Peripheral Blood Stem Cell Harvest

A peripheral blood stem cell harvest is a technique used to restore a person's blood cells after they have been damaged by chemotherapy or radiation. The procedure is often used to treat patients with either leukaemia or lymphoma cancer. Because the chemotherapy or radiation treatment damages healthy cells alongside cancer cells a patient requires a viable source of blood-forming cells. Stem cells are able to generate the white blood cells, platelets and red blood cells that are important for functions such as oxygen transport, clotting and immunity.

What Types Are There?

There are three types of transplants that may be performed for a peripheral harvest:

• Autologous: a patient receives his or her own stem cells.
• Allogeneic: a patient receives stem cells from someone else-either a relative or an unrelated donor.
• Syngeneic: a patient receives stem cells from an identical twin.

How Are The Peripheral Blood Stem Cells Obtained?

The stem cells utilised in this procedure are obtained from the bloodstream in a process called apheresis. In the preceding week before apheresis is performed, a donor receives drugs to increase the number of stem cells in his or her bloodstream. During apheresis, the donor's blood is removed, usually through the arm, and it flows through a machine that removes the stem cells. The blood then flows back to the donor while the extracted stem cells are then frozen until they are transferred to the recipient. The process usually lasts approximately five hours.

How Are Peripheral Blood Stem Cells Given To The Patient?

The patient is treated with either radiation or strong cancer drugs, before receiving stem cells through an intravenous line. After the stem cells are transplanted into the patient, they move from the bloodstream to the bone marrow. It is here that they produce healthy white blood cells, red blood cells and platelets. The process is called engraftment and it generally occurs over the two to four weeks following stem cell transplantation. Physicians will follow a patient's progress by observing blood counts on a regular basis to ensure that the engraftment is successful. A complete recovery is much more long-term, however, and immune functioning can take months to years before it is fully recovered. Sometimes, bone marrow aspiration is performed, where a physician samples a small amount of bone marrow to provide a detailed assessment of the patient's progress.

Advantages of Peripheral Blood Stem Cell Harvest

Although traditionally, all stem cell transplants that were initially performed were bone marrow transplants, peripheral blood stem cell transplants are now commonly used. It is often the case that more stem cells can be harvested from peripheral blood as opposed to bone marrow. In addition, the procedure for extracting cells from the donor is less taxing and complicated than a bone marrow stem cell harvest. Even more beneficial is the fact that the recipient's blood count tends to replenish much more quickly in comparison with a bone marrow harvest.

Therapies such as peripheral blood stem cell harvests are often life-saving. For those who have suffered from cancer or know someone who has battled the disease, stem cell treatments have provided a better chance of remission from the disease. Further research into new treatments as well as improving older ones will ensure that we stay on the path to a cure for cancer.