CCL2 and COVID-19: Elevated levels of cytokines in COVID-19 such as tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), IL-1β, granulocyte-macrophage colony-stimulating factor (GM-CSF), and chemokine (C-C-motif) ligand 2 (CCL2) that are primarily released by mast cells proved to be a substantial indication involving mast cell activation in COVID-19 patients [18].