Overview
- The Mount Sinai-led study published in Cell on May 28 purified antibodies from 87 people with long COVID and transferred them into healthy mice, which then developed measurable physical and neurological changes.
- Those results establish that circulating autoantibodies can cause long COVID symptoms in a distinct subgroup rather than being only an associated finding.
- Researchers say the work provides a biomarker—detectable autoantibodies—to identify patients likely to respond to antibody-targeting therapies such as IVIG, FcRn inhibitors, plasmapheresis, or targeted cell therapies.
- Study authors warn the finding raises blood and plasma safety questions because the UK already excludes donors with long COVID while U.S. policy currently permits donation, and they call for urgent policy reassessment.
- Clinical validation is the next step: targeted trials and wider replication are needed before repurposed autoimmune treatments are adopted, but successful testing could more precisely relieve fatigue, brain fog and heart symptoms for many patients.