New Blood Group Discovered by Scientists Solves 50-Year-Old Mystery

A New Blood Group

A research team finally broke through a 50-year-old mystery, by identifying a new blood group named MAL. Blood group is the term used to refer to the entire blood group system, that constitutes red blood cell antigens whose specificity is controlled by a series of genes, as per a paper published in the National Library of Medicine. Almost 50 years ago, a pregnant woman's blood group was tested and was revealed not to have a highly prevalent red blood cell antigen, leading to a new blood group, IFL Science reported. After further analysis, experts discovered that only a handful of people worldwide had this arrangement. For multiple decades now researchers have been trying to find the root cause behind this disposition. A team led by NHS Blood and Transplant (NHSBT) scientists in South Gloucestershire and supported by the University of Bristol, after multiple examinations has found the genetic background behind the missing antigen in the unique arrangement, potentially closing the decades-long enigma, BBC reported. 

AnWj Antigen

The antigen found missing from the pregnant woman's blood system was named AnWj by experts, IFL Science reported. As per researchers, most individuals lack the AnWj antigen because of ailments like cancer and hematological disorders. "The AnWj-negative phenotype is usually caused by transient suppression of antigen expression, associated with certain hematological disorders and malignancies," the team explained in their study, IFL Science reported. "Such suppression of blood group antigens, with associated antibody production against the suppressed antigen, is an established phenomenon, seen for example in Kell, Kidd, and LW systems. In such cases, it has been hypothesized that acquired reduction of antigen expression on the patient’s red cells leads to the development of the antibody, typically during pregnancy or following transfusion." Scientists have also noted multiple individuals not carrying this particular antigen because of genetic causes. The NHSBT team in their study identified five individuals, many of whom were from the same family, who did not carry the antigen due to their genes. 

Discovery of MAL Blood group

Researchers found through exome sequencing, that the AnWj antigen lived on a myelin and lymphocyte protein, known as the MAL gene, Science Alert reported. This made the researchers decide to call the AnWj negative blood system, the MAL blood group. "AnWj-positive individuals were shown to express full-length MAL on their red cell membranes, which was not present on the membranes of AnWj-negative individuals, whether of an inherited or suppression background," the team continued, IFL Science reported. "Furthermore, binding of anti-AnWj was able to inhibit binding of anti-Mal to AnWj-positive red cells, demonstrating the antibodies bind to the same molecule."

Test to Determine the Blood Group

Researchers conducted many tests before determining the genetic background of the AnWj antigen, Science Alert reported. The AnWj-negative patients in the study had the normal MAL gene injected into their blood cells by the experts. The study stated that the MAL gene effectively delivered the antigen to the subject's blood cells. This implied to them that the MAL gene and AnWj antigen have a connection, further proving their theory.

Impact of This Discovery

The results from the study have been used by NHSBT’s International Blood Group Reference Laboratory to develop a test that will identify patients with the missing antigen, BBC reported. As per researchers, this test would be a lifesaver for patients who could react against a blood transfusion and also aid in finding matching blood donors. "Anything we can do to make our blood much safer and a better match for patients is a definite step in the right direction," Philip Brown, who works at the laboratory stated.