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General
FAQ about Bone Marrow & Peripheral Blood Stem Cell Donation
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What is bone marrow and what does it do?
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What
diseases or disorders can bone marrow transplants or peripheral blood
stem cells help with?
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Why do those with
leukemia, and other patients, need bone marrow transplants or peripheral
blood stem
cells?
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What types
of stem cell transplants are available for those with the above
diseases?
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Is the
actual bone marrow what is
necessary for the patient to recover?
What are hematopoeitic stem cells?
Why does chemotherapy or
radiation therapy kill healthy cells as well as the intended cancerous
cells?
Which is
better for the recipient to receive, bone marrow or peripheral blood
stem cells?
Are
umbilical cord blood stem cells better that bone marrow or peripheral
blood stem cells?
How many patients are in
need of bone marrow transplants (BMT) or peripheral blood stem cells?
How many registered bone
marrow or peripheral blood stem cell donors are there?
What is
Graft Versus Host Disease (GVHD)?
Is it dangerous to donate
your bone marrow or peripheral blood stem cells?
1. What is bone marrow and what does it do?
Bone marrow is the spongy organ found in the core of our
bones. Bone marrow is responsible for manufacturing red
and white blood cells and platelets needed for proper clotting.
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Plasma constitutes about
55% of whole blood. It is the watery, yellowish-clear portion of the blood
which is comprised about 90% water and 10% protein, amino acids, hormones,
and waste to be excreted by the renal system.
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Red blood cells (also
known as erythrocytes, and RBCs) contain hemoglobin (which gives
blood it's red color when rich in oxygen) and are responsible for transporting
oxygen to the tissues. RBCs also help remove CO2, a
byproduct of your body's normal chemical reactions. RBCs have
a life span of about 120 days so obviously it is necessary for the
body to regularly produce more.
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White blood cells (also
known as leukocytes, WBCs) are responsible for fighting off disease,
infection and sickness. Your WBC's are your body's defense
system. There are 5 main types of WBCs. A class called 'granulocytes'
consist of basophils, eosinophils and neutrophils. The remaining two
are lymphocytes and monocytes and help fight infection via the lymph
nodes and spleen. That may seem like a lot of WBCs but in actuality,
there are still more RBCs than white. But a healthy body can
produce more WBC's if needed to fight off an infection. This
is usually experienced when your lymph nodes swell and become
tender. It is a normal reaction when your body is fighting off
an infection. The life span of white blood cells range from a
few days to a few months depending upon the type.
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Platelets (also known as
thrombocytes) are responsible for hemostasis, otherwise known as
clotting, or coagulation. The lifespan of a platelet is about
10 days. Although more complicated than outlined below, in
short your platelets arrive at an injury first and begin plugging
the hole in a blood vessel to prohibit blood loss. Then the
clotting factors in your plasma make the clot more stable by
producing strands of fibrin. This reaction is triggered by the
platelets reaction upon being exposed to the surrounding collagen
fibers. When your platelets react this way, it triggers a
chain reaction in your other platelets and WBCs in the vicinity of
the wound. If you didn't have platelets and clotting factors,
every time you cut yourself you would bleed to death because it
would not stop until there was no pressure to pump the blood out
anymore.
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2. What diseases or disorders
can bone marrow transplants (BMT) or peripheral
blood stem cell transplants (PBSCT) help with?
Diseases which may benefit from stem cell transplantation obtained
by bone marrow or peripheral blood stem cell donors include:
The most comon types of
cancer treated from bone marrow or peripheral blood stem cell transplants
are leukemia, lymphoma, multiple myeloma, and neuroblastoma.
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3. Why
do those with leukemia, and other patients, need bone marrow transplants
or peripheral blood stem cells?
Patients who have
any of the above and other disorders may have diseased or damaged bone marrow and
may not be able to produce sufficient amounts of healthy blood cells,
including WBCs.
As the patient undergoes treatment, the WBC count declines further resulting in a disorder called neutropenia.
Medications such as filgrastim (Neupogen®), which is a growth factor, can stimulate the body to produce more WBCs.
Some patients will undergo filgrastim therapy
before a transplant to increase the WBC output which helps the
patient fight off infection which may prove deadly with a suppressed immune
system. Not all patients with leukemia will be administered
filgrastim. However, those with acute myelcytic leukemia often
receive this drug. It is, however, often used after a bone
marrow or peripheral blood stem cell transplant to help reduce the
chance of infection and fever. It also triggers the production of
stem cells, or non-progenitor cells, which are removed from the patient
before chemotherapy, and re-introduced via IV after the diseased cells
are thought to be eradicated. These cells later turn into healthy
cells which seed the bone marrow and produce vital blood cells.
Radiation
and chemotherapy further damage the bone marrow, making it even more difficult
for a patient to fight off even the common cold. Bone
marrow and stem cells can only be transplanted after the patient's own tissues have
been eradicated with chemotherapy or radiation treatments.
If all
goes well, the healthy new cells will then increase in number and
become that patients new immune system. In essence, transplants
allow the patient to eventually produce healthy cells and platelets.
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4. What types
of stem cell transplants are available for those with the above
diseases?
There are three types of transplant options available to those who
have received chemotherapy or radiation therapy:
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Allogenic
- cells from a patient's parent, sibling or an unrelated
donor. The cells can be removed via surgical bone marrow
harvesting or peripheral blood stem cells harvesting via apheresis.
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Autologous
transplants - stem cells from the patient which have been banked prior to
the onslaught of disease or stimulated to grow via filgrastim therapy
and removed before chemotherapy, or during a remission, can also be
used. Cord blood is also a source of autologous stem
cells. Cord blood is kept (banked) and stored
cryogenically. Using autologous banked cord blood stem cells is rare as most patients do not have their
stem cells banked at birth. Harvested adult, autologous stem
cells are is an option if the patient is able to produce enough stem
cells for re-introduction. For treatment to be effective, the diseased cells
are
removed from the marrow via chemo or radiation and the banked cord
blood stem cells or adult-harvested stem cells can be injected into the patient's
blood. *Autologous transplants are not possible in those who
produce abnormal stem cells, such as aplastic anaemia.
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Syngeneic
transplants - cells from the patient's identical twin. Obviously
only available to those who have twins. The cells can be
removed via surgical bone marrow harvesting or peripheral blood stem
cells harvesting via apheresis.
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5. Is the actual bone marrow what is necessary for the patient to
recover?
Well, yes and no. The patient actually needs the stem cells
derived from the donor's, or his or her own, bone marrow to
eventually seed the bones and grow into healthy marrow so it can produce
healthy blood cells. In allogenic and syngeneic transplants, this marrow is essentially the donor's but becomes
the patient's. In order to survive, we need our own bone marrow to
produce blood cells and platelets. Since the patient's bone marrow's
ability to produce cells has been destroyed by disease and treatment, the donor's bone marrow
will eventually make it possible for patient to produce their own blood
cells.
You cannot live without healthy bone marrow for very long at all.
Transfusions are often necessary during treatment since the patient
cannot produce enough of these blood cells.
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6. What are
hematopoetic cells?
Hematopoetic cells are the cells needed to produce blood
cells. They are stem cells which will grow into blood cells such
as WBC, RBC and platelets.
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7. Why does chemotherapy or radiation therapy kill healthy cells as well
as the intended cancerous cells?
Cancerous cells divide very rapidly, far more rapidly than healthy,
disease-free cells. Chemotherapy and radiation therapy is used to
kill these rapidly dividing cells. But, unfortunately bone marrow
cells also divide very rapidly and are inadvertently destroyed along
with the cancer cells. This is why a transplant is necessary after
radiation or chemotherapy therapy. The new stem cells are needed
to replace the ones which are now gone. Without bone marrow, your
body cannot produce blood cells. You would eventually die of infection,
not be able to give your body the oxygen it needs as well as remove the
waste created by your body's cells and also would bleed out because you
would not be able to clot.
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8.
Which
is better for the recipient to
have, a bone marrow transplant (BMT) or peripheral blood
stem cell transplant (PBSCT)?
While either can be very beneficial to the
patient and highly increase their chances of a full recovery, they are
one and the same. When the bone marrow is collected from an
allogeneic source, it is filtered to remove participles of bone and
fat. RBC's may also be removed if the blood type of the donor is
different from the patient. It
is the stem cells contained within the serum extracted that is injected
into the bloodstream of the recipient patient, and is what makes it possible
for patients to grow new, disease-free marrow. In either BMT or
PBSCT, the donor is put on filgrastim therapy to increase the amount of
stem cells. Hematopoietic stem cells are
the cells needed for life, that will seed themselves into the marrow to
begin producing their own blood cells. Unfortunately, there
are more stem cells found in the bone marrow than in the blood, even
with filgrastim therapy. So, obtaining enough stem cells this way
can be difficult.
Whether or
not one is better than the other depends upon the study. However,
according to one finding ["Hematopoietic stem cell
transplantation for treatment of acute leukemia" Harada, M. -
Department of Internal Medicine II, Okayama University Medical School,
Japan] autologous PBSCT is increasingly being preferred over
autologous BMT, as well as allogeneic PBSCT over allogeneic BMT.
The conclusion is that over all, PBSCT is becoming the treatment option
of choice with those who qualify. This
is good news since PBSCT is easier on the donor than BMT as it is non
surgical and has no true downtime other than slight bone discomfort due
to filgrastim therapy.
According
to others, however, BMT still remains in favor.
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9. Are
umbilical cord blood stem cells better that bone marrow or peripheral
blood stem cells?
Cord blood stem cells contain hematopoietic cells and cells which can pretty
much develop into any tissue type. According to the Genetic
Science Leaning Center - University of Utah, cord blood stem cells are
less likely to be rejected by the body. They also
advise that since the cord blood does not have mature immune cells, they
are less likely to attack the patient, triggering what is known as
Graft-versus-Host Disease, or GVHD.
Nonetheless,
cord blood is often in short supply as most people do not think to, or
are not willing to, donate their baby's cord blood after birth.
Many times, the umbilical cord is simply wasted and thrown away.
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10. How
many patients are in need of bone marrow transplants (BMT) or
peripheral blood stem cells?
It is estimated that 35,000 children and adults in
the United States are diagnosed every year with a condition which could
be treated with a bone marrow transplant. The more donors that sign up, the better the chances of a recipient finding his or her lifesaving
match. Possibly you!
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11. How
many registered bone marrow or peripheral blood stem cell donors are
there?
At the time of this writing, the National Marrow Donor
Program (NMDP) boasts a registry of over 5.5 million donors.
While you may feel that certainly sounds like a lot, the chances of
finding a match have been reported as much as 1:20,000 and as little as 1:100,000; the ratio is even
higher for minority groups. This ratio significantly lowers the
chances of funding a life saving match. All the more reason to become
a donor.
As of November
2005, the World Marrow Donors Association boasted 10 million registered bone
marrow or blood stem cell donors in the whole world. Incredible!!!
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12. What
is Graft Versus Host Disease (GVHD)?
Graft-versus-Host Disease, or GVHD, is a disorder triggered by an
immune response of the donor's stem cells in the recipient's body.
The Graft is the stem cell and the host is the recipient. The
donor's stem cells recognize the recipient's tissues as a foreign body
and begin to attack it. It is essentially a secondary disease as
it is a disorder on top of the already present disease, such as
leukemia. The incidence is increased when there is a non-perfect
match, or a less than 6 out of 6 HLA (human leukocyte antigen) match,
although it can happen at any time.
GVHD occurs
less in cord blood stem cell transplants. It has even been shown
to occur less in allogeneic BMTs if the stem cells are cryopreserved
first. A patient
can be conditioned with immunosuppressants such as tacrolimus (FK-506)
and cyclosporine,
antimetabolites (methotrexate) and/or with steroids to help lower the
chances of GVHD.
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13. Is it dangerous to donate
your bone marrow or peripheral blood stem cells?
While there are inherent risks to any surgical procedure, the risks
are nominal compared to the benefits they will bring. However, you
must know the risks before you are informed.
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Filgrastim
and Pegfilgrastim Use: The risks, complications or side effects
related to filgrastim therapy proceeding the donation of either BM
or PBSC are as follows: bone pain (common), headache, a feeling of
pressure in the bones, inability
to get comfortable, swelling or redness at the injection site,
nausea. **Contact
your doctor if you should experience chills, congestion, diarrhea,
or rash. If you should experience shortness of breath,
wheezing, sweating, increase in blood pressure or heart rate,
swelling of the ice, mucous membranes and a tightness in the throat
and chest, excessive pain, fever (over 100.5º F) seek medical
attention immediately and also contact your doctor to let them
know. Also let your doctor know if you experience pain or swelling around a wound
or wound healing problems. If you notice any swelling or painful
areas in the upper left area of your abdomen you must call your
doctor immediately. Spleen enlargement and rupture have occurred
in some patients, although it is rare, in those who take filgrastim
or pegfilgrastim. Do not take filgrastim or pegfilgrastim if
you are pregnant or nursing as its effects have not been studied in
this regard. Read more about a common pegfilgrastim product
used, Neulasta.
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Bone Marrow Aspiration:
Risks associated with anesthesia such as allergic reaction, asthma
attacks in those susceptible and who under go General anesthesia,
and other medication allergies. Infection resulting in
skin necrosis, substantial scarring, keloids in those who are prone
are also risks of bone marrow donation.
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