Serum IL-10 levels in HIV-positive subjects: correlation with CDC stages

HIV-1 infection and the HIV gp120 have been shown to induce an IL-10 increase in cultured peripheral blood mononuclear cells. Furthermore, the expression of this cytokine has been reported to increase in lymphnodes of infected patients along the disease course, and a shift from the TH-1 towards the TH-0/TH-2 phenotypes (with subsequent IL-10 release) has been hypothesized to underly AIDS progression. In this study the serum IL-10 levels found in 30 HIV-negative controls and in 65 HIV-positive patients, untreated with AZT and negative for HBsAg and HCV-Ab have been compared, using a commercial, competitive ELISA method based on a polyclonal anti-IL-10 serum. With this test, HIV-positive sea showed IL-10 levels significantly higher than those found in the controls. In addition the IL-10 levels progressively increased in the subsequent CDC stages, without further changes from the stage III to the stage IV. Accordingly, patients evaluated two times in CDC stage II, with a time interval of at least one year, showed significant IL-10 increases, even more pronounced when the same patients passed from CDC stage II to stage III. Furthermore, a significant, negative correlation was observed between the circulating IL-10 levels and the patients' CD4/CD8 ratios. These data may be important from a clinical point of view since IL-10 monitoring could be considered as a surrogate marker for evaluating the disease progression. In addition, several immunological abnormalities present in HIV positive patients, such as the monocyte/macrophage impairment and the hypergammaglobulinemia could be related to the enhanced IL-10 expression.