Patients and families taking part in family camp activities

Sibling stem cell transplants

If you’ve found out that you need a stem cell transplant, sometimes your biological sibling can be your stem cell donor. On this page we’ll explain what sibling transplants mean, how they work and why you might need one.

What’s on this page?

What is a sibling stem cell transplant?

If you're receiving stem cells donated from someone else, doctors need to find a donor whose tissue type matches yours. A sibling transplant means that you will have a transplant using stem cells donated from your biological sibling.

As your siblings have a 25% chance of having the same tissue type as you, your transplant team will normally ask if they would like to be tested first.

What is a stem cell transplant?

If you haven’t yet read our page on understanding stem cell transplants, we recommend taking a look at the information to help you learn what it involves.

Who can have a sibling transplant?

If doctors confirm that your sibling’s tissue type matches yours, a sibling stem cell transplant could be a treatment option if you have:

  • A blood condition that means that you can’t make your own healthy blood cells, for example aplastic anaemia.
  • A genetic condition affecting your blood, bone marrow or immune system.
  • A type of blood cancer that chemotherapy is unlikely to cure.
Will and George

Speaking to other people, I recognise how lucky I am to have had one donor and for it to be a 10/10 match. If it wasn't for George, I would have desperately needed a stranger's help. It could have been a completely different story – I was just lucky.

Will received stem cells from his brother George to treat acute lymphoblastic leukaemia (ALL). You can read their story on our blog.

How does your sibling donate their stem cells?

If your sibling is a match and they want to donate, your transplant centre will arrange a ‘donor assessment’. This also involves a medical screening to make sure they are fit and healthy enough to donate.

Unfortunately, if your sibling has certain medical conditions, they won’t be able to donate to you. If this happens, there are other options for finding you a donor.

If your sibling is a match and can donate, the next steps are as follows:

  1. Book a date for their stem cell donation.
  2. Decide on the best way to donate:
  3. Donate their stem cells in the way they have chosen.
  4. Book a date for your transplant using their collected stem cells.

The entire decision is voluntary – it’s up to them if they want to donate. For more information, see our page on donating your stem cells to a relative.

What will happen before the transplant?

For a sibling stem cell transplant, you will have conditioning therapy to prepare your bone marrow and immune system for the new stem cells. You will probably have chemotherapy, sometimes in combination with a type of radiotherapy called total body irradiation (TBI). This also helps to get rid of any damaged cells if you have any left.

What will happen during the transplant?

Your sibling stem cell transplant normally takes place the day after the conditioning therapy has finished. The transplant itself involves having your sibling’s stem cells passed through liquid in a thin tube into your bloodstream, a bit like having a blood transfusion.

You shouldn’t experience any pain – a transplant is not an operation and you’ll be awake the whole time.

Recovering from a sibling stem cell transplant

After your transplant, your sibling’s stem cells make their way to your bone marrow. Once there, they start to grow into normal blood cells – this is called engraftment. The length of time spent in recovery is different for everyone.

You’ll probably stay in hospital for about three to four weeks in protective isolation. You’ll stay in your own hospital room with safety measures taken to protect you from infection. For more information, see our page on your stay in protective isolation.

After you go home, it usually takes at least six months before your level of activity starts to get back to how it was before.

Will I get side effects after a sibling stem cell transplant?

After any type of transplant, many people experience a range of side effects, both short and long term. Most side effects apply to all types of transplants, while others are more specific to certain types.

Information updated: 24/05/2024

Next review due: 24/05/2027