IL6 and giardiasis: Interestingly, TNF-α deficiency does not affect the mechanisms involved in host defenses against Giardia infection, which includes the generation of IgA, the proliferation of mast cells, and the secretion of IL-6 or IL-4, suggesting that TNF-α does not exert its effects through these mechanisms mentioned previously in control of Giardia, but through other effector responses downstream of it (Zhou et al., 2007).