Acute Hepatitis With Periportal Confluent Necrosis Associated With Human Herpesvirus 6 Infection in Liver Transplant Patients

Objectives: To correlate human herpesvirus 6 (HHV-6) viral load with pathologic features in graft acute hepatitis of unknown origin. Methods: Liver frozen samples from 26 patients with graft hepatitis of unknown origin were available for HHV-6 DNA quantification. Results: In 10 (38.5%) of 26 liver samples, HHV-6 DNA was detectable, with a median viral load of 3.84 log 10 copies/10 6 cells. Confluent periportal necrosis was observed in 4 of 10 patients and associated with high viral load. These 4 patients responded to antiviral therapy. Mild unspecific hepatitis was observed in 4 patients with low intragraft viral load and in 2 patients with high viral load in a context of deep immunosuppression. Patients with HHV-6–negative graft hepatitis disclosed lobular necrotico-inflammatory activity without periportal necrosis. Conclusions: Our study provides data supporting the pathogenic role of HHV-6 for liver allografts. The presence of confluent periportal necrosis could be a clue for prompt diagnosis of HHV-6–induced graft hepatitis.