Two patients have been taken off their HIV drugs after
bone-marrow transplants seemed to clear the virus from
their bodies, doctors report.
One of the patients has spent nearly four months
without taking medication with no sign of the virus
returning.
The team at Brigham and Women's Hospital, in the US,
caution that it is far too soon to talk about a cure as the
virus could return at any point.
The findings were presented at the International Aids
Society Conference.
It is difficult to get rid of an HIV infection because it
hides inside human DNA, forming untouchable
"reservoirs" in body.
Anti-retroviral drugs keep the virus in check within the
bloodstream - but when the drugs stop, the virus comes
back.
HIV gone?
The two men, who have not been identified, had lived
with HIV for about 30 years.
They both developed a cancer, lymphoma, which
required a bone-marrow transplant.
Bone marrow is where new blood cells are made and it
is thought to be a major reservoir for HIV.
After the transplant, there was no detectable HIV in the
blood for two years in one patient and four in the other.
The pair came off their anti-retroviral drugs earlier this
year.
One has gone 15 weeks, and the other seven, since
stopping treatment, and no signs of the virus have been
detected so far.
Dr Timothy Henrich told the BBC the results were
exciting. But he added: "We have not demonstrated cure,
we're going to need longer follow-up.
"What we can say is if the virus does stay away for a
year or even two years after we stopped the treatment,
that the chances of the virus rebounding are going to be
extremely low.
"It's much too early at this point to use the C-word
[cure]."
It is thought that the transplanted bone marrow was
initially protected from infection by the course of anti-
retrovirals. Meanwhile the transplant also attacked the
remaining bone marrow, which was harbouring the virus.
However Dr Henrich cautioned that the virus could be
still be hiding inside brain tissue or the gastrointestinal
track.
"If [the] virus does return, it would suggest that these
other sites are an important reservoir of infectious virus
and new approaches to measuring the reservoir at
relevant sites will be needed to guide the development
of HIV curative strategies," he said.
Berlin patient
Timothy Brown, also known as the "Berlin patient" is
thought to be the first person cured of Aids. He had a
bone marrow transplant from a rare donor who was
resistant to HIV.
The two US cases both received bone marrow from
normal donors.
There was also a report of an HIV cure in a baby born in
Mississippi, US. She was treated with anti-retroviral
drugs at birth so it is thought the virus was cleared from
the body before reservoirs were established.
Dr Michael Brady, the medical director of the Terrence
Higgins Trust, said: "It is too early to know whether HIV
has been eradicated from these men's bodies or whether
it might return.
"However, the case suggests that what happened to
Timothy Brown, the Berlin Patient was perhaps not a
one-off.
"A bone marrow transplant is a complex and expensive
procedure, which comes with significant risks.
"For most people with HIV, it would be more dangerous
to undergo a transplant than to continue managing the
virus with daily medication.
"So while this is by no means a workable cure, it does
give researchers another signpost in the direction of
one."
The head of the Foundation for AIDS Research, Kevin
Frost, said: "These findings clearly provide important
new information that might well alter the current
thinking about HIV and gene therapy.
"While stem-cell transplantation is not a viable option
for people with HIV on a broad scale because of its
costs and complexity, these new cases could lead us to
new approaches to treating, and ultimately even
eradicating, HIV."
http://m.bbc.co.uk/news/health-23132561

But they are not yet sure it is a cure.