Factors Related to the Presence of IgA Class Antineutrophil Cytoplasmic Antibodies in Ulcerative Colitis

Abstract

Objectives: Few studies have assessed the IgA antineutrophil cytoplasmic antibody (ANCA) positivity in ulcerative colitis patients and there is no information about factors related to its synthesis and its status after colectomy. The aims of the study were to assess the serum IgA ANCA prevalence in ulcerative colitis patients, both nonoperated and operated, and to determine the clinical factors related to this positivity. Methods: Fifty-four ulcerative colitis patients, 63 ulcerative colitis colectomized patients (32 with Brooke’s ileostomy and 31 with ileal pouch anal anastomosis), and 24 controls were studied. Antineutrophil cytoplasmic antibodies were detected by specific indirect immunofluorescent assays. Results: The percentage of IgA ANCA was significantly higher in patients with ileal pouch anal anastomosis (45%) than in patients with Brooke’s ileostomy (22%). There were no differences related to the presence of pouchitis in ileal pouch anal anastomosis patients. Patients with nonoperated extensive colitis (47%) had a significantly higher percentage of IgA ANCA than patients with proctitis (19%). Total percentage of ANCA (IgA and/or IgG) tended to be higher in ulcerative colitis and in patients with ileal pouch anal anastomosis than in patients with Brooke’s ileostomy. However, in ileal pouch anal anastomosis patients, ANCA positivity was mainly due to exclusive IgA production. Conclusions: A substantial percentage of ulcerative colitis patients, and especially colectomized patients with ileal pouch anal anastomosis, had IgA ANCA, suggesting that ANCA production in ulcerative colitis might be stimulated by an immune reaction in the intestinal mucosa.