Suppressive effects of azelastine hydrochloride on CD40 expression in mice

The present study was designed to examine the influence of an anti-allergic agent, azelastine hydrochloride (AZ) on a co-stimulatory molecule, CD40 expression in actively sensitized mice. BALB/c mice were sensitized by intraperitoneal injection of two doses of dinitrophenylated-ovalbumin and Al(OH)3 at one-week intervals. The mice were treated orally with 0.1 mg/kg of AZ once a day for 14 days starting the same day of booster sensitization. AZ treatment of mice caused the significant suppression of total serum IgE concentration on Day 21 after the first sensitization. However, AZ treatment scarcely affected IL-4 concentration in aqueous spleen extracts. Flowcytometric analysis revealed the suppressive effects of AZ on CD40 expression on sensitized-spleen cells. These data may suggest that AZ suppresses the production of IgE through the inhibition of CD40 expression.