Blood Stem Cell Infusions

What is a blood stem cell?

A blood or bone marrow stem cell is a special type of cell in the body that can develop into many different types of cells, including red cells, white cells and platelets. 

Why do we need blood stem cells?

Patient stem cells grow new cells for the body, and replace cells when existing cells die. They can divide over and over again, and create new blood cells all through our lives. These cells help the body grow, heal and stay healthy. The stem cells come from the bone marrow and then are found in the blood stream.

What conditions are treated with stem cells? 

Most commonly, stem cells obtained from a child’s own body are used to treat lymphoma, neuroblastoma or high-risk brain tumors. Rarely, these stem cells are used with other types of solid tumors as well.

Why do children with cancer need blood stem cells?

Chemotherapy helps kill cancer, but if given in very high doses, it may also wipe out a patient’s stem cells. The bone marrow, where these stem cells are produced, is one of the most sensitive of all organs to chemotherapy. Standard doses of chemotherapy cause blood counts to go down, but don’t harm bone marrow stem cells very much. After standard chemotherapy, the patient’s stem cells help the marrow to recover fully. In certain very serious types of cancer, patients cannot be cured with standard doses of chemotherapy, and very high doses are needed. Before giving high doses of chemotherapy, patients undergo a procedure to collect their cells, which are stored in a freezer for later use.  After high-dose chemotherapy is administered, the stored stem cells can then be given to the patients as an infusion, allowing their bone marrow to recover fully.

If there are leftover stem cells, can they ever be used by a patient? 

Sometimes there are surplus stem cells after care has been completed. For most patients, those surplus cells will not be used. If a patient’s cancer comes back and additional treatment is needed, their blood counts can sometimes become very low as a result of that treatment. In that event, blood stem cells could be given to help their blood counts recover and strengthen their bone marrow, including the use of stored or newly extracted blood stem cells.  

How are bone marrow stem cells collected from blood?

Most often, a patient’s stem cells are collected by a simple process called apheresis. 

First, patients are treated with a drug that helps increase production of stem cells in the blood. The medication also helps speed recovery from adverse side effects if patients are being treated with chemotherapy.

Next, blood is removed from the patient, the stem cells are removed from the blood by a machine, and the blood is then circulated back into the patient. This process is very similar to the routine donation of platelets or plasma.

Children in treatment for cancer often have a central venous catheter, also called a central line. This allows doctors to give them medicine and fluids, and to obtain blood tests without the need for a new needle stick every time. The central line can be used for apheresis as well, reducing discomfort associated with collecting blood stem cells.

If children don’t have a central line, doctors will put in a temporary line before collecting stem cells. This is a minor surgical procedure. Patients are not allowed to eat anything before the procedure, and are sedated while the line is inserted in a vessel in either the neck or leg.

The actual stem cell collection process takes about three hours, and patients usually relax in a bed or chair. They often watch movies, play video games or take naps while it is happening. Patients are usually not sedated during this process—only very small children who cannot be coaxed into relaxing in a bed or chair or their parents’ arms for a few hours receive sedation, which is usually something mild like diphenhydramine (Benadryl). 

If a child’s cancer returns, can a patient’s cells be recollected? 

Yes. If the care during relapse will require the patient’s cells, the cells can be recollected using the same process that would be used for initial care.

Are there any side effects caused by collecting patient stem cells?

• The medication that increases stem cell production (which many patients are already on because of their chemotherapy) can cause aches and pains or other flu-like symptoms. 
• Sometimes when patients have low levels of calcium, apheresis can cause muscle spasms, nausea or fainting. Physicians work to monitor and support calcium levels to be high enough to prevent this. 
• Sedation also can cause children to be groggy or tired; the goal is always to avoid sedation when possible.

How are a patient’s stem cells stored while they are waiting to be transplanted?

Stem cells are frozen in liquid nitrogen tanks, which are known as cryogenic freezers, at temperatures hundreds of degrees below freezing.

How long do stem cells last when they are frozen?

It is likely that patient stem cells can be stored for a few decades and be viable for use.