United States: A new curiosity has erupted among the scientists after they got a hint about the presence of a new blood group in humans. This groundbreaking discovery was reported after, in 1972, a pregnant woman’s blood sample confounded doctors due to the enigmatic absence of a surface molecule, a hallmark of all red blood cells known at the time.
Fast forward five decades and this perplexing deficiency has led researchers from the UK and Israel to define a completely novel blood group system in humans, according to sciencealert.com.
“This breakthrough represents a monumental achievement, the culmination of decades of diligent collaboration, allowing us to finally categorize this blood group system and optimize care for rare yet significant patients,” said Louise Tilley, a hematologist from the UK National Health Service, who has dedicated nearly 20 years to investigating this obscure anomaly.
While the general population is most acquainted with the ABO blood system and the Rh factor (the positive or negative sign), in reality, humans possess numerous blood group systems determined by a wide array of proteins and sugars that form the surface of red blood cells.
Our bodies employ these antigenic structures for essential identification, marking cells as ‘self’ or ‘foreign,’ a crucial distinction when it comes to transfusion medicine. Any mismatch between donor and recipient can trigger life-threatening reactions, turning a lifesaving procedure into a fatal one.
Most major blood groups were discovered in the early 20th century. However, blood groups uncovered later, such as the Er system, formally recognized in 2022, typically affect only a minuscule portion of the population. This is likewise the case with the new system, as per sciencealert.com.
“The challenge lay in the extreme rarity of these genetic cases,” explained Tilley.
Earlier research revealed that over 99.9 percent of individuals possess the AnWj antigen, which was conspicuously absent from the 1972 patient’s blood. This antigen is located on the myelin and lymphocyte protein, inspiring the researchers to christen the new system as the MAL blood group.
If a person inherits mutated versions of both MAL genes, they end up with an AnWj-negative blood type, akin to the pregnant patient. However, Tilley and her team also identified three individuals with this rare blood type who did not harbor the mutation, suggesting that in some instances, blood disorders may suppress the antigen.
“MAL is an exceedingly small protein with distinctive characteristics that complicated its identification. This forced us to pursue numerous investigative pathways to gather the necessary evidence to confirm this blood group system,” clarifies Tim Satchwell, a cell biologist at the University of the West of England.
After decades of inquiry, the team verified their findings by introducing the typical MAL gene into AnWj-negative blood cells, which subsequently displayed the AnWj antigen.
The MAL protein is recognized for its crucial function in stabilizing cellular membranes and aiding transport within cells. Interestingly, previous studies showed that AnWj isn’t present in newborns but emerges shortly after birth.
In the study, all AnWj-negative patients exhibited the same genetic mutation, though none showed additional cellular abnormalities or diseases linked to it, according to sciencealert.com.
Now that the genetic markers for the MAL mutation have been identified, it is possible to screen patients to determine if their negative MAL blood type is hereditary or the result of suppression, potentially signaling another underlying health issue.
These rare blood anomalies can profoundly impact patient outcomes. The more we unravel their complexities, the better we can save lives.
The study has been published in Blood.