HGF and COVID-19: Next, we identified a core group of four cytokines released by activated monocytes and neutrophils, [transforming growth factor–α (TGF-α), hepatocyte growth factor (HGF), oncostatin M (OSM), and S100 calcium binding protein A12 (S100A12/EN-RAGE)], which were enriched in patients with severe or EOD COVID-19 and grouped them into a myeloid activation module.