More than 10% of serious COVID-19 infections produce antibodies that boycott the immune system

Thus, these autoantibodies would be able to boycott the functionality of the immune system in these patients. The find, led by the INSERM and the Rockefeller university (USA), has been possible thanks to the study of 987 blood samples, all of them from people who have been admitted for severe pneumonia caused by the new coronavirus in hospitals around the world.

The international team of researchers has compared the results of this study with the data of 663 asymptomatic people, none of whom had these autoantibodies, and of 1,127 healthy individuals, of whom only 4 did.

The discovery will help identify which people with SARS-CoV-2 infection are most likely to develop severe symptoms. It will also facilitate the adaptation of treatments for these people with autoimmunity.

The Spanish institutions that have participated are the Campus Can Ruti, with the Germans Trias i Pujol Hospital and IrsiCaixa –Centre promoted jointly by the "la Caixa" Foundation and the Department of Health of the Generalitat of Catalonia, together with the MútuaTerrassa University Hospital and the Dr. Negrín University Hospital of Gran Canaria.

"These antibodies are prior to infection, that is, people were already carriers and, as a consequence of this immune dysfunction, they will present more severe and potentially fatal manifestations of COVID-19. In other words, this alteration is the cause and not the consequence of the severity of the SARS-CoV-2 infection ", he explains David dalmau, from the MútuaTerrassa University Hospital.

More personalized treatments

Of the 10.2% found, the majority of cases described are men. "This trend could relate the production of autoantibodies against IFN, prior to infection, with sex," he says. Carlos Rodríguez-Gallego, of the University Hospital of Gran Canaria Dr. Negrín.

The clinical implications of the results of this study will be direct. First, detecting these antibodies will allow us to anticipate some of the patients who will end up developing severe symptoms. For this reason, and whenever they make a blood donation, it will be necessary to check for the presence of these autoantibodies.

Interferons are in our body's first line of defense when it comes to fighting SARS-CoV-2 infection. In some cases, they can even be given as a treatment for COVID-19.

However, in the case of patients with autoantibodies, treatment with interferon is not effective, since these antibodies precisely block interferon. These patients, however, may receive more personalized treatments, with the aim of eliminating autoantibodies.

The importance of interferon

In parallel, today the journal Science also publishes an international study by the same consortium of researchers where, in addition, they have also participated IDIBELL and the Vall d'Hebron University Hospital. The study shows that certain genetic alterations that affect the production of interferon would explain 3.5% of severe cases of COVID-19.

Thus, researchers have identified the importance of IFN in the fight against SARS-CoV-2 and can justify why 15% of infections end up triggering a serious clinical pathology.

When faced with a viral infection, some cells produce IFN, which acts as a warning signal from the immune system that, through a first emergency response, will block the viral infection.

After this blockage, a more sophisticated and specific response will be given to the immune system itself. "What aroused our curiosity were three patients with SARS-CoV-2 infection who developed severe pneumonia and who, due to a previous illness, we knew that they had antibodies that compromised their own immune system," they explain Javier Martínez-Picado, ICREA researcher at IrsiCaixa, David Dalmau and Carlos Rodríguez-Gallego.

"We thought, could it not be isolated cases and that this situation is the trigger for severe symptoms in more people? And that is why we began to analyze whether more patients had these autoantibodies," he adds Martinez-Picado.