ALTERED EXPRESSION OF ALPHA-E-BETA-7 INTEGRIN ON INTRAEPITHELIAL AND LAMINA PROPRIA LYMPHOCYTES IN PATIENTS WITH CROHNS-DISEASE

Objective: To compare the expression of adhesion molecules on intestin al intra-epithelial (IEL) and lamina propria T cells (LPL) from ileum and colon, in patients with Crohn's disease (CD) versus healthy contro ls, with special reference for the alpha E beta 7 integrin. Methods: I EL and LPL were obtained from 18 CD patients and 20 controls by enzyma tic extraction, and subsequently characterized by now cytometry for CD 3, CD4, CD8, CD25, LFA-1 alpha (CD11a), CD44, alpha 4 and alpha E beta 7 integrin. Results: In LPL of controls, a decreased CD4/CD8 ratio wa s noted in ileum compared to colon. This regional difference was accom panied by a higher expression of alpha E beta 7 integrin in ileum vers us colon. In LPL from left hemicolon of CD patients, a decreased CD4/C D8 ratio was noted versus controls. alpha E beta 7 expression on T cel ls of LPL did not discriminate CD from controls. However, an overexpre ssion of this beta 7 integrin member was observed on CD25+ T cell subs ets from lamina propria of left hemicolon, in CD versus controls. More over, in IEL, profound alterations in alpha E beta 7 integrin were obs erved in CD, compared to controls. A decreased expression of alpha E b eta 7 was noted in IEL of ileum of CD patients. This was also apparent in non-inflamed mucosa. Conclusion: The observed changes of alpha E b eta 7 integrin expression in CD patients versus controls are of pathog enic relevance, especially the decreased expression of alpha e beta 7 in IEL of non-inflamed CD mucosa. This may be one of the earliest even ts in the pathogenesis of this disease.