IFNG and tuberculosis: Measurement of host immune responses, like the tuberculin skin test (TST) that is the intracutaneous injection of purified protein derivative (PPD) into the forearm, and interferon-gamma (IFN-γ) release assays (IGRAs) including the QuantiFERON®-TB Gold In-Tube (QFT) assay and T-SPOT.TB test, remains the common diagnosis for TB infection [6].