CSF3 and COVID-19: In COVID-19 patients, CSS is marked by significant increases in the plasma levels of pro-inflammatory cytokines including IL-6, IL-1β, IL-2, IL-8, IL-17, granulocyte colony-stimulating factor (G-CSF), granulocyte-macrophage colony-stimulating factor (GM-CSF), IP-10, monocyte chemoattractant protein (MCP)-1, macrophage inflammatory protein (MIP)-1α, and tumor necrosis factor (TNF)α, which leads to the recruitment of immune cells through a positive feedback loop that eventually forms a cytokine storm (7–9).