而得，或在大肠杆菌中采用重组分子生物学技术产生。后者，对干扰素人类亚型（β-2a或β-2b）其中之一进行基因编码，克隆入细菌表达载体，用于生产。

Standard interferon

普通干扰素

Efficacy: The efficacy of both lymphoblastoid and recombinant IFN-alpha for the treatment of chronic hepatitis B has been demonstrated in numerous placebo-controlled trials (2, 14, 27, 146, 217, 233, 268, 269, 284, 360). The dose and duration of IFN-alpha treatment varied in these studies. The dose of IFN-alpha ranged from 1 to 10 million units daily or three times weekly for 3 to 6 months. Patients were usually followed for 6 to 12 months after completion of interferon therapy. The best-designed studies were summarized in several meta-analysis (68). In average, a four-month course of treatment results in a 25-40% virological response with significant reduction of serum HBV DNA concentration, normalization of ALT level, and loss of HBeAg. Seroconversion to anti-HBe positively occurs in 19-34%. The data show that a high dose of IFN-alpha is more effective than a low dose, and the 3-to 4-month interferon treatment protocol is as effective as 6 months of therapy (362). In 60-70% of responders, approximately 2 months after the onset of treatment, a rise in ALT level is observed, which is thought to reflect the immune-mediated clearance of HBV-infected hepatocytes. This level returns to normal as HBV DNA or HBeAg is cleared. In nonresponders, such changes are not normally observed. The intensity of this are seldom aggravates the underlying liver status. Indeed, if there is a striking increase in ALT, a rise in bilirubin, or new signs or symptoms of hepatic decompensation, then the IFN-alpha therapy should be reduced or withheld and the patient should be closely followed.

疗效：类淋巴母细胞产生和重组的IFN-α治疗慢性乙型肝炎的疗效已在大量安慰剂对照试验中证实(2, 14, 27, 146, 217, 233, 268, 269, 284, 360)。各研究IFN-α的治疗剂量和疗程不尽相同。IFN-α治疗剂量从1-10MU，每日一次或每周三次，疗程3-6个月。患者完成IFN治疗后，通常随访6-12个月。一些荟萃分析已对良好设计的研究进行总结(68)。平均治疗4个月，25-40%患者发生病毒学应答，表现为血清HBV DNA浓度显著下降，ALT水平复常，HBeAg消失。19-34%的患者发生血清转换，抗HBe阳性。资料显示，大剂量IFN-α治疗比小剂量IFN-α更有效，IFN治疗3-4个月与治疗6个月疗效相当(362)。60-70%的治疗应答者，治疗开始后大约2个月，可观察到ALT水平升高，被认为是HBV感染肝细胞免疫清除的反应。当HBV DNA或HBeAg被清除后，ALT水平恢复正常。治疗无应答者，这种改变不常见。该作用强度很导致基础肝病加重。确实，如果ALT显著增加，胆红素升高，或出现新的肝功能失代偿的症状或体征，IFN-α治疗应减量或停止，患者应该密切随访。

Indications: Patients with chronic hepatitis who present an increased serum ALT level for more than 6 months and have serologic evidence of active viral replication should be considered for interferon therapy provided they have no contraindications that exclude them from therapy (117). The main contraindications are summarized in Table 3.

适应症：慢性肝炎患者出现ALT血清水平升高，持续时间超过6个月，存在病毒复制活跃的血清学证据，如无治疗禁忌症，应该考虑予以IFN治疗(117)。主要禁忌症见表 3。

Dosage: The recommended dose of IFN-alpha is a daily injection of 5 million international units (5 MU) or a thrice-weekly injection of 9-10 MU (329, 362), self-injected, subcutaneously for 16 weeks. A monitoring of a complete blood count, prothrombin time, total bilirubin, ALT, AST, HBsAg, anti-HBs, HBeAg, anti-HBe, and quantitative HBV DNA should be done at 2, 4, 8, 12, and 16 weeks.

剂量：IFN-α推荐剂量是5百万国际单位（5MU），每日一次，或者9-10MU(329, 362)，每周三次，皮下注射，疗程16周。患者在治疗后的第2，4，8，12和16周应监测血常规，凝血酶原时间，总胆红素，ALT，AST，HBsAg，抗HBs，HBeAg, 抗HBe和HBV DNA定量。

Prognosis for interferon therapy and adverse effects are detailed below.

IFN治疗预后和副作用详见后面。

Pegylated interferon

聚乙二醇IFN

Standard, unpegylated interferons exhibit rapid onset of activity, short half-lives, and rapid renal clearance, when administrated subcutaneously in typical dosing regimens. Because unpegylated interferons display substantial peaks and troughs in their serum concentrations, they are ideal molecules to undergo pegylation modification (267). Pegylation is the attachment of a polyethylene glycol (PEG) moiety to a molecule to slow the renal elimination and improve tissue drug distribution, thereby enhancing clinical activity of the therapeutic agent (267, 376).

　　标准剂量普通、非聚乙二醇IFN皮下注射给药后，表现为起效快，半衰期短，肾清除快。由于非聚乙二醇IFN在其血清浓度上存在峰值和谷值，因而是接受聚乙二醇化修饰的理想分子(267)。聚乙二醇化是将聚乙二醇（PEG）部分与分子结合，可延缓肾脏清除，改善组织药物分布，从而增强治疗药物的临床疗效(267, 376)。

Efficacy: The efficacy of PEG IFNs has been recently assessed in the treatment of chronic hepatitis B. A first randomized controlled study of PEG IFN alpha 2a has been performed in patients with HbeAg-positive chronic hepatitis B (67). Treatment duration and follow-up were each 24 weeks. At the end of follow-up, treatment response defined by loss of HbeAg with serum HBV DNA level below 500 000 copies/mL with normal ALT was observed in 19-28% of patients receiving PEG IFN alpha 2a (at a dose of 90 µg, 180 µg or 271 µg per week) versus 12% of patients who received standard IFN 2a. This study does not prove the superiority of PEG IFN alpha 2a as compared with standard IFN 2a particularly since the dose of IFN 2a used was relatively low (4.5 million units, three times a week). However a retrospective analysis showed that the rates of response were higher with PEG IFN for the patients who were the most difficult to treat (with high HBV DNA level or low ALT levels) (187). Therefore this study strongly suggests that PEG IFN alpha 2a is more effective than standard IFN 2a for the treatment of chronic hepatitis B. Several large randomized controlled trial have clearly confirmed the efficacy of PEG IFN alpha 2a or 2b for the treatment of HBe Ag-positive or negative chronic hepatitis B (155, 187, 224).

疗效：PEG IFNs治疗慢性乙肝的疗效近来已被评估。PEG IFN α-2a的首项随机对照研究在HBeAg阳性的慢性乙肝患者中进行(67)。治疗时间和随访时间分别为24周。在随访结束时，治疗应答定义为HBeAg转阴，血清HBV DNA水平<500000copies/mL，ALT正常，PEG IFN α-2a治疗患者（每周90µg, 180µg或271µg）19-28%发生应答，而对照的普通IFN 2a治疗患者应答率为12%。由于IFN 2a治疗使用剂量相对较小（4.5MU，每周三次），较标准IFN 2a相比，该研究并未显示PEG IFN α-2a的显著优势。然而，一项回顾性分析显示，在最难治疗的患者（HBV DNA高水平，或ALT低水平）中，PEG IFN治疗患者应答率较高(187)。因此，该研究有力地提示，PEG IFN α-2a较普通IFN 2a治疗慢性乙肝更有效。几项大规模的随机对照试验已明确证实了PEG IFN α-2a或2b治疗HBeAg阳性或阴性慢性乙肝患者的疗效(155, 187, 224)。

Prognosis and indications for interferon therapy: Favorable prognostic indices for a successful outcome with standard or pegylated IFN-alpha therapy have been evaluated and are listed in Table 4. These indicators do not provide an absolute guarantee of success with interferon therapy, but suggest a higher likelihood of success and may assist in patient selection for interferon therapy. A low concentration of HBV DNA and a raised ALT level are the best indices of predicting a successful treatment outcome (59, 255, 329, 362). One study suggested that genotypes A and B infected patients responded better than those infected by genotypes D and C respectively, in terms of HBeAg seroconversion and HBsAg loss (155).

IFN治疗预后和适应症：普通或聚乙二醇IFN-α治疗成功的有利预后指标已被评估，见表 4。这些指标并不能绝对保证IFN治疗成功，但能提示治疗成功较高的可能性，有助于选择患者进行IFN治疗。HBV DNA低水平和ALT水平升高是预测治疗成功的最佳指标(59, 255, 329, 362)。一项研究显示，基因型A和B感染患者，较基因型D和基因型C感染患者更容易发生HBeAg血清转换和HBsAg转阴(155)。

Dosage: The recommended prescription for PEG IFN alpha 2a is once-weekly subcutaneous administration at 180 µg for 48 weeks.

剂量：PEG IFN α-2a推荐剂量为180µg，每周一次，皮下注射，疗程48周。

Adverse effects: Side effects associated with PEG IFN were comparable to those observed with standard interferon (67). They both have numerous adverse effects that tend to be dose dependent. Flu-like symptoms, fevers, rigors, fatigue, myalgia, arthralgia, and headaches are very common immediately after injection, but are more frequent with pegylated than with standard IFN. Acetaminophen (or nonsteroidal anti-inflammatory drugs) helps relieve these symptoms, and these early adverse effects tend to subside or improve after the first or second week of treatment. A reduction of the count of the platelets and/or white cells also often occurs and requires a modification of the dosage. A granulocyte count of < 7.5 × 108/L or a platelet count < 4 × 1010/L necessitates cessation of therapy. A reversible moderate alopecia can manifest as well as depression with insomnia or an inability to concentrate. Hypnotics and mild anti-depressants may be required. Weight loss, impotence and vitreous hemorrhages have also been noted to occur. About 50% of patients receiving IFN-alpha therapy for 16 weeks or longer develop antinuclear antibodies, smooth muscle antibodies, and thyroid antibodies. Autoimmune disorders such as thrombocytopenic purpura, hemolytic anemia, vasculitis, or type-1 diabetes can manifest. These usually resolve after the cessation of interferon therapy. However, about 3% of patients receiving IFN-alpha develop a permanent hypothyroid state requiring lifelong thyroid replacement therapy. In all cases, a close monitoring and supervision are necessary during treatment.

副作用：PEG IFN引起的副作用与普通IFN相当(67)。两者副作用多，且存在剂量依赖性趋势。皮下注射后即刻出现的流感样症状，发热，寒战，乏力，肌痛，关节痛和头痛十分常见，PEG IFN较普通IFN更频繁。扑热息痛（或非甾体抗炎药物）可帮助减轻症状。这些早期副作用在患者在治疗第一周或第二周后，会渐消退或好转。血小板数和/或白细胞数减少也常见，需要调整治疗剂量。粒细胞数< 7.5 × 10⁸/L，或血小板数< 4 × 10¹⁰/L，需要停止治疗。除了中度可逆性脱发，还会有抑郁伴失眠或注意力难以集中外。可能需要安眠药和轻效抗抑郁药治疗。体重下降，性无能和玻璃体出血也值得注意。大约50%的患者IFN-α治疗16周或更长时间后出现抗核抗体，平滑肌抗体和甲状腺抗体。可能出现血小板减少性紫癜，溶血性贫血，血管炎或1型糖尿病等自身免疫性疾病。这些情况一般停止IFN治疗后可改善。然而，大约3%的患者接受IFN-α治疗出现永久的甲状腺功能减退，需要甲状腺素终身替代治疗。所有患者，在治疗期间需要密切监测和管理。

(Printable Version of Interferon-alpha for Hepatitis B Virus)

Alternative Therapy: Nucleoside/Nucleotide Analogs

替代治疗：核苷/核苷酸类似物

Many nucleoside/ nucleotide analogues, which are inhibitors of the HBV DNA polymerase (reverse transcriptase), have been evaluated for the treatment of HBV infection. Since 1998 four of them are FDA approved and used in clinical practice: lamivudine FDA-approved in 1998, adefovir dipivoxil in 2002, entecavir in 2005, and telbivudine in 2006. Some, like the tenofovir, or emtricitabine are still under evaluation (Table 2). After the tragedy that occurred during the clinical evaluation of the fialuridine (FIAU), which caused the death of patients because of mitochondrial toxicity (70, 71, 200, 234), more vigilance was necessary. For instance, and despite promising results obtained in early phase I/II clinical trials, studies on famciclovir (penciclovir) and lobucavir have been stopped because of efficacy and toxicity (e. g. development of hepatocellular carcinomas in rats) problems respectively.

　　大多数核苷/核苷酸类似物，都是HBV DNA多聚酶抑制剂（逆转录酶），用于HBV感染的治疗已经被评估。自1998年来，其中四种药物经FDA批准用于临床，即拉米夫定（1998年经FDA批准），阿德福韦酯（2002年），恩替卡韦（2005年），替必夫定（2006年）。有些药物入替诺福韦、恩曲他滨等仍在评估中(表2)。在非阿尿苷（FIAU）临床评估期间，因线粒体毒性引致患者死亡(70, 71, 200, 234)，自该悲剧后，需要引起更多警戒。例如，泛昔洛韦（喷昔洛韦）和洛布卡韦的研究虽然在早期I/II期临床试验中获得较好的结果，但分别因为其疗效和毒性问题（如小鼠中肝细胞癌形成），被停止使用。

Lamivudine

拉米夫定

Efficacy: The efficacy and safety of lamivudine for the treatment of chronic hepatitis B has been demonstrated in numerous placebo-controlled trials (86-88, 174, 175, 253). Lamivudine administration at a daily dose of 100mg is associated with a significant drop of HBV DNA (3-log decrease), HBeAg, and HBsAg in the serum of virtually all patients treated, including those who did not respond to IFN-alpha. During phase III placebo-controlled trials, including more than 600 patients with HBeAg and elevated transaminases (88, 175), a course of 12 months of lamivudine therapy resulted in i) decrease of HBV DNA to undetectable level in most of the patients, ii) anti-HBe seroconversion in 16 to 17 % of the patients compared with 4 to 6 % in the placebo groups, iii) a normalization of serum ALT level in 41 to 72% versus 7 to 24% in the placebo groups, and liver histology improvement in 52 to 56% of the patients versus 25% in the placebo group (Table 5).

疗效：拉米夫定用于治疗慢性乙肝的疗效和安全性已在大量安慰剂对照试验中被证实(86-88, 174, 175, 253)。事实上在所有治疗患者中，包括对IFN-α治疗无应答的患者，口服拉米夫定，100mg/d，会带来显著的血清HBV DNA（下降3-log），HBeAg和HBsAg下降。III期安慰剂对照试验期间，超过600例HBeAg阳性和转氨酶升高的患者入组研究(88, 175)，拉米夫定治疗12个月的结果：i）大部分患者HBV DNA下降至不可检测水平，ii）治疗组患者发生抗HBe血清转换达16-17%，，而对照的安慰剂组4-6%iii）治疗组患者血清ALT水平正常达41-72%，而安慰剂组为7-24%，肝组织学改善治疗组患者达52-56%，而安慰剂组为25% (表 5)。

However, viral breakthrough, due to the apparition of a lamivudine-resistant variant (see below), was observed from the 6th month of therapy and became progressively more frequent until the end of 12 months therapy where it reached 14% to 32% of the patients (88, 175).

　　然而，由于拉米夫定耐药株的出现，治疗第6个月检测到病毒突破，且发生率逐渐增加，至12个月治疗结束时达到14%-32%(88, 175)。

The effect of extended lamivudine therapy was analyzed in subgroups of patients who were initially enrolled in the 12 months course of lamivudine (88, 175, 186, 198, 207). An increase in anti-HBe seroconversion rate was observed over time: 17-22% at 1 year, 27-29% at 2 years, and 40% at 3 years. This suggests that long-term lamivudine therapy is required in the majority of the patients to obtain anti-HBe seroconversion. However, the incidence of viral breakthrough increases as well with the length of the treatment (Figure 4), indicating that lamivudine should be used with caution (see "resistance of HBV to lamivudine" section).

　　最初入组拉米夫定治疗12个月的患者被分为亚组，进一步分析延长拉米夫定疗程效果。发现抗HBe血清转换率随时间增加：第1年17-22%，第2年27-29%，第3年40%。该结果提示大部分患者需要长期拉米夫定治疗以获得抗HBe血清转换。然而，病毒突破发生率也随治疗时间延长而增加(图 4)，提示应慎重应用拉米夫定（见“HBV拉米夫定耐药”部分）。

Lamivudine-induced anti-HBe seroconversion is usually durable provided that the treatment lasts at least 6 month after the onset of seroconversion. For instance, in an Asian study (309) it was shown that HBeAg seroconversion was not durable in endemic areas of HBV infection, with anti-HBe loss in 37.5% and 49.2% at 1 year and 2 years of follow-up respectively, and reappearance of HBeAg in 81% and elevation of serum ALT in 94% of these relapsers. However, in this Korean study, lamivudine was discontinued 2 to 4 months after HBeAg disappearance. As the duration of additional lamivudine therapy after HBeAg seroconversion was one independent predictive factor for post-treatment relapse, it is therefore suggested to maintain antiviral treatment for at least 6 months after anti-HBe seroconversion.

　　如果拉米夫定引起抗HBe血清转换后持续治疗至少6个月，该血清转换通常持久。例如，一项亚洲研究(309)显示，HBeAg血清转换在HBV感染流行区域并不持久，随访1年和2年，分别有37.5%和49.2%的患者抗HBe消失，其中81%HBeAg重新出现，94%血清ALT升高。然而，在这个韩国研究中，拉米夫定在HBeAg消失后2-4个月就停药了。由于HBeAg发生血清转换后继续拉米夫定治疗的持续时间是治疗后复发的独立预测因子，因而提示在抗HBe发生血清转换后，须维持抗病毒治疗至少6个月。

Moreover, few studies showed that the risk of relapse after anti-HBe seroconversion is minimal when both serum HBV DNA level decreases below 104 copies/ml and no pre-core mutant is selected. This suggests that monitoring of antiviral therapy should rely on quantitative and sensitive assays for HBV DNA detection and mutant detection assays.

　　此外，少数研究显示，当血清HBV DNA水平下降至10⁴copies/ml以下，且未发生前C区变异时，抗HBe血清转换后复发的风险最小。这提示，抗病毒治疗监测应根据HBV DNA定量检测的敏感性试验和变异检测分析。

Prognosis For Lamivudine: Studies have shown that patients with pre-therapy ALT level higher than 5 times the normal had a much higher anti-HBe seroconversion rate up to 65% at 1 year (52, 290) and 80% at two years (207), suggesting that lamivudine is more effective in patients who have mounted an ongoing endogenous immune response to HBV. Among patients with level of ALT higher than two times the normal, anti-HBe seroconversion increases from 17-22% to 37.5-38% at year one, 27-29% to 42-47.5% at year two, and 40% to 65% at year three (52, 198, 207). Moreover anti-HBe seroconversion is sustained in approximately 75% of these patients. This also indicates that anti-HBe seroconversion is unlikely in patients with normal ALT level at baseline.

拉米夫定预后：研究显示，患者治疗前ALT水平高于5倍正常值，抗HBe血清转换率更高，第1年达65% (52, 290)，第2年达80%(207)，提示在已存在HBV内源性免疫应答的患者中，拉米夫定治疗疗效更好。在ALT水平高于2倍正常值患者中，抗HBe血清转换率第1年从17-22%增加到37.5-38%，第2年从27-29%增加到42-47.5%，第3年从40%增加到65% (52, 198, 207)。此外，这些患者中大约75%持续抗HBe血清转换。这也提示基线ALT水平正常患者不太可能发生抗HBe血清转换。

Indications: Patients with chronic hepatitis who present an increased serum ALT for more than 6 months and have serologic evidence of active viral replication, in particular high HBV DNA level which represents an unfavorable situation for IFN-alpha treatment, may be treated by lamivudine. Patient selection is not influenced by factors such age, ethnicity, hepatic function, prior IFN-alpha therapy, or the presence of pre-core mutant HBV (87, 175, 291, 325, 367). Lamivudine is also effective at suppressing HBV replication both before and after liver transplantation (121, 271, 272), and provides clinical benefit to those with liver decompensation (312, 341, 345).

适应症：慢性肝炎患者，持续血清ALT水平升高超过6个月，存在病毒活跃复制的血清学证据，尤其是HBV DNA高水平，提示不利于IFN-α治疗，可以使用拉米夫定治疗。治疗患者不受年龄，种族，肝功能，既往IFN-α治疗或HBV前C区变异等因素的影响(87, 175, 291, 325, 367)。拉米夫定也能在肝移植前后有效抑制HBV复制(121, 271, 272)，并使肝功能失代偿患者临床收益(312, 341, 345)。

Dosage: The recommended dose of lamivudine is 100 mg per day. From the results of clinical trials, mathematical models were applied to determine the kinetics of viral clearance. These studies demonstrated that long-term lamivudine treatment is required to control or eradicate HBV infection (256). The antiviral treatment should be maintain for at least 6 months after anti-HBe seroconversion to prevent relapse. Then, this places the patient at risk of developing resistance to lamivudine by the selection of polymerase mutants that are resistant to this nucleoside analog (386). It remains therefore to determine the risk-benefit for those patients who failed to seroconvert and require long-term treatment.

剂量：拉米夫定推荐剂量为每日100mg。根据临床结果，运用数学模型计算清除病毒动力学。研究证实显示，控制或消除HBV感染需要长期拉米夫定治疗(256)。抗HBe血清转换后为防止复发，应维持至少6个月抗病毒治疗。然而，在这种情况下，一些患者中由于针对核苷类似物的选择性多聚合酶区突变有发生拉米夫定耐药风险（386)。因此，对未能血清转换需要长期治疗患者的风险-效益仍有待明确。

Adverse Effects: Lamivudine is well tolerated in most patients (291). Its safety has been established in four international, multicentre, controlled phase III trials that included 967 patients among whose 558 received lamivudine at 100 mg/day (175, 290). In these studies, patient age, sex, presumed route of infection, and the presence or absence of cirrhosis had no influence on the incidence of adverse reactions. Adverse effects were mild and included headache, nausea, gastrointestinal upset, musculoskeletal discomfort fatigue, and slight increase of serum amylase. Moreover, liver enzyme elevations and heamatological toxicity did not differ significantly in patients receiving lamivudine or placebo. In contrast to IFN-alpha, lamivudine was associated with only modest, asymptomatic, and transient ALT elevations during treatment. In lamivudine treated patients, 20% of patients with an ALT elevation exhibited HBeAg seroconversion, in contrast to 10% of placebo-treated patients, indicating that in these cases, ALT are likely was the reflect of the anti-HBV immune response. No increase in clinically significant post-treatment ALT exacerbation was noted in patients receiving lamivudine by comparison with the other treatment groups. Very importantly, no mitochondrial toxicity was observed in prolonged use (144).

副作用：大部分患者拉米夫定耐受性好(291)。它的安全性已在四项国际、多中心、III期对照试验中被证实，共有967例患者入组研究，其中558例患者接受100mg/日的拉米夫定治疗(175, 290)。这些研究中，患者年龄，性别，可能的感染途径，以及是否存在肝硬化，与副作用的发生率无关。拉米夫定副作用轻微，包括头痛，恶心，胃肠不适，肌与骨骼疲劳，以及血清淀粉酶轻度升高。此外，肝脏酶学升高和血液毒性在拉米夫定治疗患者或安慰剂治疗患者间无显著不同。与IFN-α治疗相比，拉米夫定治疗期间仅伴有中度、无症状的、一过性ALT升高。拉米夫定治疗患者中，20%ALT升高患者出现HBeAg血清转换，而安慰剂治疗组患者为10%，提示患者ALT可能反映抗HBV免疫应答。与其它治疗患者相比，患者接受拉米夫定治疗后未观察到ALT临床显著急剧增加。十分重要的是，拉米夫定长期治疗未发现线粒体毒性(144)。

Resistance of HBV to Lamivudine: Development of mutants resistant to effective antiviral agent is a significant concern. As previously observed for HIV and anticipated in in vitro studies, HBV develops resistance to lamivudine. Results of clinical trials and cohort studies have shown that approximately 20% of patients develop lamivudine resistance each year ; a plateau of 70% of patients with resistance is reached after 4 years of therapy (176, 216, 383) (Figure 4), suggesting that approximately 30% of patients present a long term response to lamivudine. The main polymerase gene mutations conferring resistance to lamivudine have been characterized by in vitro phenotypic studies. Main lamivudine resistance mutants harbor a M204V or I substitution in the YMDD motif of the C domain of the reverse transcriptase domain (3) (Figure 3). It has been hypothesized that these mutations affect lamivudine triphosphate efficacy by a mechanism of steric hindrance in the cataclytic site of the viral enzyme (16, 74). As these substitutions affect the enzymatic activity and the replication capacity, compensatory mutations restoring some levels of replication capacity have been described, i.e. V173L and L180M (3, 81). After lamivudine cessation the wild-type virus tends to re-emerge (290). Recently, lamivudine failure was also associated to the emergence of A181V and A181T mutations in reverse transcriptase (114, 368)

拉米夫定HBV耐药：对有效的抗病毒药物发生耐药变异是一个值得关注的问题。与既往HIV治疗发现以及体外试验预计一样，HBV发生拉米夫定耐药。临床试验和队列研究的结果显示，每年大约有20%的患者发生拉米夫定耐药；治疗4年后，患者拉米夫定耐药率达70%，进入平台期(176, 216, 383) (图 4)，提示大约30%的患者拉米夫定长期有效。通过体外表型研究已经确定了导致拉米夫定耐药主要聚合酶基因变异。拉米夫定主要变异位于逆转录酶C区YMDD基序M204V或M204I替代(3) (图 3)。这些变异被认为通过病毒酶催化部位的空间位阻机制，影响了拉米夫定三磷酸盐有效性(16, 74)。由于这种替代影响了酶活性和复制能力时，发现存在补偿变异，如V173L和L180M(3, 81)，在一定程度上恢复一些复制能力。停止拉米夫定治疗后，野生型病毒趋向与重新出现(290)。近来，拉米夫定治疗失败也与逆转录酶区A181V和A181T变异出现有关(114, 368)。

The management of patients with YMDD variants is challenging, but some nucleoside analogues proved their efficay on lamivudine-resistant variants. The susceptibility of lamivudine-resistant HBV to eleven nucleoside analogues in various stages of clinical development was assessed (104, 259). The results of these studies indicate that lamivudine-resistant HBV remain sensitive to acyclic phosphonate nucleotides (adefovir, tenofovir, and alamifovir), have reduced susceptibility to entecavir, and have high-level cross-resistance to all L-nucleosides tested including emtricitabine, telbivudine, clevudine, and torcitabine. These findings are of clinical relevance for the management of antiviral treatment failure in patients and the future design of new combination therapy trials.

　　YMDD变异患者的治疗具有挑战性，但一些核苷类似物已被证实治疗拉米夫定耐药患者有效。拉米夫定耐药HBV对11种核苷类似物的敏感性，已在不同临床阶段中被评估(104, 259)。研究结果提示，拉米夫定耐药HBV对无环核苷酸膦酸脂类化合物（阿德福韦，替诺福韦和阿拉福韦）仍然敏感，对恩替卡韦的敏感性下降，经检测与所有L-核苷类有高水平交叉耐药，包括恩曲他滨，替比夫定，克拉夫定和托西他滨。该结果对抗病毒治疗失败患者的管理和将来新的联合治疗试验设计有重要的临床应用价值。

Indeed, clinical relapse may occur in individuals who develop a significant population of YMDD variants during treatment and may be associated with a deterioration of liver disease (205). However, in most patients with YMDD variants serum ALT and HBV DNA remain below baseline values initially when lamivudine therapy is continued. In these patient the likelihood of the progression of liver disease is reduced on the shirt term (366). Moreover, in the Liaw et al . (205) study, it was observed that 27% of these YMDD-variant-carrier patients achieved anti-HBe seroconversion. Recently long term data showed that lamivudine resistance is associated with the progression of liver disease (208). These data suggest that antiviral therapy should be modified as soon as viral breakthrough is detected, to prevent disease progression (182, 379).

　　确实，治疗期间YMDD变异病毒株发展到显著数量时患者可出现临床复发，并可伴有肝病恶化(205)。然而，大部分YMDD变异患者，继续拉米夫定治疗，血清ALT和HBV DNA仍低于最初的基线值。患者肝病进展的可能性在短期内下降(366)。此外，Liaw等研究(205)发现，27%的YMDD变异携带者可获得抗HBe血清转换。近来，长期研究资料显示，拉米夫定耐药和肝病进展相关(208)。一旦检测到病毒突破，需要调整抗病毒治疗，以防止疾病进展(182, 379)。

Lamivudine-resistant mutants occur more frequently and rapidly in patients receiving lamivudine to suppress HBV in liver transplantation than in those receiving lamivudine for chronic HBV.

　　接受拉米夫定抑制HBV的肝移植患者，同拉米夫定治疗的慢性HBV感染者相比，拉米夫定耐药变异发生率更高更快。

Adefovir Dipivoxil

阿德福韦酯

Efficacy: Adefovir dipivoxil (bis-POM PMEA) is broad-spectrum antiviral nucleoside analogue that is active against HBV and HIV, by acting as chain terminator. A large randomized, placebo-controlled study enrolled 515 Hbe Ag-positive patients randomized to receive adefovir dipivoxil 10 mg daily (n=172), adefovir 30 mg daily (n=173), or placebo (n=170) for 48 weeks (223). There was a rapid decrease in the median serum HBV DNA level in patients treated with adefovir dipivoxil, with statistically significant differences with placebo (Table 6). At week 48, the median change from baseline in serum HBV DNA was -3.5 log10 for adefovir (10 mg) compared with -0.5 log10 copies/mL for placebo. Significantly more patients had undetectable serum HBV DNA levels (below 400 copies/mL) (21% vs 0%), (P<0.001). HbeAg seroconversion was observed in 12% of the patients receiving adefovir 10 mg compared with 6% in the placebo group (p<0.05). ALT normalization was achieved in 48% compared with 16% (p<0.001). A significantly higher proportion of patients receiving adefovir 10 mg showed improvement in liver histology at week 48 compared with those receiving placebo (53% versus 25%; p<0.001). A recent study on 480 chineese subjects confirmed the safety and effectiveness of adefovir to treat HBeAg positive CHB patients. This study is continuing for an additional 4 years (375). These results were confirmed in HBe Ag-negative patients during a 240 weeks extended period, with an improvement of liver histology which was correlated with the control of viral load (129-131).

疗效：阿德福韦酯（bis-POM PMEA）是一种广谱的核苷类似物，作为链终止剂发挥作用，具有抗HBV和HIV的活性。一项大规模随机安慰剂对照研究中，515例HBeAg阳性患者入组研究，随机接受阿德福韦酯10mg/d（n=172），阿德福韦酯30mg/d（n=173），或安慰剂（n=170）治疗 48周(223)。阿德福韦酯治疗患者平均血清HBV DNA水平快速下降，较安慰剂组患者存在显著的统计学差异(表6)。治疗第48周，阿德福韦酯（10mg）治疗组平均血清HBV DNA水平下降3.5 log10copies/mL，而安慰剂治疗组较基线下降0.5 log10 copies/mL。明显更多患者血清HBV DNA水平下降至检测不到的水平（<400 copies/mL）（21%/0%，P<0.001)。较安慰剂组6%的患者HBeAg血清转换相比，阿德福韦酯10mg治疗组12%的患者发生HBeAg血清转换（p<0.05）。两组患者ALT恢复正常分别占48%和16%（P<0.001）。治疗第48周，较安慰剂组患者相比，更多阿德福韦酯10mg治疗组患者出现肝组织学改善（53%/25%; p<0.001）。近来一项480例中国受试者的研究证实了阿德福韦酯治疗HBeAg阳性CHB患者的安全性和有效性。该研究正在继续附加的4年(375)。这些结果证实，HBeAg患者在240周长期治疗中，伴有肝组织学改善，这与控制制病毒载量有关(129-131)。

The efficacy and safety of adding adefovir to lamivudine in patients with YMDD mutants were also tested. Clinical trials to date show that virological and biochemical improvement are observed (273) (Table 6), and that early add-on therapy is recommended in patients with lamivudine resistance. Moreover, virological breakthrough was observed in 21% of patients treated with adefovir monotherapy during 18 months following lamivudine failure against 0% of patients treated with lamivudine+adefovir therapy (277).

　　拉米夫定治疗发生YMDD变异患者，加用阿德福韦酯治疗的安全性和有效性也被评估。临床试验资料显示，患者可出现病毒学和生化学改善(273) (表6)，拉米夫定耐药患者推荐早期加药治疗。另外，拉米夫定治疗失败后，阿德福韦酯单药治疗18个月，21%的患者发生病毒学突破，而拉米夫定和阿德福韦酯联合治疗组患者无1例出现(277)。

Dosage: The decrease of Adefovir dipivoxil tolerability at a dose of 30 mg in some patients, led to choosing the 10 mg dose as the best dose with regard to the benefit/risk ratio, and the 10 mg dose is the dose registered (223). The durability of the response after withdrawal of treatment is now becoming known. Of 60 patients undergoing HBe sero-conversion on adefovir, 91% were still HBe antigen negative after one year of follow-up (10). All the patients who relapsed were genotype C. However, cessation of therapy in some patients without HBe seroconversion or HBe negative patients was associated with relapse (129). Therefore, maintenance therapy is recommended. Preliminary results suggest that the antiviral effect is maintained and the rates of virological response with HBe seroconversion increases with the duration of therapy. However, a longer follow-up is planned (up to 5 years) in order to answer the question of the durability of the response under treatment and of the possible increased efficacy of long-term treatment.

剂量：一些接受30mg剂量阿德福韦酯的患者耐受性下降，考虑到效益/风险比，因而选择10mg作为最佳剂量，而且10mg也是为注册的剂量(223)。停止阿德福韦酯治疗后，应答持久性目前逐渐有所了解。60例患者阿德福韦治疗后发生HBe血清转换，91%的患者随访1年后，HBeAg仍然阴性(10)。所有复发患者均为基因型C。然而，一些无HBe血清转换或HBe阴性患者停止治疗伴有复发(129)。因此，推荐阿德福韦持续治疗。初步结果提示，阿德福韦存在持续抗病毒作用，HBe血清转换的病毒学应答率随治疗时间增加。但为了明确治疗应答的持久性，以及长期治疗可能增加的疗效，需要设计更长时间的随访研究（达5年）。

Adverse Effects: The tolerability and safety profile of adefovir at the dose of 10 mg was similar to that of the placebo. Adefovir at the dose of 30 mg was associated with increase in creatinine level in some patients. This increase was moderate, occured after 24 weeks of treatment, and resolved in all cases after withdrawal of the drug.

副作用：阿德福韦10mg治疗组的耐受性和安全性与安慰剂组相同。一些阿德福韦30mg治疗组患者伴有肌酐水平增加。肌酐水平的增加是轻度的，出现在治疗24周以后，停药后所有患者好转。

Resistance of HBV to adefovir: Genotypic resistance to adefovir dipivoxil in phase III trials shows a slower rate than lamivudine resistance, starting during the second year of therapy (129) to reach 29% after 5 years of administration in patients treated for HBeAg negative chronic hepatitis B (127) (Figure 4). Adefovir resistance mutants harbor a N236T and/or A181V/T amino acid substitution in the D and B domains of the viral polymerase respectively (7, 195, 346).

阿德福韦HBV耐药：Ⅲ期临床试验显示，阿德福韦酯基因型耐药率低于较拉米夫定，从治疗第2年开始发生(129)，治疗5年后，HBeAg阴性慢性乙肝患者变异率达29%(127) (图4)。阿德福韦耐药变异发生在在病毒多聚酶D区和B区，N236T和/或A181V/D氨基酸替代(7, 195, 346)。

Entecavir

恩替卡韦

Efficacy: Entecavir has been evaluated in several clinical trials including patients with HBeAg positive or HBeAg negative chronic hepatitis B patients, patients with lamivudine failure, HIV-HBV coinfected patients, and liver transplanted patients. More than 1600 patients were enrolled in phase III trials whose results led to the US FDA approval for the treatment of adult patients with chronic hepatitis B with evidence of viral replication and either evidence of persistent elevation of serum ALT levels or histologically active liver disease. In 1 randomized study involving nucleoside naive patients (HBeAg positive), entecavir administered 0.5 mg orally once daily for 52 weeks was superior to lamivudine (100 mg orally once daily for 52 weeks) on the primary efficacy endpoint of histological improvement (72% vs 62%) and on secondary endpoints, such as the reduction in viral load (-6.98 vs -5.46 log 10) and normalization of ALT (68% vs 60%) (45, 115) (Table 7). Results of entecavir administration for two years are also available in HBeAg positive patients with chronic hepatitis B. After 2 years of treatment, 81% of patients receiving entecavir had a viral load below 300 copies / mL versus only 39% of patients receiving lamivudine, 31% seronconverted to anti-HBe versus 26% in the lamivudine group, and 5% showed a clearance of HBsAg versus 3% in lamivudine treated patients (115). These results were also confirmed in HBe Ag-negative patients with chronic hepatitis (179). As in vitro studies had shown a partial cross-resistance of entecavir with lamivudine resistance mutations (199, 326), a randomized dose-ranging phase II study evaluating the efficacy of the switch to entecavir was performed in 182 lamivudine resistant patients (46). Entecavir administered at 1 mg once daily induced a significant viral load reduction and histological improvement, by comparison with the control group treated with lamivudine (46) (Table 7). Recently, another phase III, double-blind trial was performed on HBeAg positive patients who were refractory to lamivudine therapy (persistent viremia or documented YMDD mutations while receiving lamivudine). One hundred and forty one patients were switched to entecavir 1mg daily and 145 continue lamivudine 100mg daily for a minimum of 52 weeks. Histologic improvement occured in 55% of entecavir-treated vs 28% of lamivudine-treated patients. Mean change from baseline in HBV DNA was -5.11 log10 copies/mL for entecavir-treated patients and -0.48 log10 copies/mL for lamivudine-treated patients (306). Moreover, the results of several in vitro studies showed that entecavir inhibits the replication of adefovir resistant strains. These studies were performed with either cloned HBV genomes from clinical strains (346), or HBV genomes harboring a single point mutation introduced by site directed mutagenesis (28), and showed that the N236T polymerase mutant is as sensitive to entecavir as wild-type HBV. In agreement with these in vitro findings, a clinical report of eight patients found to have adefovir resistant HBV polymerase gene mutations showed that in two patients who received entecavir as a rescue therapy a decline of viral load by 4.3 and 5.5 log 10 copies/mL was observed (105).

疗效：恩替卡韦已在一些临床试验中被评估，患者人群包括HBeAg阳性或HBeAg阴性的慢性乙肝患者，拉米夫定变异患者，HIV-HBV同时感染患者，以及肝移植患者。1600多例患者入组Ⅲ期临床试验，研究结果使恩替卡韦得到美国FDA批准，用于治疗证实存在病毒复制，以及持续血清ALT水平升高，或组织学活动性肝病的慢性乙肝成人患者。一项关于核苷类初治患者（HBeAg阳性）的随机研究中，恩替卡韦口服，0.5mg/d，治疗52周，在组织学改善（72%/62%）第一疗效终点，以及病毒载量下降（-6.98/-5.46 log 10），和ALT正常（68%/60%）等第二疗效终点上均优于拉米夫定（100mg/d，口服治疗52周）(45, 115) (Table 7)。恩替卡韦治疗HBeAg阳性慢性乙肝患者2年的结果已出。恩替卡韦治疗2年后，81%的患者病毒载量<300 copies / mL，31%的患者抗HBe血清转换，5%的患者发生HBsAg清除，而拉米夫定治疗患者仅39%的患者病毒载量<300 copies / mL，26%的患者抗HBe血清转换，3%的患者发生HBsAg清除(115)。这些结果也在HBeAg阴性的慢性乙肝患者中被证实(179)。体外研究显示，恩替卡韦与拉米夫定耐药变异存在部分交叉耐药(199, 326)，因而在182例拉米夫定耐药患者中进行一项Ⅱ期剂量范围随机研究，评估改为恩替卡韦治疗的临床疗效(46)。较拉米夫定治疗相比，恩替卡韦1mg/d治疗可使病毒载量明显下降，组织学改善(46) (表7)。近来，另一项Ⅲ期双盲试验已在拉米夫定耐药（持续病毒血症，或拉米夫定治疗时证实存在YMDD变异）HBeAg阳性患者中展开。141例患者改为恩替卡韦治疗1mg/d，145例患者持续拉米夫定治疗100mg/d，持续治疗最少52周。较28%的拉米夫定治疗组患者相比，55%的恩替卡韦治疗组患者发生组织学改善。两组平均HBV DNA水平较基线分别下降5.11 log10 copies/mL和0.48 log10 copies/mL(306)。此外，一些体外研究结果显示，恩替卡韦可抑制阿德福韦耐药株复制。这些研究通过从临床病毒株中克隆HBV基因组(346)，或包含定向诱变引起单个点突变HBV基因组进行(28)，且研究显示N236T聚合酶突变体对恩替卡韦的敏感性与野生型HBV相同。一则关于阿德福韦耐药的临床报道与体外研究结果一致，8例患者存在HBV聚合酶基因变异，结果发现，2例恩替卡韦补救治疗患者病毒载量分别下降4.3和5.5 log 10 copies/mL (105)。

Hsin-Yun Sun, M.D. Entecavir Should Not Be Used for HBV Patients Co-Infected with HIV. 2008

Dosage: The recommended dose of entecavir is 0.5 mg once daily for nucleoside-naive CHB patients and 1.0 mg once daily in patients with lamivudine resistance or persistent HBV viremia during lamivudine therapy. As with the other nucleoside analogues, the suppression of HBV DNA is not durable after discontinuation of entecavir.

剂量：恩替卡韦用于核苷类初治CHB患者推荐剂量为0.5mg/d，用于拉米夫定耐药或拉米夫定治疗期间持续HBV病毒血症患者推荐剂量为1.0mg/d。和其它核苷类似物一样，停止恩替卡韦治疗后HBV DNA不能持久抑制。

Resistance of HBV to entecavir: The phase II study performed on the 182 lamivudine resistant patients revealed that known entecavir resistance mutations were noted in 6 patients at baseline and emerged in two patients during entecavir therapy while only one patient experienced a virological rebound during the study period. In recent and larger phase III trial of entecavir for lamivudine failure, the emergence of entecavir resistance was observed in 10% patients after 2 years of therapy (64). The molecular characterization of entecavir resistance mutations showed that (1) lamivudine resistance mutations confer some level of cross-resistance to entecavir; (2) additional mutations are required for entecavir resistance; (3) the latter are not sufficient to confer entecavir resistance when the lamivudine resistance mutations are absent (326). Several patterns of mutations were shown to confer entecavir resistance on a genetic background of lamivudine resistance: (1) substitutions I169T and M250V, (2) substitutions T184G and S202I (326), or (3) S202G (347) (Figure 3). In lamivudine naïve patients, the rate of resistance to entecavir seems to be low after 2 years of treatment (63).

恩替卡韦HBV耐药：一项182例拉米夫定耐药患者的Ⅱ期研究显示，治疗基线时6例患者已存在恩替卡韦耐药突变，治疗期间又有2例患者出现耐药突变，然而仅1例患者在研究期间发生病毒学反跳。近来，在较大规模的恩替卡韦治疗拉米夫定失败患者的Ⅲ期试验中，治疗2年后10%的患者出现恩替卡韦耐药(64)。恩替卡韦耐药变异的分子鉴定显示：(1)拉米夫定耐药变异与恩替卡韦存在一定水平的交叉耐药(2)；恩替卡韦耐药还需要存在其它变异(3)；如果不存在拉米夫定耐药变异，后者并不足以导致恩替卡韦耐药(326)。一些变异模式显示在拉米夫定耐药的基因背景下，可导致恩替卡韦耐药(1)：I169T 和 M250V取代(2)，T184G和S202I取代(326)，或S202G取代(347) (图3)。拉米夫定初治患者，治疗2年后恩替卡韦耐药率看来很低(63)。

Telbivudine

替比夫定

Efficacy: The safety, antiviral activity, and pharmacokinetics of telbivudine have been assessed in 43 adults with hepatitis B e antigen-positive chronic hepatitis B (178). This placebo-controlled dose-escalation trial investigated 6 telbivudine daily dosing levels (25, 50, 100, 200, 400, and 800 mg/d); treatment was given for 4 weeks. Telbivudine was well tolerated at all dosing levels, with no dose-related or treatment-related clinical or laboratory adverse events. Antiviral activity was dose-dependent, with a maximum at telbivudine doses of 400 mg/d or more. In the 800 mg/d cohort, the mean HBV DNA reduction was 3.75 log10 copies/mL at week 4, comprising a 99.98% reduction in serum viral load. Subsequently, large phase III studies have shown the superority of telbivudine compared to lamivudine in the suppression of viral load (by 6.5 log10 versus 5.5 log10) and improvement of liver histology (177).

疗效：以43例HBeAg阳性慢性乙肝成年患者为研究对象，对替夫比定的安全性、抗病毒活性和药代动力学进行评估(178)。该安慰剂对照、剂量递增试验对6种替比夫定日摄入剂量等级（25，50，100，200，400，800mg/d）进行研究，治疗时间为4周。替比夫定在所有研究剂量等级耐受好，没有与剂量有关或治疗有关的临床或实验不良事件。替比夫定抗病毒活性具有剂量依赖性，最大剂量为400mg/d或以上。在800mg/d实验组，平均HBVDNA水平在第4周时下降3.75 log10 copies/mL，其中血清病毒载量减少99.98%。随后，大规模Ⅲ期研究显示，较拉米夫定相比，替夫比定在抑制病毒载量（6.5 log10/5.5 log10）和改善肝组织方面更有优势(177)。

Resistance of HBV to telbivudine: Telbivudine resistance was observed in approximately 5% of patients after one year of therapy and associated with a M204I mutation in the viral polymerase (177).

替夫比定HBV耐药：治疗1年后，观察到约5%的患者发生替夫比定耐药，与病毒聚合酶M204I变异有关(177)。

Emtricitabine

恩曲他滨

Efficacy: In a randomized, double blind study, 98 asian patients (77 HBeAg-positive and 21 HBeAg-negative) were randomized to receive 25, 100 or 200 mg of emtricitabine daily for 48 weeks (197). At 48 weeks, the median decreases in viral load were 2.6 log10, 3.1 log10 and 2.9 log10 copies/mL for the 3 doses respectively. The proportions of patients with undetectable HBV DNA (below 4700 copies/mL) were 38%, 42% and 61% for the 3 doses respectively. HBeAg loss was observed in a high proportion (40%) of the HBeAg positive patients (ranging from 32 to 50% depending on the dose). The results of this study suggest that the optimal dose of emtricitabine is 200 mg once daily. Patients were then treated with open-label 200mg emtricitabine for an additional year at the end of the randomized phase (116). After two years, 53% of the patients had serum HBV DNA below 4,700 copies/ml, 33% seroconverted to anti-HBe and 85% had normal ALT. However, the role of emtricitabine as a monotherapy may be limited by its structural similarity to lamivudine with the risk of development of drug resistance.

疗效：一项随机、双盲研究中，98例亚洲患者（HBeAg阳性77例，HBeAg阴性21例）随机接受恩曲他滨25 mg/d，100 mg/d或200mg/d治疗，治疗时间为48周(197)。治疗第48周时，三组患者病毒载量中位数分别下降2.6 log10, 3.1 log10 和2.9 log10 copies/ml，分别有38%、42%和61%的患者HBVDNA检测不到（< 4700 copies/mL）。HBeAg阳性患者（32%-50%，与剂量有关）HBeAg转阴率高（40%）。本研究结果提示，恩曲他滨最佳治疗剂量是200mg/d，每天一次。随机治疗后，患者再开放接受恩曲他滨200mg治疗1年(116)。2年后，53%患者血清HBVDNA< 4700 copies/ml，33%的患者发生抗HBe血清转换，85%的患者ALT恢复正常。然而，恩曲他滨因为其结构与拉米夫定相似，有发生耐药的风险，限制了其单药治疗。

Dosage: Emtricitabine was recently licensed for the treatment of HIV-disease at a dose of 200 mg daily, which seems the effective dose also for HBV (116).

剂量：近来恩曲他滨被批准用于治疗HIV疾病，剂量为200mg/d, 该剂量也是HBV治疗的有效剂量(116)。

Resistance of HBV to emtricitabine: Genotypic analysis performed at week 8 of the previously described phase II clinical trial showed that 12% of patients treated with 100 mg of emtricitabine and 6% of those treated with 200 mg developed drug-resistant HBV. However, although emtricitabine exhibits the same mutation-profile as lamivudine, after 48 weeks only 12.6% of the 165 patients enrolled in the emtricitabine arm of phase III clinical trial developed YMDD mutation, and 18% at year 2 (116).

恩曲他滨HBV耐药：前面提及的Ⅱ期临床试验治疗第8周时，基因型分析结果显示，恩曲他滨100mg治疗组12%的患者、恩曲他滨200mg治疗组6%的患者出现药物HBV耐药。然而，尽管恩曲他滨与拉米夫定耐药突变谱相同，但在恩曲他滨Ⅲ期临床试验中，入组研究的165例患者治疗48周后，仅12.6%的患者发生YMDD变异，治疗第2年为18%(116)。

Tenofovir

替诺福韦

Efficacy: In a pilot, nonrandomized study on 53 lamivudine-resistant HBV infected patients, tenofovir showed an earlier and stronger efficacy in suppressing HBV DNA than adefovir: at week 48, only 44% of the 35 adefovir patients had HBV DNA levels below 105 copies/mL in contrast to 100% of the 18 tenofovir-treated patients (337). The anti-HBV efficacy of tenofovir was confirmed in several other studies performed in HIV/HBV coinfected patients (22, 172).

疗效：一项关于53例拉米夫定耐药HBV患者的非随机、初步研究，结果显示，替诺福韦比阿德福韦在抑制HBV DNA方面疗效更早、更强：治疗第48周时，35例阿德福韦治疗患者中仅44%的患者HBV DNA 低于10⁵copies/mL，而18例替诺福韦治疗患者HBV DNA全部低于10⁵copies/mL (337)。其它一些研究进一步证实，替诺福韦在HBV/HIV共感染患者中的抗HBV疗效(22, 172)。

Dosage: Tenofovir is a nucleotide analogue which inhibits both HIV and HBV replication at a dose of 300 mg given once daily. It is licensed for the treatment of HIV infection. Phase III clinical trials are ongoing in HBV infected patients to fully evaluate its efficacy.

剂量：替诺福韦是一种核苷酸类似物，抑制HIV和HBV复制的治疗剂量为300mg，每日一次。它已被批准用于HIV感染的治疗。正在进行HBV感染患者Ⅲ期临床实验，以全面的评估其疗效。

Resistance of HBV to tenofovir: No evidence of phenotypic viral resistance could be demonstrated in the tenofovir-treated patients in the long-term follow-up (up to 130 weeks), although a controversy has emerged for one mutation (80, 304).

替诺福韦HBV耐药：尽管对一个变异存在争议，但在对替诺福韦治疗患者的长期随访中（130周）并没有发现病毒表型耐药存在的证据(80, 304)。

FDA Approves Tenofovir for Hepatitis B. 2008.

Marcellin P, et al. Tenofovir disoproxil fumarate versus aadefovir dipivoxil for chronic hepatitis B. NEJM 2008;359:2442-2455.

Combinations of Antiviral Agents (Table 8)

联合药物抗病毒治疗(表 8)

Monotherapy is not sufficient to eradicate HBV in the majority of patients who are chronically infected, as observed during clinical trials or in clinical practice. Combined chemotherapy, including concurrent or sequential treatment using more than one drug, provides in theory several advantages over monotherapy; this has been recently demonstrated in practice for HIV chemotherapy and for HBV (214, 303). Several types of combination have been or are being tested in clinical trials for the treatment of chronic hepatitis B.

　　临床实验或实践中观察到，单药治疗不足以清除大多数慢性乙肝患者体内HBV。同时联合或序贯使用一种以上药物联合治疗，理论上说优于单药治疗。近来关于HIV和HBV的治疗实践已经显示了这一点(214, 303)。几种不同类型的联合治疗方案治疗慢性乙肝的临床治疗试验已经或正在进行中。

Combination of IFN with lamivudine

干扰素联合拉米夫定

For historic reasons, the first combination to be tested was between IFN and lamivudine. Previous studies on the combination of IFN and lamivudine suggested that this combination could be more effective than lamivudine monotherapy (290). However, the results of different studies were discordant which could be due to different treatment regimens which could not be optimal.

　　由于历史原因，IFN与拉米夫定是第一葛接受验证的药物组合。既往研究发现，IFN与拉米夫定联合治疗，疗效优于拉米夫定单药治疗 (290)。然而，不同的研究治疗结果并不一致，这可能与药物方案不同或非最佳选择有关。

In a large randomized controlled study, 307 patients with HBeAg-positive chronic hepatitis B were randomized to receive either the combination of PEG IFN alpha 2b 100 µg per week for 52 weeks then 50 µg for 20 weeks and lamivudine 100 mg per day or PEG IFN alpha 2b at the same dose with placebo (155). At the end of the 26-week post treatment follow-up, there was no difference in response rates between the two treatment groups: serum HBV DNA was undetectable by PCR (below 400 copies per mL) in 7% and 9%; HBeAg seroconversion was both observed in 29%; normal ALT was obtained in 32% and 35%) in the PEG IFN monotherapy and the PEG IFN with lamivudine combination therapy groups. This study shows that in patients with HBeAg-positive chronic hepatitis B, 26 weeks after therapy, the combination of PEG IFN alpha 2b with lamivudine (with the simultaneous regimen used) is not superior to PEG IFN alpha 2b used in monotherapy. Main predictors of response were HBV genotype and pretreatment ALT level. Response was 34% for those with ALT levels under 3 times the upper limit of normal (3xULN) and 50% of those with ALT levels above 5xULN. Response was 60% for genotype A versus 42% for genotype B, 32% for genotype C and 28% for genotype D.

　　一项大型随机对照研究中，307例HBeAg阳性的慢性乙肝患者接受随机治疗：一组为联合治疗，使用PEG IFN α-2b，100µg/周，治疗52周，然后50µg/周，治疗20周，同时应用拉米夫定100mg/d；另一组为单药治疗，使用相同剂量PEG IFNα-2b联合安慰剂治疗(155)。治疗结束后第26周，两治疗组应答率无差异：PCR法（低于400 copies/mL）检测不到血清HBV DNA的比例分别为7%和9%， HBeAg发生血清转换比例均为29%，ALT达到正常比例分别为32%和35%。该研究显示，HBeAg阳性慢性乙肝患者治疗26周后， PEG IFN α-2b与拉米夫定联合治疗（治疗同时进行）的疗效并不优于PEG IFN α-2b单药治疗。应答主要预测因素为HBV基因型和治疗前ALT水平。ALT 水平高于正常上限3倍的患者（3xULN），应答率是34%，高于上限5倍患者，应答率为50%。基因型A型的应答率为60%，B型为42%，C型为32%，D型为28%。

Lau et al. (2005) recently reported the results of a phase III study evaluating pegylated IFN alpha 2a in 814 patients with HBeAg-positive chronic hepatitis B(187). They compared three treatment groups: pegylated IFN alpha 2a 180 mg once weekly plus placebo, pegylated IFN alpha 2a 180 mg plus lamivudine 100 mg daily, and lamivudine alone. The duration of therapy was 48 weeks, with a 24-week follow-up. After 24 weeks of follow-up, significantly more patients who received peginterferon alpha 2a monotherapy or peginterferon alpha 2a plus lamivudine than those who received lamivudine monotherapy had HBeAg seroconversion (32% vs. 19% (P<0.001) and 27% vs. 19% (P=0.02), respectively) or HBV DNA levels below 100 000 copies per mL (32% vs. 22% (P=0.01) and 34% vs. 22% (P=0.003), respectively). However, there was no benefit of combination therapy in comparison with peginterferon alpha 2a monotherapy. The same was true in the study of HBe Ag-negative patients (224)

　　最近Lau等（2005）报道了Ⅲ期临床实验评估PEG IFN α-2b治疗814例HBeAg阳性慢性乙肝患者的结果(187)。研究分为三个治疗组进行比较：PEG IFN α-2a 180mg，1次/周+安慰剂；PEG IFN α-2a 180mg+拉米夫定100mg/d；拉米夫定单药治疗。治疗时间为48周，随访时间为24周。随访24 周后，较拉米夫定单药治疗患者相比，PEG IFN α-2s单药治疗，或PEG IFN α-2a+拉米夫定治疗患者HBeAg血清转换率明显更高（分别为32%/19%，P<0.001；27% /19%，P=0.02），HBV DNA 载量低于100 000 copies/mL 患者比例更高(32%/22%，P=0.01；34%/22%，P=0.003)。然而，PEG IFN α-2a与拉米夫定联合治疗与PEG IFN α-2a单药治疗相比无差异。该结果也适用于HBe Ag阴性患者(224)。

Combination of Adefovir with Lamivudine in Lamivudine-Resistant Patients

阿德福韦与拉米夫定联合治疗拉米夫定耐药患者

The concept of improving the efficacy by combining two analogues is based on the hypothesis that the combination would maximise the viral suppression and would decrease the occurence of viral resistance.

　　联合两种核苷类似物治疗能提高疗效的概念是基于联合治疗能最大程度抑制病毒复制，降低病毒耐药的发生率。

One randomized study evaluated the efficacy of the combination of adefovir with lamivudine as compared to lamivudine alone or adefovir alone in 59 patients with HBeAg-positive chronic hepatitis B with lamivudine resistant HBV (273). In contrast to lamivudine monotherapy group, there was no significant difference in median serum HBV DNA reduction (-3.59 and -4.04log copies/mL), rates of ALT normalization (53% and 47%) and HBeAg loss (3 patients in each group) between the adefovir-lamivudine combination group and the adefovir monotherapy group. Noteworthy, serum HBV DNA level remained stable and there was no significant biochemical or serological change during the monotherapy.

　　一项随机研究比较了阿德福韦和拉米夫定联合治疗与阿德福韦或拉米夫定单药治疗的疗效，研究对象是59例HBeAg阳性拉米夫定耐药的慢性乙肝患者(273)。与拉米夫定单药治疗患者组相比，阿德福韦+拉米夫定联合治疗组与阿德福韦单药治疗组在血清HBV DNA中位数减少（-3.59和-4.04log copies/mL）、ALT复常率（53%和47%）和HBeAg转阴（每组3例患者）等方面无显著性差异。值得注意的是，在单药治疗期间，患者血清HBV DNA水平保持稳定，无显著生化学或血清学改变。

Another study compared the efficacy of the combination of adefovir with lamivudine versus lamivudine used in monotherapy in 95 lamivudine-resistant (270). There was a significant difference in median serum HBV DNA reduction (-4.6 vs +0.30 log copies/mL), rates of undetectable HBV DNA with PCR (33% vs 4%) and HBeAg seroconversion (8% vs 2%) between the adefovir-lamivudine combination group and the lamivudine monotherapy group.

　　另一项研究对阿德福韦和拉米夫定联合治疗与拉米夫定单药治疗的疗效进行了比较，研究对象是95例拉米夫定耐药患者(270)。研究发现，两组患者在血清HBVDNA中位数减少(-4.6/+0.30 log copies/mL)、PCR法HBVDNA未检出率（33%/4%）和HBeAg血清转换率(8% /2%)上存在显著差异。

A recent study showed the benefit of the long-term treatment with the combination of adefovir and lamivudine as compared to adefovir monotherapy in HBe-negative lamivudine resistant patients (277). Others studies also showed the benefit of early adefovir add-on with continuing lamivudine in patients with lamivudine resistance. These studies showed a benefit interest of limiting the risk of adefovir resistance and of controlling liver disease with the adefovir add-on strategy (106, 182, 277).

　　最近一项研究显示，长期使用阿德福韦与拉米夫定联合治疗HBeAg阴性拉米夫定耐药患者，疗效优于阿德福韦单药治疗(277)。其他研究也发现，拉米夫定耐药患者在继续使用拉米夫定的基础上及早加用阿德福韦治疗有益。这些研究结果都表明，加用阿德福韦的治疗策略有利于降低发生阿德福韦耐药的风险、控制肝病(106, 182, 277)。

De Novo Combination Therapy

重新认识联合治疗

The optimal antiviral regimen may combine drugs with a different mechanism of action on viral replication, lacking cross-resistance and exhibiting antiviral synergy. This theoretical type of combinations should reduce the risk of selection of drug resistant mutants because of the inhibition of viral replication and the selective pressure exerted on the different viral strains that compose the quasi-species. Up to now, combination of nucleoside analogues has not shown a synergistic antiviral effect in clinical trials, mainly because these antiviral agents inhibit a single target, i.e. the viral polymerase (see above). With the development and evaluation of newer drugs acting at different steps of the viral genome replication, combination relying on drugs with different mechanism of action can be evaluated using for instance drugs with potent anti-priming activity, drugs inhibiting viral minus strand DNA and others inhibiting plus strand DNA synthesis. The combination of such compounds was found to be either additive and more rarely synergistic in polymerase assays (reverse transcriptase activity) (300) as well as in tissue culture experiments (viral DNA synthesis) or in chronically infected woodchucks (166, 167). Although some of the combinations based on the inhibition of all three steps of viral genome replication inhibited more potently viral DNA synthesis than the single drugs, none were able to completely prevent the initial formation of viral ccc-DNA following de novo infection of hepatocytes, or to clear ccc-DNA once chronic infection of hepatocytes has been established in tissue culture (300). However, such combinations by inhibiting more potently viral DNA synthesis may delay the onset of viral resistance by limiting the chance of a given mutation to occur.

　　最佳抗病毒治疗方案是使用作用于病毒复制不同机制、无交叉耐药性及存在抗病毒协同作用的药物联合治疗。这种理论上的联合类型，因为抑制毒病复制以及对不同准种组成的病毒株均施加选择压力，可以减少药物选择耐药变异的风险。到目前为止，在临床试验中，核苷类药物联合治疗还没有显示其抗病毒的协同作用，主要原因在于这些抗病毒药物作用的是单一靶点，如病毒聚合酶（见上述）。随着作用于病毒基因组复制不同步骤新药的发展和评估，如有效抗引物活性药物，抑制病毒负链DNA药物和其它抑制病毒正链DNA合成药物等不同作用机制药物的联合治疗被评估。在聚合酶测定中（逆转录酶活性） (300)发现，不管是组织培养（病毒DNA合成），还是土拨鼠的慢性感染(166, 167)，这些药物联合表现出相加作用，很少有协同作用。虽然作用于病毒基因组复制所有3个步骤的一些药物联合治疗，比单药治疗能更有效抑制病毒基因合成，但是都不能完全阻止肝细胞初发感染后病毒ccc-DNA的初步形成，或在细胞培养中(300)，肝细胞慢性感染建立后清除ccc-DNA。然而，这种能更有效抑制病毒DNA合成的联合药物治疗，通过减少已知变异发生的机会，可使病毒产生耐药的时间延迟。

A multitude of other combinations involving different immunomodulators and/or reverse transcriptase inhibitors has been tried in clinical setting (303). But so far, their benefit is not clearly established. The ideal combination will likely involve 2 or 3 drugs that have different mechanism of action (e. g. one or 2 inhibitor(s) of reverse transcriptase plus immunomodulator, or inhibitor(s) of RT plus inhibitor of morphogenesis). As new anti-HBV agents become available, the search for optimal combination of drugs without cross-resistance will continue (for review see Zoulim F. (381)).

　　许多其它联合治疗，包括不同的免疫调节剂和/或逆转录酶抑制剂已经被试用于临床治疗中(303)。但到目前为止，其益处还不明确。理想的联合治疗可能涉及2种或3种不同作用机制的药物（如1种或2种逆转录酶抑制剂联合免疫调节剂，或者逆转录酶抑制剂联合病毒形成抑制剂）。随着新的抗HBV药物的出现，对无交叉耐药的最佳联合治疗的研究将不断进行（叙述见Zoulim F. (381)）。

(Printable Version of Alternative Therapy for Hepatitis B Virus)

Special Infections

特殊类型的感染

Patients With Hepatitis B e Antigen ( HBeAg)-Negative Chronic Hepatitis B: This form of chronic hepatitis B is mostly associated to the presence of replication-competent pre-core mutants that, contrary to the wild-type HBV, are unable to produce HBeAg (37). These mutants are selected either spontaneously following natural anti-HBe seroconversion in one fourth to one third of patients (132) or during antiviral therapy. The natural history of HBeAg-negative chronic hepatitis B is characterized by a spontaneous fluctuation of ALT levels and HBV DNA load. Moreover, HBeAg-negative chronic hepatitis B usually has an aggressive course with rapid progression to cirrhosis and frequent development of hepatocellular carcinoma (262). Pre-core mutant chronic hepatitis B exists worldwide, but is particularly common in Mediterranean Europe and Asia where its represents a concern and a real therapeutic challenge.

HBeAg阴性慢性乙型肝炎患者：这种类型的慢性乙型肝炎大部分与有复制能力的前C区突变有关，与野生型HBV不同，这种变异体不能产生HBeAg(37)。1/4~3/4的患者在抗HBe自然血清转换后自发突变(132)，或者在抗病毒治疗期间出现选择变异。HBeAg阴性慢性乙型肝炎的自然史主要表现为ALT水平和HBV DNA载量的自发波动。此外，HBeAg阴性慢性乙型肝炎通常病程进展更快，很快进展到肝硬化和随后发生肝细胞癌(262)。前C区变异的慢性乙型肝炎存在于世界各地，但特别常见于欧洲地中海及亚洲区域，这引起了更多的关注，是治疗方面的真正挑战。

Interferon-alpha has been the treatment of choice for chronic hepatitis B during the last decade (145). Unfortunately, its efficacy in patients with HBeAg-negative chronic hepatitis is limited. Although, 40 to 90% of patients treated with IFN-alpha achieve remission at the end of 6 to 24 months therapy, the majority of them relapse soon after cessation of treatment (29, 180), a sustained virological and biochemical response being obtained in 20-25% of the cases and only with long treatment/re-treatment (222).

　　过去的十年间，IFN-α一直用于治疗慢性乙型肝炎(145)。遗憾的是IFN-α治疗HBeAg阴性慢性肝炎的疗效有限。尽管IFN-α治疗6-24个月后， 40%-90%的患者病情有所缓解，但大部分患者停止治疗后不久，病情复发(29, 180)，仅在长期/反复接受治疗的患者中，20%-25%的患者会出现持续病毒学和生化学应答(222)。

Lamivudine administration has been evaluated in patients with HBeAg negative chronic hepatitis B in randomized trials and in cohort studies. Given at a dose of 100-150 mg daily for 52 weeks, lamivudine induces a marked suppression of serum HBV-DNA accompanied by normalization of ALT in approximately 80 % of the patients, and by liver histology improvement. However, with a few exceptions, treated patients do not clear HBsAg and are subject to disease reactivation after discontinuing therapy (325). Long-term therapy is therefore recommended. Unfortunately, prolonged lamivudine administration is hampered by the emergence of drug resistance. Long-term lamivudine studies have shown that after reaching a peak between 6 and 12 months of therapy, the response rate decreases because of virological breakthroughs associated with the emergence of lamivudine-resistant HBV mutants. In a study, the virological response diminished from 68% at month 12 and 24 to 52% and 41.6%, respectively at month 18 and 24 of therapy (128). Long term studies showed that the antiviral efficacy and histological improvement is progressively lost with time, as the prevalence of resistance mutations is increasing (281). After 3 to 4 years of therapy, the percentage of lamivudine resistance offsets the percentage of patients initially responding (33, 85, 261, 281). ALT levels increase progressively with the duration of infection with the YMDD mutants : no patient who developed lamivudine resistance mutation for 24 months had normal ALT levels (261, 280). In a retrospective nationwide analysis of lamivudine therapy in Italy, the development of clinically important events after virologic breakthroughs depended on the severity of the underlying liver disease; severe hepatitis flares at the emergence of YMDD were noted in patients with child B and C cirrhosis but not in patients with non-cirrhotic chronic hepatitis (85), in agreement with previous studies (128, 247). The rate of resistance observed in patients with HBeAg-negative chronic hepatitis was similar to that observed in HBe-positive chronic hepatitis (186, 261). As in HBeAg-positive patients, treatment by adefovir is generally effective in patients who develop lamivudine resistance.

　　拉米夫定治疗HBeAg阴性慢性乙肝患者的疗效已在随机对照实验和队列研究中被评估。拉米夫定100-150mg/d，治疗52周，大约80%的患者血清HBV-DNA载量明显下降，伴有ALT水平恢复正常，以及肝脏组织学改善。然而，除了极个别患者外，治疗患者HBsAg 不能清除，停止治疗后疾病复发(325)。因而推荐患者长期治疗。不幸的是，由于药物耐药的出现，阻碍了拉米夫定的持续治疗。长期研究显示，使用拉米夫定治疗6-12个月期间，应答率达到峰值后，由于拉米夫定HBV耐药变异出现，发生病毒学反跳，应答率降低。一项研究发现，在12-24个月治疗中，病毒学应答率在治疗第18个月时，从68%降低至52%，治疗第24个月时降低至41.6% (128)。长期研究表明，由于耐药变异率增加，抗病毒疗效和组织学改善随时间的延长而减少(281)。经过3~4年治疗后，患者由最初的应答转为对拉米夫定产生耐药。伴随着YMDD变异的出现，ALT水平进行性升高，发生耐药变异24个月后患者ALT水平均不正常(261, 280)。一项意大利对拉米定夫治疗的全国回顾性调查分析，认为病毒学突破后重要临床事件的发生取决于基础肝脏疾病的严重程度；在child B级、C级肝硬化患者中观察到YMDD出现时存在严重肝炎活动，而在无肝硬化的慢性肝炎患者中未发现此现象(85)，这与以前的研究结果一致(128, 247)。研究发现，HBeAg阴性慢性肝炎与HBeAg阳性慢性肝炎患者，耐药的发生率相同(186, 261)。HBeAg阳性患者发生拉米夫定耐药后，使用阿德福韦治疗普遍有效。

Adefovir dipivoxil administration given for 48 weeks in HBeAg negative patients (131) induced in 64% of patients an improvement of histologic liver abnormalities, compared with 33% of patients who received placebo (P<0.001) (Table 6). Serum HBV DNA levels were reduced to < 400 copies/mL in 51% of patients in the adefovir dipivoxil group (63 of 123) and in 0% in the placebo group (P<0.001). The median decrease in log-transformed HBV DNA levels was greater with adefovir dipivoxil treatment than with placebo (3.91 vs. 1.35 log copies/mL , P<0.001). ALT levels had normalized at week 48 in 72% of patients receiving adefovir dipivoxil (84 of 116), compared with 29% of those receiving placebo (17 of 59, P<0.001) (131). A longer duration study for 144 weeks showed a median decrease in serum HBV DNA of 3.47 log10 copies/ml at 96 weeks and 3.63 log10 copies/ml at week 144 (129). HBV DNA was below 1000 copies/ml in 71% and 79% patients after 96 and 144 weeks respectively. Interestingly, in the majority of patients who were switched from adefovir to placebo, the benefit of treatment was lost, indicating that antiviral therapy with nucleoside analogues has to be prolonged in this patient population to avoid viral reactivation and ALT flares. Resistance mutations rtN236T and rtA181V were identified in 3% and 5.9% of patients after 96 and 144 weeks respectively. Side effects after 144 weeks were similar to those observed at week 48. Recent studies showed the clinical response after 5 years of therapy : 70% of patients had a suppression of viral load below the limit of detection of PCR assay, which was accompanied by ALT normalization and histology improvement. Development of adefovir resistant mutations was observed in 29% of patients (127).

　　HBeAg 阴性患者阿德福韦酯治疗48周，64%的患者肝脏组织学异常情况出现改善。而33%的安慰剂治疗患者出现好转（P<0.001）(表6)。阿德福韦酯治疗组51%(63 /123)的患者血清HBV DNA水平降至< 400 copies/mL，而在安慰剂治疗组患者为0%（P<0.001）。对HBV DNA水平进行 log转换后，阿德福韦酯治疗组患者中位数下降较安慰剂治疗组更明显(3.91/1.35 log copies/mL , P<0.001)。治疗第48周，阿德福韦酯治疗组72%的患者ALT水平恢复正常(84/116)，而安慰剂治疗组患者为29%（17/59, P<0.001）(131)。一项持续长达144周的研究显示，治疗第96周，血清HBV DNA中位数下降3.47 log10 copies/ml，第144周时下降3.63 log10 copies/ml(129)。治疗96周和144周后，分别有71% 和79%的患者HBV DNA< 1000 copies/ml。有意义的是，大部分患者从接受阿德福韦酯治疗转为安慰剂治疗后，疗效消失，这提示核苷类似物抗病毒治疗必须长期持续下去，以避免病毒再次复制和ALT波动。治疗第96周和第144周时，分别有3%和5.9%的患者出现rtN236T 和 rtA181V位点耐药变异。治疗144周后观察到的副作用与治疗第48周时相同。近来的研究显示了治疗5年的临床应答情况：70%的患者病毒载量得到抑制，且低于PCR检测的下限，并伴有ALT正常和组织学改善。据观察，29%的患者发生阿德福韦酯耐药变异。

Entecavir administration in 1 randomized study involving nucleoside naive patients (HBeAg negative), was superior to lamivudine (100 mg orally once daily for 52 weeks) on the primary efficacy endpoint of histological improvement (70% vs 61%) and on secondary endpoints, such as the reduction in viral load (-5 vs -4.5 log 10) and normalization of ALT (78% vs 71%) (179).

　　在一项关于核苷类初治患者（HBeAg阴性）的随机研究中，在主要疗效终点组织学改善 (70%/61%)，以及次要疗效终点，如病毒载量减少（-5 / -4.5 log 10）和ALT正常化（78% /71%）方面,恩替卡韦疗效优于拉米夫定（100 mg口服，每天一次，治疗52周），。

Combination of pegIFN alpha 2a with lamivudine : A study evaluated the efficacy of a combination of pegIFN alpha 2a with lamivudine, in comparison with pegIFN alone and lamivudine alone (224). Treatment was administered for 48 weeks and end points were analyzed 24 weeks post-treatment. During therapy, there was a benefit in the combination by comparison with the single treatment in terms of viral load decline. The rate of lamivudine resistance was lower in patients who received the combination of lamivudine with pegIFN by comparison with lamivudine monotherapy. However, 24 weeks post-therapy, there was no difference in the rate of ALT normalization (approximately 60%) or virologic response (approximately 20% patients) between the groups who received pegIFN alone or in combination with lamivudine. The two groups of patients who received pegIFN had a better response rate 24 weeks post-therapy compared to the group who received lamivudine alone. In view of the fluctuating nature of HBeAg-negative disease, long-term follow-up studies are necessary to determine whether the response is indeed sustained.

　　pegIFN α-2a联合拉米夫定治疗：一项研究对pegIFN α-2a单药治疗、拉米夫定单药治疗及pegIFN α-2a和拉米夫定联合治疗的疗效进行评估(224)。治疗时间为48周，治疗结束后24周分析终点。在治疗期间，联合治疗在降低病毒载量方面比单药治疗效果明显。较拉米夫定单药治疗相比，pegIFN和拉米夫定联合治疗患者拉米夫定的耐药发生率较低。然而，治疗后第24周，ALT复常率（大约60%）及病毒学应答率（大约20%患者）在pegIFN单药治疗或联合拉米夫定治疗组间无差异。治疗后24周，pegIFN治疗的两组患者比单用拉米夫定治疗的患者应答率更高。由于HBeAg阴性患者病情本身具有波动性，需要长期的随访以明确应答是否确实持续。

Decompensated Cirrhosis: The prognosis of decompensated liver cirrhosis resulting from chronic hepatitis B is poor. Antiviral intervention has been evaluated in terms of risk-benefit with interferon-alpha and nucleoside analogues. Standard IFN-alpha regimens can be dangerous in this group of patients. It is thought that the immune lysis of infected hepatocytes, which follows successful IFN-alpha therapy, can cause a reduction in the functioning cell mass of the patient with end-stage disease, and result in fatal exacerbation of disease activity. Therefore, treatment with IFN-alpha , if chosen, must be performed only with a careful clinical monitoring. The starting dose of 0.5 million units 3 times weekly should be increases slowly according to patient's tolerance.

失代偿肝硬化：慢性乙型肝炎引起的失代偿肝硬化预后很差。IFN-α和核苷类似物进行抗病毒治疗的风险-效益已被评估。普通IFN-α治疗对这类患者可能有危险。认为在成功IFN-α治疗同时，伴有感染肝细胞的免疫溶解，这能造成晚期肝病患者大量功能细胞群减少，导致致命的病情恶化。因此，如果选择IFN-α治疗，必须在密切临床监测下进行。起始剂量为0.5 MU，每周3次，可以根据患者的耐受性缓慢增加剂量。

The efficacy of lamivudine has been evaluated in several studies patients with decompensated cirrhosis. In the first study (345), 7 patients out of 33 underwent liver transplantation within 6 months after treatment initiation, 5 patients died, and 23 patients were treated for more than 6 months. In these latter patients, serum bilirubin decreased significantly, albumin levels increased and Child-Pugh score decreased significantly. Liver function improvement was slow but concomitant with the control of viral replication. Other studies including 13 and 18 patients respectively (158, 367), confirmed that lamivudine therapy appears highly effective in controlling viral replication and in improving liver functions in this serious clinical situation. In the last study, thirty patients with HBV-related decompensated and active viral replication were treated with lamivudine 100 mg daily for a median duration of 9 months. Among these patients, five patients died within 3 months. Two patients were lost to follow-up at week 8 and 9. One patient was treated for <6 months. Twenty-two patients were treated over 6 months. Univariate analysis revealed that the total bilirubin (P = 0.008), prothrombin time (P = 0.004), Child-Turcotte-Pugh score (P = 0.005), the model of efd-stage liver disease score (P = 0.004) and stage III hepatic encephalopathy (P = 0.001) were predictive factors of early mortality. Multivariate analysis revealed that the independent factor associated with early mortality was stage III encephalopathy. Among 22 patients, liver function improved markedly after lamivudine therapy. Of the nine hepatitis B e antigen (HBeAg)-positive patients, three had HBeAg seroconversion. Two patients had YMDD mutant and virological breakthrough at 41 and 46 weeks. One of the two had hepatocellular carcinoma and died of hepatic failure at week 125; the other received adefovir and is doing well. Lamivudine appeared to have benefits in viral suppression and significant improvement in liver function in patients with HBV-related decompensated. As noted in prior studies, poor baseline liver function is associated with a poor prognosis in patients with decompensated HBV cirrhosis treated with lamivudine (334).

　　拉米夫定疗效已在对一些失代偿肝硬化患者的研究中进行评估。在首次研究中(345)，33例患者开始拉米夫定治疗，其中7例患者在治疗后6个月内进行肝移植，5例患者死亡，23例患者治疗超过6个月。后面的这些患者血清胆红素显著减少，白蛋白水平增加，Child-Pugh评分显著下降。患者肝功能改善较慢，但病毒复制得到控制。其它研究分别有13例和18例患者入组研究(158, 367)，证明拉米夫定在病情严重时，能极有效的控制病毒复制和改善肝功能。最后一项研究中，30例HBV相关失代偿合并病毒复制活跃的患者，予以拉米夫定治疗，100mg/d，平均治疗时间为9个月。其中5例患者在3个月内死亡。2例患者在治疗第8周和第9周时失访。1例患者治疗时间< 6个月。22例患者治疗时间> 6个月。单变量分析显示，总胆红素（P = 0.008）, 凝血酶原时间（P = 0.004）, Child-Turcotte-Pugh评分（P = 0.005）, 终末期肝病模型评分（P = 0.004）和肝性脑病III 期（P = 0.001）是早期死亡的预测因子。多变量分析显示，III期肝性脑病是早期死亡相关的独立因素。22例患者接受拉米夫定治疗后，肝功能显著改善。在9例HBeAg阳性患者中，3例患者发生HbeAg血清转换。2例患者在治疗第41周和第46周发生YMDD变异和病毒学突破。其中1例患者出现肝细胞癌，在治疗第125周死于肝衰竭；另1例患者予以阿德福韦治疗，病情恢复。拉米夫定用于治疗HBV相关失代偿患者，其益处表现为病毒抑制和肝功能显著改善。如前面研究所提到的，接受拉米夫定治疗的失代偿HBV肝硬化患者，肝功能基线情况越差，预后越差(334)。

So, lamivudine therapy is associated with rapid viral suppression, improvement in Child-Pugh scores, and improved survival, but drug resistance is a major problem and is associated directly with a poor clinical outcome. Adefovir or entecavir is preferred in patients with decompensated cirrhosis who require long duration of treatment, due to the lower rate of development of resistance.

　　因此，拉米夫定治疗可以迅速抑制病毒，改善Child-Pugh评分和提高生存率，但药物耐药是一个主要问题，并且直接与不良临床结局有关。需要长期治疗的失代偿肝硬化患者，首选阿德福韦或恩替卡韦治疗，因为它们发生耐药的几率较低。

The safety and efficacy of switching to adefovir monotherapy was examined in compensated and decompensated patients with liver cirrhosis. The clinical, biochemical and virological responses were compared between adefovir monotherapy in 18 cirrhotic patients and adefovir add-on lamivudine therapy in 10 comparable cirrhotic patients with lamivudine-resistant rtM204 I/V (206). After switching to adefovir monotherapy, Child-Pugh's score, serum alanine aminotransferase (ALT), bilirubin, albumin and HBV DNA levels improved significantly (P < 0.01). Serum HBV DNA response, defined as HBV DNA decreased to below 105 copies/mL or > or =2 log10 reduction form baseline, was achieved in all patients. A transient ALT flare without concurrent changes in serum bilirubin or prothrombin time was observed in only two patients (11%). In this study, the efficacy and safety profile was similar to those with adefovir add-on lamivudine therapy, but recent studies showed that adefovir add-on lamivudine therapy was more beneficial to chronically infected patients with lamivudine-resistant mutants than adefovir switch (181).

　　在代偿和失代偿的肝硬化患者中，对改用阿德福韦单药治疗的安全性和疗效进行验证。18例拉米夫定rtM204 I/V耐药的肝硬化患者接受阿德福韦单药治疗，10例肝硬化耐药患者接受阿德福韦和拉米夫定联合治疗(206)，对两组间临床应答、生化学应答和病毒学应答进行比较。患者转为阿德福韦单药治疗后， Child-Pugh评分，血清丙氨酸转氨酶（ALT）、胆红素、白蛋白和HBV DNA水平显著改善（P < 0.01）。所有患者都获得血清HBV DNA应答，即较基线水平HBV DNA降至< 10⁵copies/mL或下降≥2 log10。仅2例患者（11%）出现一过性ALT波动，不伴有血清胆红素或凝血酶原时间变化。该研究显示，阿德福韦单药治疗的疗效和安全性与阿德福韦联合拉米夫定治疗相同，但近来的研究表明，对于拉米夫定耐药变异的慢性感染患者，阿德福韦联合拉米夫定治疗比转为阿德福韦单药治疗更好。

Underlying Diseases

基础疾病

Co-infection HBV and HIV: About 10% of people, who are infected with HIV-1, are co-infected with HBV. These patients have higher risk of HBV-related cirrhosis than HIV-negative HBV-infected patients, and co-infection have been associated to decrease survival in affected individuals (61).

HBV和HIV合并感染： HIV-1感染人群中，大约10%同时感染HBV。较HIV阴性 HBV感染患者相比，这些患者发生HBV相关肝硬化的风险更高。在感染人群中，合并感染与生存率降低有关(61)。

Lamivudine, administered at 100 mg/day or 300 mg/day (co-infection), inhibits HBV replication in more than 80% of infected patients with or without HIV-1 co-infection (21, 23, 291). However, the same problem of selection of drug resistant mutants during prolonged therapy is encountered for co-infected patients. Lamivudine-resistant HBV is found in about 15-32% of co-infected patients after 1 year of lamivudine therapy. It is anticipated that these patients who are receiving highly active antiretroviral therapy (HAART) might be more susceptible to progressive liver disease.

　　拉米夫定治疗100 mg/d，或者300mg/d（合并感染）时，超过80%的患者（有或无HIV-1合并感染）HBV病毒复制被抑制。然而，在长期治疗过程中，合并感染患者同样面临药物选择耐药变异的问题。研究发现，约15-32%的合并感染患者接受拉米定夫治疗1年后出现拉米定夫耐药HBV。据推测，接受高活性抗逆转录病毒治疗（HAART）的患者可能更容易发展成进展性肝病。

To counteract lamivudine resistant HBV infection in these patients the use of adefovir dipivoxil was tested. In a recent study, 35 patients receiving 150 mg/day of lamivudine as part of their current anti-HIV regimen were treated with 10 mg/day of adefovir dipivoxil for 144 weeks (24). The mean decrease of the serum HBV DNA was of 5.08, 4.25 and 3.86 logs at week 48, 96 and 144 respectively, suggesting a good efficacy of adefovir dipivoxil against lamivudine-resistant HBV. No adefovir-associated resistance mutations in HBV DNA polymerase or HIV-1 reverse transcriptase were detected. So, long-term treatment with adefovir dipivoxil for 144 weeks was well tolerated and resulted in significant and sustained reductions in HBV DNA and ALT in HIV/HBV co-infected patients. Efficacy increased with treatment duration, with no loss of viral suppression. In these HIV/HBV coinfected patients, the superior efficacy of tenofovir over adefovir was also shown or suggested by several studies (22, 172, 337). The data on entecavir use in HBV/HIV co-infected individuals are conflicting. While the drug was not thought to be active against HIV (152), a recent report has highlighted that it can produce 1 log reduction in plasma HIV-RNA and occasionally select for mutation M184V in HIV (143, 237). However, another report has not confirmed this observation in an individual with HIV/HBV/HDV coinfection, in whom ETV did not cause any significant change in plasma HIV-RNA nor selected for the M184V mutation in HIV after more than 24 weeks of treatment (311). Therefore, further research is needed to elucidate the potential clinical relevance of any anti-HIV activity of ETV at the doses currently approved for treating HBV. In the mean time, a warning from the FDA has alerted against the use of ETV in HIV-coinfected patients in the absence of antiretroviral therapy. This recommendation, however, has been made in the absence of information about potential interactions of ETV with antiretrovirals, and specially with abacavir, which is another guanosine analog and might be subject to inhibitory competition phenomena (15).

　　为了治疗患者拉米夫定耐药HBV感染，用阿德福韦治疗进行了检测。在最近的一项研究中，35例患者接受拉米夫定治疗150mg/d，用于抗HIV治疗的同时，接受阿德福韦治疗10mg/d，治疗144周(24)。治疗第48周，第96周和第144周时，血清HBV DNA平均降低值分别为5.08，4.25 和3.86 logs，这提示阿德福韦酯用于治疗拉米夫定耐药HBV感染有较好的疗效。在HBV DNA聚合酶区或HIV-1逆转录酶区，均未检测到与阿德福韦相关的耐药变异。因此，用阿德福韦酯进行144周的长期治疗，患者耐受好，并且在HIV/HBV合并感染患者中引起HBV DNA 和ALT明显持续的下降。随着治疗时间延长，疗效也在增加，且不会失去对病毒的抑制作用。一些研究也显示或提示，在HIV/HBV合并感染的患者中，替诺福韦的疗效优于阿德福韦(22, 172, 337)。恩替卡韦用于治疗HBV/HIV合并感染患者的研究数据不一致。虽然该药被认为没有抗HIV活性时(152)，但近来的一份报告指出，它可以使血浆HIV-RNA降低1log, 并且偶尔可发生HIV M184V选择变异 (143, 237)。然而，另一份报告却没有在HIV/HBV/HDV合并感染患者中证实此观察结论。该病人在恩替卡韦治疗超过24周后，并没有引起任何明显的血浆HIV-RNA变化，也没有发生HIV M184V选择变异(311)。因此，需要进一步研究来阐明在目前允许剂量下，恩替卡韦治疗HBV的同时抗HIV作用的潜在临床相关性。同时，FDA警告反对在没有抗逆转录病毒治疗时对HIV合并感染病人使用恩替卡韦治疗。然而，这种建议是在缺乏恩替卡韦与抗逆转录病毒药物潜在相互作用的信息下做出的，特别是与阿巴卡韦的相互作用，阿巴卡韦是另外一种鸟嘌呤核苷类似物，并且二者之间可能存在竞争性抑制现象(15)。

Hsin-Yun Sun, M.D. Entecavir Should Not Be Used for HBV Patients Co-Infected with HIV. 2008

Review Article: Hoffman, C., Thio, C. Clinical Implications of HIV and Hepatitis B Co-infection in Asia and Africa. The LANCET Infectious Diseases 2007; Vol.7, Issue 6, 402-409.

Co-infection HBV and HCV: Coinfection with HBV and hepatitis C virus is associated with a more severe liver disease (380), increased frequency in the development of hepatocellular carcinoma, and, in respect with therapy, resistance to standard regimen of IFN-gamma (58). IFN has been the most studied agent in treatment of coinfected patients because of the wealth of experience with this agent in viral hepatitis and its proven activity against both viruses. One of the first case reports of successfull treatment with IFN of a coinfected patient was published by Burt et al. in 1993 (32). Utili et al. (335) studied a cohort of 32 HBV/HCV coinfected patints, 16 of whom received IFN treatment (5MU TIW for 12 months). They report an overall sustained virological response rate of 43.8% for HCV infection, and this rate was increased in patients who were HBeAg negative (66.7%). Loss of HBeAg occured in 2 of 13 patients (15.4%). Villa et al. (344) conducted a larger prospective randomized trial of 30 patients with HBV/HCV coinfection (HBsAg-positive, Anti-HCV-positive, HCV RNA-positive), in which patients received either 6 or 9 MU alpha-interferon three times a week for 6 months. This study found that higher dose IFN was more effective in inducing clearance of HCV RNA (31.2 vs 0%, p=0.045), and HBV DNA (100% vs 0%), as well as inducing a sustained biological response (37.5% vs 0%, p=0.019) compared to the lower dose.

HBV和HCV混合感染：HBV和HCV混合感染与更严重的肝病有关(380)，增加了肝细胞癌的发生率，在治疗上对IFN-γ的标准疗法具有抗性(58)。IFN是研究最多的药物，因为IFN治疗病毒性肝炎的经验已经很丰富，而且已经证实对这两种病毒均有活性。1993年被Burt等报道了第一例IFN成功治疗混合感染患者 (32)。Utili 等研究了一组32例HBV/HCV混合感染患者，其中16例接受IFN治疗（5MU ，每周3次，治疗12个月）。该报告显示HCV感染总的持续病毒学答应率为43.8%，并且该数值在HBeAg 阴性患者中增加(66.7%)。13例患者中有2例 HBeAg消失（15.4%）。Villa等(344)进行了更大规模的前瞻性随机研究，他们以30例HBV/HCV混合感染患者（HBsAg阳性, 抗HCV阳性, HCV RNA阳性）为研究对象，患者接受6MU，或9MU α-干扰素治疗，每周3次，治疗6个月。该研究发现高剂量IFN能更有效地清除HCV RNA（31.2 /0%，p=0.045）和HBV DNA（100%/0%），并且与低剂量的IFN相比，还会产生持续的生物学答应 (37.5% /0%，p=0.019)。

Several groups have published studies addressing treatment of coinfected patients with antiviral combination therapy with IFNα (2a or 2b) plus ribavirin (57, 151, 211). Results demonstrated the effectiveness of combined IFN and ribavirin in coinfected patients, with a rate of sustained virological and biological response comparable to HCV monoinfected patients (57, 211). In these studies, viral interaction was evident, in that coinfected patients who achieved a sustained virological response were less likely to achieve HBV DNA clearance, and more likely to have reactivation of HBV or HBV flares. Of the patients who cleared HBV DNA, most did not achieved a sustained virological response with undetectable HCV RNA following combination therapy (57).

　　一些研究人员已经对合并感染患者用IFNα （2a或2b）和利巴韦林进行抗病毒联合治疗研究，并发表了他们的研究结果(57, 151, 211)，结果证实了IFN和利巴韦林联合使用对合并感染病人的疗效，与单一HCV感染患者相比(57, 211)，其病毒学的和生物学的应答率持续性相当。在这些研究中，病毒之间的相互作用是明显的。获得持续病毒学应答率的合并感染患者较少可能出现HBV DNA 清除，而更容易出现HBV重新激活或HBV活动。在接受联合治疗后HBV DNA被清除的患者，继续治疗后大多数没有获得针对HCV的持续病毒学应答（HCV RNA未检测到）(57)。

One study of lamivudine therapy in addition to IFN for coinfected patients has been published by Marrone et al. (228), suggesting that the addition of lamivudine to IFN may be effective in these coinfected patients.

　　Marrone等(228)发表了对IFN与拉米夫定联合治疗混合感染患者的研究，结果表明IFN联合拉米夫定治疗可能对这些混合感染的病人有效。

Co-infection HBV and HDV: Patients persistently infected with both HBV and HDV develop chronic hepatitis with progressive liver disease more severe than that with chronic HBV infection alone (36). Cirrhosis with liver failure occurs in 25%, and hepatocellular carcinoma in 35% of these patients. Interferon-alpha in high dose monotherapy for 1 year remains the only therapeutic option for this group of patients, as lamivudine monotherapy (185) and combination of IFN and lamivudine (361) do not show significant efficacy (94).

HBV和HDV混合感染：持续感染HBV和HDV的患者比单一HBV慢性感染的患者发展成慢性进展性肝脏疾病更严重(36)。这些病人中，肝硬化并肝衰竭发生率为25%，肝细胞癌发生率为35%。由于拉米定夫单药治疗(185)和IFN与拉米夫定联合治疗(361)没有显著的疗效差异，对这些患者而言，高剂量α-干扰素治疗1年仍是唯一的治疗选择(94)。

Liver Transplantation

Liver transplantation is a treatment option for end stage disease. However cirrhosis associated with chronic HBV infection, is a controversial indication for the liver transplantation because of the very high risk of reinfection rate of the hepatic allograft and rapid progressive liver disease in the allograft. Indeed, in patients positive for HBeAg or HBV DNA, the incidence of reinfection is over 80% (286, 288). With HBV reinfection the 1-and 3-years survival rates are 68% and 44% respectively (289). These rates are significantly below those for patients transplanted for other liver diseases. The clinical course of HBV infection in the hepatic graft is accelerated, and liver failure can occur in a short period time. An unusual form of rapidly progressive liver injury characterized by very high levels of hepatitis B antigen expression in hepatocytes, with marked cholestasis and brosis of the transplanted liver develops in 10-20% of patients. This condition, known as fibrosing cholestatic hepatitis or cytolytic hepatitis, is virtually 100% fatal (188, 219); patients do not respond to IFN therapy, and retransplantation is rarely of benefit (69). For these reasons, many liver transplant centers did not consider until recently patients with HBV-induced cirrhosis with ongoing viral replication to be suitable candidates for transplantation. Several options are now available to prevent reinfection of hepatic allograft after liver transplantation.

肝移植

　　肝移植是终末期待肝病的一种治疗选择。然而，就慢性HBV感染相关肝硬化来说，是肝移植的一个具有争议性的指征，因为肝移植后再感染风险很高，并且移植肝脏可以出现快速进展性肝病。事实上，在HBeAg或HBV-DNA阳性的患者中，再感染率超过80% (286, 288)。HBV再感染者1年及3年的生存率分别为68%及44%(289)，明显低于那些因其他肝脏疾病而进行肝移植的患者的生存率。移植肝的HBV临床感染进程会加速，并且会在短期内可发生肝衰竭。10-20%的患者会发生一种少见形式的急性肝损伤，主要表现为肝细胞内乙型肝炎抗原高水平表达,明显的胆汁淤积和纤维化。这种情况被称为纤维化性淤胆性肝炎或溶细胞性肝炎，致死率达到100%(188, 219)，IFN治疗无应答患者，再次肝移植基本上无意义(69)。基于这些原因，许多肝移植中心都不认为乙肝病毒感染引起的肝硬化伴体内病毒持续复制的患者是适宜做肝移植术的，直到最近才有改观，有几种治疗方案可以预防肝移植术后的再次感染。

Hence, the advent of long-term hepatitis B immune globulins (HBIg) administration as a prophylaxis of HBV recurrence has been a major advance in the management of liver transplantation for HBV infection. HBV recurrence has been reduced from over 80% to 20-35% in HBV cirrhotic patients with low level viral replication pre-transplant, but remained high, 30-80% in HBV cirrhotic patients with high HBV replication (184, 287, 289). The drawbacks of HBIg administration are the cost of the long-term administration, the need for a close monitoring to adapt the frequency of readministration depending on the anti-HBs levels, and high recurrence rate in patients with high HBV replication levels. Patients receive 100 ml of HBIg intravenously during the ahepatic phase, and 5 ml of HBIg daily for 1 week after liver transplantation. During the initial few months posttransplantation, anti-HBs titers should be maintained in the 300 to 500 IU/ml range. With this high level of anti-HBs, HBsAg often disappears from the blood. HBIg treatment has to be continued indefinitely, and 5 ml of HBIg should be given whenever the anti-HBs titer declines to 100 IU/ ml. HBIg treatment adds substantial cost to the liver transplantation procedure. HBsAg mutants can develop during maintenance HBIg treatment (328), and occur more commonly with monoclonal HBIg immunoprophylaxis. A recent study by Galun et al (2002) showed promising results using a mixture of two monoclonal antobodies in a phase I clinical study (109). Patients developed a rapid and significant decrease in HBV-DNA levels. Future studies are warranted, but this preliminary data suggests that monoclonal antibody preparations could replace the current polyclonal HBIg.

　　因此，把长期使用乙型肝炎免疫球蛋白（HBIg）作为预防HBV复发的主要治疗方案使肝移植术后HBV二次感染的防治向前迈进了一大步。肝移植术前体内病毒复制水平低的乙肝后肝硬化患者肝移植术后的二次感染率已经由高于80%降到20-35%(184, 287, 289)，而在移植前病毒高水平复制的患者依然很高，为30-80%。长期应用HBIg亦有许多缺陷，例如费用太高，并且需要严密的监测抗HBs滴度来确定再次用药的频率，另外对于体内HBV高复制水平的患者来说，复发率也很高。患者在肝移植术前静脉注射100ml HBIg，肝移植术后1周内每天静脉注射5ml HBIg。肝移植术后最初几个月内，抗HBs滴度将维持在300-500IU/ml。由于抗HBs滴度的水平较高，表面抗原常常随之消失。HBIg的用药时程是持续无限期的，一旦抗HBs滴度下降到100IU/ml，就应该给予5ml。HBIg应用给肝移植手术增添了附加费用。持续应用HBIg治疗可能产生HBsAg变异(328)，尤其是长期应用单克隆HBIg进行免疫预防。Galun等(2002)最新研究显示了在临床研究的一期应用两种单克隆抗体的混合物进行治疗的乐观前景(109)，患者体内的HBV-DNA水平会在短期内明显下降。进一步的研究仍然是有必要的，但是初期资料显示了单克隆抗体制剂可以取代多克隆HBIg。

As lamivudine is well tolerated and controls viral replication in cirrhotic patients, attempts to prevent HBV recurrence were made using lamivudine monotherapy pre-and post-transplant (121). However, an overall recurrence rate of only 40% was observed in a recent multicenter study (272), suggesting that lamivudine used alone was only partially effective. Moreover, lamivudine resistant mutants arise in 20% of liver transplant patients and may be associated with acute liver graft failure (245, 246). Other studies with lamivudine monotherapy have also been disappointing with high rates of HBV recurrence ranging from 23-50% of patients (246, 343).

　　由于拉米夫定在肝硬化者有良好的耐受性并可以控制制体内的病毒复制，人们正试图在肝移植术前及术后采用拉米夫定单药治疗来预防HBV感染的复发(121)。然而，最近的一个多中心的研究发现总体复发率40%(272)，提示拉米夫定单药治疗仅部分有效。而且，20%的肝移植患者会出现拉米夫定耐药变异，这可能与肝移植术后急性肝衰竭的发生有关(245, 246)。其他有关拉米夫定单药治疗的研究结果也令人失望，复发率在23-50% (246, 343)。

Several groups have developed a rationale strategy that combines lamivudine monotherapy pre-transplantation to decrease viral load and lamivudine plus HBIg post-transplantation. In these studies the HBV recurrence rate was less than 10% one to two years following transplantation (8, 110, 227, 229, 297), and the need for HBIg was reduced most likely by a decreased production of HBsAg. These studies clearly indicate that the latter approach is more effective in preventive HBV recurrence, but the optimal duration of prophylaxis remains to determine. Furthermore, by controlling viral replication with lamivudine pre-transplantation, it is now possible to transplant those cirrhotic patients with high HBV replication who were previously removed from the waiting list. An interesting study has shown that in patients with HBIg prophylaxis alone and low HBV replication, the substitution of HBIg by lamivudine administration is equally effective at one year (249). The long-term outcome of these patients needs to be studied and the optimal protocol of prophylaxis needs to be determined before changing the currently validated protocols.

　　一些研究小组提出了一种合理的联合治疗策略，即在肝移植术前使用拉米夫定单一疗法来减少病毒载量，而术后则使用拉米夫定与HBIg联合治疗。这些研究显示术后1-2年的复发率低于10%(8, 110, 227, 229, 297)，而且HBIg的用量随着HBsAg滴度的降低而减少。这些研究明确显示了后一种疗法能更有效的防止复发，但是最佳的预防用药疗程还有待明确。而且，在肝移植术前使用拉米夫定来抑制乙肝病毒在肝硬化患者体内的复制，使以前因为体内乙肝病毒高复制而排除在移植名单之外的肝硬化患者可能接受移植。一项有意义的研究结果显示，对于体内病毒复制水平较低并且使用HBIg单一治疗的患者来说，用拉米夫定来替换HBIg进行治疗后一年之内的疗效是相同的(249)。但是这些患者的长期效果仍需进一步进行研究，而且在改变目前有效的预防方案之前必须先确立最佳方案。

Due to the high number of patients who develop resistance to lamivudine, several large studies have shown the utility of adefovir in the pre and post liver transplantation setting. The largest study by Schiff et al. showed that among patients with lamivudine-resistant HBV and who were pre-OLT, 81% achieved undetectable serum HBV DNA. Furthermore, serum ALT, albumin, bilirubin and prothrombin time normalized in 76%, 81%, 50% and 83% of these pre-OLT patients respectively. Unlike the use of lamivudine, no resistance was identified after 48 weeks of therapy in this population (292). Another study describing the use of prophylactic adefovir was from Lo et al.. They describe 16 patients who had developed YMDD mutations while on the waiting list for OLT. Eleven patients received adefovir for a median of 20 days before transplantation while 5 patients started the drug at the time of OLT. Lo’s cohort was divided in half:eight patients received HBIg (in addition to adefovir and lamivudine) for a median of 24 months whereas the other 8 patients received prophylaxis with adefovir and lamivudine alone. All 16 patients cleared the HBV DNA and had no evidence of recurrence; furthermore, all remained HBeAg negative. The graft survival was 94% at a median follow-up of 21 months. Lo concludes that add-on adefovir plus lamivudine should be the “preferred approach in those patients who have already developed resistance to lamivudine, so as to avoid the emergence of multiresistant viral strains” (212). But it is expected that the development of adefovir mutations may become a problem in the post-transplant setting. Villeneuve et al. recently reported the first case of a patient who developed sequential selection of lamivudine and adefovir resistant strains of HBV in a liver transplantation patient (346).

　　由于很多病人对拉米夫定发生耐药，人们开始研究在肝移植术前及术后使用阿德福韦酯的预防疗效。其中最大的研究来自Schiff等人，结果显示在体内产生拉米夫定耐药HBV并且接受肝移植的患者当中，约81%的患者经阿德福韦酯治疗后血清HBV DNA检测不到。而且这些患者的血清ALT，白蛋白，胆红素和凝血酶原时间正常化的比率分别为76%,81%,50%,83%。与拉米夫定不同，使用阿德福韦酯治疗48周之后，患者体内并没有检测出耐药病毒株(292)。另一项有关阿德福韦酯预防疗效的研究来自于Lo等人。他们研究了16名等待肝移植但产生YMDD突变株的患者，其中11名患者平均在肝移植术前20天应用了阿德福韦酯，其余5名患者在肝移植时开始应用阿德福韦酯。Lo的研究对象平分为两组：8名患者接受两年的乙肝免疫球蛋白治疗(除此之外加上阿德福韦酯及拉米夫定)，另外8名患者只接受阿德福韦酯与拉米夫定治疗，结果显示所有患者体内的乙肝病毒DNA均被清除，且无复发迹象，而且HBeAg均持续为阴性，这些肝移植患者术后21个月中位随访时间的生存率为94%。Lo认为对于已经产生拉米夫定耐药病毒株的患者，为了避免多重耐药病毒株的产生，在拉米夫定基础上加用阿德福韦酯是比较理想的疗法(212)。然而人们预期肝移植术后阿德福韦酯耐药病毒株的产生将会是另一个难题。Villeneuve等人最近报道了第一例肝移植术后产生拉米夫定与阿德福韦酯耐药病毒株的患者(346)。

Tenofovir was also tested for the treatment of patients with HBV recurrence following liver transplantation. In 2004, Neff et al reported 16 patients who developed a resistance to lamivudine following OLT (252). Half of these patients received tenofovir at a dose of 300mg/day 1-66 months after the development of resistance. Therapy was continued for 14-26 months . All the patients experienced viral DNA suppression with 7 having undetectable viral loads.

　　人们也研究了替诺福韦预防肝移植术后乙肝复发的临床疗效。Neff等人在2004年报道了16例产生拉米夫定耐药的肝移植患者(252)。其中半数病人在产生耐药后的1-66个月内应用替诺福韦300mg/d治疗，该治疗持续了14-26个月。所有患者乙肝病毒DNA复制都受到抑制，7例患者病毒载量达到不可检测的水平。

It is expected that entecavir will be also efficacious in the prevention and treatment of recurrent HBV following liver transplantation.

　　预期恩替卡韦也能有效预防肝移植后乙肝复发。

In the recent years, the development of new nucleoside analogs has clearly improved the management of liver transplantation for HBV liver disease. The use of antivirals pre-transplantation, followed by the combination of antivirals and HB Ig post-transplantation allowed to decrease significantly the risk of HBV recurrence on the liver graft, and to decrease dose of HB Ig to maintain high levels of antibodies.

　　总的来说，近年来新的核苷类似物的出现已经明显的改善了乙肝后肝硬化患者肝移植术后临床效果。术前应用抗病毒药物，术后联合应用抗病毒药物与HBIg的治疗方案明显降低了肝移植术后的乙肝复发率，并且在减少了HBIg的用药剂量的基础上，维持了抗体的高水平。

Review Article: Lok ASF, McMahon BJ. Chronic Hepatitis B. AASLD Practice Guidelines. Hepatology 2007:45;507-539.

Review Article: Sorrell MF, et al. National Institutes of Health Consensus Development Conference Statement: Management of Hepatitis B. Ann Intern Med 2009;150(2):104-10.

(Printable Version of Alternative Therapy for Hepatitis B Virus Special Infections/Undeerlying Diseases)

ENDPOINTS FOR MONITORING THERAPY Guided Medline Search

监测治疗终点

Patients with chronic HBV infection commonly have progressive liver disease and are at risk of developing cirrhosis or hepatocellular carcinoma. The primary goal of antiviral therapy for chronic HBV infection is elimination of virus from all host cells, and the ideal response to therapy would be loss of all HBV markers with the appearance of anti-HBs. This has proven to be difficult but not an impossible challenge. An alternative and pragmatic approach is be to control HBV replication and prevent progression of liver disease. Antiviral therapy may result in loss of HBV DNA and HBeAg and normalization of transaminases without clearance of HBsAg. HBV DNA can integrate into the host cell DNA and may continue HBsAg production without producing infectious virus. Integrated HBV DNA is not likely to be eliminated by antiviral therapy, and may be one of the main factors involved in hepatocellular carcinoma development despite successfull therapy.

　　慢性乙肝病毒感染的病人通常有进展性的肝病并有发展成肝硬化或肝癌的危险。慢性乙肝病毒感染抗病毒治疗最主要的目标是从宿主所有细胞中清除病毒，最理想的治疗是将一切HBV标志物消失并且出现HBsAb，这已被证明是十分困难的，但并非不可能的挑战。现实的替代方案是控制乙型肝炎病毒复制并防止肝脏疾病的进展。抗病毒治疗虽然不能清除HBsAg但可以使HBV DNA及HBeAg消失和转氨酶正常化。HBV DNA能整合到宿主细胞DNA，持续产生性HBsAg而不产生具有传染性的病毒。抗病毒治疗看来并不能清除整合的HBV DNA，所以即使治疗成功它还是导致肝细胞癌发生的主要因素之一。

VACCINES Guided Medline Search

疫苗

Indications

适应症

Pre-exposure Vaccination to Prevent HBV Infection: As infants who are exposed to HBV infection are also exposed to a high rate of chronicity of HBV infection, hepatitis B vaccination is recommended for all infants. Vaccination should start during the newborn period with a usual schedule.

暴露前接种疫苗预防HBV感染：由于婴幼儿容易感染乙肝病毒，并且感染后容易慢性化，因此推荐所有的婴儿进行乙型肝炎疫苗接种。疫苗接种应开始在新生儿时期，并制定一个通用的时间表。

Special efforts should be made to ensure a complete vaccination schedule during the first year of life in highly endemic areas. All children and adolescents not previously vaccinated should be vaccinated with the appropriate dose of vaccine according to age. This is especially important as HBV is very efficiently transmitted via sexual route.

　　在疾病高发地区，尤其在婴儿第一年，应努力确保一个完整的预防接种时间表实施。所有以前未接种疫苗儿童和青少年都应按年龄接种适当剂量的疫苗，这一点尤其重要，因为乙肝病毒非常容易由性途径传播。

People belonging to high-risk groups should be vaccinated with the age appropriate vaccine dose and schedule. They are i) sexually active heterosexuals with multiple partners or past-history of sexually transmitted diseases, ii) homosexuals and bisexuals, iii) household contacts and sexual partners of HBsAg carriers v) intra-venous drug users, v) people with occupational risk of HBV infection (health care workers in any field, public safety workers) vi) patients and staff of institutions for the disabled vii) hemodialysis patients, viii) patients who receive blood derived products such as clotting factors, ix) adoptees from highly endemic countries, x) international travelers xi) long-term inmates. Most of these persons should be tested for HBsAg prior to vaccination and should have post-vaccination test for anti-HBs antibody to ensure efficient prophylaxis.

　　高危人群都应按照年龄和时间表接种适当剂量的疫苗。高危人群包括：1）有多个异性性伙伴或既往有性传播疾病者，2）同性恋和双性恋者，3)有家庭接触史或兴伴侣是HBsAg携带者，4)静脉吸毒者， 5) 从事HBV感染的高危职业者（任何领域的卫生保健工作者、负责公共安全的职员），6）病人及伤残机构的工作人员，7）血液透析患者，8）需要血液或血液制品（如凝血因子）者，9）来自高流行国家者，10）国际旅游者。11）长期居民。这些人在接种乙肝疫苗前应该检测乙肝表面抗原，并在接种后检测是否有乙肝表面抗体以确保达到有效的预防目的。

Post-Exposure Prophylaxis to Prevent HBV Infection: Prevention of perinatal infection is a major goal for public health, as the rate of transmission and of chronicity of viral infection in newborn from chronically infected mothers reaches 90%. All pregnant women should be tested for HBsAg during prenatal visit in each pregnancy. Pooled serum from patients who have recovered spontaneously from acute HBV and who have significant anti-HBs titers can be used for passive immunization. These hepatitis B immune globulins (HBIg) are administered simultaneously with HBV vaccine to newborn infants whose mothers are HBsAg positive (6, 342, 378). Administration of HBIg vaccine therapy is most effective if given within 12 hours of birth (342). They should receive the complete schedule of vaccination and should be tested for HBsAg and anti-HBs following the completion of vaccination at approximately one year of age.

暴露后预防乙肝病毒感染：预防围产期感染是公共卫生的一个主要目标，因为慢性乙肝病毒感染母亲传染给新生儿并使其慢性化的几率可达90 ％。因此所有孕妇都应该在产前做HBsAg检测。库存急性乙型肝炎自然恢复者和具有较高抗HBs滴度者的血清可用于被动免疫。对于母亲是HBsAg的新生儿应给予乙型肝炎免疫球蛋白（HBIG）并同时注射乙肝疫苗(6, 342, 378)。在分娩后12小时内给予HBIG和疫苗疗法是最有效的(342)。应该按照时间表给予新生儿完整的疫苗接种，并在大约1岁时检测HBsAg和HBsAb。

In populations in which the screening of pregnant women for HBsAg is not feasible, all infants should receive the first dose of vaccine during the first 12 hours of life followed by a second dose at 1 month, and a third at 6 months. In this setting the use of HBIg is not indicated.

　　在一些人群对所有孕妇进行乙肝表面抗原筛查很难实现，因此对所有的婴儿在第一次12小时内，在1个月、在6个月分别接种一次乙肝疫苗。在这种情况下没有指征使用HBIG。

People who have been exposed (e. g. accidental percutaneous or permucosal exposure), or potentially exposed (e. g. suspect sexual intercourse) to HBV, should be first tested for HBsAg and anti-HBs markers. If the exposed person is not vaccinated, he should receive HBIg at 0.06 mL/kg intramuscularly together with the first dose of vaccine. If the exposed person was vaccinated and known to be a responder to the vaccination, one may consider a booster vaccination, but no HBIg administration. If he was known to be a non-responder to the vaccine, one may consider either the administration of HBIg at double dose or HBIg plus vaccination.

　　对那些已经暴露（例如意外经皮或者经粘膜暴露）或有潜在暴露（例如可疑性交）于乙肝病毒的人，首先应该检测HBsAg与抗-H Bs血清标志物。如果暴露者是以前没有注射乙肝疫苗，应该按0.06ml/kg体重肌注HBIG同时给予首次剂量的疫苗。如果暴露者已经接种过疫苗，并有应答，可以考虑加强注射一次疫苗，但不用给予HBIG。如果暴露者已知对乙肝疫苗没有应答，可以考虑给予两倍剂量的HBIG或HBIG加上乙肝疫苗。

Dose and Schedule

剂量和时间表

The currently used HBV vaccines consist of the small envelope (S) protein, and the middle pre-S2 envelope (M) protein in European vaccines, assembled into 22 nm particles. Both the S and M proteins contain the HBsAg which consists of the common “a” determinant and several subtype determinants (GenHevac-B vaccine, Aventis-Pasteur). S vaccines are produced by processing of HBsAg purified from plasma of HBV carriers as well as from yeast cells (Saccharomyces cerevisiae) expressing recombinant DNA (Engerix-B, GSK and Recombivax-HB VAXII, Merck). The M/S vaccine is a recombinant vaccine prepared by expression in CHO cells.

　　目前在欧洲使用的乙肝疫苗是由小外膜蛋白（S）和中等大小前-s2外膜蛋白（M）组装成的直径22 nm的颗粒。无论是S和M蛋白都含有乙肝表面抗原组成的共同“a ”决定簇和几个亚型的决定簇（ genhevac - B疫苗， Aventis公司-巴斯德）。 S疫苗是从HBV携带者的血浆或者从表达重组DNA的酵母细胞（酿酒酵母菌）中分离纯化HBsAg的（ Engerix-B，葛兰素史克和Recombivax-HBVAXII，默克公司）。M/S疫苗是在中国仓鼠卵巢细胞中表达制备的重组疫苗。

These vaccines are administered by the intramuscular route in the deltoid and are highly immunogenic, inducing a protective anti-HBs antibody titer (> 10 IUper ml) in more than 95% of healthy children or young adults (4, 189, 340). Two schedules of administration are approved: 1) 3 initial injections at one month intervals and a booster at month 12; 2) 2 initial injections one month apart followed by a booster at month 6 (Table 9). About 5% of those vaccinated fail to respond with development of antibodies to the vaccine. Several factors of non-response have been identified, including genetically determined non-responsiveness, age over 40 years, high body mass index, and immuno-suppression (4, 189, 340). The HBV vaccine is associated with rare side effects, most commonly pain or soreness at the injection site. Neurological disorders such as multiple sclerosis, Guillain-Barré syndrome, and transverse myelitis have not been causally linked to the HBV vaccine (9, 66).

　　这些疫苗通过三角肌肌内注射，具有高度免疫原性，可以在95 ％以上的健康儿童或青少年人诱导产生保护性HBsAb（滴度> 10IU/dl）(4, ｋ, ｋ)。目前有两种时间表得到认可：1）前三针每隔一个月注射一次，并在十二个月时加强一针。2）前两针每隔一个月注射一次并在第6 月时加强注射一次(表 9)。大约5 ％接种疫苗的人不能产生抗体，明确的有以下几种因素：遗传因素、年龄大于40岁、高体重指数及免疫抑制(4, 189, 340)。乙肝疫苗副作用是很罕见的，最常见的是注射部位疼痛或酸痛。尚未有证据证明神经疾患如多发性硬化症、格林-巴利综合征、横断性脊髓炎的发生与乙肝疫苗有关(9, 66)。

The efficacy of protection against HBV infection has been proven in large clinical studies of exposed populations such as homosexual men, healthcare workers, and infants born to HBsAg positive mothers (4, 189, 340). In these clinical studies, the protection was evident when anti-HBs Ab titers were above 10 IUper ml. Several years after vaccination, the anti-HBs Ab titer may decline to undetectable level but immunity against clinical disease persists for years, suggesting the existence of an immunological memory (4, 189, 340). Based on these results, a booster is not recommended in healthy individuals who are not exposed to a high risk of HBV infection. Protective levels are obtained in 95% of infants born from negative mothers, adolescents and adults (Table 10). In newborns from chronically infected mothers, the effectiveness of hepatitis B prophylaxis exceeds 75%. Immunity following vaccination is lasting and there is no recommendation by W. H. O. for routine booster revaccination. Indeed specific anti-HBs immunity persists based on immunologic memoric and capability for rapid anamnestic anti-envelope response, even when anti-HBs have disappeared long after vaccination.

　　大量的临床研究表明乙肝疫苗对暴露人群，如男同性恋者、医疗保健工作者、母亲为乙肝表面抗原阳性的新生儿有较好的保护作用(4, 189, 340)。在这些临床研究中，抗HBs抗体滴度大于10IU/ml时保护作用是显而易见的。接种疫苗数年后，抗HBs抗体滴度可能下降到不能检测的水平，但对临床疾病免疫力仍能持续多年，提示可能存在免疫记忆(4, 189, 340)。基于这些研究结果，对于HBV感染暴露高度风险的健康人不推荐疫苗的加强接种。通过接种可以使95％的母亲为HBsAg阴性的新生儿、青少年及成年人获得保护(表 10)。对于预防母亲是慢性乙肝感染的新生儿的有效率超过75％。接种疫苗后的免疫力是持久的，WHO没有推荐常规加强疫苗接种。事实上，即使在接种疫苗很长时间后HBsAb消失，基于免疫记忆和对快速的记忆性抗包膜反应能力的特异性抗HBs免疫仍持续存在。

Vaccine escape mutants have been reported in follow-up studies of individuals receiving HBsAg vaccines composed of the S protein. Vaccine escape mutants can differ from wild-type by only a single nucleotide change in the “a” determinant. Vaccination probably does not totally block infection of the liver following exposure. Rather, spread of virus from infected hepatocytes is probably restricted by antibodies until the cellular immune response can destroy the infected cells. In immunocompetent individuals, spread of the rare vaccine escape variants in an inoculum would presumably be controlled by the cellular immune response as well as by antibodies to the altered S protein. Therefore, vaccine escape is still rare, most typically seen in patients who, if not vaccinated, would have been at high risk of developing chronic infection after exposure to HBV; that is, young children, or immunocompromised adults. It is rarer in healthy adults presumably because they are at low risk of developing chronic infection in any case. Vaccine escape mutants may fail to be detected by some diagnostic tests for HBsAg, the most common assay for an ongoing HBV infection (60). Most studies of vaccine escape have involved at risk children and infants who were either vaccinated or received vaccine plus HBIg, strongly reactive to the “a” determinant of HBsAg. During the 1980s, a follow-up study of childhood vaccination in Italy revealed vaccinees who became HBsAg positive, despite the presence of a strong antibody response to HBsAg. The incidence was rare, involving about 2% of the children of HBsAg positive mothers, or with HBsAg positive family contacts (38, 374). More detailed analysis of virus from one patient revealed a point mutation encoding a gly145arg substitution at amino acid 145 of the S protein; that is, within the “a” determinant (38). Analysis with monoclonal antibodies to the “a” determinant of wild-type HBV revealed a loss of binding to the mutant HBsAg (38, 355). Subsequent studies in other populations with high HBV endemicity confirmed the rare occurrence of vaccine escape mutants in children, including the glyc145arg substitution in “a”, other substitutions or insertions in “a”, and mutations within the external hydrophilic domain but outside of “a” (39, 102, 148, 150, 159, 192, 258, 364). “Vaccine escape” variants have also been detected in unvaccinated children and adults with circulating virus as well as anti-HBsAg (148, 364), possibly reflecting past or concurrent infection with wild-type and mutant virus. Approaches to deal with vaccine escape variants will be needed as individuals in whom these variants are predominant become an increasing fraction of the pool of HBV carriers (148).

　　在随后的研究中发现接种包含S蛋白的疫苗的个体中发现疫苗逃逸突变体。疫苗逃逸突变体可以仅有“a ”决定簇中的一个单核苷酸与野生株不同。预防接种也许不能阻断暴露肝脏的感染，但是抗体可以阻止病毒从感染细胞蔓延到其他细胞，直到细胞免疫反应可以破坏感染的细胞。在免疫功能正常的个体，这种罕见的疫苗逃逸变异株的传播可能通过细胞免疫应答或者变化了的S蛋白的抗体被控制。因此，疫苗的逃逸是罕见的，但是对于没有接种过乙肝疫苗的病人在暴露于乙肝病毒后发展为慢性感染的几率非常高，这包括幼儿及免疫功能低下的成年人。在健康成人这种免疫逃逸更为罕见，因为任何情况下他们发展为慢性感染的风险都非常低。目前常用的检测乙肝病毒感染的一些诊断性试验可能检测不到乙肝疫苗突变体(60)。大量关于疫苗逃逸的研究表明，不管是接种过疫苗还是接种疫苗和HBIG的婴幼儿和儿童高危风险性与HBsAg的“ a ”决定子有明显的相关性。在20世纪八十年代，意大利学者对儿童疫苗接种的随访研究中发现，尽管接种疫苗者机体存在很强的抗体反应，但仍有为HBsAg阳性者。虽然这种发生率很小，其中包括约2 ％母亲为HBsAg阳性或有HBsAg阳性的家庭接触史的儿童(38, 374)。对于一个病人更为详细的研究发现，这是由于病毒编码“a”决定子S蛋白145位氨基酸gly145arg一个点突变导致的(38)。对野生株HBV “a”决定子单克隆抗体的分析表明突变的HBsAg结合力缺失(38, 355)。在对乙型肝炎高发地区的另一人群的后继研究中发现在儿童体内发生的逃逸突变包括在glyc145arg取代“a” ，以及在“a ”位其他的取代或插入，除了在“a”位外，也可在亲水区域外发生突变(39, 102, 148, 150, 159, 192, 258, 364)。在未接种疫苗的儿童和成人中也发现了“疫苗逃逸”突变体(148, 364)，可能反映了过去或现在野生株或突变株病毒感染。随着这些突变体在HBV携带者中越来越占有优势，因此需要对突变体进行处理(148)。

PREVENTION OR INFECTION CONTROL MEASURES Guided Medline Search Smart search

预防或感染控制措施

Even though a vaccine for hepatitis B has been available since the early 1980's, and WHO has made recommendation for large-scale vaccination program, there is still a need to generalize these programs to eradicate this ubiquitous infection. It was clearly shown that the initial vaccination program targeting only high-risk groups failed to affect the overall HBV carrier rate. As the risk of chronicity of viral infection is higher in young children and the efficacy of the hepatitis B vaccine is usually greater in children, it was therefore recommended by W. H. O. to target the population of newborns and children for mass vaccination.

　　尽管从上世纪八十年代开始实施疫苗接种，并且WHO推荐大规模的疫苗接种计划，但仍需普及接种计划以消除普遍存在的乙肝感染。最初的疫苗接种计划仅针对高风险群体明显没有影响整体的HBV携带率。由于慢性乙肝病毒儿童慢性感染率较高及乙肝疫苗在儿童期的效用较好，因此，WHO推荐针对对新生儿和儿童人群进行大规模疫苗接种。

In Taiwan, a large-scale vaccination of all newborns regardless of the status of their mother, started in 1985 (42). In 10 years, this was program was able to decrease the prevalence of HBsAg carriage from 8% to 0.8% in Taiwanese children. Moreover, this was associated with the decrease in hepatocellular carcinoma incidence in children while the incidence of other cancers remained stable over time. The results of this study clearly demonstrated the benefit of HBV vaccination at the scale of a country.

　　在台湾，从1985年开始，无论其母亲是否感染HBV，对所有新生儿进行大规模的疫苗接种(42)。10年来，该计划使台湾儿童HBsAg携带率从8％降至0.8％。此外，随着时间的推移，儿童肝癌的发病率降低，而其它癌症的发病率仍保持稳定。这项研究结果明确显示了在一个国家范围内接种射HBV疫苗的益处。

In Italy, a campaign for hepatitis B immunization of children and teenagers started in 1991. Its impact was determined by the incidence of hepatitis B. It was shown that the hepatitis B incidence declined from 10.4/100000 in 1987 to 2.9/100000 in 1997. The drop in hepatitis B incidence was even more significant after the introduction of mass vaccination (318).

　　在意大利，从1991年发起对儿童和青少年接种乙肝疫苗活动。其作用通过乙型肝炎发病率证明。研究显示，乙型肝炎发病率从1987年的10.4/10万下降至1997年的2.9/10万。大规模疫苗接种后乙型肝炎发病率下降更加显著(318)。

The results of these different studies confirm the prediction that universal immunization of the total world population could bring hepatitis B to a clinically non-relevant disease within a predictable time frame. Different models have also confirmed the cost-effectiveness of universal infant immunization against hepatitis B.

　　不同的研究结果证实预测结果，对全球人口普遍免疫接种，在可预期的时间框架内，可使乙型肝成为一个临床上不重要的疾病。不同研究模型也证实了儿童普遍进行乙肝疫苗接种的成本效益。

Beside large-scale vaccination programs, infection control measures should include the implementation of routine screening for blood donors, pregnant women, health-care workers and people migrating from high endemic areas, and should rely on general population counseling to decrease exposure to HBV. Both non-carriers and HBV-carriers should be widely informed about the disease and its transmissions and therefore should be expected to have a responsible behavior (e. g. use of condoms) in respect with the spread of the infection. Finally, close contacts of HBV-carrier should be tested for HBV infection. If they have not developed HBV infection or immunity to HBV, they should receive HBIg and/or HBV vaccine.

　　除了大规模的疫苗接种计划，感染控制措施应包括对献血者、孕妇、医护人员和高发区迁入居民进行常规筛查，以及对普通人群进行宣教以减少对HBV暴露。应更大程度上使HBV携带者和非HBV携带者了解乙肝这一疾病及其传播途径，并期望他们对自己的行为负责（如使用避孕套）及减少感染扩散。最后，与HBV携带者密切接触者应检测HBV感染。如果他们没有发生HBV感染或对HBV无免疫能力，应该接受HBIg和/或HBV疫苗。

Thompson ND, et al. Nonhospital Health Care-associated Hepatitis B and C Virus Transmission: United States, 1998-2008. Ann Intern Med. 2009. Jan 6;150(1):33-9.

TABLES AND FIGURES

图表

TABLE 1. Natural History and Interpretation of Hepatitis B Markers

表1. 乙型肝炎标志物的自然史和解释

标志物	急性感染	既往感染	慢性
标志物	急性感染	既往感染	免疫耐受	慢性肝炎	前C区变异	不活动携带者
HBsAg	+	-	+	+	+	+
HBeAg	早期+，然后-	-	+	+	-	-
抗HBc-IgM	+	-	-	-	-	-
抗HBc总数	+	+	+	+	+	+
抗HBs	-	+	-	-	-	-
抗HBe	早期-，然后+	+	-	-	+	+
HBV DNA	早期+，然后-	-	+	+	+/-	弱
ALT	增加（高度）	正常	正常	增加（轻中度）	增加（波动）	正常

TABLE 2. Hepatitis B Therapies and Vaccines in Development or FDA-approved

表2. 在研制或FDA批准的乙型肝炎治疗和疫苗

药物名称	药物分类	厂商	FDA地位-美国
Intron A（干扰素α-2b）	干扰素	Schering-Plough	FDA批准（1991年）
Pegasys（聚乙二醇干扰素α-2a）	干扰素	Roche Labs	FDA批准（2005年）
核苷（酸）类似物
Epivir-HBV（拉米夫定；3TC）	核苷类似物	GlaxoSmithKline	FDA批准（1998年）
Hepsera（阿德福韦酯）	核苷酸类似物	Gilead Sciences	FDA批准（2002年）
Baraclude（恩替卡韦）	核苷类似物	Bristol-Meyers Squibb	FDA批准（2005年）
恩曲他滨（FTC）	核苷类似物	Gilead Sciences	Ⅲ期临床
替比夫定（LdT）	核苷类似物	Idenix	Ⅲ期临床
替诺福韦	核苷酸类似物	Gilead Sciences	Ⅲ期临床
克拉夫定（L-FMAU）	核苷类似物	Pharmasset	Ⅱ期临床
艾夫他滨（ACH 126, 443）	核苷类似物	Achillon Pharmaceuticals	Ⅱ期临床
伐托他滨	核苷类似物	Idenix	Ⅱ期临床
氨多索韦（DAPD）	核苷类似物	RFS Pharm	Ⅱ期临床
Racivir	核苷类似物	Pharmasset	Ⅱ期临床
ANA 380（LB80380）	核苷类似物	Anadys	Ⅱ期临床
Pradefovir（Remofovir）	核苷类似物	Metabasis	Ⅱ期临床
Pradefovir	核苷类似物	Valeant	Ⅱ期临床
MIV 210	核苷类似物	Medivir	Ⅰ期临床
Pentacept（L-3’-FD4C）	核苷类似物	Pharmasset	临床前期
非核苷类抗病毒
BAM 205	小分子	Novelos	Ⅱ/Ⅲ期临床
NOV-205（BAM 205）	小分子	Novelos	Ⅱ/Ⅲ期临床（中国）/批准（俄国）
HepeX-B	单克隆抗体	XTL Biopharm	Ⅱ期临床
EHT 899	病毒蛋白	Enzo Biochem	Ⅱ期临床（以色列）
UT 231-B	小分子	United Therapeutics	临床前期
SpecifEx-HepB	免疫细胞转移	Chromos	临床前期/Ⅰ期临床
HepeX-B	快速感染RNA	Nucleonics	临床前期
Bay 41-4109	抑制病毒核衣壳	Bayer AG	临床前期
其它免疫调节剂
日达仙（胸腺肽-α）	免疫刺激剂	SciClone	联合拉米夫定治疗Ⅱ期临床
EP-HBS（HBV治疗性疫苗）	免疫刺激剂	Epimmune	Ⅰ期临床
HBV核心抗原疫苗	免疫刺激剂	Microscience	Ⅰ期临床
暴露后治疗
移植后
Nabi-HB	免疫球蛋白	Nabi	FDA批准（1999年）
Bay-Hep B	免疫球蛋白	Bayers US	FDA批准（1977年）
Anti-Heptitis B	免疫球蛋白	Cangene	FDA补充Ⅲ（2001年）
HBV预防性疫苗
Recombivax HB	乙型肝炎	Merck & Co.	FDA批准
Engerix-B	乙型肝炎	GlaxoSmithKline	FDA批准
Twinrix	甲型和乙型肝炎	GlaxoSmithKline	FDA批准
Pediarix*	乙型肝炎和其它*	GlaxoSmithKline	FDA批准

* Pediarix：一种新的混合疫苗，可防止婴儿感染白喉，破伤风，百日咳，脊髓灰质炎以及乙型肝炎病毒所致疾病。

TABLE 3. Contraindications for Interferon-α Therapy for Chronic Hepatitis B

表3. 干扰素-α治疗慢性乙型肝炎的禁忌症

肝功能失代偿：	-胆红素>51.3µM -白蛋白<30g/L -凝血酶原时间延长>3s
门脉高压：	-静脉曲张出血 -腹水 -肝性脑病
脾功能亢进：	-白细胞减少（<2×10⁹/L） -血小板减少（<7×10⁷/L）
肾损害：	-肌酐>176.8µM
自身免疫性疾病	-结节性多动脉炎 -类风湿性关节炎
严重主要器官功能障碍	-心力衰竭 -呼吸道阻塞疾病 -未控制糖尿病
精神病	-重度抑郁 -自杀倾向
成瘾性	-酗酒 -目前静脉吸毒

TABLE 4. Factors Predictive of Responsiveness/ Nonresponsisveness of Chronic HBV Infection to IFN-α Treatment

表4. 慢性HBV感染对IFN-α治疗应答/无应答预测因素

可能应答者	可能无应答者
HBV DNA载量低（<200pg/mL）	HBV DNA载量高
ALT水平高（>100unit/L）	失代偿期肝硬化患者
活动性肝病（AST>2-5x）	正常ALT/AST
HBeAg阳性	HBeAg阴性（前C区变异）
免疫功能正常	免疫抑制
病程短（<4年）	HIV或/和HDV阳性
成人获得感染	新生儿获得感染
女性	男性
异性恋	同性恋

TABLE 5. Biochemical and Virological Response During Lamivudine Therapy of Patients with Wild Type HBV Infection

表5. 拉米夫定治疗野生型HBV感染患者的生化学和病毒学应答

参考文献	抗HBe血清转换	ALT正常	Knodell评分改善	YMDD变异病毒反弹
治疗12个月
Lai等（1998）	16%/4%（安慰剂）	72%/24%（安慰剂）	56%/25%（安慰剂）	14%
Dienstag等（1999）	17%/6%（安慰剂）	41%/7%（安慰剂）	52%/23%（安慰剂）	32%
Liaw等（2000）	17%	37.5%		14%
Leung等（2001）	22%	22-38%
治疗24个月
Leung等（2001）	27%	29-42%
Liaw等（2000）	29%	42%		38%
治疗36个月
Leung等（2001）	40%	40-65%	69%	53%

TABLE 6. Biochemical and Virological Response During Adefovir Therapy of Patients with HBV Infection

表6. 阿德福韦治疗HBV感染患者的生化学和病毒学应答

参考文献	HBV DNA下降（log₁₀）	抗HBe 血清转换	ALT 正常	Knodell 评分改善	病毒反弹
HBeAg阳性患者：
治疗12周
Zeng等（2006）	3.4/0.1（安慰剂）	6%/5%（安慰剂）	42%/14%（安慰剂）
治疗48周
Marcellin等（2003）	3.52/0.55（安慰剂）	12%/6%（安慰剂）	48%/16%（安慰剂）	53%/25%（安慰剂）
治疗52周
Zeng等（2006）	4.5/0.2（安慰剂）	8%/7%（安慰剂）	79%/21%（安慰剂）
HBeAg阴性患者：
治疗48周
Hadziyannis等（2003）	3.91/1.35（安慰剂）		72%/29%（安慰剂）	64%/33%（安慰剂）
治疗96周
Hadziyannis等（2005）	3.47/1.09（安慰剂）		73%/32%（安慰剂）	89%/50%（安慰剂）	3%
治疗144周
Hadziyannis等（2005）	3.63		69%		5.9%
拉米夫定耐药患者（治疗48周）
Peters等（2004）	4/1.31（拉米夫定）	11%/0%（拉米夫定）	47%/5%（拉米夫定）

TABLE 7. Biochemical and Virological Response During Entecavir Therapy of Patients with HBV Infection

表7. 恩替卡韦治疗HBV感染患者的生化学和病毒学应答

参考文献

HBV DNA下降

（log₁₀）

抗HBe

血清转换

ALT

正常

Knodell

评分改善

病毒

反弹

HBeAg阳性患者（治疗48周）：

Chang等（2006）

6.98/5.46

（拉米夫定）

21%/18%

（拉米夫定）

68%/60%

（拉米夫定）

72%/62%

（拉米夫定）

HBeAg阴性患者（治疗48周）：

Lai等（2006）

5/4.5

（拉米夫定）

78%/71%

（拉米夫定）

70%/61%

（拉米夫定）

拉米夫定耐药患者：

治疗24周：

Chang等（2005）

4.21/0.95

（拉米夫定）

39%/21%

（拉米夫定）

治疗48周：

Chang等（2005）

5.06/1.37

（拉米夫定）

4%/6%

（拉米夫定）

68%/6%

（拉米夫定）

Sherman等（2006）

5.11/0.48

（拉米夫定）

8%/3%

（拉米夫定）

61%/15%

（拉米夫定）

55%/28%

（拉米夫定）

0.014%

（0.071%有基因型耐药）

TABLE 8. Biochemical and Virological Response During Combination Therapy of Patients with HBV Infection

表8. 联合治疗HBV感染患者的生化学和病毒学应答

参考文献	HBV DNA下降（log₁₀）	抗HBe血清转换	ALT正常
拉米夫定+PEG干扰素
Lau等（2005）
治疗48周	7.2/5.8（拉米夫定）和4.5（PEG）	24%/20%（拉米夫定）和27%（PEG）	46%/62%（拉米夫定）和39%（PEG）
治疗48周+治疗后24周	2.7/1.9（拉米夫定）和2.4（PEG）	27%/19%（拉米夫定）和32%（PEG）	39%/28%（拉米夫定）和41%（PEG）
Janssen等（2005）
治疗52周		25%/22%（PEG）	51%/34%（PEG）
治疗52周+治疗后26周		29%/29%（PEG）	35%/32%（PEG）
拉米夫定+阿德福韦治疗拉米夫定耐药患者
治疗48周
Peters等（2004）	3.46/0.31（拉米夫定）和4（阿德福韦）	6%/0%（拉米夫定）和11%（阿德福韦）	53%/5%（拉米夫定）和47%（阿德福韦）
治疗52周
Perillo等（2004）	-4.6/+0.3（拉米夫定）	8%/2%（拉米夫定）	31%/6%（拉米夫定）

TABLE 9. Dosage and Administration Schedules for Pre/Post Exposure HBV-Vaccination

表9. 暴露前/后HBV疫苗的剂量和用法方案

人群	方案	Recombivax	Engerix-B（或Pediarix，或Twinrix）	Genhevac B
婴儿	第0，1，6个月+如需要，第12个月追加	2.5µg	10µg	20µg
婴儿（HBeAg母亲）	出生后12小时内（HBIG+首剂疫苗），然后第1，6个月+如需要，第12个月追加	5µg	10µg	20µg
儿童和青少年	第0，1，6个月+如需要，第12个月追加	5µg	10µg	20µg
成人（身体健康）	第0，1，6个月+如需要，第12个月追加	10µg	20µg	20µg
成人（免疫功能低下）	第0，1，6个月+如需要，第12个月追加	40µg	40µg	40µg
成人（暴露后）	出生后12小时内（HBIG+首剂疫苗），然后第1，6个月+如需要，第12个月追加	10µg	20µg	20µg

Table 10. Performance of Hepatitis B Vaccine

表10. 乙型肝炎疫苗的性能*

疫苗的安全性和有效性

-成年人

总有效率：95%

大约100%抗HBs应答者被保护

-HBeAg阳性母亲的新生儿

至少70%获得疫苗疗效以及阻止HBV传染

HBs基因变异选择，逃避抗HBs的可能性

少数婴儿发生应答

-非携带者母亲的婴儿

近100%被保护

强记忆性持久免疫力

*来自Hilleman，Vaccine 2001。

Figure 1. HBV Genome and Main Mutants

图1. HBV基因组和主要变异

Figure 2. The Virus Life Cycle and Its Inhibitors

图2. 病毒的生活史和它的抑制剂

Figure 3. Polymerase Domains and Main Antiviral Resistance Mutations

图3. 聚合酶区和主要抗病毒耐药变异

Figure 4. Emergence and Evolution of Antiviral Resistant Mutations

图4. 抗病毒耐药变异的出现和评估

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