A paper being published in the peer-reviewed journal Human Gene Therapy by researchers from the Queensland Institute of Medical Research suggests that genetic therapy, targeting one specific protein in HIV, may impede replication of the virus to the extent that HIV-infected humans will never develop AIDS.
The study is focused on a single protein that HIV depends on to make more of itself, called Tat. Researchers have developed a mutant form of Tat, called Nullbasic, that when introduced into an HIV cell by a retrovirus (purpose-built to sneak into viruses and hack their genetic code) prevents HIV from replicating. You can think of it a little bit like a book of instructions that each HIV cell has, telling it how to replicate: the Tat protein makes up three important pages of that book, but the retrovirus can get into the book without HIV noticing and rewrite those three pages with Nullbasic instead, which screws up the replication process. Testing on cultured human cells suggests that this technique works very, very well; here's the really meaty bit from the abstract:
Virus replication in primary CD4+ cells expressing a Nullbasic-ZsGreen1 fusion protein was inhibited by approximately 8 to 10-fold. These experiments demonstrate the potential of Nullbasic, which has unique inhibitory activity, as an antiviral agent against HIV-1 infection.
In other words, the gene therapy that tweaked the existing HIV protein into Nullbasic reduced the ability of HIV itself to spread by a factor of 10, a result that the researchers understatedly describe as "potent."
This therapy would not prevent or cure HIV: users receiving the treatment would still have HIV, but the virus would stay largely dormant, unable to replicate effectively. And this is what would prevent (or "cure") AIDS, which is what can develop when HIV replicates to the extent that the human immune system becomes severely compromised. With the therapy keeping HIV locked down, your immune system would stay healthy and you'd never get AIDS.
Animal trials of the therapy are scheduled to start in the "very near future," and human trials would come after that. In humans, the way the therapy would work is that your own stem cells would be extracted and modified with the Nullbasic HIV resistance therapy. After growing for a bit in a lab, the stem cells get reintroduced into your body, where they'd gradually generate an entire immune system with HIV resistance built-in. The goal is that people with HIV would just need this one therapy one single time, and then they could stop taking anti-retroviral drugs and essentially have the same quality of life that they'd have if they weren't infected with HIV at all.
The most optimistic scenario puts a phase 1 clinical trial in humans about 10 years out, but so far, the therapy has passed every test for things like effectiveness and potential long-term toxicity. We don't like to get too excited about research that's this far away from actually changing lives, but we have to admit, it is enormously exciting that this might become a reality within the next decade.