Progress of studies on mechanism of eosinophils activation in airways

Abstract

Bronchial asthma is a chronic airway inflammation characterized with the eosinophils and mast cells infiltration in airway and airway hyperresponsiveness. Activated eosinophils play a key role in the initiation and development of asthma. Most of the eosinophils in the airway directly from peripheral blood, while a small portion are from primitive eosinophil progenitor cells. When the former ones are in peripheral blood the activation of esinophils begins under the interaction of endothelial cells. Then airway epithelial cells express cytokines such as IL-3, IL-6, IL-8, RANTES and eotaxin which is the important chemokine of eosinophils, recruiting eosinophils to the airways. Activation of the airway eosinophils of the above two sources are the result of the interaction of different inflammatory cells, cytokines and chemokines. For one thing, airway T cells, including Th2 and Thl cells, Th17 cells, mast cells, promote the activation of eosinophils through the release of different cytokines. And these cytokines such as IL-4,IL-5,IL-17 all activate eosinophils. On the other hand, various cytokines such as PAF, IL-33, IL-7 all involve in the activation of eosinophils and keep their viability. This article summarizes the scientific research of activate mechanism of eosinophils in the airways in recent years. Key words: Eosinophils; Bronchial asthma; Airway; Activation