Philadelphia — Adolescents infected with HIV were found to have a surprisingly high number of certain immune system cells, according to a research team led by an immunologist at The Children’s Hospital of Philadelphia. In studying 94 HIV-positive patients, aged 13 to 19, the researchers found a "striking increase" in the number of circulating CD8 memory cells, which play a major role in attacking the virus that causes AIDS.
The study offers intriguing hints of how the immune system of adolescents differs from those of younger children and adults, according to the study’s lead author, Steven D. Douglas, M.D., Chief of Immunology at Children’s Hospital, and co-author Bret Rudy, M.D., of the same institution. Although adolescents represent the largest segment of the U.S. population newly infected with HIV, relatively little is known about the relative proportions of different blood cells in teenagers’ immune systems. The study, published in the September 1999 issue of the journal AIDS, is the first attempt to establish reference measurements for cells that act as immune system markers for both HIV-infected and healthy adolescents. At the time of the study, the infected teenagers had not been treated with the antiretroviral medicines commonly used against AIDS.
The researchers also found significant differences in immune system cell populations between male and female adolescents. These differences may be related to hormonal and developmental changes that occur during adolescence. Future studies will explore how the immune system of adolescents functions during HIV infection.
Blood samples were drawn from 243 HIV-positive and HIV-negative adolescents at 16 clinical sites throughout the United States participating in the Adolescent Medicine HIV/AIDS Research Network, established by the National Institutes of Health and the Health Resources and Services Administration. As part of that network, the REACH Project (Reaching for Excellence in Adolescent Care and Health) performs research and provides medical care for adolescents who are infected with HIV and those who are uninfected but at high risk for the infection because of their behavior and social situation.
The study was co-sponsored by the National Institute of Child Health and Human Development, the National Institute of Allergy and Infectious Diseases, the National Institute of Drug Abuse, the National Institute of Mental Health, and the Health Resources and Services Administration.
Addendum to reporters:One co-author of the study, Bret Rudy, M.D., also of The Children’s Hospital of Philadelphia, is national co-chair of Project ACCESS, a social marketing campaign that will target the message, "HIV. Live with it. Get tested!" to at-risk young people in African-American and Latino communities in six cities: Baltimore, Los Angeles, Miami, New York City, Philadelphia and Washington. Combining an advertising campaign with community-based events, the campaign will be launched on October 25. Project ACCESS is part of the Adolescent Medicine HIV/AIDS Research Network. More information on the campaign is available through the Department of Public Relations, The Children’s Hospital of Philadelphia, through Maria Stearns, (215) 590-4091.
Materials provided by The Children's Hospital Of Philadelphia. Note: Content may be edited for style and length.
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