Protein levels of interleukin-12 p70 holomer, its p40 chain and interferon-gamma during advancing HIV infection

Background: a switch from T helper 1 (TH1) to T helper 2 (TH2)-like cytokine production has been proposed for progressive HIV infection. Objective: to study whether this hypothesis is reflected bq altered IL-12 and IFN-gamma serum levels in HIV patients. Methods: rye measured serum levels of IL-12 pill and p70 and IFN-gamma in 90 HIV seropositive patients at differing disease stages and in 10 healthy controls by radioimmunoassays. These cytokines were compared to established surrogate markers of immunodeficiency. Results: IFN-gamma, as well as IL-12 p-EO and p70, levels were significantly increased in HIV patients compared to controls, However, IFN-gamma and IL-12 shotted no significant variations with progressive stages of immunodeficiency. IFN-gamma levels showed a significant positive correlation to the progression marker beta(2)-microglobulin and correlated negatively with CD4(+) lymphocyte counts, In addition, IFN-gamma concentrations were related to sTNF-R p55 and p75 serum levels. Interestingly, IFN-gamma was related to IL-12 only with respect to p-40, but not to p70 Conclusions: although our data do not necessarily reflect cytokine secretion at the single cell level or the cytokine milieu in the lymphoid microenvironment, our results from peripheral blood fail to demonstrate progressively decreased IL-12 and IFN-gamma serum levels in HIV infected patients.