Aids Virus Follows Immune System Speeds Up When Body Boosts Defenses Against Infection

Revving up the immune system has the paradoxical effect of boosting production of the AIDS virus in people who carry it and may also make the uninfected more susceptible to HIV, new research suggests.

A study found a temporary surge in HIV in the blood when infected people received a booster shot of the tetanus vaccine.

That shows that when the immune system powers up to fight an infection, the AIDS virus kicks into high gear as well.

The study, led by Dr. Anthony Fauci, head of the National Institute of Allergy and Infectious Diseases, was published in today’s issue of the New England Journal of Medicine

Dr. Warner C. Greene of the Gladstone Institute of Virology and Immunology in San Francisco said in an accompanying editorial that scientists may be able to turn this know- ledge to their advantage. For instance, drugs that suppress the immune system might actually help keep the virus in check.

The work may help explain why an AIDS infection typically progresses much faster to disease and death in such parts of the world as subSaharan Africa, where people’s immune systems are constantly stimulated by parasites and infections.

The AIDS virus principally attacks helper T cells, a crucial arm of the body’s defenses against disease.

In the new study, doctors gave tetanus shots to both people with HIV and uninfected volunteers. Virus levels shot up in all 13 of the infected people. The increases ranged from double to 36 times higher. They reached a peak within two weeks and returned to previous levels after six weeks.

In seven of the 10 uninfected people, the tetanus shots made it easier to infect their blood cells with HIV in the test tube. This suggests that having other infections at the time of exposure to HIV may make people more likely to catch the AIDS virus.