Clinical and immunological features in children with multisystem inflammatory syndrome associated with SARS-CoV-2

BACKGROUND AND AIM OF THE RESEARCH: MIS-C is characterized by intense immune activation and increased production of cytokines. The aim of our study was to analyze the changes of cellular and humoral immune responses in children with MIS-C, depending on the severity of the disease. METHODS: Clinical, hematological and immunological parameters in children with severe and extremely severe MIS-C were compared. The study included a total of 50 patients divided into 3 groups: 20 children with extremely severe MIS-C requiring ICU care (MIS-C ICU “+”); 15 children with severe MIS-C but not requiring ICU care (MIS-C ICU “-”); and a control group of 15 children who had previously had COVID-19 and didn’t have MIS-C (MIS-C “-”). RESULTS: In patients with MIS-C requiring ICU care, heart and liver damage, hematological changes, and the development of severe complications such as edematous syndrome, polyserositis, DIC, and cardiogenic shock were statistically more common. Both groups of children with MIS-C had CD3+ T-cell lymphopenia and a decrease in CD95 expression. In the group of children with MIS-C requiring ICU care, a significant increase in the relative numbers of B-lymphocytes, CD3-HLA-DR+ and CD25 and a decrease of NK-cells was observed. CONCLUSIONS: Conditions requiring ICU care in children with MIS-C are associated with a more profound immune dysregulation, as evidenced by our data. (www.actabiomedica.it)