PROSPECTIVE EVALUATION OF NEUTROPHIL AUTOANTIBODIES IN 500 CONSECUTIVE PATIENTS WITH INFLAMMATORY BOWEL-DISEASE

Previous studies have shown antineutrophil cytoplasmic autoantibodies (ANCA) in patients with inflammatory bowel disease (IBD). A particular subclass, the so-called 'atypical' (perinuclear) p-ANCA type, occurs in the majority of patients with ulcerative colitis. The purpose of th is prospective study was to assess, in a blinded fashion, this 'subcli nical' serological marker in a consecutive series of IBD patients. Fiv e hundred patients were evaluated, including 247 patients with ulcerat ive colitis and 253 with Crohn's disease involving the small and/or la rge intestine. Overall, 194 (38.8%) of all patients with IBD were posi tive, including 164 (66.3%) with ulcerative colitis and 30 (11.9%) wit h Crohn's disease. Except for coexistent sclerosing cholangitis, no ot her clinical or laboratory variable had an effect an the rate of ANCA detection. This is the largest single study of ANCA in patients with I BD and the only study to provide data solely from a single Canadian ce ntre. Results emphasize the immunopathological differences between ulc erative colitis-and Crohn's disease, and indicate that bath disorders are heterogeneous inflammatory disease processes.