Stem Cell Transplantation
Transplantation Laboratory – Manchester Royal Infirmary
Stem Cell Transplantation
In a recent newsletter article I described the work the team do at the laboratory to support solid organ transplantation. In this article I cover the work they do in relation to Hematopoietic Stem Cell Transplantation.
I met with Natalia Diaz-Burlinson Consultant Clinical Scientist based in the Laboratory who took time to kindly explain the process in more detail.
The Laboratory undertakes tests for children up to the age of 18 from the Royal Manchester Children’s hospital. For adults they undertake tests for patients’ from MRI, Blackpool, Oldham and the Greater Manchester feeder.
A stem cell or bone marrow transplant replaces damaged blood cells with healthy ones. It can be used to treat conditions affecting the blood cells, such as leukaemia and lymphoma.
Stem cells are special cells produced by bone marrow (a spongy tissue found in the centre of some bones) that can turn into different types of blood cells.
The three main types of blood cell they can become are:
red blood cells – which carry oxygen around the body
white blood cells – which help fight infection
platelets – which help stop bleeding
A stem cell transplant involves destroying any unhealthy blood cells and replacing them with stem cells removed from the blood or bone marrow.
Why are stem cell transplants carried out?
Stem cell transplants are used to treat conditions in which the bone marrow is damaged and is no longer able to produce healthy blood cells.
Transplants can also be carried out to replace blood cells that are damaged or destroyed as a result of intensive cancer treatment.
Conditions that stem cell transplants can be used to treat include:
severe aplastic anaemia (bone marrow failure)
leukaemia – a type of cancer affecting white blood cells
lymphoma – another type of cancer affecting white blood cells
myeloma – cancer affecting cells called plasma cells
certain blood, immune system and metabolic disorders – examples include sickle cell anaemia, thalassaemia, severe combined immunodeficiency (SCID) and Hurler syndrome
If a patient is diagnosed with cancer their Haematology Doctor may initially advise Radiotherapy or Chemotherapy treatment however if this is not an option or hasn’t helped then a stem cell transplant will be considered. The potential benefits of a transplant outweigh the risks and the patient is in relatively good health, despite your underlying condition.
The Doctor will send a blood samples for human leukocyte antigen (HLA typing) and serum samples for antibodies to the MRI laboratory for testing.
By carrying out tests on cells in our blood and examining our DNA, Scientists can find out what type of tissues we have. This will allow Doctors to decide how our body will react to new stem cells, which will be given by a transfusion.
These new stem cells migrate to the bone marrow, where they divide and eventually produce red blood cells. If the stem cells the patient receives are from another person, it is important that the patient’s tissue type match otherwise the patient may reject the transplanted stem cells, or the transplanted stem cells may react to the patient’s own tissue in what is termed “graft versus host disease”.
The best chance of getting a match is between two siblings (brothers and sisters who have the same mother and father). If brothers and sisters inherit the same tissue type from both parents they are said to be an identical match. Patients have a 1 in 4 chance of being matched with their sibling. When a Doctor decides that a stem cell transplant is the best treatment, they will first of all request to test your brothers and sisters or other family members to see if there is an identical match.
However, two unrelated people can just happen to be a good match too. If after testing the MRI laboratory is unable to find a match between brother, sister or close family they will start a search of the unrelated donor panel.
They will focus their search on the Anthony Nolan, British and Welsh bone marrow registers and the Bone Marrows Worldwide Register (BMWR) for potential donors.
There are about 28 million people worldwide registered with various donor organisations, across 54 countries on 98 registers.
Haploidentical Stem Cell Transplant
For patients who need a stem cell transplant but do not have a HLA-matched related or unrelated donor, recent medical advances have made possible the use of a partially matched or haploidentical related donor. A haploidentical related donor is usually a 50% match to the recipient and may be the recipient’s parent, sibling or child.
Stem cell donation
There are two possible ways of donating stem cells that you may be asked to consider.
The first, and most frequently used, is to donate stem cells from circulating blood. For the four days preceding the donation a nurse will inject the donor with a drug which vastly increases the number of stem cells in your circulating blood. On the fifth day the donor will have a blood test to check that you have enough circulating stem cells. The donor will then be connected to a cell-separator machine, without the need for a general anaesthetic. The machine collects the stem cells from the donor blood via a vein in one arm, returning the blood to the donor’s body through a vein in your other arm. If the donor is already a platelet donor you will be familiar with this type of machine. Occasionally the donor may be asked back on the sixth day for a further donation, if the dose of cells obtained is not sufficient. 9 out of 10 people donate their stem cells this way.
The second method is donation of bone marrow itself, which involves the removal of stem cells from the donor’s hip bones. This is done using a needle and syringe under a general anaesthetic in a hospital. Although this is not a surgical operation, there will be marks on the skin made by the needle. As there may be some discomfort where the needle has been inserted, the donor will need to stay in hospital for up to 48 hours and have a period of recovery at home of up to five days.
Another form of donation is called Cord blood donation. Cord blood donation is completely safe for the mother and baby. No blood is taken from your baby. It’s only taken from the umbilical cord itself after a baby is born.
Stem Cell Transplant
MRI Laboratory will request blood samples from the donor that’s been found on the appropriate register and compare these to the patient’s HLA. If a match is found they will report this to the patient’s consultant. At that point a stem cell transplant will be scheduled.
Stem cell and bone marrow transplants are a way of giving very high doses of chemotherapy. Sometimes the patient also has whole body radiotherapy (total body irradiation). The high dose treatment kills off the cancer cells in the body but also kills the stem cells that make blood cells in the bone marrow.
We need stem cells in order to survive. So after the high dose treatment, the patient has stem cells or bone marrow through a drip into your bloodstream. These cells make their way into your bone marrow and start to make blood cells again.
After the patient has finished all their treatment, they have their stem cells or bone marrow back through a drip. This is just like having a blood transfusion.
The cells flow through the patient’s central line into the bloodstream. They then find their way back into the bone marrow. Soon they start to make new blood cells and release them into the bloodstream. The patient will have regular blood tests to check when their bone marrow starts to make new blood cells.
Until the bone marrow starts making enough blood cells the patient is at risk of picking up infections. So they might be moved into a single room in the hospital ward to help protect them. They will stay in this room until their blood counts have come up. This might take a few weeks.
Overall the work of the Laboratory is similar to the work done for a solid organ transplant. They receive blood samples and carry out tests for Human leukocyte antigen (HLA) typing which is a protein – or marker – found on most cells in our body and is used to match us with a donor for bone marrow or cord blood transplant. The best transplant outcome happens when a patient’s HLA and the donor’s HLA closely match. They also carry out tests on serum samples for antibodies, which are produced by the body to fight infections. These tests combined with the HLA and DNA testing is used to find the right donor.
The slightly different approach is for the Laboratory to liaise with the various bone marrow registers to find the right donor match.
The research and work is very complex but without the work of the staff in the MRI Laboratory we probably wouldn’t be here to read this article.