Time-course of adhesion molecule expression in rectal mucosa of gluten-sensitive subjects after gluten challenge

Adhesive interactions between endothelium and circulating cells, such as monocytes, neutrophils and lymphocytes, are crucial for localizing the inflammatory response. We investigated the inflammatory response of rectal mucosa to local gluten challenge as a dynamic model of antigen-induced tissue injury, during which the expression of adhesion molecules on leucocytes and endothelial cells could be sequentially observed. Expression of ELAM-1, ICAM-1 and VCAM-1 was monitored in 10 treated and eight untreated patients with gluten sensitivity (coeliac disease), and in five disease controls for up to 4 h (short challenge), while a further seven treated coeliacs were monitored for up to 24 h (long challenge) following rectal gluten challenge. In the former, the expression of VCAM-1 and ELAM-1 was significantly raised 4 h after gluten challenge compared with controls. VCAM-1 and ELAM-1 expression was also increased in mucosae of treated patients, but to a lesser extent. VCAM-1 expression continued to increase for up to 24 h after gluten, while ELAM-1 had begun to wane by 4 h, reaching basal levels by 24 h. In contrast, the expression of ICAM-1 did not change in any of the disease groups studied. These findings relate to significant increases in lymphocytes (CD3+ cells) after 8 h, and neutrophils (CD15+ cells) after 4 h in the lamina propria. This approach has permitted novel studies of the inflammatory response to a defined antigen in sensitized (gluten-sensitive) human patients.