The level of IFN-γ⁺ and TNF-α⁺ responses from PPD specific CD4+ T cells during the standard anti-TB treatment follow up time period.

A:—The level of IFN-γ+ and TNF-α+ responses among smear negative PTB patients. B:—The level of IFN-γ+ and TNF-α+ among smear positive PTB patients. Cytokine evaluation was performed after overnight stimulation with PPD or control cultures. The bars within each plot indicate the median value for each marker and time point. Data analysis was done using non-parametric Wilcoxon matched-paired rank test with significant p values indicated. Stimulation indices (SI) represent the ratio of frequencies in the presence of PPD to that of the absence of PPD. Baseline represents values prior to initiation of standard anti-TB drugs. 2nd and 6th month refers to time after therapy initiation.