Volunteers can donate Bone Marrow or Stem Cells by joining national registries. What does donating Stem Cells or Bone Marrow involve?

According to the latest figures from Bone Marrow Donors Worldwide (BMDW), there are just under 12 million people registered as potential bone marrow or hematopoietic blood stem cell donors worldwide.

What are blood stem cells? Why do they help? How are a donor and patient 'matched'? What does voluntarily donating stem cells or bone marrow involve?

What Are Hematopoietic Stem Cells (HSC)?

The term ‘stem cell’ is used for embryonic – the original cells of the unborn child – and for adult stem cells.

In the voluntary setting of stem cell donation, the hematopoietic (blood-forming) stem cells donated are adult stem cells and never embryonic stem cells.

Adult blood stem cells do not have the ability to change into different cells as required by the body, which is a characteristic of embryonic stem cells. However, they are able to differentiate into red and white blood cells and platelets.

If blood stem cells are not functioning correctly, too many or too few red or white cells or platelets are produced.

Mature blood stem cells need to be continually replaced as they only have a limited life span, and blood stem cells reproduce to supply the body with a continuous supply of functioning blood cells.

What Diseases Can Blood Stem Donations Cells Help?

The most common disease of the bone marrow comes under the banner of leukaemia. Leukaemia can be classified as either chronic or acute but there are also subcategories of the disease.

There are malignant diseases such as lymphomas and myelomas and various functional disorders of the hematopoietic system, for example, anaemia and immune deficiencies.

For a number of patients, being transplanted with healthy blood stem cells from volunteer donors is their only hope of a cure.

How is a Donor ‘Matched’ with a Patient?

Genes are inherited from our parents, and a sibling has an approximately 25% chance of being a compatible match for his brother or sister. This form of donation is known as a related donation.

Patients without a matching family member will rely on a suitable unrelated donor being found.

The search for a donor begins with the transplant centre forwarding the patient's tissue typing details to the national and international registries of volunteer donors.

These registries obtain their donor’s tissue types by performing a blood test to determine the Human Leukocyte Antigen (HLA) markers, which the immune system recognises. Three antigens are inherited from the Father and three from the Mother.

If there are initial signs of compatibility with the patient, further tests are performed to determine whether the match is good enough to proceed to donation.

What Is Involved in Donating Bone Marrow or Stem Cells?

Bone Marrow

• The donor will undergo a full medical examination prior to donation to ascertain his fitness to donate.
• He will attend the collection centre the day before the scheduled donation.
• The marrow will be extracted under general anaesthetic from the iliac crests around the pelvic area by specialist doctors using needle and syringe.
• The procedure could take between one to two hours.

Hematopoietic Blood Stem Cells

• The donor will undergo a full medical examination prior to donation to ascertain his fitness to donate.
• Five days prior to donation, the donor will begin a course of injections of a growth factor to stimulate the stem cells and pass them into the peripheral blood.
• The donor donates through a procedure known as apheresis. The donor has a needle in each arm throughout the collection. The blood is taken from one arm and passed through a cell-separating machine, which collects the mobilised cells, and the red cells are returned to the donor via a needle in the other arm.
• The procedure can take between two to four hours and may extend into a second day.

Further information about the procedures of bone marrow and stem cell donation and details of how to register as a potential donor can be found through the Anthony Nolan Trust and National Marrow Donor Program.