Haploidentical Stem Cell Transplant
May 6, 2024
This page was reviewed under our medical and editorial policy by Leslie Popplewell, M.D., Hematologist and Medical Director of Hematology and Blood and Bone Marrow Transplant, City of Hope Atlanta
A haploidentical transplant is one type of stem cell transplant used to treat certain blood cancers, also called hematologic malignancies. In all, 1,444 haploidentical transplants were performed in 2018, according to the Center for International Blood and Marrow Transplant Research, with numbers increasing over time.
This guide to the haploidentical stem cell transplant process is designed to help patients and their families learn more about what to expect.
What Is a Haploidentical Transplant?
A haploidentical transplant is a type of allogeneic stem cell transplant. Instead of using a donor with a full genetic match to the patient, a haploidentical transplant uses a donor who is a partial genetic match. The donor in this procedure — also called a haplo or half-match transplant — is usually a family member.
The donor will be a partial match to the patient’s human leukocyte antigen (HLA), a type of protein found in the body’s cells.
During a haploidentical transplant, stem cells are collected from the donor and then infused into the patient.
This treatment is used to treat certain types of blood cancer, including:
Benefits of Using a Haploidentical Donor
There are benefits to using a haploidentical donor in this type of bone marrow transplant. Because the bone marrow transplant donor is a partial match to the patient, it’s easier to find someone. With more potential donors, a transplant may be performed sooner as well.
Certain ethnic groups, patients with few living family members, patients who are adopted and have no children, or those who are estranged from their family may find it easier and faster to find a donor when an exact genetic match isn’t required.
What’s the Success Rate of Haploidentical Transplant?
Haploidentical bone marrow transplant success rates are constantly improving, thanks to medical advances. One research study published in Transplantation and Cellular Therapy found a 79.4% survival rate one year after transplant, demonstrating similar outcomes to those who had an allogeneic transplant that was a full match.
However, each patient’s medical situation is unique, and the care team will be able to answer specific questions about health outcomes.
Haploidentical Bone Marrow Transplant Process
The first step of the haploidentical stem cell transplant process is conditioning, when high-dose chemotherapy, and possibly radiation therapy, is given to destroy cancer cells and prepare the patient for the transplant. Conditioning may cause side effects, but the care team will let a patient know what to expect.
Next, the infusion will occur after the patient has had time to recover from conditioning. During the infusion, the stem cells are first harvested from the donor, then processed and given to the patient without delay. The infusion is delivered via a catheter, similar to a blood transfusion. How much time it takes depends on how much fluid surrounds the stem cells. During the infusion, the patient is awake and typically feels no discomfort.
Patients are closely monitored and tested after the infusion, but the care team will let them know what to expect throughout the process.
Recovery From Haploidentical Stem Cell Transplantation
Recovery after a haploidentical stem cell transplant is a lengthy process, requiring both time in the hospital and recuperation at home. After an allogeneic transplant, the patient may spend about 40 days in the hospital or transplant center under close medical supervision.
It takes about two to six weeks following the infusion for the new cells to engraft, meaning they begin to reproduce in the body and create new, healthy cells. Antibiotics are often given during this time to reduce the risk of infection.
After the patient returns home from the hospital, it may take at least six months or more to regain normal immune system functions and blood count levels, so the recovery process may be long. This may be challenging, both mentally and physically, so it’s important for patients to have a support system in place. The patient’s care team will also provide helpful resources and support during the recovery process.
Learn more about stem cell and bone marrow transplant recovery
Side Effects of Haploidentical Transplant
Side effects may follow a haploidentical transplant, both immediately after the procedure and also later on. If patients notice any unexpected changes to their body, they should contact their care team for advice.
Since haploidentical transplants use cells from a donor, the patient is at risk of developing graft-versus-host disease (GVHD), which occurs when the donor cells attack the body and cause inflammation. It may be acute or chronic, but patients will be given medication to help prevent the condition from developing.
Patients also are at a higher risk of infection after a haploidentical transplant, as chemotherapy or radiation therapy may weaken the immune system. The risk is highest in the first few weeks after the transplant, so care should be taken to reduce the risk.
After a haploidentical transplant, a patient may experience immediate side effects that include:
- Fatigue
- Hair loss
- Low levels of red blood cells (anemia) and platelets
- Mouth sores
- Weight loss
- Nausea and vomiting
- Changes in taste
- Loss of appetite
Some side effects may not develop until several months or years after the transplant. These may include:
- Thyroid problems
- Bone and lung damage
- Early menopause
- Infertility
- Cataracts
Patients may also go on to develop another type of cancer.
Not all patients experience all side effects, as each person’s medical situation is unique. The patient’s care team will advise on what to look out for and how to manage any side effects that may develop.
D’Souza A, Fretham C, Lee SJ, et al. (2020). Current Use and Trends in Hematopoietic Cell Transplantation in the United States. Transplantation and Cellular Therapy, 26(8), e177-e182.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7404814/American Cancer Society (2023, May 4). Types of Stem Cell and Bone Marrow Transplants.
https://www.cancer.org/cancer/managing-cancer/treatment-types/stem-cell-transplant/types-of-transplants.htmlMcCurdy S, Luznik L (2019). How we perform haploidentical stem cell transplantation with posttransplant cyclophosphamide. Blood, 134(21), 1802–1810.
https://ashpublications.org/blood/article/134/21/1802/428775/How-we-perform-haploidentical-stem-cellChang J, Akhtari M (2018). Haploidentical Stem Cell Transplantation Leads to Similar 100 Day and 1 Year Overall Survival Rates Compared to Matched Related Donor and Matched Unrelated Donor Transplants. Transplantation and Cellular Therapy, 24(3), S336-S337.
https://www.astctjournal.org/article/S1083-8791(17)31295-8/fulltextBertz, H (2021). Rehabilitation after Allogeneic Haematopoietic Stem Cell Transplantation: A Special Challenge. Cancers (Basel), 13(24), 6187.
https://www.mdpi.com/1395476American Society of Clinical Oncology (2022, August). Side Effects of a Bone Marrow Transplant (Stem Cell Transplant).
https://www.cancer.net/navigating-cancer-care/how-cancer-treated/bone-marrowstem-cell-transplantation/side-effects-bone-marrow-transplant-stem-cell-transplant