Negative predictive value of TST and IGRA in anti-TNF treated patients

Abstract

To the Editors: Anti-tumour necrosis factor (TNF) therapy is increasingly used in chronic inflammatory diseases. These agents are related to an increased risk of tuberculosis (TB) depending on the clinical setting and the anti-TNF agent used, so screening is mandatory before its start [1]. Inhibition of TNF-α and TNF-regulated chemokine networks is the presumed biological basis [2]. Though patients with chronic inflammatory diseases and suspected latent TB infection (LTBI) who are candidates for anti-TNF therapy are at higher risk of TB reactivation, they are prone to false-negative tuberculin skin test (TST) and interferon-γ release assay (IGRA) results due to T-cell hyporesponsiveness, either because of illness or immunosuppressive medications [3]. The reliability of these tests in this population is therefore of interest, but currently unclear. The negative predictive value (NPV) of TST and IGRA is still not defined in this group of patients. National guidelines for diagnosis and treatment of LTBI require screening of any candidate on anti-TNF therapy, prior to starting it, through assessment of …