Effect of neutrophil-derived eosinophil chemotactic factor (ECF) in human and guinea pig skin

The in vivo effectiveness of eosinophil chemotactic factor (ECF), secreted in vitro by human neutrophils (PMN) during phagocytosis, is tested in 2 model systems. Injection of ECF into guinea pig ears causes a preferential attraction of eosinophils with time that is more marked in animals with preexisting eosinophilia. In the same model system, activated serum attracts fewer eosinophils and more PMN. In human skin windows, ECF and activated serum are equally effective on a quantitative basis, but ECF is more selective for eosinophils in patients with eosinophilia. With normal controls, ECF and activated serum attract PMN equally well. The studies confirm previous in vitro observations on the properties of ECF and suggest a potentially significant role of this factor during pathological processes.