IFNG and tuberculosis: Moreover, the overall level of CD-38 + Ki-67 + expressing PPD specific IFN-γ + TNF-α + CD4 + T cells from smear-positive pulmonary TB patients was much higher compared with smear-negative pulmonary TB patients (p value= < 0.0001), confirmed non-TB respiratory patients (p-value = < 0.0001), apparently healthy QFT positive and negative study participants (p value= < 0.0001, p value= < 0.0001, respectively).