A rare, life-threatening hyperinflammatory syndrome that some children develop after coronavirus disease 2019 (COVID-19) is distinct from Kawasaki disease, according to a collaboration among European scientists.
Although most children with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection have mild or no symptoms, some develop a Kawasaki-like condition called multisystem inflammatory syndrome in children (MIS-C) about 4 to 6 weeks after their infection. To understand why, the investigators studied the immune responses of 41 children with mild COVID-19, 13 others who had MIS-C, and 28 children who were treated for Kawasaki disease before the pandemic.
They found that the MIS-C inflammatory response is distinct from the cytokine storm seen in adults with severe COVID-19 and from hyperinflammation in children with Kawasaki disease. Patients with MIS-C had less interleukin-17A–mediated inflammation and distinct autoantibodies compared with children who had Kawasaki disease. The results lay the groundwork for future studies on the mechanism of MIS-C.