What Causes AIDS?

The debate continues

From the December 1994 issue

(Page 2 of 7)

It is frustrating for me to see Thomas et al. use the fascinating mysteries of this disease to bring fuel to the fire of those who have been hindering a prudent scientific approach to this epidemic.

Daniel Cosgrove, M.D.
Palm Springs, CA

As a scientist, albeit not an expert on AIDS, I would like to explain why I did not find the article by Thomas, Mullis, and Johnson to be very convincing. First, it is no surprise that some people who are HIV-negative fall ill with the diseases associated with AIDS (Kaposi's Sarcoma, certain types of pneumonia, etc.). These diseases are not new. Factors other than HIV virus can damage the immune system and may make individuals susceptible to these, and other, illnesses.

What we have been seeing since the early 1980s is a much larger number of immunodeficient individuals exhibiting a number of hitherto uncommon illnesses, who are also infected with the HIV virus. We also see that a significant number of people lacking the symptoms of AIDS soon develop them after being exposed to the bodily fluids of individuals infected with HIV.

In the absence of any other explanation, simple induction leads us to the conclusion that HIV is either the cause, or part of the cause, of AIDS. True, in the absence of a causal mechanism for AIDS this is not final proof that HIV causes AIDS, but currently it is the best explanation we have.

Second, it is also not surprising that some HIV-positive individuals do not develop the symptoms of AIDS. In the population of millions of HIV-infected individuals, it is to be expected that genetic diversity should ensure that at least some individuals are resistant or even immune to HIV. If this were not so, the plethora of other diseases and plagues that humans were subject to before the discovery of vaccines, antibiotics, and modern medicine would have long since caused our species to become extinct. In this respect, HIV infection should be no different.

If the authors and their intellectual ally, Dr. Peter Duesberg, are convinced that HIV does not cause AIDS, then let them put forth an alternative hypothesis and propose a course of research to determine the true cause of AIDS. Creative research is much more difficult than criticizing the efforts of others.

Ron M. Kagan
Ph.D. Candidate, Biochemistry
University of California
Los Angeles, CA

Is HIV "a conventional retrovirus with a very simple genetic organization"? Well, most retroviruses can get by with three or four genes, whereas HIV has nine. All other viruses in the subfamily to which HIV belongs (the lentiviruses) are responsible for fatal immune-cell disease in animals (sheep, cattle, horses, cats, monkeys), and scientists have not been able to develop a cure for any of these either.

Was the HIV=AIDS dogma established, without scientific foundation, by a press conference? No. Although considerable publicity was attached to a premature announcement by Dr. Gallo in 1984, there was agreement by consensus, not by fiat. The relevant scientific papers were published a few days later in the May 4 issue of the journal Science and served as confirmatory evidence of the strong association between AIDS and a retrovirus similar to one that had been discovered the year before in a wide variety of AIDS patients by researchers at the Pasteur Institute in France.

Several other investigators in this same time period were also in the process of isolating a virus from their AIDS patients (Karpas in England, Rossi in Italy, Francis in Atlanta, and Levy in San Francisco). All of these viruses, initially called by different names, eventually turned out to be variants of the same virus. The name was not standardized to HIV until 1986.

Is there not "even a theoretical explanation for the disease-causing mechanism"? Of course there is. Although the immune response to the initial HIV infection soon eliminates free virus particles from the bloodstream, it is usually unable to eliminate the virus if it has already infected cells in the organs of the lymphatic system. Once there, the virus slowly propagates from cell to cell like a cancer, gradually infiltrating these organs (the lymph nodes, spleen, thymus, tonsils, adenoids, appendix, etc.), many of which are redundant and can withstand a lot of damage before there are any obvious symptoms of impaired function. Blood cells that are susceptible to the virus, called T-helper lymphocytes, continually circulate through the diseased lymphatic organs and are gradually trapped and killed off. The part that is not understood, and for which "increasingly exotic causal mechanisms" have been proposed, is whether the virus kills them directly, or the immune system itself kills them because the mere presence of the virus has made them abnormal.

Are HIV-negative cases of AIDS being ignored or covered up by the medical establishment? Hardly. In 1986, a patient from West Africa with obvious AIDS was found to be negative for HIV. This led to the discovery of a defined AIDS-causing lentivirus now called HIV-2.

Are the opportunistic infections that are characteristic of AIDS sometimes found in the absence of HIV? Of course. They are simply rare in the general population, not non- existent! They were discovered and named long before AIDS came along, and can get the upper hand in anyone whose immune system is temporarily depressed. Thousands of such people "disappear from the official statistics" because they get well, not because the CDC is engaged in some sort of nefarious cover-up.

Nevertheless, since HIV is now so widely used as a diagnostic test for AIDS, the possibility does exist that an epidemic of HIV-negative AIDS could occur without our realizing it from standard statistics. This is why an exhaustive search for HIV-negative patients with profound unexplained immunodeficiency was undertaken in 1992. Less than 100 scattered cases were identified worldwide. They were studied and their disease given a new name (ICL) because their immune abnormalities were found to differ slightly from those typical of AIDS. In any case, the number of such patients compared to the hundreds of thousands of AIDS patients reported around the world is vanishingly small.