CD4 and tuberculosis: Among subjects with active TB, the CD4+ T-cell count significantly correlated with the sum of ESAT-6 and CFP-10 peptide response (r2:0.47; p = 0.001) (Figure 3A), and with the sum of ESAT-6 and CFP-10 protein responses (r2:0.28; p = 0.02) (Figure 3B).