Collection of stem cells from your blood : University College London Hospitals NHS Foundation Trust

This page explains what stem cells are and how they are collected from your blood. It includes information about what happens before, during and after the collection, and how the cells are stored. If you have any questions about the stem cell collection or about the information on this page, please talk to your doctor or nurse.

You may hear your healthcare team refer to stem cells as haematopoietic progenitor cells (HPC).

Stem cells are blood cells at a very early stage of development. They can divide and develop into any of the three main types of blood cells:

Red blood cells, which carry oxygen to all cells in the body
White blood cells, which help to fight the bacteria and viruses that cause infection
Platelets, which help blood to clot and prevent bleeding.

Collection of stemm cells 1.png — **Image produced by Lymphoma Action and reused with permission**

Stem cells are formed and develop into blood cells in the bone marrow, which is spongy tissue inside the bones. Once the blood cells are fully mature, they are released into the bloodstream. Only a very small number of stem cells can be found in the blood.

To collect your stem cells, we need to move them from the bone marrow into your blood. This is called peripheral blood mobilisation and we will refer to it on this page as mobilisation. Once the stem cells are in the blood we will collect (harvest) them by a procedure called apheresis. Apheresis simply means removal or extraction.

One of the treatment options available to you in the future is high-dose chemotherapy. This can be either alone or in combination with radiotherapy. This type of treatment aims to kill cancer cells. But the high doses of chemotherapy and/or radiotherapy also damage the healthy stem cells. This in turn makes the blood cell counts very low.

Depending on the amount of chemotherapy and radiotherapy you have, it may take many weeks for your bone marrow and stem cells to recover. The longer it takes for your bone marrow to recover, the longer your blood cell counts will be low. This will make you prone to infections, bleeding and anaemia.

By collecting your stem cells before your high-dose treatment, we rescue them from being damaged. We can then return them into your veins via a drip a day or two after the treatment. The stem cells go to the bone marrow and start to develop into the different blood cells you need. This is called an autologous stem cell transplant (or autograft). For more information about the transplant, read our page ‘A guide to autologous stem cell transplant’.

When you and your consultant decide to go ahead with high-dose treatment, a stem cell transplant clinical nurse specialist (CNS) will organise your stem cell collection. This will include arranging any tests or treatment you may need before the collection.

The CNS will explain in detail what this process involves and you will have a chance to ask questions. They will also give you a contact number to call if you have any problems or questions at a later date.

The CNS will talk to you about:

Pre-collection tests
Consent to carry out the treatment
Treatment you may need before the collection, including a routine dental check-up
Mobilising the stem cells
Blood tests needed during the mobilisation
Assessing your veins
Collecting and storing your stem cells
Fertility and contraception.

Once all the tests have been carried out or booked, you will receive a timetable outlining the different procedures you will need before and during the mobilisation. This will also include provisional dates for your stem cell collection.

Please inform the CNS if:

you are taking medicine that thins your blood, or
you have had any previous radiotherapy treatment.

You will have various tests to make sure you are fit enough to
undergo stem cell mobilisation and collection. These will include:

Blood tests

Full blood count – to check your haemoglobin, white blood cells and platelets
A blood test to check your liver and kidney function
A blood test to determine your blood group
Blood tests to check for some infectious diseases, such as Hepatitis B, Hepatitis C, HIV, syphilis and HTLV. It is a legal requirement in the UK that these tests are carried out and the results known before we collect and store the stem cells. This is to prevent infection spreading to healthy cells during storage. By doing these tests we are not implying that you have these viruses.

Bone marrow biopsy (where relevant)

The bone marrow biopsy checks for any disease in your bone marrow. It will be done either at your local hospital or the transplant centre.

Re-staging scans (where relevant)

Re-staging scans (such as PET, CT or MRI scans) assess your response to your latest treatment. Depending on your scan results, you may need further tests or treatment before having the high-dose therapy.

The stem cell transplant CNS will ask you to sign a consent form to undergo stem cell mobilisation and collection. This will confirm that you agree to have the procedure and understand what it involves. They will answer any questions you may have so please ask if anything is unclear.

Mobilisation is done in one of the following ways:

Combination of chemotherapy and injections of growth factor G-CSF, or
G-CSF injections alone.

G-CSF stimulates the growth of stem cells in the bone marrow. It also helps to release the mature blood cells into the blood circulation.

If you need both chemotherapy and G-CSF injections, you will have either:

A course of treatment chemotherapy followed by daily injections of G-CSF, or
A single dose of cyclophosphamide chemotherapy followed by G-CSF injections.

Treatment chemotherapy aims to further reduce your disease if it is still present after your initial treatment. The course of chemotherapy will be followed by daily G-CSF injections. The number of G-CSF injections will depend on the chemotherapy used, but it usually is 8 to 11.

Cyclophosphamide chemotherapy is suitable for people whose disease is in remission or stable. It is given over a couple of hours in a day care setting followed by 8 to 10 days of G-CSF injections.

As your white blood cell count recovers following the combination of chemotherapy and G-CSF injections, your stem cells will move (mobilise) from the bone marrow into the blood. These stem cells can then be collected or ‘harvested’.

Some people need plerixafor injections in addition to G-CSF to help with their stem cell mobilisation.

Plerixafor increases the number of stem cells in your bloodstream. It does this by helping to release them from the bone marrow.

Your consultant and your stem cell transplant CNS will advise you on the type of mobilisation that is best for you. They will also tell you if you need plerixafor injections.

G-CSF is a substance produced naturally by the body. Its major function is to turn stem cells in the bone marrow into mature blood cells. When given at higher doses than the body produces, G-CSF also helps to move some of the stem cells in your bone marrow into your bloodstream.

What will the G-CSF injections do?

After a number of G-CSF injections, your white blood cell count will rise and your stem cells will mobilise from the bone marrow into the blood. Your stem cell transplant CNS will mark on your timetable when you can expect this to happen.

It’s very important that you don’t miss any of your G-CSF injections. If you do, there is a risk that there may not be enough stem cells in the blood for us to collect them.

Are there any side effects of G-CSF injections?

Yes, there are some side effects of G-CSF injections, with the most common ones including:

Back pain
Flu-like symptoms
Headaches.

These are temporary and will go away once you finish your course of injections. Paracetamol tablets (two tablets = 1g) should help to ease these symptoms. You can take a maximum of eight tablets (4g) in 24 hours (two tablets every six hours). If paracetamol is not helping or your symptoms get worse, contact the stem cell transplant CNS for advice.

You must not take aspirin, aspirin-containing or aspirin-like medicines, such as ibuprofen (Nurofen®), while you are having G-CSF injections. This is because your platelet levels may be lower than normal and you may be at a higher risk of bleeding. If you take aspirin for other medical reasons, please discuss this with your CNS.

Very rarely an allergic reaction can occur. Go to your local Emergency Department (A&E) without delay if you experience any of the symptoms listed below:

Itching
Rash
Rapid heart rate
Dizziness
Shortness of breath.

A serious but extremely rare complication of G-CSF is spleen enlargement and rupture. If you experience any tenderness in the upper left side of your abdomen, just underneath your rib cage, go to your local Emergency Department (A&E) immediately. You should also contact us on 07852 220900.

How is the G-CSF given?

The G-CSF injections are given under the skin, usually in the abdomen, thigh or arm. They can be administered by:

Yourself
A family member
A district nurse, or
A nurse at your local hospital or UCLH.

If you or your family want to administer the injections, a nurse will teach you how to do them. We recommend that the injections are done at the same time each day. If your G-CSF needs to be stored in your fridge at home, take the injection out 20 minutes before it is due. It should sting less.

What will the plerixafor injections do?

Plerixafor increases the number of stem cells in your bloodstream by helping to release them from the bone marrow.

How is the plerixafor given?

Plerixafor is given as an injection under the skin, usually in the abdomen, thigh or arm. The injections must be administered by a nurse at UCLH.

Are there any side effects of plerixafor injections?

The most common side effects are:

Nausea
Vomiting
Diarrhoea
Tiredness
Headache
Dizziness
Joint pain.

These are temporary and usually disappear within a few hours of administration.

Very rarely, you may experience:

Allergic reaction causing symptoms such as rash, swelling around the eyes, shortness of breath and feeling faint
Pain in the upper left abdomen or at the tip of your shoulder
Chest discomfort.

If any of the above occur, go to your local Emergency Department (A&E) and contact us on 07852 220 900.

You will have regular blood tests throughout the mobilisation. They will help us to identify when the stem cells are likely to be in your bloodstream. This is usually when the white blood cell count increases rapidly. We can estimate the day of this increase and we will include it in your timetable.

If you need blood tests before the collection, your stem cell transplant CNS will tell you when and where these will take place. The results will be available to the nurses at the transplant centre who are going to carry out the collection.

Your stem cell collection will take place in the Apheresis Unit, 4th Floor University College Hospital Macmillan Cancer Centre.
First, you will have a blood test to check if your blood count has reached a certain level and we can carry out the collection. If it hasn’t, you will need to go home to have another injection of G-CSF and return the next day for a blood test.
The collection of your stem cells will be done using a procedure called apheresis. During apheresis, a constant flow of blood will be taken from your bloodstream, passed through a machine called a ‘cell separator’, and then put back into your bloodstream.
The stem cell transplant CNS or an apheresis nurse (a nurse who will carry out the collection) will assess the veins in your arms. This is to make sure that they are suitable for the stem cell collection.
If your veins are big enough, you will have two needles. The larger needle will be placed in your non-dominant arm (the arm that you don’t write with), if possible. You will have the smaller needle in the other arm. During the collection, blood will be taken from the larger needle into the cell separator. The cell separator will separate the blood into the different types of blood cells. It will collect the stem cells into a collection bag and return the rest of your blood to you via the smaller needle.
If your veins are not big enough, we will insert a special catheter into the large vein at the top of your leg. The catheter is a thin, semi-rigid tube called a vascath. It will allow a constant flow of blood to be taken from and returned to your bloodstream. You will have local anaesthetic (pain relief) to have the vascath inserted in day care. It will remain in place until we have collected enough stem cells. This may mean keeping it in overnight for the second day of collection. If this is the case, you will need to be admitted to hospital.
Please note that we do not use a PICC or Hickman line that you may already have in place for the collection.

Preparing the cell separator

An apheresis nurse will prepare the cell separator for the collection. They will stay with you throughout the procedure, which will take about four to five hours. You will need to stay fairly still on a reclining bed during this time.

The nurse will fit a sterile kit into the cell separator. This will protect your blood from outside infections during the collection.

Once the two lines from the kit are attached to you, the nurse will enter your height, weight and your morning blood test results into the cell separator control panel.

How much blood will be in the cell separator?

The amount of blood in the cell separator at any time is less than 250ml (less than a small glass of water). The volume of blood cells taken from you by the end of the procedure is no more than 200ml.

What is ACD-A?

As the blood enters the cell separator, a drug called ACD-A is added to it. ACD-A stops the blood from clotting while it is going through the cell separator.

Are there any side effects that can occur during the collection?

Yes, the most common side effects are caused by ACD-A.

What side effects does ACD-A cause?

You may feel sick or you may develop a tingling sensation in your lips and nose or fingertips. The side effects are usually short-lasting and should stop once you have some calcium supplements. These could be chewable calcium tablets or a calcium infusion.

If you experience any of these side effects it’s important that you tell your nurse straight away. They will help to relieve these symptoms very quickly. It may also be a good idea to have a milky breakfast before the collection.

Why does ACD-A cause side effects?

The blood would naturally clot within the abnormal environment of the cell separator. As calcium helps the blood to form clots, ACD-A is used to absorb the calcium from the bloodstream and prevent the blood from clotting. This lowers the calcium levels in the blood and may cause side effects.

What other side effects or problems can occur?

As your blood pressure drops during the collection, you may feel light-headed, especially at the beginning. Please let your nurse know if you experience this.

It’s also sometimes difficult to get enough blood to flow from the veins in your arm. Your apheresis nurse may need to adjust the position of the needle to allow a better flow. This should not be painful but please tell the nurse if you feel any discomfort.

What can I do during the collection?

You will need to remain in bed or seated for the entire time the collection takes (four to five hours). It is a good idea to bring something to read or a tablet/laptop that can help you pass the time. Wear loose-fitting clothes so you are comfortable throughout the collection. You will be able to eat and drink as normal.

What happens when the collection has finished?

Your apheresis nurse will disconnect you from the cell separator, dispose of the kit, and take the stem cells to the laboratory. You will have a blood test to check your full blood count. After that you will be free to get up and move around.

What happens to the collected stem cells?

Your stem cells will be counted in the laboratory to check if we have collected enough. The result will be available about one hour after the collection has finished. You will need to wait in the Apheresis Unit until all your test results are back.

The cells are then frozen (cryopreserved) in the laboratory until you need them for your treatment, or until they can be disposed of (see here for more information).

What happens if enough stem cells have been collected?

You will be able to go home. If you have had a vascath inserted, the nurse looking after you will remove it before you leave.

What happens if we haven’t collected enough stem cells?

You will have another dose of G-CSF and possibly plerixafor. A further stem cell collection will take place the next day.

If we haven’t collected enough cells after the second or third day, we will arrange an appointment with your consultant. They will discuss this with you and advise if you may still be able to go ahead with your transplant.

Collection of stem cells from your blood 2.png — Photo courtesy of Canva.com

The cells may not be used in a transplant as planned for a variety of reasons. For example:

There may not be enough cells to proceed to the transplant.
The cells may be unsuitable for clinical use (for example if there is infection in them).
There may be a clinical reason why you don’t proceed to the transplant as planned.

Cells which don’t carry a risk of transmitting infection will be stored frozen, usually for a maximum of five years. This can be less if they are no longer needed or are unsuitable for clinical use.

After five years, they may be considered for routine disposal once the relevant consultant(s) have reviewed your records. If they are approved for disposal, this will be done following national and/or EU regulations for the disposal of biohazardous materials.

Sometimes the stem cells that have been approved for disposal are still considered fit for storage and clinical use. You will then have the right to transfer the cells to a storage facility outside of UCLH. In this case, we will not be responsible for storing your cells. During the consent process we will ask you if you would like us to contact you if this happens. Please keep us up to date with your current address and contact number. You will also have the opportunity to discuss this further.

If the collected cells are carrying a potentially transmissible infection, they will be stored in a separate facility for at least 12 weeks, unless they are no longer required or prove unsuitable for clinical use. From 12 weeks, they may be considered for disposal, as described above.