HMGB1 and macrophage activation syndrome: For instance, robust inflammatory response to MIS-C with elevated IL-1β, IFN-α, GM-CSF, and HMGB1 levels explained the severity and outcome of the clinical syndrome in both MIS-C and COVID-19 disease [26], while the serum concentrations of IL-18 were correlated with creatinine, liver enzymes, and troponin, which reflected disease severity in COVID-19 disease with macrophage activation syndrome [27].