Updated at 6:27 p.m. ET on December 19, 2018.
When the nurse slipped the IV needle into his arm, Matt Sharp was calm. Yes, he knew the risks: As one of the first humans ever to receive the experimental treatment, he could end up with mutant cells running amok in his body. But he was too enamored of the experiment’s purpose to worry about that. For two decades, Sharp had been living with HIV. He’d watched the height of the AIDS crisis claim dozens of his friends’ and lovers’ lives. Now, he believed he was taking a step toward a cure.
A few months earlier, researchers had drawn white blood cells from Sharp’s body and manipulated his DNA with tiny molecules, deleting a single gene in each cell. He was about to receive an infusion that would reintroduce the tweaked cells back into his bloodstream. The procedure aimed to change the genetic makeup of these cells to make Sharp’s body resistant to HIV. Gene therapies like this had been tried before for other diseases, but experiments were put on hold when a young man died in 1999. Sharp’s body would allow researchers to test the safety of new molecular tools called “zinc fingers.”
The infusion took place in June 2010 at Quest Clinical Research, a nondescript gray building near The Fillmore in San Francisco. Sharp’s cells arrived frozen in a liquid-nitrogen-filled shipping container that looked like R2-D2 from Star Wars. After thawing them in a hot-water bath, his nurse plugged the bag into his IV line. Cloudy yellow fluid slowly drained into Sharp’s arm. Within 30 minutes, he headed back to work with billions of genetically modified cells reproducing in his arteries and veins.