MEDICINE

What causes AIDS?

Scientists question the accepted theories

TOM FENNELL June 1 1992
MEDICINE

What causes AIDS?

Scientists question the accepted theories

TOM FENNELL June 1 1992

What causes AIDS?

MEDICINE

Scientists question the accepted theories

In 1983, French scientist Luc Montagnier’s discovery of a virus widely believed to cause AIDS elicited an outpouring of optimism among researchers seeking a cure for the disease. Many of them predicted that a vaccine to control the deadly human immunodeficiency virus would soon be produced. Governments began spending billions of dollars on research into the virus and on public health campaigns aimed at limiting the spread of HIV. But now, a growing number of scientists, including Montagnier himself, have begun to question the role of HIV in the spread of AIDS. While officials of the World Health Organization estimate that about 12 million people in the world are currently infected with HIV, many scientists now suspect that the virus alone may not be responsible for AIDS. Other contrarian theorists, including Peter Duesberg, a professor of molecular and cell biology at the University of California at Berkeley, go even further in debunking current thinking on

the causes and transmission of AIDS. Duesberg, who maintains that HIV has nothing to do with AIDS, has been shocking public health officials recently by declaring that heterosexuals who are not intravenous drug users can safely have multiple seit partners without facing a high risk of contracting AIDS. In fact, Duesberg told Maclean’s last week: “There is no evidence that AIDS is an infectious disease.”

While most mainstream AIDS researchers reject Duesberg’s position, scientists working in the field are dividing into three distinct camps on HIV’s role in AIDS. Those in the first group say that Hiv, acting by itself, triggers the onslaught of AIDS, which destroys the human immune system and is always fatal. Scientists in a burgeoning second camp contend that HIV plays a critical role in causing the cells in the body’s immune system to attack themselves, possibly in combination with other micro-organisms. Duesberg leads a third group that claims that, although HIV is present in many

AIDS patients, it does not cause the fatal disease.

While some Canadian scientists have begun to work on the assumption that factors other than HIV may be involved in the development of AIDS, most of them reject the extreme third position. Said Mark Wainberg, director of the AIDS Centre at Montreal’s McGill University: “To say that HIV is innocuous is reprehensible and irresponsible. It certainly is a necessary component in the development of AIDS.”

Still, some of the arguments put forward by the dissident AIDS scientists appear to be gaining credibility. Last month, a British government-supported medical body announced that it would fund research aimed at showing that HIV does not directly cause AIDS. And in midMay in Amsterdam, more than 200 scientists, physicians and patients met at an international conference titled AIDS: A Different View. Montagnier, who told the meeting that he is reassessing the role of HIV in the development of AIDS, said that the virus may be sent on its destructive course in the human body by changes in micro-organisms in the body known as mycoplasmas. Mycoplasmas are common parasites in human tissue that some researchers believe may play a role in causing AIDS. As well, Robert Root-Bemstein, associate professor of physiology at Michigan State University in East Lansing, said that the mycoplasmas, along with HIV, may cause the immune system to destroy itself in AIDS patients.

Another claim by Duesberg—that AIDS in the Western world is caused by drug abuse and some homosexual behavior—has caused a storm of controversy. Duesberg, who has vol-

unteered in the past to inject himself with HIV to prove that it does not cause AIDS, said that the real cause of the disease is the repeated shocks to the body’s immune system caused by recreational drug abuse, certain medicines prescribed to fight the disease and, in Africa, poor nutrition and sanitation.

He said that during the past 20 years, drug abuse has soared, particularly among homosexual males who, according to Duesberg, use amyl nitrite, amphetamines and other moodaltering drugs to boost their energy levels during sex. Duesberg said that drug abuse damages the immune system, leaving it susceptible to hundreds of micro-organisms, including the hepatitis virus. Eventually, after several years of drug abuse, he argues, an individual’s immune system is overwhelmed and collapses, “AIDS is being spread in the West by recreational drug abuse in the homosexual community,” said Duesberg. “In nearly every AIDS case, you find evidence of drug abuse.”

Some of Duesberg’s controversial opinions are shared by the University of Michigan’s Root-Bemstein, who said that many microorganisms, or so-called co-factors, may be working in conjunction with HIV to cause AIDS. Like Duesberg, he said that the immune system may collapse because of continued abuse from addictive drugs or even some medical treatments, such as blood transfusions.

Root-Bernstein also supports the controversial theory that the act of anal intercourse may traumatize the body's immune system and cause disease-fighting white blood cells to attack one another. He said that, in laboratory tests, the immune system of mice collapsed

when foreign semen was injected into their rectums. Added Root-Bemstein: “It is very well documented that semen can suppress the immune system, but whether it is sufficient to cause AIDS still needs more investigative work.”

In Canada, many AIDS researched and activists rejected Duesberg’s and Root-Bemstein’s theories. They say that when safe sex is practised, the spread of HIV and the resulting number of AIDS cases appears to slow. Said Richard Burzynski, executive director of the Ottawabased Canadian AIDS Society, a govemmentand privately funded umbrella organization for community AIDS agencies: “Nothing that Duesberg has said has changed our opinion on HIV.”

But in Amsterdam, Montagnier, one of the most respected scientists in the field, spoke of his misgivings at having AIDS research focused so exclusively on his discovery, HIV. “There are too many shortcomings in the theory that HIV causes all signs of AIDS,” Montagnier told the conference. “We have some laboratory results that indicate the killing effect of HIV very much depends on the presence of cofactors.” Now, the search to identify and isolate the co-factors that may be involved in AIDS is gaining momentum. In Britain last month, the Medical Research Council agreed to fund new research that seeks to show that AIDS is not directly caused by HIV. And British researchers say the government decision to explore alternative research is a clear indication that I the move towards finding an explanation for tne cause of AIDS is gathering momentum.

Members of the research organization involved, the Human Immunodeficiency Virus Epidemic Research group in London, say that while HIV may trigger AIDS, the disease occurs because the body’s own immune cells deteriorate and attack one another. Said senior re-

searcher Angus Dalgleish: “Previously, the whole scientific community seemed to believe without question that because immune cells were destroyed after thè virus was found to be present, then it must have been the virus that was killing them.” The London group wants to develop a vaccine that would redirect the immune system in AIDS patients so that antibodies attack HIV, and not the immune system.

In Vancouver, Geoffrey Hoffmann, a theoretical physicist at the University of British Columbia, views the role of HIV somewhere between Duesberg’s position that it has no impact and Montagnier’s growing suspicion that HIV is influenced by mycoplasmas. In his research, Hoffmann is trying to show that when HIV penetrates the body’s disease-fighting T-cells, the immune system springs into action. But he shares balgleish’s opinion that, in battling the virus, the cells also turn on the immune system itself and attack the body.

Michael O’Shaughnessy, head of the Vancouver-based B.C. Centre for Excellence in AIDS/HIV, which is funded by the province of British Columbia, says that he will soon begin a series of experiments on HIV-infected blood samples that will be aimed at investigating the possible role played by micro-organisms as cofactors in the onset of AIDS. O’Shaughnessy said that such research is still highly speculative, because it is difficult to establish a cause1 and-effect relationship between HIV and other micro-organisms. Said O'Shaughnessy: “We will need to know a lot more more about cofactors before we can say anything. And that will take a lot of work.”

At the same time, McGill’s Wainberg, who maintains that AIDS does not occur without HIV, added that there is growing pressure to recognize that other factors may influence how HIV reacts in the human body. Declared Wainberg: - “We know about genetic elisia away> abilities in which people have very little ability to produce an immune response. And we know that people who are undernourished have a poor immune response.”

But for many Canadians on the front lines in the international battle against AIDS, controlling HIV remains the primary goal. Dr. Allan Ronald, a University of Manitoba physician who is taking part in a program aimed at slowing the spread of AIDS in the African nation of Kenya, said that HIV is nearly always present in AIDS victims. According to Ronald, Duesberg and other theorists are merely part of a “radical fringe” that eventually “will go away.” But for now, the debate over the radical new theories on AIDS simply shows how poorly understood the disease still is.

TOM FENNELL