Biomarkers predictive of responsiveness to integrin beta7 antagonists, including anti-beta7 integrin subunit antibodies, and methods of using such biomarkers are provided. In addition, methods of treating gastrointestinal inflammatory disorders such as inflammatory bowel diseases including ulcerative colitis and Crohn's disease are provided. Also provided are methods of using such predictive biomarkers for the treatment of inflammatory bowel diseases including ulcerative colitis and Crohn's disease.
