It is thought that the intestinal injury seen in inflammatory bowel disease (IBD) is related to an excessive immune response to gut microbiota, mediated by the activation of CD4+ T helper (Th) cells. Regulatory T cells (Tregs) are believed to suppress further inflammatory cell activity. Many different regulatory T cell abnormalities have been reported in IBD, and there is currently no consensus as to the relationship between different Treg populations and disease pathogenesis. We sought to perform a comprehensive evaluation of multiple Treg subpopulations in paired mucosal and blood samples from IBD patients of differing ethnic and cultural backgrounds and to relate it to disease activity and severity.
A total of 63 subjects (39 with Crohn’s disease, 8 with ulcerative colitis and 17 controls) were recruited from the Concord Repatriation General Hospital, Sydney, Australia. Another 54 subjects (21 with Crohn’s disease, 24 with ulcerative colitis and 9 controls) were recruited from the University of Malaya Medical Centre, Kuala Lumpur, Malaysia. Blood samples and colonic mucosal biopsies as well as clinical information were obtained. Prior to analysing these samples we designed and tested several multi-parameter flow cytometric panels on blood and mesenteric lymph nodes isolated from surgically resected tissue of IBD patients. The panels were designed to detect co-expression of chemokine and tissue homing receptors in combination with transcription factors associated with regulatory and/or T helper cell differentiation. Results for 8- and 12-colour panels will be presented.