IN 2023, a paper was published in the journal Blood that ended a mystery stretching back four decades. It detailed the existence of , first proposed in the 1980s 鈥� and of which there are now 45 to date.
This particular discovery was born from tragedy. A baby died suddenly shortly after birth. Its mother was subsequently discovered to have a blood type (or group) that had never been identified before, whereas the baby had inherited its father鈥檚. The two blood groups interacted in a rare way that led to a fatal inflammatory response.
It reflects a long-standing mystery of the human body 鈥� just how many blood types there really are, and how this part of our physiology will evolve in the future. We are making headway: our recently improved understanding of the differences in our blood is helping to make transfusions safer and even starting to reveal how your blood group influences your health.
Advertisement
How many blood types are there?
Blood types are distinguished by what kind of antigens are attached to red blood cells and what kind of antibodies are in the surrounding plasma. The four most common blood groups are A, B, O and AB, which relate to combinations of antigens and antibodies, but delve a little deeper and there is astonishing complexity. Currently, the 45 blood types represent more than 390 different antigens and antibodies, with new discoveries being made all the time.
This variation is due to the ongoing battle that exists between humans and the pathogens around us, all of which would like to latch on to our red blood cells and invade our bodies. In particular, the Plasmodium parasites responsible for malaria are thought to have driven many of these differences. at NHS Blood and Transplant, which looks after blood donation services in England, highlights the Duffy antigen, which can be used as an entry point by Plasmodium parasites, meaning that humans who have evolved with a are relatively resistant to malaria. ,鈥� says Thornton.
Does your blood type affect your personality?
Other links between blood type and health have been reported 鈥� as have more spurious claims that your blood group also influences your personality and behaviour. There is bad news on the latter 鈥� contrary to what you might have heard, your blood type doesn鈥檛 , nor is there good evidence that it is . Claims that you should are also unproven.
However, there are several studies that suggest people without an O-group blood type are at a 12 per cent increased risk of heart disease, possibly due to factors affecting blood clotting. People with blood group A are thought to be , possibly because the Heliobacter pylori bacteria that drive the disease are more capable of latching onto the stomach lining. Likewise, people with blood group O appear to be . Other links will no doubt be discovered in time.
With the decreasing cost of genetic analysis, it will soon be possible for everyone to have their blood group profiled and stored on their mobile phone, predicts at New York Blood Center. 鈥淚t鈥檚 the next frontier for blood transfusion,鈥� she says. 鈥淭here鈥檚 11 or 12 different antigens which are the most likely to cause a negative outcome with a transfusion, so people will be able to be precisely matched for those.鈥� But it will inevitably be an ongoing race to perfect this knowledge. 鈥淲e鈥檙e always going to discover new blood groups because humans evolve, and we change,鈥� says Thornton. 鈥淎s a species, being different and having diversity is absolutely key to our survival.鈥�
