The case of a middle-aged woman of mixed race, presented at
the Conference on Retroviruses and Opportunisitic Infections in Denver, is also
the first involving umbilical cord blood, a newer approach that may make the
treatment available to more people.
Since receiving the cord blood to treat her acute myeloid
leukaemia - a cancer that starts in blood-forming cells in the bone marrow -
the woman has been in remission and free of the virus for 14 months, without
the need for potent HIV treatments known as antiretroviral therapy.
The two prior cases occurred in males - one white and one
Latino - who had received adult stem cells, which are more frequently used in
bone marrow transplants.
"This is now the third report of a cure in this
setting, and the first in a woman living with HIV," Sharon Lewin,
President-Elect of the International AIDS Society, said in a statement.
The case is part of a larger US-backed study led by Dr.
Yvonne Bryson of the University of California Los Angeles (UCLA), and Dr.
Deborah Persaud of Johns Hopkins University in Baltimore. It aims to follow 25
people with HIV who undergo a transplant with stem cells taken from umbilical
cord blood for the treatment of cancer and other serious conditions.
Patients in the trial first undergo chemotherapy to kill off
the cancerous immune cells. Doctors then transplant stem cells from individuals
with a specific genetic mutation in which they lack receptors used by the virus
to infect cells.
Scientists believe these individuals then develop an immune
system resistant to HIV.
Lewin said bone marrow transplants are not a viable strategy
to cure most people living with HIV. But the report "confirms that a cure
for HIV is possible and further strengthens using gene therapy as a viable
strategy for an HIV cure," she said.
The study suggests that an important element to the success
is the transplantation of HIV-resistant cells. Previously, scientists believed
that a common stem cell transplant side effect called graft-versus-host
disease, in which the donor immune system attacks the recipient's immune
system, played a role in a possible cure.
"Taken together, these three cases of a cure post stem
cell transplant all help in teasing out the various components of the
transplant that were absolutely key to a cure," Lewin said. -Reuters
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