Prevalence of human herpesvirus 6 in Thai people and its correlation with human immunodeficiency virus type 1 infection.

Human herpesvirus 6 (HHV-6) is a human herpesvirus isolated from patients with various lymphoproliferative disorders and acquired immunodeficiency syndrome (AIDS). The prevalence of HHV-6 infection and its correlation as a cofactor in pathogenicity of HIV infection was investigated in serum samples from 365 healthy volunteers at various age groups, 50 persons at risk for HIV-1 infection, and 90 HIV-1 seropositive individuals. Sera were screened and titrated for antibodies against HHV-6 by a standard indirect immunofluorescence assay on an acetone fixed HHV-6 infected HSB2 cells. The data show high prevalence of HHV-6 in Thailand (71.7%) and the infection is acquired early in life. Prevalence of anti-HHV-6 IgG antibodies was not strikingly different among people at risk for HIV infection, asymptomatic HIV-1 infected cases, and aged-matched controls with low risk for HIV-1 infection. The AIDS cases showed high titers of anti-HHV-6 IgG antibody and high rates for presence of anti-HHV-6 IgM antibody (33.3%) which suggests higher prevalence of HHV-6 infection by either reactivation of an earlier HHV-6 infection or a new primary infection.