HIV has no cure. It’s not quite the implacable scourge it was throughout the 1980s and 1990s, thanks to education, prophylactics, and drugs like PrEP. But still, no cure.
Part of the problem is HIV’s ability to squirrel itself away inside a cell’s DNA – including the DNA of the immune cells that are supposed to be killing it. The same ability, though, could be HIV’s undoing. All because of CRISPR. You know, CRIPSR: the gene-editing technique that got everyone really excited, then really sceptical, and now cautiously optimistic about curing a bunch of intractable diseases.
Last week, a group of biologists published research detailing how they hid an anti-HIV CRISPR system inside another type of virus capable of sneaking past a host’s immune system. What’s more, the virus replicated and snipped HIV from infected cells along the way. At this stage, it works in mice and rats, not people. But as a proof of concept, it means similar systems could be developed to fight a huge range of diseases—herpes, cystic fibrosis, and all sorts of cancers.
Those diseases are all treatable, to varying degrees. But the problem with treatments is you have to keep doing them in order for them to work. “The current anti-retroviral therapy for HIV is very successful in suppressing replication of the virus,” says Kamel Khalili, a neurovirologist at Temple University in Philadelphia and lead author of the recent research, published in Molecular Therapy. “But that does not eliminate the copies of the virus that have been integrated into the gene, so any time the patient doesn’t take their medication the virus can rebound.” Plus treatments can — and often do — fail.
Gene therapy has promised to revolutionise medicine since the 1970s, when a pair of researchers introduced the concept of using viruses to replace bad DNA with good DNA. The first working model was tested on mice in the 1980s, and by the 1990s researchers were using gene therapies — with limited success — to treat immune and nutrition deficiencies. Then, in 1999, a patient in a University of Pennsylvania gene therapy trial named Jesse Gelsinger died from complications. The tragedy temporarily skid-stopped the whole field. Gene therapy had been steadily getting its groove back, but the 2012 discovery that CRISPR could make easy, and accurate, cuts on human genes, added more vigor.
Illustration Credit: Wired