Diversion of intestinal flow decreases the numbers of interleukin 4 secreting and interferon ã secreting T lymphocytes in small bowel mucosa

Background/Aims—The intestinal immune system faces large amounts of antigens, and its regulation is tightly balanced by cytokines. In this study, the eVect of intestinal flow diversion on spontaneous secretion of interleukin (IL)-4 and interferon (IFN)ã was analysed. Methods—Eight patients (two with Crohn’s disease, four with ulcerative colitis, and two with previous colon cancer) carrying a double lumen small bowel stoma after a total colectomy procedure were included in the study. For each patient, eight biopsy samples were taken endoscopically from both the diverted and non-diverted part of the small bowel. Intraepithelial lymphocytes (IELs) and lamina propria lymphocytes (LPLs) were isolated separately and assayed for numbers of cells spontaneously secreting IL-4 and/or IFN-ã by an ELISPOT technique. Results—Compared with the nondiverted mucosa, a significant decrease in the number of spontaneously IFN-ã secreting CD3 lymphocytes was observed in the diverted small bowel mucosa among both IELs (p = 0.008) and LPLs (p = 0.007). The same results, although less significant, were obtained for IL-4, especially in LPLs (p = 0.01). Conclusion—The intestinal content influences the spontaneous secretion of IFN-ã and IL-4 by intestinal lymphocytes. These results could help to elucidate the antiinflammatory role of split ileostomy in patients suVering from inflammatory bowel diseases.