SPP1 and COVID-19: The volcano plot illustrates a COVID-19-associated plasma protein profile composed of pro-inflammatory cytokines and chemokines (e.g., IL-6, CXCL10) in addition to growth factors (e.g., granulocyte–macrophage colony-stimulating factor (GM-CSF)) and endothelial factors (e.g., osteopontin (OPN), angiopoietin-2 (Ang-2)).