CD163 and COVID-19–associated multisystem inflammatory syndrome in children: The biomarker form of this protein is the soluble CD163 (sCD163) found in plasma and produced from increased sCD163 shedding mediated by TNF-α.32 Increased abundance of sCD163 and marked elevation of macrophage activity have been recognized as markers in several inflammatory diseases.33 Mostafa and colleagues34 reported increased levels of sCD163 in children with SAR-CoV-2 infection and MIS-C, compared with HC, which likely reflects the exaggerated proinflammatory host response and suggests a potential therapeutic role for sCD163 antagonists.