Dynamic Changes in IFN-gamma Plasma Levels Following Anti-TNF Treatment in Patients With Inflammatory Rheumatic Diseases Undergoing Serial QuantiFERON-TB Gold In-Tube Testing: a Prospective Study in a Low Tuberculosis Burden Country

The screening for latent tuberculosis infection (LTBI) prior to the onset of anti-tumor necrosis factor therapy, as well as a watchful monitoring during the treatment, is strongly recommended. Tuberculin skin test (TST), universally used for this purpose, lacks sensitivity and specificity. The novel screening tools, including QuantiFERON-TB Gold In-Tube (QFT-GIT), have shown a higher specificity compared to TST, but their feasibility in the setting of immunosuppression remains unclear. Aims of this study were to investigate the performance of QFT-GIT and its agreement with TST in patients awaiting anti-tumor necrosis factor (TNF) therapy, and to evaluate the usefulness of serial QFT-GIT during the treatment with biologics to assess whether dynamic changes in interferon (IFN)-gamma levels may be helpful in identifying reactivation of LTBI or cases of newly acquired tuberculosis.