A new study suggests that the replication of HIV may slow or stop altogether
in patients who are on long-term treatment, although remnants can still lurk in
And the researchers now suspect that the virus is especially weak in those
people who started treatment immediately after becoming infected.
The study is very small, involving just eight patients. However, the
findings add more evidence to the debate over how soon patients should begin
drug treatment after they're diagnosed as being infected with HIV. One of the
study authors is ready to say that treatment must begin immediately.
"Patients should be started on therapy as soon as they are diagnosed to
prevent the virus from hiding in large numbers of cells," said the
researcher, Sarah Palmer, deputy director of the Centre for Virus Research at
Westmead Millennium Institute for Medical Research, in Australia. "Diagnosing
HIV infection early and initiating therapy immediately is crucial for limiting
the number of cells containing HIV."
A possible weakness
While doctors can use drugs to kill the Aids virus in the body, it's
impossible to eliminate it completely. That means there's no cure for HIV infection
or Aids, the potentially deadly condition that the virus causes.
But what does the virus do when a patient is on medication – does it keep
replicating [making copies of itself] or does it hide? The authors of the new
study sought to find an answer by analysing immune-system cells taken from
eight HIV-infected patients. All had been taking anti-HIV drug treatment for
This combined drug treatment is known as antiretroviral therapy (ART).
The researchers analysed the cells and found that drug treatment appeared to
stop the virus from replicating an important finding that suggests a
possible weakness. However, HIV didn't vanish but instead hid in certain types
of immune-system cells known as "resting memory T cells". These cells
"remember" how to fight a particular body invader, such as a germ or
virus and sit around waiting for it to return.
"These cells can remain dormant for many years even though they are
carrying HIV," Palmer said. "When these cells start to replicate or
are stimulated to replicate as part of our normal immune response, they also
produce HIV, keeping the virus viable. Essentially, these cells are a ticking
time bomb in patients, and once they are ignited they explosively produce
Immediate therapy crucial
This finding confirms previous research showing that the lurking virus is
"very stable for years," said David Schaffer, director of the
Berkeley Stem Cell Centre at the University of California, Berkeley. "It
means that treatments must be developed to directly eliminate this long-lived
pool, which is challenging," said Schaffer, who is familiar with the
However, there's some good news. The numbers of these cells were smaller in
patients who had started treatment soon after being diagnosed instead of
waiting until they began to show symptoms.
"Diagnosing HIV infection early and initiating therapy immediately is
crucial for limiting the number of cells containing HIV," Palmer said.
"The scientific community must develop better strategies to flush HIV from
its hiding place in patients without causing new infections."
Schaffer agreed. A treatment can't just halt the virus from growing in the
body and wait for the infected cells the "latent pool" to die out, he
said. "Finding a cure for HIV means that therapies must be developed to
directly eliminate the latent pool of virus."
The study will appear online in the Proceedings of
the National Academy of Sciences.
For more about HIV/Aids, try the US National Library of Medicine.