He found male liver cells in the livers of female patients, and this could only have come about from the male to female bone marrow transplant. Researchers had seen such things happen in laboratory dishes. This, however, was the first time it had been spotted in living humans. The discovery opens the way to a new kind of alchemy. Instead of a philosopher's stone that turns base metal into gold, there might be techniques that could reliably turn one kind of tissue into another.
Most organ transplants rely on a donor's death, and there are too many patients and too few donors.
The Hammersmith research suggests that faulty livers might one day be repaired with bone marrow stem cells. Ultimately it may be possible to regenerate a new liver using the patient's own stem cells. There are about 5,000 people in the UK awaiting organ transplants.