What is the success rate of bone marrow transplant for aplastic anemia?

Success is judged in several ways: how long people survive, whether the new marrow takes hold, and whether serious complications such as graft versus host disease occur. One headline figure rarely tells the whole story. Results depend on age, the donor type and how well the centre manages conditioning and infection. The registry figures in the section on what the numbers show come from one country and a set period, so ask your team how their own centre's results compare.

How long is recovery after a bone marrow transplant?

Full recovery is usually described as taking up to a year, though the first hospital stay alone often lasts several weeks. Many people find the emotional and practical adjustment takes longer than the medical milestones do. Your team can give a more realistic estimate based on your age, your donor and any complications along the way.

Do siblings always match?

No. Each brother or sister has an independent chance of matching, so one sibling may be a full match while another is not at all. A sibling can also be a half match, sharing only part of the markers. Even a good test result can be overruled by a sibling's own health, age or willingness to donate. A family HLA test is still worth doing early, because it settles the question quickly.

Is a stem cell transplant a cure for aplastic anemia?

For many people, a transplant from a well-matched donor can replace the faulty marrow for the long term, which is why it is described as potentially curative. It is not a guarantee. Infection, graft versus host disease and graft failure can still occur, and some people need monitoring for years for late effects. Ask your team what a cure would realistically mean in your situation.

Stem Cell Transplant for Aplastic Anaemia

A plain-language look at how a donor transplant replaces faulty marrow, how donors are chosen, and what the months afterwards involve.

A transplant that replaces the marrow, not just supports it

For some people with aplastic anaemia, a bone marrow transplant is the one treatment that can replace the faulty marrow altogether. The medical name is allogeneic haematopoietic stem cell transplant. "Allogeneic" means the cells come from a donor rather than from the patient. The procedure is long, demanding and carries real risks, so it is usually discussed only after the team has weighed the other options.

This page covers donors, preparation, complications, recovery and follow-up in general terms. Your transplant team will give you the details that apply to you. In US materials the condition is often spelled aplastic anemia.

Where a transplant fits among the treatments

A transplant is not the only route. The British Society for Haematology guideline for adults lists immunosuppressive therapy as standard first-line treatment for newly diagnosed people with severe or very severe disease, alongside a transplant from a matched sibling donor. The same guideline suggests considering an unrelated donor transplant when immunosuppressive treatment has not worked. In some cases it suggests going straight to transplant for younger adults with severe infections who have a readily available matched unrelated donor. (British Society for Haematology adult aplastic anaemia guideline)

Age, severity, infection history and donor availability all shape that decision. For the non-transplant options, see immunosuppressive therapy and the treatment overview.

Donors and HLA matching in plain words

A transplant works best when the donor's immune markers closely match the patient's. These markers are called human leukocyte antigens, or HLA. Your immune system uses them to recognise which cells belong in your body. Tissue typing is the blood test or cheek swab that reads your HLA markers, and it is usually the first practical step in planning.

When the donor's markers differ too much, the donor's immune cells can attack the patient's body, and the patient's body can reject the new cells. Matching lowers both risks without removing them altogether.

Donors fall into three broad groups. A brother or sister who is a full match is often the first choice. A matched unrelated donor is found through a registry of volunteers. A haploidentical donor shares half of the patient's HLA, usually a parent or child. Because HLA is inherited, relatives and people with a similar ethnic background are the likeliest matches. (NMDP: What is HLA?)

What are the odds that a sibling matches?

Siblings are usually the first place a team looks, so it is worth knowing the odds early. Each brother or sister who shares both parents has a 25% chance of being a full HLA match. For most people who need a transplant, no fully matched donor turns up within the immediate family, which is why registries matter. (NMDP: What is HLA?) A family HLA test is still worth arranging, because it gives the team a clear answer sooner rather than later.

Conditioning before the donor cells arrive

Before the donor cells are given, the body is prepared with conditioning therapy, usually chemotherapy and sometimes radiotherapy. Its job is to clear out the faulty marrow, make space for the new cells and weaken the immune system enough that the donor cells can settle. For aplastic anaemia the conditioning is generally chosen to be less intense than the regimens used for many leukaemias, because the marrow is failing rather than full of cancer cells. The team adjusts the intensity to your age, general health and donor type.

Conditioning lasts a matter of days. Because the immune system is weakened at this point, people are usually nursed in their own room.

The stages, from transplant day to the first year

The table gives a rough timeline. Individual timing varies a great deal, and your team will tell you where you are at each point.

Typical phases of an allogeneic transplant (approximate and varies by person)
Phase	What usually happens
Transplant day	The donor cells are given through a thin tube placed in the chest or upper arm. The process is much like a blood transfusion, is not usually painful and does not need a general anaesthetic.
Engraftment, the early weeks	The new cells begin to settle in the marrow and make blood cells. Counts stay low during this stage, so transfusions and infection precautions continue. Timing varies from person to person.
The first 100 days	This is the period of highest concern for infection and graft versus host disease. Check-ups are usually weekly at first, and preventive medicines are given.
Months after the first 100 days	Strength and blood counts usually improve gradually. Activity increases step by step, and the team reviews the medicines that suppress the immune system.
Up to the first year	Full recovery can take up to a year. Vaccinations are restarted on the team's advice. (NHS: recovering from a transplant)
Long term	Follow-up continues for late effects, including effects on fertility and any problems that appear later.

Graft versus host disease, graft failure and infection

Donor cells can react against the recipient's body. This is graft versus host disease. It can start soon after the transplant or later on, and it can affect the skin, gut, liver, mouth, eyes, lungs and joints. Early treatment eases symptoms, and the team tailors preventive treatment to the donor type and to the patient's risk. (NHS: complications of a transplant)

Graft failure is less common. It happens when the donor cells do not establish themselves or stop working. Teams watch blood counts closely for it and have options if it occurs, including further treatment and, in some cases, another transplant.

Infection is the other major early risk. Contact your care team straight away if you have:

a high temperature, or feel hot, cold, sweaty or shivery
signs of infection such as a sore throat, cough, diarrhoea or pain when passing urine
throbbing pain, swelling and warmth in a leg or arm
sudden breathlessness or sharp chest pain

What the numbers show

Outcome figures depend heavily on the study behind them. A national registry study from China followed 342 people with severe aplastic anaemia who had a transplant from either a haploidentical donor or an identical sibling donor between 2012 and 2018. The estimated 9-year overall survival was 87.1% with a haploidentical donor and 89.3% with an identical sibling donor, a difference that was not statistically significant. Chronic graft versus host disease at 5 years was more common after haploidentical transplants, at 29.3% against 10.4%. (Haematologica registry study, 2022)

That is one study from one country, so treat it as an example rather than a prediction for you.

Long-term follow-up and the meaning of a cure

Recovery is usually followed by regular check-ups for years, to watch blood counts, chronic graft versus host disease and other late effects. Radiotherapy and some chemotherapy can affect fertility, so people often ask about options before treatment starts.

Many people find the physical and emotional side of recovery settles more slowly than the blood counts. The page on living with bone marrow failure covers the everyday steps.

Where aplastic anaemia is inherited, as in Fanconi anaemia, the transplant decisions are different. Without a family match, an unrelated donor can only be found if enough people have joined registries; see becoming a stem cell donor.

Some people also benefit from physiotherapy or help with the strain of a long illness, and your team can point you towards those services.

A transplant can offer a lasting replacement, but it is a decision to weigh with your team

The transplant is the one approach that replaces the marrow itself. Ask your haematology team to explain the odds in terms of your own age, health and available donors.

This page explains a medical topic in general terms. It can't account for your own results or history, so please talk anything through with your haematology team before acting on it.

Bone marrow transplant for aplastic anaemia: what to expect