Cord Blood Transplants and Leukemia
Stem cell research is continuously expanding, representing a relatively new field of medical technology. Nonetheless, one of the earliest applications of stem cell transplants for the treatment of diseases has been in patients with leukemia. Indeed, stem cell transplants - including both bone marrow as well as cord blood donations - remain the only treatment option for certain types of cancer.
What is Leukemia?
Leukemia is a form of cancer that develops in the bone marrow, a jelly-like substance that is found within the bones. Bone marrow is the tissue in the body responsible for the production of blood cells.
Bone marrow makes three types of blood cells: red blood cells (erythrocytes), platelets (thrombocytes), and white blood cells (leukocytes). White blood cells are responsible for fighting infections in the body, and it is these cells that are affected in patients with leukemia.
In leukemia, immature white blood cells known as lymphoblasts cannot be controlled by the normal mechanisms responsible for maturation. As a result, these cells remain young and continue to multiply instead of developing their normal, mature functions.
Types of Leukemia
Leukemia can affect any of the three main types of white blood cells: Neutrophils (which consume bacteria), Lymphocytes (which create substances that fight off bacteria), and Monocytes (which are responsible for destroying foreign material).
The major types of leukemia are:
- acute myelogenous leukemia (AML), also known as acute granulocytic leukemia
- acute lymphocytic leukemia (ALL), also known as "childhood leukemia"
- chronic lymphocytic leukemia (CLL)
- chronic myelogenous leukemia (CML)
Stem Cells and Leukemia
Leukemia treatment differs from treatment of other types of cancer, since the source of the problem lies in the bone marrow instead of a solid tumor which can be surgically removed. In these cases, bone marrow itself cannot be removed from the patient, since the bone marrow is responsible for the production of blood cells other than white blood cells.
Among the various treatment options available to leukemia patients are stem cell transplants, which are often accompanied by radiation therapy and chemotherapy. The type of stem cell transplant that is used depends on the source of stem cells, which include bone marrow, peripheral blood, or cord blood.
Cord Blood and Leukemia
Cord blood transplants have been successfully used in children with leukemia, and in many cases has the added benefit of shorter recovery periods. Use of umbilical cord blood has also been linked with a reduced risk of developing complications as a result of stem cell transplant, such as GVHD.
Stem cell research is ongoing when it comes to cord blood transplants for adults, the main obstacle being the amount of stem cells found in cord blood units relative to the patient's size. However, a 2004 study found that while a complete bone marrow donor match provided the best outcomes in adult leukemia patients, cord blood transplants offered similar results to incomplete matches of bone marrow transplants.
According to the American Cancer Society, up to 16,000 leukemia patients who require a stem cell transplant each year are unable to find a bone marrow donor match. In these cases, cord blood offers a potential "last resort" for patients who require stem cell transplants.