Proteins Show Promise In AIDS Research

March 30, 1998 Web posted at: 7:45 p.m. EST (0045 GMT)

NEW YORK (CNN) -- A protein found in the urine of pregnant women apparently can stop the reproduction of HIV, the virus that causes AIDS, researchers have learned.

And a new study reported in Monday's Nature Medicine suggests that hemophiliacs who were repeatedly given HIV-contaminated infusions temporarily resisted infection because they had high levels of certain immune system proteins known as chemokines.

The protein found in women's urine during early pregnancy is known as HAF, or human chorionic gonadotropin associated factor. It was discovered by accident by a researcher who was studying Kaposi's sarcoma, a rare but deadly cancer that affects some people with HIV.

When male and female mice were inadvertently put together in a cage, researchers noticed that some of the mice failed to develop the cancer. It was discovered that the cancer-free mice had two things in common: they were female and pregnant.

"It's significant in its potential in that it has broad activity against a number of the pathological aspects of HIV: it directly blocks the virus, it directly suppresses Kaposi's sarcoma, and improves the capability of blood cells to reproduce themselves," said Dr. Anthony Fauci of the National Institutes of Health.

HAF also boosts the immune system by raising the number of T cells, which fight infection, and it prompts the bone marrow to manufacture more blood cells.

The discovery has one additional advantage. Because the protein is produced by the human body, it's non-toxic and has very few side effects.

"These are natural products that haven't been toxic in the concentrations that we used," said Dr. Robert Gallo of the Institute of Human Virology at the University of Maryland. Gallo is one of the researchers who discovered HIV.

Doctors now have to identify the protein molecule of HAF, which they hope to do very soon. If things go as planned, it could be available to patients in as little as three years.

Hemophiliac study

The hemophiliac study focused on 128 hemophiliacs from Italy who were repeatedly exposed to AIDS from blood products between 1980 and 1985, before a test to screen blood for HIV was available.

Only three of the hemophiliacs were initially infected. The total number infected rose in later years, showing that most hemophiliacs have a natural, temporary resistance to HIV, the study said.

Blood cell samples from the hemophiliacs produced about twice as much of three kinds of chemokines as did cells from healthy blood donors, or from hemophiliacs who weren't exposed to HIV.

Prior studies have shown that chemokines can block HIV infection in the test tube, and scientists have been hoping to use them to develop a vaccine or additional drugs to fight AIDS.

The study of hemophiliacs appears in Tuesday's issue of the Proceedings of the National Academy of Sciences. It was originally presented in September by Daniel Zagury of the Pierre and Marie Curie University in Paris, Alessandro Gringeri of the University of Milan in Italy, Gallo and others.

Medical Correspondent Dr. Steve Salvatore and The Associated Press contributed to this report.