The regulatory T (Treg) cells subgroup also plays an important role in the process, as it maintains the cell-mediated immunity effector cells in homeostasis.20, 21, 22 The most important component of the defense against TB through the Th1 pathway is the production of the cytokine IFN-γ, which activates macrophages and stimulates phagocytosis, phagosome maturation, production of reactive nitrogen intermediates and antigen presentation. The gene discussed is IFNG; the disease is tuberculosis.