It is extremely rare.
A, B, AB, O … These blood groups are known to everyone, but there are many others. On the surface of red blood cells, there are many markers called antigens. For example, in the ABO system, group A people have antigen A, those in group B The antigen B, AB people have both, and people O have none of them. In total, more than 360 antigens have been listed in the various blood group systems. And the latest, 47ᵉ, was recently discovered by English researchers, after more than 50 years of research.
In 1972, researchers had spotted a particular antigen, called Anwj, present on the surface of the red blood cells of almost the entire population. But a handful of people around the world were devoid of it. Thanks to a technique called “genetic sequencing”, researchers from the NHS Blood and Transplant, in Bristol (England), identified the manager: a very small protein. In 99.9 % of people, this protein is well present and transports the ANWJ antigen. But in some people, a rare mutation in the gene of this protein completely prevents its manufacture. Result: they become anwj-negatives.
To prove their observations, scientists artificially injected the gene of this protein who is ill in cells that were devoid of it, and the latter began to express the ANWJ antigen. This demonstration explained in the journal “Blood” made it possible to officially classify a new blood group system, called Mal, Because it is the protein that determines belonging to this blood group. “Douc’an is a very small protein with interesting properties, which makes it difficult to identify and has forced us to conduct several research to bring together the necessary evidence for the establishment of this blood group system”said Dr. Tim Satchwell, one of the authors of the study.
Receiving incompatible blood that can cause very serious immune reactions, this discovery will better take care of these rare patients, as well as people with certain blood diseases or certain cancers. The latter can indeed temporarily lose the ANWJ antigen, without being genetically anwj-negatives.
