Relationship between interleukin-5 production and variations in eosinophil counts during HIV infection in West Africa: influence of Mycobacterium tuberculosis infection.

Eosinophils are important effectors of the non-specific immune response and we studied whether perturbations in the production of the type 2 cytokine, interleukin-5 (IL-5), could account for the variations in eosinophil counts observed in human immunodeficiency virus (HIV) infection. HIV-infected patients without helminthiasis were investigated in a cross-sectional study in West Africa. Eosinophil counts were significantly higher in CDC-B patients than in controls, but were dramatically decreased at the CDC-C stage. Phorbol 12-myristate 13-acetate (PMA)+ ionomycin-induced IL-5 production by peripheral blood mononuclear cells (PBMC) was decreased from the A stage of the disease, and significant correlations were observed between IL-5 production and eosinophil counts in tuberculosis (TB)-negative HIV-1-positive, TB-positive HIV-1-positive and TB-positive HIV-negative patient groups. Nevertheless, the production of IL-5 was not decreased in HIV-positive patients with TB, in contrast to HIV-positive patients without TB presenting with the same ranges of CD4+ counts. Our data suggest that, during HIV infection, the impairment in IL-5 production is one of the factors associated with the 'paradoxal' eosinopenia observed in tropical areas, but that IL-5 production during active TB is compensated by cellular subsets, yet to be identified.