|
 |
|
 |
 |
 |
Bone Marrow Transplants In India
|
|
Major hospitals in India have oncology units
comprising surgical oncology, medical and radiation therapy as well
as the crucial Bone Marrow Transplantation (BMT). The BMT unit with
high pressure hipa filters has helped achieve a very high success
rate in the various types of transplantation.
Beginning in early 1983, bone marrow transplantation (BMT) facilities
in India have undergone slow but steady growth. With about 50%
disease-free survival in acute myeloid leukaemia and aplastic
anaemia and 90% survival in thalassemia major, the results are
encouraging. However, the outcome in chronic myeloid leukemia so far
has been poor.
Cord Blood Transplant and Mismatched Allogeneic Stem Cell
Transplant have been performed successfully in India, a feat that is
remarkable and significant, considering the fact that the treatment
costs one-tenth of what it does in the west. Special surgeons are
available for individual organs. Plastic surgeons of repute provide
treatment for head and neck cancer, breast cancer and other
malignancies. Facilities offered include tele-therapy which includes
simulation work stations to ensure high precision and safety during
treatment at the 18 MV linear accelerator or telecobalt machines,
brachy therapy and 3-D planning systems. In orthopedics, the
Ilizarov technique is practiced for the treatment of limb
deformities, limb shortening and disfiguration.
TYPES of Bone Marrow Transplants;
Autologous and Allogeneic Transplants
Two important requirements for a
bone marrow transplant are the donor and the recipient. Sometimes,
the donor and the recipient may be the same person. This type of
transplant is called an autologous transplant. It is typically used
in cases in which a person's bone marrow is generally healthy but
will be destroyed due to medical treatment for diseases such as
breast cancer and Hodgkin's disease. Most bone marrow transplants
are autologous. If a person's bone marrow is unsuitable for an
autologous transplant, the bone marrow must be derived from another
person in an allogeneic transplant.
Allogeneic transplants are more complicated because of proteins
called human lymphocyte antigens (HLA) that are on the surface of
bone marrow cells. If the donor and the recipient have very
dissimilar antigens, the recipient's immune system regards the
donor's bone marrow cells as invaders and launches a destructive
attack against them. Such an attack negates any benefits offered by
the transplant.
What is HLA MATCHING?
There are only five major HLA
classes or types-designated HLA-A,-B, -C,-D, and class III-but much
variation within the groupings. For example, HLA-A from one
individual may be similar to, but not the same as, HLA-A in another
individual; such a situation can render a transplant from one to the
other impossible.
HLA matching is more likely if the donor and recipient are related,
particularly if they are siblings; however, an unrelated donor may
be a potential match. Only in rare cases is matching HLA types
between two people not an issue: if the recipient has an identical
twin. Identical twins carry the same genes; therefore, the same
antigens. A bone marrow transplant between identical twins is called
a syngeneic transplant.
NEW ADVANCEMENTS in Bone Marrow Transplantation
Haploidentical Allogeneic BMT
for patients without donors
Haploidentical Allogeneic peripheral blood stem cell transplant
offers an innovative option for patients who cannot be suitably
matched with a family member, or who do not have an unrelated donor
readily available for transplant.
This technique makes it possible to use partially matched family
members as donors.
In this new procedure, peripheral blood stem cells are collected
from the donor, and depleted of T cell lymphocytes known to cause
graft-versus-host disease. The first treatment phase for the patient
includes chemotherapy, immunosuppressive drugs, and radiation.
Transplant specialists can then infuse the prepared cells from the
donor into the patient's body. This transplant method allows
physicians to select a partially matched donor from the patient's
family whose white blood cells will act as natural killer cells
against the leukemic cells of the patient.
Peripheral blood stem cell
transplants
A relatively recent development in stem cell transplantation is the
use of peripheral blood cells instead of stem cells from bone
marrow. Peripheral blood stem cells (PBSCs) are obtained from
circulating blood rather than from bone marrow, but the amount of
stem cells found in the peripheral blood is much smaller than the
amount of stem cells found in the bone marrow. Peripheral blood stem
cells can be used in either autologous or allogeneic transplants.
The majority of PBSC transplants are autologous. However, recent
clinical studies indicate that PBSCs are being used more frequently
than bone marrow for allogeneic bone marrow transplantation.
The advantages of PBSC transplants when compared to bone marrow
transplants are: in allogeneic transplantation, haematopoietic and
immune recovery are faster with PBSCs which reduces the potential
for disease recurrence, primarily graft-versus-host-disease. In
autologous transplantation, the use of PBSCs can result in faster
blood count recoveries. Also, some medical conditions exist in which
the recipient cannot accept bone marrow stem cell transplants, but
can accept PBSC transplants. Some possible disadvantages to PBSC
transplant versus bone marrow transplantation are: so much more
fluid volume is necessary to collect enough PBSCs that, at the time
of infusing the new stem cells into the recipient, the fluid can
collect in the lungs or cause temporary kidney problems. Also, the
time commitment for the donor for a PBSC transplant is considerable.
When the PBSCs are being collected, several outpatient sessions are
needed and each session lasts approximately two-four hours.
|
|
An easy guide to some of the scientific
terminology.
Allogeneic transplant
When stem cells are donated from one person and transplanted into
another person to be used as a treatment for certain illnesses and
conditions
Autologous transplant
When stem cells are taken from a person and then transplanted into the
same person to be used as a treatment for certain illnesses and
conditions
Cell expansion technology
This allows doctors to increase the number of stem cells in a unit in
a controllable way. Many future treatments rely on cell expansion
technology as these treatments need a larger supply of stem cells
than can be obtained from a single cord blood unit. Cell expansion
technology research is progressing well and the first patented
processes are expected to be in place by 2010.
Haematopoeitic
This relates to the creation of blood in the body. A
haematopoietic stem cell is one that can divide and produce blood
cells.
Human Leukocyte Antigen (HLA)
Tests performed on the cord blood stem cell unit that identifies
tissue types. Tissue types are similar to blood types. For a person
to receive a transplant of cells or tissue from someone else, they
must have the closest possible tissue type 'match'. Our tissue type
is determined by our DNA. There are millions of possible tissue
types, so a large bank of stem cells increases the chance of finding
a matched unit when one is needed
Leukaemia
Is a cancer of the blood forming system, the blood forming system is
found in the bone marrow. In leukaemia, some blood cells do not grow
properly, but remain within the bone marrow and continue to
reproduce in an uncontrolled way. These cells fill up the bone
marrow and prevent it from making healthy white blood cells. This
means the body is less able to fight off infections. There are many
different kinds of leukaemia.
Match / Matched
Refers to a tissue typing match, the scientific term for this is
HLA-type match. Tissue types must be matched as closely as possible
between the person donating stem cells and the person receiving them
to reduce the risk of rejection.
Peripheral blood
This is the blood that circulates around the arteries and
veins of the body.
Processing
The way in which the stem cells found in umbilical cord blood are
extracted from the blood, counted, tested and frozen ready for
long-term storage.
Regenerative medicine
This is about treatments in development that, in the future, may be
able to treat diseases and injuries by using stem cells to repair or
regenerate damaged cells and tissues in the body.
Stem cell
A special kind of cell that can divide many times to make exact copies
of itself, or to make specialised cells that do a particular task in
the body for example a blood cell, bone cell or liver cell. Some
people call stem cells ‘master’ cells or ‘blank’ cells because they
can change into so many different types of cell.
Tissue type / typing
Tissue types are similar to blood types. For a person to receive a
transplant of cells or tissue from someone else, they must have the
closest possible tissue type 'match'. Our tissue type is determined
by our DNA. There are millions of possible tissue types, so a large
bank of stem cells increases the chance of finding a close match
when one is needed.
Transplantation
Taking cells, tissues, or organs and placing them into the same person
or a different person to treat disease.
Unit
Stems cells collected from the umbilical cord are properly
described as a ‘cord blood stem cell unit’.
For Detailed Dossier on
Bone Marrow Transplantation, please write to us at
mktg@mediescapes.com |
|