Evaluation of bronchoalveolar lavage fluid from ARDS patients with regard to apoptosis

Summary Background Apoptosis is thought to play an important role in the development of acute respiratory distress syndrome (ARDS). We evaluated the bronchoalveolar lavage (BAL) fluid from ARDS patients focusing on apoptosis. Methods The study enrolled 31 ARDS patients and 20 healthy controls. BAL fluid levels of caspase-cleaved cytokeratin-18 (CK-18) and soluble mediators such as interleukin-8 (IL-8), soluble Fas (sFas), soluble Fas ligand (sFasL), growth-related oncogene-α (GRO-α), granulocyte colony-stimulating factor (G-CSF), and tumour necrosis factor-related apoptosis-inducing ligand (TRAIL) were measured using enzyme-linked immunosorbent assay (ELISA). Results The BAL fluid caspase-cleaved CK-18 levels in ARDS patients were higher than those in controls, reflecting increased epithelial apoptosis, and were correlated with lung injury scores ( rs =0.49). The BAL fluid levels of all mediators were significantly higher in ARDS patients than in controls. In ARDS patients, the BAL fluid IL-8 level was positively correlated with the levels of sFas ( rs =0.57), GRO-α ( rs =0.47), and TRAIL ( rs =0.45). The BAL fluid IL-8 ( rs =0.61), sFas ( rs =0.57), G-CSF ( rs =0.44), and TRAIL ( rs =0.33) levels were correlated with the BAL fluid neutrophil count. The G-CSF levels were significantly higher in non-surviving than in surviving ARDS patients [median 183.4 pg/mL (interquartile range 76.7–315.9) vs. 63.8 pg/mL (36.2–137.2); p