It is well known that pro-inflammatory (e.g., IFN-γ, TNF-α, IL-1, IL-12) and anti-inflammatory (e.g., IL-4, IL-10, TGF-β) cytokines play different roles in resistance/susceptibility and the immunopathogenesis of leishmaniasis. The gene discussed is TGFB1; the disease is leishmaniasis.