Interleukin-17 (IL-17) is a pro-inflammatory cytokine that is mainly produced by CD4 + T cells. The role of Th17 during the human immunodeficiency virus (HIV)-1 infection is still unclear, but HIV-1 infection can cause a preferential depletion of Th17 cells. It has been shown that IL-15 elicits IL-17 production from human peripheral blood mononuclear cells. We studied the effect of IL-15 stimulation in vitro on IL-17 production from CD4 + mononuclear cells of HIV-infected patients. We observed that IL-15 triggers, in a dose-dependent manner, IL-17 secretion. This effect was blocked by anti-IL-15 monoclonal antibody (P = 0.01). Interestingly, IL-17 production was significantly lower in patients with detectable plasma viremia when compared with successfully treated HIV-infected patients (P = 0.02) and healthy controls, respectively (P