Haemopoietic stem cell transplants (HSCT) can be called different things depending on where the stem cells are collected from. Bone marrow transplants (BMT) refers to the cells being collected from the bone marrow, peripheral blood stem cell transplants (PBSCT) also known as stem cell transplant refers to them being from the bloodstream, and umbilical cord blood (UCB) transplant refers to the cells being collected from the umbilical cord of a newborn baby.
Bone marrow transplants (BMT) have successfully been used for many years to treat individuals with leukodystrophy.
There are three types of transplant:
A haemopoietic stem cell or bone marrow transplant is a long and complicated process that involves 5 main stages.
These stages are described in more detail below.
Before a stem cell transplant can be carried out, you’ll need a series of tests and examinations to ensure you’re healthy enough for the procedure to be carried out.
Transplants tend to be more successful in people who are in good general health, despite their underlying condition.
The tests you might have include:
There are 3 main ways stem cells can be harvested, these are:
The most common way to harvest stem cells involves temporarily removing blood from the body, separating out the stem cells, and then returning the blood to the body.
To boost the number of stem cells in the blood, medication that stimulates their production will be given for about 4 days beforehand. On the fifth day, a blood test will be carried out to check there are enough circulating stem cells.
If there are enough cells, veins in each arm will be connected by tubes to a cell-separator machine. Blood is removed from one arm and passed through a filter, before being returned to the body through the other arm.
This procedure isn’t painful and is done while the donor is awake. It takes around 3 hours and may need to be repeated the next day if not enough cells are removed the first time.
An alternative method of collecting stem cells is to remove around a litre of bone marrow from the donors’ hip bone using a needle and syringe.
The needle may need to be inserted into several parts of your hip to ensure enough bone marrow is obtained. This is done under a general anaesthetic, so you’ll be asleep and won’t feel any pain while it’s carried out.
However, the area where the needle is inserted may be painful afterwards and you’ll have marks on your skin where the needles were inserted (usually one on each side).
reatment with high doses of chemotherapy and sometimes radiotherapy will be needed before the stem cells can be transplanted to:
As part of the conditioning treatment, you’ll be given a range of medicines, so a tube called a central line will usually be inserted into a large vein near your heart. This means medication can be passed into your body without the need for lots of injections.
The conditioning process usually lasts up to 10 days. You’ll probably need to stay in hospital throughout the treatment.
Conditioning can cause a number of unpleasant side effects, such as sickness, hair loss and tiredness. These are usually temporary. Your treatment team will discuss the risks of treatment with you beforehand.
The transplant will usually be carried out a day or 2 after conditioning has finished.
The stem cells will be passed slowly into your body through the central line. This process often takes a couple of hours.
The transplant won’t be painful, and you’ll be awake throughout.
Once the transplant is finished, you’ll need to stay in hospital for a few weeks while you wait for the stem cells to settle in your bone marrow and start producing new blood cells.
During this period you may:
Many people are well enough to leave hospital between 1 and 3 months after the transplant. However, if you develop complications such as an infection, you may not be able to leave hospital for longer.
Even after going home, you’ll still be at risk of infections for potentially a year or 2 because it can take a while for your immune system to return to full strength.
If donated stem cells were transplanted, you’ll also usually need to take medicines that stop your immune system from working so strongly, to reduce the risk of your body attacking the transplanted cells (immunosuppressants), or to reduce the risk of the transplanted cells attacking other cells in your body.
Patients will be followed regularly after BMT to ensure that they remain healthy and to carry out routine checks. They will be followed for a number of years post-transplant.
To find out more about the long-term effects of a stem cell transplant, Anthony Nolan Trust has information here.