What a Bone Marrow is?
Bone Marrow is the spongy, greyish, fatty tissue found in bones. Stem cell is the most important part of the bone marrow which is responsible for the growth of r blood cells (white blood cells and red blood cells) and also blood platelets. Each of these blood cells has a significant function. The white blood cells, also called leukocytes, help fight infection. The red blood cells, also referred to as erythrocytes, are the carriers of oxygen to all the organs and tissues and they also aid in getting rid of waste material from the body. The blood platelets on the other hand are responsible for clotting of the blood that helps in preventing excessive bleeding.
What is Bone Marrow Transplant?
A Bone Marrow Transplant is a medical procedure of replacing damaged bone marrow with bone marrow stem cells that are healthy and help blood cells to grow. Healthy bone marrow stem cells are filtered and given back to either the same patient or another patient, who is an appropriate genetic match. The first Bone Marrow Transplant was successfully carried out in 1968, making it a relatively new procedure for treatment of certain cancer and solid tumours.
Types of Bone Marrow Transplants
Autologous Bone Marrow Transplant or Rescue Transplant: In this process, the healthy stem cells from a patient are used to replace the diseased stem cells of the same patient before receiving high-dose chemotherapy. In cases where the disease being treated does not affect the bone marrow, e.g. in breast cancer or ovarian cancer, the healthy stem cells are removed from the patient and frozen before the aggressive chemotherapy starts. On completion of the radiation or chemotherapy sessions, the healthy stem cells are re-infused into the same patient’s blood stream where healthy blood cells start to develop.
Allogeneic Bone Marrow Transplant: This type of bone marrow transplant is carried out by using the stem cells of a donor. The donor has to have same genetic match with the concerned patient for a successful bone marrow transplant. There is a 35% chance that a patient will have a sibling with a good genetic match. In some cases, parents or other relatives might act as a suitable match, in the absence of whom, the international bone marrow registries can be referred to for other suitable donors.
Syngeneic Bone Marrow Transplant: When the stem cells are donated by one identical twin to the other for the purpose of bone marrow transplant it is called syngeneic bone marrow transplant. In this case, the genetic match will be almost perfect and therefore will have higher chances of successfully adapting in the patient’s body.
Umbilical Cord Blood Transplant: When a baby is born, the stem cells from its umbilical cord and the placenta are collected and frozen at a bank for use of future transplants. The stem cells are mostly used for children, since the quantity of blood producing cells is limited and might not suffice for adults. This procedure is fairly new and is still gaining strength.
When the donor’s genetic make-up is not close to the patient’s, there is a high risk of graft-versus-host disease. In this case, the grafted stem cells will perceive the patient’s body as a hostile environment and work towards destroying healthy blood cells causing a life threatening situation. In a better situation the patient’s immune system might recognize the grafted cells are foreign and destroy them. This situation is called graft-rejection.
Read more articles on Bone Marrow Transplant.
Prognosis of bone marrow cancer is poor, but drugs like bisphosphonates have been known to reduced the complications.read more
How is Bone Marrow Transplant done: The preparations for a bone marrow transplant vary depending on the type of transplant, the disease requiring transplant, and patient's tolerance for certain medications.read more