Researchers at Michigan Medicine studied blood samples from 172 hospitalized COVID-19 patients in search of eight types of clot-causing autoimmune antibodies. Autoimmune disease refers to when the immune system attacks healthy cells by mistake, per Johns Hopkins Medicine. Findings were published Monday in Science Translational Medicine.
“In patients with COVID-19, we continue to see a relentless, self-amplifying cycle of inflammation and clotting in the body,” Dr. Yogen Kanthi, co-corresponding author and assistant professor at the Michigan Medicine Frankel Cardiovascular Center and a Lasker investigator at the National Institutes of Health’s National Heart, Lung, and Blood Institute, said in a news release. “Now we’re learning that autoantibodies could be a culprit in this loop of clotting and inflammation that makes people who were already struggling even sicker.”
These autoantibodies were said to circulate through the blood, attack cells and cause clotting in the veins, arteries and microscopic vessels, per the news release. Blood clots can lead to strokes, and earlier in the pandemic reports arose of younger coronavirus patients with blood clots experiencing sudden strokes.
The autoantibodies in the study are usually found in patients with a so-called antiphospholipid syndrome, which is an autoimmune disease, per the news release.
Dr. Jason Knight, corresponding author and rheumatologist at Michigan Medicine said “half of the patients hospitalized with COVID-19 were positive for at least one of the autoantibodies, which was quite a surprise.”
The study also said, of the 172 patients, 19% died and 8% were still hospitalized during the analysis. In addition to the clot-causing autoantibodies, researchers found that many patients in the study had “neutrophil extracellular traps (NETs) in their blood,” or “destructive, exploding white blood cells,” contributing to inflammation, per the release.
“These findings suggest that half of patients hospitalized with COVID-19 become at least transiently positive for …[the] antibodies and that these autoantibodies are potentially pathogenic [or cause disease],” study authors concluded.