The World's Most Dangerous Blood Type

This episode of Real Science is brought to you by Curiosity Stream. Register today at Curiousstream.com/realscience and get free access to watch.nebula.com. We all know we should donate

blood

, but we probably don't do it as much as we should. Every year, nearly five million Americans need

blood

transfusions and would likely die without them. In the United States, approximately 32,000 pints of blood are used each day for people who lose blood during operations or traumatic injuries. Others need blood transfusions due to chronic diseases such as sickle cell anemia, so everyone needs transfusions throughout their lives.

The blood donation and transfusion network in any country is a hugely vital part of keeping sick or injured people alive and healthy. This wouldn't be so complicated if we all had the same blood

type

, but we don't. And some of us have blood

type

s so rare that any injury, any procedure, or any accident can be life-threatening. Imagine if your blood was so rare and unique that if you were to get hurt, al

most

no one else in the

world

who donated blood could save you. It is so rare and so valuable that it is necessary to conceal its identity to keep an endless stream of requests at bay.

So rare that scientists would do al

most

anything to get a pint of it and study it. For people who have the rarest blood type in the

world

, Rh null, this is their reality. It is the most

dangerous

blood type in the world because only 43 people in the world are found to have it. Meaning, if you get hurt, basically no one else's blood would be compatible with yours. Injuries that would be serious but treatable for everyone else would probably be fatal for you. Most of us have probably heard of the usual blood group system, or even know our own blood type.

O+, AB-, A+, O-. This classification determines who we can donate or receive blood to. There are a total of 33 different recognized classification systems, but most people only need to worry about the two most common, the ABO and Rh systems. The ABO system classifies blood based on the presence of antigens, antigen A and antigen B. It can have one or the other, both or neither. Antigens are glycoprotein markers embedded in the cell membrane and help the immune system distinguish between the body's own cells and foreign cells, such as viruses or bacteria. In blood type A, the A antigen is found on the blood cells themselves and an A or anti-B antibody is found in the blood serum.

In a B blood type, a B antigen is found on the blood cells and a B or anti-A antibody is found in the serum. Blood type AB has A and B antigens on the blood cells and none of the corresponding antibodies against them in the serum. And blood type O has no antigen in the cells but has antibodies A and B in the serum. When you donate blood, the red blood cells are separated from the plasma where the antibodies are found through a process called blood fractionation. This ensures that only red blood cells are donated and not their corresponding antibodies, as this would cause an adverse reaction in the recipient.

Your immune system will produce antibodies against any blood antigens that you don't have in your own blood. Therefore, a person with type A blood receiving B blood would have an ABO incompatibility reaction. The anti-B antibodies present in the patient's blood would agglutinate with the B antigens on the donated red blood cells, causing the blood cells to clump together and block the small blood vessels. The immune system would then attack the new blood cells and destroy them. It is rare for this to happen, but if it does happen it is serious and life-threatening. Transfusion is considered safe as long as the recipient's serum does not contain antibodies against the donor's blood cell antigens.

Therefore, if you have type AB blood, you are a universal recipient: you do not have any of the antibodies that would attack the blood of an A or B donor. However, this also means that you can only donate blood to other people who have A B blood. If you have type O blood you are a universal donor. You can donate your blood to A B or O without activating their immune system. But this is also the reason why people with O blood can only receive Type O blood. However, there are other antigens that must be considered in addition to those of the ABO system before safely donating or receiving blood.

This is where the rhesus system comes into play. The rhesus, or Rh system, is the second most important blood group system. These are the most important antigens, the most important being the D antigen. Although there are many other Rh antigens, RH-D is the most important because it is the Rh antigen most likely to produce an immune response. Depending on whether the RH-D antigen is present, each blood type is assigned a positive or negative symbol. Rh-D negative people can only receive Rh-D negative blood. But people who are Rh D+ can receive Rh D positive or Rh D negative blood.

The negative blood types, A negative, B negative, AB negative and O negative, are rarer than their positive counterparts. And although the D antigen is the most important in the Rh system, there are a total of 60 other Rh antigens, making it the largest of all blood classifications. And while these eight blood types are the most common way to describe our blood, each of these eight types can be subdivided much further. There are millions of varieties, each classified according to the exact antigens that coat the surface of our red blood cells. To know your exact blood type you would have to write it down antigen by antigen.

Fortunately for most of us, many of the antigens we have do not affect our ability to receive or donate blood because almost everyone else has them too. For example, more than 99.9% of people carry the antigen called Vel. So for most of us who donate blood to each other, we wouldn't have to worry about this antigen since it wouldn't trigger an immune response. But for every 5,000 people there is one who lacks the Vel antigen and who should not receive blood from the other 4,999. Their immune system recognizes the Vel antigen as foreign and if they are given Vel positive blood they could have kidney failure and possibly die.

But doctors screen for as many of these variants as possible to make sure they find the best match for a blood transfusion. But sometimes this best match is not really possible and that is why the rarer the blood, the more difficult things become. The rarest blood type in the world, Rh-null, is called Rh-null because it does not have any of the 61 Rh antigens present in the blood system that we discussed above. It is quite rare for some of the Rh system antigens to be missing in the blood, but the chances of all of them being missing are astronomically small.

Doctors call it golden blood because for anyone who has some rare Rh blood type, missing a few antigens here or there, Rh-null blood can be accepted where other, more typical blood types might not be. It has enormous life-saving capabilities, but for those who have it it can be a curse. Most of us probably take for granted that if we get hurt, the nearest hospital will be able to fix us. But if you're one of the few with Rh-null blood, life is inherently more

dangerous

. You cannot receive blood from anyone other than the 42 other people who exist who have the same blood type.

And of the people known to have it, only a handful of them are active donors and they are spread all over the world. And the logistics of shipping blood around the world are stupidly complicated. Bureaucracy and paperwork can delay things at borders, which can create a host of problems. Fresh blood has a shelf life of four weeks and must be stored at four degrees Celsius, which is a challenge during transport, especially to remote areas. This means that any delay at customs can render the blood unusable. And some countries have very restrictive rules regarding the importation of blood.

The United Arab Emirates, for example, will not accept blood into the country that does not come from the Gulf states. These types of logistics and bureaucracy make it very difficult for someone with rare blood to receive a transfusion, especially in a sudden emergency when they need blood quickly. For a Swiss man with Rh-null blood, this meant that when he was a child he couldn't go to summer camp or play outdoor sports because his parents feared he would be injured if he couldn't receive a blood transfusion. As an adult he cannot travel to countries without modern hospitals.

The only realistic way he can get around this danger is to continually donate blood, which means twice a year he donates blood to keep it in reserve in case he ever needs it. And he can't really donate much more than that because Rh-null blood also has some adverse effects. The Rh antigens that most of us have are thought to play a role in maintaining the integrity of the red blood cell membrane. Red blood cells lacking Rh antigens have an abnormal shape and increased osmotic fragility. This means that red blood cells break down faster than they should, causing hemolytic anemia.

This can cause fatigue, shortness of breath and jaundice and therefore makes frequent blood donation impossible. And because only a handful of people with this rare blood type donate it, it puts a huge burden on those who do when someone else needs this blood type. Because Rh-null blood can be donated to anyone with a rare combination of Rh-negative blood type, you may occasionally receive an urgent call to donate. The Swiss we mentioned earlier once received a call saying that a newborn baby urgently needed his blood type. To save the baby's life, he would have to go to the donation center.

This meant taking a taxi to Geneva and taking time off work, time that cannot be reimbursed due to blood donation laws in some parts of Europe. He was able to help in this case, but quickly realized that the cost and burden of donating his precious blood would ultimately fall on him. Anyone with this rare blood type receives the gift of being able to help someone in a time of need, the ability to help where no one else can. It's probably surprising to know that you've helped save someone's life. But this also comes with the unfortunate burden of being, in a sense, on call throughout your life, should the need for your blood arise.

This raises an interesting ethical question. It's up to you to donate blood at any time, whether you're in a client meeting, at your own wedding, or on vacation. At what point does your moral obligation to help someone in need begin and end? But for every person who would otherwise be doomed without this donated blood, its importance obviously cannot be underestimated. And this serves as a reminder that hospitals around the world depend on the good deed of blood donation to save lives, whether your blood is rare or not. Since the first blood transfusions in the 19th century, they have saved millions of lives and played a vital role in shaping our modern world.

In times of peace they have saved citizens from unfortunate accidents and in times of war they have saved the lives of countless wounded soldiers. During World War II, the American Red Cross transported nearly two hundred thousand pints of whole blood from the United States to Allied forces in Europe. More than fifty thousand pints of blood were needed for the soldiers who fought during the invasion of Normandy on D-Day alone. The level of coordination required to collect and transport so much blood is staggering, and you can learn more about logistics like this in Real Engineering's new "D-Day Logistics" series available exclusively on Nebula, the streaming platform created by the best . educational content creators, such as Wendover Productions, Medlife Crisis, BrainCraft and our other channel Real Engineering.

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