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

796 Abstracts 42116-42119

12th World AIDS Conference

fled antibodies that inhibit the HIV-1 RT-nucleic acid complex formation (BI) and
the catalytic activity of the complex (PI).
Methods: The sample participating in this study were recruited for the Multicenter AIDS Cohort Study between 1984-1990. The subjects were grouped to
two categories; non-rapid progressors (non-RP) and rapid progressors (RPs).
Serum samples were collected at each stage of the infection, partially purified
and examined for BI and PI antibody as previously reported (J. Immunol. Methods
199:175-184, 1996).
Results: In the non-RP group, BI antibody was detected in 3.6% of individuals at prior to seroconversion, 50% at seroconversion, 96.4% of subjects with
preAIDS and 78.6% of those with AIDS. The positivities for the antibody in the
RP group were 0%, 25% and 37.5% at prior to seroconversion, at seroconversion
and of subjects with preAIDS, respectively. On the other hand, PI antibody was
found in 42.9%, 82.1%, and 96.4% of subjects in the non-RP group, and 37.5%,
50.0% and 75% in the RP group, at the respective stages.
Conclusions: 1. The positivity for BI antibody was related to the disease
progression of HIV-1 infection and this antibody could be a prognostic marker for
disease progression. 2. The positivity for PI antibody was extremely high at the
prior to seroconversion and this antibody might therefore a sensitive diagnostic
marker of HIV-1 infection.
42116 HIV-2 and non-B subtypes of HIV-1 group M in specimens
submitted to the New York City (NYC) Dept. of Health
Retrovirology Lab. from 1993-1997
Sara T. Beatrice1, W.R. Oleszko2, A. Punsalang2, M.A. Chiasson2, L.V. Torian2,
C.A. Schable3, I.B. Weisfuse2. 1Labs NYCDOH - 2New York City Department of
Health, 455 1st Avenue New York, NY; 3Centers for Disease Control &
Prevention, Atlanta, GA, USA
Objective: To determine the presence of HIV-2 and non-B subtypes of HIV-1
Group M in individuals born in Africa who submitted specimens for HIV-1 testing
to the NYC DOH Retrovirology Lab between 1993-1997.
Design: Retrospective serosurvey
Methods: In an HIV-1 serosurvey using remnant sera originally drawn for
routine HIV-1 screening, 8,803 specimens were tested for HIV-2. All specimens
showing reactivity consistent with infection with HIV-2 were then screened at the
Centers for Disease Control & Prevention using investigational EIA's for antibodies to 12 V3 loop and 4 gp41 peptides representing HIV-2 and most HIV-1
subtypes. Routine HIV-1 test data were matched to the HIV-2 and HIV-1 subtype
results.
Results: During the period from 1993-1997, 786,229 specimens were routinely
screened for HIV-1 antibody with the Cambridge HIV-1 RECOMBIGEN EIA. A
subpopulation of 8,803 specimens from persons most likely to be infected with
HIV-2 were screened with Sanofi's licensed HIV-2 EIA; the EIA reactives were
then tested using Sanofi's or Cambridge BioTech's investigational HIV-2 Western
blots (WB). A total of 186 repeat EIA and WB HIV-2 reactive specimens were
screened with the investigational peptide assay. HIV-2: Of these 186 specimens,
43 were HIV-2 peptide reactive and confirmed to be HIV-2 positive with the Cambridge HIV-2 WB. Of the 43 specimens, 31 had been reported as HIV-1 positive,
3 as HIV-1 inconclusive and 9 as HIV-1 negative. HIV-1 subtypes: All remaining
143 of the 186 specimens were antibody positive for HIV-1 only -16 had typical
subtype A reactivity, 26 subtype B, 69 subtype C, 2 subtype D, 2 subtype F, and
15 had mixed subtypes; 13 of the 143 were not typable. Confirmation of these
preliminary HIV-1 subtype screening data and determination of the number of
individuals represented by the 186 specimens is underway.
Conclusions: The increased detection of HIV-2 and multiple HIV-1 non-B
subtypes underscores the need for testing assays which can readily and accurately identify and quantitate these viruses. Lack of sensitivity/specificity regarding
current supplemental/molecular tests, coupled with the lack of known efficacy of
antiretroviral drugs make it imperative that proper virus typing of all HIV-1 positives
be implemented, especially in areas with a known non-B or HIV-2 seroprevalence.
Ultimately, counseling/testing focused on outreach to at-risk populations is essential for limiting the spread of virus variants within a community.
42117 The utility of immune-complex-dissociated p24 antigen in
the diagnosis of HIV vertically exposed infants in Belo
Horizonte, Brazil
Jorge Pinto1, A.I. Ruff2, R.S. Prado3, J.B. Souza3, M.L. Silva3, N.A. Halsey2,
D.B. Greco3. 1Rua goitacazares 14/408, Belo horizonte, MG 30190-050; 2Johns
Hopkins School of Public Health, Baltimore MD; 3Federal University of Minas
Gerais, Belo Horizonte MG, Brazil
Objectives: To determine the sensitivity and specificity of Immune-ComplexDissociated p24 Antigen (ICD p24ag) detection in identifying infected vertically
exposed infants before 12 months of age.
Methods: After proper informed consent was obtained from the parents or
guardians, serial blood specimens were collected prospectively from 103 infants
enrolled between August 1994 to December 1996. Of the enrolled infants, those

with their HIV status defined at the time of p24 testing were selected: 28 infected
and 25 uninfected. Infants were considered infected if they were repeatedly
seropositive beyond 18 months of age or developed AIDS-associated symptoms
at any age. Uninfected infants were tested negative for EIA twice within a 3
month interval. The person performing the p24 antigen assay (Coulter") was
blinded to the HIV status of infants. The acid treatment for dissociation of immune
complexes consisted of a 1.5 M glycine hydrochloride solution as described by

Bollinger et al (1992). Concentration of p24 antigen was determined by interpolation of the specimens values from a standard curve generated by the serial
dilution of recombinant p24 antigen. The cutoff was an optical density of 0.120 at
the 450-nm wavelength.
Results: Of the 53 enrolled infants, a total of 55 samples from 28 infected
infants and 75 samples from 25 uninfected infants were tested. In infected infants
<6 months of age, ICD p24ag was detected in 5 out of 8 (sensitivity: 62.5%,
95% Cl: 25.9-89.8) and in those tested between 6 and 12 months, 21 out of
25 were positive (sensitivity: 84.0%, 95% CI: 63.1-94.7). Overall, the assay was
able to identify 23 of 28 infected infants (sensitivity: 82.1%, 95% Cl: 62.4-93.2).
None of the uninfected infants had positive ICD p24ag (specificity: 100%, 95%
CI: 83.4-100.0) and the mean age at serorreversion was 12.1 months (range:
7-18).
Conclusions: In this, Brazilian cohort of HIV-exposed infants ICD p24ag
showed to be a useful diagnostic test in confirming or excluding HIV infection.
The sensitivity increased in the second semester of life, specificity was uniformly
high throughout all ages. The ICD p24ag is rapid and inexpensive and remains
an alternative diagnostic technique in settings where PCR and viral culture are
not available.
42118 Application of novel "detuned" HIV EIA to qualify and
monitor anti-retroviral therapy trials in patients with early
HIV infection
Bhupat D. Rawal, F.M. Hecht, J. Kahn, M.A. Chesney, R.S. Janssen,
M.P. Busch. 1Blood Centers of the Pacific, 270 Masonic AV San Francisco, CA
94118; 2University of California, San Francisco, CA; 3Centers for Disease
Control, Atlanta, GA, USA
Objectives: To identify patients with early (6 mo) HIV infection by anti-HIV "detuned" EIA (DTEIA) for enrollment in anti-retroviral therapy trials and to apply
"quantitative" (QDTEIA) for therapeutic monitoring.
Design: Laboratory detection and quantitation of anti-HIV antibody in presentation and sequential samples from HIV-infected patients.
Methods: We tested 225 recently exposed high risk adults presenting to the
San Francisco Options Project by standard screening and DTEIA protocol. DTEIA
detects anti-HIV antibodies at a post-seroconversion window of 129 ~ 20 days in
a 1:20,000 dilution under "detuned" incubation conditions. For 9 patients sequential plasma samples during treatment were tested by QDTEIA using 1:20, 1:400,
1:1000, 1:5000 and 1:20,000 dilutions.
Results: A total of 48/225 patients were confirmed infected and had nonreactivity in DTEIA indicating "early" HIV infection. While serial samples collected
during therapy remained non-reactive at 1:20,000 dilution in DTEIA, samples
from 9 patients tested by QDTEIA showed a progressive lowering of OD around
21-53 post-treatment days in sample dilutions at 1:20, 1:400 and 1: 1000 but not
at higher dilutions. This decline in the antibody levels reversed when two patients
stopped medication.
Conclusion: DTEIA is a simple and practical screening test for enrolling patients with early HIV infection in anti-retroviral therapeutic trials. Application of
QDTEIA using lower sample dilutions further augments the value of this simple
and economical technic for therapeutic monitoring.
42119 1 The expansion of HIV safe blood supply system and
changes in blood transfusion practices in the wake of
HIV/AIDS epidemic in Myanmar
Myint Zaw, Rai Mra, Hla Htut Lwin, Khin Ohnmar San, Dr. Edward Zan. National
AIDS Program 36, Theinbyu Street, Yangon, Myanmar
Background: The testing of blood donations for HIV antibody started in Myanmar
in 1985. Myanmar is divided into 14 State and Divisions with 46 million people
with more than 700 government hospitals of various sizes and facilities. Marked
changes in the blood supply and control systems have taken place during the ten
years of HIV epidemic. Total blood use in the country, blood transfusion practices,
donor selection and deferral techniques were studied for strategic allocation of
HIV test kits and getting the HIV safe blood supply.
Methods: Government hospitals, major blood banks and three national laboratories were surveyed by trained surveyors using the structured survey forms
developed by the National AIDS Program for 12 months during the period November 1996 to October 1997. Questions regarding total blood use, types of HIV test
kits, testing strategies, blood donor deferral techniques, content of donor education and counseling were asked. Facts and data were compiled and analyzed at
National AIDS Program using microcomputers.
Results: There were a total of 701 government hospitals in Myanmar. The bed
sizes ranges from 16 beds (smallest) to 1500 beds (National Specialty Hospitals).
A total of 200, 000 blood units were used each year. Fifty five percent (55%)
of blood collected was used in the fourteen major cities. Almost all of the blood
donations were voluntary and non remunerated. An average 84% of the blood
given could be screened for HIV. The tests used were Elisa, Dot immunoassays
and Particle agglutination tests with a Sensitivity of 100% or 99.5%. WHO testing

strategy II was used for transfusion screening. The HIV test kits were supplied by
UN agencies and donor countries. There were four main types of donor recruitment and deferral strategies. Donated blood was screened by two Elisa tests at
major hospitals and blood banks, donors were screened clinically and HIV testing
done on donated blood, donors were screened both clinically and HIV testing and
a confidential list of risk-free donors was kept, donors were screened and deferred
only by clinical examination alone in remote isolated hospitals. Annual analysis of