Signs of infection with Mycobacterium abcessus, which
primarily attacks those with suppressed immune systems
In 2004, medical researchers began noticing cases where patients, primarily middle-aged Asians, sought treatment for frequent opportunistic infections. Developing these infections, which mainly affect people with compromised immune systems, is a key sign of AIDS, and yet these patients test negative for HIV, the AIDS virus.
According to a new study published in the New England Journal of Medicine, an autoimmune response—when your immune system attacks your own body—triggers the immunodeficiency. But we still don’t know why the autoimmune response develops abruptly at around age 50.
Thanks to modern treatments, HIV, though incurable, is far from the death sentence it once was. But it is still a life sentence, coming with the high cost, both personal and economic, of chronic disease, making avoiding infection in the first place a major goal for public health agencies. To that end, after numerous trials, the FDA has now approved Truvada, a combination drug that is already being used to treat HIV, as a preventative.
Last April, we reported on the failure of Truvada, an oral anti-HIV pill, to prevent infection in African women. The results of the trial were disappointing, and surprising, because Truvada had been found to prevent infection in 90% of gay men who took it religiously. We pointed out at the time that the researchers had yet to analyze blood samples they’d taken from the women in the study. Those samples would show whether the women had been taking the drug as prescribed, which would suggest that its failure was due to some biological factor, or whether they had been failing to take the drug.
It looks like it’s the latter. This week, the NYTimes reports, the researchers announced at an AIDS research conference in Seattle that of the women who got infected, only a quarter of them had any Truvada at all in their blood. Read More
Vaccines usually work by getting the body to make antibodies against a virus, so when the virus appears on the scene, the immune system is prepared to tag it for destruction. But getting the body excited about making such antibodies isn’t always easy. It’s this stumbling block that has made HIV vaccines so disappointing so far, and in response, some scientists have reached for the big guns of biology. In a paper published today in Nature, one team reports that they’ve been able to make mice immune to HIV using, of all things, gene therapy.
Best known as a process for replacing faulty genes with fresh ones to treat chronic diseases, gene therapy seems, at first glance, like overkill. It involves engineering a lab-grown virus to permanently insert a gene into a patient’s genome, and it can be dicey, to say the least. Despite two decades of research, no gene therapy treatments have made it out of clinical trials. But given the difficulty of getting the immune system to buckle down and make antibodies against HIV on its own, using gene therapy starts to make a kind of sense. Read More
For African women looking to avoid pregnancy, hormone shots seem like a good choice. They don’t require your partner to take responsibility for birth control, and they can be given once and then forgotten about for months. But that could be shaken by a study of nearly 4,000 women in seven African countries that found that hormone shots double a woman’s risk of contracting HIV, as well as doubling the risk of her passing it on to a partner. And it doesn’t appear to be because of decreased use of condoms in couples where the woman is on the shot: the researchers, who published their work in The Lancet Infectious Diseases, accounted for that, and found that the effects were still there.
Why this happens isn’t clear, but it’s possible that the hormones in the shot may alter the environment of the female reproductive tract to make it a more livable place for HIV. The team found that those on the shot have higher concentrations of the virus in their genital fluid than those not on birth control, though blood levels remain the same, suggesting that there’s something to the idea that the vaginal environment is altered. More work probing this finding will be required, perhaps including a randomized controlled study, which this was not. But going forward, the researchers say, doctors providing birth control shots in clinics in Africa, where the prevalence of HIV is a public health crisis, should emphasize that condoms should be still be used in order to avoid spreading or contracting the virus.
[via the NYTimes]
Image courtesy of a.drian / flickr
What’s the News: After a bone marrow transplant cured a Berlin man of HIV in 2008, scientists have been working to see whether similar, though less drastic, measures could be a treatment for the disease. And judging from the results of a recent clinical trial that used gene therapy to accomplish the goal, there’s potential.
What’s the Context:
What’s the News: Researchers have embarked upon an experiment that, if not for the tragic circumstances of the African AIDS epidemic, might be familiar to many parents: paying kids to follow the rules. South African schoolchildren 13 years and older in the study could earn up to $400 if they manage to stay HIV-free for 24 months. In South Africa, which has the most HIV/AIDS-infected people of any country in the world, more than 17 percent of the population has HIV, with girls at especially high risk.