Researchers Discover New Human Blood Group System after 50 Years of Investigation

CGC News Reporter January 6, 2025

A new human blood group system has been identified after over 50 years of research, stemming from the mysterious case of a pregnant woman whose blood, sampled in 1972, was found to be missing a surface molecule found on all other known red blood cells at the time. This discovery has led researchers from the UK and Israel to officially describe the new blood group system, named MAL, in a paper published in September.

The absence of the AnWj antigen in the 1972 patient’s blood, which is present in more than 99.9% of people, initially baffled doctors. The antigen is found on a protein involved in myelin and lymphocytes, leading the team to name the new blood group the MAL system.

This blood group is incredibly rare and affects only a small number of individuals, making it a challenging area of research, as UK National Health Service haematologist Louise Tilley, who spent nearly 20 years studying the anomaly, explained.

The discovery is significant, as it will help medical professionals provide better care to patients with rare blood types, preventing life-threatening reactions during blood transfusions. While blood groups like the ABO system and rhesus factor are well-known, this new blood group adds to the growing list of lesser-known systems that highlight the complexity of human blood.