HUMAN HERPES VIRUS-6 INFECTIONS IN HOSPITALIZED RENAL-TRANSPLANT RECIPIENTS

Herpesviruses are a major cause of morbidity and mortality in renal transplant recipients. Recently, a new member of the herpesvirus family, human herpesvirus 6 (HHV-6), has been identified. We investigated the incidence and clinical manifestations of HHV-6 infections in 25 hospitalized renal transplant recipients. HHV-6 infections were documented serologically by comparing pre- and post-transplantation antibody titers using an indirect immunofluorescence assay. Infections caused by cytomegalovirus, Epstein-Barr virus, herpes simplex virus and varicella-zoster virus were also studied. During the mean follow-up period of 3 1/2 months post-transplant (range, 2 to 6 months), 9 recipients (36%) had serologic evidence of HHV-6 infection. Two patients seroconverted, suggesting primary HHV-6 infection. These patients had febrile illnesses, skin rash and malaise. Seven recipients had a non-primary HHV-6 infection (reactivation/reinfection) documented by a > 4-fold rise in antibody titer that was associated with clinical illness in 5 of 7 patients. Two recipients developed primary cytomegalovirus infection and both had evidence of non-primary HHV-6 infection. Seven of 9 recipients (77%) who developed HHV-6 infection had received acyclovir prophylaxis. We conclude that primary and non-primary HHV-6 infections occur in renal transplant recipients and can be associated with fever, skin rash and malaise. HHV-6 infections can occur despite high-dose oral acyclovir prophylaxis.