CD4 and ancylostomiasis: In the present study, we have demonstrated by functional assays that both T CD4+ and CD8+ cell proliferative responses to either ES or hookworm crude antigen were increased after Treg depletion, followed by an increase of IL-2 secretion and lower levels of IL-10, although not statistically significant, further implying that these cells may exert a specific immunomodulatory effect during persistent hookworm infection.