Beta thalassemia is a genetic blood disorder that’s inherited from biological parents and is characterized by low levels of hemoglobin. Hemoglobin is the iron-containing part of your red blood cells that allows them to carry oxygen around your body.
Thalassemia is classified as minor, intermedia, or major depending on how severe symptoms are. It’s caused by a mutation in the HBB gene. People with thalassemia minor receive an abnormal HBB gene from one biological parent while people with intermedia or major receive genes from both parents.
Until recent years, most people with thalassemia major died soon after birth. Now people with this condition can lead long lives with proper treatment.
Two treatments are used to increase the quality of life in people with thalassemia major:
- chronic blood transfusions with chelation and removal of excess iron from blood
- bone marrow transplant
A bone marrow transplant is the only potential cure.
Read on to learn more about how bone marrow transplants are used to treat beta thalassemia major.
Your blood cells are made from stem cells inside your bone marrow. People with beta thalassemia major produce blood cells with low levels of functional hemoglobin and have an impaired ability to carry oxygen throughout their body.
A bone marrow transplant is a potential cure for beta thalassemia major, but it’s usually reserved for people with serious disease since it has the potential for life threatening complications.
The procedure starts by receiving high amounts of chemotherapy or radiation therapy to destroy the cells in your bone marrow that produce abnormal blood cells. Once these cells are killed, you receive an allogeneic stem cell transplant.
An allogeneic transplant involves replacing your own bone marrow stem cells with stem cells from a donor. A donor is usually a person who is a close genetic match, such as a sibling or parent, but it can also be someone you don’t know.
A donor needs to have a compatible human leukocyte antigen (HLA) type. HLA are proteins on your cells that your immune system uses to determine whether the cells are foreign.
Only about 1 in 5 people have a family member who’s an acceptable HLA match.
Thalassemia major used to have a very poor outlook. In the 1920s, essentially all people with thalassemia major died within 6 months due to complications, such as:
- heart failure
- liver failure
- gonadal failure (failure to produce sex hormones)
- endocrine failure (failure to produce other hormones)
Outcomes are much better today due to improved treatment. As of now, an allogeneic bone marrow transplant is the
In a 2016
- 88% of people survived for at least 2 years and at least 81% had no signs of thalassemia for 2 years
- 91% of people who received a transplant from a sibling survived at least 2 years and 83% had no signs of thalassemia for at least 2 years
- 90% to 96% of people under the age of 14 survived at least 2 years and 83% to 93% had no signs of thalassemia for at least 2 years
In a 2017 review of studies, researchers reported survival rates in the studies they reviewed ranging from 66% to 99% when the donor was a sibling. The largest study they reviewed, with 222 children, reported a survival rate of 82%.
When the donor wasn’t related to the person with thalassemia, the survival rates ranged from 62% to 100%. In the largest study, with 122 people, the survival rate was 84%.
High doses of chemotherapy can damage healthy cells in your body and cause many side effects. In high-risk people, the mortality rate is as high as
Complications can include:
- thyroid dysfunction
- heart failure
- delayed puberty
- decreased growth height
Graft versus host disease is a potentially serious complication where your immune system attacks the new cells. It can occur within a few months or sometimes 1 to 2 years later. Symptoms can range from mild to life threatening. They include:
In a 2022
You’ll be admitted to the hospital or transplant center on the day treatment starts. You’ll first receive high amounts of chemotherapy or radiation therapy to destroy the cells producing abnormal blood cells. You’ll likely receive chemotherapy through a central line inserted into a large vein near your heart.
You’ll likely need to stay in the hospital or treatment center while receiving chemotherapy or radiation therapy. This phase usually lasts about 1 to 2 weeks. You may develop side effects like nausea and hair loss.
The stem cell transplant is usually started 1 or 2 days after the chemotherapy or radiation. The stem cells will be painlessly infused through the central line into your bloodstream. You may need to stay at the treatment center for several weeks while you wait for the stem cells to produce new blood cells.
Most people can leave the treatment center 1 to 3 months after a transplant, but you may have to wait longer if you develop an infection or other complications.
A stem cell transplant is usually reserved for people with severe thalassemia who don’t respond well to other treatments. Eligibility is determined on a case-by-case basis.
Ideally, the transplant should be performed before the development of:
An allogeneic bone marrow transplant is the only potential cure for beta thalassemia major. It involves receiving high amounts of chemotherapy or radiation to destroy cells producing abnormal blood cells. Bone marrow cells are then infused into your blood from a donor to replace your abnormal cells.
Allogeneic bone marrow transplants can be highly effective for treating thalassemia, but they come with risks of severe complications. Outcomes are generally best when they’re performed early in life.