EFFECT OF CETIRIZINE ON HUMAN EOSINOPHIL SUPEROXIDE GENERATION, EOSINOPHIL CHEMOTAXIS AND EOSINOPHIL PEROXIDASE IN-VITRO

Cetirizine, a potent H-1-antagonist, has been reported to inhibit eosi nophil migration into human skin. We, therefore, further evaluated the effect of cetirizine on eosinophil function, including superoxide ani on generation, chemotaxis, and eosinophil peroxidase (EP) release. In allergic subjects, superoxide anion generation 60 min after platelet-a ctivating factor (PAF) activation was inhibited by concentrations of c etirizine ranging from 0.01 to 1 mu g/ml (2.612 x 10(-8) to 2.612 x 10 (-6) M). No significant inhibition was observed in normal subjects. PA F (10(6) M)-induced eosinophil chemotaxis was also inhibited by cetiri zine. In allergic subjects, percent inhibitions were 47.5+/-6.1% at 0. 01 mu g/ml, 50.8+/-5.1% at 0.1 mu g/ml and 58.9+/-6.4% at 1 mu g/ml of cetirizine. In allergic subjects, N-formyl-methionyl-lencyl-phenylala nine induced eosinophil chemotaxis was inhibited by cetirizine, althou gh EP release was not. These results suggest cetirizine has effects on eosinophils which can not be explained by H-1-blockade alone.