CCL2 and COVID-19: The observation that pro-inflammatory cytokines and chemokines, including Interleukin-6 (IL-6), Interferon-γ (IFNγ), Monocyte Chemoattractant Protein-1 (MCP-1), and Interferon gamma-induced protein 10 (IP-10), are massively produced in severe COVID-19 indicate the presence of a T helper 1 (TH1) cell-polarized response, resulting in the homing of monocytes and T lymphocytes, but not neutrophils, into infected sites [5].