CXCL8 and acute respiratory distress syndrome: Protein biomarkers from immune cells, including IL-8, IL-6, IL-1β, IL-18, GM-CSF (CSF2), G-CSF (CSF3), sTNFR1 (TNFRSR1A), IL-10, and TNF (TNF), have been studies in ARDS; however, it is difficult to distinguish which cell types are responsible for these biomarkers.