What are donor stem cell (allogeneic) transplants?

A donor stem cell transplant is a treatment for cancers and conditions that affect the blood cells. This treatment replaces bone marrow that is no longer working properly with healthy stem cells from another person (your donor).

The donor stem cells make new red blood cells, white blood cells and platelets. This gives you a new, healthy bone marrow. The transplant also gives you your donor’s immune system, or white blood cells. This helps your body to get rid of any remaining cancer or leukaemia.

Your donor may be a family member or an unrelated donor. Some people may be given stem cells from an umbilical cord (called a cord blood donation).

Donor stem cell transplants are only done in specialised transplant units by staff with specialist experience. Some people may need to travel quite far to their nearest unit. You will usually need to stay in hospital for several weeks.

Reasons for having a donor stem cell transplant

A donor stem cell transplant can sometimes be used to treat different blood cancers, such as leukaemia, lymphoma and myeloma. It may also be used to treat some other blood conditions.

This treatment may be used when:

  • there is a higher risk of the cancer coming back without it
  • the cancer has come back after other treatment
  • the cancer has not responded completely to treatment.

Deciding to have a donor stem cell transplant

A donor stem cell transplant may increase the chance of being cured, or of getting you into remission more than any other treatment. But it is a very specialised treatment. It can have many side effects and possible complications.

You will need to think about these benefits and risks very carefully before you decide. Your specialist will talk to you about this. Although this can be upsetting, it is important that they tell you about all the possible risks.

We have more information on making treatment decisions that might help. This includes information about getting a second opinion and giving permission (consent) for the hospital staff to give you the treatment. Here are some things you might want to think about:

Risks of a donor stem cell transplant

Your doctor will explain the side effects and possible complications of a transplant before you start treatment. There are likely to be times when you will feel very unwell. It can take many months to fully recover, and some people may not get back to the same level of health they had before their transplant. The main risks include:

  • serious infections and bleeding when your blood cell levels are very low
  • graft-versus-host disease (GVHD) – if the donor’s cells attack some of your body’s tissues and organs
  • the donor stem cells may not produce new blood cells (graft failure).


Unfortunately, most people who have a donor stem cell transplant are no longer able to have children afterwards. This is because of the effects of having high doses of chemotherapy and sometimes radiotherapy. But it will also depend on the intensity of the treatment you have. If you are worried about this, it is important to talk to your specialist before your treatment starts.

We have more information about fertility for men and women.

Research trials

You may be invited to take part in a research trial. Trials and studies are the only reliable way to find out whether a different type of treatment is better than what is already available. We have more information about research trials.

Support from Macmillan

Macmillan is here to support you. If you would like to talk, you can:

Having a donor stem cell transplant

A donor stem cell transplant is a complex treatment, but it can be divided into six stages. We have more information about having a donor stem cell transplant.

Stage 1: Preparing for a donor stem cell transplant

Your specialist will explain the risks and benefits of having a transplant. If you decide to go ahead, your doctors start looking for a suitable donor. You have tests to check your general health, and are given advice on preparing for the treatment. Possible donors are asked to give a blood sample to check that their cells match yours.

We have more information about preparing for treatment.

Stage 2: Having conditioning treatment

Chemotherapy drugs, sometimes with radiotherapy and antibody therapy, are given to destroy your immune system and prepare your body to accept the donor cells.

Stage 3: Collecting your donor’s stem cells

While you are having the conditioning treatment, your donor’s stem cells are collected from their blood or bone marrow.

Stage 4: Having the transplant

After the conditioning treatment, you are given the donor’s stem cells through a drip (infusion).

Stage 5: Waiting for your new blood cells to grow

The donor’s stem cells find their way to your bone marrow and start to grow and make healthy new blood cells. Doctors call this engraftment. You usually need lots of medical and nursing support while the stem cells engraft.

Stage 6: Recovering after your transplant

When your blood cells have recovered and you are well enough, you can go home. Your doctor or nurse will give you advice about the precautions you will need to take to avoid getting an infection. You will have regular appointments at the day unit or outpatient clinic to check your recovery.

Side effects of donor stem cell transplants

After your conditioning treatment your transplant team will monitor you closely for side effects. The side effects you have will depend on the type of conditioning treatment you had.

Most side effects are caused by having low numbers of blood cells. This will gradually improve as you start making new blood cells. While you are in hospital you will have your blood tested every day to check your blood count.

After you go home, you may still have or develop some side effects. Sometimes you may need to go into the hospital for treatment to help manage these. Your transplant team will explain what to expect and when to contact them for advice.

Sometimes side effects may become permanent or only develop years after treatment has finished. Your doctor will explain the possible long term or late effects of your treatment and how you can look after your long term health.

We have more information about the possible effects of stem cell transplants.

After having a donor stem cell transplant

Going home

When your blood counts have reached a safe level, your transplant team will talk to you about going home. Before you go home you will need to:·

  • have recovered enough from all your side effects
  • be eating and drinking well
  • be walking about by yourself
  • be able to take your tablets so you do not need drugs through your line.

You may feel impatient to go home but anxious about leaving the support of the hospital. It can take time to adjust after spending so long in hospital. If you live on your own, you will need to arrange for a relative, friend or partner to stay with you. Or the hospital staff can arrange support from carers when you go home.

Because there are still some things you can’t do, it may seem as though you will never get back to normal life again. As you recover, you will find that things gradually shift away from the treatment and back to day-to-day living.

The first few months out of hospital

After you go home you will still need to go back to the hospital outpatient clinic for regular checks. Even after your bone marrow has recovered and your neutrophils are back to a normal level, your immunity will be low for a few months.

Sometimes you may still need blood transfusions or platelet transfusions. These can usually be given as a day patient. You may have to take regular doses of antibiotics and anti-viral drugs to reduce the risk of infection.

When to contact the hospital

Always carry the 24-hour hospital telephone number you have been given. If you are worried about anything, contact them on that number at any time of day or night.

It is important to take care of your health during this time. Your doctors and nurses will give you advice about what precautions you will need to take once you are home.

Contact your hospital straight away on the number you have been given if:

  • your temperature goes over 37.5°C (99.5°F)
  • you suddenly feel unwell, even with a normal temperature
  • you have any signs of an infection – such as feeling shivery or short of breath, having a sore throat or cough, having diarrhoea or needing to pass urine often
  • you have been in contact with someone who has an infectious disease, for example chickenpox or measles.

If you become unwell, you may need to go back into hospital. It is quite common for this to happen once or twice after high-dose treatment. Although this can be worrying for you, it is not a major setback.

If you feel unwell and are unable to contact the hospital, ask someone to take you to the nearest hospital accident and emergency department immediately.