Retesting for latent tuberculosis in patients with inflammatory bowel disease treated with TNF-α inhibitors.Papay P, Primas C, Eser A, Novacek G, Winkler S, Frantal S, Angelberger S, Mikulits A, Dejaco C, Kazemi-Shirazi L, Vogelsang H, Reinisch W. Aliment Pharmacol Ther. 2012 Sep 15. BACKGROUND: Patients treated with TNF-α inhibitors (TNFi) are at high risk of reactivation of latent tuberculosis (LTB). Prospective studies on monitoring of TB reactivation and/or infection in this risk group are lacking. AIM: To test the conversion and reversion rate of screening tests for latent TB serial tuberculin skin test (TST) and interferon-γ release assay (IGRA) under ongoing TNFi therapy. METHODS: We retested consecutive patients with IBD receiving TNFi therapy for a minimum of 5 months for LTB using IGRA and TST. A detailed patient history and concomitant therapy were recorded for each subject. RESULTS: After a median of 34.9 weeks (20.7-177.7), IGRA was retested in 184/227 patients (81.1%; Crohn’s disease n = 139, ulcerative colitis n = 45) still under index TNFi. TST was available in 144/184 subjects (78.2%). The majority of patients were TNFi naïve (147/184, 79.9%). A subgroup of patients who received isoniazid due to diagnosis of latent TB at baseline reverted to negative at retesting [n = 32; 6/13 patients (46.2%) baseline positive IGRA and 3/22 patients (13.6%) baseline positive TST]. In patients without diagnosis of LTB at baseline no permanent IGRA conversion was observed, but there were 6/144 (4.2%) TST conversions from negative to positive. No single case of TB reactivation or infection was recorded during the observation period. CONCLUSIONS: During treatment TNF-α inhibitors conversion was observed for tuberculin skin test, but not interferon-γ release assay. As compared with tuberculin skin test, interferon-γ release assay reverted in nearly half of isoniazid-treated patients for latent tuberculosis. However, the fact that patients in whom the interferon-γ release assay test result remained positive did not develop active tuberculosis during follow-up questions the utility of interferon-γ release assay as a monitoring tool during chemoprevention.