Relationship of human herpesvirus 8 peripheral blood virus load and kaposi's sarcoma clinical stage

To determine the relationship between human herpesvirus 8 (HHV-8 or Kaposi's sarcoma-associated herpesvirus) peripheral blood virus load and Kaposi's sarcoma (KS) clinical stage. Blinded, cross-sectional analysis of peripheral blood HHV-8 DNA levels in persons with AIDS-related KS in Harare, Zimbabwe. Subjects were stratified by KS clinical stage. The amount of HHV-8 DNA in plasma and peripheral blood mononuclear cells (PBMC) was determined by quantitative real-time PCR amplification of the HHV-8 open reading frame 26. Thirty-one HIV-1/HHV-8-coinfected persons were studied: 26 subjects had histologically confirmed KS (one stage II, 11 stage III and 14 stage IV) and five subjects had antibodies to HHV-8 but did not have KS. The age, CD4 lymphocyte count and plasma HIV-1 RNA levels were similar in all groups. HHV-8 DNA was detected in the plasma of all HHV-8-infected subjects (range < 2.4 to 5.2 log10 copies/ml), but plasma HHV-8 DNA levels were not associated with KS disease stage. In contrast, the amount of HHV-8 DNA in PBMC (range < 0.7 to 4.5 log10 copies/microg) was strongly associated with KS clinical stage (P = 0.005). Among stage IV KS cases, there was a linear relationship between plasma and PBMC HHV-8 DNA levels (r2 = 0.42; P = 0.01). The strong association observed between the extent of KS disease and the levels of HHV-8 DNA in PBMC provides further evidence for a relationship between HHV-8 virus load and KS pathogenesis.