Stem Cell Collection: Apheresis

apheresis machine
Machine for platelet apheresis

What Are Stem Cells?

Stem cells are immature cells that grow and divide into mature red blood cells, white blood cells, or platelets. The type of blood cell that a stem cell will develop into is determined by the specific needs of the patient's body, and through the stimulus of special substances called "growth factors."

Stem cells can be collected from the peripheral blood (a PBSC collection) and/or from the bone marrow via a bone marrow harvest.

What Is a PBSC Collection?

A PBSC collection is a procedure involving the separation and collection of a particular type of white blood cell from the peripheral blood.

The medical staff will set the apheresis system to collect a certain type of white blood cell called a mononuclear cell or MNC. The peripheral blood stem cells will be collected with these white blood cells. It is impossible to collect only the peripheral blood stem cells. There will be red blood cells and platelets mixed with the peripheral blood stem cell product.

Why Is a PBSC Collection Necessary?

A physician will recommend high dose chemotherapy as an appropriate treatment and potentially, a cure for a patient's disease.

However, high dose chemotherapy suppresses the ability of the bone marrow to make blood cells, and peripheral blood stem cells are needed to restore bone marrow function. Therefore, prior to the use of high dose chemotherapy, a prescribed number of peripheral blood stem cells will be collected and frozen for storage.

After the high dose chemotherapy is administered, the peripheral blood stem cells will be thawed and transfused back to the patient. The stem cells migrate to the bone marrow and begin the process of creating new blood cells.

How It Works

A PBSC collection is performed with a medical device called a blood cell separator, which uses a centrifuge to separate and collect mononuclear cells, including peripheral blood stem cells, from the blood. Before a PBSC collection procedure, the patient may receive a prescribed dose of chemotherapy and/or other drugs called growth factors. A common growth factor is Granulocyte Colony-Stimulating Factor (G-CSF), manufactured by Amgen under the name Neupogen®. These drugs will generally cause the release of a large number of peripheral blood stem cells into the blood stream. When the physician determines the white blood cell count has increased to a sufficient level, a series of PBSC collections will begin.

The latest technology blood cell separators accomplish all this in an automated, continuous and safe manner. The sterile tubing sets and needles are used only once and then discarded.

Common Patient Concerns

If the patient does not have a catheter, insertion of needles may cause some discomfort. It may be uncomfortable for the patient to remain still for the duration of the procedure. Patients may feel somewhat dizzy, cold or nauseous during the procedure. Afterward, they may feel tired. However, there should be no lasting effects. More than 25,000 PBSC procedures are conducted every year with few problems. The procedure usually takes two to four hours.

Dive Deeper

Online Resources

Information on Apheresis from the Indiana Blood and Marrow Transplantation program.

Follow this link to identify a conveniently located cancer treatment center and begin the process of enrollment.

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