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Early HIV effects on nervous system found.

Early HIV effects on nervous system found

In 1985, when scientists isolated the AIDS-causing human immunodeficiency virus (HIV) in brain tissue and spinal fluid, they realized that the virus directly affected the nervous system as well as the immune system.

But a new study is providing some of the first clues about when HIV begins to affect the nervous system, causing dementia and other impairments. The answer may mean earlier detection and treatment of HIV-infected individuals.

The study, which is the first to detect neurological impairment at various stages of HIV infection, appears in the December ANNALS OF INTERNAL MIDICINE. After giving neurological and psychological tests to a group of 55 homosexual men, Igor Grant and his colleagues at the University of California and Veterans Administration Hospital in San Diego evaluated the subjects' mental abilities and found that HIV appears to have an early impact on the nervous system. In the group with fully developed AIDS, the impairment rate was 87 percent; AIDS-related complex (ARC), 54 percent; HIV positive, 44 percent; and HIV negative (controls), 9 percent.

"HIV may affect brain function early on in infection, but it's premature to make any conclusions from this study," Grant told SCIENCE NEWS.

Other scientists agree with Grant's caution and add that larger longitudinal studies with better controls need to be done.

"In the Grant study, we don't know how long they [the neurologically impaired but asymptomatic subjects] were infected with HIV and how far away they are from ARC," says Richard Johnson, a neuropsychiatric investigator for the Multicenter AIDS Cohort Study (MACS), which involves 5,000 homosexual men in Baltimore, Pittsburgh, Chicago and Los Angeles who were tested for HIV two years ago but who had not developed ARC or AIDS at that time.

At the centers, investigators are monitoring the neurological and psychological characteristics of those who have tested positive for HIV since entering the program. This will help determine when HIV first affects the nervous system and also the effect's prevalence at each stage of infection.

Anthony S. Fauci, director of the National Institute of Allergy and Infectious Diseases (NIAID) in Bethesda, Md., says Grant's study is valid, but better controls are needed. "Psychiatrists have said the anxiety of knowing you're positive for HIV may cause neurological abnormalities, so correct controls would be people who have stress, such as cancer patients."

In a similar sense, some MACS participants who have elected not to know their HIV status are acting as controls, says Johnson, of the Johns Hopkins School of Medicine in Baltimore.

Grant says one implication of his study is that physicians should know that HIV may cause neurological problems in otherwise heaathy patients. "The physician's indext of suspicion must be moved up a notch," Grant says.

In addition, knowing the stage of HIV's impact on the nervous system is important because scientists want to know when to begin therapy with drugs such as zidovudine, which is the only AIDS drug commercially available. But they first must know whether early intervention would be beneficial. The NIAID and zidovudine's manufacturer, Burroughs Wellcome, have set up a study of 1,600 asymptomatic, HIV-positive people to determine the drug's effect.

Because of HIV's apparent effect on the nervous system, U.S. Navy Surgeon General J.A. Zimble in July recommended reassigning flight-crew personnel who test positive for HIV. His recommendation was based on earlier studies that suggested a tie between HIV and neurological problems but that did not specify at what stage of the infection this would occur.
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Title Annotation:human immunodeficiency virus
Author:Eisenberg, Steve
Publication:Science News
Date:Jan 2, 1988
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