Anti‐integrin αvβ6 Immunoglobulin G antibodies are detected in pediatric colonic Crohn's disease

OBJECTIVES: Anti-integrin αvβ6 Immunoglobulin G (anti-αvβ6 IgG) has been identified as a biomarker for ulcerative colitis (UC) in adults, but they were also detected in pediatric Crohn's disease (CD). We hypothesized that their less specificity in this population could reflect colonic inflammation rather than disease type and may be influenced by HLA-DQA1*05 carriage. METHODS: We conducted a monocentric retrospective study using serum and clinical data from 213 pediatric inflammatory bowel disease patients and 110 controls, analyzing the association between anti-αvβ6 IgG and disease location, clinical and endoscopic activity, and HLA-DQA1*05 status. RESULTS: Anti-αvβ6 IgG were detected in 80 of 105 patients (76%) with UC, 30 of 108 patients (28%) with CD, and 2 of 110 (2%) controls. In patients with CD, anti-αvβ6 IgG positivity was significantly higher in colonic or ileocolonic phenotypes (29/84; 35%) compared to ileal or upper gastrointestinal phenotypes (1/24, 4%) (p = 0.0035). No significant association was found between antibody positivity or levels and clinical, biochemical or endoscopic activity. Anti-αvβ6 IgG was detected in 73% of patients with UC and 23% of patients with CD in endoscopic remission. The HLA-DQA1*05 allele was more frequent in antibody-positive patients (78% vs. 56%, p = 0.005), though also more common in UC than CD (82% vs. 54%, p = 0.001). CONCLUSIONS: In our cohort, among patients with CD, anti-αvβ6 IgG autoantibodies were predominantly detected in those with colonic localization. This observation may support previous evidence of a shared immunological background between colonic CD and UC.