A bone marrow transplant is a procedure for replacing the patient’s blood-forming stem cells with healthy blood forming stem cells from a donor.
Allogenic Stem cell transplantation
In an allogeneic transplant the patient receives stem cells from a donor. The donor may be the patient’s sister, brother, or sometimes a person not related to the patient.
- Allogeneic transplantation success depends to a large extent on how well the human leukocyte antigens (HLA) of the donor’s bone marrow match the HLA of the patient’s marrow. The higher the number of matching HLA, the greater the chance of success. HLA is identified by a special blood test.
- Close relatives (especially brothers and sisters) usually have a greater chance of having HLA-matched bone marrow than unrelated donors.
The process in a nutshell
- Chemotherapy– High-dose chemotherapy and/or radiation therapy is given to the patient.
- Collection– stem cells are collected from the donor’s blood.
- Infusion– donor’s stem cells are infused into the patient’s bloodstream.
- Engraftment and recovery– the transplanted stem cells make their way to the bone marrow and begin producing replacement blood cells.
1. Patient undergoes High-dose chemo and/or radiation therapy
5- 10 days of high-dose chemo and/or radiotherapy to destroy cancer cells ann the patients own stem cells. Common side effects of high-dose chemotherapy include:
- Nausea, vomiting, and diarrhoea
- Loss of hair
- Skin rash, mouth sores
2. Donor’s stem cells are collected from donor’s blood
A process called apheresis is used to harvest peripheral blood stem cells for transplantation.
For 4 or 5 days before apheresis the donor will be given a daily injection of Colony Stimulating Factor (CSF) to increase the number of stem cells in their bone marrow which will cause the stems cells to spill out into their bloodstream where they can be easily harvested .
The donor’s blood is collected in a process similar to giving a normal blood donation. No general anaesthesia is required and the procedure is usually done over a period of around 4 hours on an outpatient basis.
During the collection process the donor’s blood is processed and the stem cells are concentrated and prepared for infusion into the patient. The parts of the donor’s blood not required for the transplant are returned to the donor during the apheresis process.
3. Infusion of stem cells into the patient
After the patient’s course of high-dose chemotherapy/radiotherapy is completed, the donor’s blood forming stem cells are injected into the patient’s bloodstream through a catheter. Infusion of stem cells usually takes 2 to 4 hours.
Common side effects of stem cell transplant include:
- Nausea, vomiting, and cramping
- Unusual odour, taste of garlic
4. Engraftment and recovery
During the process called engraftment, the transplanted stem cells make their way to the bone marrow and begin producing replacement blood cells. This process lasts for several weeks
Shortly after the stem cell infusion, the patient will begin daily injections of colony-stimulating factor (CSF) to stimulate the production of blood cells by the donated stem cells in the patient’s bone marrow, thereby shortening the time necessary for the stem cell transplant to engraft.
Patients will be required to report for frequent check-ups and tests. Outpatients will need to stay close to the hospital during recovery. Some patients will be admitted to the hospital during recovery
Patients are very susceptible to developing infections until the engraftment process is completed. Even common colds can cause serious problems for the body’s weakened immune system. Preventing infections is a high priority during the engraftment and recovery process.
Treatment and precautions during the engraftment and recovery phase
- Patients may have transfusions of red blood cells and platelets to prevent anaemia and bleeding
- Patients often receive antibiotics to help prevent infection
- Visitors are usually asked to wear masks and gloves
- Flowers, fresh fruit, and fresh vegetables may be prohibited from the patient’s room
- Patients must avoid small children, pets, and people who are ill
- If infection and fever occur, patients may receive antibiotics in the hospital
- A complication called graft-versus-host disease sometimes occurs with allogeneic stem cell transplantation. The donor’s white blood cells (the graft) attack the cells of the patient’s body (the host) because they identify the patient’s body as foreign. Graft Versus Host Disease can be treated with steroids or other immunosuppressive agents.
Information and diagrams sourced from Leukine.com, editing by JRSH, formatting by LHH