Introduction to Blood Type Classification
Even those with limited knowledge of hematology are familiar with the ABO and Rh systems for blood type classification. These systems categorize individuals based on the presence or absence of specific antigens on the surface of red blood cells, resulting in blood groups such as A, B, O, AB, A+, and B−. These classifications are crucial for determining compatibility in blood transfusions. However, it is often overlooked that ABO and Rh are not the only systems for blood type classification. In fact, there are 47 different systems, including MNS, Kell, and Duffy, which depend on the presence or absence of specific antigens and allow for the classification of individuals into nearly 390 different blood groups.
The Discovery of a New Blood Type System
Recently, the French Blood Establishment (EFS) announced the identification of a new blood type classification system by French researchers. This new system has been identified in only one patient so far, a woman of Guadeloupean origin. Consequently, scientists have named this new system “Gwada,” a nickname for Guadeloupe. This patient is currently the only person in the world identified with the “Gwada negative” blood type.
Implications of the Discovery
“This patient is the only one in the world at present, but now that we are aware of this new rare blood type, we have the means to search for it and hope to find other compatible individuals,” explains Thierry Peyrard, a medical biologist at the EFS, in an interview with France Inter. Finding other carriers of this blood type could be crucial for this patient, as she may face challenges in finding a compatible donor if she requires a transfusion.
The Quest for Rare Blood Types
For several years, the EFS has been on a mission to identify “rare blood.” A blood type is considered rare if it is present in less than 0.4% of the population. “Today, we describe 390 different blood groups, of which 250 are considered rare,” explained Professor Jacques Chiaroni, a hematologist and director of the EFS in the PACA region, in a 2024 interview with France Info outre-mer.
Geographical Variations in Blood Types
The frequency of blood types varies among different human groups, and a blood type that is rare in some ethnic groups may not be rare in others. “There is a true geography of blood types,” continues Professor Chiaroni. For example, “a European who is Rh-negative and goes to live in China cannot be transfused there, as Rh-negative is almost nonexistent.”
Genetic Diversity and Blood Type Challenges
Due to their greater genetic diversity compared to other ethnicities, individuals of African descent are particularly exposed to this diversity of blood types, which can make it more challenging to find compatible blood for transfusions. The situation is even more difficult for people of African descent living outside Africa, whether due to immigration or the transatlantic slave trade. For instance, the Duffy negative blood group is very common in Africa (more than 70% of the population carries it) but is almost nonexistent outside the African continent. The discovery of the “Gwada negative” blood group in Guadeloupe is, in a way, a legacy of the island’s past involvement in the slave trade.
Efforts to Increase Blood Donation Diversity
In 2022, the EFS launched a campaign to encourage blood donations from populations of African descent, who not only are more likely to carry rare blood types but also generally participate less in blood donation. “We need to increase the diversity of blood donors so that, in countries where history has led to significant biological and cultural diversity, such as France and particularly the overseas departments and regions, the donor population resembles the recipient population,” explains Professor Chiaroni.
Statistics on Rare Blood Types in France
It is estimated that 700,000 people in France carry a rare blood type. “Between 13,000 and 15,000 people are identified in a registry of the National Reference Center for Blood Groups,” continues Professor Chiaroni. Individuals with rare blood types are particularly valued by EFS services; they are encouraged to donate blood regularly and to encourage their relatives, who may also carry the same rare blood type, to do the same. Additionally, while standard blood bags are preserved for only 42 days, rare blood bags are “frozen at −80 degrees to be used for at least 30 years,” concludes Professor Chiaroni.
This article was originally published on JIM.fr, a member of the Medscape network.
🔗 **Fuente:** https://francais.medscape.com/s/voirarticle/3613061