Human herpesvirus-6 infection in liver transplant recipients : documentation of pathogenicity

The new herpesvirus, human herpesvirus-6 (HHV-6), is able to cause clinical illness after transplantation; however, the pathogenic potential and the clinical features of HHV-6 have not been defined in liver transplant recipients. We report the first cases of invasive and symptomatic infection due to HHV-6 in liver transplant recipients. HHV-6 infection occurred in four liver transplant recipients at a median of 50 days after transplant (range 17-90 days). Severe cytopenia was observed in all patients; leukopenia (with median leukocyte count of 1400/mm3) was the most commonly effected bone marrow lineage. One of the four patients had interstitial pneumonitis due to HHV-6. No other virus (e.g., cytomegalovirus) or another pathogen was detected in the lungs, blood, or bone marrow in any of the above patients. Our data suggest that HHV-6 can be a pathogen in liver transplant recipients; idiopathic bone marrow suppression is its predominant clinical sequelae. Recognition of HHV-6 infection is clinically pertinent because HHV-6 is potentially treatable with the currently available antiviral agents.