Blood clots in people with severe COVID-19 may be related to abnormal
antibody response

Date:
July 28, 2021
Source:
University of Reading
Summary:
A new study of cells shows that antibodies produced by the body in
response to COVID-19 may be triggering a blood clotting response
in patients with severe disease.



FULL STORY ========================================================================== Inflammation and blood clotting seen in very severe cases of Covid-19
may be caused by the antibodies sent to fight the disease activating unnecessary platelet activity in the lungs.


==========================================================================
A new paper published in the journal Bloodreveals how antibodies produced
by our bodies to protect against Covid-19 are triggering increased
function of platelets, which may be causing fatal blood clots in patients
with severe disease. Platelets are small cells found in blood which form
clots to stop or prevent bleeding, but where platelets don't function
properly this can lead to serious health concerns such as strokes and
heart attacks.

The study took antibodies produced to fight the coronavirus's spike
protein, from people with severe Covid-19 infections, and cloned them
in a lab to study.

The team found that the small sugars found on the surface of these
antibodies were different to antibodies from healthy individuals, and
when those cloned antibodies were introduced in a lab to blood cells taken
from healthy donors, there was an observed increase in platelet activity.

The study team also found that it was possible to reduce or stop
platelets from responding in this way in the laboratory by treating
blood with active ingredients from different medication which is known
to either inhibit platelet function or immune responses. The findings
suggest that it may be possible for drugs that are currently used to
treat immune system problems to reduce or stop the cells from producing
an exaggerated platelet response.

A trial led by Imperial College London and Imperial College Healthcare
NHS Trust -- called MATIS -- is already testing these drugs in clinical
trials with patients at hospital sites across the UK to see whether they
will reduce serious clotting for hospitalised Covid-19 patients.

The lab-based study of human cells provides key evidence to support the scientific basis for the MATIS trial and, while there are yet to be any
results reported from this clinical trial, the two teams will continue
to work closely together as the clinical trial develops.

Professor Jon Gibbins, Director of the Institute for Cardiovascular
and Metabolic Research at the University of Reading said: "Until now,
we have only had assumptions about why platelets involved in clotting
were being activated during Covid-19 infection.

"One way to think of what is happens is that the immune response that is designed to protect you from the infection in some cases, particularly
in severely ill patients, actually causes more damage. In this case,
the antibodies that are produced to stop Covid-19 from spreading trigger infected cells to induce platelet activity which causes clotting even
though there is no wound that needs healing.

"We are particularly excited because our studies of platelets in the
laboratory establishes important mechanisms that explain how and why
dangerous blood clots may occur in severely ill Covid-19 patients,
and importantly, also provides clues as to how this may be prevented." Co-author Nichola Cooper, reader at Imperial College London and consultant haematologist at Imperial College Healthcare NHS Trust, who also designed
and leads the MATIS trial said: "Early on in the Covid-19 pandemic it was
clear that the infection was causing an overwhelming immune response,
including blood clotting, and that many of the more severe cases and
deaths were related to this.

"Having been involved in early research around blood clotting related to inflammation, it occurred to me that the drugs we already use for other disorders could be easily accessible treatments for Covid-19. We are
yet to see results from the MATIS trial so we do not yet know how these
drugs will work in patients, but our hope is that we can both inhibit
the inflammatory response and prevent severe disease and blood clots. It
is exciting to see our collaboration with Reading backing our theory
already and providing a solid scientific basis for clinical trials." ========================================================================== Story Source: Materials provided by University_of_Reading. Note: Content
may be edited for style and length.


========================================================================== Journal Reference:
1. Alexander P Bye, Willianne Hoepel, Joanne L Mitchell, Sophie
Me'lanie
Je'gouic, Silvia Loureiro, Tanya Sage, Gestur Vidarsson, Jan
Nouta, Manfred Wuhrer, Steven W. de Taeye, Marit van Gils,
Neline Kriek, Nichola Cooper, Ian Jones, Jeroen den Dunnen,
Jonathan M Gibbins. Aberrant glycosylation of anti-SARS-CoV-2
IgG is a pro-thrombotic stimulus for platelets. Blood, 2021; DOI:
10.1182/blood.2021011871 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2021/07/210727212832.htm

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