The serum eosinophil chemotactic factor (ECF) was evaluated by use of the modified Boyden chamber method. Flow cytometry (FCM) was applied to obtain highly purified eosinophils from peripheral blood of normal subjects. The maximal chemotaxis of these eosinophils was shown at 1×10(-7) M of platelet activating factor and leukotriene B4. In bronchial asthmatics with immediate asthmatic response (IAR), serum ECF activity showed only an early rise, and that in asthmatics with late asthmatic response (LAR) showed a precedent rise before bronchial reaction. Asthmatic patients with both IAR and LAR showed biphasic elevation in ECF activity. These findings suggest that the function of ECF in the pathogenesis of IAR is different from that in LAR. The eosinophils purified by FCM were very useful for measurement of ECF by the Boyden chamber method.
Eosinophil chemotactic factor (ECF)