Given that MSCs exert various counteracting mechanisms, including the conversion of Th17 cells to anti-inflammatory FOXP3 T-regulatory cells and the promotion of inflammatory M1 macrophages to anti-inflammatory M2 macrophages against the pathological consequences associated with MIS-C, this therapy holds promise as an effective treatment for patients with MIS-C (41–44). Here, FOXP3 is linked to COVID-19–associated multisystem inflammatory syndrome in children.