There is an extremely rare blood group known as Rh-null, often nicknamed “golden blood.” This type is so uncommon that only around 50 people in the entire world are known to have it.
What makes it special is that it lacks all Rh antigens more than 50 different ones on the surface of its red blood cells.
Why It Matters So Much
Rh antigens are proteins or sugars on red blood cells that tell the immune system what is “self” and what is foreign.
Because the “golden blood” type has none of the Rh antigens, it can be transfused into almost anyone with rare Rh-based profiles without triggering a typical immune rejection. That makes it extremely valuable in rare blood transfusion cases. However, it’s not a free-for-all: Rh-null individuals can only receive blood from other Rh-null donors. Because so few people have it, that makes finding compatible blood for them extremely difficult.
The Origins and Genetics
Rh-null was first identified in a woman in Australia in 1961. It is caused by a rare genetic mutation: individuals must inherit defective versions of the genes responsible for building Rh antigens. Because of this, very few people naturally carry the “golden blood” type.
Efforts to Grow It in the Lab
Because natural donors are so rare, scientists are racing to find a way to manufacture Rh-null blood in the lab. One research group used CRISPR-Cas9 gene editing to remove several problematic blood group antigens, including Rh, ABO, and others, to create ultra-compatible cells. But because gene editing is heavily regulated and controversial, they are also developing lab-grown red blood cells from stem cells donated by people with Rh-null blood.
Scientific Challenges
Growing fully mature Rh-null red blood cells outside the human body isn’t easy. In some lab experiments, cells with no Rh antigens failed to develop properly — their membranes broke down or they didn’t multiply well.
Immunologists are especially concerned about maintaining structural integrity in these artificially produced cells.
Clinical Trials Underway
To push their work forward, researchers launched a clinical trial called RESTORE, which is testing lab-grown red blood cells derived from donated stem cells (without using gene editing) to see if they are safe in humans.
The trial is a major milestone — but it took years of research to reach this point. Although drawing blood from donors is still more efficient and cost-effective, lab-grown “golden blood” could become a crucial option for people with extremely rare blood profiles.
The Impact on Transfusions
If lab-grown Rh-null blood becomes available at scale, it could be a lifeline for patients with very rare Rh blood types. Because Rh-null does not trigger certain immune reactions, it could potentially serve as a universal compatible source for difficult transfusions. For people who naturally have Rh-null, the existence of lab-grown supply could also offer a backup. Some of these individuals already store their own blood, since it’s nearly impossible to find a match in an emergency.
Why This Research Is So Important
The quest to create “golden blood” in the lab is not just a scientific feat — it’s a potential game-changer for transfusion medicine. For patients with rare blood types and for future emergency care, increasing the availability of Rh-null blood could reduce risk and save lives. This ongoing work also highlights how advanced biotechnology — especially gene editing and stem cell research — is being applied in the real world to solve life-and-death medical problems.
