Science
Why can Rh-null donors never receive most blood?
- They lack every Rh antigen
- They clot too fast
- They are always ill
The answer is They lack every Rh antigen. Golden blood gives to almost anyone and can accept from almost nobody.
Because they have none of the Rh antigens at all - not just D, but the whole system, over sixty of them. That makes their cells invisible to almost any recipient's immune system, so their blood can go to people with rare Rh types nobody else can help. It also means their own immune system will attack essentially any blood but Rh-null.
Fewer than fifty people with it have ever been identified, and only a handful are active donors. They are asked to bank their own blood before surgery, and the international rare-donor registries exist largely to move a few units across borders for individual patients - a system in which a person in one country can be alive because a specific named stranger in another gave blood on schedule for decades.
It is not free of cost either. Lacking Rh proteins destabilises the red cell membrane, so people with Rh-null blood have a mild chronic anaemia. They are simultaneously the most valuable donors in the world and among the most precarious patients, which is why the informal name - golden blood - carries a certain irony for the people who have it.