CCL2 and viral infectious disease: Elevated levels of interleukin (IL)-1β, IL-6, IL-12, interferon-inducible protein-10 (IP-10), and monocyte chemotactic protein-1 (MCP-1) can be found in some COVID-19 patients, which may be due to the systemic inflammatory storm resulting from an overaggressive host immune response to viral infection [12].