Theory on AIDS ‘Co-Factor’ Debated
AIDS researchers Thursday debated a controversial theory that simultaneous infection with the human immunodeficiency virus and small bacteria-like organisms called mycoplasmas helps explain why some people infected with HIV quickly become seriously ill with AIDS, while others remain healthy for years.
The theory has been given credence in recent months by data from the laboratory of Dr. Luc Montagnier of the Pasteur Institute in Paris, the co-discoverer of the AIDS virus, who presented some of his findings for the first time at the international AIDS conference here.
“There are shortcomings in the theory that HIV causes all the signs of AIDS,” said Montagnier, who has become convinced that the virus requires a “co-factor,” such as mycoplasmas, before it can wreak havoc on the human immune system.
But other leading scientists, such as Dr. Jay Levy of UC San Francisco, argue that the AIDS virus itself mutates over time in the body to more virulent forms that overwhelm the immune system. Levy called Montagnier’s conjectures “premature.”
If the mycoplasma theory is correct, then conventional antibiotics--which can kill mycoplasmas but not the AIDS virus--might be used to stabilize the condition of those individuals infected with both germs. But Montagnier does not advocate such an approach outside of experimental trials, citing insufficient evidence that it works and the possibility that antibiotic-resistant strains of mycoplasma will develop.
Mycoplasmas share similarities with bacteria, but are smaller and are covered by a thin membrane instead of a cell wall. Like other microbes, they are ubiquitous in the environment.
In humans, one species of mycoplasma transmitted through the air is a common cause of pneumonia, while another sexually transmitted species causes genital infections. Many species of mycoplasmas, some of which frequently contaminate laboratory cultures, are not believed to cause human disease.
While acknowledging that his data remains more suggestive than conclusive, Montagnier said in presentations Wednesday night and Thursday that he had found evidence of mycoplasma infection in the blood of 37 of 97 patients with AIDS and related conditions, including gay men, intravenous drug users and those infected with AIDS through blood transfusions.
Montagnier acknowledged that actual mycoplasma organisms have been isolated only in a handful of patients. He also did not present data on how or when AIDS patients might be infected with mycoplasmas. But he added, “It was very unlikely that this (mycoplasma infection) was contamination” of laboratory cultures.
Other researchers viewed the data skeptically. “The data is too minimal, so general conclusions are difficult,” said Levy of UC San Francisco.
Dr. Dolph Druckman, an AIDS physician at DC General Hospital in Washington, said Montagnier’s data “represents an interesting observation” but that the role of mycoplasma in causing “significant immunodeficiency” is “questionable.”
In a separate study, Montagnier said that 21 AIDS patients had been treated with antibiotics, such as tetracycline, for three months. One-third had “some clinical improvement,” such as weight gain and loss of fever. The others remained the same or became more ill. But he cautioned that these tests were conducted before he discovered that the mycoplasmas he found in AIDS patients were frequently “resistant” to tetracycline and that further tests would be necessary with other antibiotics.
Nevertheless, Montagnier said that “antibiotic treatment (against) mycoplasma will not be sufficient to improve the condition of most of the AIDS patients.”
In another presentation Wednesday night, Dr. Shyh-Ching Lo of the Armed Forces Institute of Pathology in Washington elaborated on his controversial theory that a previously unrecognized mycoplasma can cause potentially fatal diseases in both AIDS patients and healthy uninfected individuals, such as kidney, heart, spleen and brain infections.
The mycoplasma Lo has studied, called Mycoplasma incognitus, apparently is similar to one of the germs Montagnier has identified, called Mycoplasma fermentans.
But many scientists are uncertain how to reconcile the two theories.
