KSHV ANTIBODIES AMONG AMERICANS, ITALIANS AND UGANDANS WITH AND WITHOUT KAPOSIS-SARCOMA

A major controversy regarding Kaposi's sarcoma-associated herpesvirus (KSHV or HHV8)(1,2) is whether or not it is a ubiquitous infection of humans(3,4). Immunoassays based on KSHV- and Epstein-Barr virus (EBV)- coinfected cell lines show that most US AIDS-KS patients have specific antibodies to KSHV-related antigens(2,5,6). We have developed a sensi tive indirect immunofluorescence assay (IFA) based on an EBV-negative, KSHV-infected cell line, BCP-1. When we used this IFA assay, KSHV-rel ated antibodies were found in 71-88% of serum samples from US, Italian and Ugandan AIDS-KS patients, as well as all serum samples examined f rom HIV-seronegative KS patients. Although none of the US blood donors examined were KSHV seropositive by IFA, intermediate and high seropre valence rates were found in Italian and Ugandan control populations. A ntibody kinetics showed that more than half of the AIDS-KS patients wh o were examined IgG-seroconverted before KS development, and antibody levels did not decline after seroconversion. For these patients, serop ositivity rates increased linearly with time, suggesting that the rate of infection was constant and that the risk of developing KS once inf ected with KSHV is not highly dependent on the duration of infection. These data strongly suggest that KSHV is not ubiquitous in most popula tions and that the virus may be under strict immunologic control in he althy KSHV-infected persons.