Stem cells are cells that are born in the bone marrow and later develop into one of the following:

• red blood cells

• white blood cells

• platelets

How does it work?

• With a stem cell transplant, cells are taken from your blood before chemotherapy and then later returned after chemotherapy (much like a Bone Marrow Transplant).

In some cases a patient will receive their own stem cells back, taken prior to treatment (this is called an autologous transplant) and in others a patient will receive cells from a donor (this is called an allogeneic transplant).

• We don’t have many stem cells circulating around in our blood, so a few days before the stem cells are taken an injection called G-CSF is given to increase their numbers.

• They are then collected by a procedure called leukopheresis, which filters the stem cells out of the blood through a machine over about 4 hours.

• After a high dose of chemotherapy is administered, the cells are transfused into the body (much like a blood transfusion). They will find their way back into the bone marrow (clever little things!), eventually resulting in normal blood cell numbers.

Allogeneic transplants

• If you are having an allogeneic transplant you will be given special drugs called immunosuppressants before, during and after the transplant, to stop your body rejecting the new cells.

They also help to suppress the 'new' (donor's) immune system to reduce the chance of GVHD and prevent it from causing serious problems in the body.

• It can take a year or even longer for the immune system to fully recover following an allogeneic transplant.

As such, there’s a risk of infection for some time after your transplant. It’s important to take some sensible precautions to prevent infections during this time (for example avoid contact with people with people who are sick).