Transplant Basics

Why people need a Stem Cell/Bone Marrow Transplant (SCT/BMT)

There are many diseases which can damage or destroy bone marrow. Some diseases can cause blood cells to change shape, while others can stop some blood cells from maturing leaving them unable to carry out their intended function. Some types of cancers cause specific blood cells to multiply out of control, crowding out other healthy cells again leaving them unable to do their job. When these things happen people become sick.

Thankfully, in many cases patients are successfully treated with a combination of chemotherapy or radiotherapy, but for others a stem cell or bone marrow transplant can be the only treatment option.

What is a Stem Cell/Bone Marrow Transplant?

A stem cell or bone marrow transplant is a treatment where a patient’s sick or diseased bone marrow is replaced with new, healthy bone marrow. The patient is given a high dose of chemotherapy, and sometimes radiation therapy, to destroy the damaged bone marrow. Healthy stem cells are then infused into the patient’s blood stream and make their way to the bone marrow  where they replicate and develop into new blood cells. The patient now has a brand new immune system.

The healthy stem cells either come from a matched donor or from the patient themselves. If the stem cells come from a donor it’s called an allogeneic transplant, sometimes known as an allograft transplant, where ‘Allo’ means ‘other’. If the stem cells come from the patient it’s known as an autologous transplant, sometimes called an autograft transplant, where ‘Auto’ means ‘self’.

The ultimate goal of every stem cell or bone marrow transplant is to replace the patients damaged stem cells with new healthy ones.

What is the difference between a Bone Marrow Transplant and a Stem Cell Transplant?

For the patient there is absolutely NO difference between a bone marrow transplant and a stem cell transplant – they are exact same thing. They still receive healthy stem cells in the same way. The only difference between the two relates to where the stem cells are collected from.

Stem Cell Transplants (SCT), or Peripheral Blood Stem Cell Transplants (PSCT)

For 90% of donors, stem cells are collected from the donor’s blood stream. The donor is given a daily injection over four days of a hormone-like substance called G-CSF (granulocyte colony stimulating factor). This causes the bone marrow to overly produce stem cells which then leak into the blood stream. On day five the donor is connected to a machine called an apheresis machine which separates the stem cells from the rest of the blood. The donor has a needle in each arm – the blood flows out of one and into the machine where the stem cells are removed, and the rest of the blood is returned through the needle in the other arm. Apart from being pricked with a needle in each arm the procedure it pretty pain-free, although it can be a bit boring as you can be stuck there for 4 to 5 hours so bring a friend or your iPad.

Jordan donating stem cells for the Anthony Nolan Trust

Jordan donating stem cells for the Anthony Nolan Trust

Bone Marrow Transplants (BMT)

For the remaining 10% of donors, doctors may request the stem cells be collected from the hip using a needle and a syringe. You will be admitted to hospital and be given a general anaesthetic so don’t worry, you’ll be out for the count. The procedure will usually take an hour however you may need to stay in the hospital overnight so they can keep an eye on you – as they would with anyone needing a general anaesthetic. Doctors will generally only request this method of donating if the patient is a child or if the type of disease being treated has a better outcome for the patient.

Either way, as a donor you will always have the opportunity to ask questions and make sure you are comfortable with the donation method, but at the end of the day the choice is yours.

Types of Bone Marrow/Stem Cell Transplants

There are two main types of transplants:

  • Autologous, or Autograft transplants – this is where the patient is able to use their own stem cells. Healthy stem cells are collected prior to treatment and then transplanted back after chemotherapy.
  • Allogenic, or Allograft transplants – this is where the stem cells are donated from someone else. This can be further broken down into the following types of donors:
    • Matched Related – using stem cells from a brother or sister who have a matching tissue type
    • Matched Unrelated – using stem cells from a total stranger with a similar tissue type
    • Haploidentical Transplant – here the donor is a family member but not a perfect match. Stem cells come from a brother or sister, a parent or a child as the all have at least a 50 percent tissue match.

Diseases treatable with a stem cell or bone marrow transplant

The first bone marrow transplant was carried out by Dr E Donnall Thomas way back in 1956 to treat a patient with leukaemia. Although considered radical at the time, it paved the way for transplants to become a standard treatment option for many diseases, not just blood cancers. Stem cell transplantation in increasingly being used to treat more and more diseases including autoimmune diseases such as Multiple Sclerosis (MS).

Across Australia and New Zealand over 2,000 transplants are performed each year. Around two thirds of these are autologous transplants where the patients are able to use their own stem cells, but the remaining patients need an allogeneic transplant which rely on finding a compatible donor, someone registered on one of the world’s donor registries.

In 2017 the Australian Bone Marrow Transplant Recipient Register (ABMTRR) published information showing which diseases were treated using donated stem cells:

  • 56% of transplants were used to treat a range of leukaemia’s such as acute lymphoblastic leukaemia (ALL), acute myeloid leukaemia (AML) and chronic myeloid leukaemia (CML)
  • 18% of transplants treated blood stem cell disorders such as myelodysplasia (MDS)
  • 12% of transplants treated Hodgkin and Non-Hodgkin lymphomas
  • 3% of transplants were to treat multiple myeloma
  • The remaining transplants treated a range of immune deficiencies and other diseases

Around the world more than 50,000 stem cell transplants are carried out each year and this number continues to rise as doctors and researchers find more and more diseases which can be treated with stem cell transplants.