CCL2 and acute respiratory distress syndrome: Strictly replicated proteins in all five studies identified several inflammatory mediators associated with death in ARDS patients, including previously identified markers (IL1RN, IL6, IL18, IL18R1, IFNγ, and CXCL10) as well as several novel markers (CCL2, CCL7, CCL8, CCL20, CXCL11, AREG, IL1RL1, FLT1 and IL24).