Serologic and Cytokine Signatures in Children With Multisystem Inflammatory Syndrome and Coronavirus Disease 2019

Abstract Background The serologic and cytokine responses of children hospitalized with multisystem inflammatory syndrome (MIS-C) vs coronavirus disease 2019 (COVID-19) are poorly understood. Methods We performed a prospective, multicenter, cross-sectional study of hospitalized children who met the Centers for Disease Control and Prevention case definition for MIS-C (n = 118), acute COVID-19 (n = 88), or contemporaneous healthy controls (n = 24). We measured severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike receptor-binding domain (RBD) immunoglobulin G (IgG) titers and cytokine concentrations in patients and performed multivariable analysis to determine cytokine signatures associated with MIS-C. We also measured nucleocapsid IgG and convalescent RBD IgG in subsets of patients. Results Children with MIS-C had significantly higher SARS-CoV-2 RBD IgG than children with acute COVID-19 (median, 2783 vs 146; P