What are stem cells?
Blood originates from stem cells in the bone marrow. Stem cells divide and differentiate, giving rise to all the cellular components of blood: red cells, leucocytes and megakaryocytes, the precursor cells of platelets. Healthy blood stem cells can be collected from three sites: bone marrow, blood stream and placental blood (cord blood).
Stem cells are collected from adult donors directly from the marrow inside bones using a needle and syringe. Stem cells can also be harvested from the blood stream using special apparatus, following growth factor treatment which brings about the release of stem cells from bone marrow into circulating blood. Placental blood, the third source of blood stem cells, is the extra blood remaining in the placenta after childbirth. This blood is rich in stem cells but is usually lost when the placenta is disposed of after delivery.
Why are stem cells collected?
Bone marrow function is disrupted in malignant blood disorders. The intensive chemotherapy and radiotherapy used to treat these diseases further damage the bone marrow and its stem cell production. Stem cells obtained from a healthy donor can be used to replace the patient's diseased and damaged bone marrow.