Stem cell transplant
Allogeneic stem cell transplant is considered the best treatment for younger people with aplastic anemia. In this type of transplant, you receive stem cells (from the bone marrow or blood) from another person (donor). This type of transplant works best in children and young adults. As people get older, it’s harder for them to tolerate this procedure. For people older than 30 or 40, many doctors prefer using immune therapy as the first treatment. In order for transplant to be an option, you need to have a donor who is matched to you. Someone who is closely related to you, like a brother or sister, is generally the best choice. In aplastic anemia, this stem cell transplant is successful up to 80% to 90% of the time if cells from a matched related donor are used.
Matching is determined by a type of test called HLA typing, which is done in the laboratory. If there is no match from a brother or sister, sometimes an unrelated donor will match. A transplant from a matched-unrelated donor is riskier than using a sibling match. Another option is to use stem cells from the umbilical cord of a newborn baby. A nationwide registry of potential stem cell donors and stored umbilical cord blood has been developed (www.marrow.org). Many doctors recommend using a non-related donor only if immune treatments described below don’t work.
For a stem cell transplant, you will first receive chemotherapy (chemo). The chemo drugs used most often include cyclophosphamide (Cytoxan®) and fludarabine (Fludara®). A drug to suppress your immune system, like anti-thymocyte globulin (ATG) or alemtuzumab (Campath®), is also given. A newer drug, daclizumab (Zenapax®), may also be used. This immune treatment is important to keep your immune system from killing the new bone marrow (like it killed your original bone marrow). Immune treatment is also important to prevent the new bone marrow from attacking your body (this is called graft-versus-host disease and is discussed later in this section). You may also get a low dose of radiation therapy to your whole body. People with inherited forms of aplastic anemia are very sensitive to chemotherapy and radiation, and so often receive lower doses.
Soon after the radiation and/or chemotherapy, you will receive a transfusion with blood-forming stem cells from a donor. The stem cells can be obtained from the donor by removing bone marrow in the operating room while he or she is under general anesthesia. Sometimes a procedure called apheresis is used to remove stem cells from the bloodstream. Apheresis uses a machine that is hooked up to a large vein (through a catheter) and removes stem cells from the blood (returning the other cells). No matter which way they are collected, the stem cells are infused through your vein into the blood and then travel to the bone marrow, where they will grow.
Stem cell transplantation is a major procedure with many risks and side effects. Some people may die during this procedure. The most serious side effects often occur during the first few weeks after the transplant. But with advances in this treatment, death from these early side effects is less common. The chance of severe side effects increases with the age of the patient.
In the first few weeks after the transplant there are usually side effects from the chemotherapy or radiation therapy. You may develop nausea, vomiting, diarrhea, and mouth sores from the treatment. Very low blood counts requiring red blood cell and platelet transfusions are common. Low white blood cell counts can lead to serious infections that require treatment with intravenous (IV) antibiotics. All of these problems generally go away in 3 to 4 weeks when the transplanted blood-forming stem cells start to produce normal blood cells.
If ATG is used, there is also a risk of serious allergic reactions during the infusion. These reactions can range from skin rashes to low blood pressure and problems breathing. Generally, these side effects can be controlled with medicines. This is discussed in more detail in the next section.
A very serious side effect of a stem cell transplant is graft-versus-host disease (GVHD). This occurs when the transplanted donor cells attack your own cells through an immune reaction. GVHD is more common with unrelated or mismatched donors. The risk of GVHD is also higher in older patients. GVHD can occur very early after the transplant. This is called acute GVHD. When GVHD develops later on or lasts a long time it is called chronic GVHD. Early signs of GVHD include skin rashes with severe itching and bowel disturbances such as diarrhea. There may be abnormal lab tests showing liver damage. GVHD is treated with medications (like prednisone, methotrexate, or tacrolimus) to try to suppress the immune system. In some cases, GVHD goes away and the medications can be stopped. In other cases, GVHD is only partly controlled, and medications are needed for a long time. GVHD can sometimes be very disabling and occasionally even cause death.
For more information, please see our document Stem Cell Transplant (Peripheral Blood, Bone Marrow, and Cord Blood Transplants.
Last Medical Review: 04/23/2013
Last Revised: 04/23/2013