Allergen-induced accumulation of eosinophils and lymphocytes in skin chambers is associated with increased levels of interleukin-4 and sVCAM-1.

Abstract

The aim of the study was to characterize the kinetic accumulation of various inflammatory mediators in allergen-challenged skin chambers applied on patients with pollen-related allergic rhinitis/mild asthma. Skin blisters were induced on the forearms and challenged with allergen or phosphate-buffered saline (PBS). Peripheral blood was drawn before and 8 h after challenge for analysis of differential cell counts, sVCAM-1, and alpha2-macroglobulin. Chamber fluids, collected at 1, 4, and 8 h after allergen application, were analyzed for differential cell counts, histamine, interleukin (IL)-4, sVCAM-1, and alpha2-macroglobulin. The number of recruited leukocytes was equal in allergen and PBS chambers; however, the numbers of eosinophils and lymphocytes were significantly (P< or =0.05) elevated in allergen-challenged chambers at 8 h. Compared to PBS chambers, allergen chambers contained significantly (P<0.01-0.05) higher levels of histamine (at 1 and 4 h), IL-4 (at 4 and 8 h), alpha2-macroglobulin (at 1 and 8 h), and sVCAM-1 (at 1 and 8 h). In contrast to alpha2-macroglobulin, levels of sVCAM-1 in peripheral blood were significantly (P<0.05) increased at 8 h. Increased levels of sVCAM-1 and IL-4 in allergen-challenged chambers, in parallel with increased recruitment of eosinophils and lymphocytes, points to the participation of IL-4 and VCAM-1 in the development of the late-phase reaction. Increased levels of sVCAM-1 in allergen-challenged chambers probably reflects a combination of leakage and local production.