Bacillus Calmette-Guerin (BCG)

BCG was used as a vaccine to prevent tuberculosis (TB). Because it is a form of TB it is relevant again because patients whose immune system is being suppressed by medication are susceptible to effects of BCG that is used now to treat bladder cancer.

Scope

Bulgarian GI study

Among all European Union countries, Bulgaria is one of the leaders in the incidence of TBI – 20.6/100,000 inhabitants. [1]

Before starting biological treatment, established LTBI was established in 11/109 (10.1%): 8/11 (72.7%) patients were TST positive, 2/11 (18.2%) were IGRA positive and TST negative, 1/11 (9.1%) was both IGRA and TST positive. Chest X-ray abnormalities were not detected in all 11 patients. The median induration (not erythema) diameter of TST among this group of patients was 10 (IQR 7-23) mm. 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 monitored and retested for TBI: 6/7 (85.7%) in the follow-up TST and IGRA were negative, and one (14.3%) developed ATBI (Active pulmonary tuberculosis), despite chemoprophylaxis for LTBI with INH. [1]

In patients undergoing biological therapy with previous negative screening test for tuberculosis, 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 positive and IGRA negative, 1/16 6.3%) were both TST+ and IGRA pos. 1/16 (6.3%) had IGRA conversion alone, 1/16 (6.3%) were TST negative and IGRA positive. TheMedian induration was 8 mm. [1]

BCG

Since 1951, BCG vaccination is mandatory in Bulgaria. The latter is applied within the first 24 hours after birth, achieving a high coverage rate. Nevertheless, Bulgaria is one of the leading countries in Europe in terms of tuberculosis incidence, unlike other countries on the continent where BCG vaccine has not been used for decades without an increase in morbidity. Several authors point out that BCG vaccination affects the high incidence of false-positive TSTs among this group of patients. [1]

Risk with tnfi drugs

Several studies have found that LTBI reactivation is observed within 3 to 6 months of initiation of anti-TNF-α therapy. A meta-analysis of 128 studies in countries with low, medium and high incidence of TBI, revealed that 73% of IBD patients treated with anti- TNF agents, despite negative screening results, developed active tuberculosis infection (ATBI).

Recommendations

Cytoplasmic pattern from ANA Patterns