Neoplastic blood diseases (blood cancers) often require chemotherapy, with or without radiotherapy. In some patients, chemotherapy will be sufficient to control the disease. In other cases, chemotherapy is not enough; and a stem cell transplant (autologous or allogeneic) is required.
Autologous haematopoietic stem cell transplants (HSCT) is where a patient’s own blood-forming cells are collected and returned to the patient following high dose chemotherapy.
Allogeneic stem cell transplant is where stem cells are collected from a matching donor and transplanted into the patient to suppress the disease and restore the patient’s immune system.
The possibility of having a stem cell transplant to treat your disease relies on the availability of a suitable stem cell donor. The greater the immunological compatibility (HLA identity) between you and the donor, the lower the risk of experiencing complications after the transplant.
Human Leukocyte Antigen (HLA) proteins are located on the surface of most cells in your body. HLA proteins are the main way the immune system tells the difference between your own and foreign cells, and the degree of HLA matching between you and your donor is the single most significant factor contributing to a successful transplant.
Therefore, in theory, your ideal donor would be an identical twin (syngeneic transplant). In this case, there would be no risk of your body rejecting the graft or experiencing GVHD; however, you would not benefit from the antileukaemic effect of the graft either, thus increasing the risk of relapse after the transplant.
In neoplastic diseases, a matched sibling will be preferred as your donor, however, only about 30% of patients who require an allogeneic transplant have a matched sibling donor. For the remaining patients, a matched-unrelated donor, a haploidentical related donor or a cord blood unit must be found.
If you require a donor urgently, haploidentical and cord blood transplantation are preferred. Cord blood can be obtained promptly because they are cryopreserved and in inventory in cord blood banks, whereas haploidentical family members are usually willing to donate and can be scheduled for stem cell collection more promptly than unrelated donors.
How to prepare for a stem cell transplant
Haematopoietic stem cell transplant is a complex and long procedure involving different phases, before and after the transplant. Generally speaking, there are five stages:
Stage 1: Tests and examinations
Stage 2: Harvesting
Stage 3: Conditioning
Stage 4: Transplanting the stem cells
Stage 5: Recovery
Tests and examinations
Before you have a stem cell transplant, your medical team needs to perform some tests to ensure you are fit enough to undergo the process. This usually takes a couple of days, and the tests might include:
- X-ray and/or computerised tomography (CT) scan
- Blood tests
- Electrocardiogram (and, occasionally, echocardiogram)
- Dental check-up
- Respiratory, and gynaecologic and other tests.
Harvesting stem cells
If you are having an autologous haematopoietic stem cell transplant, your own stem cells will be collected and stored frozen before you receive your high-dose chemotherapy (conditioning treatment). These cells are transplanted back in to your body after killing the cancerous cells.
If you are having allogeneic transplantation, the stem cells are harvested from the donor and given directly to you without needing to store them.
Stem cells can be harvested from peripheral blood or from the bone marrow.
Your conditioning treatment consists of chemotherapy, with or without radiotherapy, given to eliminate as much diseased cells as possible and to prepare your body for receiving the stem cells that will be transplanted soon after.
Conditioning treatment is typically given during the week before your transplant and is given both in autologous and allogeneic transplantation.
Depending on their intensity, conditioning regimens are classified, from more to less intense, as high-dose (myeloablative), reduced-intensity, and non-myeloablative. Your doctor will discuss with you the best option for your particular case.
The stem cells are infused slowly into your body through the same central line used for giving you drugs, and the process usually takes between 30 minutes and an hour. The transplant is not painful and you will be awake throughout.
After the transplant, you need to stay in hospital for at least a few weeks, until the infused stem cells settle in your bone marrow and start producing new blood cells.
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In 2018, Sophie’s brother was diagnosed with leukaemia.
Here, she talks about what it was like to be his stem cell donor.
In April, my family had the heart-breaking news that my brother Myles, who is serving the British Army and based in Germany, was diagnosed with acute lymphoblastic leukaemia (ALL).
I contacted Leukaemia Care, who sent out various magazines to read through, and I sent these to Myles so he could get his head round the diagnosis and the treatment he would receive.
After a series of chemotherapy, we were told that Myles needed a stem cell transplant to have a chance to recover from his illness. Whilst I was visiting him in Germany, I had a blood test taken to see if I was a possible donor. When I received the phone call to say I was a match, I was very emotional; I couldn’t quite believe it.
I underwent several tests and examinations to check I was fit enough and then flew home with my injections ready to start on the 19th August. I was feeling nervous about the injections, but it was nowhere near as bad as I thought. I had to do this procedure twice a day with the last injection being the morning of the stem cell collection. Within a couple of days, I was getting some pain in my lower back and rib cage. It was bearable, but all I could think was it must be working and it was nothing like what my brother was going through.
The doctors and nurses were fantastic. They put me at ease immediately and before I knew it I was connected to the machine. It was fascinating to see my blood spinning and my cells being collected. They talked me through the process and I didn’t feel anything as the blood was coming back into me at the same time it was going.
It took four hours for them to collect enough stem cells and, as it was coming towards the end, I could feel myself getting more emotional. Finally, when the machine turned off and they said my cells were off to be analysed, I cried. I was excited but apprehensive for Myles. There are only 11 months and two weeks difference between us, so we have always been close, and to be the one who could potentially save his life was the best feeling in the world. Time will tell how this will work out but they seem very positive, especially with me being a 100% match.
If you get the opportunity to be a stem cell donor for either a relative or for someone unknown, please jump at the opportunity. The feeling you get yourself is amazing and the patient will get a second chance. That’s down to you.