CCL2 and COVID-19: Several inflammatory cytokines and chemokines (interleukin (IL)-1β, IL-2, IL-6, IL-7, IL-8, IL-10, granulocyte colony-stimulating factor (G-CSF), granulocyte/macrophage colony-stimulating factor (GM-CSF), interferon gamma-induced protein (IP)-10, monocyte chemoattractant protein (MCP)-1, macrophage inflammatory protein (MIP)-1α, interferon (IFN)-γ, tumor necrosis factor (TNF)-α, C-C motif chemokine ligand (CCL)2 and CCL3) as well as C-reactive protein (CRP) are significantly upregulated in severe and critical COVID-19 patients (13, 14).