Blood clots continue to wreak havoc in patients with severe COVID-19 infections, and a new study explains what may be causing them in half of the patients.
The culprit: An autoimmune antibody is circulating in the bloodstream, attacking cells and causing blood clots in arteries, veins, and microvascular. Blood clots can cause life-threatening events like a stroke. And, in COVID-19, microscopic blood clots can restrict blood flow in the lungs, impairing oxygen exchange.
In addition to new coronavirus infection, these coagulation antibodies are often seen in patients with autoimmune disease antiphospholipid syndrome. Co-author Yogen Kanthi, MD, an assistant professor at the Frankel Medical Center of Michigan and a Lasker Investigator at the National Institute of Heart, Lung and Blood Institute of the National Institutes of Health, said the link between autoantibodies and COVID-19 are not expected.
“In patients with COVID-19, we continue to see a constant, self-amplifying, cycle of inflammation and coagulation in the body,” says Kanthi. “Now we know that autoantibodies could be the culprits in this cycle of coagulation and inflammation, making already struggling people even sicker.”
‘Some of the worst blood clots we’ve ever seen’
Co-author Jason Knight, MD, Ph.D., a rheumatologist at Michigan Medicine, has been studying antiphospholipid syndrome antibodies in the general population for many years.
“Half of all patients hospitalized with COVID-19 are positive for at least one of the autoantibodies,” said Knight, associate professor of medicine and leading expert on autoantibody-induced diseases.
In the new Medical translation science published, they found that about half of all patients with severe illness with COVID-19 were exhibiting a high-level combination of both dangerous antibodies and superactivated neutrophils. , cause the white blood cells to explode. In April, the team was the first to report that patients hospitalized for severe COVID-19 had a higher level of neutrophil trapping in their blood.
To find out more, they studied the burst neutrophils and COVID-19 antibodies together in mouse models to see if this could be the dangerous combination behind blood clots.
“Antibodies from active COVID-19 infected patients have produced a significant amount of blood clotting in animals – one of the worst clotting phenomena we’ve ever seen,” Kanthi said. “We have discovered a new mechanism by which patients with COVID-19 can form blood clots.”
Attacks COVID-19 clot from any angle
These findings are not yet ready for clinical practice, the researchers say, but they add a new perspective to the study of powerful inflammation and thrombosis in COVID-19 patients.
Kanthi, Knight, first author Yu (Ray) Zuo, MD, and colleagues now want to know whether patients with severe illness with this high amount of antibodies will have better results if antibodies are blocked or eliminated. revoke.
If so, that could warrant an aggressive treatment like plasmapheresis, which is often used in severe autoimmune diseases, Zuo explained. It involves IV blood drawing, filtering and its replacement with fresh plasma that does not contain antibodies associated with blood clots.
“We know people with the highest levels of autoantibodies have worse in terms of lung function and inflammatory antibodies,” said Zuo, associate professor of medicine and rheumatologist at Michigan Medicine. healthy cells.
“We don’t yet know what triggers the body to produce these antibodies, so the next step will be additional research to identify the antibodies that trigger and target,” said Knight. .
In addition, these findings raise new questions around the use of nursing plasma as a viable COVID-19 treatment, but the team says more research is needed to look at termites. take care of this.
“We are currently investigating how long these antibodies remain in circulation after recovery from the new coronavirus,” said Knight.
Researchers are also currently running a randomized clinical trial called DICER, which is testing a well-known anticoagulant, dipyridamole, in patients with COVID-19 to determine if it is effective. than placebo in reducing too many blood clots or not.
“Dipyridamole is a safe, inexpensive and extensible old medicine,” Kanthi said. “The FDA approved it 20 years ago to prevent blood clots, but we recently discovered its ability to block specific inflammation from COVID.”
Higher NET levels in the blood are associated with more severe COVID-19
Autoantibodies promoting coagulation that may explain coagulation have been observed in some patients with severe cases of COVID-19, Medical translation science (Year 2020). stm.sciencemag.org/lookup/doi/… scitranslmed.abd3876
Provided by University of Michigan
Quote: New cause of COVID-19 clot identified (2020, November 2) retrieved November 2, 2020 from https://medicalxpress.com/news/2020-11-covid-blood -clots.html
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