The potentially fatal condition known as a multisystemic inflammatory syndrome in children (MIS-C) is characterized by severe multisystemic inflammation and develops 2–5 weeks following exposure to the coronavirus 2 that causes severe acute respiratory syndrome. Since the early diagnosis of MIS-C is essential for prognosis, it was vital to develop clinical and laboratory indicators that indicate problems. In a group of 42 patients from Latin America, researchers described the immunological response, and clinical characteristics of those with acute MIS-C, and identified disease-related biomarkers.

Flow cytometry was used to characterize the immune system using peripheral mononuclear cells, and enzyme-linked immunospot, enzyme-linked immunosorbent assays, and neutralizing antibody assays were used to assess the humoral and cellular response to the severe acute respiratory syndrome coronavirus 2.

Strong T-cell activation and a cytokine storm were features of MIS-C. They found that individuals with shock had significantly raised levels of C-X-C motif chemokine ligand (CXCL) 9, IL-10, CXCL8, CXCL10, IL-6, and IL-18, whereas CCL5 was elevated in patients with milder symptoms. KD-like MIS-C was directly linked to monocyte dysregulation. It was interesting to note that MIS-C patients exhibited a deficiency in natural killer cell degranulation that continued to exist six months after the onset of the disease, suggesting it may contribute to disease vulnerability. Neopterin levels were found to be greater in their feces in most MIS-C, suggesting that this disease may have a biomarker for intestinal inflammation. Convalescent MIS-C patients showed severe acute respiratory syndrome coronavirus 2-specific cellular response and neutralizing antibodies, indicating maintained immunity.

The clinical characterization and thorough immunophenotyping of the Chilean MIS-C cohort offer important new perspectives on immunological dysregulation in MIS-C and help discover pertinent disease biomarkers may be utilized to gauge disease severity and organ involvement.