If the AWO and the Resus systems are the most famous and Bristol University has discovered a new blood group system called Er, which is now the 44th blood group system.
Unfortunately, the unfortunate circumstances led to this discovery: the unborn child had signs of distress, so the medical team of the British hospital to which the mother had been admitted decided to conduct an emergency caesarean section before the deadline; unfortunately, the child died of brain haemorrhage despite the team ' s efforts and blood transfusions; in an investigation into the cause of death, the doctors realized that the mother ' s blood contained strange antibodies; her blood sample was sent to the Bristol lab.
Researchers found that blood was extremely rare, potentially incompatible with the child's blood, so the mother's immune system could produce antibodies against the blood of her child, who unfortunately crossed the placental barrier, a rare disease called the hemolic disease of a newborn, which is defined as the destruction of a child's erythrocytes by mother's antibodies, and the woman's blood was different from the blood of her child by a special protein present on the surface of her erythrocytes.
Two rare forms causing serious illness
The antigens that distinguish erythrocytes are absolutely decisive in blood transfusion: if the blood is incompatible with the blood of the recipient, his or her immune system will immediately view these antigens as alien to the body and attack them; for this reason, some specialist researchers are now carefully examining every blood sample that has been found to be "unnormal", and over the past decade, a dozen new blood group systems have been discovered.
Nearly 40 years ago, a new highly infectious antigen called Era was discovered, but the molecular basis of this antigen, as well as two other members of the Er blood group collection that was later discovered, has not yet been clarified.
Not only were researchers able to characterize the genetic background of these three antigens, but they also identified two new antigens from the same "family" called Er4 and Er5 that are very rare, so these five antigens make it possible to create a completely new blood group system. "," says Nicole Thornton from NHSBT's International Blood Reference Laboratory.
Recently discovered blood groups, Er4 and Er5, are rare but unfortunately cause of hemolytic neonatal disease, and two patients whose cases have been examined have lost their children for this reason.
The team identified the Piezo1 protein, which plays an important role in many biological processes, such as the blood group carrier of this system. The mutations in the PIEZO1 gene encoding this protein are the source of various ER antigens. "," reported researchers in the magazine Blood.
These genetic variations replace certain amino acids that make up Piezo1 proteins in a small number of people. As a result, blood cells containing the most common Piezo1 protein are considered to be alien to the immune system. There are currently five possible variations of Piezo1 protein on the surface of the erythrocyte, which may lead to incompatibility.
But it is possible that other genetic mutations associated with this rare blood have yet to be detected. The American team from the New York blood center is also interested in the blood group Er and has additional blood samples that appear to have been obtained from people with a rare group of Er. Research by the British team may soon produce other variations.
At the same time, the discovery will allow for the development of new tests to identify people with unusual blood groups in order to provide the best medical care, and will also enable early detection and treatment of problems of incompatibility between pregnant women and their children.
The results of this study are likely to be used to formally define a new blood group determination system later this year at a meeting of the International Society for Blood Transfusion.