A serological investigation of human herpesvirus 6 infections in liver transplant recipients and the detection of cross‐reacting antibodies to cytomegalovirus

Sera from 50 orthotopic liver transplant recipients were examined for antibodies to human herpesvirus 6 (HHV-6) and cytomegalovirus (CMV), and the findings correlated with the clinical condition of the patients. Both primary and secondary HHV-6 infections were detected serologically following liver transplantation. Interpretation of serological assays is complicated by CMV and HHV-6 antibody cross reactions which were common. Sera from 5 patients became HHV-6 antibody negative following absorption with CMV infected cells. Thirty patients were initially seronegative for HHV-6 antibodies, 12 remained so following transplantation, 5 developed cross reacting antibodies, and 13 seroconverted. The seroconversions occurred at 4 to 8 weeks post-transplant in the same time period as CMV antibody rises. HHV-6 IgM was detected in only 4 of the 13. Of the 7 patients who had serological evidence of active HHV-6 infections but no evidence of CMV infection, 4 (56%) had fever, 1 (14%) hepatitis, 1 (14%) lung dysfunction, and 3 (42%) neurological disorders. In the 12 patients who remained HHV-6 antibody negative, there were fewer fevers and neurological disorders.