CXCL9 and COVID-19: Of note, it was observed that the reduced production of IFN-β in patients with COVID-19 is accompanied by elevated secretion of interleukin (IL)-6, chemokine (C-C motif) ligand 2 (CCL2), CCL5, CCL8, chemokine (C-X-C motif) ligand 8 (CXCL8), CXCL9, CXCL16, and CXCL2, which contribute to aggravating COVID-19 pathology [7,8] through the recruitment of inflammatory monocytes and neutrophils into the respiratory tract [6].