Higher levels of granulocyte colony-stimulating factor (GCSF), interferon gamma-inducible protein 10kd (IP-10), monocyte chemotactic protein 1 (MCP-1), macrophage inflammatory protein 1A (MIP1A), TNF-α, IL-7, and IL-10 were also detected in the serum of patients with severe COVID-19 compared to patients with mild disease (Huang et al., 2020; Zhu et al., 2020; Yang et al., 2021). Here, CCL2 is linked to COVID-19.