What is Golden Blood?
Scientifically known as Rhnull, it is often referred to as "golden blood" because of its extreme rarity and value to others. It is known to be owned by 43 people in the world according to data from 2021. To understand why Rhnull is so rare and valuable, you need to pass a brief introduction to the world of blood types.
You've probably heard of the four main blood types: A, B, AB, and O. This grouping is determined by the presence of A and B antigens, which will trigger an immune response if red blood cells are introduced into someone who is not compatible. So, blood group A has antigens A, blood group B has B antigens, blood group AB has both antigens, and blood type O has neither of them.
In addition to antigens A and B, there are other proteins found in red blood cells called Rh factor, the presence or absence of which determines whether the blood type is positive (+) or negative (−). Although there are actually 61 blood group antigens (Rh antigens), the negative/positive division refers to the absence or presence of one Rh antigen – the Rh(D) antigen.
A person can only give blood to someone with compatible blood antigens.
So, people with Rh− blood can give blood to both Rh− and Rh+ recipients, since Rh− does not contain the troublesome protein. However, those with Rh+ blood cannot give Rh− recipients. Rh positive is much more common than Rh negative, although there is some variation in different populations.
Type O negative blood does not have any of the antigens mentioned here, so it will not elicit an immune response from everyone to whom it is given, and is considered a universal blood group. There are far more complex variants than this with hundreds of antigens playing a role, but let's say that so far is the most important thing that needs to be explained.
Why is it called "Golden Blood"?
In short, gold blood lacks Rh antigens. People with this blood type don't have or have mutations in the genes to build these proteins, so they miss every single one of them.
The first case of golden blood was identified in 1961 in an Australian woman who was part of the indigenous population. Since then, dozens of strange cases have been spotted, and scientists estimate that about 1 in 6 million people have it worldwide. No one knows for sure, but so far only 43 cases of people with this blood type have been confirmed.
The blood type is inherited and the Rhnull blood is no different. It is formed when there is a mutation in the RHCE gene inherited from each parent. This is a rare phenomenon known as "autosomal recessive inheritance," when a person inherits two copies of the mutated gene, one from each parent. [ref. 1]
Rhnull blood is considered a "universal" blood for anyone with rare blood types in the Rh system because it lacks any of the antigens that could cause alarm for the immune system. This means that Rhnull has a huge potential for blood transfusions. [ref. 2]
This rarest type of blood has applications in biomedical research, such as in the development of immunoglobulin-based drugs used to prevent rhesus disease. This is a condition in which antibodies in the blood of a pregnant woman attack the baby's blood cells. [ref. 3]
Can you donate and receive "golden blood"?
Yes, golden blood can be donated. Due to the lack of antigens in red blood cells, a person with Rh blood type O is considered a universal donor, and this blood can be donated to anyone with rare blood types in the Rh systems.
This rare type of blood is suitable for transfusion because it lacks common antigens and can be taken by anyone who needs a blood transfusion without the risk of reacting. Apparently, due to the very rarity, finding this type of blood type is extremely difficult.
For the same reason, if a person who is an Rh-zero carrier needs a blood transfusion, it can be extremely difficult to find a donor, and the blood is extremely difficult to transport internationally. Rh-zero carriers are encouraged to donate blood as insurance for themselves, but with so few donors scattered around the world and restrictions on how often they can donate, it also makes it difficult to have such blood.