IFNG and tuberculosis: Currently available novel LTBI diagnostics are based on interferon-γ release assays (IGRAs), which measure IFN-γ released by T-cells (QFT-Gold) or IFN-γ-secreting T-cells (T-SPOT.TB) that are stimulated with Mtb-specific antigens (ESAT-6, CFP-10, and TB 7.7) (7).