CCL2 and COVID-19: The cytokine storm landscape of COVID-19 patients was further demonstrated in a retrospective study showing higher concentrations of IL-2, IL-7, IL-10, G-CSF, C-X-C motif chemokine ligand (CXCL)-10, C-C motif chemokine ligand (CCL)-2, CCL-3, and TNF-α in the plasma of severe COVID-19 patients (Huang et al., 2020; Lu et al., 2020).