Scientists Discover New Blood Group, Solve 50-Year-Old Mystery

A team of scientists from NHS Blood and Transplant (NHSBT) and the University of Bristol has identified a new blood group system called MAL. This breakthrough solves a 50-year-old mystery surrounding the AnWj blood group antigen, first discovered in 1972.

The research team, led by senior research scientist Louise Tilley, has developed a genetic test to identify patients missing the AnWj antigen. This innovation will enable better care for rare patients and facilitate finding compatible blood donors. Tilley, who has dedicated 20 years to this project, told BBC, “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.”

The discovery has far-reaching implications, benefiting patients worldwide. NHSBT's International Blood Group Reference Laboratory in Filton provides countries with antibodies for research and has developed a test that can be added to existing genotyping platforms.

Key findings of the research:

• AnWj Antigen: The team identified the genetic background of the AnWj antigen, allowing for a better understanding and treatment of rare patients lacking this blood group.
• MAL Blood Group System: The discovery establishes MAL as the 47th blood group system, home to the AnWj antigen.
• Genetic Cause: Researchers found homozygous deletions in the MAL gene associated with the inherited AnWj-negative phenotype.
• Transfusion Safety: The study enables the development of new genotyping tests to detect rare AnWj-negative individuals, reducing transfusion-associated complications.

Blood group antigens are proteins on red blood cells, and a lack of these can lead to severe reactions during transfusions. Philip Brown, a laboratory technician and leukaemia survivor, stressed the importance of the discovery. “Having undergone multiple blood transfusions and a bone marrow transplant, I understand firsthand the critical need for safer blood matches,” Brown told BBC.

Nicole Thornton, Head of the Laboratory, noted the international significance of this discovery. “Unraveling the genetic basis of the AnWj antigen has been a major challenge. With this breakthrough, we can now design genotyping tests to identify patients and donors with this rare antigen,” Thornton explained.