The effect of ketotifen on eosinophils as measured at LTC4 release and by chemotaxis

We examined the effect of ketotifen on calcium ionophore (A23187)-induced leukotriene C4 (LTC4) release from eosinophils, and platelet activating factor (PAF)-induced eosinophil chemotaxis to estimate the mechanism of the antiasthmatic property of ketotifen. Purified eosinophil suspensions were obtained from eight atopic asthmatic subjects and eight normals. Twenty microM of ketotifen significantly inhibited A23187-induced LTC4 release from eosinophils, and 10 microM of ketotifen significantly inhibited PAF-induced eosinophil chemotaxis. These findings may demonstrate the antiallergic pharmacological properties of ketotifen.