Leukapheresis

Introduction

This patient information sheet is intended for:

• people donating lymphocytes after their peripheral blood stem cells have been harvested and used in a recipient transplant.
• patients whose lymphocytes will be used to manufacture CAR-T therapy for use as part of their own treatment.
• patients who need leukapheresis as an additional treatment that we may use to urgently treat certain leukaemias by reducing the number of white blood cells in your blood.

What are lymphocytes?

A lymphocyte is a type of white blood cell that works as part of the immune system. There are two main types of lymphocytes: T cells and B cells. These cells can be “harvested” from the blood using a technique called apheresis, which the blood is separated using a machine and the cells collected.

What are the lymphocytes used for?

Donor Lymphocyte Infusion

A donor lymphocyte infusion (DLI) uses lymphocytes from the original transplant donor to boost the immune system of the patient. This may be as part of the patient’s original treatment plan or be required additionally post stem cell transplant.

CAR-T Manufacture

Lymphocytes are collected by apheresis (leukapheresis) and sent to a specialist manufacturer to produce CAR T-cell therapy. The manufacturer grows the cells in a laboratory and labels the cells with a special receptor (called a chimeric antigen receptor (CAR)) which when infused back into the patient attacks the cancer cells. Chimeric antigen receptor T cells are cells that are genetically engineered (changed) in a laboratory by adding a manufactured CAR. The lab lets them multiply and grow. CAR-T cells are trained to bind to the cancer cells and destroy them when infused back into patient.

Do I need any tests prior to lymphocyte cell collection?

Yes. You will need to have a repeat medical assessment with the consultant and various investigations including blood tests, similar to your original medical assessment.

What does the lymphocyte harvest involve?

This treatment collects mononuclear cells (the group of cells that contain lymphocytes) which are naturally present in the blood. Harvesting lymphocytes is very similar to the collection of peripheral blood stem cells (PBSC), but unlike this, it does not require injections of Granulocyte Colony Stimulating Factor (G-CSF) to stimulate the bone marrow.

You will need to attend the Apheresis Unit (Ward E10) at Addenbrooke’s for the lymphocyte cell collection.

The procedure is performed in the Apheresis Unit by connecting your veins to a cell separator (‘apheresis machine’) by temporary insertion of two cannula needles in your veins. One IV line removes your blood, and the other returns filtered blood to your bloodstream. If a vein cannot be accessed with a regular IV line or multiple leukapheresis procedures are needed, a temporary central venous catheter may be placed in your neck or chest in a separate surgical procedure. This is done in advance of leukapheresis and takes between 45 to 60 minutes to perform (usually 24 hrs before apheresis and you will need to stay in the CUH provided accommodation post insertion).

This machine spins the blood and separates it into different parts. The machine can detect the cells that we wish to collect and put them into a bag. The rest is returned to you. During the procedure the machine will also collect plasma into a separate bag. If you wish you can see a cell separator machine when you attend for your outpatient appointment.

To prevent your blood from clotting in the cell separator an anticoagulant is added to it. This might cause temporary tingling or pins and needles in your fingertips or around your mouth. If this happens, let the nursing staff know.

When you arrive, we will take a further blood sample from you when inserting the cannula into your vein. Depending on the results, we may recommend a blood transfusion to replace red blood cells and platelets.

How long will lymphocyte collection take?

The lymphocyte harvest itself takes about five and a half hours. We aim to collect all we need in one harvest procedure.

Expect to be on the unit for six to six and a half hours.

You may wish to bring some entertainment such as music, downloaded programmes or films, to listen or watch but please use headphones.

Do I need to stay in hospital when the lymphocytes are collected?

No, you do not need to be admitted into hospital for the lymphocyte collection. This is an outpatient procedure. If you need a temporary apheresis line prior procedure, this will require an overnight stay in CUH on site accommodation.

Can I eat before or during the lymphocyte collection?

Yes, we would encourage you to eat a good breakfast before the collection and to continue eating and drinking as normal throughout the procedure. A lunch will be provided on Ward E10.

Can I bring a friend/relative with me for the procedure?

Yes, but just one other person, as the space on the apheresis unit is limited.

We would advise that you bring someone with you to drive you home after the procedure.

What to expect after the procedure?

After the procedure is complete, you will be asked to sit for a while to ensure that you are neither faint nor nauseous. Once the nurse is assured that you are OK, you can leave.

It is not uncommon to feel tired after leukapheresis. To get back on your feet faster, limit your activities for the first 12 to 24 hours. If you had an IV line placed in your arm, keep the bandages dry and in place for at least five to six hours before removing them.

How long are the lymphocyte cells kept?

Donor Lymphocyte Infusion

The harvested lymphocytes will be counted and divided into several (usually four) doses.

The first dose is usually given to your recipient ‘fresh’. The remaining doses will be frozen until needed.

Your recipient will be reassessed at three-monthly interviews to determine if the remaining doses are required.

The harvested cells can be stored frozen for several years at very low temperatures, but we cannot keep the cells indefinitely. With your permission, your doctor will decide to dispose of the cells if/when your recipient no longer requires the lymphocyte treatment.

CAR-T Manufacture

Unlike many other blood cancer drugs, CAR-T therapy is designed to be an individualized one-time treatment.

The lymphocytes are sent to the specialist manufacturer and the resulting CAR-T therapy is stored frozen until it is infused. CAR-T product will be disposed of if not infused within 12 months for various reasons, such as disease progression and not further eligible.

If the cells are not needed, could they be used for research?

Donor Lymphocyte Infusion

Yes. However, to allow the haematology team to do this, you will need to give us your permission on the harvest consent form. This form will be kept in your medical notes. The cells would only be used for research if they were to be otherwise destroyed.

Where the stored cells are not be used for treatment, they may be used for research purposes rather than be discarded if your consent has been obtained in accordance with the requirements of the Human Tissue Act 2004.

Tissue from the living may be stored for use and/or used without consent, provided that:

• the research is ethically approved.
• the tissue is anonymised so that the researcher is not in possession of information identifying the person from whose body the material has come and is not likely to come into possession of that information.

CAR-T Manufacture

Unused CAR-T product cannot be used for research purposes.

Please note:
You will be asked to sign the harvest consent form before the cell collection can go ahead.