Figure 4: Differentiation between active and latent Mtb-infected subjects. (a) ROC curve (plotting sensitivity versus 1 − specificity) to discriminate active TB from LTBI patients. The area under curve (AUC) was 0.8444. (b) Analysis of triple-positive IFN-γ+ IL-2+ TNF-α+ CD4+ T cells, using a cut-off to score responses as either positive or negative. The subjects were considered as positive (black) whether the frequency of CD4+ T cells was >0.182% and negative (white) when the frequency was <0.182%. Horizontal bars represent the median values and horizontal dashed line indicates the cut-off of 0.182%.