By Robert Root-Bernstein
Street Journal 17 March 1993
As one of a
small but growing group of AIDS heretics, I was very pleased to
see that the recent National Research Council report on AIDS challenged
the orthodoxy. It said that HIV infection and AIDS will remain limited
to specific geographic areas and risk groups identified at the beginning
of the epidemic: gay men and more particularly an ever-growing population
of urban, drug-addicted, poverty-ridden, malnourished, hopeless
and medically deprived people.
and social implications of the National Research Council report
have received massive press coverage over the past few weeks. But
it is the scientific and medical implications, unaddressed in the
report, that are truly revolutionary. As the World Health Organization's
working group on AIDS pointed out in 1984, if everyone is not equally
susceptible to AIDS, factors other than HIV alone must govern who
becomes infected and whether infection results in disease. This
basic medical principle is as old as the germ theory of disease
There is absolutely
no doubt that some people are much more susceptible to HIV and AIDS
than are others. Perhaps the most striking data concern female prostitutes
in Western nations. Early in the epidemic, it was assumed that female
prostitutes would become the vectors by which HIV and AIDS would
be spread to the heterosexual community. A single, HIV-infected
female prostitute might, it was thought, infect dozens of heterosexual
men, and equal numbers of women through these men.
In fact, between
5% and 10% of female prostitutes are HIV-infected in major U. S.
cities such as Los Angeles and New York. But there are two striking
facts about these prostitutes. First, HIV-infected prostitutes,
with only a few exceptions, are intravenous drug abusers. Cases
of sexually acquired HIV among drug-free prostitutes are almost
unknown. Second, in literally only a handful of cases are female
prostitutes thought to have transmitted HIV to a client, and drug
abuse by both the prostitute and the client has been documented
in almost all of those cases.
every major review of female prostitution by the medical authorities
of Western nations has concluded that drug-free female prostitutes
are not susceptible to HIV and are not, and will not be, the means
of infecting the general population. Immunologically healthy individuals
seem to be immune. This is hardly the behavior expected of a typical
sexually transmitted disease.
that AIDS is controlled by more than just HIV comes from studies
of the development of disease following active HIV infection. The
average time from infection to overt AIDS (based on studies of gay
men and intravenous drug abusers) is 10 years. If HIV alone controlled
AIDS, then about half of the people infected with HIV in 1983 should
have developed AIDS by now, regardless of their mode of exposure.
Yet this is not true of hemophiliacs.
It is estimated
that 90%, or some 15,000, of the hemophiliacs in the U. S. were
infected with HIV between 1981 and 1984. One would expect at least
half of these hemophiliacs to have developed AIDS by now. But only
1,500 cases of AIDS have been recorded among hemophiliacs during
the entire epidemic. Moreover, hemophiliacs under the age of 20
and those with less severe manifestations of hemophilia progress
to AIDS at a fifth the rate of older and more severe hemophiliacs.
If anything proves that HIV alone does not control the development
of AIDS, this is it.
An even more
striking fact is that, like female prostitutes, hemophiliacs have
not become vectors for spreading AIDS into the heterosexual population.
So-called secondary cases of AIDS, in which a person not in a primary
risk group acquires AIDS from someone in such a group, constitute
only 3% of all AIDS cases ever reported in the U. S. Cases of AIDS
transmitted by hemophiliacs total only 104 (as of January 1992),
and most of the affected individuals have documented assaults on
their immune systems beyond HIV exposure.
of AIDS are completely unknown. No documented case of AIDS exists
anywhere in the Western world of a drug-free heterosexual who contracted
AIDS from a primary carrier (for example, a hemophiliac) and then
transmitted the disease to a healthy, drug-free third party. Again,
this phenomenon is unparalleled in any previous epidemic.
and hemophiliac data argue strongly for the conclusion that healthy,
drug-free people do not get AIDS. The people who do get both HIV
and AIDS have many additional immunosuppressive factors at work
on them that predispose them to disease. These include:
autoimmunity following unprotected anal intercourse.
- Blood transfusions
or infusions of blood-clotting factors.
use of recreational and addictive drugs.
or high doses of many antibiotics, antivirals and antiparasitics,
anesthetics, opiate analgesics or steroids.
- A particular
type of autoimmunity, in which one part of the immune system is
triggered to attack the same T cells that are the target of HIV
with AIDS for whom there is sufficient documentation has some subset
of these risk factors. Consider, for example, the immunologic risks
of blood transfusion patients. It is often said that their only
risk of AIDS is HIV. But they would not need a blood transfusion
unless they were already at death's door. The blood that they receive
itself suppresses their immune systems; the greater the amount of
blood transfused, the greater the immunosuppression. If the blood
contains HIV or other viruses, such as cytomegalovirus, Epstein-Barr
virus, or one of the hepatitis viruses, there is additional suppression
of the immune system.
receive transfusions because they require surgery. Surgery and the
anesthetics that accompany surgery suppress the immune system. So
do the opiate analgesics (e.g., morphine) and the high doses of
antibiotics that are very often prescribed afterward. In some cases,
the transfusion triggers an immunologic civil war in which antibodies
attack white blood cells. Individually, none of these factors would
cause AIDS, but together they can prove deadly.
drug addicts have many more immunologic risks than simply HIV acquired
from shared needles. The drugs they use often suppress the immune
system. Most addicts are concurrently infected with a variety of
viruses, including hepatitis viruses; bacteria; and recurrent sexually
transmitted diseases. The majority chronically abuse antibiotics
obtained through their drug dealers, and are therefore much more
likely than the average person to acquire drug resistant strains
of infections, such as tuberculosis. Most have autoimmune conditions
in which their antibodies target their white blood cells. Most are
malnourished, some severely so, and do not have the nutrients required
to mount an effective immune response.
if the blood transfusion patient or drug addict is pregnant, she
may pass on not only HIV, but all of her immunosuppressive risks
to her infant. The fetus, too, is exposed to the transfusion, the
anesthetics, the drugs, the malnutrition, the viruses and sexually
transmitted diseases, the antibiotics. It even inherits its immunity
for the first few months of life from its mother, and therefore
inherits impaired immunity if that is all the mother has to offer.
AIDS, in short,
is more than just HIV. This conclusion is both scary, in that we
must recognize that we have been addressing only part of the cause
of the epidemic, and it is exciting, because it gives us new targets
for controlling AIDS.
indicate that eliminating risk factors for HIV-infected people can
be more effective in preventing the development of AIDS than treating
HIV. Swiss and Italian studies, for example, show that eliminating
drug use and malnutrition among HIV-infected addicts slows their
rate of progression to AIDS by an average factor of three to 10
compared with addicts who continue to abuse drugs. Many of the drug-free
former addicts have remained healthy.
purifying blood-clotting factors for hemophiliacs has been extremely
beneficial. Blood-clotting factors normally are made from the blood
of hundreds or thousands of donors and inevitably contain huge amounts
of cellular, viral and other contaminants. The new ultrapurified
or recombinant-DNA-produced factors have totally stabilized immunologic
functions in all of the treated hemophiliacs. Many of these HIV-infected
hemophiliacs have even had their immunologic functions return to
the factors that make one susceptible to HIV and AIDS may therefore
turn out to be easier and more effective than targeting HIV itself.
This is the medical implication of differential susceptibility to
AIDS. It is time we recognize its importance. *
is an associate professor of physiology at Michigan State University
and author of "Rethinking AIDS," just out from Free Press.