The cell stimulation assay also showed the lack of upregulation of cytokine production (IFNγ, IL1β, IL6, IL10, IP10, TNFα, GM-CSF) in acute MIS-C, SBI, and SVI following mitogen stimulation, which was restored in convalescence. Here, CXCL10 is linked to COVID-19–associated multisystem inflammatory syndrome in children.