Bone marrow is soft, spongy tissue within some bones, including those in the hips and thighs. People with certain blood-related conditions benefit from a transplant that replaces damaged cells with healthy cells, possibly from a donor.
This type of transplant can be an intensive procedure, and recovery can take a long time.
Here, we provide an overview of bone marrow transplants, including their uses, risks, and recovery.
Bone marrow contains stem cells. In healthy people, stem cells in bone marrow help create:
- red blood cells, which carry oxygen throughout the body
- white blood cells, which help fight off infection
- platelets, which create clots to prevent excessive bleeding
If a medical condition — such as one that damages the blood or immune system — prevents the body from creating healthy blood cells, a person may need a bone marrow transplant.
A person with any of the following conditions may be a candidate for a bone marrow transplant:
- blood cancers, such as lymphoma or leukemia
- immune or genetic diseases, such as sickle cell disease or thalassemia
- bone marrow diseases, such as aplastic anemia
- bone marrow damage due to chemotherapy or radiation therapy for cancer
There are three types of bone marrow transplant, based on where the healthy bone marrow cells come from.
In many cases, the donor is a close family member, such as a sibling or parent. The medical name for this is an allogenic transplant.
Transplants are more likely to be effective if the donated stem cells have a similar genetic makeup to the person's own stem cells.
If a close family member is not available, the doctor will search a registry of donors to find the closest match. While an exact match is best, advances in transplant procedures are making it possible to use donors who are not an exact match.
In a procedure called an autologous transplant, the doctor will take healthy blood stem cells from the person being treated and replace these cells later, after removing any damaged cells in the sample.
In an umbilical cord transplant, also called a cord transplant, doctors use immature stem cells from the umbilical cord following a baby's birth. Unlike cells from an adult donor, the cells from an umbilical cord do not need to be as close a genetic match.
Before a bone marrow transplant, the doctor will run tests to determine the best type of procedure. They will then locate an appropriate donor, if necessary.
If they can use the person's own cells, they will collect the cells in advance and store them safely in a freezer until the transplant.
The person will then undergo other treatment, which may involve chemotherapy, radiation, or a combination of the two.
These procedures typically destroy bone marrow cells as well as cancer cells. Chemotherapy and radiation also suppress the immune system, helping to prevent it from rejecting a bone marrow transplant.
While preparing for the transplant, the person may need to stay in the hospital for 1–2 weeks. During this time, a healthcare professional will insert a small tube into one of the person's larger veins.
Through the tube, the person will receive medication that destroys any abnormal stem cells and weakens the immune system to prevent it from rejecting the healthy transplanted cells.
Before entering the hospital, it is a good idea to arrange:
- medical leave from work or school
- care for any children or pets
- travel to and from the hospital
- necessities, such as clothes
- lodging near the hospital for family members, if necessary
A bone marrow transplant is not surgery. It is similar to a blood transfusion.
If a donor is involved, they will provide the stem cells well in advance of the procedure. If the transplant involves the person's own cells, the healthcare facility will keep the cells in storage.
The transplant typically takes place in several sessions over several days. Staggering the introduction of cells in this way gives them the best chance of integrating with the body.
The healthcare team may also use the tube to introduce liquids such as blood, nutrients, and medications to help fight infection or encourage the growth of bone marrow. The combination depends on the body's response to treatment.
The procedure will temporarily compromise the person's immune system, making them very susceptible to infection. Most hospitals have a dedicated, isolated space for people undergoing bone marrow transplants to help reduce their risk of infection.
After the last session, the doctor will continue to check the blood each day to determine how well the transplant has worked. They will test whether new cells are beginning to grow in bone marrow.
If a person's white blood cell count starts to rise, it indicates that the body is starting to create its own blood, indicating that the transplant has been successful.
The amount of time that it takes for the body to recover depends on:
- the type of transplant
- how well the immune system recovers
- how well the body accepts the new, healthy cells
Many other factors can affect recovery, including:
- underlying medical conditions
- the use of chemotherapy, radiation, or both
- where the transplant was performed
- the closeness of the donor match
Some people are able to leave the hospital soon after the transplant, while others need to stay for several weeks or months.
The medical team will continue to monitor the person's recovery for up to 1 year. Some people find that effects of the transplant remain for life.
A bone marrow transplant is a major medical procedure. There is a high risk of complications during and after it.
The likelihood of developing complications depends on various factors, including:
- the person's age
- their overall health
- the type of transplant
- the reason for their transplant
Below are some of the more common complications that people who receive bone marrow transplants experience:
- nausea, vomiting, or both
- mucositis, which involves inflammation and soreness in the throat, mouth, and stomach
- graft failure, in which the transplanted cells do not produce new blood cells
- early onset menopause
- organ damage
- graft-versus-host disease, in which the donor cells attack the person's body
- bleeding in the brain, lungs, or other organs
Some people die as a result of complications from bone marrow transplants.
A person who receives a bone marrow transplant may also experience reactions that can follow any medical procedure, including:
The body's response to a bone marrow transplant varies greatly from person to person. Factors such as age, overall health, and the reason for the transplant can all affect a person's long term outlook.
If a person receives a bone marrow transplant to treat cancer, their outlook depends, in part, on how far the cancer has spread. Cancer that has spread far from its origin, for example, responds less well to treatment.
According to the National Marrow Donor Program, the 1-year survival rate among people who have received transplants from unrelated donors increased from 42% to 60% over about the past 5 years.
A bone marrow transplant is a major medical procedure that requires preparation. This involves determining the best type of transplant, finding a donor, if necessary, and preparing for a lengthy hospital stay.
The time that it takes for the body to recover from a transplant varies, depending on factors such as a person's age and overall health and the reason for the transplant.