CD4 and tuberculosis: The overall expression of HLA-DR + CD-38 and HLA-DR + Ki-67+ from double cytokine-producing PPD-specific CD4 + T cells among smear-negative and positive pulmonary TB patients was substantially higher compared with confirmed non-TB other respiratory illness, apparently healthy QFT positive and negative study participants (p-value = 0.00245, p-value = 0.0012, respectively) (data not shown).