Serological Remission Defined by Anti-Integrin αvβ6 Antibody Predicts Long-Term Clinical Remission of Ulcerative Colitis

Background and Aims: Although management of ulcerative colitis (UC) has advanced with the treat-to-target strategy, biomarkers for relapse remain limited. The anti-integrin αvβ6 (V6) antibody reflects epithelial injury and could be a serological biomarker in UC. This retrospective cohort study evaluated whether the V6 antibody can predict relapse and be a serological target for sustained clinical remission. Methods: We measured V6 antibody levels in serum samples from patients with UC in clinical remission who had ≥3 years of follow-up. Relapse was defined as the need for initiation or modification (dose adjustment or switching) of systemic corticosteroids or molecular targeted drugs, or surgical intervention, due to worsening of disease activity (Lichtiger index ≥4). The ability of the V6 antibody to predict relapse and the cutoff value were investigated. Longitudinal intraindividual stability of the antibody level was evaluated. Results: Fifty-three of 149 patients experienced relapse. Seven and 2 patients required hospitalization and colectomy, respectively. The 1-year, 2-year, and 3-year cumulative relapse rates were 12.1%, 22.2%, and 32.9%, respectively. V6 antibody levels were significantly higher in patients who relapsed. Receiver-operating characteristic curve analyses showed considerable predictive ability (area under the curve, 0.73) at 1 to 3 years. The optimal cutoff for predicting 1-year relapse was 11.99U/mL, while ≤4.23U/mL yielded the highest 3-year negative predictive value. Cumulative 1-year, 2-year, and 3-year relapse rates were 0.0%, 0.0%, and 8.8%, respectively, in patients with ≤4.23U/mL. V6 antibody levels remained stable intraindividually and decreased on molecular-targeted therapy. Conclusion: The V6 antibody predicted long-term clinical remission of UC. The definition of serological response (≤11.99U/mL) and remission (≤4.23U/mL) based on this antibody potentially serves as a noninvasive therapeutic target in UC.