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 3½ 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.