Inflammatory Bowel Disease in the Setting of Autoimmune Pancreatitis

Background: Despite scattered case reports, the prevalence of inflammatory bowel disease (IBD) in patients with autoimmune pancreatitis (AIP) is unknown. We sought to better characterize the Putative association between the conditions. Methods: Medical records of 71 patients meeting accepted criteria for AIP were reviewed to identify those with endoscopic and histological evidence of IBD. Colon samples in patients with both AIP and IBD were immunostained to identify IgG4-positive cells. Results: Four patients with AIP (5.6%) had a diagnosis of IBD: 3 had Ulcerative colitis (UC) and 1 had Crohn's disease (CD). The diagnosis of IBD preceded or was Simultaneous to that of AIR Two AIP-UC patients treated for AIP with prednisone had a recurrence of AIR and 1 required 6-mercaptopurine for long-term corticosteroid-sparing treatment. Two AIP-IBD patients underwent Whipple resections, and 1 had recurrent AIP. All 3 patients with UC presented with pancolitis. and 2 required colectomy. Colon samples front 1 patient with UC and 1 patient with CD were available for review. Increased numbers of IgG4-positive cells (10 per high-power field) were noted oil the colon sample from the patient with UC. Conclusions: Almost 6% of patients with proven AIP had a diagnosis of IBD, compared to a prevalence of approximate to 0.4%-0.5% in the general population, potentially implying a 12-15-fold increase in risk. Patients with both AIP and IBD may have increased extent and severity of IBD. The finding of IgG4-positive cells oil colon biopsy suggests that IBD may represent in extrapancreatic manifestation of AIR