IFNG and tuberculosis: IFN-γ is a key cytokine in activation of macrophages for mycobacterial stasis and killing [2]; the persistence of low IFN-γ production from the middle to end of therapy in patients with IFNG +874 AA genotype and INFG +2109 AG genotype could result in a worse prognosis to the resolution of the active disease and efficiency of the anti-TB treatment and may also underlie their increased risk for reactivation of a latent PTB focus.