Both Preoperative Perinuclear Antineutrophil Cytoplasmic Antibody and Anti-CBir1 Expression in Ulcerative Colitis Patients Influence Pouchitis Development After Ileal Pouch-Anal Anastomosis

Background & Aims: Acute pouchitis (AP) and chronic pouchitis (CP) are common after ileal pouch-anal anastomosis (IPAA) for ulcerative colitis. The aim of this study was to assess associations of preoperative perinuclear antineutrophil cytoplasmic antibody (pANCA) and anti-CBir1 flagellin on AP or CP development. Methods: Patients were assessed prospectively for clinically and endoscopically proven AP (antibiotic responsive) or CP (antibiotic-dependent or refractory to antibiotic therapy). Sera from 238 patients were analyzed for ANCA and anti-CBir1 using an enzyme-linked immunosorbent assay. pANCA⁺ patients were substratified into high-level (>100 EU/mL) and low-level (<100 EU/mL) groups. Results: After a median follow-up period of 47 months, 72 patients (30%) developed pouchitis. Pouchitis developed in 36% of pANCA⁺ patients versus 16% of pANCA^- patients (P = .005), 46% of anti-CBir1⁺ patients versus 26% of anti-CBir1^- patients (P = .02), and 54% of 35 pANCA⁺/anti-CBir1⁺ patients versus 31% of 136 pANCA⁺/anti-CBir1^- patients (P = .02). AP developed in 37 pANCA⁺ patients (22%) versus 6 pANCA^- patients (9%) (P = .02), and 12 anti-CBir1⁺ patients (26%) versus 31 anti-CBir1^- patients (16%) (P = .1). Although AP was not influenced by pANCA level, AP was seen in 38% of low-level pANCA⁺/anti-CBir1⁺ patients versus 18% low-level pANCA⁺/anti-CBir1^- patients (P = .03). CP was seen in 29% of high-level pANCA⁺ patients versus 11% of low-level pANCA⁺ patients (P = .03). Conclusions: Both pANCA and anti-CBir1 expression are associated with pouchitis after IPAA. Anti-CBir1 increases the incidence of AP only in patients who have low-level pANCA expression, and increases the incidence of CP only in patients who have high-level pANCA expression. Diverse patterns of reactivity to microbial antigens may manifest as different forms of pouchitis after IPAA.