ALTERED EXPRESSION OF CELL-ADHESION MOLECULES IN UNINVOLVED GUT IN INFLAMMATORY BOWEL-DISEASE

Adhesion of circulating cells to vascular endothelium occurs in the ea rly phase of inflammation, and is mediated by specific cell adhesion m olecules. Many such adhesion molecules are increased in inflamed regio ns of ulcerative colitis (UC) and Crohn's disease (CD) but there is li mited knowledge of their expression in the uninvolved gut, adjacent to inflammation. We investigated immunohistochemically the expression of platelet endothelial cell adhesion molecule-1 (PECAM-1), intercellula r adhesion molecule-1 (ICAM-1) and lymphocyte function-associated anti gen-1 (LFA-1) on resected specimens taken at a distance of 2-4 cm from the inflamed area and without histological signs of inflammation. Com pared with normal gut, we found (i) a significant increase of PECAM-1- positive vessels in the mucosa of uninvolved UC (149.0+/-24.1 vessels/ mm2 (mean+/-s.d.); normal colon=123.1+/-21.6;P=0.004);(ii) a significa nt decrease of ICAM-1-positive vessels in uninvolved CD (111.9+/-22.6 vessels/mm2; normal ileum=136.9+/-27.6; P=0.04); and (iii) a moderate but statistically insignificant increase of LFA-1-positive cells in th e mucosa of uninvolved UC and Crohn's ileitis. This altered expression of cell adhesion molecules may contribute to the early lesion in infl ammatory bowel disease and provide new therapeutic opportunities.