CXCL9 and COVID-19: To investigate the role of cytokines and chemokines in the inflammatory status of COVID-19 and MIS-C, we measured plasma levels of IL-1ß, IL-2, IL-4, IL-5, IL-6, IL-10, TNF-α, IL-17A, IFN-α, IFN-γ, CXCL10/IP-10, CXCL8/IL-8, CXCL9/MIG, CCL5/RANTES, and CCL2/MCP1.