Human herpesvirus 6 infections after bone marrow transplantation: Clinicaland virologic manifestations

Human herpesvirus 6 (HHV-6) DNA levels in peripheral blood mononuclear cell s were prospectively evaluated in 20 cytomegalovirus-seronegative allogenei c marrow transplant patients and in 10 healthy control subjects. Blood and saliva specimens obtained weekly for 3 months after transplant were evaluat ed by quantitative HHV-6 polymerase chain reaction. One of 20 patients expe rienced primary HHV-6 infection after marrow transplant (seroconversion, HH V-6 viremia, skin rash); 18 of 20 had increased peripheral blood mononuclea r cell HHV-6 DNA levels consistent with asymptomatic reactivations, and 1 p atient experienced a reactivation-associated skin rash. Genotyping revealed HHV-6 variant B DNA in all cases. Therapy with acyclovir or intravenous im munoglobulin was not correlated with lower HHV6 DNA levels. Thus, asymptoma tic HHV-6 reactivations appear to be common following allogeneic marrow tra nsplantation. Among HHV-6-seronegative and viral DNA-negative patients, pri mary HHV-6 infection can ensue in association with self-limited clinical sy mptoms, including diffuse maculopapular rash.