Stem cell or bone marrow transplants can be life-saving for people living with certain cancers and blood disorders. However, finding a suitable donor is often complicated and time-consuming. Patients generally struggle to find a match within their family, so their doctors may turn to stem cell registers – where extraordinary people offer their own cells to strangers – to search for a potential donor.

Earlier this month, we visited the charity Anthony Nolan – the world’s first stem cell register – to learn more about how matches are (hopefully) made and why it’s vital that they are.

What is a stem cell transplant?

Stem cells are unique cells that can self-renew and develop into many different cell types in the body. Depending on where they are found, stem cells can develop into different tissues. For example, hematopoietic stem cells – found in the blood, bone marrow, and umbilical cord – can develop into all blood cell types, including red blood cells, white blood cells, and platelets.

Usually, the stem cells found in the bone marrow produce the right amount of each type of blood cell to keep us healthy – but when things go wrong, and the body produces too many blood cells that are not fully developed, blood cancers or blood disorders can arise.

For patients with these conditions, a stem cell transplant may be their best chance of survival. 

Before a transplant can take place, patients undergo chemotherapy and/or radiotherapy to remove their faulty stem cells. Then, doctors will give healthy, donor stem cells to the patient via their bloodstream – the transplant is very similar to a blood transfusion but takes a little longer. The transplanted stem cells travel to the patient’s bone marrow where they attach and grow, before making new blood cells.

The world’s first stem cell register

Anthony Nolan is a UK-based stem cell transplant charity that matches people in need of transplants to potential donors. In doing so, they give blood cancer and blood disorder patients a second chance at life.

“We were set up in 1974 by an amazing woman called Shirley Nolan,” Rowena Bentley, Head of Programme and Community Recruitment at Anthony Nolan, told IFLScience. “She was searching for a matching donor for her son Anthony who was diagnosed with a rare blood disorder. At the time, there was no stem cell register, there was no way of finding a potential match for her son, and so she decided that she would do something incredible and try and set up the world’s first stem cell register.”

Often, those people won’t find a match in their family, which is why they turn to us at Anthony Nolan and they turn to a stranger to donate their stem cells.

Rowena Bentley

Since its inception, the charity has facilitated over 26,500 transplants for people around the world and has provided dedicated patient support and specialist nurses, alongside conducting pioneering research to increase transplant success. 

The cause is as relevant now as it was 50 years ago, and so Anthony Nolan continues to unite people and science to unlock cures, treatments, and transplants to give patients the best chance – and quality – of life. Their ability to do so is tied to the register: “Often, those people won’t find a match in their family, which is why they turn to us at Anthony Nolan and they turn to a stranger to donate their stem cells,” Bentley added.

There are currently over 900,000 people signed up to the Anthony Nolan register – but even with these numbers, finding a viable match is not easy.

It starts with a swab

We paid a visit to the Anthony Nolan sample processing labs to find out how potential donors’ samples are processed in the hope of matching them to a patient and to learn more about the life-saving work that the charity does.

Joining the register is quick, free, and easy: you can sign up online and, if eligible, will be sent a swab to rub around the inside of your cheek and post back to the lab.

Then, the laboratory scientists get to work, using these samples to search for a donor whose tissue type closely matches the patient’s. 

First-time sign-ups to the register have the DNA on their cheek swabs processed so they can be potentially matched to a patient. Donors and patients who are a possible match then send in blood samples to have their DNA double-checked and their blood tested for viruses and blood type.

The first stage of this process is to extract DNA from the donor and patient samples, which are quantified, normalized to be the same concentration, and sent on to be sequenced. Blood samples are separately tested for viruses. For donor samples, four viruses are screened for – Hepatitis B, Hepatitis C, HIV, and cytomegalovirus (CMV) – while patient samples are just tested for CMV. Their blood group is also checked.

For the sequencing, DNA must first be amplified so it can be measured by the sequencing machine. This occurs in a reaction known as Polymerase Chain Reaction (PCR), which creates millions to billions of copies of DNA. The focus is specifically on the HLA genes – these important genes encode proteins that allow the immune system to identify which cells belong in your body and which don’t. As such, matching HLA genes between patient and donor is crucial to increase the chances of a successful stem cell transplant.

After amplification and an additional quality check, called gel electrophoresis, the DNA is chopped up into small pieces and sticky ends are attached to the edges of these fragments, before the samples are cleaned to remove any contaminants. Then, barcodes are added to the DNA fragments to identify which DNA belongs to which sample, and they are all loaded onto a next generation sequencer to finally discover the HLA genes unique to each person – this is what will reveal a potential match to a patient.

Sequencing data is then analyzed, and the results are sent to transplant centers to help them choose the most appropriate donors for their patients. 

Saving lives through stem cells

Around 250,000 people in the UK are living with blood cancer, making it the fifth most common type of cancer and the third biggest cancer killer. It’s a similarly bleak outlook across the pond too. 

Transplants, therefore, offer a much-needed beacon of hope, as do stem cell registers like Anthony Nolan’s.

Pretty certain to say my quality of life would not be like this without the transplant.

Raj Parmar

“If we didn’t have the stem cell register then people would only be able to have a transplant if they had a match in their family, and we know that for most people there isn’t a match in their family,” Bentley explained. “So through the stem cell register, we are providing an opportunity for thousands of people to survive.”

One such person is Raj Parmar, who was diagnosed with a type of blood cancer called myelofibrosis in 2015.

“I knew from the outset that [a stem cell transplant] was the only curative treatment,” he told IFLScience.

“I have one sibling – they tested my brother, he wasn’t a match,” but through the Anthony Nolan stem cell register, Parmar was able to find a donor and underwent a stem cell transplant in 2020. Now four years post-op, Parmar’s life has changed for the better:

“In those last four years, I’ve done so many amazing things: I’ve worked in New Zealand, I’ve been traveling, I’ve just been able to do so much more. I’ve been active again, I’m probably the fittest I’ve ever been.”

“Pretty certain to say my quality of life would not be like this without the transplant,” Parmar added.

Joining the register

Signing up to a stem cell register could help save a life. To be eligible for Anthony Nolan’s you must be aged 16-30 and healthy.

“We particularly need young men to join the register,” Bentley explained. There is also a pressing need to recruit more people from diverse backgrounds to the register, to help more patients from minority ethnic backgrounds find the matches they need.

“The more people on the register, the better chance that we have of finding everybody who needs a match their best possible match.”

More information about joining the register can be found on the Anthony Nolan website.