When facing a serious diagnosis like leukemia, lymphoma or certain blood disorders, you may hear your care team mention a bone marrow transplant, stem cell transplant or even a “blood and marrow transplant.” While these terms are often used interchangeably, there are important differences between them. Yvonne Efebera, MD, MPH, program and medical director for the Blood and Marrow Transplant and Cellular Therapy Program at OhioHealth, helps break down what these procedures mean, when they’re used and how they work.
How bone marrow and stem cell transplants differ
According to Dr. Efebera, the term “BMT” stands for blood and marrow transplant, not bone marrow transplant, though many people refer to it that way out of habit. Both blood and marrow transplants and stem cell transplants involve eliminating non-functioning, deficient bone marrow or cancerous cells and then replacing them with new, healthy hematopoietic stem cells. Hematopoietic stem cells are cells that can grow into all the different types of blood cells your body needs — including red blood cells, white blood cells and platelets.
The main difference between these two transplant types is the source of the stem cell transplant:
- In blood and marrow transplants, the donor stem cells are retrieved through a bone marrow harvest that is performed through a surgical procedure with anesthesia.
- In peripheral blood stem cell transplants, the donor stem cells are retrieved from the peripheral blood, which is collected through a simple outpatient process called apheresis.
With both types of transplants, there is a further distinction between the types of transplants someone can get. The main difference between these is who the donor is:
- Autologous transplant: The patient receives their own stem cells, typically after chemotherapy. Most autologous transplants are peripheral blood stem cell transplants. This is common in cancers like multiple myeloma and some lymphomas.
- Allogeneic transplant: Stem cells come from a donor. This is more common in leukemia, myelodysplastic syndrome (MDS) and aplastic anemia
Stem cells from bone marrow (BMT) — in which donor stem cells are needed (allogeneic transplant) — are often used for children or patients with non-cancerous conditions, because they contain fewer T-cells and reduce the risk of a complication known as graft versus host disease (GVHD). “GVHD occurs when donor cells recognize the patient’s body as foreign and attack it,” notes Dr. Efebera. The skin, liver and gut organs and tissues are the most common involved in GVHD.
Allogeneic transplants (from donors) with the use of peripheral blood stem cells, on the other hand, are more commonly used in adults — especially for blood cancer treatment — because the T-cells they contain may help fight the cancer cells. This immune response after a stem cell or bone marrow transplant wherein the donor’s immune cells recognize and attack the recipient’s leukemia cells is known as the graft-versus-leukemia effect. Autologous transplants, using the patient’s own peripheral blood stem cells, are also more commonly used in adults.
Who might need a transplant?
Bone marrow and stem cell transplants are used to treat:
- Blood cancers, like leukemia, lymphoma and multiple myeloma.
- Non-cancerous blood disorders, like aplastic anemia and certain genetic conditions.
A patient’s need for a transplant depends on disease type, treatment response and genetic risk factors. For example, high-risk leukemia patients may be directed to transplant even during remission to prevent relapse.
Transplants can be either curative or used to extend the period of remission. “In some conditions like multiple myeloma, the goal is to keep the disease in check. In others, like leukemia, we may be aiming for a cure,” says Dr. Efebera.
How the transplant and donor processes work
Facing a transplant can be overwhelming, but Dr. Efebera urges patients not to go it alone. “Bring a support person to appointments. Write down your questions. Talk to others who have gone through it. And don’t be afraid to ask for a second opinion from another provider.”
The preparation for a transplant depends on the type. For autologous transplants, patients typically receive chemotherapy to try to put the disease into remission or ready the body for a good response. Then, their stem cells are collected. Patients then get a high dose chemotherapy followed by an infusion of their stem cells.
For allogeneic transplants, patients must be matched with a donor. Matches are determined by HLA typing — a process that compares antigens on the surface of tissues and cells. If a match isn’t found within the family, the search extends to national and international donor registries.
“A donor doesn’t need to be a family member — as long as their HLA proteins match, they can be a perfect stranger,” says Dr. Efebera. Not all transplants have to be full matches to be successful. However, the closer to a full match the donor is, the less likely complications like GVHD will arise.
Donors can be from anywhere in the world and any gender, though age and health status can play a role. “We typically select donors that are under 40, preferably men or women who have not had children,” Dr. Efebera explains, as these donors are less likely to produce immune reactions.
Transplant medicine has seen major progress. “The five-year survival rate for donor transplants for cancer has improved from 25% to over 50%,” Dr. Efebera shares. Better GVHD prophylaxis, infection prevention and supportive care have significantly reduced complications and improved outcomes.
New options like haploidentical transplants (using half-matched donors, such as a parent or child) have increased access to treatment, especially for underrepresented groups who are less likely to find a full match in donor registries.
Risks and misconceptions
While transplants offer life-extending and sometimes curative benefits, they do carry risks. Common side effects include infections, low blood counts and GVHD. However, innovations in GVHD prophylaxis and supportive care measures are helping minimize those risks.
One common myth is that donating stem cells is akin to donating an organ. “It’s not an organ donation,” Dr. Efebera emphasizes. “When you donate peripheral stem cells, your body recovers within a week. There is no long-term impact on your health. And for peripheral blood donations, it’s an outpatient process and takes about four hours. It’s boring, but it doesn’t require anesthesia.”
Another misconception is about stem cell sources. Some patients mistakenly believe transplants involve embryonic stem cells, which isn’t the case in standard transplant procedures.
The role of donors
The role donors play in the transplant journey can’t be understated. “A donor transplant can be life-changing or even curative, especially for children,” emphasizes Dr. Efebera. “It’s not just medical — it’s about giving someone a second chance. The more people who register to be donors, the more we can offer life-changing therapy to people who really need it.”
The success of allogeneic transplants often depends on having donors that are a good match for the patient. There is a discrepancy in the donor database between donors available for Caucasians versus people of color. “Caucasians have a 70-80% chance of having a match in the donor database while African Americans and Hispanics only have about a 30% chance of having a match in the registry,” says Dr. Efebera.
She goes on to explain that misconceptions, like those already covered, often prevent people from becoming donors. “We need to educate more about what donating actually involves. If you’re African American or Hispanic, it’s even more important to register to be a donor. More diversity in the registry helps everyone.”
Even if you register and are never called, you’re still making a difference by simply being in the system. To learn more or register as a donor, contact the National Marrow Donor Program, formerly known as Be The Match.
