Biomedical Engineering Reference
In-Depth Information
These proteins, found on the surface of the most of the cells in the body, are known
as human leukocyte antigens—HLA antigens—giving the body's immune system
the ability to determine what belongs and what does not belong to the body.
Whenever the immune system does not recognize the series of antigens on a cell
surface, it creates antibodies and other substances to destroy the cells with non-
recognizable antigens. These agents are also: infection-causing fungi, bacteria,
viruses, tumor cells, and foreign agents, such as splinters. In this way, the immune
system defends the body against potential invaders that can enter the body and
cause harm. Regarding the bone marrow transplant to work, the recipient's immune
system must not try to destroy the donated marrow. This comprises that the anti-
gens—HLA system on the donated marrow cells have to be identical, or very simi-
lar to the antigens on the cells of the recipient.
In 1973 the first unrelated bone marrow transplantation on a 5-year-old patient
suffering from severe combined immunodeficiency syndrome was performed by a
team of physicians at Memorial Sloan-Kettering Cancer Center in New York City
[
3-
6
]. The donor was found in Denmark through the Blood Bank at Rigshospitalet
in Copenhagen. The patient received multiple infusions of marrow and after the
seventh transplant, engraftment was established and hematological function rapidly
normalized. By this time, physicians had gained enough experience with bone mar-
row transplantation to determine that three types of antigens: HLA-A, HLA-B, and
HLA-DR, were crucial in determining a match between donor and recipient. An
individual inherits one of each of these three antigens from each of his/her parents.
Therefore, a total of six antigens from the donor must match the six antigens of the
recipient. Even with this careful matching, transplant may still fail because the
recipient's immune system destroys the new marrow cells (called graft rejection), or
because cells in the donor's marrow try to destroy the recipient's cells (called graft-
versus-host disease, or GVHD).
In 1990, Dr. E. Donnall Thomas was awarded the Nobel Prize in Medicine for his
pioneering work on transplantation [
7-
11
]. During the early to mid-1970s, Thomas
performed more than 100 transplants for patients with aplastic anemia and leukemia
with HLA-A, HLA-B, and HLA-DR identical siblings. Because of Dr. Thomas's
work and the dedication of many other physicians in the field of unrelated donor
bone marrow transplantation, the procedure has evolved from an investigational
therapy with uncertain benefit to a preferred first treatment for many patients [
1-
9
] .
Transplantation of Cord Blood and Adult Peripheral
Blood Stem Cells
In 1988, successful transplantation occurred in a young boy with Fanconi anemia
using umbilical cord blood collected at the birth of his sibling [
10
] . The patient
remains alive and well to this date. In 1992, a patient was successfully transplanted
with cord blood instead of bone marrow for the treatment of leukemia [
10
] . Over the
