CXCL9 and COVID-19: Some chemokines were also elevated in patients with severe COVID-19, as chemokine ligand (CCL)-2 (CCL2), CCL3, and chemokine CXC ligands (CXCL), CXCL8, CXCL9, CXCL10, and CXCL11 the most associated with this clinical condition (10, 11).