COVID-19: Disease with many faces
In March last year, the World Health Organization (WHO) declared the COVID-19 outbreak a pandemic. So far, more than 95 million people worldwide have been infected with the SARS-CoV-2 coronavirus, and over two million people have died. New knowledge about the dangerous pathogen is still being gained. Researchers now report that the disease comprises at least five different variants.
Over 95 million people worldwide have already contracted the corona virus (as of January 18, 2021). Some of those infected develop serious illnesses, but many have no or only mild symptoms. Researchers now report that there are at least five different variants of COVID-19.
How the immune system reacts to the infection
Like the German Center for Neurodegenerative Diseases eV (DZNE) in one Message writes, the COVID-19 disease caused by the SARS-CoV-2 coronavirus comprises at least five different variants according to current studies, which differ in how the immune system reacts to the infection.
Researchers from the DZNE and the University of Bonn present these findings together with other experts from Germany, Greece and the Netherlands in the renowned science journal “Genome Medicine“. The study results could help treat the disease more effectively.
From symptomless to life-threatening
An infection with the SARS-CoV-2 coronavirus can have different effects: Many infected people seem not to notice the virus attack at all. In other cases, the effects can range from flu-like symptoms and neurological disorders to severe and even life-threatening pneumonia.
“The division of COVID-19 into mild and severe courses falls short. The disease is much more diverse and, of course, you want a therapy that is tailor-made for each person affected. What helps one may be ineffective for another, ”explains Dr. Anna Aschenbrenner, a scientist at the LIMES Institute of the University of Bonn, who also belongs to the DZNE’s systems medicine department.
“In this respect, it makes sense to want to understand what these differences are based on. If you can fix it to scientific criteria and assign those affected accordingly, this increases the chances of effective treatment, ”explains Aschenbrenner, who is a member of the“ ImmunoSensation ”cluster of excellence at the University of Bonn.
“That’s why we looked at the immune system. Because many studies meanwhile indicate that his reaction to the infection with SARS-CoV-2 plays a decisive role in the course of COVID-19. “
Against this background, a research team around Anna Aschenbrenner, together with colleagues from Germany and abroad, analyzed the blood of people with and without COVID-19. These samples came from a total of 95 people from Bonn, Athens (Greece) and Nijmegen (Netherlands).
According to the information, the so-called transcriptome of the immune cells in the blood was determined for each patient and enormous amounts of data were evaluated using bioinformatics methods. Using the molecular fingerprint generated in this way, the scientists were able to identify which genes were switched on and off within the immune cells.
Such signatures of gene activity – also called “expression patterns” – provide information about the condition of cells and thus also about their properties and functions, which can change depending on the situation.
Interestingly, the blood count obtained in this way was largely determined by the “neutrophil” family: They are the most common of the so-called white blood cells and are at the forefront of the immune response chain and are mobilized very early to ward off infections. The cells influence the production of antibodies and also other cells that contribute to immunity.
Greatly changed gene structure
“First of all, it must be noted that the expression patterns of immune cells in people with COVID-19 differ fundamentally from those in healthy people. The gene activity that we can read out in the blood is greatly changed. But there are also striking differences among patients. On this basis we have identified five different groups. We’re talking about molecular phenotypes, ”says Dr. Thomas Ulas, expert in bioinformatics at the DZNE.
“Two of them stand for serious disease courses. The other three show more moderate symptoms. ”According to the communication, the classification was based solely on the transcriptome data. Only in retrospect was it checked which clinical courses the individual phenotypes corresponded to.
Comparison with other diseases
The researchers used their findings to compare COVID-19 with other diseases and also with data from healthy people. For this purpose, the experts were able to draw on data from the “Rhineland Study” – a population study by the DZNE in the Bonn area – as well as scientific databases.
A wide range of diseases was taken into account for the comparison: including viral infections such as influenza (flu), infections with HIV and Zika, bacterial infections such as tuberculosis and bacterial sepsis, and inflammatory diseases such as rheumatoid arthritis.
“All five COVID-19 phenotypes differ from the other diseases that we examined,” says Ulas. “COVID-19 apparently has a unique biology, which is reflected in the gene activity of immune cells in the blood. In this respect, expression analysis could be used to diagnose COVID-19. That would be an alternative or a supplement to current procedures. “
Drug candidates identified for therapy
The researchers also looked for possible drugs against COVID-19. To do this, the scientists used the effects of around 900 approved drugs on the expression patterns of cells, which are stored in databases.
“We calculated which pharmaceuticals could counteract the changed gene activity profiles of the individual COVID-19 phenotypes,” Aschenbrenner explains the procedure in one Message. On this basis, drug candidates for treatment could be identified.
“In April last year, for example, we calculated a potential effectiveness for dexamethasone and baricitinib in one of the patient groups we identified with a severe course. It has to be clearly stated that these types of analyzes are not recommendations for treatment, ”says the researcher.
“However, they do offer starting points for therapy development, which must then be checked in appropriate studies. In the case of dexamethasone and baricitinib, our predictions turned out to be correct. This is an indication of the strength of our approach of using blood transcriptomes to better characterize and classify patients. “(Ad)
Author and source information
This text corresponds to the requirements of the medical literature, medical guidelines and current studies and has been checked by medical professionals.
This article is for general guidance only and should not be used for self-diagnosis or self-treatment. He can not substitute a visit at the doctor.