Prevention of allergic eye disease by treatment with IL-1 receptor antagonist.

PURPOSE: To determine the impact of interleukin-1 (IL-1) inhibition using IL-1 receptor antagonist (IL-1Ra) in a mouse model of allergic eye disease.
METHODS: A/J mice sensitized and challenged with cat dander in the eye were treated with topical IL-1Ra or vehicle alone. Control mice were treated with IL-1Ra or vehicle but sensitized and challenged with phosphate-buffered saline alone. Immediately after the final allergen challenge, the mice were observed for behavioral changes and assessed for lid injection and chemosis. The animals were then killed, eyes and attached lids were removed for either RNA extraction or histology, and draining lymph nodes were removed for either RNA extraction or in vitro stimulation assays. Differences in chemokine message between experimental and control groups-were determined by RNase protection assays.
RESULTS: Treatment with IL-1Ra in allergen-challenged animals significantly reduced allergen-induced changes in photosensitivity (60%, P = 0.0002), chemosis (50%, P = 0.0151), and injection (86.7%, P = 0.0068) compared with vehicle-treated controls. Interleukin-1Ra reduced the number of degranulated mast cells and caused a significant reduction in the number of eosinophils infiltrating the conjunctival matrix (P<0.001) after allergen challenge. Examination of chemokine mRNA taken from the conjunctiva and draining lymph nodes by RNase protection assay showed a profound decrease in the production of a number of C-C chemokines.
CONCLUSIONS: These findings suggest that IL-1Ra is suppressing allergic eye disease by a down-modulation of the recruitment of eosinophils and other inflammatory cells essential for the immunopathogenesis of ocular atopy.