A team of professionals from LHSC’s Verspeeten Family Cancer Centre who will work with you during the allogeneic stem cell transplant (Allo SCT) process of planning, treatment and follow-up care.
Members of the Blood and Marrow Transplant Program will meet with you and your family to review this information and will be available to answer your questions.
What Are Stem Cells?
Stem cells are found in your bone marrow (spongy tissue inside your bones). Stem cells can form different types of blood cells, like:
- Red blood cells (erythrocytes) - carry oxygen to the body tissues
- White blood cells (leukocytes) - help the body fight infection
- Platelets – help prevent bleeding by making blood clot
- More stem cells
What are allogeneic stem cells?
Allogeneic stem cells are healthy stem cells from another person. This person is considered your donor. It can be someone related to you like a sister or brother, or someone else in the world who has volunteered to be an unrelated stem cell donor.
The donor must have stem cells that “match” you. Your blood will be tested to detect your HLA (Human Leukocyte Antigen) types. HLAs are proteins (or “markers”) found on most of your cells. You get half of these markers from your mother and half from your father.
When you and your donor share the same HLA markers, you are a “match”.
What is an Allogeneic Stem Cell Transplant?
Allogeneic stem cell transplant is a medical procedure used to treat people who have certain cancers, such as leukemia, myelodysplastic syndrome and some types of lymphoma. Transplant may also be used for other non-cancer diseases such as aplastic anemia and sickle cell disease.
Sometimes blood stem cells in bone marrow malfunction and begin producing too many defective or immature blood cells. The abnormal cells are cancer cells that can interfere with the production of normal blood cells and may invade other tissues.
Alternatively, the blood stem cells may produce too few blood cells. When either of these events occurs, a stem cell transplant may be the recommended treatment.
The main transplant steps are:
- High Dose Chemotherapy. A high dose of chemotherapy (with or without total body irradiation) is given to destroy as much of your cancer as possible and make room for the new stem cells. This treatment will also destroy your bone marrow, where blood cells are made.
- Stem Cell Infusion. Since you cannot live without blood cells, the high dose chemotherapy and radiation must be followed by an infusion of donor stem cells through an intravenous line (also known as IV).
- Immune Suppression. These medications are given to help the donor stem cells 'engraft’ (get fixed and grow) in their new home. They are also given to stop the donor stem cells from being rejected (called graft failure) or rejecting you (called graft versus host disease).
The infusion of the donor stem cells is called an allogeneic stem cell transplant. This will allow your bone marrow to grow back and start making healthy new blood cells.
What is the difference between a peripheral blood stem cell transplant and a bone marrow transplant?
A peripheral blood stem cell transplant is different from a bone marrow transplant in the method used to collect the stem cells. The stem cells are the immature cells in the blood and bone marrow from which all mature blood cells develop. When doctors harvest bone marrow for use in a transplant, it is the stem cells they are collecting.
In a bone marrow transplant the stem cells are collected directly from the bone marrow through a bone marrow harvest.
Peripheral stem cells are collected from the blood stream using a machine to separate the cells needed from the rest of the blood. This procedure is called apheresis. One of the advantages of this type of transplant is that recovery from the transplant is usually faster. Peripheral blood stem cell transplants are now more common than bone marrow transplants.
To collect peripheral blood stem cells, the donor must receive a drug called filgrastim, or G-CSF, which boosts stem cell division and helps push the stem cells out of the bone marrow and into the bloodstream for collection.
If you do not have a related donor match, you may be eligible to receive matched donor stem cells from the unrelated donor registry. This process is regulated by the World Marrow Donor Association and made possible through London Health Sciences Centre’s collaboration with the Canadian Blood Services Stem Cell Registry.
All unrelated donors must meet rigorous health evaluation, infectious disease and HLA testing standards to be eligible for donation. For more information on unrelated stem cell donation, visit the How stem cell donation works webpage.
