CD4 and tuberculosis: When cryopreserved PBMC were analyzed by flow cytometry, we saw a significant increase in the proportion of CD4+ T cells simultaneously producing IFN-γ and IL17 (p = 0.0081) and CD8+ T cells producing IFN-γ alone (p = 0.0162) following overnight stimulation with PMA/Ionomycin in TB/Flu compared to TB only patients (Figures 3A,B).