BIO/TECHNOLOGY
VOL.11 JUNE 1993 - vedi:
Test fraudolento
+
L'altra storia dell'Aids +
Hiv
virus inventato
Is a Positive Western Blot Proof of HIV
Infection ?
Eleni Papadopulos-Eleopulos, Valendar F. Turner and
John M. Papadimitriou
It
is currently accepted that a positive Western blot (WB) HIV antibody test is synonymous
with HIV infection and the attendant risk of developing and dying from AIDS. In this
communication we present a critical evaluation of the presently available data on HIV
isolation and antibody testing. The available evidence indicates that: (I) the antibody
tests are not standardised; (II) the antibody tests are not reproducible; (III) the WB
proteins (bands) which are considered to be coded by the HIV genome and to be specific to
HIV may not be coded by the HIV genome and may in fact represent normal cellular
proteins; (IV) even if the proteins are specific to HIV, because no gold standard has been used and
may not even exist to determine specificity, a positive WB may represent nothing more than
cross-reactivity with the many non-HIV antibodies present in AIDS patients and those at
risk, and thus be unrelated to the presence of HIV. We conclude that the use of the HIV
antibody tests as a diagnostic and epidemiological tool for HIV infection needs to be
reappraised.
"...we are not simply contending in order that my
view or that of yours may prevail, but I presume we ought both of us to be fighting for
the truth..."
From Philebus, the Dialogues of Plato
To
date, the only routinely used methods for demonstrating the presence of HIV in vivo are
the ELISA and WB antibody tests. In the ELISA, the "HIV proteins" are present as
a mixture. For the WB, the HIV proteins are dissociated and placed on a polyacrylamide gel
slab. After electrophoresis, which separates the proteins by molecular weight and
charge,
the proteins are transferred to a nitrocellulose membrane by electroblotting.
In performing the antibody test, in both ELISA and WB, the patient's serum is added to the
antigen preparation.
It is assumed that if HIV antibodies are present, they will react
with the HIV proteins which, after washing, are visualised by an enzyme
anti-human-immunoglobulin chromogen reaction. In the ELISA the reaction is read
optically.
For the WB, individual proteins are recognised and interpreted visually as coloured
bands,
each of which is designated with a small "p" (for protein), followed by a
number, (which is the molecular weight in kilodaltons), for example p41.
The
WB is believed to be highly sensitive and specific, and a positive result is regarded as
synonymous with HIV infection. A positive HIV status has such profound and far reaching
implications that no one should be required to bear this burden without solid guarantees
of the verity of the test and its interpretation. In this paper, the evolution of the
antibody tests, the basis of their specificity, and the validity of their interpretation
are evaluated.
Acceptance of an antibody test for HIV as being scientifically valid and
reliable requires the following: (I)
A source of HIV specific antigens; (II)
Standardisation; (III) Determination of the test's reproducibility.
Once these criteria
have been met, and before the introduction of the antibody tests into clinical medicine,
the test's sensitivity, specificity and predictive values must be determined by the use of
a gold standard, HIV itself.
Proteins
Considered to be HIV Antigens
The
proteins considered to represent HIV antigens are obtained from mitogenically stimulated
cultures in which tissues from AIDS patients are co-cultured with cells derived from
non-AIDS patients-usually established leukaemic cell lines. Following the detection of the
enzyme reverse transcriptase (RT) in the cultures, the supernatant, and more often the
cell lysates, are spun in density gradients. Material which bands at 1.16 gm/ml is
considered to represent "pure HIV" and consequently the proteins found at that
density are considered to be HIV antigens.
The immunogenic HIV proteins are thought to be
coded by three genes, namely gag, pol and env.
The gag gene codes a precursor p53/55,
which is then cleaved to p24/25 and p17/18. The pol gene codes for p31/32, and the env
gene codes the precursor protein p160 which is cleaved to p120 and p41/p45. (1)
The
p120 protein.
The
generally accepted view is that p120 and p41 are cleavage products of p160, which is found
only in infected cells and not in the virus. However, p120 is a component only of the
knobs (spikes) on the surface of HIV particles; The knobs are found only in the budding
(immature) particles; and not in cell free (mature) particles; immature particles are
"very rarely observed".(2)
Despite
these findings, when "purified HIV" is tested against AIDS sera, strong bands
corresponding to p120 and p160 develop. The solution to these contradictions was found
when it was shown that p80 (vide infra) and "the components visualized in the
120-160-kDa region do not correspond to gp120 or its precursor but rather represent
oligomers of gp41".(3)
The
p41 protein.
p41
is one of the proteins detected by both Gallo's and Montagnier's groups in the first HIV
isolates.
However, Montagnier and his colleagues observed that AIDS sera reacted with a
p41 protein both in HIV and HTLV-I infected as well as non-infected cells, and concluded
that the p41 band "may be due to contamination of the virus by cellular actin which
was present in immunoprecipitates of all the cell extracts".(4)
Although Gallo's
group did not find such reaction with p41 in non-infected cells, they did find a p80
protein and concluded that the reaction was "non-specific"(5).
Actin
is an ubiquitous protein which is found in all cells as well as bacteria and several
viruses.
Well known retroviruses such as the mouse mammary tumour virus and Rous sarcoma
virus have also been shown to contain actin of cellular origin and it has been postulated
that this protein plays a key role in both retroviral assembly and budding.(6,7) It is
also known that oxidation of cellular sulphydryl groups, as is the case in AIDS patients
(8), is correlated with assembly of polymerised actin (9), and that the level of actin
antibody binding to cells is determined by the physiological state of the
cells. For this
reason actin antibody binding to cells has been proposed "as a sensitive marker for
activated lymphocytes"(10).
Platelets
from healthy individuals also contain a p41/45 protein which reacts with sera from
homosexual men with AIDS and immune thrombocytopenic purpura (ITP) and which
"represents non-specific binding of IgG to actin in the platelet
preparation"(11).
The
p32 protein.
In
1987 Henderson isolated the p30-32 and p34-36 of "HIV purified by double
banding" in sucrose density gradients. By comparing the amino-acid sequences of these
proteins with Class II histocompatability DR proteins, they concluded that "the DR
alpha and beta chains appeared to be identical to the p34-36 and p30-32 proteins
respectively"(12).
The
p24/25 protein.
Detection
of p24 is currently believed to be synonymous with HIV isolation and
viraemia. However,
Apart from a joint publication with Montagnier where they claim that the HIV p24 is
unique, Gallo and his colleagues have repeatedly stated that the p24s of HTLV-I and HIV
immunologically cross-react (13);
Genesca
et al.(14) conducted WB assays in 100 ELISA negative samples of healthy blood
donors; 20
were found to have HIV bands which did not fulfil the then (1989) criteria used by the
blood banks for a positive WB.
These were considered as indeterminate WB, (WBI), with p24
being the predominant band, (70% of cases).
Among the recipients of WBI
blood, 36% were
WBI 6 months after transfusion, but so were 42% of individuals who received WB-negative
samples. Both donors and recipients of blood remained healthy.
They concluded that WBI
patterns "are exceedingly common in randomly selected donors and recipients and such
patterns do not correlate with the presence of HIV-1 or the transmission of HIV-1",
"most such reactions represent false-positive results";
Antibodies
to p24 have been detected in 1 out of 150 healthy individuals, 13% of randomly selected
otherwise healthy patients with generalised warts, 24% of patients with cutaneous T-cell
lymphoma and prodrome and 41% of patients with multiple sclerosis.(15)
Ninety-seven
percent of sera from homosexuals with ITP and 94% of sera from homosexuals with
lymphandenopathy or AIDS contain an antibody that reacts with a 25Kd membrane antigen
found in platelets from healthy donors and AIDS patients, as well as a 25 Kd antigen found
in green-monkey kidney cells, human skin fibroblasts, and herpes simplex cultured in
monkey kidney cells. This reaction was absent in sera obtained from non-homosexual
patients with ITP or non-immune thrombocytopenic purpura.(11)
Conversely,
the p24 antigen is not found in all HIV positive or even AIDS patients. In one
study, the
polymerase chain reaction (PCR) and p24 were used to detect HIV in patients at various CDC
stages from asymptomatic to AIDS. p24 was detected in 24% patients and HIV RNA in 50%.(16)
In
another study, "In half of the cases in which a subject had a positive p24 test, the
subject later had a negative test without taking any medications that would be expected to
affect p24 antigen levels...the test is clinically erratic and should be interpreted very
cautiously".(17)
The
p17/18 protein.
In
addition to the p24 band, the p17/18 band is the most often detected band in WB of healthy
blood donors.(18)
Sera
from AIDS patients bind to a p18 protein in mitogenically stimulated HIV infected
T-cells,
but not to non-infected, unstimulated lymphocytes. However, when the lymphocytes are
mitogenically stimulated, but non-infected, the AIDS sera bind to a p18 protein in these
non-infected lymphocytes.(19)
A
monoclonal antibody (MCA) to HIV p18, reacts with dendritic cells in the lymphatic tissues
of a variety of patients with a number of non-AIDS related diseases;(20) and the
"same pattern of reactivity was present in normal tissue taken from uninfected
individuals as in those taken from HIV positive subjects".(21)
AIDS
patients and those at risk have high levels of antibodies to the ubiquitous
protein-myosin,(22) which has two subunits of molecular weights 18,000 and 25,000. In view
of all the above evidence it is difficult to defend the view that the bands p41 (and thus
p160 and p120), p32, p24 or p18 represent specific HIV proteins.
Even if it could be shown
that all these proteins are HIV specific, it cannot be automatically assumed that
antibodies that react with each of these proteins are specific to HIV
infection.
Standarisation
of HIV Antibody Tests
An
antibody test becomes meaningful only when it is standardised, that is, when a given test
result has the same meaning in all patients, in all laboratories, in all
countries. From
the first antigen-antibody reactions performed by Montagnier's (4) and
Gallo's (23) groups (fig.1, 2) it was found that: not all of the "HIV proteins" react with all sera
from AIDS patients or even sera from the same patients obtained at different
times; and
that sera from AIDS patients may react with proteins other than those considered to be HIV
antigens. Because of these variable reactions, an essential requirement was to establish
criteria as to what constitutes a positive WB.
Initially, Montagnier's group considered p24 sufficient to define a positive WB, whereas
Gallo's
group considered p41 sufficient. Most, if not all other laboratories, used the criteria
recommended by the CDC, namely the presence of a band at either p24 or p41. By 1987 it
became obvious that those bands were not HIV specific.
Furthermore, till 1987 "there
were as many WB procedures as there were laboratories doing the assay".(24)
Since
then, all major laboratories have changed their criteria for WB interpretation but in the
United States there are still no nationally agreed criteria, even among the major
laboratories:
In
1987 the Food and Drug Administration (FDA) licensed a WB kit manufactured by
DuPont. The
DuPont kit remains the only licensed WB kit and is used by a minority of
laboratories. It
specifies "extremely stringent" criteria for a positive result namely
"specific bands representing three different gene products: p24 (gag), p31
(pol), and
an env band, either gp41, gp120 or gp160" (24).
The
American Red Cross defines a positive result as presence of antibodies to at least one
gene product from each of the gag, pol and env genes, without specifying which
bands.
The
Association of State and Territorial Public Health Laboratory Directors/Department of
Defence/CDC consider a WB positive if two out of p24, gp41 and gp120/160 are
reactive.
The
Consortium for Retrovirus Serology Standardization (CRSS) defines a positive WB as the
presence of antibodies to at least p24 or p31/32, and gp41 or gp120/160 (25).
All
the other major USA laboratories for HIV testing have their own criteria. For all
laboratories, a negative result requires the absence of any and all bands including bands
which do not represent "HIV proteins".
All other patterns which do not satisfy a
given laboratory's criteria for a positive or negative test are regarded as WBI by that
laboratory.
Thus,
in the scientific literature, no strips have been published of a standard positive WB.
Fig.0 is reproduced from the instruction manual of a WB kit
manufacturer, Bio-Rad.
Although given as "Examples of a typical reactive patient serum sample and reaction
with a strong, weak and non-reactive control" it is also stated, "This example
shows typical reactive patterns only, and is not to be used as a reference for comparisons
with results from unknown serum samples...Patient samples may show varying degrees of
reactivity with different proteins, thus showing different band development
patterns...Each laboratory performing Western Blot testing should develop its own criteria
for band interpretation. Alternatively, band interpretation may be left to the
clinician".
In
addition to the obvious problems associated with the lack of standardisation, all of the
above interpretations possess major problems:
When
the FDA criteria are used to interpret the WB, only a minimal number (less than 50%) of
AIDS patients have a positive WB, that is, are infected with HIV. If the criteria of the
CRSS are used, the percentage of AIDS patients testing positive increases to 79%.
More importantly, even when the most stringent criteria are used, 10% of control
samples, which
include "specimens from blood donor centers", have a positive WB (25).
As
already mentioned, Henderson and his colleagues have shown that p31/32 is a non-HIV
protein.
Pinter and his colleagues have shown that p160 and p120 are oligomers of gp41.
They have also shown that the WB pattern obtained is dependent on many factors including
temperature and the concentration of sodium dodecyl sulphate used to disrupt the
"pure virus", and concluded:
"Confusion
over the identification of these bands has resulted in incorrect conclusions in
experimental studies. Similarly, some clinical specimens may have been identified
erroneously as seropositive, on the assumption that these bands reflected specific
reactivity against two distinct viral components and fulfilled a criterion for true or
probable positivity. The correct identification of these bands will affect the standards
to be established for Western Blot positivity: it may necessitate the reinterpretation of
published results"(26).
The
finding that the p31/32 band represents a cellular protein, and that p120 and p160 are
oligomers of p41, reduces the criteria of the CRSS and that of the American Red Cross to
two bands, p24 and p41, which according to Colonel Donald Burke are "less than
perfectly specific",(27). The above findings reduce the criteria of the Association
of State and Territory Public Health Laboratory Directors/Department of
Defence/CDC to p24
or p41, generally accepted as being non-specific.
Despite
the above evidence, even at present, the p160, p120 and the p41 bands are considered to
represent distinct viral envelope glycoproteins. In fact, the current WHO guidelines
consider a serum positive for HIV-1 antibodies if "two envelope glycoprotein bands
(with or without) other viral specific bands are present on the strip"(28).
To
date, AIDS in Africa is defined on clinical grounds. Recently, the CDC recommended the
future inclusion of serological evidence for HIV infection in the African definition of
AIDS. The test recommended is ELISA, (29) which cannot be considered
specific.
In
Russia, in 1990, out of 20,000 positive screening tests "only 112 were
confirmed" using the WB as a gold standard. In 1991, of approximately 30,000 positive
screening tests, only 66 were confirmed (30).
In
the Latin American and Caribbean AIDS definitions the "clinical findings of HIV
infection" are confirmed "by antibody testing using ELISA, immunofluoresence or
Western blot methods". No criteria are given for WB interpretation (31).
Reproducibility
The
problems associated with reproducibility may be best illustrated by two
examples. Fig.3
represents WB strips of a serum specimen from a patient with AIDS, tested by 19
laboratories that participated in the second CRSS conference on WB test standardisation
(25). As can be seen, the band pattern obtained with one and the same serum, varies from
laboratory to laboratory, although all laboratories reported this specimen as positive.
The
Transfusion Safety Study (TSS) Group in the USA submitted approximately 100 patient
samples weekly for WB testing to three reference laboratories over three separate periods
of several months. With the 100 patient samples, they submitted aliquots from four quality
control (QC) plasmas, two positive and two negative.
HIV positivity or negativity
"was based on the collective experience with each plasma using: (a) licensed EIA
systems of five manufacturers, (b) an immunofluoresence assay, (c) IB in four reference
laboratories, and (d) a radioimmunopreciptation assay in an additional laboratory".
(EIA=ELISA;IB=WB).
The
samples were then sent to reference laboratories which were aware of quality control
testing, but "the labels and codes did not permit identification of the QC specimens
as such or linkage to previous QC specimens".
QC1#(+)
was submitted 40 times to laboratory A, 5 times to laboratory B and 45 times to laboratory
C.
A reported the following band patterns: p24, p32 and gp41/120, 7 times; p24, gp41/120,
28 times; p24 only, 5 times. B reported: p24, p32, gp41/120, 4 times; p32, gp41/120, on
one occasion. C reported: p24, p32, gp41/120, 26 times; p24, gp41/120, 10
times; p24, p32, twice; p24 only, 5 times; "others", once; no
bands, once.
QC#2(+)
was sent a total of 89 times to the three laboratories and was reported: p24, p32,
gp41/120, 64 times; p24, gp41/120, 19 times; p24, p32, once; p32, p41/gp120, 4
times; no bands, once.
A
total of 101 aliquots of the two quality control negative samples QC#3(-) and
QC#4(-) were
sent to the three laboratories. These were reported: no bands, 67 times; "other"
bands, 13 times; gp41 only, once; p24 only, 18 times; p24,p32,gp41/120,
twice.
A
special panel of QC samples was sent to laboratories B, C and an additional laboratory D.
The panel consisted of three aliquots of each of eight samples, including batches
QC#1(+), QC#2(+), QC#3(-) and QC#4(-).
Discussing
the latter results the authors state: "Only Laboratory C's reports with the panel
were consistent with the data accrued from all other evaluation of
reactivity...
Laboratory B reported the three aliquots of QC#1 (+) as respectively positive on the basis
of three bands (gp41, p55 and p65),indeterminate on the basis of a single band (gp41), and
negative (no bands observed). In addition, all three aliquots of QC#6(-)were considered
indeterminate because only a single band (gp41) was seen. Laboratory D reported one
aliquot of QC#6(-) as positive (p15, p24, p32, gp41, p65) and the other two aliquots as
negative (no bands observed). It also reported a band at p55 for all three aliquots of
QC#3(-)".(32)
In
considering the results detailed above, one must bear in mind that they occurred in
Reference Laboratories, that is, first class laboratories which constitute only a small
number of the total number of laboratories which perform WB testing in the USA.
In addition, many laboratories continue to use unlicensed WB kits because of cost and the
"stringent criteria required for interpreting the licensed test".(33)
Specificity
of the HIV Antibody Tests
The
task of authenticating a new diagnostic test in clinical medicine requires an alternative
independent method of establishing the presence of the condition for which the test is to
be employed. This method, often referred to as the gold standard, is a crucial sine qua
non, and represents the tenet upon which rests the scientific proof of
validity.
The
only possible gold standard for the HIV antibody tests is the Human Immunodeficiency Virus
itself. Obviously, the clinical syndrome and the decrease in T4 cells cannot be considered
a gold standard.
Although HIV has never been used as a gold standard there is general
consensus that proof of the specificity of the HIV antibody tests is firmly
established.
For the ELISA, Gallo's best figures, obtained from AIDS patients and 297 healthy blood
donors, were 97.7% sensitivity and 92.6% specificity assuming borderline tests as
positive, and using the clinical syndrome as gold standard.(34)
Colonel
Donald Burke and his colleagues from the Walter Reed Army Institute in the USA are
credited as having most thoroughly researched the problem of defining HIV antibody
specificity in a large population and his data is widely believed to represent the current
state of the art.(35)
Burke
et al (36) tested a highly selected healthy subpopulation of 135,187 individuals chosen
for a very low prevalence of HIV infection--1/10th that of a much larger pool of
applicants (1.2 million), for US military service.
All
applicants were screened with an initial ELISA. All reactive ELISA tests were repeated in
duplicate. Then an initial WB was performed and, if diagnostic or reactive, a second WB
was performed on another fresh blood specimen. Initially the criteria for a positive and
diagnostic WB were the "presence of a band at 41kd, a combination of the bands 24 and
55kd, or both.
Beginning
in May 1987, the method of preparing blot strips was modified so that antibodies to gp120
and gp160 could be detected reproducibly, and criteria for a reactive and diagnostic blot
pattern were changed to those of the Association of State and Territorial Public Health
Laboratory Directors".
A
positive WB was diagnosed if and only if the first and second serum samples were
diagnostic on WB.
All of the diagnostic WB samples were then assayed with four other
antibody tests. A WB was considered "true positive if all four assays on all
available serum samples from an applicant were reactive and diagnostic", but was
considered "false positive if all four assays on all available serum samples from an
applicant were non-reactive, non-diagnostic or both".
From
the 135,187 applicants, there were 16 positive tests. In one of these, the serum was
unavailable for further testing and one applicant declined to provide a second
sample.
Serum from 27 of the 29 samples from the 15 applicants found positive were tested by the
four other antibody tests. Fourteen samples were found positive by all four assays and all
four were negative for one applicant.
From
this Burke and his associates calculated the false positive rate as 1 in 135,187 or
0.0007%.
They also speculated on the implications that this data might hold for their
entire population of 1.2 million applicants. They calculated the overall prevalence of
1.48 per 1000 in the entire pool as equivalent to 200 per 135,187. Assuming that the false
positive rate is the same for the whole population they estimated that since there will be
200 true positive tests per 135,187 persons of which only one will be a false positive
then the "predictive value of a positive diagnosis in the program is 99.5%, and a
specificity of 99.9%".(35,36)
Much
of Burke's and his colleagues' reasoning is open to criticism:
(I)
There is no gold standard for defining HIV infection. Testing the positive WB in the 15
remaining applicants against four other antibody tests does not enable an independent
establishment of "true" HIV infection as they are the same test;
(II)
They define: (a) the true positive tests as samples which repeatedly test positive in four
similar tests.
(b) the false positive tests as samples which repeatedly test negative in
four similar tests.
The number of samples tested and the repeats is arbitrarily
defined.
It would be impossible to say what the outcome would be if for example the ELISA tests
were repeated three instead of two times or if the samples which tested negative in the
first ELISA were tested again with another ELISA or WB. There are well documented reports
in which the ELISA is negative and the WB positive.(37) (c ) the false positive rate as
the number of false positive results divided by the number of samples tested. These
definitions bear no resemblance whatsoever to those described in standard
texts.(38)
The correct definitions are:- (i) A true positive is a positive test occurring in an
individual who is HIV infected as defined by an independent gold standard; (ii) A false
positive is a positive test which occurs in an individual who, by application of the gold
standard, does not have HIV infection, (but is not necessarily healthy); (iii)
The false
positive rate is the number of false positive tests as a fraction of all positive
tests,
both true and false positive.
(III)
The Burke et al premises are quite the opposite to those of Gallo et al where all positive
test results in healthy individuals are regarded as false positive. Based on Gallo and his
associates' premises we must regard all sixteen cases as false positives as there is no
compelling reason for regarding healthy military applicants as significantly different
from healthy blood donors.
(IV) Burke's extrapolation to the entire 1.2 million applicants is
invalid. This extrapolation
can only be done if the 135,187 applicants were randomly selected from the entire pool,
which they were not. In the rest of the population the false positive rate may have been
much higher for example as a result of higher concentrations of globulins in general or of
autoantibodies in particular.
Their
stated figure of 99.5% positive predictor value is impossible to arrive at without
knowledge of the sensitivity of the WB test and the prevalence of true HIV
infection, (38)
even if the specificity and the extrapolation were correct.
(V)
It is impossible to define specificity, sensitivity and predictive value with the
algorithm used by Burke and his associates. The best they can do with their algorithm is
to determine the reproducibility of ELISA and WB.
In this regard, in Burke's larger study
of 1.2 million healthy military applicants, approximately 1% of all initial, 50% of all
repeat ELISAs were positive; and 30-40% of first WB were positive and 96% of second WB
were positive.
In other words Burke's larger study reveals: (a) 6,000 individuals with an
initially positive but subsequently negative ELISA. (b) 4,000 individuals with two
positive ELISA's followed by a negative WB. (c ) 80 individuals with two positive
ELISA's,
an initially positive WB and a negative repeat WB.
This
cannot be regarded as a trivial problem since: (I) both ELISA and WB are regarded as
highly sensitive and specific.(24) (II) Several thousand healthy individuals have
antibodies that react with "HIV proteins" but who are ultimately deemed not to
be HIV infected; (III) Even in the best laboratories, 80 of Burke's healthy applicants
would be diagnosed as HIV infected since, unlike Burke, only one WB is
performed.
The
problem becomes even more serious when one realises that by September 1987 by which time,
based on the antibody tests, a causal relationship between HIV and AIDS was generally
accepted, a single positive ELISA or a positive WB, one band (either p24 or p41) was
sufficient to confirm HIV infection.
At present, the general opinion is that the ELISA tests have a "sensitivity and
specificity of over 98%, many approaching 100%",(24) and the CDC AIDS definition
"accepts a reactive screening test for HIV antibody without a confirmation by a
supplemental test because a repeatedly reactive screening test result, in combination with
an indicator disease, is highly indicative of true HIV disease".(39) (screening
test=ELISA).
Burke
et al, like Gallo et al, determined specificity without reference to sick
individuals. The
definition of specificity requires that the test is evaluated in persons who do not have
the disease which is under scrutiny, including sick individuals who have other diseases
where antibodies, some of which may interact with HIV antigens, may be produced for other
reasons. The specificity of the HIV antibody tests must be determined by testing
individuals who are immunosuppressed and/or who have symptoms and clinical signs similar
to AIDS, but who are not considered to have AIDS or HIV infection. This point is well
illustrated by the serological tests for syphilis.
A healthy person who is not infected
with Treponema pallidum would very seldom test positive (false positive).
However
several authors attest to the presence in various unrelated disorders of biological false
positive tests to syphilis (BFPS), which may occur in patients with auto-immune haemolytic
anaemia, systemic lupus erythematosus (SLE), idiopathic thrombocytopenic
purpura, leprosy
and in drug addicts.
More than 20% of drug addicts test positive and have the highest
incidence of BFPS's.(40)
Persons with BFPS were also found "to
have a high frequency of other serological abnormalities including anti-nuclear
factors, autoantibodies, and alterations of gamma globulin". This led researchers to conclude
that "a BFP reaction often is a marker for an unidentified disorder of the immune
system that predisposes to autoimmune diseases".(40) It is of significance that a
high proportion (14%) of AIDS patients were also found to have false positive syphilis
serology.(41)
At
least two groups of researchers raised the possibility that the HIV antibody test in
Africans and IV users may also be a BFP reaction. Jaffe et al (42) tested 1129 serum
samples from IV drug users and 89 controls from non-users. All samples were collected
during 1971-1972 and tested by two commercial ELISAs and WB.
Seventeen of the samples from
the IV drug users, but not one of the controls was found positive.
They concluded: "On the basis of our positive Western Blot data, it appears that
parenteral drug users may have been exposed to HTLV-III or a related virus as early as
1971. An alternative but equally viable explanation is that the HTLV-III seropositivity
detected in these specimens represents false positive or non-specific reactions".
Biggar
and his colleagues (43) found that in healthy Africans the probability of finding a
positive HIV antibody test increased significantly with increasing immune-complex
levels.
They concluded "reactivity in both ELISA and Western Blot analysis may be
non-specific in Africans....the cause of the non-specificity needs to be clarified in
order to determine how they might affect the seroepidemiology of retroviruses in areas
other than Africa, such as the Caribbean and Japan".
That
a positive WB in all individuals may represent a BFP reaction is suggested by evidence
from both retrovirology in general and HIV antibody testing in particular.
It
is known that all antibodies including MCA are polyspecific and are capable of reacting
with immunising antigens as well as other self and non-self components.(44,45) In relation
to retroviruses, the scientific literature abounds with data which convincingly show the
widespread presence of non-specific interaction between retroviral antigens and unrelated
antibodies. Much of this work has appeared as a result of the search for a viral origin
for animal and human neoplasms.(46-50)
In
1975 Gallo discovered that patients with leukaemia have widespread infection
(antibodies)
to a retrovirus which Gallo claimed to have isolated from cultures and fresh tissues of
these patients and which he named HL23V.
Gallo suggested that this virus was
aetiologically associated with the disease but HL23V was later shown to be a
"cocktail" of two monkey viruses.
In
1980 Gallo discovered HTLV-I which he and his associates claim causes adult T-cell
leukaemia.
Up to 25% of AIDS patients have antibodies to this virus, (51) however AIDS
patients do not develop leukaemia any more often than the general population. This can
only be interpreted as either HTLV-I does not cause adult T-cell leukaemia or some
retroviral antibodies detected in AIDS patients are non-specific.
In
1986 Essex obtained serological evidence for, and isolated, another "human
retrovirus", HTLV-IV.
Essex's HTLV-IV was later shown to be a monkey virus, now
called Simian Immunodeficiency Virus.
That
a positive WB may not represent proof of HIV infection but is only a non-specific marker
for AIDS, is suggested by the following data:
In
drug addicts there is a strong association between high serum globulin levels and a
positive HIV antibody test and this was the "only variable which remained significant
in a logistic regression model"; (52) In children, using WB as a gold standard,
hyperglobulinaemia identified HIV infected children with a specificity of 97%.53 Sixty
three sera obtained from 23 patients before and immediately after immunoglobulin infusion
were tested for HIV antibodies using WB. Of the 63 sera, 52 (83%) were found positive.
"Several samples tested in an HTLV-III p24 radioimmunoassay were also positive. The
amount of antibody detected was greatest immediately after infusion and decreased between
infusions".(54)
An
individual was given six 5ml injections of donated Rh+ serum, administered at 4 day
intervals. "The donor serum was shown to be negative on HIV antibody and antigen
ELISA, so was blood taken from his wife and child".
"Blood taken after the first
immunization was shown to be negative on HIV antibody ELISA and immunoblot
assay. After
the second immunization a weak signal on ELISA, slightly above the cut-off
level, was monitored.
After the third immunization the signal was strong and immunoblot revealed
distinct interaction with p17 and p55 proteins. An even stronger signal was monitored
after the fifth immunization. Interaction with p17, p31, gp41, p55 and some other proteins
was evident".(55)
Since
individuals from the main AIDS risk groups, that is, gay men, drug users and haemophiliacs
are exposed to many foreign substances such as semen, drugs, factor VIII, blood and blood
components; and individuals belonging to the above groups commonly develop infections
unrelated to HIV; one would expect these individuals to have high levels of antibodies
directed against antigens other than HIV. In fact at present, evidence exists that
individuals with AIDS, AIDS-related complex (ARC) and those at risk, have circulating
immune complexes, rheumatoid factor, anti-cardiolipin, anti-nuclear factor,
anti-cellular, anti-platelet, anti-red cell, anti-actin, anti-DNA,
anti-tubulin, anti-thyroglobulin, anti-albumin, anti-myosin, anti-trinitrophenyl and anti-thymosin
antibodies.(22,56)
Anti-lymphocyte
auto-antibodies have been found in 87% of HIV+ patients, and their levels correlate with
clinical status.(57,58) Unlike normal sera, 37% of HIV+ sera were found positive for
Type-D retroviruses, (59) whereas HIV is thought to be a Lentivirus.
It
is also known that serum IgG levels are higher in Black blood donors than in
Caucasians;
(60) that some risk groups, drug users and gay men are exposed to high levels of mitogenic
agents, semen and nitrites, (61,62) and that animals treated with such agents develop
antibodies which react with retroviral antigens.(63)
That
the positive HIV antibody test may be the result of antigenic stimulation, other than HIV,
is further supported by the following data:
(I).
HIV is thought to be transmitted by infected needles, yet a higher percentage of
prostitutes who use oral drugs (84%), than IV (46%), test positive; (64)
(II)
"Mice of the autoimmune strains MRL-lpr/lpr and MRL-+/+ made antibodies against
gp120".
Mice that have been exposed to T-lymphocytes from another murine strain were
shown to make antibodies against gp120 and p24 of HIV.(65)
(III)
Recipients of negative blood seroconvert and develop AIDS while the donors remain healthy
and seronegative.(66)
(IV)
In healthy individuals, partners of HIV positive individuals, organ transplant recipients
and patients with SLE, a positive WB may revert to negative when exposure to
semen,
immunosuppressive therapy or clinical improvement occurs; (67,68,69)
(V)
While the frequency of positive HIV antibody tests in healthy blood donors and military
applicants is low, patients with tuberculosis (TB), including those with TB localised to
the lungs, both in the USA70 and Africa, (71) have high frequency, up to 50%, of positive
WBs. In the USA72 (26 hospitals studied), patients who are not at risk of developing AIDS,
and who do not have any infectious diseases, have a high rate of positive WB, (1.3% to
7.8%).
The
above data may be interpreted either as proof that HIV is spreading to the heterosexual
population or that the HIV antibody tests are non-specific. That the latter is the case is
suggested by the fact that by 1988, in the USA, (73) only approximately 66 white males
were reported to have had "heterosexually acquired AIDS".
By 1992 in New York
only 11 men were reported to have AIDS due to heterosexual infection.(74)
Rodriguez
and his colleagues (75) found that Amazonian Indians who have no contact with individuals
outside their tribes and have no AIDS have a 3.3-13.3% HIV WB seropositivity rate
depending on the tribe studied.
In
another study (76) they found that 25%-41% of Venezuelan malaria patients had a positive
WB, but no AIDS. The above data means either that HIV is not causing AIDS "even in
the presence of the severe immunoregulatory disturbances characteristic of acute
malaria", as Rodriguez et al concluded, or the HIV antibody tests are
non-specific.
The
problems associated with the specificity of the WB could be avoided by use of the only
suitable gold standard, HIV isolation. To date this has not been done and based on the
problems associated with HIV isolation, it may never be feasible.
HIV
Isolation
It
goes without saying that virus isolation can be used as a gold standard only if it
provides conclusive genetic, virological and molecular evidence for the existence of a
unique virus. For retroviruses, as a first step towards this goal one must find particles
with morphological characteristics similar to other retroviruses, and demonstrate that
these particles have a unique set of structural components including RNA and proteins
which belong only to these particles and to no other entity.
Peyton
Rous (77) is credited with the discovery and isolation of the first
retrovirus. In 1911 he
was able to repeatedly induce tumours in a particular breed of chickens by means of tumour
derived, cell free filtrates.
Rous
contemplated that either a "minute parasitic organism" or "a chemical
stimulant" might form the basis of his observations; nevertheless, the tumour
inducing filtrates became known as "filterable viruses" or
oncoviruses.
In
the 1950s, in animal cultures and in fresh tissue, especially tumour tissue, particles
later attributed to retroviruses were readily detectable with electron-microscopy
(EM).
In
1970, the enzyme reverse transcriptase (RT) which transcribes RNA into DNA, was discovered
in oncoviruses. Because of this, in the 1970's, oncoviruses became known as
retroviruses.
In
the preceding decade, density gradient centrifugation was introduced to separate and
isolate sub-cellular particles including viruses.
Because
some cellular constituents were found to have the same buoyant density as
viruses, when
viruses were isolated from cell cultures, the best results could be obtained with
supernatant fluids which had high viral concentration, and had low cellular
contaminants.
This
was best satisfied by non-cytopathic viruses and by culture conditions which maintained
maximum cellular viability. Most animal retrovirus (exceptions are the so called animal
immunodeficiency viruses) satisfy the above conditions.
Taking
advantage of the above retroviral properties, by repeated suspension and sedimentation in
sucrose density gradients, one could obtain, at a density of 1.16 gm/ml, a relatively pure
concentration of retroviral particles-that is, obtain retroviral particles, separate from
everything else, and thus isolate them.(78)
Nonetheless,
as many eminent retrovirologists point out, contamination of the viral preparation with
virus-like particles which contain RT, but could be nothing more than "cellular
fragments", microsomes from disrupted cells, "membraneous vesicles which may
enclose other cellular constituents including nucleic acids", especially when
"inadvertent lysis of cells" was induced, could not be avoided.(79,80,81)
Because
of this, to prove that the material which banded at 1.16 gm/ml contained nothing else but
particles with "no apparent differences in physical appearances", and that the
particles were indeed retroviruses, every retrovirus preparation was further analysed
using the following assays: (1) Physical-electron microscopy (EM) for virus
count,
morphology and purity; (2) Biochemical-RT activity, viral and cellular RNA, total
protein,
gel analyses of viral and host proteins and nucleic acids; (3) Biological-infectivity in
vivo and in vitro.(78,82)
Unlike
animal virus cultures where the particle concentration is very high (104-105 infectious
units/ml), in the AIDS cultures/co-cultures the particle concentration is
low, so low that
both Gallo's and Montagnier's group had difficulty in detecting them.
Unlike
most animal retroviruses, HIV is considered to be a cytopathic virus. If this is so, then
cell culture supernatants will contain many cellular constituents. If, as has been
recently proposed, "a single unique mechanism", HIV induced
apoptosis, can
account for T4 cell death, (83) then the supernatant must also contain apoptotic
bodies,
that is, membrane bound cellular fragments which, (like many retroviruses), bud from the
cell surface.
Since
the size and composition (some contain pyknotic chromatin) of the apoptotic bodies vary
widely, (84) one would expect that some of these fragments will also band at 1.16
gm/ml.
It
is significant that the AIDS cultures/co-cultures do not have maximum
viability, and most
if not all claims of "HIV isolation" have been from cellular
lysates.
Furthermore and most importantly, in an extensive search of the AIDS literature no
electron micrographs were found from the material which bands at 1.16 gm/ml; all the
electron micrographs are of particles found in the cell cultures.
Thus
it is impossible to be know whether the material-lipids, proteins and nucleic
acids, which
bands at 1.16 gm/ml, (the "pure HIV particles"), contains any such particles
whatsoever, and if such particles are present, what is their purity.
The
presently available evidence indicates that only about 20% of the proteins which band at
1.16 gm/ml are "HIV proteins", the rest are cellular, including beta-2
microglobulin and HLA-DR proteins (4.4%).(12,85)
Thus,
even if particles are present at 1.16 gm/ml and all the proteins assumed to be HIV are
embodied in the HIV particle, the material which bands at 1.16 gm/ml cannot be considered
"pure HIV".
Conversely,
"Much of the viral protein secreted from HIV-infected cells is
non-particulate, and
the proportion of (for example) p24 in virions is a function of the viral genotype and the
age of the culture. In extreme cases, less than one per cent of the total p24 and gp120
present [in the culture] is in virions".(86) In fact, p24 is released from
"infected cells independently of infectious virus particles" and
RT.(87,88)
It
must be pointed out that the terms in the AIDS literature "HIV", "HIV
isolation", "pure particles", "virus particles",
"virions" and "infectious particles" have a variety of meanings and
include all of the following, but most often without proof of the presence of a
particle:
(a) "RNA wrapped in protein"; (89) (b) material from the cell culture
supernatants which passes through cell tight filters but through which organisms such as
Mycoplasmas may pass; (90) (c ) the pellet obtained by simple ultracentrifugation of the
culture supernatant (91); (d) recently, very often, detection in AIDS cultures of
p24.(92,93)
In
the first report of "HIV isolation", Montagnier's group detected in a
mitogenically stimulated culture derived from lymph node biopsies of gay men with
lymphadenopathy, "a transient", "reverse transcriptase activity".
In mitogenically stimulated umbilical cord lymphocytes cultured with supernatant from the
above cultures, they reported type-C retroviral particles (RVP) in the cultures and RT and
antigens which reacted with pre-AIDS sera in the material which banded at 1.16
gm/ml.4
Gallo's
group did not consider the detection of the above as representing "true
isolation", "...the virus has not been transmitted to a permanently growing cell
line for true isolation and therefore has been difficult to obtain in quantity".(94)
However,
although Gallo's group used a permanent cell line for "HIV isolation", they
reported nothing more than the same phenomena as Montagnier's group.
Nevertheless,
at present, the detection of the above phenomena are considered to represent "true
isolation" and their finding in a similar culture is regarded as proof of
infectivity. However, isolation is defined as separating the virus from everything else
and not detection of some phenomena attributed to the virus (RT, antibody/antigen
reactions [WB]); or similar to it, (particles).
Phenomena
can only be used for viral detection-even then, if and only if, the phenomena have been
identified as being specific for the virus, by using the isolated virus as a gold
standard.
Although
this has not been done, the presently available indirect evidence (that is, evidence that
has been obtained without a gold standard) from both general retrovirology and AIDS
research, indicates that RT, RVP and the antigen/antibody reactions are not specific for
HIV, (or even retroviruses).
The
specificity of the antigen/antibody reactions has already been discussed and will not be
further mentioned.
In any case, this reaction cannot be used as a gold standard for the
WB, since a test cannot be its own gold standard.
Reverse
transcriptase
In
all HIV research, the copying of the template-primer An.dT15 when incubated with the
supernatant or the material which bands at 1.16 gm/ml from the AIDS cultures/co-cultures
is considered proof of HIV RT activity.
In many instances this activity is considered
synonymous with "HIV isolation" and is used to quantify the virus.
However:
(a) The same template-primer is also copied when incubated with material which bands at
1.16 gm/ml from leukaemic T-cell cultures (95) and normal non-infected
spermatozoa.(96)
Both An.dT15 and Cn.dG15 are copied by material which bands at 1.16 gm/ml originating from
normal non-infected but mitogenically stimulated lymphocytes.(95,97) (b) An.dT15 is copied
not only by RT but also by two (beta and gamma) of the three cellular DNA
polymerases. In fact, in 1975, an International Conference on Eukaryotic DNA polymerases defined DNA
polymerase gamma as the cellular enzyme which "copies An.dT15 with high efficiency
but does not copy DNA well".(98) Thus, the copying of the template-primer An.dT15,
cannot be considered synonymous with the presence of HIV RT.
Particle
detection
Retroviruses
are enveloped infectious particles about 100-120nM in diameter with a core comprising a
protein shell and a ribonucleoprotein complex. Retroviruses are classified into three
Subfamilies-Spumavirinae, Lentivirinae and Oncovirinae. Retroviruses belonging to the
latter Subfamily are divided into Type-A, B, C and D particles.
Nevertheless,
some of the best known retrovirologists do not consider the finding of "virus-like
particles morphologically and biochemically resembling", retroviruses, proof of the
existence of such viruses.(99)
In
the 1970s, such particles were frequently observed in human leukaemic
tissues, (99)
cultures of embryonic tissues, (100,101) and "in the majority if not
all, human
placentas".(102) However, they continue to be "an intriguing and important
problem that remains to be solved".(103)
The
particles detected in AIDS cultures/co-cultures are considered by all AIDS researchers as
being HIV. However:
(I)
There is no agreement as to which Genus or even Subfamily of retroviruses they
belong.
Sometimes agreement is not found even within the same group. For example,
Montagnier's
group initially reported HIV as a Type-C oncovirus, (4) then a Type-D oncovirus (104) and
subsequently as belonging to a different Subfamily of
retroviruses-Lentivirinae.(105) Moreover, the "HIV particles" in monocytes differ from both the Type-C
Oncoviruses and Lentiviruses.(106)
(II)
Despite the above, Gelderblom et al put forward an HIV model (fig. 4) which has a well
defined morphology and composition, including surface knobs made of p120, a protein
considered to play a crucial role in cytopathogenesis and to be indispensable for HIV
infectivity.(107) The model has been accepted and is well known.
However, the same group
using EM and immune electron-microscopy has shown that: (a) knobs are found only in
immature (budding) particles. Immature particles are "very rarely observed", and
are seen only "on metabolically impaired cells";(2,108) (b) mature particles are
"hardly, if at all, labelled" by AIDS and ARC sera. Immature particles are
"highly labelled", but so is the rest of the cell from which they are
budding,
which "might be due to the fact that natural immune sera are indeed
polyspecific";(2,109) (c ) like sera, antibodies to p120 react preferentially with
immature particles.(107) MCA against gag proteins label the mature particles, but they
also label HIV-2 particles and simian immunodeficiency virus particles;(110) (d) in the
HIV particles, including its membrane, they (111) as well as others, (112) detected many
cellular proteins, but with the possible exception of the "lateral bodies",
these proteins are not included in the idealised HIV model.
(III)
The T-cell and monocyte "HIV infected cultures" contain in addition to particles
with the morphologies attributed to HIV, many other "viral particles" unlike any
of the "HIV particles". (106,111,113,114) Non-HIV infected H9
cells, from which
most of the published EM have originated as well as other cells used for "HIV
isolation", CEM, C8166, EBV transformed B-cells, and cord blood
lymphocytes, express
budding virus-like particles albeit they are somewhat different from particles accepted as
HIV.(115) The above data raises questions not only in regard to the origin and role of the
"non-HIV particles", but also the "HIV particles", and as to
which, if
any of these particles, band at 1.16 gm/ml.
(IV)
Budding and mature type-C particles appear in metabolically impaired but non-HIV infected
lymphoma cells.(116) "Retroviral particles" antigenically related to HIV have
been found in cultures of salivary gland extracts from patients with
Sjorgen's syndrome.(117)
The
independent finding of "virus-like" particles in the lymph nodes of AIDS
patients with lymphadenopathy (118) and of proteins in the lymph nodes which reacted with
MCA to p55, p24 and p18 (119) were interpreted as proof that the " virus-like
particles" were HIV. However:
(I)
MCA to p18 react with lymphatic tissues of patients who suffer from a number of non-AIDS
related diseases, and also healthy individuals;(20,21)
(II)
As in the AIDS cultures/co-cultures, in the lymph nodes of patients with AIDS and
persistent generalised lymphadenopathy, in addition to the "HIV particles",
particles unlike those of HIV are also found;(120)
(III) Most importantly, in the only EM study
(121), either in vivo or in vitro, in which suitable controls were used and in which
extensive blind examination of controls and test material was performed, virus particles
indistinguishable from HIV were found in a variety of non-HIV associated reactive
lymphadenopathies leading the authors to conclude:
"The presence of such particles do
not, by themselves indicate infection with HIV".
"Il paziente malato di
Aids NON muore a
causa del virus
dell'HIV ma
per alterazioni dell'assorbimento intestinale
e
quindi per ipoalimentazione (malNutrizione),
dovuta a una grave
micosi." (By Dott.
Gerhard Orth, Leuthkirch)