Most stem cells
are in your
bone marrow. You also have some that circulate from
your marrow into your blood. Bone marrow stem cells turn into
red blood cells,
white blood cells, or
platelets to help your body stay healthy. If your bone
marrow is damaged or destroyed, it can no longer make normal blood cells. In a
stem cell transplant, healthy stem cells are placed in your body through an
IV to help your bone marrow start to work
When the stem cells come from another person, it is called
an allogeneic transplant. The donor may be a relative or a complete stranger.
The important thing is that the donor's immune system markers are closely
matched to yours. This is more likely when the donor is your brother or
How do you know if you are a good candidate for a stem cell transplant?
Your doctor will consider your health and your age.
People who are good candidates usually are younger than 70, do not have other
diseases such as heart disease or diabetes, and have a normal kidney and liver.
Your doctor will also consider how much your disease has grown and how
aggressive your cancer is. People with aggressive cancer that has spread to
many areas of the body are not usually good candidates. Your doctor may also
consider if you have cancer that has come back, such as relapsed
non-Hodgkin's lymphoma or
How are stem cells collected?
It depends on where
the stem cells come from.
For bone marrow transplantation (BMT), a small
amount of the liquid portion of the bone marrow is removed through a needle
inserted into the bone. This is done many times to collect enough stem cells
for the person receiving the donated bone marrow. This is called harvesting the bone marrow. The bone marrow cells are put
into a blood bag. They are often frozen for future use.
For peripheral blood stem cell transplantation (PBSCT), stem cells are taken from blood. The growth factor G-CSF may be used to
stimulate the growth of new stem cells so they spill over into the blood. G-CSF
is a protein that is produced naturally in the body. The blood is removed from
the vein and passed through a machine that takes out the stem cells. The
machine then returns the remaining blood through a needle in the person's arm
or through a
central venous catheter. This way of collecting stem
cells is called
Stem cells may also be taken from umbilical cord blood. This is something that must be arranged with a blood bank before a baby's birth.
Why are chemotherapy and radiation therapy used before a transplant?
Doctors use chemotherapy and radiation to destroy
your bone marrow. This also gets rid of the cancer cells—along with the normal
cells—in your bone marrow and the rest of your body. Later, when you get
healthy stem cells from a donor, those new cells will go to the marrow and be
able to take over the job of making new blood cells.
How are stem cells transplanted?
A central venous
catheter is inserted into your chest. The stem cells travel through the
catheter into your blood, and to your bone marrow, where they will begin to
produce new cells in 1 to 3 weeks. During this time:
You may be in isolation and given antibiotics
to prevent or treat infection. Because the chemotherapy destroys your white
blood cells, your body will not be able to fight infection until it starts
making new white blood cells.
Your blood will be tested often to
check the levels of red blood cells, white blood cells, and platelets in your
You may need to receive several
transfusions of blood cells and platelets until your
body begins to produce its own.
You may need more antibiotics or other medicines if you get an
What To Expect After Treatment
If the donated stem cells came from bone
marrow or umbilical cord blood, it usually takes about 20 days for your bone
marrow to start producing new blood cells. If the donated cells came from
someone's blood, it may not take that long.
spend 4 weeks or longer in the hospital after an allogeneic stem cell
transplant. About 1 out of 4 people need to be readmitted within the first 3
months because of complications.
After you are discharged from
the hospital, you will continue to see your doctor often. Because you received
someone else's bone marrow, you will need treatment with medicines to prevent
immune system from attacking the donor marrow as
though it were a foreign substance. You may also take medicine to help prevent
the donor cells from attacking your body. Most people who do not have an immune
system reaction take these medicines for 2 to 6 months.
complications can occur after a stem cell transplant. They include:
Graft-versus-host disease. The new cells may
destroy other cells in your body. They most commonly attack the skin, liver,
and digestive system. This happens less often when umbilical cord stem cells
are used. Stem cells from umbilical cord blood are usually used to treat
disease in a sibling or child who would otherwise not have a stem cell donor.
There are very few stem cells found in cord blood, so these cells are not
usually used to treat adults.
Graft rejection. Your body may not
accept the new stem cells.
Severe life-threatening infection. When
your immune system has been weakened, even the most minor infection can be
Veno-occlusive disease. This is a serious liver problem caused by
the high dose of chemotherapy or radiation given before a transplant. Symptoms
will usually appear within 3 weeks of your transplant and include swelling and
tenderness of the liver, weight gain,
jaundice, and fluid buildup in the belly.
When stem cells are collected from another person, the
cells are tested to make sure they match your cells.
transplant from an unrelated donor is more likely to cause problems. But improvements in the way the cells are prepared and matched and in the care of
the person after the transplant have helped reduce problems. It can take 4
months or longer to find a match from an unrelated donor.
Why It Is Done
Allogeneic transplants are used to
treat many diseases, including:
juvenile idiopathic arthritis and
lupus that don't improve with the usual treatments.
How Well It Works
The success of a stem cell transplant
depends on your age and general health, the type and stage of disease, and how
well the donor matches. Serious complications can develop after a stem cell
The original disease often comes back, or relapses,
after an allogeneic transplant. If relapse occurs, it can be treated with a
second transplant, chemotherapy, or other treatments.
Early complications usually occur within 5 to 10
days and include:
Bleeding, because of severe reduction in red blood cells,
white blood cells, and platelets.
Recurrence of the disease that the transplant was
used to treat.
Serious, long-term complications include:
Graft failure. The new stem cells do not
work, or they work for a short time and then fail. If this occurs, the
likelihood of a cure is low.
Graft-versus-host disease (GVHD). The new stem cells attack other cells in your body. If
it happens within 3 months, it is called acute GVHD. If it happens after 3
months, it is called chronic GVHD. After chronic GVHD develops, it may take as
long as 3 years to go away. GVHD affects the skin, gastrointestinal tract, and
liver. It can cause death. GVHD is treated with medicine that lowers the
activity of your
immune system. GVHD does not occur when an identical
twin is the donor.
This is a serious liver problem caused by the high dose of chemotherapy or
radiation given before a transplant. Symptoms include swelling and tenderness
of the liver, weight gain,
jaundice, and fluid buildup in the belly.
What To Think About
Who can donate stem cells?
ages 18 to 60 can donate stem cells. About 17 million people
worldwide are registered to be
stem cell donors. Children may be donors for themselves or a brother or sister.
In some cases, people who are older than 60 can donate.
wish to be a stem cell donor, a blood sample is taken from you and tested for
tissue type. It is then compared with the tissue types
of people needing a transplant. If a match is found, another blood sample will
be drawn to see if your tissue type matches well enough for the
If you are selected as a stem cell donor, you will
have a complete physical exam. You will also be asked questions about your
health and your family history of diseases. You will also be asked to sign a
consent form to have the procedure.
If you are a stem cell donor,
you will receive injections of a drug called filgrastim for several days. (It
is also called G-CSF, for "granulocyte colony-stimulating factor.") Filgrastim
is a drug that helps your body move more white blood cells out of your bone
marrow and into your bloodstream. Blood will be removed from your arm, sent
through a machine to remove the stem cells, and returned to your bloodstream
through your other arm.
The bone marrow collection process is a
surgical procedure done under a
general anesthetic. The procedure takes 1 to 2 hours.
Bone marrow is usually removed from the back of your pelvic bone using sterile
What about umbilical cord blood banking?
cord blood banks have been established in some areas of the United States,
Canada, and many countries in Europe to supply stem cells for related and
unrelated people. Using blood from these banks decreases the time it takes to
search for a match, because the samples are already typed for genetic
information (HLA) and blood group and treated for infection. The match does not
need to be as specific as it does with bone marrow or peripheral stem cells.
Umbilical cord blood transplants also cause fewer problems with
every hospital is able to perform transplants. You may have to travel to a
hospital that has special equipment and specially trained doctors and
How this information was developed to help you make better health decisions.