Local ocular immunotherapy for experimental allergic conjunctivitis

Purpose: We studied the efficacy of eyedrops as local ocular immunotherapy against experimental allergic conjunctivitis. Methods: Guinea pigs were sensitized with an intraperitoneal injection of ovalbumin (OA). Three weeks after the sensitization, a low concentration (10 mug/mL) of OA eyedrops was administered once a day for 3 weeks. Six weeks after the sensitization, an allergic inflammation was provoked with 20 mg/mL of OA eyedrops. Results: In conjunctival clinical scores 30 minutes after the allergen challenge, there was no significant difference between the controls and the treated group. The total number of inflammatory cells in the conjunctiva 8 hours after the allergen challenge was significantly decreased in the treated group (60.8 +/- 23.2 cells/field) compared with the control group (199.1 +/- 83.4 cells/field). Eosinophils in the conjunctiva 24 hours after the allergen challenge were also significantly decreased in the treated group (22.1 +/- 15.5 cells/field) compared with the control group (50.3 +/- 15.0 cells/field). Conclusions: In this study, local ocular immunotherapy mainly suppressed the late phase reaction of allergic inflammation. These results coincide with previous studies of immunotherapy in which a subcutaneous injection was used. Local ocular immunotherapy is effective against experimental allergic conjunctivitis. (C) 2000 Japanese Ophthalmological Society.