New research published in Blood helped solve the mystery of longstanding estranged antigens and allowed scientists to describe the 44th blood group — the ‘Er’ system. It is a big step forward in providing the best care for every blood type.
It will also help prevent a mismatch that carries a risk of adverse immune responses, especially with transfusion patients and pregnant women with uncommon blood types.
The science and other stuff to know
Coating the surface of red blood cells, assorted antigens express a person’s blood type. Many are familiar with the more common ABO blood types; however, this is far from the only classification system.
Foreign substances trigger an immune response, producing antibodies to attack the specific unknown invaders. Therefore, it holds major clinical consequences for transfusions as different antigens from new blood can be seen as a threat. Additionally, due to their connected circulatory system, the mother’s blood could create antibodies against the fetus’ that cross through the placenta and cause harm to the unborn baby.
The researchers found Er4 and Er5 antigens with the help of samples from two women who lost their babies due to this tragic immune response. These two antigens are associated with the rupture of red blood cells of the fetus or newborn. Scientists also showed Piezo1, a well-studied protein, as the carrier molecule for the genetic mutation. Through gene-editing technology, the research team verified that a variation in Piezo1 caused blood incompatibility in the samples.
However, this new knowledge opens the landscape for life-saving treatments for pregnant mothers and their babies, such as a transfusion in the womb.
Scientists discovered the first Er antigen nearly 40 years ago, yet until now, the different mutations of Piezo1 were unknown. Now, five antigens are described.
Further understanding this rare blood can find a solution for mothers and their babies with incompatible types. It can also prevent Er blood transfusion patients from a complicated immune response. Through this knowledge, new tests can be developed to identify uncommon groups before it’s too late. Lab-grown blood is another possible avenue to produce a match to these rare blood types.
Though this is a new milestone, there are many other possible genetic mutations to unravel with further research on this rare blood type. New technology, such as DNA sequencing and gene-editing techniques, allows scientists to view known concepts from a different perspective.
Professor Ash Toye, Professor of Cell Biology at the University of Bristol and Director of the NIHR Blood and Transplant Research Unit, said in a press release: “This work demonstrates that even after all the research conducted to date, the simple red blood cell can still surprise us.”