Pediatric Bone Marrow Transplant Facts

July 23, 2025

This page was reviewed under our medical and editorial policy by by Anna Pawlowska, M.D., clinical professor, and Nicole Karras, M.D., associate clinical professor, Department of Pediatrics, City of Hope^® Cancer Center Duarte.

A ​​pediatric bone marrow transplant is a procedure that may be used to treat certain kinds of childhood blood cancers and some other blood disorders. A bone marrow transplant works by replacing the bone marrow cells damaged by disease or invasive treatment for cancer with healthy stem cells.

What Is a Bone Marrow Transplant for Children?

A bone marrow transplant, also called a hematopoietic stem cell transplant (HSCT), is a procedure in which patients receive an infusion of healthy stem cells taken from their own body, from a healthy donor or from umbilical cord blood. The stem cells in a child’s bone marrow play a key role in helping create red blood cells, white blood cells, platelets and other cells that are essential to the immune system. Pediatric blood cancers such as childhood lymphoma and leukemia disrupt this process, stopping the body from creating healthy new cells.

The goal of a pediatric bone marrow transplant is to replace the stem cells damaged by disease or invasive treatment for cancer with healthy stem cells, so that the body can produce new, healthy blood and immune system cells again. An HSCT is often combined with other treatment options, such as ​​chemotherapy or​​ radiation therapy. ​​Pediatric bone marrow transplant procedures are complex, and are therefore performed by childhood blood cancer and HSCT experts.

Sources of Stem Cells for Transplants in Children

Harvesting stem cells is the term used to describe the process of collecting donor stem cells to be transplanted into a patient’s body via infusion. There are several different sources for stem cells for pediatric bone marrow transplant patients.

Bone marrow: The most common way cancer doctors collect donor stem cells is by harvesting them from a donor’s bone marrow. Frequently, bone marrow is taken from the bones in the pelvis — an area that contains a lot of bone marrow. 

Peripheral blood stem cells: Doctors may also collect peripheral blood stem cells (PBSCs) from a donor using a procedure similar to donating blood. When the donor’s blood is taken from their body, the stem cells are separated out and stored. This process of collecting stem cells is safe and simple. If the donor stem cells are harvested from the patient themselves, this is called an autologous HSCT. If they are given by a family member or an unrelated person, it is called an allogeneic HSCT. The main benefit is that, in the case of an autologous HSCT, the patient’s body is much more likely to accept the new stem cells without any complications, since they are collected from their own body.

Another benefit is that bone marrow transplants using PBSCs tend to result in a faster return to normal blood count levels.

Umbilical cord blood: Healthy stem cells may also be collected from the blood in an umbilical cord. One benefit to this method is that it does not require a donor to provide the stem cells directly. Umbilical cord stem cells are also less likely to cause graft-versus-host disease, which is a possible complication of a bone marrow transplant.

Childhood Cancers and Conditions Treated

​​Bone marrow transplant is a potential treatment option for more than 70 types of blood cancer, as well as other, non-malignant disorders. A pediatric HCST is most often recommended for treating childhood cancers and other diseases affecting the blood and bone marrow, such as:

• Acute lymphoblastic leukemia
• Acute myeloid leukemia
• Juvenile myelomonocytic leukemia
• N​on-Hodgkin lymphoma
• Hodgkin lymphoma
• Blastic plasmacytoid dendritic cell neoplasm
• ​​​Chronic myeloid leukemia
• ​​Thalassemia
• Sickle cell disease
• Langerhans cell histiocytosis and hemophagocytic lymphohistiocytosis (HLH)
• Solid tumors, including germ cell tumors and neuroblastoma
• Acquired and inherited bone marrow failure disorders including aplastic anemia, Fanconi anemia, dyskeratosis congenita, Diamond Blackfan anemia, Shwachman-Diamond syndrome and paroxysmal nocturnal hemoglobinuria
• Hemoglobinopathies
• Autoimmune disorders, such as systemic scleroderma
• Metabolic disorders, including adrenoleukodystrophy

Generally speaking, there are two categories of bone marrow transplant, referred to as autologous HSCT and allogeneic HSCT.

Autologous HSCT

An ​autologous bone marrow transplant uses donor stem cells collected from the patient. The healthy stem cells are collected as PBSCs. In most cases, children who are candidates for an autologous HSCT also undergo chemotherapy before stem cells are harvested from their body.

For children with certain types of cancer, doctors may recommend a tandem (or double autologous) bone marrow transplant. This involves collecting donor stem cells once, splitting the donor stem cells into two batches and delivering two infusions several months apart. This may be a more effective treatment for some childhood cancers, such as neuroblastoma, but it may also lead to more complications during recovery.

Allogeneic HSCT

An ​​allogeneic bone marrow transplant uses donor stem cells collected from someone other than the patients themselves.

Allogeneic Transplant Donor Types

Doctors may use several sources to collect donor stem cells for an allogeneic HSCT.

Matched family donor: If a donor and patient have a similar tissue type, an HSCT is more likely to be successful. Collecting stem cells from a close family member, such as a fully matched brother or sister , is one of the best ways to ensure a close match. There is 25% chance that each sibling is a full match.

An unrelated donor with a tissue match: If a patient does not have a close family member who is a suitable donor, doctors may recommend using a bone marrow registry to look for a donor who is a good match for the patient. This is sometimes also called a matched unrelated donor (MUD) registry. One drawback to this option is that it may take longer to find a matching donor.

Mismatched or haploidentical family donor: If the patient doesn’t have a fully matched family donor or a matched unrelated donor, the stem cells can be given by a partially/half matched family member, including parent, sibling or cousin. This is called a ​​haploidentical bone marrow transplant.

Umbilical cord transplant: Some patients may receive donated stem cells from an umbilical cord that has been collected after a baby’s birth. However, there are downsides to an umbilical cord HSCT, including the fact that the donated stem cells may take longer to start creating new, healthy cells in the patient’s body than cells donated by a family member or matched donor.

Graft-Versus-Host Disease (GVHD)

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​Graft-versus-host disease is a relatively common complication that may affect patients who have undergone an allogeneic pediatric bone marrow transplant. GVHD occurs when the donor's cells (the "graft") attack the recipient's body (the "host") because they see the recipient's cells as foreign. This attack can cause a range of symptoms and complications, depending on the type and severity of GVHD. Most often, GVHD begins within 100 days of an HSCT. However, it may occur at any time.

Patients undergoing a bone marrow transplant usually take certain medications before and for several months after the procedure to help lower their GVHD risk. Another key factor in reducing the chances of complications like GVHD is to ensure that a donor and patient are as closely matched as possible.

What Parents Should Know

If you are a parent or family member of a child who may need a bone marrow transplant, you may have questions about how the procedure works and what recovery looks like. Here are some tips on how to manage the process.

Make a list of questions: As your child prepares for a bone marrow transplant, it’s important to get answers to any questions you or your child have. Make a list of questions to take to your appointments and discuss these with the cancer care team.

Get answers to your child’s questions: Let your child ask his or her cancer care team anything. Younger children might want to know whether the procedure hurts, how long it may be until they can go back to school or see their friends, or what to expect during the transplant. Teenagers may also ask about the physical side effects of HSCT, such as hair loss or the impact on sexual health.

Connect with family: Take time to manage other family relationships and your own emotional health, including talking to your partner or spouse, discussing treatment with siblings or younger family members and seeking counseling for yourself or others.

Find support from other HSCT patients or caregivers: A number of programs at City of Hope and beyond connect parents and their children with other families that have gone through a bone marrow transplant. Talking to those who have been through the same process can help answer questions and offer emotional support.

Help your child maintain a sense of normalcy: Encourage your child to play, do schoolwork and talk to friends. This is particularly important for older children and teenagers.

Consider long-term health issues: Many younger children who undergo HSCT experience slower growth or delays in development. This may sometimes be treated with hormone therapy. Girls who undergo HSCT during or after puberty usually become infertile, while many boys who have a transplant before puberty also suffer from infertility. Talk to your child’s doctors about fertility preservation options.