Proper T-cell activation is a prerequisite for effective cell mediated immune (CMI) response against intracellular pathogens like mycobateria, leishmania, etc. Advanced stages of mycobacterial infections like tuberculosis and leprosy show loss of T-cell functions, including reduced IL-2 production, which could be due to improper T-cell activation[17]. The gene discussed is IL2; the disease is tuberculosis.