Why are some transplants successful and some unsuccessful?

Answer 1

Some transplants simply do not work. Until the transplanted organ is in place in the patient's body and connected, it is not possible to know if it is going to 'function' or not. At this stage, it is obviously not possible to go back. The length of time that the organ has been out of the body before transplantation adversely affects how the graft (organ) functions. Sometimes it affects grafts in very odd ways; the graft can be transplanted in appearing healthy, but does not work. If the patient is retransplanted, or if the organ is removed during an autopsy within a few days, the graft can by covered in small tumors, or hard patches, all in the space of days. (All organs are thoroughly checked for abnormalities before transplantation). So far it's not possible to tell if a transplant is going to be "successful" or not; it's still guesswork. Some transplants fail due to organ rejection (whether acute or chronic), some fail due to non-compliance with drug regimes, some fail for unknown reasons.