ABSTRACT
Organ transplantation has become an important modality in various types of disorders. Although the types of organ and cell transplantation have expanded (Table 8.1), the major obstacle confronting all organ transplantations continues to be graft rejection. This is where the immune system responds to the transplanted organ as if it was a foreign antigen, thus mounting an immunological attack. Like the response to any antigen, graft rejection is an immunological process where both humoral and cellular responses are required to orchestrate the defense.
