Blood cells grow in the same way as other human cells. They develop in the bone marrow from a parent cell known as a stem cell. Stem cells are immature cells that can develop into all of the different types of blood cells: white blood cells, red blood cells and platelets. Stem cells are usually found inside the bone marrow spaces of large bones. They can also travel from one bone to another by way of the blood stream.
In a blood and marrow transplant, stem cells are harvested, either from the large bones or from the blood stream, and transplanted to the patient. Stem cells collected from the pelvic bone in the lower back are called bone marrow. Stem cells harvested from the blood in the veins are called peripheral blood progenitor cells. This is why blood and marrow transplants are often referred to as blood stem cell transplants. For simplicity, we will use the terms bone marrow and stem cells interchangeably on this site.
Your BMT doctor will discuss how stem cells will be collected from you or your donor.
How are stem cells collected?
There are two different methods to collect stem cells.
Peripheral Blood Stem Cell Collection. Stem cells can be collected from the blood. This procedure is called a peripheral blood stem cell collection. This technique does not require surgery. It does, however, involve a few more steps than a conventional bone marrow harvest. Prior to the collection, the donor is given a medication to promote the growth and release of stem cells from the bone into the blood. The stem cells are then collected using a special machine called a Cell Separator. This technique has dramatically increased in popularity over the last ten years. Stem cells are generally collected using this method here at the Leukemia/BMT Program of BC.
Bone Marrow Harvest. Stem cells can be collected directly from the bone marrow spaces, most often from the pelvic bones. Several puncture sites are made along the bone and the cells are removed using a needle. This procedure is known as a bone marrow harvest. Note that this technique is used less often here at the Leukemia/BMT Program of BC.