Bridging the Gap: Conference Record [Abstract book, International Conference on AIDS (12th: 1998: Geneva, Switzerland)]

12th World AIDS Conference

Abstracts 42111-42114 795

CD4+T-cells was measured in HIV1-exposed, HIV1-negative and HIV1-positive
children.
Methods: 17 peripheral blood samples were obtained in 6 HIV1-positive, 28
samples in 18 HIVl-negative children of HIVl-positive mothers and 50 samples of healthy controls. After washing with PBS (Phophate buffered saline)
to remove free serum immunglobulins and complement, nonspecific binding was blocked with donkey serum. Then anti human IgG-Phycoerythricin,
anti CD4-Fluoresceinisothiocyanat and anti CD3-Peridinium-chlorophyll-protein
A were added. After lysing of erythrocytes followed by another washing step,
the absolute number of CD4+T-cells and percentage of cells with IgG on their
surface were determined by standard flow cytometric methods. HIV1-infection
of HIV1-exposed children was excluded when a minimum of three HIV1-PCR's
were negative, two of which were performed >1 month of age and one which was
performed -3 month of age.
Results: In all healthy controls IgG was detected on the surface of up to 1-3%
of CD4'T-cells only. In 27 of 28 samples of HIV1-negative, exposed children
below 12% of CD4+T-cells were coated with IgG. In 17 of 18 HIV-positive children
the rate of CD4+T-cells with IgG was between 13% and 100%. In one HIV-positive
child, the first sample had less than 13% (10%) CD4+T-cells coated with IgG. In
a second probe IgG was detected on all (100%) CD4+T-cells.
Conclusion: The IgG coating of CD4+T-cells is a sensitive mesure to discriminate between HIV1-positive and HIV1-negative individuals. It's potential use
is the early detection of HIV1 positive newborns of/from HIV1 positive mothers.
Also the precondition of autoimmunpathogenesis of HIV1-infection, the antibody
mediated depletion of CD4+T-cells has been shown by this study.
|42111 Screening of anti p24 monoclonal antibodies and their
use in a sensitive HIV antigen assay on Vidas
Emilio Brignoli, N.P. Piga, G.S. Sibai, A.F. Foussadier, J.M.H. Henry, G.V. Vernet,
M.J. Jolivet. Chemin De L'orme, Biomerieux, 69280 Marcy L'Etoile, France
Objective: To select the best anti p24 monoclonal antibodies (mABs) for solide
phase in an HIV antigen assay developped on Vidas system and to study the
sensitivity and specificity of this assay.
Method: A panel of 6 mABs was selected on the basis of their ability to capture
p24 antigen in a sandwich assay using a polyclonal (rabbit) p24 antibody HRP
conjugate. In the same assay format each of this mAbs was used as neutralizing
reagent versus all others. Their ability to capture p24 antigen of different HIV
sub-types including 0 group and HIV-2 isolates was tested in a pairwise assay.
In this way 3 mAbs were selected as the best combination for coating. The Vidas
HIV p24 II assay was developped and its performances were tested using Vidas
analyser. To determine the specificity, 1000 sera from HIV non infected blood
donors or hospitalized patients were tested. Repetitive false positive samples
were tested in a confirmation assay.
To verify the sensitivity we tested 100 HIV p24 antigen positive samples from
our collection, 12 commercial seroconversion panels from BBI, NABI and BioClinical Partners and 20 HIV supernatant samples representing the different HIV
strains (including Diagnostic Pasteur HIV-1 standard).
Results: The specificity obtained in this population was better than 99.5% in
the first intention and 100% after confirmation. The positive sera were all detected. In the seroconversion panels (several sequential samples from the same
patient) p24 antigen was detected in the same samples than with the commercial
P24 antigen assays. Vidas HIV p24 II detected on average the same dilution
of supernatants sample than Vironostika HIV-1 Antigen from Organon Tecnika.
Sensitivity with Pasteur standard was estimated at 5 pg/ml of p24 antigen.
Conclusion: These results show that Vidas HIV p24 II is a sensitive test for
the detection of p24 antigen with a broad specificity for different sub-types and
is adapted for both routine use and single sample testing. Moreover, this test
has a level of specificity which is comparable to those of other commercialized
techniques.
42112 Total IgE levels in infants born from HIV infected mothers
Maria Jose Miguez-Burbano1, C. Hutto2, G. Scott2, G. Shor-Posner3,
M.A. Fletcher4, M.K. Baum. 15 Island Avenue Apt. 2C, Miami Beach, FL. 33139;
2Pedriatrics Univ. of Miami, Miami; 3Psychiatry Univ. of Miami, Miami; 4 Medicine
Univ. of Miami, Miami FL, USA
Background: Vertical transmission accounts for the majority of AIDS cases in
children worldwide. In developing countries, there is no simple, reliable test for
the early diagnosis of HIV infection in infants that does not require the complex
technology of viral culture or PCR. This study was designed to evaluate the
usefulness of total IgE for the diagnosis of HIV-1 infection in children.
Methods: Total IgE (Microplate Total IgE, Kallestad, MN) and HIV status were
determined in 48 children born to HIV infected mothers. All were tested initially at
1-6 months of age and had at least one subsequent test over a 1 year period. A
total of 81 samples were analyzed.
Results: Our results revealed 29 uninfected and 19 infected infants. Levels
of total IgE determined before 6 months of age in the HIV-1 infected children

(200.57 ~ 40.55 IU/ml) were significantly higher as compared to those of the
uninfected children (48.79 ~ 7.63 IU/ml, p = 0.0001). IgE levels of the infected
children were persistently elevated in subsequent specimens. In contrast, most of
the uninfected children (98%) with elevated IgE levels had significantly reduced
levels after six months (p = 0.05).
Conclusions: Paired Total IgE levels may be useful in the presumptive diagnostic of HIV infection in infants in developing countries.

42113 Rapid assay evaluation for the detection of antibodies
anti-HIV-1/2: Capillus HIV-1/HIV-2
Silvina Fernandez Giuliano1, M.B. Bouzas1, G. Juncos1, I. Zapiola1, C. Mueller1,
A. Miroli2, G.R.M. Muchinik1. 1 Unidad De Virologia Hospital "F.J. Muttiz"
Uspallata 2272, 1282 Buenos Aires; 2Subsecr. Deprevencon Y Asistencia,
Buenos Aires, Argentina
Introduction: The Cambridge Biotech Capillus HIV-1/2 test is a latex agglutination assay that uses two env recombinant proteins from HIV-1 and HIV-2. The
assay is performed on a patented capillary agglutination slide. The results are
visually interpreted.
Objective: Evaluation of a rapid and simple Capillus HIV-1/2 test for antibodies
anti HIV-1 detection in serum, plasma and whole blood.
Methods: From 192 patients (98 ELISA+ WB+, 93 ELISA- and 1 ELISA+
WB-) attending to the laboratory, we tested by Capillus HIV-1/2, 140 serum
samples and in 52 whole blood and plasma. A panel of 20 samples from 11
patients ongoing seroconversion was also included. The results were compared
to those from the testing algorithms: third generation ELISA as initial screening
and repeated reactive samples were tested by WB following positive criteria from
CDC/ASTHL. Samples with a negative or indeterminate result by WB were tested
for HIV p24Ag (HIVAG-1 Monoclonal, Abbott Diagnostics) after immunecomplex
acid dissociation..
Results: The Capillus test showed 100% sensitivity, 98.5% specificity, 99.3%
test efficiency. Thus, for serum samples the positive predictive value was 98.6%
and the negative predictive value 100%. Only one sample showed ELISA+ WBp24Ag- and was considered negative since no changes were seen in a second
sample 2 months later. Results from whole blood and plasma were 100% in
agreement to those from serum. All samples from the seroconversion panel were
detected by Capillus..
Conclusion: To our knowledge this is the first report from South America
and our results are similar to previous report from Africa. Because of the 100%
sensitivity and 98.5 specificity found in our study, we consider it will be of interest
to evaluate this assay with a panel of sera from individuals infected with different
types and groups of HIV..
42114 A comparative study of PCR, p24 antigen and HIV-IgA for
early diagnosis of perinatal HIV infection in Brazilian
infants
Marisa M. Mussi-Pinhata1, D.T. Covas1, M. Ueda2, M.C. Cervi1, R. Kimura2,
G. Duarte1, S. Kashima3. 1 Universidade De Sao Paulo, Ribeirao Preto, SP;
2lnstituto Adolfo Lutz, Ribeiraao Preto, SP; 3Fundacaao Hemocentro De
Ribeiraa, Preto, Ribeir.aao Preto, SP, Brazil
Objectives: To compare PCR (polymerase chain reaction), immune complexdissociated p24 antigen (ICD p24) HIV-lgA antibodies for the diagnosis of HIV
infection in Brazilian infants younger than 6 months of age.
Design: Prospective comparison of laboratory findings of a cohort of infants
perinatally exposed to HIV-1.
Methods: The study included 70 infants followed from birth, 27 infants with
confirmed HIV-infection and 43 infants who seroreverted to HIV. Without previous knowledge of HIV-infection status an HIV-1 Nested-PCR (primer pairs 5'V3,
3'V3 and J5'2KSI, J3'2KSI); an ICD p24 (Du Pont, USA) and an HIV-lgA assay
(Western blot with recombinant antigens after depletion of IgG) were done at 0;
1; 3 ~ 1 and 6 ~ 1 months of age.
Results: With the exception of 1 child whose PCR resulted positive at 1 month,
1 child who tested positive at birth by ICD p24 and 1 child with positive IgA at 0
and 1 month, all the remaining 42 HIV-uninfected infants had negative PCR, ICD
p24 and IgA tests at any age (specificity = 97% for 0-1 month and 100% for older
ages). Once positive, all HIV-infected infants had positive PCR, p24 and IgA tests
at subsequent ages. Among infected infants, the positivity rates were: PCR: 9/22
(42%) at birth; 10/24 (42%) by 1 month; 25/26 (96%) by 3 months; 27/27 (100%)
by 6 months; p24: 9/22 (42%) at birth; 12/24 (50%) by 1 month; 23/27 (86%) by
3 months; 23/27 (86%) by 6 months; IgA: 2/22 (9%) at birth; 7/24 (29%) by 1
month; 13/26 (50%) by 3 months; 14/26 (54%) by 6 months. Most of the results
of PCR and p24 were concordant at different ages. PCR, p24 and IgA positive
predictive values were high only by 3 months and after (96.1%; 95.8% and 92.9%;
respectively). Although PCR and p24 had high negative predictive values by 3
months and after (97.7 and 91.3%), IgA showed lower negative predictive value
by this time (76.4%).
Conclusion: These results show that the identification of HIV-infected and
HIV-uninfected infants is better accomplished by 3 months or after this age. PCR
and ICD p24 antigen assays are more useful than HIV IgA because IgA does
not have the sensitivity necessary to be used as an indicator of HIV infection in
infants. Although PCR is more accurate than p24, ICD p24 may be used when
facilities for performing PCR are limited.
S42115 1 HIV-1 reverse transcriptase inhibition associated
antibodies that related to disease progression of HIV-1

infection
Fumitomo Odawaral, K. Sano2, H. Misaki1, M.H. Lee3, K. Detels4. U.S. Macs
Group; 1Mifuku 632-1 Tagatagun, Asahi Chemical Industry Co., Ltd.,
Shizuokaken; 20saka Medical College, Takatsuki, Japan; 3Harbor-UCLA
Medical Center; 4School of Public Health UCLA, California, US
Objective: We attempted to determine the clinical significance of recently identi