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.