IL6 and COVID-19–associated multisystem inflammatory syndrome in children: Both CRS and MIS-C are characterized by high IL-6 and IL-10 serum concentrations, which serve as diagnostic criteria.15 In addition, constitutive pSTAT3 expression has been found in individual CRS patients.15 Aberrantly strong immune responses in patients with a high SARS-CoV-2 burden in combination with an initially inhibited IFNγ response were described as potential triggers of COVID-19-associated inflammatory syndromes.16 The clinical relevance of these findings has now been confirmed by treatment trials for CRS/MIS-C targeting the IL-6 receptor (tocilizumab).