CCL2 and COVID-19: COVID-19 patients have high levels of proinflammatory cytokines, including interleukin (IL)-1β, IL-6, IL-8, interferon-gamma (IFNγ), 10 kD interferon-gamma-inducible protein (IP-10), and monocyte chemoattractant protein-1 (MCP-1, CCL-2), which probably activate T-helper-1 (Th1) cell responses [4].