What is a Peripheral Blood Stem Cell Transplant?

A peripheral blood stem cell transplant (PBSCT) is a procedure in which a person’s stem cells are harvested from their blood and then intravenously infused into the bone marrow. The donor can be the person receiving the transplant or another person. Stem cells are special cells in the body that do not die off after dividing many times. These cells can become many other cells, such as white blood cells, red blood cells, and larger cells called megakaryocytes that produce platelets to aid in the clotting of blood. The goal of the stem cell transplant is to replace the immune system.

Patients who receive a peripheral blood stem cell transplant are typically those who have completed chemotherapy and radiation treatments. The purpose of the peripheral blood stem cell transplant is to replace the cells destroyed by the cancer treatment and reactivate the immune response. The small number of stem cells transplanted can repopulate the entire bone marrow with healthy cells.

The process to obtain the stem cells is called apheresis. The amount of stem cells available for harvest is increased when daily injections of a medication called granulocyte-colony stimulating factor are given for four to five days prior to the procedure. The donor is attached to a machine that filters the stem cells out of the blood through a large vein in the neck, chest, or groin area. The machine then returns the blood to the donor and the collected stem cells are stored and then frozen. The apheresis process normally takes four to six hours.

After a peripheral blood stem cell transplant, the stem cells will be carried to the bone marrow to begin a process called engraftment. The engraftment process produces more platelets and white and red blood cells for use by the body. It takes about two to four weeks for the stem cells to begin making new cells. The immune system can be fully functional in as little as one year, or it may take as long as two years for the immune system to recover.

Side effects of the peripheral blood stem cell transplant are usually short-lived and include nausea, vomiting, and fatigue. A small number of patients have reported hair loss, mouth sores, and skin rashes. Antibiotics may be prescribed to prevent bacterial infections at the time of the transplant and be continued until test results show a positive immune response.

Physicians test the effectiveness of the peripheral blood stem cell transplant through a process called bone marrow aspiration. A long needle is inserted in the marrow of the bone, usually through the hipbone, and a small amount of the marrow is collected and sent to the lab to be evaluated. The laboratory technicians will count the available cells and determine the functionality of the bone marrow.