Unlike earlier studies, scientists have found that severe COVID-19 does not solely bring about a hyperactive immune system, but instead the body's defense response is captured in a constant loop of activation and inhibition, an advance that may help develop superior therapeutics to combat the deadly illness.

The researchers, such as those from the Center for Neurodegenerative Diseases (DZNE), assessed blood samples by a total of 53 men and women with COVID-19 from Berlin and Bonn in Germany, whose path of disease was abbreviated as moderate or severe based on the World Health Organization (WHO) classification.

In the study, published in the journal Cell, they assessed the gene activity and the amount of proteins on the level of human immune cells circulating in the bloodstream of the patients using very large resolution single-cell OMICs technologies.

"By implementing bioinformatics methods on this exceptionally detailed data collection of this gene activity of every individual cell, we can obtain a comprehensive insight of the continuing processes in the white blood cells," explained Yang Li, a co-author of the study by the Centre for Individualised Infection Medicine (CiiM) in Germany.

"In combination with the observation of important proteins on the surface of immune cellswe were able to decode the changes in the immune system of patients using COVID-19," additional Birgit Sawitzki, yet another co-author of this study.

The scientists found that in severe cases of COVID-19 the immune cells known as neutrophils and monocytes in these patients are only partially activated and they do not function properly.

However, these immune cells were found to be ready to defend the patient against COVID-19 in the case of mild disease classes, explained Antoine-Emmanuel Saliba, yet another co-author of the analysis.

"They can also be programmed to trigger the remaining immune system. This ultimately contributes to an effective immune response against the virus," Saliba said.

But in acute COVID-19 cases, the scientists noticed that there are considerably more immature neutrophils and monocytes that have a"rather synergistic effect on the immune reaction"

This phenomenon, according to the scientists, may also be observed in other severe ailments, even though the reason for this is uncertain.

"Many indications indicate that the immune system stands in its own way during acute courses of COVID-19," said research co-author Leif Erik Sander.

"This could possibly cause an inadequate immune response against the coronavirus, with a simultaneous severe inflammation in the lung tissue," Sander added.

According to the researchers, the current findings could lead to new therapeutic choices.

"Our data suggest that in severe instances of COVID-19, plans should be considered go beyond the treatment of other viral diseases," said research co-author Anna Aschenbrenner from the University of Bonn in Germany.

In the case of viral infections, suppressing the immune system might not be beneficial, according to the scientists.

"If, but there are a lot of dysfunctional immune cells, as our study shows, then one would very much like to suppress or reprogram cells that are such " Jacob Nattermann, another co-author of this study by the University Hospital Bonn.

"Drugs that act on the immune system might have the ability to help. However, this can be a delicate balancing act. After all, it is not an issue of shutting down the immune system completely, but only those cells which slow themselves down, so to speak," Nattermann explained.

He added that scientists could have a page from cancer research in attempting to understand ways to take care of these immature cells.