We obtain stem cells from donors by collecting bone marrow, peripheral blood stem cells or umbilical cord blood. The easiest method is cord blood collection. A baby's umilical cord is usually thrown away after the baby’s birth. Cord blood is especially rich in stem cells. Many parents donate their babies’ cord blood to cord blood banks.

The other two collection methods—bone marrow and peripheral blood—collect cells directly from a donor. What stem cell source we use depends on the patient’s disease and other factors.

Harvesting Bone Marrow Stem Cells
Bone marrow is full of stem cells available for harvest. We perform marrow harvests in an operating room. The donor is put under general anesthesia or, sometimes, spinal anesthesia. We do this so the donor won’t feel anything during the procedure. The surgeon makes small incisions (1/8 inch long) on both sides of the lower back. The surgeon then inserts a needle through these incisions into the pelvic bones, and bone marrow is removed using a syringe to aspirate (suck) it out. For an adult, we typically remove one to one and a half quarts of marrow.

When enough bone marrow has been removed, the incisions are bandaged. No stitches are required. Rarely, donors need to stay in the hospital overnight, but most go home the same day. This depends on how the person feels after having anesthesia.

Sometimes a donor needs blood transfusions during the harvest to replace the blood being collected. Donors most often give one to two units of their own blood two to four weeks prior to harvest. Then we transfuse their own blood back to them during the harvest procedure.

Donors should arrange for someone else to drive them home from the hospital. The bandage on the lower back must stay in place for at least twenty-four hours after the surgery. After that it’s okay to remove the bandage and take a shower. Small strips of adhesive may be on the incision sites; they will fall off over the next week.

After the surgery, the area around the aspiration site may be sore for several days. Mild pain relievers such as acetaminophen (Tylenol) or ibuprofen are usually enough to relieve the discomfort. A fever of up to 101°F for twenty-four hours after having anesthesia is common. If fever persists beyond a day and there are also other symptoms, the donor should call a doctor. Symptoms of infection include extreme tenderness, redness, swelling, and drainage. Infections or other complications are very rare.

Donors should take it easy for a day or two after the harvest surgery. It is normal to feel very tired after anesthesia and bone marrow donation. Most donors feel back to normal after one to two weeks.

Collecting Peripheral Blood Stem Cells
It is possible to collect, or harvest, stem cells from the bloodstream rather than the bone marrow. Donating stem cells in this way is similar to donating blood, but takes a lot longer.

Before we can collect stem cells from the bloodstream, we have to "mobilize," or push the stem cells out of the bone marrow and into the circulating (peripheral) blood. We do this in one of two ways. We use growth factor mobilization or growth factor medicine with chemotherapy. We use this second method only with a BMT patient who is also the stem cell donor (getting an autologous transplant). The collection process is sometimes called leukapheresis, which means "taking away white blood cells."

Growth factor mobilization
To mobilize the stem cells, we give the donor a medicine called growth factor or colony-stimulating factor. Growth factors are human proteins that the body normally produces to stimulate blood cell production and growth. Growth factors can increase the number of stem cells in the bloodstream. We give the donor the growth factor drug as an injection under the skin with a very small needle. The donor must get the drug each day for six to seven days. Some donors feel a little pain at the injection site. Side effects are usually mild and may include general aches and bone pain, flu-like symptoms, and low-grade fever. The bony aches may increase after each day’s injection.

Growth factor medication with chemotherapy
For some patients (not normal donors) receiving autologous transplants (of their own stem cells), we combine growth factor medicine with "priming" chemotherapy. We usually give the chemotherapy for two to three days. Then we inject the growth factors to accelerate white blood cell recovery from chemotherapy. This also mobilizes stem cells into the blood for collection. Ten to fourteen days after chemotherapy, the white blood cell count recovers and the number of stem cells in the blood is much higher than normal. At this point we collect the stem cells.

We reevaluate some patients after their autologous stem cell collection to see how they responded to the priming therapy. This reevaluation (restaging) can include CT scans, X-rays, blood tests, and a bone marrow biopsy.

Apheresis collection of peripheral blood stem cells (PBSC)
We collect the stem cells in an outpatient procedure called leukapheresis, or apheresis. We use a blood cell separation machine to remove some of the stem cells from the bloodstream. We hook up the apheresis machine to the donor’s veins -- one in each arm. Or sometimes we may place a temporary catheter in a neck vein.

Blood is drawn from one lumen or intravenous (IV) line and circulates through the blood cell separation machine. As blood goes through the machine, the machine removes the white cell portion, which is now enriched with stem cells. The blood continues through the machine, and red cells are returned to the donor through the other IV or catheter lumen. 

This procedure may temporarily lower the donor’s blood calcium level, which may cause a tingling sensation around the mouth or in the hands and feet. To relieve these symptoms, the donor may take antacid tablets that are high in calcium, or calcium may be infused. The collection process can also lower the donor’s platelet count. If this happens, he or she will be watched closely for signs of bleeding.

Each collection will last four to five hours. We may need to do several collections depending on the number of cells needed. The hospital will provide snacks during each collection, or donors can bring their own food. Reading, watching television or movies, resting, and talking with visitors can help pass the time.

After we collect the stem cells, we send the collection bag to a processing laboratory, where the cells are counted and processed. If the transplant is scheduled for a later date, a preservative is added to the stem cells and they are frozen. If the transplant is going to happen right away, the stem cells are brought back to the patient room where a doctor transplants them into the patient.