Early days of course, but a known
drug has proven it can flush out or identify infected cells and plausibly allow
them to be destroyed. That has never
been possible before. It may still be
quite impossible to achieve one hundred percent effectiveness but anything that
can also lead to a continuing reduction in the medication load is hugely
important.
I suspect though that below a
rather low level that the active immune system will turn out able to keep the
disease fully suppressed, but that remains to be seen of course. This disease has disappointed so many ways
that we all must be conservative. Success
has been in small bites.
Meanwhile this is also hopeful
and joins the present drive toward an outright cure which is now seen on the
horizon. We are getting there.
AIDS cure breakthrough? Scientists say they've used a cancer drug to
flush out the virus
Some 34 million people around the world are living with HIV, which
destroys the immune system and has caused about 30 million AIDS-related deaths
since the disease first emerged in the early 1980s.
FRIDAY, JULY 27, 2012, 11:56 AM
(PARIS-AFP) - Scientists in the United States said Wednesday they
had used a cancer drug to flush out the AIDS virus lurking dormant in trial
patients' white blood cells -- a tentative step towards a cure.
The ability of the HIV genome, or reproductive code, to hide out in
cells and be revived after decades poses a major obstacle in the quest for a
cure.
Being able to expose the virus in its hiding place would allow
scientists to target the host white blood cells in a killing blitz.
"It is the beginning of work toward a cure for AIDS," David
Margolis, co-author of the study published in the journal Nature, told AFP
as the International AIDS Conference was under way in Washington .
HIV is a retrovirus, inserting its DNA into the genome of host white
blood cells, CD4+T cells in this case, and turning them into virus factories. Sometimes
it goes into hiding in some cells even as others keep on producing.
Some 34 million people around the world are living with HIV, which
destroys the immune system and has caused about 30 million AIDS-related deaths
since the disease first emerged in the early 1980s.
In the latest study, researchers in the United States used the chemotherapy
drug vorinostat to revive and so unmask latent HIV in the CD4+T cells of eight
trial patients.
The patients were also on antiretroviral drugs, which stops HIV from
multiplying but have to be taken for life because they do not kill the virus
hidden away in reservoirs.
"After a single dose of the drug, at least for a moment in time,
(vorinostat) is flushing the virus out of hiding," Margolis said of the
trial results -- the first drug ever shown to do so.
"This is proof of the concept, of the idea that the virus can be
specifically targeted in a patient by a drug, and essentially opens up the way
for this class of drugs to be studied for use in this way."
The drug targets an enzyme that allows the virus to lie latent.
The researchers cautioned that vorinostat may have some toxic effects
and stressed this was merely an early indication of feasibility that had to be
explored further.
Exactly what would happen after the virus was unveiled in reservoir
cells was also not certain, said Margolis.
"We know that many cells that produce HIV die in the process. We
know many cells that produce HIV can be identified and killed by the immune
system. As far as we can tell, all the viruses floating around while patients
are taking therapy don't get into cells because they are blocked by the
therapy," he said.
Without a host cell, the virus would die within a few minutes.
"There is a possibility that this could work. But ... if it is only
99 percent true and one percent of the virus escapes, it won't succeed. That is
why we have to be careful about our work and what we claim about it."
In a comment published with the study, HIV researcher Steven Deeks said
the research provided "the first evidence that ... a cure might one day be
feasible".
But, as is common with early clinical trials, the study raised more
questions than answers -- including ethical concerns about giving potentially
toxic drugs to HIV-infected people who are otherwise healthy, he said.
"These data from the lab of David Margolis are genuinely exciting
for those exploring pathways to achieving a cure for AIDS," Oxford
University HIV researcher John Frater told AFP, calling for investment in
further research.
HIV immunologist Quentin Sattentau called the findings promising, but
said other types of reservoir cells, including in the brain, may not respond to
this treatment.
"Thus there is a long way to go before we will know if this can
work to completely eradicate HIV from an infected person."
mlr/gk
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