Multisystem Inflammatory Syndrome in Children (MIS-C) described
Researchers from SciLifeLab, Karolinska Institutet and the Tor Vergata University in Italy, have mapped the immune response in children affected by the rare and life-threatening Multisystem Inflammatory Syndrome (MIS-C), an inflammatory syndrome associated with COVID-19.The results, published in the scientific journal Cell, shows that the inflammatory response in MIS-C differs from both Kawasaki, a severe inflammatory condition that mainly affects children under the age of five, and severe acute COVID-19.
During the ongoing COVID-19 pandemic, young children seem to be relatively unaffected by SARS-CoV-2 infection with only a few rare exceptions. Researchers have now discovered a new, autoimmune life-threatening hyperinflammatory syndrome named Multisystem Inflammatory Syndrome in Children (MIS-C), associated with COVID-19.
The syndrome strongly resembles Kawasaki disease but most of the affected children are older than five (Kawasaki disease mainly affects children under the age of five) and they typically exhibit more severe symptoms. The disease generally presents itself 4-6 weeks after infection with high fever, organ dysfunction, and strongly elevated markers of inflammation. It attacks healthy tissue in the heart and blood vessels, among others.
In a new collaborative study, led by SciLifeLab researcher Petter Brodin (Karolinska Institutet), researchers have managed to reveal the immunological aspects of this mysterious and rare disease. After comparing blood samples from 13 children with MIS-C, treated at Karolinska University Hospital in Stockholm and Bambino Gesù Children’s Hospital in Rome, with samples from 28 Kawasaki disease patients collected from 2017 to 2018, prior to the COVID-19 pandemic. Samples from children with mild COVID-19 were also included.
“Our results show that MIS-C is truly a distinct inflammatory condition from Kawasaki disease, despite having some shared features,” says Petter Brodin, in a press release from Karolinska Institutet. “The hyperinflammation and cytokine storm detected in children with MIS-C is also different from that seen in adult patients with severe, acute COVID-19, which we recently described in another publication.”
When comparing the samples, the researchers observed different frequencies of specific immune cell populations, inflammatory cytokines and chemokines in the blood. The children with MIS-C were lacking IgG-antibodies to common cold coronaviruses, which the other patients did not. Several autoantibodies that could be responsible for the pathogenesis of MIS-C were also found. Looking forward, the researchers are now trying to identify genetic risk factors for developing the disease after being infected with SARS-CoV-2.
“There is an urgent need to better understand why a small minority of children infected with SARS-CoV-2 develop MIS-C, and we are adding a piece to the puzzle”. “Better knowledge of the pathogenesis is important for development of optimal treatments that can dampen the cytokine storm and hopefully save lives, as well as for vaccine development to avoid MIS-C caused by vaccination”, says Petter Brodin.
