Jasmine Zambrano has a handful of blood brothers scattered throughout the world. He doesn't know who they are or where they live or how many they add up. But she does know that they are the only ones who share a strange blood group with her. And they are the only ones that can save your life.
In the case of needing a transfusion, Jasmine can only receive blood from the Rh null group, a rare type among the rare ones of which only 50 cases have been documented since its discovery in 1961. But this Barcelona is calm because she knows that an international network watches because people who, like her, have a special blood group can always have a compatible donation. These are people with blood Bombay, Diego b-, Cartwright Yt (a -) ...
If you ask around, many people will say they know what their blood is like. They will tell you that it is A +, 0-, B + ... However, it is a half truth: the credentials of our blood are much more complex, since they are not only determined by the best known blood systems: the ABO and Rh .
In fact, there are more than 300 badges (antigens) that may or may not be present in the outer membrane of our red blood cells, explains Eduardo Muñiz , director of the Immunohematology laboratory of the Blood and Tissue Bank of Catalonia and coordinator of the Working Group on Rare phenotype red blood cells of the Spanish Society of Blood Transfusion.
The vast majority of them are very frequent. That is, they appear in almost the entire population of a given territory. But, for different reasons, some individuals lack one or more of these common markers in their red blood cells. And that makes his blood considered rare.
"They are people who do not have a blood group that is present in 99.9% of the people around them," says Muñiz, who stresses that "the strange thing is not having it."
Possessing a particular blood , however, does not imply any disease. Moreover, most people with a group like Duffy a negative or Langereis negative never know that a special blood runs through their veins. Problems only appear if these people have contact with a blood that is "incompatible with theirs," explains Irene Lucea , a hematologist who specializes in rare phenotypes and is responsible for Donor and Patient Immunohematology at the Community Transfusion Center in Madrid.
In a first episode, the body recognizes the foreign blood marker as a foreign agent and, therefore, develops specific antibodies against it, the specialist clarifies. But, if there is a second encounter, he continues, the alien marker will cause an alert in the body's natural police , which will attack the blood received and, therefore, will put the patient at risk.
They are people who do not have a blood group that is present in 99.9% of the people around them
Eduardo MuñizTherefore, before each transfusion - or in pregnancies - a study of the patient's blood profile is made. And, if it is discovered that their blood is particular , a compatible donor is sought or the stock of rare bloods that are frozen in the Transfusion Centers of Catalonia, Madrid, Galicia, Valencian Community and the Basque Country is used.
According to data from the Working Group of rare red blood cells of the Spanish Society of Blood Transfusion, in April 2019 there were 1,108 cryopreserved units of rare blood groups in our country and a total of 961 donors available to be called in an emergency situation .
That was the case of José Antonio Carrasquilla , who, from Fuenlabrada, put his veins without thinking at the service of a pregnant woman who needed blood from his same group, Kp (b-), in Andalusia. In the end, the transfusion was not necessary, but its precious blood - only one in 10,000 people in Spain has it - was kept in the Transfusion Center of Madrid, where, at 80 degrees below zero, more than 350 units of custody are guarded. rare phenotype
"I would do it again," he emphasizes. «How can I not collaborate with someone who needs help and who is in my same situation?».
Whenever possible, "the tendency is to use fresh blood instead of frozen units," says Lucea. The reason, he clarifies, has nothing to do with the quality of the product, but it is purely practical: "Thawed blood must be used in less than 24 hours," while fresh can be kept refrigerated for more than a month and, if not used, freeze later.
Of the 72 cases that required unusual blood in 2018, only 28 received a defrosted unit. "We try not to miss a drop," adds Muñiz, who, like the rest of specialists in rare phenotypes, tries to make both the available stock of units and the list of donors more and more nourished.
To do this, these hematologists not only recruit patients whose particularity has already been discovered, but also try to uncover new cases among the relatives of these people or, even, through random searches among conventional donations. «This strategy is a very laborious process, which seems to look for a needle in a haystack. But it's worth it, ”says Lucea, who once found two Kp (b-) profiles after analyzing almost 30,000 samples by hand.
It was in a similar process, about five years ago, where Jasmine Zambrano - today is 37 - discovered that his blood was not from the heap. "I have a disorder that causes me to accumulate an excess of iron, so they recommended me to donate and on one of the first visits they realized that my blood group was very rare," he recalls.
"This is a really exceptional phenotype, one of the most sought after," confirms Muñiz. This woman "lacks the entire Rh system , " discovered by Karl Landsteiner in the 1930s and one of the main blood systems used in Medicine.
It is a bit scary to think that there are few people in the world that have your blood
Jasmine Zambrano"At first I was afraid, really," says Zambrano, who since he found out, always carries with him a plaque that warns of his condition. «It is a bit scary to think that there are few people in the world who have your blood. But, on the other hand, knowing that you can help someone who needs it also gives a lot of satisfaction ».
Antonio Carrasquilla also claims to feel a certain vertigo when he thinks that conventional blood does not run through his veins. "I thought it was simply A +, the most common blood in Spain, but what a surprise I got," says this Madrid, who discovered the peculiarity of his blood after uncovering the case of his brother Aurelio. Another of her sisters is also Kp (b-), but no one else in the family has inherited that particularity from her red blood cells. "I donate from time to time, in case it is necessary for mine or for any other," he emphasizes.
Blood is closely linked to ethnicity, so that phenotypes that are very rare in a given population may not be so much in others. For example, in Southeast Asia, being RhD negative is really rare, with an incidence of less than 0.1%, while in our environment it is estimated that this particularity is around 15%.
Globalization, however, is changing the landscape and relocating cases that previously only affected a certain latitude. “About 10 years ago we realized that we needed people who could donate Diego b negative blood, a phenotype that occurs especially in Latin America and for which we had no reservations,” says Muñiz. "We did a campaign and we managed to find, but now we face a similar problem with people of African origin," says the specialist, who has already launched an initiative to try to find those hidden hematological treasures.
For the system to work, remember, "very close collaborative work with other countries is necessary." Since 2009, Spain is part of the International Network of 27 countries that the World Health Organization coordinates from Bristol (United Kingdom). In that time, Spain has supplied 50 units abroad (Portugal, Norway, Israel, Sweden, United Kingdom, Japan and Iran have been the recipients) and has received four: two from France, from people of African origin, and two others that They were brought from Japan to Barcelona.
"It's very complicated. We are talking about groups that perhaps only have one person in a million, ”says Muñiz. "We cannot improvise, but at all times we have to know what blood is available and where it can be located."
This wired system gives "tranquility" to Jasmine, who knows that there is "a network of donors" and "frozen blood" in case one day he needs it. Although she read fairy tales as a child, she could never imagine that true blue blood did exist ... and that it also ran through her veins.
Duffy, Kell or how to call the red blood cells
Since, at the beginning of the 20th century, Landsteiner discovered the ABO system, a total of 38 blood systems have been described. Many of them have been baptized with curious names, which relate to the place or the patient that allowed their discovery. Thus, the Duffy system, described in 1950, owes its name to Mr. Duffy, a patient with hemophilia whose blood was special. The Kell system, discovered in 1946, also received that name from Kelleher, the last name of a woman with pregnancy problems. Lutheran, on the other hand, is due to a transcription error and Bombay, because in that area of India the antigen is a little less rare.
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