HUMAN HERPESVIRUS-6 DNA IN PERIPHERAL-BLOOD CELLS AND SALIVA FROM IMMUNOCOMPETENT INDIVIDUALS

Human herpesvirus 6 (HHV-6) genome equivalents were quantitated in per ipheral blood mononuclear cells (PBMCs) and saliva from 20 healthy ind ividuals by the polymerase chain reaction (PCR). Nineteen of 20 subjec ts (95%) harbored HHV-6 DNA: 18 (90%) had HHV-6 in their PBMCs and 18 had HHV-6 in their saliva. Quantitative PCR revealed HHV-6 DNA levels ranging from negative to 4,000 HHV-6 genome equivalents per 106 PBMCs and from negative to 200,000 HHV-6 genome equivalents per ml of saliva . Longitudinal saliva samples from 15 HHV-6-seropositive subjects reve aled salivary HHV-6 DNA persistence in 13 subjects. HHV-6 antibodies w ere detected in 17 of 19 subjects, with titers ranging from 1:400 to 1 :51,200 (geometric mean titer, 1:2,500). Antibody titers did not corre late with HHV-6 DNA levels in PBMCs or saliva (P = 0.27 and P = 0.44, respectively). One subject with persistent HHV-6 DNA lacked detectable HHV-6 antibodies. The high prevalence of HHV-6 DNA in PBMCs and saliv a supports the concept that HHV-6 exists at these sites in normal indi viduals.