IL-4-INDUCED MIGRATION OF EOSINOPHILS IN ALLERGIC INFLAMMATION

T lymphocytes present in allergically inflamed tissue synthesize and s ecrete the cytokines IL-3, IL-4, IL-5 and GM-CSF which may act as chem otaxins on eosinophils. In contrast to the former cytokines, IL-4 is c hemotactic only for eosinophils from peripheral blood of patients with atopic dermatitis and not for eosinophils from normal individuals. IL -4 has the same chemotactic potency as the other cytokines. The optima l chemotactic potency is reached at a concentration of 10 nM. In contr ast, neutrophils do not respond chemotactically to IL-4. Checkerboard analysis, inhibition studies with monoclonal anti-IL-4. Abs and desens itization experiments indicated specific interaction of IL-4 with eosi nophils. In eosinophils from normal individuals, IL-4 responsiveness c ould be induced by pretreatment of the cells with IL-5 and GM-CSF. In addition to the fact that IL-4 may be responsible for selective eosino phil transendothelial migration, IL-4 may exert an important modulator y mode of action on eosinophil migration and function within allergica lly inflamed tissue. Our findings suggest the presence of a functional IL-4R on eosinophils from atopic dermatitis patients.