Biomarkers of Endothelial Damage in Distinct Phases of Multisystem Inflammatory Syndrome in Children

: Endothelial hyperinflammation and vasculitis are known hallmarks of acute COVID-19 and multisystem inflammatory syndrome in children (MIS-C). They are due to the direct effect of the virus on endothelial cells enhanced by pro-inflammatory modulators and may cause venous/arterial thrombosis. Therefore, it is essential to identify patients with endothelial damage early in order to establish specific therapies. We studied the monocyte chemoattractant protein 1 (MCP-1), the perinuclear anti-neutrophil cytoplasmic antibodies (pANCA), and the vascular endothelial growth factor A (VEGF-A) in serum from 45 MIS-C patients at hospital admission and 24 healthy controls (HC). For 13/45 MIS-C patients, we measured the three serum biomarkers also after one week from hospitalization. At admission, MIS-C patients had significantly higher levels of MCP-1 and VEGF-A than the HC, but no significant differences were observed for pANCA. While after one week, MCP-1 was significantly lower, pANCA was higher and VEGF-A levels were not significantly different from the admission values. These findings suggest an involvement of epithelium in MIS-C with an acute phase, showing high MCP-1 and VEGF-A, followed by an increase in pANCA that suggests a vasculitis development. The serum biomarker levels may help to drive personalized therapies in these phases with anticoagulant prophylaxis, immunomodulators, and/or anti-angiogenic drugs.