A recent study
compared the outcomes following transplantation of bone marrow stem cells and
peripheral stem cells from unrelated donors.
Bone marrow is the
spongy tissue that is present inside the bones. It is involved with production
of blood cells such as leukocytes (white blood cells), erythrocytes (red blood
cells) and platelets. Leukocytes are responsible for fighting off invading
infection while red blood cells carry oxygen to various organs of the body.
Platelets, on the other hand, prevent excessive bleeding.
Blood and bone marrow
transplant is a highly specialized procedure that is done "when special cells
called the stem cells (found in the bone marrow) are taken out, filtered and
given back to either the same person or the other individual."
transplantation is needed in patients suffering from blood cancers including
There are two types of
bone marrow transplants. They are namely:
bone marrow transplant
- In this transplant, the donor's cells are re-introduced
into the same person.
2. Allogenic bone marrow transplant
- In this transplant, the donor is a person whose 'tissue has the same genetic
type as the person needing the transplant (recipient). Because tissue types are
inherited, similar to hair or eye color, it is more likely that the recipient
will find a suitable donor in a brother or sister. This, however, happens only
25 to 30 percent of the time.'
Claudio Anasetti et al
conducted clinical trial over two
years to compare the chances of survival for patients following transplantation
of peripheral blood stem cells or bone marrow stem cells from non-related
donors. The study was published in the October issue of The New England Journal of Medicine.
Peripheral blood stem
cells are the blood cells that have moved from the bone marrow into the blood
following administration of special drugs like filgrastim or lenograstim, a
process that is identical to routine blood donation 'which collects the
peripheral blood stem cells through a tube inserted in a vein. A critical step
before the transplant involves finding a donor that is tissue matched to the
About fifty transplant
centers of the United States and Canada took part in this trial. The study
recorded data of 273 patients who received peripheral blood stem cells and 278
patients who received bone marrow stem cells.
The study showed no significant variations in the relapse
rates, overall survival or acute graft-versus-host disease (GHVD) between
recipient and unrelated donor. Engraftment was quick in recipients of
peripheral blood stem cells. These patients also reported high rates of chronic
graft-versus-host disease (GHVD).
Anasetti, the lead
author of the study mentioned, "Although peripheral blood stem cells from
related donors have demonstrated clinical benefits, our trial demonstrates that
when these stem cells originate from unrelated donors, they are not superior to
bone marrow stem cells in terms of patient survival, and they increase the risk
for chronic GVHD."
The author further
added, "More effective strategies to prevent GVHD are needed to improve
outcomes for all patients receiving unrelated donor transplants."
The scientists firmly
believed, "There is a need to develop transplantation approaches that decrease
the risk of graft failure when bone marrow is used and that decrease the risks
of acute and extensive chronic GVHD when either stem-cell source is used."
The study was
financially supported by the National Heart, Lung and Blood Institute
(U10HL069294), the National Cancer Institute and the National Marrow Donor
Peripheral-Blood Stem Cells versus Bone Marrow
from Unrelated Donors; Claudio Anasetti et al; N Engl J Med 2012;
367:1487-1496, 2012DOI: 10.1056/NEJMoa1203517