Distinguishing immune activation and inflammatory signatures of multisystem inflammatory syndrome in children (MIS-C) versus hemophagocytic lymphohistiocytosis (HLH).

"Disclosure of potential conflict of interest: S. Chandrakasan serves on the advisory committee for SOBI. S. Prahalad serves on a macrophage activation syndrome adjudication committee for Novartis Pharmaceuticals and is an Op-Med fellow for Doximity for 2021-2022. E. J. Anderson has consulted for Pfizer, Sanofi-Pasteur, Janssen, and Medscape, and his institution receives funds to conduct clinical research unrelated to this manuscript from MedImmune, Regeneron, PaxVax, Pfizer, GlaxoSmithKline (GSK), Merck, Sanofi-Pasteur, Janssen, and Micron. He also serves on a safety monitoring board for Kentucky BioProcessing, Inc, and Sanofi-Pasteur. His institution has also received funding from the National Institutes of Health to conduct clinical trials of Moderna and Janssen coronavirus disease 2019 vaccines. C. A. Rostad’s institution has received funds to conduct clinical research unrelated to this manuscript from BioFire, Inc, GSK, MedImmune, Micron, Janssen, Merck, Moderna, Novavax, PaxVax, Pfizer, Regeneron, and Sanofi-Pasteur. The rest of the authors declare that they have no relevant conflicts of interest."

"This work was supported by the 10.13039/100000050National Heart, Lung, and Blood Institute (grant no. 1K08HL141635-01A1), Atlanta Pediatric Scholars Program K12 Scholar (grant nos. K12HD072245 and U54AI082973 to S.C.), and the National Institute of Allergy and Infectious Diseases 3U19AI110483-07S1 to I.S. (PI) and S.C. (Co-I) and S.P. (Co-I). S.P. is supported in part by the Marcus Foundation, Inc, Atlanta. Disclosure of potential conflict of interest: S. Chandrakasan serves on the advisory committee for SOBI. S. Prahalad serves on a macrophage activation syndrome adjudication committee for Novartis Pharmaceuticals and is an Op-Med fellow for Doximity for 2021-2022. E. J. Anderson has consulted for Pfizer, Sanofi-Pasteur, Janssen, and Medscape, and his institution receives funds to conduct clinical research unrelated to this manuscript from MedImmune, Regeneron, PaxVax, Pfizer, GlaxoSmithKline (GSK), Merck, Sanofi-Pasteur, Janssen, and Micron. He also serves on a safety monitoring board for Kentucky BioProcessing, Inc, and Sanofi-Pasteur. His institution has also received funding from the National Institutes of Health to conduct clinical trials of Moderna and Janssen coronavirus disease 2019 vaccines. C. A. Rostad’s institution has received funds to conduct clinical research unrelated to this manuscript from BioFire, Inc, GSK, MedImmune, Micron, Janssen, Merck, Moderna, Novavax, PaxVax, Pfizer, Regeneron, and Sanofi-Pasteur. The rest of the authors declare that they have no relevant conflicts of interest."