CXCL1 and COVID-19: Another finding reported is that men severely affected by COVID-19 expressed at least 12 pro-inflammatory cytokines, such as IL-4, IL-8, chemokine 1 ligand (CXCL1), soluble CD4 ligand (sCD4L), macrophage inflammatory protein (MIP-1β), and monocyte chemoattractant protein-1 (MCP-1), which were not found in women with this phenotype [67].