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A dangerous antibody found in the blood of people with severe COVID-19

This calls into question the safety of the treatment of coronavirus infection with a blood transfusion of ill patients.

July 14th. One of the antibodies that appears in the blood of people who have had a severe form of coronavirus infection does not suppress the virus, but causes powerful inflammation. This conclusion was reached by Dutch biologists. The possible consequences of this problem and how to deal with it, scientists described in an article for the bioRxiv electronic scientific library .


“We found that antibodies from the blood plasma of heavy carriers of COVID-19, which can bind to the new-type spike-like protein of coronavirus, when interacting with macrophage cells, cause a very powerful inflammatory response. This explains why at the moment it“ turns on ” adaptive immunity, the health status of many patients is deteriorating sharply, "the researchers write.

According to current data, due to infection with a new type of coronavirus (SARS-CoV-2), the immunity of patients is disrupted, mass inflammations, microthrombi and other problems appear that threaten the patient’s life not only with COVID-19, but also by themselves. Now scientists are trying to understand why they arise and how to prevent them from appearing.

Trojan antibodies

The Dutch molecular biologists, led by the professor at the University of Amsterdam, Menno de Winter, found out the possible cause of this phenomenon. In addition, scientists discovered the first hints that plasma transfusions from people who had been ill with COVID-19 could be dangerous for new patients.

Researchers studied antibodies present in the blood of such patients. They were interested in how these molecules affect the behavior and functioning of other components of the immune system. To do this, scientists extracted several dozens of different antibodies from plasma samples and added them to the medium with immune cells from the lungs and other human organs.

Due to these antibodies and viral particle analogs, a strange and dangerous effect on human health was manifested. In the presence of “dummies” of coronavirus, these antibodies bind to certain types of macrophages, immunity “cleaner” cells, and cause them to produce a huge number of signaling molecules, which cause inflammation.

Something similar happened when scientists simply added SARS-CoV-2 analogues to the blood samples of seriously ill patients. This suggests that antibodies directly affect the behavior of immune cells. Interestingly, only antibodies that could bind to a spike-like protein (also called spike protein or S-protein), the part of the coronavirus membrane that is responsible for penetrating new cells, caused a similar effect.

As subsequent experiments showed, the disturbances in the macrophages that cause these antibodies not only accelerated the development of inflammation, but also contributed to the formation of trobms and disrupted the functioning of the vessel walls. Both of these problems, coupled with inflammatory reactions, are today considered one of the main causes of complications with COVID-19.

Researchers say they suppressed all of these reactions with substance R406, one of the components of fostamatinib, a cure for immunogenic thrombocytopenia. This compound blocks the activity of immune cell enzymes that are responsible for the production of pro-inflammatory signaling molecules in macrophages.

“All this not only suggests that drugs like R406 can be used to treat COVID-19, but it also points to a new source of danger associated with the use of patients' plasma in the treatment of coronavirus infection. In particular, doctors should think about that we need to remove such antibodies from the serum of donors who have suffered a severe form of the disease, "the scientists concluded.

It should be added that the article was not reviewed by independent experts and the editors of scientific journals did not read, as is usually the case in such cases. Therefore, conclusions from it and similar articles should be treated with caution.

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