CCL2 and COVID-19: COVID-19 in the severe phase presents a cytokine storm with increased plasma concentrations of tumor necrosis factor (TNF)-α, IL-1β, IL-2, IL-6, IL-7, IL-8, IL-10, IL-17, chemokine ligand 2 (CCL2), chemokine C-C motif ligand 3 (CCL3), granulocyte colony-stimulating factor (G-CSF), interferon (IFN)γ, and IFNγ-inducible protein 10 (55, 56).