Many of you may have seen this video floating around Facebook or Twitter, proclaiming that scientists injected a young leukemia patient named Emma with HIV…and it cured her cancer. The tagline of the video reads: “I can’t believe I just watched a team of real doctors inject a 6-year-old girl with a deadly disease… and smiled. Who knew something called a “serial killer” cell could bring so much unforgettable joy and happiness?” But as a blogpost from Cancer Research UK points out, this simply is not the whole story, and the whole focus on HIV as the miracle cure is absolutely wrong. As someone with basic science research experience who actually read the original papers mentioned in the video, I want to take a stab at explaining the science behind these experiments to show you why this story, though definitely news-worthy, is a case of science news gone awry.
The innovative and incredible success story lies in the fact that scientists harvested the patient’s own immune cells, tinkered with them so that they would possess cell surface receptors (CD19) specifically targeting her cancer cells, and then put the cells back into her body. These newly engineered T cells were called “chimeric antigen-receptor modified T cells”, a mouthful which means immune cells with DNA that was altered to target cancer cells. These chimeric T cells then repopulated the patient’s body and actually did what they were supposed to – they attacked and destroyed all of her cancer cells.
The science of engineering autologous (originating from the patient’s own body) cancer killing T cells is relatively new and very exciting in the field of cancer research. Case reports of this technology used to treat 3 patients with Chronic Lymphoid Leukemia were first published in 2011 in Science Translational Medicine and New England Journal of Medicine by the same group led by Dr. June at Children’s Hospital of Pennsylvania. In April 2013, Dr. June published the first case report of this technology being used to treat Acute Lymphoid Leukemia, a cancer affecting children. One of the patients in the case report, though unmentioned by name, is assumed to be Emma, the girl in the video.
So now you are wondering, how does HIV fit into the science of all of this? The answer lies in what the scientists used to make the cancer-killing T cells. To re-engineer Emma’s own immune cells, the scientists had to go back to basics, adding to the actual genetic structure of her T cells. A common method to do this in basic science research is a process called transduction, which takes advantage of a virus life cycle.
The gist of it is that a virus injects its genetic material into a host cell and sneakily incorporates itself into the host DNA to become part of the host cell. The scientists in this case genetically engineered viral genetic information to target cancer cells, and used transduction to get this ability to incorporate into the host cells, which were Emma’s very own immune cells. The result? Superhero T cells that now have this new ability to identify and fight cancer. HIV belongs to a group of viruses called Lentiviruses, which are the perfect vector that scientists tweaked to get the cancer fighting ability into T cells. Lentiviruses have been shown to be the best viruses to get genetic info into host cells, because they can incorporate into non-dividing cells as well as dividing ones. HIV was simply the vehicle for introducing new abilities into Emma’s T cells, and the HIV had been so drastically altered prior to transduction that they could barely qualify as still being “HIV”. They were NOT infectious and did NOT possess the ability to cause disease anymore.
Think about this in superhero terms: Scientists made a magic power that fights cancer. To get the magic power into the superheroes’ bodies (Emma’s T cells), they had to find a tool that grants new powers to superheroes. Pretend this tool originally had a bad reputation, because it was used to put evil powers into superheroes. But today, our scientists completely changed the tool to use it for good, so that it could deliver good cancer-fighting powers. In our scientific story, this tool is HIV.
The science is fascinating, and I love this story because it is a true demonstration of translational research, showing how the physician-scientists took their work from bench to bedside. And it’s an ongoing story, because this chimeric receptor technology can be used to target all types of cancers, not just blood-related ones. I hope this post helps to clarify the real science behind these discoveries, so that you can be a more educated consumer of medical news!