Other cytokines are shown to play a role in protection against TB; blocking TNF-α is reported to be associated with susceptibility to TB [25], IL-2, another Th1 cytokine, induces proliferation and maintenance of effector CD4+ and CD8+ T cells [26] and IL-17 has been associated with protection against TB in mice and humans [27], [28]. This evidence concerns the gene CD4 and tuberculosis.