The discovery of a new blood group, MAL, has solved a 50-year-old mystery. Researchers from NHS Blood and Transplant (Bristol), NHSBT's International Blood Group Reference Laboratory (IBGRL) and the University of Bristol identified the genetic background of the previously known but mysterious AnWj blood group antigen. The findings allow identification and treatment of rare patients lacking this blood group.
Some people can lack this blood group due to the effect of illness, but the rare inherited form of the AnWj-negative phenotype has only been found in a handful of individuals—though due to this discovery it will now be easier to find others in the future. 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. 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.
The AnWj antigen—an antigen is a surface marker—was discovered in 1972 but its genetic background was unknown until now. The new research, published in Blood , establishes a new blood group system (MAL), the 47th ever to be discovered, as home to the AnWj antigen. The research team established that AnWj is carried on the Mal protein.
More than 99.9% of people are AnWj-positive, and such individuals were shown to express full-l.