Abstract
BACKGROUND: Neutrophils are pivotal inflammatory cells in bronchiectasis pathophysiology, yet their stage-specific roles remain incompletely understood. This review synthesizes evidence on neutrophil activation across disease stages and explores therapeutic implications. METHODS: We performed a thorough literature review analyzing neutrophil behavior in bronchiectasis, focusing on proliferation, activation, and their contributions to tissue damage during the early and middle stages and analyzing their behavior and its correlation with disease progression. To ensure a comprehensive review of the literature on the role of neutrophils in bronchiectasis, we conducted a systematic search using the following databases: PubMed, Embase, and Web of Science. The search terms included 'neutrophils,' 'bronchiectasis,' 'neutrophil elastase,' 'bronchiectasis treatment,' and 'neutrophilic inflammation'. The search period covered articles published from January 2000 to June 2024. We also reviewed the reference lists of relevant articles to identify additional studies. RESULTS: Neutrophils demonstrated significant proliferation and activation during the early and middle stages of bronchiectasis, leading to the release of inflammatory mediators and an exacerbation of tissue damage. In particular, neutrophil activation during the middle stage of the disease was significantly positively correlated with the destruction of bronchial tissue. Furthermore, inhibiting neutrophil activation markedly reduced the release of inflammatory factors and improved the integrity of bronchial epithelial cells. CONCLUSIONS: This study highlights the role of neutrophil activation at different stages of bronchiectasis and suggests that targeting neutrophil activation may represent a promising therapeutic strategy.