IL4 and colitis: A remarkable example of how HDPs modulate the host immune response is observing the outcome of the inoculation of hookworms-derived antigens, which are a complex mixture of over 100 proteins with unknown functions in colitis-induced mouse models resulted in the induction of great levels of T-helper type 2 (Th2-related) cells and regulatory cytokines, including IL-10, IL-4, and TGF-β and a corresponding decrease in the inflammatory cytokines including IL-13, TNF-β, IL-1, IFN-γ, and IL-17a [39–42].