Novel Diagnostic Autoantibodies Against Endothelial Protein C Receptor in Patients With Ulcerative Colitis

There have been many reports on serologic autoantibodies in inflammatory bowel diseases (IBD),¹ consisting of ulcerative colitis (UC) and Crohn's disease (CD), and recently Kuwada et al² reported a new autoantibody against integrin αvβ6 with high sensitivity and specificity for UC. Concurrently, we had discovered autoantibodies against endothelial protein C receptor (EPCR) in Takayasu arteritis (TAK), which is sometimes complicated by UC.³ Interestingly, this autoantibody was found in most patients with TAK associated with UC, and we found that the positivity rate in patients with UC without TAK was also high, suggesting that anti-EPCR antibody is a candidate autoantibody useful for the diagnosis of UC.⁴ To clarify the diagnostic usefulness of anti-EPCR antibodies in patients with IBD and their relationship to several disease subphenotypes and their disease activities, we analyzed the serum samples from patients with IBD and non-IBD control subjects in Japan and the United States.