The experimental production of increased eosinophils in rat late-phase reactions.

The effects of peripheral eosinophilia on the intensity, kinetics and cellular characteristics of rat cutaneous late-phase reactions (LPR) have been investigated. Two distinct methods of inducing peripheral eosinophilia did not alter either the intensity or the kinetics of LPR produced by the intradermal injection of anti-IgE, Compound 48/80, or isolated mast cell granules. Hypereosinophilic animals exhibited increased numbers of tissue eosinophils in LPR tissue sites which correlated with the elevations in their respective peripheral eosinophil counts; however, the absolute number of eosinophils present, although significant, was not impressive (less than 10% of total). Our data suggest that, although rat LPR can be modulated to involve increased tissue eosinophils by increasing the numbers of peripheral blood eosinophils, no effects of these procedures on altering either the intensity or the kinetics of these reactions can be appreciated.