Roanoke Times
Copyright (c) 1995, Landmark Communications, Inc.
DATE: WEDNESDAY, August 10, 1994 TAG: 9408100072
SECTION: NATIONAL/INTERNATIONAL PAGE: A1 EDITION: METRO
SOURCE: Associated Press
DATELINE: YOKOHAMA, JAPAN LENGTH: Medium
Perhaps 5 percent of people with HIV, the AIDS virus, show no signs of damage despite 12 or more years of infection. Just how these people stay well has emerged as one of the hottest areas of AIDS study.
Scientists are turning to them for new clues as searches for potential medicines and vaccines repeatedly have ended in disappointment. Researchers hope they can learn what these people's bodies are doing to thwart the virus and essentially bottle it for those less fortunate.
``The long-term survivors, although rare, provide a ray of hope to affected patients and the research community that it is possible to coexist with HIV without harm,'' said Dr. David Ho, head of the Aaron Diamond AIDS Research Center in New York City. He presented his findings at the 10th International Conference on AIDS.
No one knows whether these people will hold HIV in check for the rest of their lives. Still, Ho's study of nine men and one woman infected for between 12 and 15 years suggests powerful internal defenses that show no sign of fading.
Studying long-term survivors ``has enormous potential,'' said Dr. William Paul, director of the U.S. Office of AIDS Research. ``This will be critical in laying out for us what we want to achieve.''
Ho's patients shared no identifiable genetic similarities and were infected in a variety of ways. The only obvious thing they share is a positive attitude toward their infection.
All carried extremely low levels of virus in their bloodstreams, although the virus continued to reproduce. Discovering why is a principal goal of research.
The AIDS virus does its damage by infecting and eventually killing a variety of crucial white blood cells called CD4 cells, which help regulate the immune system.
One early theory was that long-term survivors' CD4 cells were somehow resistant to infection. However, Ho found that HIV actually infects them easily.
Nevertheless, unlike most of those with lengthy AIDS infections, these people do not gradually lose their CD4 cells; their CD4 levels remain normal. Some researchers believe the key to this may be another variety of blood cells called CD8 cells.
In one experiment, Ho combined HIV with CD4 cells taken both from normal volunteers and from long-term survivors. The virus infected the cells and reproduced rapidly.
Then the researchers added the patients' own CD8 cells to the mix. The survivors' cells promptly stopped making virus, but not the volunteers'. This suggests that people who live with the infection are blessed with CD8 cells that are powerful suppressors of HIV.
by CNB