Assessment and management for latent tuberculosis before advanced therapies for immune-mediated inflammatory diseases: A comprehensive review

Tuberculosis (TB), caused by Mycobacterium tuberculosis , is the most significant infectious cause of mortality across the globe. While TB disease can prey on immunocompetent individuals, it is more likely to occur in immunocompromised individuals. Immune-mediated inflammatory diseases (IMIDs) are a group of diseases (rheumatoid arthritis, inflammatory bowel disease, ankylosing spondylitis, psoriasis, hidradenitis suppurativa, autoimmune blistering diseases, and others) where there may be a need for systemic immunosuppression to control the disease manifestations, treat symptoms and improve long term outcomes. Immunosuppression may predispose them to active TB either from recent infection or reactivation of Latent TB (LTB). The major determinants of reactivation include the type of therapy (highest risk with TNF inhibitors and JAK inhibitors) and the underlying TB endemicity. The strategy to avoid TB reactivation includes the detection of LTB using tests that detect immunoreactivity to TB antigens (interferon-gamma release assays or tuberculin skin test) and treating LTB before or with initiation of IMID therapies. Available diagnostic tests have deficiencies in diagnostic sensitivity to detect LTB and even worse capability in predicting reactivation of TB. In addition to immunological tests, more stringent testing strategy utilizing one or many LTB equivalents may point towards subclinical TB. LTB equivalents include clinical (past history of TB, recent exposure to TB) and radiological criteria (use of chest roentgenogram, computed tomography, or, sometimes positron emission tomography - computed tomography). The present review summarizes the risk factors for TB reactivation in patients initiated on advanced therapies, geographically appropriate strategies for LTB testing, and treatment of LTB.