An organ or tissue transplant is one type of allotransplantation. Allotransplantation (allo- from the Greek meaning "other") is the transplantation of cells, tissues, or organs, sourced from a genetically non-identical member of the same species as the recipient. The transplant organ or tissue is called an allograft,allogeneic transplant or homograft. Most human tissue and organ transplants are allografts.
In contrast, a transplant from another species is called a xenograft. A transplanted organ or tissue from a genetically identical donor, i.e., an identical twin, is termed an isograft. Finally, when a tissue is transplanted from one site to another on the same patient, it is termed an autograft
An allogeneic bone marrow transplant involves receiving donor bone marrow or peripheral stem cells. This bone marrow transplant donor is genetically matched and can be related or unrelated to you. An autologous transplant involves receiving your own bone marrow or peripheral stem cells.A syngeneic bone marrow transplant involves receiving your identical twin's bone marrow or peripheral stem cells.