In visceral Leishmaniasis, the host ability of parasite resistance is characterized by generation of Th1 response, which produce pro-inflammatory cytokines such as IL-2, IL-12, etc. whereas generation of Th2 response, characterized by IL-4 and TGF-β secretion, favors for survival of the parasite inside the host (Singh et al., 2012; Rodrigues et al., 2014). The gene discussed is IL4; the disease is visceral leishmaniasis.