How to join the stem cell register and what donation involves

Why a stranger's swab can matter so much

For some people with aplastic anaemia (aplastic anemia in US usage), a stem cell transplant from a donor is part of the treatment discussion. Our overview of aplastic anaemia treatment explains where transplant fits alongside other options. This page is for anyone who has wondered whether they could help, whether as a relative, a friend or someone who has simply read about the need.

Donors are often strangers. Anthony Nolan puts it simply: a stem cell transplant from a stranger can be someone's only hope. Registers exist so that a suitable match can be found when nobody in the family is one.

Why unrelated donors matter in marrow failure

In marrow failure, the bone marrow does not make enough healthy blood cells. A transplant replaces the faulty marrow with stem cells from a donor, and NMDP explains that these cells help rebuild the patient's entire blood and immune system. When a brother or sister is not a suitable match, transplant teams search registers for an unrelated donor instead. See also stem cell transplant for aplastic anaemia for how the transplant itself is planned.

Matching depends on human leukocyte antigen (HLA) genes, which act as markers on most cells in the body. The closer the match between patient and donor, the better for the patient. As populations become more diverse, full matches are harder to find, which is why the size and variety of a register matter so much.

Why patients from minority ethnic backgrounds can find matches harder

Anthony Nolan explains that people from minority ethnic backgrounds are more likely to have unique tissue types, so fully matched unrelated donors can be harder to find for them. The remedy is partly a matter of numbers. The more potential donors from those backgrounds join a register, the better the odds for patients who need one.

Anyone who meets the eligibility rules can join, whatever their background. Each new donor adds to the pool for the next patient who needs one.

Who can join, and the age limits

Joining is open to people who are generally fit and healthy, but the age limits differ between registers. The table sets out the published limits for three registers, two in the UK and one in the US.

DKMS UK says that if you are aged 16 to 55 and in general good health, you may be able to register. Anthony Nolan's upper limit is 30, so anyone older should check the other registers before deciding. Anthony Nolan and NMDP both say donors can be asked to give until they turn 61.

Some conditions and medicines can rule people out. Anthony Nolan notes that PrEP can stop someone from donating for a period, so anyone taking it should check with the register before applying.

How the swab kit works

Signing up usually begins with an online form. It asks for basic details such as your age and weight, plus questions about your medical history, which the register uses to check eligibility and general health. Anthony Nolan says it will not add anyone whose donation it is concerned could be too much for them.

Once approved, a swab pack arrives by post. Swabs do not hurt, and the instructions simply ask you to move the swab around the inside of your mouth before posting it back. NMDP describes a similar at-home kit that collects cheek cells, usually delivered within three to seven business days of signing up.

Joining does not mean you will be asked to donate, and most people on a register never are. A match needs a close tissue type fit, so it may be months, years or never before a call comes. Keeping your contact details up to date is what keeps you reachable when it does.

What donating involves

Donors give through one of two procedures, and the patient's doctors choose which one suits the patient. Anthony Nolan says about 90% of donations are peripheral blood stem cell collections, with the remaining 10% taken from bone marrow.

• Peripheral blood stem cell collection: a course of injections over a few days, then a procedure of around four to five hours. Blood is drawn from one arm, passed through a machine that separates out the stem cells, and returned through the other arm.
• Bone marrow donation: cells are collected from the hip bone under general anaesthetic, and Anthony Nolan describes a hospital stay of about two nights.

Does it hurt? Peripheral collection is closer to giving blood than to surgery, though NMDP lists tingling around the mouth and fingers and mild muscle cramps among the possible side effects. Anthony Nolan notes that bone pain from the injections is common, and marrow donors may feel achy and bruised around the hip for a while afterwards. Recovery differs from person to person, so it helps to talk through what to expect with the donation team beforehand.

Giving blood and platelets as another way to help

Not everyone can join a stem cell register, and blood donation is another route. In the UK, NHS Blood and Transplant says you should be generally fit and well, aged 17 to 65 for a first donation or up to 72 if you have given before. Men can give every 12 weeks and women every 16 weeks.

One rule matters for people with aplastic anaemia. NHS Blood and Transplant lists having received blood, platelets or plasma after 1 January 1980 as a reason someone cannot donate blood, so anyone who has had transfusions should check before booking. Our page on blood and platelet transfusions covers that side of care, and your haematology team can confirm how the rule applies to you.

In the US, the American Red Cross says platelet donors help cancer patients and others who depend on them. Platelet donation is a separate process from stem cell donation, and the Red Cross describes how it works on its own pages. Rules differ between countries, so check with your local service before you book.

Joining is quick and free, and it keeps the register ready for the next patient

Anthony Nolan describes joining as easy and free, and most people who sign up will never be called. That is no reason to hold back. A register only works when enough people are on it, and a single match can change the outlook for someone who has been waiting.