Ganglionic tuberculosis in a Crohn’s disease patient treated by infliximab despite anti-tuberculosis chemoprophylaxis

Infliximab is an IgG1κ monoclonal antibody against tumor necrosis factor-α (anti-TNFα) who have significantly improved the management of patients with Inflammatory Bowel Diseases (IBD), but with an increased risk of opportunistic infection, especially tuberculosis (TB). We report a case of a 54 years-old man with an ileal Crohn’s disease (CD) diagnosed in July 2014 (Montreal classification at diagnosed: A2L1B1p-). Patient was an active smoker and was treated by budesonide for several flares. Two years after diagnosis, since he has been hospitalised for subocclusion treated with methylprednisolone, combination therapy by mercaptopurine and anti-TNFα was discussed for steroid dependence. Patient was screened for tuberculosis (TB). A latent tuberculosis (LTB) was highlighted based on a positive interferon-gamma release assay (QuantiFERON TB) without clinical, microbiological and radiological evidence of active disease. A nine-month course of isoniazid (INH) 300 mg/day was started 4 weeks before the combination therapy with thiopurine/infliximab at the recommended doses. This treatment allowed a clinical remission and thiopurine could be stopped. Six months after completing INH for LTB and 1 month after cessation of thiopurine, patient was admitted in our emergency department for fever, dyspnoea and cough. Chest tomography showed large lymphadenopathies in the right pulmonary hilum and in the mediastinum. A fibroscopy with a bronchoalveolar lavage (with looking for bacillus of Koch) and an endobronchial ultrasound with biopsies were performed, both negative. Finally, a diagnosis of ganglionic tuberculosis was settled by a positive microscopic exam (auramine coloration) on an excised cervical lymphadenopathy. No resistance to usual anti-tuberculosis treatment was highlighted. Infliximab was immediately discontinued and anti-tuberculosis 4-drug regimen was initiated. Patient received Vedolizumab as IBD treatment 1 month later and he did not present any recurrence of TB infection or new flare of Crohn's disease up until now. This case report emphasizes that chemoprophylaxis for LTB does not completely protect against reactivation of TB in IBD patients treated by anti-TNF. It could be useful to study risk factors for reactivation of LTB in this treated by biologics population (monotherapy or combination therapy) to establish a case-by-case monitoring.