The long-term outcomes of patients transplanted due to acute liver failure with hepatic human herpesvirus-6 infection.

Human herpesvirus (HHV)-6, comprised of HHV-6A and HHV-6B, belongs to the betaherpesviruses that infect 95%-100% of humans. Primary infection, known as exanthema subitum, occurs in early childhood. Reactivations of latent HHV-6, mostly HHV-6B, are common after liver transplantation. The vast majority of them are asymptomatic; in a minority of cases, the virus may infect the liver transplant, causing graft dysfunction or hepatitis. An association between hepatic HHV-6 infection and indeterminate acute liver failure (ALF) has been shown, but the causality is not clear because of the ubiquitous nature of HHV-6. We have previously observed HHV-6B antigens in the explanted livers of most patients (80%, n = 32) transplanted with ALF of unknown cause, whereas it was not observed among those with ALF of known cause. After transplantation, half of the patients with pretransplant HHV-6 infection (9/18) developed recurrences. The aim of this study was to investigate their long-term course (9-14 years). Half of the patients with pretransplant HHV-6 developed recurrences. Two also showed cytomegalovirus (CMV) hepatitis, whereas none of the other patients demonstrated intrahepatic CMV. During the 9 years or more of follow-up, 1 graft and 2 patients were lost in both groups (HHV-6 recurrence/HHV-6-negative patients). The reasons for graft loss were hepatic arterial thrombosis and portal venous thrombosis. In addition 2 patients died in the HHV-6 recurrence group, one because of rethrombosis of hepatic artery (day 460) and one with a functioning transplant (4.5 years after transplantation). In the control group 1 patient died at 1.5 years and 1 at 10 years after liver transplantation because of pneumonia. HHV-6 relapse was common in ALF patients after transplantation. However, HHV-6 did not cause liver failure and had no significant long-term effect on survival.