CCL21 and acute respiratory distress syndrome: C-C motif ligand 21 (6Ckine), lipopolysaccharide receptor (CD14), interleukin-1 receptor 4 (IL-1 R4/ST2), insulin-like growth factor binding protein 2 (IGFBP-2), insulin-like growth factor I (IGF-I), and defensin-beta1 (BD-1) were significantly changed in SP patients, as compared with healthy controls or SP-ARDS patients at corresponding days.