Beta-thalassemia
might sound like the name of a planet from a science fiction novel,
but the truth is a little uglier. Beta-thalassemia is a sever blood
disorder which causes a life-threatening case of anemia. Anemia can
appear in many forms, but the basics behind the disorder are the lack
of the ability of the blood to sufficiently oxygenate the body. This
can be from a simple lack of red blood cells to deformities in the
hemoglobin molecules in the blood stream, among other things.
Beta-thalassemia
is a genetically inherited blood disorder and so the promise of the
emerging field of gene therapy looks at least optimistic for treating
such diseases. So far there has been one case of beta-thalassemia
world-wide which has shown to have been possibly cured through gene
therapy. The French boy, whose name was not immediately available,
was diagnosed with beta-thalassemia at age three and had lived with
the disease for fifteen years. The unlikely savior in this case was a
genetically modified strain of human immunodeficiency virus (HIV) --
the same dreaded virus that causes autoimmune deficiency syndrome
(AIDS).
One
of the most common ways to treat anemia disorders is by way of weekly
blood transfusions. This comes with its own complications though, as
a process known as chelation is often then required to remove excess
iron from the blood before it damages delicate organs.
The
treatment, pioneered by Dr. Philippe Leboulch and colleagues from the
University of Paris, instead uses a genetically
modified version of HIV to supplant the body’s defective
blood-production stem cells with healthy cells. This is no simple
process: first they harvested the same stem cells from the patient’s
own bone marrow. Then they treated the extracted cells with the
modified HIV virus which inserted an undamaged copy of the previously
defective chromosome 11 gene, effectively replacing the damaged
version. Next, the patient underwent chemotherapy to destroy the
remaining stem cells in his bone marrow. And finally, the new stem
cells were injected, completely replacing the previously
malfunctioning cells.
Though
the process has only been completed on one patient to date, it was a
resounding success. Nearly two years later, the patient has been able
to cease taking transfusions and get on with a relatively normal
life.
This
is not the first case of a modified HIV strain used to treat a
genetic illness. Other French researchers had used an engineered
version to cure two children with adrenoleukodystrophy, a very rare
genetic disorder that eventually kills its bearer by slow destruction
of the brain’s myelin sheath, eventually causing nerve impulses to
be unable to be transmitted or received from the nervous system and
the failure of the adrenal glands.
Gene
therapy is only just beginning to get its grip on medicine. Many
other cases of marked improvement due to these therapies can be found
in medical journals and in various places on the internet. Using HIV
is not a common practice yet, possibly due to the stigma of its
deadly AIDS-causing strains. And there may still be some apprehension
over continuing to modify the virus for therapeutic uses in that it
may be possible to create a super HIV which could be even more
prolific than current versions.
However,
to see that medicine is now using virus engineering on what once was
simply a perceived death sentence to cure other life-threatening
diseases and disorders seems to show a large commitment and great
progress by medical science.