IFNG and tuberculosis: Among interferon-gamma release assays (IGRAs), the Quanti-FERON-TB Gold Plus (QFT-Plus; Qiagen, Hilden, Germany) test is based on the levels of interferon-gamma (IFN-γ) released by a CD4+ and CD8+ T-cell-mediated immune response after in vitro stimulation of human whole-blood by antigens specific to the Mycobacterium tuberculosis complex.