In 2011, a woman from the French overseas region of Guadeloupe underwent routine tests before a surgery. Strikingly, doctors could not identify her blood group, which was so unique that they did not find any matches even from her family.1<\/p>\n
Halfway across the world in India, doctors recently faced a similar challenge upon testing a woman\u2019s blood before she underwent a surgery.2 Although tests revealed that her blood group was O positive, none of the donor samples were compatible with her blood. <\/p>\n
A person\u2019s blood group<\/a> is determined by the antigens they carry on their red blood cell (RBC) surface. The most familiar blood groups\u2014A, B, and O\u2014stem from the commonly found A and B antigens, while the Rhesus factor dictates Rh-positive or -negative blood groups.3,4 However, these are just two of the common blood group systems and some of the many antigens that influence blood grouping in individuals. <\/p>\n Martin Olsson, a transfusion medicine researcher at Lund University, works to make sure that blood transfusions, stem cell transplants, and organ transplants are matched correctly between donors and recipients. His team also explores the possibility of developing universally-compatible blood.<\/p>\n Roger Lundholm <\/p>\n \u201cIn total, there are almost 400 different blood group antigens,\u201d said Martin Olsson<\/a>, a transfusion medicine researcher at Lund University. \u201cIn general, [one has a rare blood group when] that patient\u2026lacks a high frequency antigen.\u201d <\/p>\n Analyzing the DNA of the Indian woman revealed that she carried a genetic variant resulting in the loss of a commonly found Cromer antigen on her RBCs. The patient from Guadeloupe similarly lacked the prevalent Emm antigen on her RBCs.5 <\/p>\n While the absence of some other Cromer antigens has been reported previously, the Guadeloupean woman is the only person in the world known so far to carry a blood type without the Emm antigen, leading to the recognition of a 48th blood group: While her blood group is Gwada-negative, that of all the potential donors tested is Gwada-positive. <\/p>\n Olsson and others in the field employ a suite of genomic and molecular techniques to identify and characterize the antigens underlying rare blood types. This not only unravels deeper insights into the biology of blood groups but can also help screen other people with possible rare blood types, setting them up as potential donors.<\/p>\n How Do People with Rare Blood Groups Get Transfusions?<\/p>\n A person\u2019s immune system recognizes their own antigens as \u201cself.\u201d However, receiving blood containing unfamiliar antigens results in the body treating them as invaders and mounting an immune response, including developing antibodies against the foreign antigens.6 <\/p>\n As such, a person whose RBCs do not carry a particular antigen would need blood from a donor who also lacks the same antigen. Several hospitals across the world are equipped with a database describing potential donors with rare blood types.<\/p>\n However, both the Indian and Guadeloupean women are the only known people with their respective blood types on the planet so far: They are only compatible with themselves. \u201cThis is an absolutely exceptional case,\u201d said Olsson, referring to the findings from the Guadeloupean patient. \u201cMy prediction is that there are other people out there with the same blood group\u2026but we certainly haven’t found them yet.\u201d <\/p>\n Until that happens, Olsson said that doctors may need to treat the patients with supplements to boost their hemoglobin levels so that they can donate their own blood. This blood could be stored and used for an autologous transfusion<\/a> if the need arises. <\/p>\n Studying Rare Blood Groups<\/p>\n![\"Martin](\"https:\/\/www.newsbeep.com\/us\/wp-content\/uploads\/2025\/09\/martin-olsson-m.jpg\" "\\"Martin")
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