Graft failure and graft rejectionThe term graft failure is used to describe inadequate HSC function after transplantion. This is different from graft rejection that may occur when the patient's immune system has not been suppressed sufficiently. Clinically, a distinction is made between "primary graft failure" when no hematopoiesis is observed and "secondary graft failure" when after an initial engraftment, hematopoiesis becomes weaker with time. The latter may still occur several years after transplant. Distinction between graft failure and graft rejection is not always evident. A graft rejection is characterized by a sharp increase of recipient T cells that are responsible for rejection. It is important to distinguish between graft failure and graft rejection because in the case of a rejection, the T cells of the recipient have to be removed by treatment with anti-lymphocyte antibodies before a second transplant can be performed. |