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

► Circulating Th17 cell number was evaluated during acute vivax malaria infection. ► Correlation between Th17 cell number and cytokine production was assessed. ► We showed the expansion of Th17 cells during natural malaria vivax infection. ► Th17 cell number was correlated with regulatory cytokine profile. ► Correlation between Th17 cell number and morbidity or parasitemia were not detected.