While fewer cases of severe Coronavirus Disease 2019 (COVID-19) are reported globally in children, a small proportion of SARS-CoV-2 infected children develop a novel pediatric febrile entity called multisystem inflammatory syndrome in children (MIS-C) that develops 2 to 5 weeks after initial SARS-CoV-2 exposure. MIS-C primarily effects male children and children of Hispanic or black descent. MIS-C manifests as a severe and uncontrolled inflammatory response with multiorgan involvement. A hyperinflammatory state is evidenced by clinical makers of inflammation including high levels of C-reactive protein (CRP), ferritin, and D-dimers, and an increased expression of pro-inflammatory cytokines. Children often present with persistent fever, severe gastrointestinal symptoms, cardiovascular manifestations, respiratory symptoms and neurological symptoms6-11,13. Cardiovascular manifestations include hypotension, shock, cardiac dysfunction, myocarditis and pericardial effusion. In the united states, admission to the intensive care unit occurs in approximately 58% of cases. To understand disease pathogenesis of MIS-C and proteins associated with the severe form of disease we performed proteomics analysis of serum or plasma samples. We collected serum from healthy children (SARS-CoV-2 negative, n=20), mild MIS-C (non-ICU, n=5) and severe MIS-C (ICU, n = 20) patients. MIS-C definition and diagnosis was performed according to CDC guidelines. Healthy adult serum (n = 4) was also used for reference ranges quality control and we obtained plasma samples from Kawasaki Disease (KD; n=7) patients that were recruited before the Coronavirus Disease 2019 (COVID-19) pandemic.