Inborn errors of immunity (IEI) are genetic disorders causing immune dysregulation, often increasing susceptibility to infections, autoimmunity, and inflammation. 30% of patients with predominant autoimmune/autoinflammatory IEI present with gastrointestinal symptoms suggestive of inflammatory bowel disease (IBD). IEI-associated inflammatory bowel disease (IEI-IBD) can mimic classic IBD. Treatment for IEI-IBD is not well-established. This study aims to assess the prevalence, clinical and endoscopic presentations, and treatment outcomes of IBD in IEI patients.
This is a single-center, retrospective study. All patients were ≥14 years of age with a confirmed diagnosis of IEI and IBD based on clinical, endoscopic, and histologic evaluations. Primary outcomes included the prevalence and clinical and endoscopic characteristics. The 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 the 19 patients who underwent endoscopy, abnormalities were observed in 9 (47.4%), with ulcerations being the most common finding (33.3%). The 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 was noted in 5 patients (55.5%), while only one (11.1%) had a family history of IBD. Chronic diarrhea (88.9%) was the most common clinical presentation. Initial fecal calprotectin levels were >250 in all patients. Radiological abnormalities such as strictures, fistulas, perianal disease, and abscesses were reported in 5 patients (55.5%). Medical treatment included corticosteroids in 33.3% (n = 3), immunosuppressants in 22% (n = 2), biologics including vedolizumab, Infliximab, and Adalimumab in 33.3% (n = 3), and 1 patient received no IBD-specific treatment. Clinical response was noted in 3 patients (1 on corticosteroids and 2 on immunosuppressants), with no improvement in those who received biologics. No correlation was found between low baseline lymphocyte marker counts or immunoglobulin levels and lack of clinical response. Surgery related to IBD was required in 2 patients (22.2%).
The prevalence of IEI-IBD in our cohort is low. Characteristics include young age, positive family history of IEI, chronic diarrhea, and abdominal pain. Both intestinal and colonic involvements were noted during endoscopy, with Crohn’s disease being the most common IBD subtype. The success of therapy in our cohort was limited and did not correlate with baseline lymphocyte marker counts or immunoglobulin levels. 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.
