This rare blood type would save the lives of future newborns!
Blood group is a classification based on the presence or absence of antigenic substances covering the surface of red blood cells. These antigens vary by blood group system. It can be protein, carbohydrate, glycoprotein or glycolipid. Those are identification markersallowing the organism to detect invaders.
The ABO and Rh blood classification systems are the best known. They were identified in the early 20e century. However, in reality, there are many morebased on several types of cell surface antigens and their variants.
Lately the tragic loss of a newborn couple has revealed crucial information about a rare blood type, first spotted in humans 40 years ago. The deepening of the molecular identity of this new blood group would make it possible to prevent such tragedies.
The clinical impact of this rare blood group is still unknown
This new blood type is known as Er system. He was only spotted in 1982, and constitutes the 44e blood group. A version called Erb was identified six years later. Even though the existence of these antigens has been evident for decades, there is still not enough information about their clinical impact.
When a blood cell presents an antigen that the immune system considers non-self, it triggers a defense to eliminate the danger. An incompatibility between the blood group of the mother and the future baby can happen. In this case, antibodies cross the placentacausing hemolytic disease in the unborn baby.
Several methods can now be used to prevent, or even treat, hemolytic disease in newborns. These are essentially injections for pregnant women and blood transfusions for babies. However, in one of the cases mentioned in the study, a blood transfusion following a caesarean section did not save the life of the child.
The Er5 variant would provide an advantage against malaria
National Health Service Blood and Transplant (NHSBT) serologist Vanja Karamatic Crew and her team conducted research on these rare blood types. Their study was published in the journal Blood. By analyzing the blood of 13 patients showing suspicious antigens, they discovered five variations in Er antigens. These are Era, Erb, Er3, known variants, and Er4 and Er5, two new variants.
The researchers found that the PIEZO1 gene encodes cell surface proteins. Mice deprived of this gene die before birth. The blood cells of those from which it has been removed in their red blood cells are overhydrated and fragile. The results showed that PIEZO1 is required for antigen to be added to the cell surface.
The researchers noticed that the Er5 variant had a high prevalence in African populations. They suggest that this variant provides an advantage against malarialike other rare blood types found there.