Another Route to a Cure?
One step ahead of elite controllers: people who are immune to HIV infection.
Elite controllers are not the only people able to resist AIDS; within another tiny group, a genetic mutation called delta 32 renders T cells (HIV’s usual targets) impenetrable—and in fact, protects them from becoming infected in the first place. It was stem cells from one of these exceptional individuals that German physicians used to purportedly cure a man of HIV infection, an achievement that was presented to scientists at a think tank at the Massachusetts Institute of Technology in early 2008 and that received widespread publicity following a Wall Street Journal article in November. The results were startling: Almost two years after receiving two stem cell transplants in an attempt to cure his leukemia, the patient, a 40-year-old American who also had AIDS, stopped all HIV medications. With no detectable trace of the virus, he appears “functionally cured” of AIDS, according to scientists at the think tank who reviewed the case.
Though the word cure led to a spate of coverage, prominent AIDS researchers and even the physicians who performed the transplant cautioned against optimism. The rarity of the mutation, the cost of the procedure (around $250,000) and the dangers involved (infection and immune system complications yield a mortality rate as high as 30%) make transplants impractical for addressing the worldwide AIDS epidemic, they say.
However intriguing, the German case represents, at best, a lone victory. In an article on the Website of the Foundation for AIDS Research, Jeffrey Laurence, a physician and senior scientific consultant for the organization, says it’s unknown to what extent delta 32 was actually necessary; it’s conceivable that the very process of undergoing stem cell transplants played a major role in eliminating the patient’s AIDS.
In this case, as with elite controllers, answers may not be known until researchers better understand the basic workings of the immune system and how the virus subverts them.