But to transplant between identical twins is not always feasible and therefore in 1959 the same group in Boston moved to transplanting between non-identical twins. This was only possible with controlling the immune system so that the organ would not be rejected.
This was accomplished using total body irradiation. Total body irraditation in itself is very morbid and really not an option.
The answer was in the use of medications, such as 6 Mercaptopurine, an antimetabolite that had been tested in rabbits previously with some success.
