Immunity to leishmaniasis is associated with a strong Th1-type immune response, as demonstrated by a positive delayed type hypersensitivity (DTH) reaction in the Leishmanin skin test (LST), along with lymphocyte proliferation and the production of high levels of IFN-γ and TNF-α [7] following stimulation with soluble leishmania antigen (SLA). This evidence concerns the gene IFNG and leishmaniasis.