Intravenous immune globulin (IVIG)—a common treatment for multisystem inflammatory syndrome in children (MIS-C)—likely works by depleting immune cells called neutrophils, according to a recent study funded by the National Institutes of Health (NIH). MIS-C is a rare condition that usually affects school-age children who initially had only mild COVID-19 symptoms or no symptoms at all. The researchers also found that IVIG works in a similar manner for treating Kawasaki disease, another rare inflammatory condition that affects children and shares symptoms with MIS-C. The findings are published in the Journal of Clinical Investigation.