P0691 DOES THE ASSOCIATION WITH AN AUTOIMMUNE DIGESTIVE DISEASE DEFINE AN AUTOIMMUNE COLITIS?

Introduction:The pathogenesis of inflammatory bowel disease (IBD) is thought to be in part autoimmune (AI) because of frequent association of IBD with other AI diseases.To test the hypothesis that ulcerative colitis (UC) associated with autoimmune diseases may have some particular clinical, biological and histological features that would differentiate them from typical UC, we undertook the following retrospective study.Methods: Among the 110 patients with inflammatory colitis followed in our unit, we individualized a subset of patients with associated autoimmune diseases (group 1).We analysed the clinical presentation, the endoscopic and histological features, and the outcome.The histological features of this subgroup were compared with those of 10 patients with typical UC without AI disease (group 2).The mean follow up was 5y (18m-16y).Results: Fourteen patients (9 girls) were studied.Two had an AI family history.Thirteen had a sclerosing cholangitis (SC), 6 had several AI diseases ( 3 SC+AI hepatitis, 2 SC+celiac disease, 1 AI hepatitis +stomatitis+circulating anticoagulant).The median age at onset of IBD was 10y 9m (3-19y).The diagnosis of IBD was made before the liver disease in 1 case, after in 7 cases and at the same time in 6 cases.The clinical symptoms were diarrhea in 85%(12), rectal bleeding in 28%(4), abdominal pain in 28%(4), isolated anaemia in 7%(1); one child was asymptomatic.pANCA were positive in 85%, antinuclear antibodies (Ab) in 54%, anti smooth muscle Ab in 54%, and 69% had at least 1 positive auto-Ab (different from pANCA).Endoscopy was normal in 3 cases, and showed a pancolitis in 11 cases ; the ileum was always normal and the rectum was spared in 85%.The specific histological findings were : a pseudovillous aspect in the colon of group 1 more frequent than in group 2, very few ulcerations and crypt abscesses in group 1 compared with group 2, and a moderate chorionic infiltration with predominance of eosinophils in group 1, against a denser infiltration with predominance of neutrophils in the group 2.During the follow up no patient underwent colectomy.Nine patients (78%) were controlled with non-steroid anti-inflammatory drugs, 42% needed one course of steroids, and only 3 of them still need steroids; 3 patients are treated with azathioprine, 2 of them for AI hepatitis.Conclusion: Phenotype of UC+AI is distinct from the typical UC or Crohn's colitis: a rather mild pancolitis with rectal sparing , specific histological pictures, and association with auto-Ab.Further studies are needed to establish the immunological features of these patients.