Current Environment:

What is a stem cell transplant?

A stem cell transplant (also called bone marrow transplant) is the infusion of healthy stem cells into the body to stimulate new bone marrow growth. Stem cells are vital to a person’s ability to fight infection. Stem cell transplants are performed on children whose stem cells have been damaged by disease or invasive treatments for cancer such as chemotherapy and/or radiation therapy. There are two types of stem cell transplant:

  • Autologous transplants, in which the patient’s own stem cells are collected, stored at a special laboratory, and reintroduced into the patient’s system intravenously.
  • Allogeneic transplants, in which stem cells are collected from a tissue-matched donor (a sibling, an unrelated donor, or umbilical cord blood) and delivered intravenously. Learn how we can help find a stem cell donor.

We perform both autologous and allogeneic stem cell transplants to treat a range of cancerous and non-cancerous conditions. Learn about conditions treated by stem cell transplants.

Stem Cell Transplant | What to Expect

Stem cell transplantation (bone marrow transplantation) is a complex process that may take months to complete. Your doctors, nurses, and the transplant patient coordinator will review information about your child's stem cell transplant during the consent meeting, daily rounds, and visits to the Jimmy Fund Clinic. A general description of the stem cell transplantation process follows.

Pre-transplant appointments

Children eligible for stem cell transplantation will have several preliminary appointments, including tests and blood work, scheduled before being admitted for transplant. These pre-transplant evaluations and appointments will be scheduled by our Stem Cell Transplant patient coordinator, who acts as your liaison to the clinical team. You will also meet with a senior member of the transplant team to discuss the plan for your child in depth and to sign the transplant consent form.

If your child is receiving an autologous (self) peripheral blood stem cell transplant, we will collect his/her stem cells before admitting your child for transplant. Stem cells are collected at the Apheresis Therapeutic Unit at Boston Children's Hospital. Stem cell collection is coordinated with your care provider and the Stem Cell Transplant patient coordinator.


Patients are admitted to 6 West, the stem cell transplantation unit at Children's. Your child may be admitted in one of three ways:

  • From the Jimmy Fund Clinic
  • Through admitting at Children's
  • After a surgical procedure, such as a new central venous line (CVL), at Children's
  • The Stem Cell Transplant Patient Coordinator will arrange your child's admission.

Conditioning therapy

Conditioning therapy refers to the high-dose chemotherapy and/or radiation that children receive before their stem cell infusion. The day your child receives the bone marrow or stem cells is called Day Zero (Day 0). The days prior to Day 0 are the days that a patient receives the conditioning therapy. These days are referred to with negative numbers, for example Day -7, Day -6 or Day -5. There are several goals of conditioning therapy:

  • To kill cancer cells in the body in patients with a malignant disorder
  • To kill the normal cells in the marrow cavities of the bones so the new marrow will have room to grow

If your child is receiving cells from another person, conditioning therapy has a third goal: to suppress your child's immune system so it will not reject the donor's cells.

Day 0: Stem cell infusion

Day 0 is the day the stem cells are infused. Stem cells are infused through the child's central venous line.

Expected side effects

After Day 0, the days are referred to with positive numbers, for example Day +1, Day +2 or Day +3. Patients may begin to have some of the expected side effects of the conditioning therapy such as nausea, vomiting, diarrhea, and mouth sores.

Infections after transplant

Stem cell transplantation patients are at high risk for infections because the immune system is suppressed from the conditioning therapy. Patients who receive stem cells from another person have an additional risk for infection since they take medications that suppress the new immune system. Patients need these immunosuppressive medicines in order to help prevent graft-versus-host disease (GVHD).


After the marrow has been infused, the number of white blood cells and neutrophils, a certain type of white blood cell, increase over the next two to four weeks. Engraftment occurs when the stem cell graft is making enough neutrophils to offer some protection against bacterial infections.

Graft-versus-host disease

If your child receives stem cells from someone else, there is a risk of graft-versus-host disease (GVHD). GVHD may occur before or after stem cell engraftment. It is caused when the donor's (graft) T lymphocytes, a type of white blood cell, react against the cells of the patient (host). Therefore, the condition is called graft (donor)-versus-host (patient) disease. The patient is most likely to show the effects of GVHD in the skin, the gastrointestinal tract (digestive system), and the liver. In general, acute GVHD occurs before Day +100 and chronic GVHD occurs after Day +100.

Other side effects

The conditioning therapy and medications used during transplant may cause other side effects and toxicities, which will be discussed during your initial consent meeting. Our doctors and nurses will explain these problems, and the recommended treatments, if they occur. Blood tests, X-rays, CT scans, MRI scans, ultrasounds, or biopsies (tissue samples) of certain tissues may help in the diagnosis of such problems.


A child may be discharged after engraftment has occurred. He or she must also be medically stable and able to take the required medications.

Restrictions after discharge

Autologous (self) transplant patients should not attend school or visit other public indoor places for six months after transplant. Allogeneic (related and unrelated donor) transplant patients should not attend school or visit indoor public places for nine to 12 months after transplant, depending on the patient's status. We will provide you and your family with educational materials upon discharge that review common post-transplant issues.

Stem Cell Transplant | Finding a Stem Cell Donor

If your child needs stem cells from someone else, we will determine the best donor possible using HLA typing. HLA typing is the process of determining each person's transplant antigens. Antigens are "fingerprints" on the surface of almost all cells of the body.

The typing process has two steps. The first is called serological typing, which provides a broad definition of your tissue type. The second step, which is more refined and specific, is performed using a DNA method. Although no two people have exactly the same antigens on all of their cells (except for identical twins), it is helpful to find a donor whose HLA type is as similar as possible to the patient's HLA type. We will begin by drawing blood from and HLA typing the patient and the immediate family members.

Matched or closely matched family donor

About 25 out of 100 patients have a family member who is a match at the six major sites tested. If a family member matches in five or six of the areas, he or she may be selected as a donor. If more than one family member matches, our transplant specialists will choose the most appropriate donor using blood tests and clinical information.

Unrelated donor

If no acceptable match is found within the family, the transplant team may conduct a preliminary search for an unrelated donor through the National Marrow Donor Program (NMDP) and more than 46 international and cord bank computerized database registries. The preliminary search is free.

The transplant team will ask the registries to contact potential matched donors for further testing. This is a formal search and this requires insurance coverage or a financial down-payment. The transplant team meets at least weekly to review the status of the donor search, and the Stem Cell Transplant Patient Coordinator will update the patient and family on a regular basis.

Mismatched family and haploidentical transplant

Some patients will not have an acceptable donor in the registries. There are research studies where family members may be used as a donor even if they are not a close enough match for a traditional transplant. This type of transplant is called a haploidentical transplant.

Any family member between the ages of 17 and 60 who has been HLA tested at Dana-Farber Cancer Institute may enroll in the NMDP by contacting the NMDP Donor Center at 617-632-2561. All family and friends also are encouraged to consider enrolling in the Platelet Pheresis Program at Dana-Farber, Boston Children's Hospital, or another cancer center. This program will enroll individuals into the NMDP free of charge after donating platelets three times.

Stem Cell Transplant | Programs & Services