CMV infection is usually associated with concurrent HHV-6 and HHV-7 antigenemia in liver transplant patients.

Human herpesvirus 6 and 7 (HHV-6, HHV-7) have been recently reported in liver transplant patients. HHV-6 may cause fever, neurological disorders and hepatitis. The clinical significance of HHV-7 is less clear. HHV-6 and -7 are closely related to cytomegalovirus (CMV), and interactions between the viruses have also been suggested. In this study, we investigated the post transplant HHV-6 and -7 antigenemia was in relation to symptomatic CMV disease after liver transplantation. Consecutive 34 adult liver allograft recipients transplanted during 1999-2000 were included in the study. CMV infections were diagnosed by the frequent monitoring of pp65-antigenemia and by viral cultures. HHV-6 and -7 were demonstrated, by using immunoperoxidase staining and monoclonal antibodies against the virus specific antigens, in the mononuclear cells from the same blood specimens which were obtained for CMV pp65 monitoring. Altogether 322 blood specimens were analyzed. CMV disease was diagnosed in 12 (35%) patients during the first 3 months (first pp65 positive specimen mean 25 days, range 8-61 days) after transplantation. Concurrent HHV-6 antigenemia was detected in 10/12 (mean 14 days, range 6-22 days) and HHV-7 antigenemia in 9/12 patients (mean 25 days, range 10-89 days) after transplantation. HHV-6 usually appeared slightly before CMV. All CMV infections were successfully treated with ganciclovir and the CMV-antigenemia subsided. HHV-6 and -7 antigenemia also responded to the antiviral treatment, but more slowly than CMV. In conclusion, CMV infection was usually associated with HHV-6 and -7 antigenemia in liver transplant patients. The results support the suggestion that CMV, HHV-6 and -7 may have interactions. The clinical symptoms of CMV infection, may also be linked with HHV-6 or -7.