The role of neutrophils in asthma

Bronchial asthma is a chronic respiratory disease，characterized by airway inflammation，airway hyperresponsiveness，reversible airway obstruction and airway remodeling，in which a variety of cells including airway inflammatory cells and structural cells are involved. Previous studies have shown that asthma is mainly driven by Th2 cytokines IL-4，IL-5，and IL-13，leading to airway eosinophil inflammation. With further research，however，it has been found that neutrophils are also closely related to asthma. Numbers of neutrophils are elevated in airway through increased chemotaxis and decreased apoptosis，which is earlier than eosinophils，leading to airway neutrophilic inflammation. Neutrophils can produce elastase，myeloperoxidase，neutrophil extra- cellular traps，chemokines and cytokines，participating in the occurrence and development of asthma. The antagonists against these molecules，such as anti-IL-8 receptor antibody，anti-IL-17 antibody，and DNase，have shown positive effects on neutrophilic asthma，but further studies are needed to support their clinical application. This article mainly reviews the role of neutrophils in asthma and related mechanisms.