Induction of the Neutrophil Migration in Normal Subjects due to Asthmatic Bronchoalveolar Lavage Fluid (BALF)

Human neutrophils play an essential role in the innate immune response and are involved in the pathogenesis of the severe and corticosteroid-resistant asthma. Asthma is characterized by an infiltration of inflammatory cells into the lung and by a cytokine release. The aim of this study is to investigate the effects of a bronchoalveolar lavage fluid (BALF) on the chemotaxis and apoptosis of neutrophils which were isolated from healthy subjects. The BALF of subjects with asthma induces the blood neutrophil chemotaxis in the opposite of that in normal subjects. The IL-8, IL-6, and monocyte chemoattractant protein-1 (MCP-1) levels in BALF were higher in subjects with asthma than in normal subjects. The BALF of normal and asthmatic subjects has no effect on neutrophil apoptosis of BALF. MCP-1 delays the constitutive apoptosis of normal blood neutrophils, but has no effect in normal BALF neutrophils. These results may indicate that inflammatory factors secreted by the lung tissue of patients with asthma trigger the neutrophil chemotaxis and also induce the neutrophil dysregulation.