Serum HHV8 DNA and Tat antibodies in Kaposi's sarcoma patients with and without HIV-1 infection.

Human herpesvirus 8 or Kaposi's sarcoma-associated herpesvirus (HHV8/KSHV) is believed to be the most important etiopathological factor of Kaposi's sarcoma (KS) and some specific types of malignant lymphomas. The diagnostic and prognostic significance of serum viral load in endemic (African) areas is poorly understood. In AIDS-related KS (AKS) it has been shown that HIV-Tat may be of pathogenic importance and that immunoreactivity to Tat may have prognostic significance. Here we report on the quantitative analysis of HHV8 DNA in serum from Tanzanian patients with KS (n = 19), either AIDS-related (AKS) (n = 14) or endemic KS (EKS) (n = 5) and non-KS control individuals (n = 4). Fourteen AKS sera were also tested for HIV-tat antibodies by a direct ELISA assay. In AKS patients detectable (12 out of 14) serum HHV8 DNA levels showed a median of 1400 copies/ml as compared to a median of 200 copies/ml for EKS, but for one AKS case with an exceptionally high level (25,500 copies/ml). The serum HHV8 DNA levels were usually higher in males (n = 17; median 580 DNA copies/ml) as compared to females (n = 6; median 120 DNA copies/ml) and in early, patch stages (n = 8; median 2,750 copies/ml) as compared to late, nodular stages (n = 11; median 200 DNA copies/ml). Of fourteen sera from AKS patients, seven were positive for antibody against HIV-1 tat. Epitope analysis of the anti-tat antibody spectrum showed reactivity to various non-functional sites, but not towards the functional epitopes 46-60 (TAR-binding region).