Autologus Bone Marrow Transplantation
Autologous bone marrow transplant is a process of administering High doses of chemotherapy or radiotherapy to eliminate maximum number of cancer cells which cannot be achieved by standard doses of drugs. The drugs or radiation at such high doses kill not only the cancer cells, but also the bone marrow stem cells. Patient’s own marrow stem cells can be used to replenish his/her own marrow after high dose of chemo-radiotherapy. This is called Autologous BMT.
The drugs are chosen in a way that at maximum tolerated dosages, it only hurts the bone marrow permanently and the effect on the rest of the body is either absent or minimum. Even if the effect is severe, it is reversible and short-lasting. For doing so, the hematopoietic cells of the patient are removed before giving high dosage of chemotherapy or radiation treatments. They are frozen and stored. Once the chemotherapy or radiation process gets complete, harvested and stored cells are returned back to the patient’s body.
We currently do not have the capacity to grow a liver or heart or lungs or kidney by infusing a few million cells in our body, but we can do so for the bone marrow.
How are the stem cells collected during the transplant?
- Using peripheral blood STEM cell APHERESIS technique, stem cells are taken from the blood of patient.
- G-CSF being a growth factor is used to stimulate the movement of stem cells from the marrow to the circulating blood.
- This takes around 4 days. On the fifth day, the blood is collected from the patient's vein in a machine called cell separator. In a continuous process, the blood is spun down inside the machine and the required cells are collected in a bag. The entire process might take 3-4 hours.
- However, this does not involve any surgery and the patient sits on a couch or lies in a bed and can comfortably read a book or watch the television.
This process of collecting stem cells is known as “Apheresis”.
Process of stem cell transplantation in autologous transplants
The process starts with the Insertion of central venous catheter (CVC) in the arm or chest of the patient. The high doses of chemotherapy are administered through the CVC. A day or two following this, the frozen stem cells of the patient are revived by immersing them in a water bath. They are immediately infused through the CVC.. The bone marrow stem cells have an uncanny ability to reach their home ie the marrow itself travelling through various organs of the body. Production of new cells starts within 2-3 weeks.
During this period-
Antibiotics and medications are given in order to prevent or treat any infection.
Blood tests are repéated regularly in order to check RBC, WBC and Platelets count.
Transfusions are given to patient until, the infused stem cells start producing platelets and blood cells.
Diseases which can be cured
- Lymphoma –Hodgkin’s and Non-Hodgkin’s
- Acute Myeloid Leukemia- sometimes
- Paediatric solid tumours
- Multiple sclerosis
- Auto-immune diseases not responding to medical treatment
What are the Advantages of Autologous bone marrow transplantation over standard chemotherapy?
In patients suffering from myeloma, for example, the maximum killing of myeloma cells is achieved above the dose of 120 mg/m2 of Melphalan. However, doses above this result in complete and irreversible destruction of bone marrow function, while the effect on other parts of the body are minimal or temporary. This effect on the cancer cells are not achievable with repeated small doses of the same drug.
The same principle is used for curing patients with lymphoma, pediatric solid tumours such as neuroblastoma,ewings sarcoma etc and some selected cases of breast cancers.
Do I Need an Autologous BMT or an Allogeneic BMT
This will be decided by your doctor in discussion with you. In certain diseases, Autologous BMT might be sufficient, whereas in others, where the bone marrow is diseased, marrow from a healthy donor is preferred.
Advantages of Autologous BMT
- Does Not Need a Donor
- Rejection is Rare
- Less Risk Involved
- Shorter Hospital Stay
- Less Risk of Infections in the Long Run
Disadvantages of Autologous BMT
- Higher Chance of Relapse (Return of Original Disease)
Autologous BMT for Autoimmune Diseases
This is an area of growing interest and research. When our own immune system turns rogue and attacks our own body, any organ can be affected starting from Brain (Multiple Sclerosis) to the Kidneys (Lupus) or the Skin (Scleroderma). Medicines often fail to cure or contain these conditions.
The self-destructive immune system can be eliminated by the use of high doses of chemotherapy and other immunosuppressive drugs. The frozen marrow or blood stem cells of patient can be used to rescue the patient from marrow destruction.
When the stem cells are infused back, there are two possibilities. One, the stem cells would wake up to produce more well behaved immune system which shall no longer behave like a truant child. Second, the immune system might again acquire the self-destructive properties in due time.
However, the adoption of Autologous BMT for conditions like Multiple Sclerosis and Scleroderma has often resulted in marked improvement in the life of these patients who were destined to perish in agony.