Interleukin-17 producing T helper cells are increased during natural Plasmodium vivax infection.

Recent evidences have demonstrated the importance of Th17 cells in host defense against infectious diseases. However, little is known about their role in parasitic infections. Here, we showed that uncomplicated acute vivax malaria induce a significant expansion of IL-17-producing CD4(+) T cells associated to a pro-inflammatory cytokine profile. Furthermore, we demonstrated a correlation between numbers of IL-17(+)CD4(+) T cells and circulating CD4(+) T-cells producing IFN-γ, IL-10 and TGF-β. Finally, correlations between number of these cells and morbidity or parasitemia were not detected. Further studies are underway to investigate whether IL-17-producing CD4(+) T cells are critically involved in the immunity against Plasmodium vivax infection.