INHIBITORY EFFECT OF CETIRIZINE ON CYTOKINE-ENHANCED IN-VITRO EOSINOPHIL SURVIVAL

Background: Cetirizine is an antihistamine that inhibits in vivo eosin ophil influx into the inflamed airways following allergen challenge, a nd in vitro eosinophil chemotaxis and adhesion. Since eosinophils are proposed to have an important role in the pathophysiology of asthma an d allergic disease, the effects of cetirizine on eosinophil function m ay be a mechanism of this agent's therapeutic regulation of the allerg ic reaction. Objective: To determine the effect of cetirizine on in vi tro eosinophil survival. Methods: Using human eosinophils isolated fro m patients with allergic rhinitis, the cells were cultured in vitro fo r 48 to 72 hours with medium, cetirizine, or dexamethasone in the pres ence of IL-5, IL-3, or GM-CSF. Eosinophil survival was assessed by try pan blue exclusion. Results: In the presence of IL-5, but not GM-CSF o r IL-3, 100 mu M cetirizine significantly inhibited eosinophil surviva l at 48 and 72 hours; the magnitude of this inhibition was dependent o n cytokine concentration. Although cetirizine significantly suppressed cytokine promotion of eosinophil survival, it was not as potent as de xamethasone. Conclusions: Although the in vitro concentration of cetir izine was required to be quite high, cetirizine may affect in vivo air way inflammation through its inhibition of IL-5-dependent eosinophil s urvival.