Researchers studying the evolution of the human immunodeficiency virus(HIV) in the brain have found that the body's own defenses may causeHIV-related dementia.
Publishing in the Sept. 2005 issue of the Journal of Virology, theresearchers show that HIV in the temporal lobe mutates at a rate 100times faster than in other parts of the body, triggering white bloodcells to continually swarm to attack the infection. The associatedovercrowding and inflammation appear to cause the dementia.
Earlier studies had suggested that the build-up of white bloodcells could lead to HIV-related dementia, but this is the first studyto track the probable mechanism.
The findings could lead to new treatments that targetHIV-infected white blood cells, perhaps one day countering the brainwasting that will affect as many as 15 percent of the nearly 40 millionpeople around the world who are infected with the virus.
The study is a collaboration among researchers at theUniversity of California at Irvine, the University of Florida atGainesville, Gene Johnson, Inc., of St. Augustine, Fla., the Universityof California at San Francisco (UCSF) and the University of Oxford inthe United Kingdom.
One of the critical tools behind the discovery is HIVBase, agenetic data-storage and -analysis tool with which the researcherstracked the rapidly evolving viruses. Gene Johnson developed the toolwith the support of an NSF Small Business Innovation Research award.
According to co-author Susanna Lamers of Gene Johnson and UCSF,the results strengthen an earlier hypothesis by Kenneth Williams ofHarvard University and William Hickey of Dartmouth Medical School. Theyhad suggested that the continual build-up of white blood cells in thebrain could lead to HIV-associated dementia.
"In our work," says Lamers, "we conducted a thoroughexamination of HIV genetic sequences and were able to prove that theresearchers' concept was a good explanation for both clinicallatency--when the body mounts a strong immune defense and the number ofviral particles decreases--and the long-term damage associated with HIVinfection in the brain. They offered the model, we provided strongevidence that the model is accurate."
Additional information is available in press releases from the University of Florida and Gene Johnson.
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