P425 Rates of tuberculosis infection in Crohn’s Disease patients before and during anti-tumor necrosis factor therapy

GeorgievaPhD, A.C.(1);Atanassova, A.(1);Mirchev, M.(1);

(1)Medical university- Varna- Bulgaria, University Hospital St. Marina- Clinic of Gastroenterology, Varna, Bulgaria;


In the last 20 years, IBD treatment has made great progress with the implementation of biological drugs. Although the use of anti-tumor necrosis factor-alpha (anti-TNF-α) agents is highly effective in achieving and maintaining remission 1, anti-TNF-α agents are associated with a 5-fold increased risk of reactivation of various opportunistic infections, including TBI 2,3.
Our study aims to determine the incidence of TBI (active tuberculosis (ATBI) and latent tuberculosis (LTBI)) among patients with Crohn's disease (CD) receiving anti-TNF-α therapy.


For the period between June 2010 to December 2019, we performed a retrospective analysis of a total of 109 CD patients, screened before the start of biological treatment. Anti-TNF-α therapy was initiated by 97 patients, 74 of whom were retested for TBI during follow-up. All patients were BCG vaccinated.


Before starting biological treatment, we etablished LTBI in 11/109 (10.1%): 8/11 (72.7%) patients were TST (+) alone, 2/11 (18.2%) were IGRA (+) and TST (-), 1/11 (9.1%) were both IGRA and TST (+). Chest x-ray abnormalities were not detected in all 11 patients.
After prophylaxis with isoniazid (INH) 300 mg / daily for 9 months, 9/11 (83.3%) patients with LTBI reached treatment with an anti-TNF α agent. Of this group 7/9 (77.8%) patients were retested for TBI: 6/7 (85,7%) were TST and IGRA were (-), and one (14,3%) developed active pulmonary tuberculosis. Two patients were lost to follow up.
In the follow-up of patients under anti-TNF-α therapy, 74/97 (76.3%) patients were retested for TBI, with median duration of anti-TNF-a therapy was 24 (IQR 6-90) months.
A total of 16/74 (21.6%) patients were newly diagnosed with LTBI: 5/16 (31.3%) had TST conversion alone, 8/16 (50.0%) were TST(+) and IGRA (-), 1/16 6.3%) were both TST and IGRA (+), 1/16 (6.3%) had IGRA conversion alone, 1/16 (6.3%) were TST (-) and IGRA (+).
ATBI developed in 3/74 (4.1%) patients, one of them on the background of chemoprophylaxis with INH for LTBI. Median duration after the first dose of biologic therapy to detection of TBI was 12 (IQR 6-60) months.


This study instruct the clinician to be specifically vigilant when initiating anti-TNF-α therapy in IBD patients, because reactivation of TBI is a life-threatening complication in immunosuppressed patients.