Evidence for horizontal and not vertical transmission of human herpesvirus8 in children born to human immunodeficiency virus-infected mothers

A survey of antibody responses to human herpesvirus 8 (HHV-8) was undertake n to examine the mode of transmission of this virus to children born to mot hers with HIV. Methods. Serum samples from a cohort of 92 mother-infant pairs and a cross- sectional cohort of 100 children (median age, 4 years) were tested. In the cohort of mother-infant pairs, 14 infants were HIV-infected, 72 were not an d the HIV status was unknown for 6. In the cohort of children 70 were HIV i nfected and 30 were vertically exposed but uninfected. Serologic responses to two HHV-8 antigens, latency associated nuclear antigen and the structura l antigen encoded by open reading frame 65 were detected by immunofluoresce nt antibody test and enzyme-linked immunoassay. Results were confirmed by W estern blot. Results. All HHV-8-seropositive mothers were African (17 of 92, 18.5%). Six of their infants were HHV-8-seronegative and 11 had at least 1 HHV-8-serop ositive sample. One of the 11 infants tested only at birth had a lower anti body titer than the mother; the remaining 10 infants had decreasing titers up to 7 months of age and 6 became seronegative. No infants born to HHV-8-s eronegative mothers had antibodies to the virus. The seroprevalence to HHV- 8 was 6% in the cohort of children. All had African mothers and their media n age was greater than that of the cohort (8.4 vs. 4.0 years). Five were co infected with HIV. Conclusions. HHV-8 was not vertically transmitted by any of the HIV-coinfec ted mothers. Acquisition of antibody to HHV-8 occurred in older children, i mplying a horizontal route of transmission.