CCL2 and COVID-19: The consistent reports of aberrant CD163hi and HLA-DRlo monocyte populations expressing the chemokine receptor CCR2 in the blood and hyperactivated airway monocytes and macrophages producing pro-inflammatory chemokines, including CCL2 and CCL3, were furthermore confirmed by high-dimensional phenotypic, transcriptomic, and functional profiling of immune cells from paired airway and blood samples obtained longitudinally from patients with severe COVID-19 (149).