IFNG and tuberculosis: The tuberculin skin test (TST) and MTB specific interferon-gamma (IFN-γ) release assays (IGRAs), such as QuantiFERON-TB Gold In-Tube (QFT-G-IT) assay (Cellestis/Qiagen, Carnegie, Australia) and T-SPOT TB assay (Oxford Immunotec, Abingdon, UK) are still the main tools used for the diagnosis of TB infection.