D1.313 - Inborn Error of Immunity Associated Inflammatory Bowel Disease at a Tertiary Care Center

Inborn errors of immunity (IEI) are genetic disorders causing immune dysregulation, often increasing susceptibility to infections, autoimmunity, and inflammation.  IEI-associated inflammatory bowel disease (IBD) can mimic classic IBD. Treatment for IEI-associated IBD is not well-established. This study aims to assess the prevalence, clinical and endoscopic presentation, and treatment outcomes of IBD in IEI patients.

This is a single center, retrospective study. Patients were ≥ 14-years of age with a confirmed diagnosis of IEI-IBD based on clinical, endoscopic, and histologic evaluations. Primary outcomes included the prevalence, clinical and endoscopic characteristics. Secondary outcomes included IBD treatment response and safety.

Among 390 patients with IEI 36 (18.7%) exhibited gastrointestinal symptoms, with diarrhea being the most prevalent symptom (69.3%,n=25). In 19 patients who underwent colonoscopy, abnormalities were observed in 9 (47.4%) with ulcerations being the most common finding (33.3%). Prevalence of IEI-associated IBD was 2.3% (n=9), with the most prevalent being CD (55.5%,n=5), followed by UC and IBD-unclassified (22.2%,n=2). Family history of IEI noted in (55.5%, n=5), while only (11.1%,n=1) had family history of IBD. Colonoscopy was performed on 8 patients (89%), of those (66.7%,n=6) had abnormal finding.Medical treatment included corticosteroids 33.3% (n=3), immunosuppressants in 22% (n=2), biologics in 33.3% (n=3)Clinical response noted in 3 patients, with no improvement in those who received biologics. One patient had cytomegalovirus (CMV) colitis and four developed bacterial infections (none were on biologics).The mortality rate among was 44.4%, with no significant associations between mortality and factors including gender, history of bacterial GI infections, extra-GI autoimmune disease, age at diagnosis.

Prevalence of IEI-IBD was low but is associated with high mortality. Success of therapy was limited. Further investigation involving larger cohorts of patients with IBD, particularly those exhibiting high-risk features (early onset, recurrent infections, and multiple autoimmunities) is necessary to identify individuals with inborn errors of immunity.