New blood type group discovered after 50 years

Most are familiar with the ABO blood type group, and some might know Rh (Rhesus). Recently, however, scientists from the UK’s National Health Service discovered a new type: Mal.

It determines whether blood contains the AnWj antigen, which researchers discovered in 1972. Over 50 years later, they discovered its link to the Mal gene and based a new blood type group on it.

This breakthrough could save lives as it could prevent mismatched transfusions between AnWj-negative and AnWj-positive patients. 

How did the scientists discover the new blood type group?

The NHS website says over 99.9 percent of people worldwide are AnWj-positive, meaning their red blood cells express full-length Mal genes.

The rare few who are AnWj-negative usually suffer from blood disorders or cancers that suppress antigen expression. Even rarer are those who are AnWj-negative due to hereditary factors.

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Decades of research and whole exome sequencing allowed researchers to confirm such rare-inherited diseases stem from missing Mal genes. 

Eventually, they linked Mal to the AnWj antigen, leading to the creation of a new blood type group around it. 

If an AnWj-negative person receives AnWj-positive blood, their immune systems could react and cause complications. 

That is why researchers are developing new genotyping tests to identify AnWj-negative individuals and ensure they receive compatible blood during transfusions.

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Louise Tilley, Senior Research Scientist, IBGRL Red Cell Reference at NHS Blood and Transplant, said:

“The genetic background of AnWj has been a mystery for more than 50 years, and one which I personally have been trying to resolve for almost 20 years of my career.”

“It represents a huge achievement, and the culmination of a long team effort, to finally establish this new blood group system and be able to offer the best care to rare, but important, patients.”

“This development will help identify these rare donors and help patients in the future,” Ash Toye, Director of the NIHR Blood and Transplant Research Unit, stated.

You may read more about the new blood type group study in the journal Blood.