Second European evidence-based consensus on the prevention, diagnosis and management of opportunistic infections in inflammatory bowel disease

From genome wide association studies there is increasing evidence of an aberrant immune response in IBD. 4 Susceptibility loci involve both the innate and adaptive immune response towards a diminished diversity of commensal microbiota. 5 Description of the numerous mechanisms contributing to this dysimmunity is beyond the scope of this article. Despite evidence of defective mucosal immunity, there is no proof of a systemic immune defect in patients with IBD in the absence of concomitant immunomodulator therapy.