UK scientists discover new blood group MAL, solve 50-year-old mystery

A team of researchers from NHS Blood and Transplant (NHSBT) (Bristol), NHSBT’s International Blood Group Reference Laboratory (IBGRL) and the University of Bristol have discovered a new blood group, MAL, which has solved a 50- year-old mystery.

The researchers have identified the genetic background of the previously known but mysterious AnWj blood group antigen. The AnWj blood group antigen was first discovered in 1972 but its genetic background was unknown until now.

The new blood group system (MAL), is the 47th ever to be discovered, as home to the AnWj antigen. The research team led by senior research scientist Louise Tilley, has developed a genetic test to identify patients missing the AnWj antigen.

The discovery will help in taking better care for rare patients and aid in finding compatible blood donors. “It's challenging to quantify the exact number of people who will benefit from this test. However, NHSBT is the last resort for around 400 patients each year worldwide," Tilley, who has dedicated 20 years to this project, was quoted as saying by BBC.

“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,” said Tilley of NHS Blood and Transplant.

“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, she added.

The two best known blood group systems are ABO and Rh but blood is more complex and matching across the other groups can be lifesaving, a press release by University of Bristol said.

If people who are AnWj-negative receive AnWj-positive blood they could have a transfusion reaction, and this research allows development of new genotyping tests for detecting such rare individuals and reducing the risk of transfusion-associated complications, it added.

Ash Toye, Professor of Cell Biology in the School of Biochemistry and Director of the NIHR Blood and Transplant Research Unit in red cell products at the University of Bristol, said: “It’s really exciting we were able use our ability to manipulate gene expression in the developing blood cells to help confirm the identity of the AnWj blood group, which has been an outstanding puzzle for half a century. This development will help identify these rare donors and help patients in the future.”

The new research will be published by Blood, the journal of the American Society of Hematology.