You’ve probably heard some people say that they’re having a bone marrow transplant and others say they’re having a stem cell transplant, but what’s the difference between those two things?

Let’s start with a few definitions.

Bone marrow

Bone marrow is a spongy substance in the centre of bones that produces blood cells. There are many kinds of blood cells (broadly speaking red blood cells, white blood cells, and platelets) but every type of blood cell starts out as a stem cell.

Stem cells

“Stem cell” is an umbrella term used to refer to cells that can divide and create new cells, but some stem cells are limited in the type of cell they can become. Blood stem cells (also called haematopoietic stem cells) are the stem cells that later develop into mature blood cells. It’s these stem cells that are found in bone marrow.

Bone marrow transplant

“Bone marrow transplant” is a general term that is used to mean any type of transplant of blood stem cells, regardless of where those cells are from: bone marrow, peripheral blood, umbilical cord blood.

How are stem cells collected?

While it is true that sometimes blood stem cells are harvested through taking some bone marrow from the donor, these days the most common way to collect (or “harvest”) stem cells is from the peripheral blood supply.

When blood stem cells are harvested this way, the donor is given drugs that stimulate the production of blood stem cells, pushing them into the blood stream in great numbers. The donor is then connected to an apheresis machine. The process is much like giving blood: a needle is inserted into a vein on the donor’s arm. Instead of collecting whole blood, though, the apheresis machine collects only the blood stem cells and the rest of the blood is returned to the donor through another tube.

These stem cells are bagged and either used fresh, or they are frozen until the recipient is ready for their transplant.

Who can donate stem cells?

We currently don’t have enough registered bone marrow donors in Australia. There are a few medical restrictions, but generally if you are between the ages of 18-30 then you are in the ideal age bracket to become a donor. However, you are still able to register to be a donor up until the age of 35. Once you’re on the register, you remain eligible to donate blood stem cells until the age of 60.

Becoming a stem cell donor is as easy as a cheek swab. Find out more about registering as a donor on the Strength to Give website.