ENHANCEMENT OF HUMAN BASOPHIL HISTAMINE-RELEASE BY INTERLEUKIN-5

Substantial evidence indicates a close relationship between eosinophils and basophils. We examined whether interleukin 5 (IL-5), known to be eosinophilopoietic and capable ofselectively regulating eosinophil functions, has an affect on basophil functions. IL5 enhanced basophil histamine release evoked by anti-IgE, formyl-methionyl-leucyl-phenylalanine, or ionophore A23187 at picomolar concentrations. Direct action of IL-5 on human basophils was confirmed using highly purified basophil populations. These observations reveal the novel fact that IL5 is able to modulate basophil functions as well as eosinophil functions, and suggest that normal human basophils possess functional receptors for IL-5. © 1990, Rockefeller University Press., All rights reserved.