The effect of nedocromil sodium on human eosinophil activation.

Nedocromil sodium inhibited the increase in eosinophil activation (measured by IgG- and complement-dependent cytotoxicity assays) induced by platelet activating factor (PAF). Inhibition of the upregulation in eosinophil effector function by nedocromil sodium was dose-dependent (optimal at 10(-7) mol/L) and paralleled that produced by a specific PAF antagonist, BN 52021. In addition, preliminary data suggest that nedocromil sodium can inhibit the increase in IgG-dependent release of LTC4 from human eosinophils after stimulation with the synthetic tripeptide, formyl-methionyl-leucyl-phenylalanine (fMLP). These data support our previous hypothesis that part of the mode of action of nedocromil sodium may be due to its ability to directly block the chemotactic factor-induced enhancement of inflammatory cell activity.