In-situ endothelial cell adhesion molecule expression in ulcerative colitis. E-selectin in-situ expression correlates with clinical, endoscopic and histological activity and outcome.

BACKGROUND AND OBJECTIVES

Little is known of the in-situ expression of adhesion molecules in ulcerative colitis (UC) according to disease activity. In the present study we investigate the vascular expression of endothelial leucocyte adhesion molecule 1 (ELAM-1/E-selectin), vascular cell adhesion molecule (VCAM-1) and intercellular adhesion molecules (ICAM-1 and ICAM-3) on the rectal mucosa of patients with UC in order to identify links between in-situ expression of these adhesion molecules and clinical, endoscopic and histological parameters.

DESIGN AND METHODS

At inclusion, 16 untreated patients with UC at different stages of disease activity were assessed clinically and endoscopically and underwent rectal biopsy. Ten patients had similar assessments during follow-up. Quantitative histological and immunohistochemical scores were established with anti-E-selectin, VCAM-1, ICAM-1, ICAM-3 and HLA-DR monoclonal antibodies on frozen biopsy specimens.

RESULTS

(1) At inclusion, E-selectin in-situ expression correlated with clinical activity (r = 0.7, P = 0.05), endoscopic severity (r = 0.74, P = 0.04), the histological score (r = 0.57, P = 0.02) and in-situ expression of HLA-DR on epithelial cells (r = 0.74, P = 0.01). (2) After remission, there was a significant decrease in ELAM-1 in-situ expression (P = 0.04). (3) In patients with clinical, endoscopic and histological remission the level of residual E-selectin expression appeared to be predictive of clinical relapse. (4) Vascular expression of VCAM-1 and ICAM-1 did not correlate with clinical, endoscopic or histological parameters, or with changes in disease activity. (5) ICAM-3 was never detected on endothelial cells of the colonic mucosa of controls or patients with UC.

CONCLUSION

In ulcerative colitis, E-selectin, but not VCAM-1, ICAM-1 or ICAM-3, appears to play a central role in leucocyte migration into the colonic mucosa. Elevated vascular expression of E-selectin after remission may be involved in clinical recurrence.