G.4 Terms used in transplantation
Allogeneic transplantation: Refers to the transplantation of cells from a donor to another person, either related (as when from a sibling or parent) or from an unrelated individual. In hematopoietic stem cell transplantation, unrelated donors may be identified from large donor registries as being histocompatible or matched to the transplant recipient at a series of human leukocyte antigens known to mediate transplant rejection. Allogeneic hematopoietic stem cell transplantation carries with it the potential for the donor’s transplanted cells to mount an immune attack against the recipient (graft versus host disease), while solid organ transplant carries the risk of the recipient’s immune system rejecting the allograft. Both clinical settings require the use of immunosuppressive drugs, which in the case of solid organ transplant recipients must be taken lifelong, placing them at risk of infectious complications.
Autologous transplantation: Refers to the transplantation to an animal or human patient of his/her own cells. Because the cells are recognized by the patient’s immune system as “self,” no rejection or immune incompatibility is observed. Consequently, autologous transplantation of cells typically carries fewer risks than allogeneic transplantation. Generation of embryonic stem cells by somatic cell nuclear transfer or derivation of induced pluripotent stem cells by reprogramming offers a potential source of autologous cells for many different transplantation studies, offering the theoretical advantage of immune compatibility.
Homologous use: Refers to intended therapeutic use of cells within their native physiological context, for example, the transplantation of hematopoietic stem cells to regenerate the blood, or the use of adipose tissue to reconstruct a breast.
Non-homologous use: Refers to intended therapeutic use of cells outside their native physiological context, for example, the transplantation of hematopoietic cells or mesenchymal stromal cells into the heart or brain.
Tumorigenicity: The property of cells that describes their potential for forming tumors, or an abnormal growth of cells.