Bone marrow, also known as marrow, is the soft, spongy fatty tissue inside the bones. The bone marrow is the medium for development and storage of most of the body’s blood cells. Stem cells are immature cells in the bone marrow that give rise to all of the different blood cells.
It is the stem cells that are needed in bone marrow transplant.
What is bone marrow transplant (BMT)?
A bone marrow transplant is a procedure performed to replace damaged or destroyed bone marrow stem cells with healthy bone marrow stem cells. The procedure involves extracting the healthy stem cells, filtering those cells, and giving them back, either to the donor himself, or to another person(the recipient). The goal of BMT is to transfuse healthy stem cells into a person, after his or her own unhealthy bone marrow has been treated to kill the abnormal cells.
Why is bone marrow transplant needed?
The goal of a bone marrow transplant is to cure many diseases and types of cancer. Bone marrow transplants may also be needed if the bone marrow has been destroyed by a disease. For some diseases, transplant offers the only potential cure.
A bone marrow transplant can be used to:
Replace diseased bone marrow with healthy, functioning marrow.
Treat a disease that affects the production of bone marrow cells or severe immune system illness.
Regenerate a new immune system that will fight existing or residual leukemia or other cancers not killed by the chemotherapy or radiation used in the transplant.
Replace the bone marrow and restore its normal function after high doses of chemotherapy and/or radiation are given to treat a malignancy. This process is often called rescue (for diseases such as lymphoma and neuroblastoma).
Replace bone marrow with genetically healthy functioning bone marrow to prevent further damage.
The risks and benefits must be weighed in a thorough discussion with the doctors and the specialists in bone marrow transplants, prior to the procedure.
Types of bone marrow transplants :
What are the different types of bone marrow transplants?
There are different types of bone marrow transplants depending on who the donor is. The different types of BMT include the following:
Autologous bone marrow transplant:
It is defined as “taken from an individual’s own cells”, where the patient has donated stem cells to be used for their own transplant.
Allogeneic bone marrow transplant:
The donor has been selected based on their HLA type (genetic match) and that of the patient. Stem cells are then taken from an HLA matched donor.
Siblings (Matched related donor/ MRD)
Brothers/sisters are the best choice as donors, provided that their HLA type matches with that of the recipient.
Parent/Children (Haploidentical stem cell transplant):
A haploid-identical match is when the donor is a parent and the genetic match is at least half identical to the recipient's.
Unrelated bone marrow transplants (UBMT) or matched unrelated donor (MUD):
The HLA matched marrow or stem cells are from an unrelated donor, who has been found through bone marrow registries.
Umbilical cord blood transplant:
Stem cells are taken from an umbilical cord immediately after delivery of an infant. The stem cells are tested, typed, counted, and frozen until they are needed for a transplant.
Diseases that can be treated :
Malignant disease :
Relapsed Hodgkins Disease
Relapsed Non Hodgkins Lymphoma (NHL)
Relapsed Ewings Sarcoma
Metastatic Ewings Sarcoma
Metastatic Germ cell tumors
Medulloblastoma, other brain tumors
Other solid malignancy
High Risk ALL
Relapsed or Refractory AML/ALL
Myeloproliferative Neoplasms (MPN)
Non-Malignant disease :
Severe Autoimmune Diseases
Severe Immunodeficiency disorders
Inherited Metabolic disorders
Bone Marrow Transplant Donors :
For an Allogeneic Transplant, a suitable (HLA matched) donor is a must requirement.
What is HLA typing?
Human leukocyte antigen (HLA) typing is used to match a suitable donor for bone marrow transplant.
The best transplant outcome is obtained when a patient’s HLA and the donor’s HLA closely match.
Who can be the ideal donor?
The best possible chance to get the HLA typing match is from siblings. In about 30% of the cases the patient will get a good match from their sisters / brothers. So siblings are the first one to check for HLA match.
If the patient is not getting suitable HLA match with their siblings then the next possibility is the half matched HLA from their parents or children. Half of the HLA markers come from the mother and half from father. It is unlikely that other family members HLA will match the patient.
How to find donor outside the family member?
If the patient does not have suitable match in the family, then transplant team may look for an unrelated donor. In this case stem cell has to be procured from domestic/ international registry.
HCG – The Specialist in Cancer Care is tied up with all national and International Bone marrow registry to perform quick search for the suitable donor.
Typically it takes 2 working days to find out whether any suitable donor match is available in the donor registry or not.
Is there any cost involved in preliminary Donor search from the registry?
No, there is no charge involved for a preliminary donor search. If a suitable donor is found, only then the patient has to borne the cost for Stem cell procurement which has to be paid to the donor registry.
What are the kind of preparation required for the donor?
Once the potential donor is identified then he or she will undergo several tests. Tests related to his or her health will be done to determine the extent of the match.
Once a match for a patient needing a bone marrow transplant is found, then stem cells will be collected either by a bone marrow harvest (collection of stem cells with a needle placed into the soft center of the bone marrow) or peripheral blood stem cell collection (stem cells are collected from the circulating cells in the blood). Of the two, peripheral blood stem cell donations are now more common 95%, which is painless.
Donor has to take growth factor injection 2-5 days before his stem cell donation. Donor has to admitted and hospitalised for 1 -3 days.
FAQ’s about BMT:
Does the donor have to be of the same blood group as the patient?
No! There are 6-10 major markers in the DNA (HLA Typing) that need to match up perfectly in order to consider a match. In fact the donor does not need to have the same blood type at all and even not a full HLA match is require (Haplo Transplant)
Are pieces of bone are removed during this process?
Marrow donors only give through PBSC donation where your blood is removed via an IV and passed through a machine that separates the stem cell. Remaining blood components given back to donor at the same time. No bones or pieces of bone are removed.
Are stem cell donations done via surgery?
Approximately 90% donations are made via nonsurgical technique doctors call PBSC, for peripheral blood stem cell donation. In this technique, blood- forming cells are removed from the donor’s blood via a needle stuck in arm.
Is donation bad for the donor's health?
Every medical procedure involves some risk, and bone marrow donation is no exception. But no more than five percent of the donor's marrow is harvested which does not cause any problems. The cells replace themselves within four to six weeks.