Effect of primer selection on estimates of GB virus C (GBV-C) prevalence and response to antiretroviral therapy for optimal testing for GBV-C viremia

J Clin Microbiol. 2006 Sep;44(9):3105-13. doi: 10.1128/JCM.02663-05.

Abstract

GB virus C (GBV-C; also called hepatitis G virus) is a common cause of infection associated with prolonged survival among HIV-infected individuals. The prevalences of GBV-C viremia vary widely in different studies, and there has been poor agreement among different laboratories performing GBV-C RNA detection in quality control studies. To determine the optimal method of measuring GBV-C RNA in clinical samples, samples obtained from 939 HIV-infected subjects were studied using reverse transcription (RT)-PCR methods amplifying four separate regions of the GBV-C genome. Primers amplifying the E2 coding region were 100% specific; however, their sensitivity was only 76.6%. In contrast, primers amplifying three additional conserved regions of the GBV-C genome (the 5' nontranslated region and the nonstructural protein-coding regions 3 and 5A) were more sensitive but produced higher rates of false-positive results. Using low-specificity primer sets influenced the significance of association between GBV-C viremia and response to antiretroviral therapy. Using a quantitative GBV-C RNA method, the GBV-C RNA concentration did not correlate with baseline or set point HIV RNA levels; however, a correlation between negative, low, and high GBV-C RNA levels and increasing reduction in HIV RNA following antiretroviral therapy was observed. Subjects with both GBV-C E2 antibody and viremia had significantly lower GBV-C RNA levels than did viremic subjects without E2 antibody. These studies demonstrate that accurate detection of GBV-C RNA by nested RT-PCR requires the use of primers representing multiple genome regions. Analyses based on testing with single primers do not lead to reliable conclusions about the association between GBV-C infection and clinical outcomes.

Publication types

  • Randomized Controlled Trial
  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Anti-HIV Agents / therapeutic use
  • Antibodies, Viral / blood
  • DNA Primers*
  • Drug Therapy, Combination
  • Female
  • Flaviviridae Infections / drug therapy*
  • Flaviviridae Infections / epidemiology*
  • Flaviviridae Infections / virology
  • GB virus C / genetics
  • GB virus C / isolation & purification*
  • HIV Infections / complications
  • HIV Infections / drug therapy
  • Humans
  • Prevalence
  • RNA, Viral / analysis
  • RNA, Viral / isolation & purification
  • Reverse Transcriptase Inhibitors / therapeutic use
  • Sensitivity and Specificity
  • Treatment Outcome
  • Viral Envelope Proteins / genetics
  • Viral Envelope Proteins / immunology
  • Viremia / drug therapy*
  • Viremia / epidemiology*
  • Viremia / virology

Substances

  • Anti-HIV Agents
  • Antibodies, Viral
  • DNA Primers
  • RNA, Viral
  • Reverse Transcriptase Inhibitors
  • Viral Envelope Proteins
  • glycoprotein E2, GB virus C