Types of Blood and Marrow Transplantation Procedures

There are several different types of blood and marrow transplantation procedures. Select one of the procedures listed below for a brief overview.


Allogeneic Stem Cell Transplant

In an allogeneic transplant stem cells are harvested from another person whose bone marrow is an exact or close match to that of the patient. A transplant using stem cells from umbilical cord blood is also an allogeneic transplant.

Allogeneic transplants are often used in treating patients with blood-based cancers or disorders, leukemia, aplastic anemia, lymphomas, and immune deficiency diseases.

Finding a donor match can be a lengthy process that requires several weeks, months, or longer. Close relatives and other family members are the first people tested for a possible match. Donors may also be identified through the National Marrow Donor Program.

Both the patient and prospective donors must undergo tissue typing to evaluate the human leukocyte antigens (HLA) in their blood. The testing is similar to blood typing, however, in tissue typing, the white blood cells are used to determine a match. During typing, six proteins on the cell's surface are evaluated. If six of six proteins match, it is an exact match. If four or five of the proteins match, the donor can still be used.

Once a suitable donor is confirmed, the patient begins treatment with high-dose chemotherapy, radiation, or a combination of therapies to destroy the cancer cells. These therapies also weaken the immune system, which reduces the chance that the transplanted stem cell will be rejected. Because the immune system is severely compromised, patients must be placed in isolation to protect them from exposure to infection.

Stem cells collected from the donor are administered to the patient about one to three days after chemotherapy is complete. During this time, medication may be used to control the side effects of treatment which can include nausea, vomiting, diarrhea, and pain. Often antibiotics are prescribed to help prevent infection.

Other medication can be used to control a condition called graft-versus-host disease (GVHD). This problem results from subtle differences that exist between the cells of the patient and donor cells. It usually begins two to four weeks after blood and marrow transplantation.

The length of time a patient must stay in the hospital following an allogeneic procedure varies widely. After discharge, daily clinic appointments may be required for a period of time, and recovery from the transplant may take up to a year or more.

Autologous Stem Cell Transplant

In an autologous transplant, the patient donates his or her own stem cells, and then receives them back after intensive chemotherapy or radiation therapy. 

Autologous stem cell transplants are used most often to treat solid tumors, lymphomas, and certain types of leukemia.

A patient who is to have an autologous stem cell transplant may sometimes need chemotherapy to reduce a tumor as much as possible prior to the transplant. After the stem cells are collected from the bone marrow or peripheral blood, they are maintained under extremely cold conditions (cryopreserved) until the patient is ready to receive them back. About one to three days after high-dose chemotherapy and/or radiation therapy, the collected stem cells are reinfused.

As with the allogeneic transplant process, patients whose immune systems have been compromised by the cancer treatment require protective isolation to prevent infection. During this time, medication may be used to control the side effects of treatment, and antibiotics are prescribed to help prevent infection 

Because the patient is also the donor, recovery from an autologous transplant is usually quicker than from a stem cell transplant that requires a donor. Graft-versus-host disease (GVHD), a form of rejection, is also not a factor. 

Recovery from an autologous stem cell transplant usually requires from four to six months.

Syngeneic Stem Cell Transplant

A syngeneic stem cell transplant is the rarest form of stem cell transplant. In this procedure, an identical twin serves as the donor. This type of procedure is most similar to an autologous transplant because the genetic makeup of the twins is exactly the same. Although graft-versus-host disease (GVHD) can occur, the risk is greatly reduced for the same reason.