Blood clots continue to wreak havoc in critically ill patients COVID-19 and a new study explains what might be causing them in half of the patients.
The culprit: an autoimmune antibody circulating in the bloodstream, attacking cells and causing blood clots in arteries, veins, and microvascular. Blood clots can cause life-threatening events such as strokes. 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 commonly 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 continued to see a constant, self-amplifying, cycle of inflammation and coagulation in the body,” Kanthi said. “Now we know that autoantibodies could be the culprits behind the clotting cycle and inflammation that makes 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 specialist in autoantibodies.
In the new Medical translation science published, they found that about half of patients who were critically ill with COVID-19 exhibited a combination of high levels of both dangerous antibodies and destructive, hyperactive neutrophils, cause an explosion of white blood cells. 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 blast neutrophils and COVID-19 antibodies together on mouse models to see if this could be the dangerous combination behind blood clots.
“Antibodies from active COVID-19 infected patients 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 drawing blood through an IV, filtering it, and replacing it with plasma does not contain antibodies related to blood clots.
“We know people with the highest levels of autoantibodies have deteriorated in lung function and inflammatory antibodies, even in people,” 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 whether it is present. more 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 the ability to stop this particular type of inflammation from COVID.”
References: “Prothrombotic autoantibodies in the serum of hospitalized patients with COVID-19” by Yu Zuo, Shanea K. Estes, Ramadan A. Ali, Alex A. Gandhi, Srilakshmi Yalavarthi, Hui Shi, Gautam Sule, Kelsey Gockman, Jacqueline A. Madison, Melanie Zuo, Vinita Yadav, Jintao Wang, Wrenn Woodard, Sean P. Lezak, Njira L. Lugogo, Stephanie A. Smith, James H. Morrissey, Yogendra Kanthi and Jason S. Knight, May 2 11 years 2020, Medical translation science.
DOI: 10.1126 / scitranslmed.abd3876