New research in Nature suggests that an autoimmune over-reaction could be what’s driving a pattern of multisystem inflammatory syndrome in children (MIS-C) after COVID-19 illness. Researchers looked at 199 blood samples from children with MIS-C and 45 control samples from children with COVID-19 but without MIS-C. About one-third of the MIS-C patients had autoantibodies for part of the human protein SNX8, which is found in the heart, lungs, kidneys, brain, skin, eyes, and gastrointestinal tract. The antibodies that fought SARS-CoV-2 appeared to also attack the MIS-C patients’ own body tissues.
Locating the threat: According to a press release from the University of California – San Francisco announcing the research findings, killer T cells “were involved in this case of mistaken molecular identity.” The authors believe that MIS-C—which is still quite rare—may be the result of multiple uncommon events converging and that this research could lead to new ways to investigate other autoimmune diseases as well.