Brief report: primary human herpesvirus 6 infection in a patient following liver transplantation from a seropositive donor.

A virus, isolated from peripheral blood lymphocytes of a patient 23 days after liver transplantation, was identified by negative contrast and thin-section electron microscopy, DNA hybridisation, and immunofluorescence as human herpesvirus 6 (HHV-6). The patient was seronegative for antibodies to HHV-6 before receiving the liver from a seropositive donor. Seroconversion for IgM and IgG antibodies occurred at the same time as the viraemia, indicating a primary response to HHV-6 infection that was probably acquired from the donor liver. The relationship of the infection to the patient's subsequent disease episodes is discussed.