IFNG and tuberculosis: Studies with IFN-γ release assays (IGRAs) have shown that ESAT-6 and CFP-10-specific IFN-γ-secreting T cells often decline at the population level in TB patients during treatment, but this trend masks substantial inter-individual variation with some patients showing no decline and others an increase [3], [6], [31]-[34] making IGRAs unsuitable for monitoring treatment response or test of cure [3], [6], [35].