Aplastic Anemia: Bone Marrow Program Overview
Aplastic anemia is a rare but extremely serious disorder that results from the unexplained failure of the bone marrow to produce blood cells. Failure of the bone marrow cell production can result from damage to the stem cells or to the environment. The result is aplastic anemia.
The diagnosis of aplastic anemia begins with a blood test. Blood cell levels are normally maintained within certain ranges. The diagnosis of aplastic anemia is suspected when all three blood cell levels are very low.
When the bone marrow cell production fails, normal blood levels of red cells, white cells and platelets begin to fall. Symptoms occur when blood cell levels fall to dangerously low levels.
Aplastic anemia is a medical emergency. Patients with severe aplastic anemia require immediate hospital treatment.
- Blood transfusion Aplastic anemia patients are often given transfusions. Anemia is corrected by red cell transfusions. Since anemia in itself is not an emergency, red cell transfusions are usually given only when emergency which should be treated with platelet transfusions to prevent fatal hemorrhage.
- Antibiotics Because of their extremely short life span, white cells cannot be effectively replaced by a transfusion. Therefore, control of infection depends on prompt, appropriate intravenous antibiotic therapy as soon as fever or other signs of infection appear.
- Isolation To prevent transfer of infection to aplastic anemia patients, they must often be isolated from even healthy people ("reverse quarantine"). Necessary visitors may have to wear masks and gown and must always thoroughly wash hands before touching the patient.
- Activity Activity must be restricted to reduce symptoms of anemia, avoid falls or accidents that could provoke bleeding,and reduce contact with other people.
Bone Marrow Transplantation
Bone marrow transplantation is now being used more and more frequently for aplastic anemia patients who are good candidates and who have a matched donor. Identical twins or perfectly matched siblings are the best choices for bone marrow donors for patients. If a patient does not have a perfect match within the family, a search of existing bone marrow registries may be undertaken to find a matched, unrelated donor.
For young patients in relatively good health prior to transplant, and who have a matched donor, more than half are successfully cured by bone marrow transplantation. For patients who do not have a matched donor, who are over 40 years of age or who are not good candidates for bone marrow transplantation, other forms of therapy are being used.
Doctors may recommend that the patient start on drug therapy while searching for a donor, or drug therapy may be the best choice for treatment for that patient. New therapies are being developed all the time.
Immunosuppressive therapies work with a patient's immune system. One theory about aplastic anemias that the patient's immune system is fighting against itself, thereby interfering with production of blood cells. These drugs are believed to work by stimulating the bone marrow to produce cells or by reducing the patient's immune response and thereby allowing the bone marrow to work.
- antithymocyte globulin
- antilymphocyte globulin
Antithymocyte globulin (ATG) and antilymphocyte globulin (ALG) are immunosuppressive therapies that have been used for treating aplastic anemia. Another immunosuppressive drug is cyclosporin, which may be given alone or in combination with androgens, antilymphocyte globulin or serum. It is thought that cyclosporin plus androgens may stimulate blood cell production.
Hematopoietic growth factors are products of the new genetic engineering. These are copies of substances which occur naturally in the human body, but produced in larger quantities in the laboratory Colony stimulating factors (CSFs) act to stimulate colonies of cells, such as red cells. Interleukin-3 (IL-3) stimulates production of other cells. It is thought that a combination of the growth factors might work in treating aplastic anemia.