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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 – The Business 9/10 May 2004


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 based in Perth, Western Australia, which has published evidence that contrary to widespread medical belief, none of the HIV test kits is capable of showing a person to be infected.

In Kansas, Calypte Biomedical Corporation (CBC) and Roche Diagnostics, two test kit manufacturers, are being sued for damages under that state’s Consumer Protection Act. In court papers filed on April 12, Kim Bannon says that 12 years ago, during routine medical testing, she was diagnosed “indisputably” HIV-infected at Kansas University School of Medicine. She was told that she would develop Aids within five to seven years and die soon afterwards.

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 Wichita, Kansas attorney, she is inviting others with an “HIV” diagnosis to join her, possibly in a type of class action.

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 Perth scientists.

“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 Perth group has challenged the belief that the HIV test has ever been shown to relate to a specific virus. They say it is a non-specific test that detects raised levels of a variety of protein antibodies commonly found in the blood of Aids patients, but caused by a variety of conditions.

They cite evidence that in Africa and elsewhere, the main causes both of testing positive, and of the immune system deficiencies currently being interpreted as Aids. are poverty-linked diseases such as TB, malaria and other common infections. In the West the causes include the effects of drugs, infections such as hepatitis viruses picked up through needle-sharing and exposure to other people’s body fluids through promiscuous anal sex or repeated transfusions of blood products.

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. France and the UK quickly followed. The kits were introduced as a means of protecting blood supplies, but their use in screening surveys gave rise to the idea that hundreds of thousands of Americans, and millions of Africans and others, were already infected.

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 Perth group to have other potential sources, including normal cell constituents released when immune cells become over-stimulated and disordered.

Central to the Perth scientists’ re-examination of the foundations of the virus theory is their finding that, despite early claims to the contrary, it never proved possible to obtain pure particles of the purported virus, separate from everything else, with which to validate the tests.

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.

With HIV, none of those crucial steps has proved possible. Neither France’s Luc Montagnier nor America’s Robert Gallo, the two scientists who after a long dispute shared the credit for discovering HIV, was able to publish a photograph of purified virus. Nor has anyone else since. The photographs that have been published in numerous newspaper and magazine articles, labelled as showing HIV, are not from purified material. They are from cultures containing a variety of particles emerging from supposedly HIV-infected cells; but these particles are of unspecified character and similar particles appear in cultures of non-infected cells as well. When the next step is taken — trying to filter particles to identify them and characterise them — experts have never been able to obtain pure HIV.

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 Perth group, and growing numbers of scientists who support their position, that is exactly what happened with HIV. But because of political pressures, and a general sense of panic about Aids, regulators allowed the tests to come into use in ways that they knew were inappropriate. It was felt that the public health benefits outweighed the disadvantages.

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 Geneva in 1986. He said the first test kits, using a technology known as Elisa, were licensed as a screen to protect blood and plasma donations, not as a screen for AIDS or people at risk of AIDS; their usage was intended to be limited by phrases to that effect in the package inserts. But “enforcing the intent of this language would be analogous to enforcing the Volstead Act, which prohibited alcoholic beverage sales in the United States in the 1920s – simply not practical.”

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 of the United States.

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 in the US showed that, of blood donors who tested positive with the most commonly used Elisa kits, only about 4% were confirmed with western blot. But were any of those 4% truly infected?

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, Ottawa, Canada, told the WHO meeting that when the proteins from an HIV preparation were separated and stained using ultra-sensitive techniques, “more than 30 individual proteins can be recognised.”

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 Britain, pointed out that both tests relied on the same principle, of antigen-antibody reactions. “It is important to remember that the western blot is itself an antiglobulin assay [a test for antibodies. It is liable, therefore, to the same kind of false-positive reactions as the screening test it might be confirming.” In other words, if there was uncertainty over whether the first test gave valid results, a second test based on the same principle could hardly be used to confirm the other.

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

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