Effect of drugs used in the treatment of asthma on the production of eosinophil-activating factor by monocytes.

The cytotoxic activity of eosinophils, as measured by their ability to kill antibody-coated schistosomula of Schistosoma mansoni, is enhanced by a factor (eosinophil-activating factor, EAF) which is secreted by peripheral blood monocytes from certain moderately eosinophilic individuals. The secretion of this factor by monocytes is inhibited by methylprednisolone (1 microgram/ml), beclomethasone (10 micrograms/ml) and theophylline (100 micrograms/ml), but not by sodium cromoglycate or salbutamol. Methylprednisolone, beclomethasone and theophylline do not inhibit either eosinophil cytotoxic activity or enhancement of eosinophil cytotoxic activity by EAF at these concentrations.