Protective immunity to cutaneous leishmaniasis requires a robust IL12 driven type 1 helper T-cell (Th1) mediated response that produces high levels of interferon-gamma (IFNG), which ultimately promotes anti-microbicidal production of nitric oxide (NO) and reactive oxygen species (ROS) that destroy invading pathogens [16,17]. This evidence concerns the gene IFNG and cutaneous leishmaniasis.