Anti-integrin αvβ6 antibody levels in serum samples of patients with ulcerative colitis (UC) who received restorative proctocolectomy (RPC) with ileal pouch-anal anastomosis. Serum immunoglobulin (Ig) G antibodies against integrin αvβ6 were quantified by enzyme-linked immunosorbent assay. A, Changes of serum anti-integrin αvβ6 antibody levels in 13 patients with UC after RPC. The serum anti-integrin αvβ6 antibody levels at 3, 9, and 12 months after RPC were significantly lower than those at the time of RPC (3 out of 16 patients were excluded from the analysis as serum samples at 3, 6, and 9 months after RPC were not available). *P < .05, Wilcoxon matched-pairs signed-rank test. P = .0398, .2163, .0215, and .0042 (0 vs 3, 6, 9, and 12 months after RPC, respectively). B, Overall change of the serum anti-integrin αvβ6 antibody levels after RPC (n = 16). Patients UC3, UC4, UC5, UC8, UC9, and UC11 developed pouchitis, while the remaining patients did not develop pouchitis. The serum anti-integrin αvβ6 antibody levels in patients who developed pouchitis remained high. C, Comparison of the serum anti-integrin αvβ6 antibody levels at the time of RPC between patients who developed pouchitis and those who did not. The serum antibody levels in patients who developed pouchitis were significantly higher than those in patients who did not develop pouchitis at the time of RPC (n = 16). *P < .05, Mann-Whitney U test. P = .0225.