ENDOTHELIAL ADHESION MOLECULES FOR NASAL-HOMING T-CELLS IN ALLERGY

During the allergic reaction mucosal T cells are activated and a local increase in numbers occurs. In peripheral blood, a concomitant T cell activation and switch towards memory phenotype appears. E-selectin, i ntercellular adhesion molecule (ICAM)-1 and vascular cell adhesion mol ecule (VCAM)-1 were studied in nasal mucosal biopsies taken during a t ime-course provocation study, including patients with seasonal allergi c rhinitis and healthy controls. Allergic patients were also studied d uring the natural pollen season with particular attention to the influ ence of local corticosteroid treatment. Before provocation allergic pa tients and controls did not differ concerning the expression of endoth elial adhesion molecules. However, the epithelial ICAM-1 expression wa s increased among allergies (P<0.05). Repetitive allergen provocation induces an increased endothelial expression of VCAM-1 in allergic pati ents (P<0.01). Similarly, VCAM-1 expression was increased during the n atural pollen season (P<0.05). Interestingly, the increased VCAM-1 exp ression was inhibited by the use of local corticosteroids. The present data demonstrate a putative integrin-VCAM-1 mechanism for selective h oming of T memory cells to the allergic nasal mucosa and new in vivo e ffects of local corticosteroid treatment are demonstrated.