Antibody treatment joins AIDS battle.

Antibody treatment joins AIDS battle

Antibody injections can help stave off severe bacterial diseases in some children infected with the AIDS virus (HIV), a new study shows.

Because children's immune systems have yet to reach full potency, HIV -- which weakens immunity--leaves them especially vulnerable to bacterial infections such as pneumonia and meningitis. Noting that physicians already prescribe classes of antibodies known as immunoglobulins for other immune deficiencies, researchers reasoned that the same treatment might help HIV-infected children fight these life-threatening secondary infections.

Although the immunoglobulin injections did not improve children's chances of surviving through the entire 21/2-year study, they did reduce the number of hospital stays among the children with less severe HIV infections, reports study director Anne D. Willoughby of the National Institute of Child Health and Human Development. She and her colleagues announced the results at a press conference last week.

The study involved 372 children, 2 months to 12 years of age, at 28 medical centers across the United States. All showed immunologic or clinical symptoms of HIV infection when the study began, and some met diagnostic criteria for AIDS. About half received monthly intravenous injections of purified immunoglobulins (400 milligrams per kilogram of body weight) obtained from healthy adult donors.

To gauge the severity of HIV infection, investigators measured blood levels of white cells called CD4 lymphocytes, which decline as the infection progresses. Among children whose CD4 counts exceeded 200 at the study's beginning, 68 percent of the immunoglobulin-treated group escaped serious bacterial infections for two straight years, compared with 48 percent of the placebo group, Willoughby says. The injections did not appear to help children with CD4 counts below 200.

During the study, many children began taking the antiviral drug AZT to combat HIV or antibiotics to treat bacterial infections, but Willoughby says this did not interfere with the interpretation of the results.

Scientists have no indication that the treatment can boost immunity in HIV-infected adults. Children may benefit from the injections because their immune systems lack reserves of antibody-producing cells. A child's immune system "needs to go to school in a sense," explains William T. Shearer, a pediatric immunologist at the Texas Children's Hospital in Houston.

In a separate study of children with symptomatic HIV infection, researchers led by Philip A. Pizzo of the National Cancer Institute focused on ddI, an experimental drug that targets the virus. They report in the Jan. 17 NEW ENGLAND JOURNAL OF MEDICINE that ddI appears safe and shows "promising" anti-HIV activity in children. They note, however, that its stability in the stomach varied greatly from one child to the next, making dosage requirements tricky to determine. Physicians will need to monitor patients' blood levels of ddI and adjust dosage accordingly, the researchers conclude.