Anti-tumor necrosis factor (TNF) therapy for active ulcerative colitis (UC) and Crohn's disease (CD) is associated with increased risks of tuberculosis (TB) infection. We analyzed the incidence and clinical features of Korean patients with inflammatory bowel disease (IBD) who developed active TB during anti-TNF therapy.

Ten cases of active TB developed in patients treated with infliximab (n=592) or adalimumab (n=229) for UC (n=160) or CD (n=661) were reviewed. We analyzed demographics, interval between start of anti-TNF therapy and active TB development, tests for latent TB infection (LTBI), concomitant medications, and the details of diagnosis and treatments for TB.

The incidence of active TB was 1.2% (10/821): 1.5% (9/592) and 0.4% (1/229) in patients receiving infliximab and adalimumab, respectively. The median time to the development of active TB after initiation of anti-TNF therapy was three months (range: 2–36). Three patients had past histories of treatment for TB. Positive findings in a TB skin test (TST) and/or interferon gamma releasing assay (IGRA) were observed in three patients, and two of them received anti-TB prophylaxis. Two patients were negative by both TST and IGRA. The most common site of active TB was the lungs, and the active TB was cured in all patients.

Active TB can develop during anti-TNF therapy in IBD patients without LTBI, and even in those with histories of TB treatment or LTBI prophylaxis. Physicians should be aware of the potential for TB development during anti-TNF therapy, especially in countries with a high prevalence of TB.