“Gwada negative”: what is this new blood type identified in a Guadeloupean woman?

By The New Obs with AFP

Published on June 21, 2025 at 11:58 a.m.

Blood types A+A-, B+, B-, AB+, AB-, and O+ are certainly the best known, but they are not the only ones. In recent years, dozens more have been identified. The latest was in a French woman of Guadeloupean origin, identified as the only known carrier of this new blood type, dubbed "Gwada negative," an official from the French Blood Establishment (EFS) said on Friday, June 20, confirming a report from France Inter radio.

As early as 2011, a "very particular" and "unknown" antibody was found in this patient, but the resources at the time did not allow for further research, explained Thierry Peyrard, a medical biologist pharmacist, head of the EFS for the quality and safety of blood products and a researcher at Inserm.

Scientists were able to "unravel the mystery" from 2019, thanks to "very high-throughput DNA sequencing" , which highlighted "a genetic mutation" , he added.

The discovery of this new group "was made official at the beginning of June in Milan by the International Society of Blood Transfusion (ISBT)" , the EFS announced on social media.

Now in her sixties, the patient was "54 years old, living in Paris" and was undergoing the usual tests before surgery when the unknown antibody was detected, Thierry Peyrard recalled.

"There is only one who is compatible with herself today in the world" for the moment, while for other rare blood groups, a small group of people can be identified, such as siblings. This woman "is undoubtedly the only known case in the world," the specialist said.

"This blood type is inherited from her father and mother," who each had "the mutated gene ." Like their parents, the patient's siblings "carried only one allele" and therefore did not have this blood type, which is declared "with the two identical genes."

As Thierry Peychard explained in detail to "Le Parisien" , this discovery is important in several ways, particularly in the case of transfusions, since an incompatibility between donor and recipient can have serious consequences, even death. "It is also important for women who are expecting children: if the mother has rare blood, she can produce an antibody that can be directed against her child."

This discovery also offers new perspectives in cancerology, neurology and even rheumatology. "What is fascinating is that this discovery does not only have functional results. It allows us to better understand pathologies," explains Thierry Peychard.

The discovery led to the naming of "a new family, called PIGZ, which became the 48th blood group system in humans ." The best-known system, ABO, dates back to 1900.

The name "Gwada negative," which refers to the patient's Guadeloupean origins and "sounds good in all languages," "really appealed to experts," according to Thierry Peyrard. With his colleagues, thanks to the implementation (currently underway) of a special protocol, he hopes to "find other people [from the same group] in Guadeloupe in particular, among blood donors."