Five Quarts_ A Personal and Natural History of Blood - Bill Hayes [108]
Dr. Levy remembers that evening well, though, as he admitted to me in his office, he has never really liked the word cure. “Cure is not the word. Control is the word,” he stressed. Though significantly grayer than when I’d last seen him, Levy spoke with the same certainty. “You aren’t gonna kill every damn cell affected in the body. HIV is a virus like herpes that you have forever. But we will regain control of it.”
To reach this end, Dr. Levy has spent the bulk of his energy over the past seventeen years studying a small pool of research subjects: those rare individuals with HIV known technically as long-term nonprogressors or, more commonly, long-term survivors. Statistics indicate that only about 1 percent of the infected fall into this category.
“We first started to look at these people back in 1986 and found that the virus in them couldn’t replicate,” he recalled. The subjects also had relatively normal white blood cell counts. In those early days, without drug therapy, most people diagnosed with AIDS declined rapidly. “But these were healthy people who showed no signs of infection. And we asked, What’s the secret?”
For answers, Levy, a trained virologist, crossed over to a new turf, immunology. “One of the things with viruses,” he explained, “is that, to survive, they have to exist within a hostile environment.” The brunt of this hostility comes from the body’s natural antiviral response. After HIV invades, antibodies produced by B cells, the fleet of T cells, and other weapons of immunity flood the bloodstream, mounting a formidable defense. But inevitably, in nearly every case, the immune system is soon turned against itself as viral RNA commandeers helper T cell DNA, or, simply put, the helper cells become factories, churning out more copies of HIV.
Not, however, in the bodies of nonprogressors.
In these lucky individuals, Levy found, the internal environment remains antagonistic to HIV, not simply for weeks or years but, in some, for decades. On this topic, I realized I had been operating under a misconception. By virtue of these survivors staying symptom-free, I’d assumed that, within them, all was weirdly peaceful—a milieu wherein HIV and white blood cells quietly coexisted. Don’t bother me, I won’t bother you. Not true. Nonprogressors’ immune systems actually contain supersoldiers whose secret weapon, Levy discovered, is a chemical substance he named CD8 Antiviral Factor, or CAF.
CAF is a protein produced by a type of T cell called the CD8 lymphocyte, or suppressor cell. (These white blood cells don’t “suppress” invading organisms but, rather, inhibit the activity of fellow cells within the immune system.) As Dr. Levy explained, while CAF does not stop HIV from infecting helper T cells, “It blocks the virus so it can’t make its RNA. HIV is shut off by this factor.”
Everyone has CAF, I was glad to hear him say; however, he believes that “only long-term survivors have a capability of maintaining it.” The hope for HIV progressors—my term—is learning how to provoke or rekindle CAF production and maintain it over time.
But first, Jay Levy must actually find this elusive protein. While prominent AIDS researchers agree with him that an antiviral factor is produced by CD8 cells, Levy has yet to isolate it. On the one hand, he and his team can extract a sample of blood from a nonprogressor that contains this factor and can demonstrate in the lab that it does in fact suppress the virus. But where exactly is it? “I can’t yet give you the molecular structure of CAF,” Levy said evenly, the very picture of unruffledness. It is this quality, I realized at that precise moment, that separates the true scientists from the test-tube throwers. Since 1989 the Levy team has been on a molecular scavenger hunt, winnowing the possible proteins