DEL‐1, as an anti‐neutrophil transepithelial migration molecule, inhibits airway neutrophilic inflammation in asthma

Background Neutrophil migration into the airways is a key process in neutrophilic asthma. Developmental endothelial locus‐1 (DEL‐1), an extracellular matrix protein, is a neutrophil adhesion inhibitor that attenuates neutrophilic inflammation. Methods Levels of DEL‐1 were measured in exhaled breath condensate (EBC) and serum in asthma patients by ELISA. DEL‐1 modulation of neutrophil adhesion and transepithelial migration was examined in a co‐culture model in vitro. The effects of DEL‐1‐adenoviral vector‐mediated overexpression on ovalbumin/lipopolysaccharide (OVA/LPS)‐induced neutrophilic asthma were studied in mice in vivo. Results DEL‐1 was primarily expressed in human bronchial epithelial cells and was decreased in asthma patients. Serum DEL‐1 concentrations were reduced in patients with severe asthma compared with normal subjects (567.1 ± 75.3 vs. 276.8 ± 29.36 pg/mL, p