How strong is blood type AB

Covid-19: Severe course influenced by blood group?

Why do some people show only mild symptoms when infected with SARS-CoV-2, while others become seriously ill and have to be ventilated? In addition to age, previous illnesses, smoking and an overreacting immune system, another factor could be decisive - the blood group. This is what scientists from the University Medical Center Schleswig-Holstein (UKSH) and the Christian-Albrechts-Universität zu Kiel (CAU) found out in collaboration with a working group from Norway. In the world's first large-scale genome-wide association study, they found certain gene variants that could influence the course of Covid 19 disease.

The lead for the BMBF-funded project COVID19HOSTaGE lies with Professor Dr. Andre Franke, the director of the Institute for Clinical Molecular Biology at Kiel University. The research team he leads examined 5,000 blood samples from northern Italy and Spain, which are among the regions in Europe most affected by the corona pandemic. In the interview, Professor Franke goes into the first findings of the study.

Professor Franke, what did you find out from your study?

Among other things, we examined variants of the genes that determine the blood group. We were able to detect a connection between the course of Covid-19 and blood groups 0 and A. Significantly more Covid 19 patients had blood group A compared to the normal population - about 5 to 10 percent more, depending on the region. Conversely, significantly fewer patients had blood group 0, i.e. this blood group offers 50 percent more protection against serious Covid 19 disease.

What data are your investigations based on and how do you go about doing it?

Our hypothesis was that an infection with SARS-CoV-2 and a severe course of the disease can be influenced by genetic factors. This hypothesis was based on the results of so-called genome-wide association studies for infectious diseases such as influenza. However, our results surprised us: Neither in the chromosome segment 6p21 we suspected, which is associated with the immune system and many infectious diseases, nor in the gene IFITM3, which is associated with influenza, we were able to find significant differences between the healthy test subjects Study and find the examined samples from patients. The section we examined on chromosome 3, on the other hand, had not yet been associated with Covid-19.

Genome-wide Association Studies (GWAS)

Genome-wide association studies (GWAS) look for risk factors for diseases at the level of the genetic material DNA (genome). In such studies, the researchers look for typical changes in the entire genome and see whether these changes occur more frequently in people with certain diseases. That doesn't have to mean that the changes are causally related to the disease. But they are associated with the disease, so they are related to it in a known or unknown way.

Are there other genetic signatures that enable a prediction of the course of a Covid 19 disease?

The next few weeks will show that. Our study was just the beginning and could clearly describe two chromosomal segments. Further analyzes are now following in international consortia such as the “Covid19 host genetics initiative” (covid19hg), an international platform through which researchers exchange their data in order to accelerate genetic research into SARS-CoV-2. We will also review our analysis with more patient and control samples from Italy and Spain.

How can your work help to find effective therapeutic approaches?

Our work is primarily of a basic scientific nature and is carried out in addition to vaccine research aimed at prophylaxis. We ran another small piece of the puzzle to better understand the origins and course of Covid-19. This could help to develop active ingredients for new targets, i.e. to identify biomolecules to which an active ingredient can bind. Previous studies have shown that drugs that bind to targets identified through genetic association studies are twice as likely to help patients.

Preliminary findings from your study were first published on a so-called preprint server in order to make them available to the research community as quickly as possible.

Our work is now in New England Journal of Medicine been published. There the work was temporarily listed on the front page. We are very proud and happy about this success. The speed with which we conducted this study and excellent international teamwork certainly contributed to this.

What's next now?

We ourselves will primarily take a closer look at possible connections between other blood group characteristics and the severity of the course of the disease and, if necessary, carry out another genome-wide association study with samples.

At the beginning of the SARS-CoV-2 pandemic, the Federal Ministry of Education and Research opened the rapid response module of the “Guideline for the Funding of a National Research Network for Zoonotic Infectious Diseases” for a call for funding for research into Covid-19. From March 3, 2020, researchers were able to submit applications to contribute to the understanding of the virus and its spread and to develop therapeutic and diagnostic approaches against Covid-19.

Back to the project overview for the research of Covid-19