Background: Betaherpesviruses human herpesvirus-6 and -7 (HHV-6, HHV-7), which are closely related to cytomegalovirus (CMV), have been reported in transplant patients. In this retrospective study, we investigated the occurrence of HHV-6 and HHV-7 antigenemia in relation to symptomatic CMV infection after liver transplantation.
Methods: Sample material from 64 adult liver transplant recipients was included in the study. The patients were monitored weekly for CMV, HHV-6, and HHV-7. CMV infections were diagnosed by pp65-antigenemia and viral cultures. Concomitantly HHV-6 and HHV-7 antigens were demonstrated in peripheral blood mononuclear cells by monoclonal antibodies against both variants A and B and immunoperoxidase staining. Altogether 540 post-transplant blood specimens were analyzed.
Results: Nineteen patients (30%) developed symptomatic CMV pp65 antigenemia during the first 3 months (mean 33 days, range 5-62 days) post-transplantation and were treated with intravenous ganciclovir. Concurrent HHV-6 antigenemia was detected in 16/19 (median 9 days, range 6-24 days) and HHV-7 antigenemia 15/19 patients (median 17 days, range 5-58 days) after transplantation. HHV-6 appeared before CMV in most cases (12/16), HHV-7 usually together with CMV. In those cases that HHV-6 preceded CMV antigenemia, it also was a possible cause of graft dysfunction. HHV-7 and CMV were so closely overlapping, that no symptoms could solely be linked with HHV-7.
Conclusion: HHV-6 and HHV-7 antigenemia usually occurred together with symptomatic CMV infection after liver transplantation. HHV-6 preceded CMV, but HHV-7 appeared together with CMV. Further investigation of the clinical significance of HHV-6 and HHV-7 antigenemia in organ transplant patients is necessary.