Background-Vascular endothelial Eselectin expression is induced by proinflammatory cytokines and contributes to accumulation of leucocytes in tissues. Aims-To investigate the role of E-selectin in inflammatory bowel disease (IBD).Methods-E-selectin expression was assessed in patients with ulcerative colitis and Crohn's disease by measuring the concentration of circulating soluble E-selectin (sE-selectin) using ELISA, by immunohistochemistry of colonic biopsy specimens, and by abdominal immunoscintigraphy after injecting radiolabelled F(ab') 2 fragment of a monoclonal anti-Eselectin antibody. The value of scintigraphy using anti-E-selectin was judged by a prospective comparative study of autologous leucocyte scanning and E-selectin antibody scanning in 17 patients with IBD. Results-Circulating sE-selectin was elevated in patients with clinically active disease. Tissue expression of E-selectin was enhanced in patients with active inflammation, with weak or absent expression in inactive disease and healthy controls. In-111 labelled anti-E-selectin scintiscans were compared with Tc-99m labelled leucocyte scans performed 24 hours earlier. Twelve patients had areas of active inflammation on leucocyte scan while 11 patients had positive E-selectin scans. The results of the two scans were concordant in 14 patients, with those positive for both (10/17) showing similar disease localisation and extent. Conclusions-Tissue E-selectin and circulating sE-selectin are increased during active inflammatory bowel disease. Anti-E-selectin imaging with radiolabelled monoclonal antibody identified areas of inflammation in Crohn's disease and ulcerative colitis. The technique should prove useful clinically for identifying the site and extent of disease. (Gut 1998;43:40-47) Keywords: E-selectin; inflammatory bowel disease; Crohn's disease; ulcerative colitisThe vascular endothelium is an active participant in inflammatory processes. The response of endothelial cells to a variety of proinflammatory stimuli includes synthesis and expression of a number of cell surface antigens, 1 many of which are also released into the bloodstream. E-selectin is a 115 kDa glycoprotein which is expressed on the luminal surface of endothelial cells in response to proinflammatory cytokines such as interleukin 1 (IL-1) and tumour necrosis factor (TNF), or bacterial lipopolysaccharide, and plays a major role in facilitating the emigration of leucocytes into the tissues. 2-4Accumulation of polymorphonuclear leucocytes from the circulation into the gut wall is an integral component of the inflammatory process in the chronic inflammatory bowel diseases (IBD), ulcerative colitis, and Crohn's disease. E-selectin expression has been shown immunohistochemically in areas of active involvement of the gut.5-8 As expression of E-selectin is limited to activated endothelium, 9 10 this molecule provides a potential target for in vivo detection and quantitation of disease activity.Recent studies using animal models of inflammation have shown that intravenously ...

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