April 1, 1998
Gene therapy a new frontier in HIV fight
By Lisa Krieger
OF THE EXAMINER STAFF
THIS WEEK, Bay Area volunteers are participating in the first study of the safety and
feasibility of genetically modified blood cells designed to fight HIV infection.
Patients receive an infusion of their own cells, which have been modified to include a mutant
gene that interferes with the ability of HIV to reproduce. The experiment is being conducted by
the AIDS Community Research Consortium in Redwood City.
"Gene therapy is a potentially exciting
new approach to treating a number of
diseases that have resisted treatment in the
past, including HIV infection and various
cancers," said Dr. Stan Deresinski,
principal investigator of the study.
Jacqui Sheffield is a study participant.
When she was diagnosed with HIV, she
said to herself, "AIDS equals death.
That's what I thought. I immediately
thought about my beautiful son and I
began to imagine not being able to see him
grow up. After months of feeling sorry
for myself, I decided to take action."
Now she is taking combination therapies
and volunteering in the gene therapy
study. Her participation will help
scientists understand the process of
"harvesting" blood cells called stem cells,
which are the primary generators of
immune cells that fight disease. The consortium trial is the first to test the potential of stem
cell-based gene therapy.
"I wanted to take part in some of the newer approaches to treat HIV infection, so that some day
all patients may be helped," Sheffield said.
Chemokine protection
Fourteen hemophiliacs who were repeatedly exposed to HIV resisted infection because they
had high levels of immune system proteins called chemokines, a study suggests.
The study involved 128 hemophiliacs who had repeatedly been exposed to HIV from blood
products from 1980 to 1985. Only three were infected by the first infusions. The total number
of those infected rose to 59 in 1982, 84 in 1983, 103 in 1984 and 114 in 1985.
The pattern shows that most hemophiliacs had a natural -- but temporary -- resistance to HIV
infection, The Associated Press reported.
Blood cells taken from them were found to produce about twice as much of three kinds of
chemokines as did cells from healthy blood donors, or from hemophiliacs unexposed to HIV,
according to the research, reported by Dr. Daniel Zagury, of the Pierre and Marie Curie
University in Paris; Alessandro Gringeri, of the University of Milan in Italy; and Dr. Robert
Gallo of the Institute of Human Virology at the University of Maryland in the latest issue of the
Proceedings of the National Academy of Sciences.
Prior studies have shown that chemokines can block HIV infection in the test tube, and
scientists have been hoping to use them to develop AIDS drugs or a vaccine.
Monkey viruses
U.S. researchers reported this week that they have evidence that people can be infected with
monkey viruses -- including one laboratory worker who got infected with SIV, the monkey
equivalent of the HIV virus that causes AIDS in humans.
The findings have implications for research into xenotransplants, animal-to-human organ
transplants, said researcher Walid Heneine of the U.S. Centers for Disease Control and
Prevention, who reported his findings in the journal Nature Medicine.
Heneine tested the blood of 231 lab workers who handled monkeys and found that five had
become infected with monkey viruses. One was SIV and four were infected with a simian
foamy virus, common in laboratory monkeys.
They were not harmful in any of these people, he said.
But researchers fear that people given an organ of an animal might catch an animal virus that
turns dangerous.
"The impact on xenotransplants is that, yes, we have documentation that people who receive
xenotransplants from SIV-infected baboons may very likely get infected with SIV virus, but
we don't have any evidence that it will harm them," Heneine told Reuters.
The viruses came from an African green monkey and from baboons. All the infected lab
workers reported suffering injuries, such as bites from the monkeys.
But the workers did not get sick. Nor did their spouses. Tests of old blood donated by the
workers found that one was infected for at least 20 years and another for nine years.
Robin Weiss, an expert in viruses at the Institute of Cancer Research in London, said viruses
have been hopping from animals to humans for generations, but rarely cause an epidemic.
HIV, thought to have mutated from SIV, is a major exception.
But he added in a commentary in Nature Medicine that "we understand all too little about what
allows viruses to adopt and spread in a new host."
New test
The government is recommending use of a new HIV test that yields results instantly instead of
a week later.
The CDC says the rapid test will address a major drawback of the current method: Nearly
700,000 people a year never return to find out their test results. And because they are tested
anonymously, there is no way for clinics to call and inform them of their infection.
The new test means that more people will be able to get prompt education and treatment.
"Most people either don't want to or are afraid to deal with it unless they become sick," said
Tony Braswell, executive director of AIDS Atlanta. "If you can tell someone while they are
sitting there, talking with a counselor, you could get a head start with them . . . and tell them
that their life is not over."
The test, manufactured by Murex of Norcross, takes about 10 minutes to determine whether
the virus is present. Both the new and the old tests look for antibodies in the blood. However,
the traditional, one-week test also looks for specific protein bands, which are considered the
absolute indicator of HIV.
About 8,000 people annually would initially receive false-positive results from the new test,
said Bernard Branson of the CDC. In contrast, the current one-week test is nearly 100 percent
accurate.
To combat false results, clinics give three quick HIV tests. If one or more comes back with a
positive reading, a traditional blood test is taken and the results are made available in about
seven days.
The toll
Jon M. Gilreath, 46, a Phi Beta Kappa graduate of Michigan State University with an MBA
from UC-Berkeley who then became an executive at California Public Radio and Pacific Bell .
. . Douglas A. Smith, 50, a Massachusetts native who was director for the Social Security
Administration for 24 years.
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