As the Federal Center for Health Education (BZgA) wrote on its portal “infektionsschutz.de” already months ago, several studies indicate that the blood group can influence both the personal risk of an infection and the severity of the disease signs with COVID-19. However, these scientific studies have not shown consistent results. Researchers from Austria now report new findings on this.
The individual risk of coronavirus infection can vary considerably. But why do some people actually contract the novel pathogen – and others do not? The blood group could play a role here, as researchers now report.
Scientists at the Medical University (Med Uni) Graz are currently investigating the possible correlation between different blood groups and the probability of a COVID-19 infection at the University Clinic for Blood Group Serology and Transfusion Medicine. According to a press release, initial research results confirm comparable studies from China and Europe, according to which people with blood group 0 are less likely to contract COVID-19 than people with blood groups A, B or AB. Now the mechanism underlying this observation is to be investigated.
Research is currently underway worldwide to find the causes that promote infection with SARS-CoV-2 or influence the course of COVID-19. The blood group AB0 seems to play a role here, as study results from China and some European countries show. Red blood cells (erythrocytes) are ring-shaped cells that carry oxygen and carbon dioxide through the bloodstream. As explained in the communication, the “envelope” of the red blood cells is called “membrane”. This membrane contains several different carbohydrates (sugars) and proteins, which give the red blood cells a certain surface structure, they are also called “antigens”.
Comparable studies confirm
Also the “blood group carbohydrates” A and B are such antigens. For the AB0 blood group one distinguishes the properties A, B, AB and 0 (zero). According to experts, people with blood group “0” have none of these mentioned blood group antigens on the surface of their red blood cells. In people with blood group “AB”, both carbohydrates (A and B) are contained in the erythrocyte membrane. And for blood group “A” only the antigen “A” is present, for blood group “B” only the antigen “B”.
In the first research results presented, it has already been shown that a correlation between blood group and an infection with the coronavirus SARS-CoV-2 can be detected. Thus early indications of a study from China as well as a genome-wide association study (European GWAS COVID-19 research group) can be confirmed. The study at the Medical University of Graz is designed as a retrospective case-control study with a total of 399 SARS-CoV-2 positive tested persons, who were in hospital treatment due to COVID-19 disease.
It is known that the sugar structures, as they are pronounced in the AB0 blood group system on the cell surface of the red blood cells, but also in tissues of the respiratory organs and the gastrointestinal tract, play a role not only in the blood group recognition of antibodies, but also in the recognition of microorganisms. “Pathogens, such as bacteria or viruses, can selectively bind to blood group structures and influence the colonization of the affected tissue or its uptake into the cells,” explains the study leaders Eva Maria Matzhold, molecular biologist at the University Clinic for Blood Group Serology and Transfusion Medicine, Med University Graz. “In our study, we are investigating whether ABO blood group characteristics can represent a possible further risk factor for infection and COVID-19 disease”, adds transfusion physician Thomas Wagner.
“Our study results show that people with blood group O have a statistically significant lower probability of contracting COVID-19 than people with other ABO phenotypes (blood group A, B or AB),” the researchers report. In contrast, blood group AB was found significantly more often in infected patients and patients with COVID-19 compared to the frequency of occurrence in the healthy control group.
Blood group and corona disease risk
However, the severity of COVID-19 disease remains unaffected by AB0 blood group. This means that the disease does not progress more easily in people with blood group 0 than in people with blood group AB. Therefore, AB0 blood grouping should not be used as a prognostic marker for the course of COVID-19. According to the researchers, the mechanism that plays a role in this process must now be thoroughly investigated. Other blood group systems will also be included in the investigations, the scientists explain. (ad)
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