The Business 9/10 May 2004
Why An HIV Test May Not Provide Proof Positive At All
The Critical Flaws In The Methods We Use To Detect The Killer Virus
By Neville Hodgkinson
Legal challenges to the validity of the HIV test,
whose introduction 20 years ago led to the belief that millions of people are
infected with a virus that will eventually cause them to die of Aids, are being
mounted in the United States and France.
In both cases, plaintiffs are citing the work of a group of scientists
Subsequent testing from 1996 to 2003 repeatedly reconfirmed the diagnosis. Today, she remains healthy and free of any symptoms of Aids.
Bannon says that two years
ago, she discovered that the science, methodology and assumptions relied on by
CBC and Roche as the basis for their tests are flawed. She is claiming civil penalties for misrepresentation
and damages for the resulting “mental anguish, pain and suffering, shame and
humiliation” as well as loss of earnings.
She has sold her house to finance the law suit; with the support of her
counsel, Dennis Webb, a
In Paris, Philippe Autrive, a lawyer specialising in health and human rights, has taken up the case of Mark Griffiths, an Englishman living in France who was diagnosed HIV-positive in May 1986 while undergoing treatment for heroin addiction. He still tests HIV-positive but remains well. His complaint, against the Institut Pasteur and others, is for “administering dangerous substances, endangering life, falsification and using falsified material.”
Bannon and Griffiths both say their diagnosis led them
to a journey of discovery in which they became outraged by misunderstandings
over the tests for HIV and the failure of commercial and other interests to put
them right. Griffiths, who has
researched the issue for 16 years, said he hopes his case will lift the “fear,
stigmatisation and ignorance” surrounding a positive test result. Bannon says she spent 10 years “doubting yet
living with the stigma of conventional Aids dogma” before stumbling on an
article by the
“I realise that my life might be more peaceful if I just kept my HIV status under wraps and went on with the knowledge that I’m not going to die from Aids,” she says. “But my soul would not be at peace knowing that so many suffer from the orthodox viewpoint.”
In a series of papers published over more than a
decade but ignored to date by most mainstream Aids experts, the
They cite evidence that in
The group argues that genetic as well as biochemical signals interpreted as meaning the presence of “HIV” are a consequence rather than cause of immune system abnormality. Once this is understood, it says, the grounds for believing that Africans and other impoverished people are in the grip of a devastating new viral epidemic will fall away and help can be directed to fighting the real causes of immune deficiency.
HIV test kits were developed and marketed by US
National Cancer Institute scientists at the same time as the HIV paradigm
itself; the first kits were licensed in March 1985.
The tests do not look directly for an AIDS virus but for HIV antibodies – proteins thought to be produced by the immune system in response to the presence of the virus. They do this by bringing a sample of blood serum (the fluid that separates from blood after it clots) from the person being tested into contact with proteins (antigens) that are believed to be virus components. This should then trigger an antibody-antigen reaction in people who are HIV-infected; but not in those who are not infected.
It could be a valid approach for establishing HIV infection if the proteins looked for by the test really do
specify HIV’s presence; but this has never been shown to be the case. None of the proteins used in the tests has
been shown to be specific for HIV and therefore to mean that a person is
HIV-infected. They have been presumed but never demonstrated to come from HIV
particles. Furthermore, all of the
proteins used in the tests have been shown by the
Central to the
Several steps are essential for identifying retroviruses, the type of virus HIV was supposed to be. The most fundamental is to purify the virus through the use of a filter (a high-speed centrifuge that separates materials of different densities), thus isolating the virus material from other cell constituents. Retroviral particles gather at a specific density. The purified particles can then be visualised and photographed with an electron microscope and their constituents analysed. A final step is to show that they replicate in other cells.
HIV, none of those crucial steps has proved possible. Neither
Yet purification is essential to know which proteins as well as which stretches of genetic material (DNA and RNA) belong to a presumed virus. If the culture materials on which a test is to be based are not pure, test kits made from such materials will be liable to contain proteins of undetermined origin.
According to the
The quandary was expressed clearly by Dr Thomas Zuck,
from the US Food and Drug Administration’s office of biologics research and
review, at a World Health Organisation (WHO) meeting in
Dictated by public health needs, Zuck said, usage had expanded beyond the indications for which the tests were designed; broad application was evident among hospital patients, healthcare personnel and members of groups at high risk of AIDS.
The 100 experts from 34 countries who attended the
meeting heard that, though the tests were sensitive enough to safeguard blood
supplies, something more was needed to distinguish which people had genuinely
been infected with HIV. Dr James Allen,
assistant director for medical science in the US Centre for Disease Control
(CDC) AIDS programme, said studies suggested some people were reacting to
components of the cell line used to grow HIV for many of the test kits licensed
in the US. Other reactions occurred
because of antibodies to normal cell proteins, naturally occurring in the body. Allen warned that the problems could be
magnified in areas of the world that did not have the sophisticated facilities
Several delegates spoke of the need for a definitive,
confirmatory test. They were clear that
a commonly used confirmatory method, called western blot, was not up to the
job. It reduced false positives: surveys
The Elisa kits use a mixture of proteins attributed to HIV. When these react with antibodies in a patient’s serum, a colour change results. The first kits of this kind were made from materials filtered from cell cultures thought to be growing HIV and to be constituents of the virus. It soon became accepted that these materials were not pure virus. They contained normal cell proteins which confounded the test results, falsely producing large numbers of positive results.
The western blot kits are more refined. They use individual test proteins, separated along the length of a strip. These are incubated with the blood to be tested. If the blood contains antibodies to the test antigens, the reactions show up as a series of bands.
The problem is that without having pure virus particles to refer back to, nobody is sure which, if any, of the protein antigens selected for use in the tests really come from HIV and therefore signal HIV infection.
There has been a lot of argument over which proteins should be used and how to interpret the reactions. Even Montagnier and Gallo differ on this. The same uncertainty surrounds later versions of the Elisa test kits, using manufactured proteins rather than the “soup” of materials filtered from cell cultures. These kits overcome the earlier problem of not knowing which antigens were in the kits, but that is not much use when you do not know whether the antigens chosen really belong to HIV.
Dr MV O’Shaughnessy, head of viral surveillance at the
Laboratory Centre for Disease Control,
So, which were viral and which were normal cell components? Several large Canadian studies had shown extensive and generalised cross-reactivity, especially in haemophiliacs and in North American native populations.
Dr John Barbara, head of microbiology at the North
London Blood Transfusion Centre in
Zuck, asked if better tests were in the pipeline, commented: “Don’t hold your breath. One of the difficulties we have in looking at claims for confirmatory tests or designing systems to validate what in fact is going to be ‘confirmatory’ is determining how you define and validate it.”
It was a muddle. At that point, little more than a year into widespread use of the tests, the delegates were frank with one another about the difficulties, though their uncertainties did not enter the public arena except in an expensive specialist textbook. As time went on, and the HIV paradigm won worldwide acceptance, increasingly complex procedures for trying to make a reliable diagnosis came into being. But the basic problem -- not being able to validate any of these procedures against pure virus preparations taken from patients -- still remains.
Next Week: The Deadly Flaws In Diagnosing HIV