CCR9 and inflammatory bowel disease: For instance, Tregs express gut-homing receptors such as α4β7 and C-C motif chemokine receptor 9 (CCR9) to modulate inflammatory bowel disease (IBD), whereas C-X-C motif chemokine receptor 3 (CXCR3), the chemokine receptor for CXCL10, is crucial for migration to Th1-driven inflammatory sites like the islets (13, 17, 18).