Using immunosuppression in the setting of KT could disrupt the protection against TB and increase the risk of reactivation through multiple mechanisms, such as: depletion of all types of T cells, decrease in activation and proliferation of T cells, decrease in IL-2 synthesis, decrease in the production of Th-1 type cytokines or impairment of cellular immunity almost completely [9,24,32,43,80]. The gene discussed is IL2; the disease is tuberculosis.