Blood donors may no longer be needed in the future after scientists showed it was possible to create blood from stem cells.
The 20 year project could pave the way for an unlimited number of blood and immune cells for transplants, simply by reprogramming a patient's own skin cells.
The research, reported in the journal Nature, holds out enormous promise for developing personalised treatments for blood disorders, drug-screening and reducing shortages of donated blood.
Dr Ryohichi Sugimura, of Boston Children's Hospital, said: "This gives us the potential to have a limitless supply of blood stem cells and blood by taking cells from universal donors. This could potentially augment the blood supply for patients who need transfusions.
"This step opens up an opportunity to take cells from patients with genetic blood disorders, use gene editing to correct their genetic defect and make functional blood cells."
For patients receiving treatment for cancer, blood disorders, after accidents or during surgery, or new mums who lose blood in childbirth, blood is an absolutely essential part of healthcare.
But NHS Blood and Transplant - the service which collects, tests and processes blood for hospitals across England -says that while hospitals have the blood needed to treat patients there is a need for more new donors.