unborn baby Having trouble. Doctors at the mother’s hospital in the UK knew there was a problem with the fetus’ blood, so they decided to perform an emergency C-section a few weeks before the baby was due. But despite this, and the subsequent blood transfusion, the baby suffered a brain hemorrhage with devastating consequences. It unfortunately passed away.
It is unclear why the bleeding occurred. But there was a clue in the mother’s blood that doctors noticed some strange antibodies. Some time later, as medical staff tried to learn more about them, the mother’s blood samples were sent to a laboratory in Bristol, run by researchers who study blood types.
They made a startling discovery: The woman’s blood was of an extremely rare type, which may have made her baby’s blood incompatible with her own. This may have prompted her immune system to produce antibodies against the baby’s blood — antibodies that then crossed the placenta and harmed her baby, eventually leading to its loss. It may seem unbelievable for something like this to happen, but decades ago, before doctors had a better understanding of blood types, it was much more common.
By studying blood samples from the mother and a few others, scientists were able to pinpoint exactly what made her blood different, and in the process identified a new set of blood types – the “Er” system, to be described soon 44th.
You are probably familiar with the four main blood types – A, B, O, and AB. But this is not the only blood classification system. There are many ways to group red blood cells based on differences in the sugars or proteins (called antigens) that coat the surface of the red blood cells. The grouping systems operate simultaneously, so your blood can be classified into each system – for example, it might be type O in the ABO system, positive (instead of negative) in the rhesus system, etc.
Because of differences in antigens, for example, if someone receives incompatible blood from a donor, the recipient’s immune system may detect and respond to these antigens as foreign. This can be very dangerous, which is why if someone is being transfused, the donated blood needs to be a suitable match.
Over the past decade, researchers have described a new blood classification system every year on average. These newer systems often involve extremely rare blood types, but for those who have been exposed to them, just knowing they have one can save lives. It’s the story of how scientists solved the latest blood system mystery and why it’s so important.
Back in 1982, researchers first described an unusual antibody in a blood sample, suggesting that the mysterious blood type was out there. Scientists could only go so far, but they knew that an antibody is a clue to some unknown molecule or structure that prompts a person’s immune system to produce it.
In the years that followed, many more people with these unusual antibodies appeared — but only occasionally. Typically, these individuals surfaced through blood tests containing mysterious and rare antibodies. Ultimately, Nicole Thornton and her colleagues at NHS Blood and Transplant in the UK decided to investigate what was behind the antibodies. “We deal with rare cases,” she said. “It starts with a patient having a problem we’re trying to solve.”
