Final answer:
Matching donors and recipients is crucial in organ transplantation to prevent tissue rejection. Blood relatives are preferred as organ donors because of genetic similarities. Immunosuppression is used to prevent rejection, although it comes with risks.
Step-by-step explanation:
In organ transplantation, matching donors and recipients is crucial to prevent tissue rejection by the immune system. Blood relatives are preferred as organ donors because they are more likely to share genetic similarities, including the MHC (HLA) genes, which play a role in tissue compatibility. Immunosuppression is used in transplantation to suppress the immune system and prevent rejection of the transplanted tissue. Although immunosuppressive therapy can increase the risk of infection and cancer, it is necessary to ensure the success of the transplant.