Antiphospholipid Autoantibodies May Lead to Blood Clots After COVID-19 Infection
February 23, 2022
Last week, the NIH released a media advisory discussing a recent study on rogue antibodies. These rogue antibodies, identified as circulating antiphospholipid autoantibodies, are thought to be involved in severe blood clotting following a COVID-19 infection.
Antiphospholipid autoantibodies can be present in multiple autoimmune diseases, including rheumatoid arthritis, lupus, ANCA vasculitis, and antiphospholipid syndrome, and can activate other immune responses. Click here for a study on COVID-19 vaccines in patients with antiphospholipid antibodies, as well as another study testing the safety and tolerability of mRNA vaccines in those with antiphospholipid antibodies.
Scientists in the study compared blood samples from COVID-19 patients to healthy controls. They found that the “presence of circulating antiphospholipid antibodies was a strong marker of the ability of COVID-19 serum to activate endothelium,” meaning these autoantibodies may cause cells to lose their ability to resist clotting. Endothelium is a thin membrane that lines the inside of blood vessels, controlling enzymes which regulate blood clotting amongst other functions.
Additionally, when researchers removed the these autoantibodies from COVID-19 blood samples and added them to healthy control samples, they witnessed an inflammatory response within the blood vessels. When the antiphospholipid autoantibodies were removed from the COVID-19 blood samples, endothelial cell indicators for clotting fell. This finding shows that higher levels of antiphospholipid autoantibodies can be associated with severe disease outcomes for COVID-19 patients.