IFNG and tuberculosis: The fact that the IFN-γ level in the positive-control well increased significantly after treatment with TNF-α antagonists, probably because of an improvement in the immunocompromised state of these patients, whereas the IFN-γ level in the tuberculosis-antigen well did not change, also supports the notion that results of the QTF test are not affected by treatment with TNF-α antagonists.