In 1960 Sir Roy Calne travelled to Boston to study 6 Mercaptopurine. He was an English transplant surgeon with a vision. He had been using 6 Mercaptopurine in dogs with success.
In 1961 they attempted a non-identical kidney transplant using 6 Mercaptopurine, or Azathioprine as it was ultimately named. Sadly the patient died of overwhelming infection.
The second patient did as well, but then utlimately a third pateint survived and this really opened the door to transplanting organs from one donor to another, across immunological barriers using medications to reduce the risk of rejecting the organs.
