Rogue antibodies make cells 'sticky' to trigger blood clots in COVID-19 patients
Finding brings researchers closer to finding the exact cause of
inflammation and clotting in severe COVID-19 patients

Date:
February 17, 2022
Source:
Michigan Medicine - University of Michigan
Summary:
Scientists have discovered that 'rogue' antibodies found circulating
in the blood of COVID-19 patients have the potential to cause
endothelial cells to lose their resistance to clotting. These
antiphospholipid autoantibodies can trigger blood clots in the
arteries and veins of patients with autoimmune disorders, including
lupus and antiphospholipid syndrome. The findings provide an even
stronger connection between autoantibody formation and clotting
in COVID-19.



FULL STORY ========================================================================== Scientists have discovered that "rogue" antibodies found circulating in
the blood of COVID-19 patients have the potential to cause cells to lose
their resistance to clotting.


========================================================================== Researchers at Michigan Medicine and the National Heart, Lung, and Blood Institute studied the blood samples of nearly 250 patients hospitalized
for COVID-19. They found higher-than-expected levels of antiphospholipid autoantibodies, which can trigger blood clots in the arteries and veins of patients with autoimmune disorders, including lupus and antiphospholipid syndrome.

Antibodies typically help the body neutralize infections. Autoantibodies
are antibodies produced by the immune system that mistakenly target and sometimes damage the body's own systems and organs.

In a 2020 study, the research group found that autoantibodies from
patients with active COVID-19 infections caused "a striking amount of
clotting" in mice.

In the new study they uncover the possible reason: the autoantibodies
appear to stress the endothelial cells that make up the inner lining of
blood vessels and, in doing so, cause the cells to lose their ability to prevent blood clots from forming. The results are published in Arthritis
& Rheumatology.

"This provides an even stronger connection between autoantibody
formation and clotting in COVID-19," said Hui Shi, M.D., Ph.D., lead
author of the paper and rheumatology research fellow at Michigan
Medicine. "When endothelial cells are activated, they cause healthy
blood vessels to become 'sticky,' attracting other cells to the vessel
walls and becoming more prone to thrombosis. This can affect many of
the body's essential organs." The researchers found that when they
removed the antiphospholipid autoantibodies from COVID-19 blood samples,
the endothelial cell activation that promotes clotting was lost. While
the link is strong, future studies must be done to find whether these autoantibodies are the precise cause of thrombosis that contributes to
clotting and increased severity of COVID-19, says Jason Knight, M.D.,
Ph.D., co-author of the study and associate professor of rheumatology
at Michigan Medicine.

"We must do more research to decide if it is beneficial to screen patients
with severe COVID-19 for these autoantibodies to evaluate their risk of clotting and progressive respiratory failure," Knight said. "Eventually,
we may be able to repurpose treatments used in traditional cases of antiphospholipid syndrome for COVID-19. This is a further step towards
a full understanding of the interplay between coronavirus infection, the
human immune system and vascular health." Additional authors include Yu
(Ray) Zuo, M.D., Sherwin Navaz, B.S., Alyssa Harbaugh, B.S., Claire Hoy,
B.S., Alex Gandhi, M.S., Gautam Sule, Ph.D., Srilakshmi Yalavarthi, M.S., Kelsey Gockman, Jacqueline Madison, M.D., Melanie Zuo, M.D., Michael
Maile, M.D., all of Michigan Medicine, as well as Jinato Wang, NHLBI,
Yue Shi, Shanghai University of Sport, Yogendra Kanthi, M.D., NHLBI This
work was supported by a grant from the Rheumatology Research Foundation.

========================================================================== Story Source: Materials provided by
Michigan_Medicine_-_University_of_Michigan. Original written by Noah
Fromson. Note: Content may be edited for style and length.


========================================================================== Journal Reference:
1. Hui Shi, Yu Zuo, Sherwin Navaz, Alyssa Harbaugh, Claire K. Hoy,
Alex A.

Gandhi, Gautam Sule, Srilakshmi Yalavarthi, Kelsey Gockman,
Jacqueline A.

Madison, Jintao Wang, Melanie Zuo, Yue Shi, Michael D. Maile,
Jason S.

Knight, Yogendra Kanthi. Endothelial cell‐activating
antibodies in COVID‐19. Arthritis & Rheumatology, 2022;
DOI: 10.1002/art.42094 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2022/02/220217131916.htm

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