Ordinarily your blood type It makes little difference in your daily life, except if you need a blood transfusion.
But why we have blood types and what they are for is still unknown, and very little is known about their links to viruses and diseases. Unlocking the role that blood types play could help scientists better understand the risk of disease for people in different blood groups.
“I think it’s fascinating, evolutionary history, although I don’t think we have the answer as to why we have different blood types,” said Laure Segurel, a human evolutionary geneticist and researcher at the National Museum of Natural History in France. .
Why do they matter
What he didn’t know is that humans should only get blood from other humans.
This is why: Your ABO blood group is identified by antibodies, part of the body’s natural defense system, and antigens, a combination of sugars and proteins that line the surface of red blood cells. Antibodies recognize foreign antigens and tell your immune system to destroy them. That is why giving blood to someone from the wrong group can be deadly.
For example, I have type A + blood. If a doctor accidentally injected me with type B, my antibodies would reject it and work to break down foreign blood. As a result, my blood would clot, interrupt my circulation, cause bleeding and breathing difficulties, and potentially die. But if I received type A or type O blood, it would be fine.
Your blood type is also determined by Rh status, an inherited protein found on the surface of red blood cells. If you have it, you are positive. If you don’t, you are negative.
Most people are Rh positive, and those people can obtain blood from negative or positive blood type matches. But people with Rh negative blood should generally only get Rh negative red blood cells (because their own antibodies can react with blood cells from incompatible donors).
That leaves us with eight possible primary blood types, although there are some rarer ones.
Evolutionary puzzle
“Many species of primates … also have the differences of being A, being B, being AB,” said Segurel. “Whether it’s a great ape or a new world monkey, it’s quite intriguing that differences have been found or maintained in so many different species.”
Blood types are unlikely to have lasted that long by chance. They must give us some kind of evolutionary advantage, Segurel said.
The ABO blood type gene not only influences our blood; It is also active in a wider variety of tissues and organs, including our digestive or respiratory systems, Segurel explained. This can be important when our bodies face infections with different blood types that offer us protection against different pathogens and diseases.
“The evolutionary interest in maintaining these (blood) types may not be related to their function in the blood but to their function in the respiratory or digestive tissues,” he said. “They are the two places where you have the most contact with viruses and bacteria: the places where you inhale air and digestive tissue.”
“If you imagine a cocktail of pathogens … there could be a cycle where sometimes B is advantageous, sometimes it is A. Going through those different preferences and you will end up with a population with different blood types.”
While we don’t know precisely how, Segurel said that variation in the blood type gene influences our susceptibility to different diseases. What we do know is that certain blood groups are more vulnerable to certain diseases.
So what about the coronavirus?
A handful of studies have shown a link between blood type and the new coronavirus, although most involved a small number of people and some were not peer-reviewed.
A team of European researchers who published their findings in the New England Journal of Medicine in June found that people with type A blood had a 45% higher risk of infection than people with other blood types, and people with type O blood. they were only 65% as likely to become infected as people with other blood types. They studied more than 1,900 severely ill coronavirus patients in Spain and Italy, and compared them to 2,300 people who were not sick.
He said it could also be explained by the probability that the virus carries the antigen from the infected person’s blood group. As such, antibodies produced by a person with blood group O can neutralize the virus when caught by a person with blood group A, similar to the rules for blood transfusions.
“However, this protective mechanism would not work in all situations. A person from blood group O could infect another person from blood group O, for example,” he explained, adding that any protective effect is unlikely to be large and that the amounts of antibodies are highly variable from person to person.
People with type A should not be alarmed, nor should people with type O relax, said Sakthivel Vaiyapuri, an associate professor of cardiovascular and poison pharmacology at the University of Reading. in the United Kingdom.
Vaiyapuri, in collaboration with Thi-Qar University in Iraq, is conducting a study on the role of blood types based on data from more than 4,000 people in Iraq who had Covid-19 and 4,000 who did not get sick. He said that the first results suggest that type O could have a protective effect, but it is not definitive. And given the number of underlying variables that exist, any effect, protective or not, is likely to be quite small.
“Group O should not think that they are not going to get this disease. They should not be running everywhere and not maintain social distance, nor should group A panic,” he said.
Blood type research has sometimes fallen between different academic disciplines, but a better understanding of why we have different blood groups and the relationship between blood type antibodies and disease risk will likely help us develop vaccines and design new drugs. , even for Covid- 19)
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