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P324 Tuberculosis infection under anti-TNF therapy – should we be looking for it?

S. Xavier*1,2,3, T. Cúrdia Gonçalves1,2,3, F. Dias de Castro1,2,3, J. Magalhães1,2,3, M. J. Moreira1,2,3, J. Cotter1,2,3

1Hospital da Senhora da Oliveira, Guimarães, Gastroenterology, Guimarães, Portugal, 2School of Medicine, University of Minho, Braga, Portugal, 3ICVS/3B’s Associate Laboratory, University of Minho, Braga/Guimarães, Portugal


Anti-tumour necrosis factor (TNF) therapy has revolutionised the treatment of inflammatory bowel disease. However, a major concern is the increased risk of developing tuberculosis (TB), which requires diagnosis and treatment of latent TB infection (LTBI) before initiation of anti-TNF agents. Currently, no recommendations exist regarding the need to regularly re-test patients for latent TB during treatment. We aimed to assess the incidence and to identify risk factors for newly acquired TB infection in patients under anti-TNF agents.


Adult patients under anti-TNF therapy for at least 12 months were retrospectively assessed. Patients with a negative pre-treatment interferon-γ releasing assay (IGRA) that repeated IGRA during anti-TNF treatment were reviewed. Patients with a pre-treatment positive IGRA were excluded.


Out of 244 patients under anti-TNF agents (124 infliximab, 120 adalimumab), 87 patients were included. Patients had a mean age of 40 ± 14 years, 64.4% were females, 93.1% were under infliximab and 64.4% had Crohn’s disease. Subsequent positive IGRA was identified in 9 patients (10.3% of our sample, 3.7% of all patients under anti-TNF therapy in our centre), of which 3 had active TB and 6 had LTBI.

When comparing patients with and without subsequent positive IGRA, no differences were found regarding age (39.6 vs. 36.7 years, p = 0.991) or gender (66.7% vs. 64.1% females, p = 0.999). Patients with subsequent positive IGRA have had close contact with patients with TB more frequently (22.2% vs. 0.0%, p = 0.010), however no differences were found regarding travels to TB-endemic areas (11.1% vs. 7.7%, p = 0.548), professional risk for TB infection (11.1% vs. 9.0%, p = 0.999), concomitant treatment with immunosuppressants (77.7% vs. 71.8%, p = 0.999), use of systemic steroids during anti-TNF treatment (33.3% vs. 35.9%, p = 0.999), diabetes mellitus (11.1% vs. 5.1%, p = 0.429) or active smoking (22.2% vs. 20.5%, p = 0.999). Furthermore, no differences were found in the duration of treatment at the time of subsequent IGRA (30.2 ± 26.7 vs. 42.5 ± 30.1 months, p = 0.640).


In patients under anti-TNF therapy, at least 3.7% of patients have a subsequent positive IGRA after treatment beginning. In our sample, only close contact with patients with TB was associated with a subsequent positive IGRA. Therefore, considering that infection during treatment is present in a non-negligible percentage of patients, and most of the classical risk factors cannot be used to identify at-risk patients, physicians may consider to routinely repeat IGRA in patients under anti-TNF therapy.