Posted on 02/14/2008 10:07:27 PM PST by neverdem
Even the best drugs currently available cannot weed out HIV from all of its hiding places within the body, according to a new study of HIV patients in the United States. The discovery seems to confirm doctors' suspicions that once the virus gains a foothold, it can never be fully eradicated from the body.
After years of aggressive drug treatment, the virus still hides out in significant reservoirs, particularly in tissues surrounding the gut lining, the researchers report. Cells in these tissues, a part of the immune system called 'gut-associated lymphoid tissue', remain infected with the virus even though the patient may be leading an apparently healthy life.
Many HIV patients can manage their infection with a cocktail of drugs called antiretroviral therapies (ARTs). These can reduce their 'viral load' — the amount of virus circulating in the blood plasma — to undetectable levels.
But the new study shows that even in such 'non-infectious' patients the virus is still lurking in gut tissues, and still infecting other immune cells in the blood.
"It might not ever be possible to completely eradicate the virus from the body, even though people are doing well," says Anthony Fauci, director of the US National Institute of Allergy and Infectious Diseases in Bethesda, Maryland, who led the research. He adds, however, that this doesn't mean that patients will be more likely than previously thought to pass on the virus to others.
Incurable
The finding underlines HIV's status as an 'incurable' infection, although in many cases doctors are able to stave off the onset of full-blown AIDS by giving patients sustained courses of drugs.
Indeed, so effective are current drugs that most say HIV should now be seen as a chronic disease requiring lifelong management, in the same way as diabetes or chronic hypertension. "It's not a death sentence," says Deenan Pillay of University College London, an expert on antiviral treatments.
Earlier this month, the Swiss National AIDS Commission broke with convention by declaring that HIV-positive patients who had had successful antiretroviral treatment could be declared 'non-infectious' through sex. Other health agencies still maintain that the only safe way to prevent HIV transmission is to practice safe sex, particularly by using a condom.
The new results show that even state-of-the-art drugs cannot stop HIV replicating in certain body tissues, Pillay says. "We have always known that current paradigms of treatment are not sufficient. If anything, this demonstrates that there's even further to go."
Fauci and his colleagues studied eight HIV patients, who had been taking ART drugs for several years, and in one case nearly a decade. All were in good health with low blood plasma levels of the virus. But when the researchers took biopsies of their gut lymphoid tissue, they found that HIV was still present, and levels of CD4+ cells — the cells targeted by the virus — were lower than normal.
The researchers also compared DNA from HIV found in the gut with DNA from HIV found in white blood cells , and found that they were very similar, indicating that the two tissues constantly re-infect one another as the virus replicates; the gut reservoir is not isolated from the rest of the body. The results are published in the Journal of Infectious Diseases.
Stamped down early
Pillay argues that HIV tests should be given to more patients who show the flu-like symptoms of early infection, in a bid to identify more people who have only just been exposed to the virus. Because the virus colonizes the gut tissues early in infection, rapid intervention may help to reduce the size of this viral reservoir. That could in turn make it easier to keep blood plasma viral loads low during the course of the disease.
Last year, Britain's chief medical officer Liam Donaldson wrote to doctors, urging them to test more widely for the virus. "There's a push to get wider testing, and I'm personally very much in favour of it," Pillay says.
Reducing viral reservoirs by early intervention could particularly help patients without access to top-of-the-range drug treatments, Pillay suggests.
I wouldn’t really want a woman like that, anyway.
I’ll be checking pupils as clarification.
I don’t see as a way to hold back any potential pleasure I might have.
I’m 22 and I haven’t even kissed a girl yet. Mostly because nobody would want to kiss me, but that’s another story. (I like Rodney Dangerfield)
I do like to have a few drinks every once in a while, so I hope that I won’t go passed the point of no return, and drop my pants for anybody. I wouldn’t be able to forgive myself.
It’s also something my friends would cheer me for.
Polio and smallpox have been reduced to virtually non-existent threats to public health. Hepatitis B, Chickenpox and shingles (same virus) all have effective vaccines.
Once you get Polio, what is the cure? Prevention is one thing, but for all the focus on cures, there really isn’t much hope.
Only a small number of polio cases progress to permanent paralysis. Most of them “cure” themselves.
In other words if something has never been done, it’s a waste of money to try. Scientists and engineers have forever had to fight that attitude.
***I didn’t say that. Note that you said it, as a straw argument so that you could argue against it. I am an engineer so I’m fully aware of the attitude you point out, but you have misidentified it as belonging to me because you chose the path of straw argumentation. AIDS is a disease that gets about 10X the research resources compared to the number of deaths when you compare it to things like heart disease, diabetes, toenail fungus, whatever. It’s a rathole.
And no virus ever will be cured if the research doesn’t find a technique.
***I’m all for it, right after we solve a bunch of other problems that kill more people than AIDS does. AIDS is a fully preventable disease for >95% of its recipients.
A breakthrough on one virus will open the door to the means of attacking them all.
***And a breakthrough on diabetes or some other disease could help open the door to knocking down viruses. So long as we’re pouring money down ratholes, it should be proprotional money down proportional ratholes that are responsible for a proportional amount of deaths.
It’s not just a matter of AIDS and homosexuals. It just happens that circumstances have conspired to make them into politically correct human guinea pigs.
***Well, that part I agree with. If the patient is gonna die anyways, might as well use experimental treatments in the hopes that something will be learned.
So, for the ones that don’t “cure themselves”, there is no cure, right?
Is there a cure for any virus? There are treatments for viruses, but it still sounds like there’s no cures. And since there’s a vaccine for Polio, that would point to the right direction for research for viruses — prevention rather than cure.
Nanotech will redefine what can and can’t be done. And there won’t be many “can’ts” left.
"There are antiviral drugs that accelerate recovery from viral illnesses. For example, the following agents could be considered for treatment of specific viruses: ganciclovir for cytomegalovirus, acyclovir for varicella-zoster virus or herpes simplex virus, amantidine or rimantidine for influenza A, neuraminidase inhibitors for influenza A or B, pleconaril for enteroviruses, and ribavirin systemically for parainfluenza and respiratory syncytial viruses."
I'm not sure what your definition of "cure" is but if it's complete recovery without disability and no need for ongoing treatment, several of these meet that criteria.
Yup, you never know when their number is up, for one thing.
Sounds good enough to me.
Of course, I still think pouring down money on an AIDS cure is a rathole, and the money rathole should be proportionate to number of fatalities for each disease. But it’s nice to see that a supposed cure for at least one virus has been found.
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