IFNG and tuberculosis: Although antigen-specific IL-2- IFN-γ+ secreting T-cells are elevated in active tuberculosis in comparison to past tuberculosis and LTBI and can be easily identified by FluoroSpot, the parallel diagnosis of IL-2 and IFN-γ secretion by antigen-specific T-cells does not allow a reliable differentiation between different states of M. tuberculosis infection in clinical practice.