Anti-integrin αvβ6 autoantibody in primary sclerosing cholangitis: a Japanese nationwide study

Background Although specific biomarkers for primary sclerosing cholangitis (PSC) are required, no such biomarkers have been identified. We previously reported that patients with PSC had anti-integrin alpha v beta 6 autoantibodies at only two hospitals. In this study, we aimed to validate the accuracy of the autoantibodies in diagnosing PSC using the newly developed Anti-integrin alpha v beta 6 enzyme-linked immunosorbent assay (ELISA) Kit, which enables quantitation and comparison of antibodies among different facilities. Methods Overall, 81 patients with PSC in a Japanese PSC registry recruited from 17 medical centers and hospitals, and 358 controls were enrolled. We retrospectively assessed anti-integrin alpha v beta 6 autoantibodies using the Anti-integrin alpha v beta 6 ELISA Kit and in-house ELISA. Results Anti-Integrin alpha v beta 6 ELISA Kit and in-house ELISA exhibited a significant correlation (r = 0.97, P < 0.001). Anti-integrin alpha v beta 6 autoantibodies were detected in 67 of 81 (82.7%) patients with PSC and 20 of 358 (5.6%) controls, resulting in a sensitivity of 82.7% and specificity of 94.4% for PSC, using the anti-integrin alpha v beta 6 ELISA Kit. When focusing on the presence or absence of inflammatory bowel disease (IBD), the sensitivities for PSC with ulcerative colitis, Crohn's disease, unclassified-IBD, and without IBD were 97.8% (43/44), 100% (1/1), 80.0% (8/10), and 53.8% (7/13), respectively. Antibody concentrations were significantly higher in PSC patients without IBD than in controls (P < 0.001). Conclusions We validated that anti-integrin alpha v beta 6 autoantibodies have high sensitivity and specificity for diagnosing PSC. This study provides further evidence that anti-integrin alpha v beta 6 autoantibodies are a useful biomarker for diagnosing PSC.