Cell & Developmental Biology
Open Access

Allogeneic Transplantations

Allogeneic stem cell transplantation involves transferring the stem cells from a healthy person (the donor) to the patient’s body after high-intensity chemotherapy or radiation. The donated stem cells can come from either a related or an unrelated donor.   In an allogeneic transplant, stem cells are collected from a matching donor and transplanted into the patient to suppress the disease and restore the patient's immune system. An allogeneic stem cell transplant is different from an autologous stem cell transplant, which uses stem cells from the patient's own body.  Before an allogeneic stem cell transplantation, the patient receives a conditioning regimen of chemotherapy and, sometimes, radiation therapy. This conditioning treatment is given to destroy any remaining cancer cells in the body. This helps weaken the patient’s immune system to help keep the body from rejecting the donated cells after the transplant. It also allows the donor cells to move through the bloodstream to the bone marrow, where the donor cells will begin to grow and produce new blood cells, including red blood cells, platelets and white blood cells. This process is called “engraftment.” When a transplant is successful, the donor stem cells can replace stem cells in the bone marrow. It may also provide the only long-term cure of the patient’s disease. One of the benefits of allogeneic stem cell transplantation is that after the donated cells engraft in the patient, they create a new immune system. The donated cells produce white blood cells that attack any remaining cancer cells in the patient’s body. This is called the “graft-versus-tumor effect.” and it may be even more important than the very intensive conditioning regimen that is administered to destroy the cancer cells. This benefit can only occur in allogeneic stem cell transplantation.