Immune regulatory mechanisms of CD177+ neutrophils in the pathogenesis of inflammatory bowel disease

Abstract

Objective To examine CD177 expression in peripheral blood and inflamed mucosa from active patients with inflammatory bowel disease (IBD), and explore its potential role in regulating the migration of neutrophils. Methods Peripheral blood and inflamed intestinal mucosa were harvested from patients with active Crohn′s disease (n=18), active ulcerative colitis (n=21) and healthy controls (n=14). CD177 expression was determined by flow cytometry. CD177+ and CD177- neutrophils were also isolated from peripheral blood of patients with active IBD by immunomagnetic beads, and the migration of these neutrophils was analyzed by Transwell. Results CD177 expression was highly increased in peripheral blood neutrophils and inflamed mucosa from patients with active IBD compared with that in healthy controls (P<0.05). Purified CD177+ and CD177- neutrophils were isolated from active IBD patients, and a Transwell analysis revealed that the migration capacity of CD177+ neutrophils was markedly increased than that of CD177- neutrophils in all groups (P<0.05). Moreover, the migration capacity of CD177+ neutrophils from IBD patients was also markedly increased compared with that from healthy controls (P<0.05). Conclusion Our data demonstrate that CD177 expression is increased in patients with IBD, and that CD177 promotes neutrophil migration and homing into intestinal mucosa. CD177+ neutrophils may play an important regulatory role in modulating intestinal mucosal inflammation. Key words: Inflammatory bowel disease; Neutrophils; CD177; Inflammation