What would likely happen if a transplantation does not meet matching criteria?

When a transplantation does not meet matching criteria, the likelihood of failure or rejection is significantly increased. Matching criteria typically involve various factors, such as blood type and human leukocyte antigen (HLA) compatibility, which are crucial for the body to accept the transplanted organ or tissue. If these criteria are not adequately met, the recipient's immune system may recognize the transplanted tissue as foreign and mount an immune response against it. This can lead to transplant rejection, where the body actively tries to eliminate the transplanted organ, resulting in complications that may make the procedure unsuccessful. Therefore, the correct answer reflects the reality that without proper matching, the chances of transplant rejection are highly elevated, which is a critical consideration in organ transplantation practices.