Blood & Marrow Transplant

Key points about blood and marrow transplants

• during a blood and marrow transplant (BMT), doctors replace your child's bone marrow system with healthy blood stem cells
• your child may need a BMT because they have too few blood stem cells, their blood cells do not work properly or as part of their cancer treatment
• healthy stem cells can come from bone marrow, circulating (peripheral) blood, and cord blood

What is a blood and marrow transplant?

During a blood and marrow transplant (BMT), doctors replace your child's bone marrow system with healthy blood stem cells.  These stem cells are young, immature cells that grow into more specialised, mature blood cells. During the transplant, your child's bone marrow absorbs the healthy stem cells. Once inside the bone marrow, the cells start to produce healthy blood cells. This process is called engraftment.

What does bone marrow do?

Our bone marrow produces blood cells called red blood cells, platelets, and white blood cells.

Read more about blood tests and blood counts

Inside the marrow, blood cells start off as young, immature cells called stem cells. Once they develop, blood cells do not live for a long time inside our bodies. This is why our marrow continuously produces all 3 types of blood cells to keep us healthy.

Why is my child having a blood and marrow transplant?

Your child may need a BMT because:

• they have too few blood stem cells
• their blood cells do not work properly
• it is part of their cancer treatment
• their cancer has relapsed and it is part of their immunotherapy

What are the types of transplants?

There are 2 types of transplants:

Allogeneic stem cell transplant

In an allogeneic stem cell transplant, your child receives stem cells from a donor.  In many cases, the donor is a family member, such as a sibling.

Autologous stem cell transplant

In an autologous stem cell transplant, your child donates their own blood stem cells.

Where do blood stem cells come from?

Healthy blood stem cells can come from 3 different parts of our body:

Bone marrow

The spongy tissue inside our bones is called bone marrow. We have blood stem cells inside the marrow of our:

• breastbone
• skull
• hips
• ribs
• spine

Our bone marrow contains the largest amount of stem cells in our body. To collect blood stem cells directly from the marrow, the donor will be asleep - they will have a general anaesthetic. Doctors then inject a needle into the top of the hip bone and harvest stem cells directly from the bone marrow.

Circulating (peripheral) blood

Your child's healthcare team can also collect donor blood stem cells indirectly from the blood that circulates in our body. This is called a peripheral blood stem cell harvest. The protein moves the blood stem cells from the marrow into the bloodstream. The healthcare team then harvest the stem cells using an apheresis machine. This machine can separate the stem cells from the donor's blood.

Cord blood

Doctors can also collect blood stem cells from the umbilical cord, which connects a baby to their mother's placenta. The healthcare team collects them from the umbilical cord and placenta after the baby is born.

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