When HIV Doesn't Make You Sick
New Research Shows a Handful of Humans with HIV Can Cope Similarly to AIDS-Resistant Monkeys
May 19, 2011 - For a few people, HIV appears to be just another virus. These rare individuals, called viremic nonprogressors (VNPs), can tolerate high levels of HIV in the body without the immune system going into overdrive. Similarly, some types of Old World monkeys, such as sooty mangabeys, have the ability to withstand infection by SIV, the cousin of HIV, and not end up with crippled immune systems.
A detailed survey of the genes turned on and off in immune cells shows similar patterns in cells from VNPs and from SIV-infected sooty mangabeys. The results were published May 9 in the Journal of Clinical Investigation.
"This result shows that there are parallels between viremic nonprogressors and SIV-infected sooty mangabeys, and confirms the clinical relevance of studying sooty mangabeys as a model of HIV/AIDS," says co-author Guido Silvestri, MD, chief of microbiology and immunology at Yerkes National Primate Research Center, Emory University, and a Georgia Research Alliance Eminent Scholar.
"Previously this wasn't clear because viremic nonprogressors are difficult to identify in the clinical setting and are also relatively rare," says Silvestri.
Scientists at Yerkes, the Ragon Institute of MGH/MIT/Harvard, the Institute of Microbiology in Lausanne, Switzerland, and the AIDS Research Institute in Barcelona, Spain, contributed to the study. The first author of the JCI paper is Margalida Rotger, from the Institute of Microbiology in Lausanne, with co-primary author Steve Bosinger, PhD, an associate scientist at Yerkes. The sooty mangabeys and rhesus macaques in the paper are housed at Yerkes. The senior authors are Amalio Telenti, MD, PhD, director of the Institute of Microbiology in Lausanne, and Javier Martinez-Picado, PhD, from the AIDS Research Institute in Barcelona.
VNPs present almost the mirror image of well-studied "elite controllers," who can beat back HIV and maintain low viral levels for years. VNPs display low immune activation despite high viral levels, all while preserving specific responses against HIV. Of more than 1,000 study participants from Switzerland and Spain, only six fit the criteria for being VNPs.
The authors compared the genes turned on and off in immune cells from VNPs against other individuals with more common responses to HIV infection. They identified a set of "interferon-stimulated genes," whose strong activation usually indicates progression in HIV infection. "These genes tend to have lower activity in VNPs, while, similarly, sooty mangabeys do have an interferon-stimulated gene response. but the key seems to be that they quickly control it," Bosinger says.
The authors write: This work . provides working definitions that should help in identifying additional individuals to allow greater power in future genomic and functional studies.
The link below is to a previous paper that describes VNPs, also referred to as LTA (long-term asymptomatic):
http://www.ncbi.nlm.nih.gov/pubmed/17537849
Writer: Quinn Eastman
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