CROHNS-DISEASE AND ULCERATIVE-COLITIS MUCOSAL T-CELLS ARE STIMULATED BY INTESTINAL EPITHELIAL-CELLS - IMPLICATIONS FOR IMMUNOSUPPRESSIVE THERAPY

Background. Crohn's disease (CD) and ulcerative colitis (UC) are chron ic inflammatory diseases, and their pathogenesis is attributed in part to alterations of the mucosal immune system. This study was designed to define the possible contribution of epithelial cells to the activat ion of lamina propria T lymphocytes (LPTs) in CD and UC. Methods. LPTs isolated from CD, UC, and control surgical specimens were cocultured with freshly isolated allogeneic or autologous epithelial cells or epi thelial cell lines. Resulting T-cell proliferation was evaluated by tr itiated thymidine incorporation on day 5. Results. When intestinal epi thelial cells were used to stimulate mucosal T-cell proliferation, CD and UC LPTs were less responsive than conrol LPTs (p < 0.05 and p < 0. 03 respectively). This difference between inflamed and control T cells was consistently observed by using a variety of different intestinal epthelial cell types. Conclusions. CD and UC mucosal T cells are hypor esponsive to activation by intestinal epithelial cells when compared w ith control LPTs. Elucidating the mechanism underlying the differentia l activation of CD and UC LPTs may help to better understand the immun opathogenesis of these conditions.