A groundbreaking discovery has revealed a new human blood group, described after decades of research that began with an unusual finding in a pregnant woman’s blood sample back in 1972. The woman’s blood lacked a surface molecule, known as the AnWj antigen, which is found on the red blood cells of nearly all other people. This absence has led researchers from the UK and Israel to establish a new blood group system called the MAL blood group.

The team, led by UK National Health Service hematologist Louise Tilley, published their findings in September, marking the culmination of nearly 20 years of research. Tilley highlighted the importance of the discovery, emphasizing how it would aid in providing the best care for rare patients with this unusual blood type.

The human blood group system is based on various antigens present on red blood cells, such as those in the ABO system and the rhesus factor. These antigens act as identification markers to distinguish between ‘self’ and ‘foreign’ cells. A mismatch between blood types during a transfusion can lead to severe reactions or even death.

While most major blood groups were identified early in the 20th century, smaller, rarer systems like the MAL group, discovered by this research, affect only a small number of people. The research team identified the genetic mutation that causes the absence of the AnWj antigen in these rare individuals. The mutation affects the MAL gene, which produces a protein vital for stabilizing cell membranes and aiding in cell transport.

Through decades of research, the team found that the MAL mutation is linked to AnWj-negative blood, a rare trait seen in just 0.1% of the population. The discovery opens new avenues for testing patients and understanding the genetic causes of rare blood types, which could provide insights into other underlying medical conditions. With this new understanding, doctors can better manage blood transfusions and provide tailored care for patients with MAL blood.

This new blood group discovery is a significant step toward improving transfusion safety and understanding rare blood disorders, ultimately saving lives.