Defensins in Plasma and in Bronchoalveolar Lavage Fluid from Patients with the Acute Respiratory Distress Syndrome

Abstract

: We measured the levels of defensins, antimicrobial peptides, and cytotoxic peptides in azurophil granules of neutrophils in plasma, and in bronchoalveolar lavage fluid (BALF) from patients with the acute respiratory distress syndrome (ARDS). High levels of plasma defensins were observed in samples from patients with ARDS. Samples of BALF from patients with ARDS also had more neutrophils and higher concentrations of defensins than did samples from healthy volunteers and from patients with idiopathic pulmonary fibrosis or diffuse panbronchiolitis. In addition, the concentration of interleukin (IL)-8 in BALF was higher in patients with ARDS than in other subjects. A significant correlation was found between the concentration of defensins and that of IL-8 in BALF from patients with ARDS. These findings suggest that the lung injury in ARDS is caused by defensins released by neutrophils that accumulate in the lungs.