IFN-γ, the hallmark Th1 cytokine, is central in protection against tuberculosis by activation of macrophages to generate microbicidal effectors and pro-inflammatory cytokines, such as tumor necrosis factor alpha (TNF-α) which contributes to macrophage activation, granuloma formation and control of mycobacterial infection [3], [4]. This evidence concerns the gene IFNG and tuberculosis.