Macrophage-derived chemokines, such as monocyte chemoattractant protein-1 (MCP-1/CCL2), macrophage inflammatory protein-2 (MIP-2/CXCL2), and regulated upon activation, normal T cell expressed and secreted (RANTES/CCL5), play indispensable roles in the recruitment and migration of immune cells to the site of inflammation in ALI [54,56,63,65]. This evidence concerns the gene CCL2 and acute respiratory distress syndrome.