Increased expression of laminin/collagen receptor (VLA-1) on epithelium of inflamed human intestine.

Immunohistochemical techniques were used to investigate the epithelial expression of VLA-1 in inflammatory bowel disease in six patients with Crohn's disease, in four patients with ulcerative colitis, and in one patient with indeterminate colitis, and compared with that in the small intestine and colons of 10 normal controls. In normal small bowel VLA-1 was expressed on crypt epithelial cells and only weakly or not at all on surface epithelium. VLA-1 was again expressed weakly in normal colon, except in one case, a 1 year old child with diarrhoea but no histological abnormalities. In small and large intestine affected with Crohn's disease, ulcerative colitis, or indeterminate colitis, there was increased expression of VLA-1 on the basolateral aspects of crypt cells and de novo expression on surface epithelium. It is suggested that this is an adaptive response to prevent epithelial cell loss as a result of inflammation in the underlying lamina propria.