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

1128 Abstracts 60691-60695

12th World AIDS Conference

inantly CXCR4. In some CCR5 A32 heterozygous individuals, an increased
naive/memory cell ratio was observed which might contribute to their reduced
number of CCR5 positive cells.
Conclusion: The reduced susceptibility of PBMC from CCR5 A32 heterozygotes is not due to a reduced surface expression of the co-receptor or an
increased beta-chemokine production. We are currently analyzing whether general host factors exist that determine reduced HIV-1 susceptibility and how these
factors correlate with CCR5 genotype.
60691 The HIV type-1 V3 domain with relation to co-receptor
usage
William Paxton, S. Kang, J. de Jong, J. Goudsmit. Dept. of Human Retrovirology,
AMC, Univ. Amsterdam, Neibergdreef, 15, 1105AZ, Amsterdam, The
Netherlands
We will report on a panel of HIV-1 molecular clones which vary in their envelope
V3 sequence and their ability to utilize different chemokine co-receptors. The 21
viruses used all contain the HXB-1 backbone and vary only in the V3 domain
by 1, 2 or 3 amino acid residues with a wide range in overall charge. The panel
of viruses encompass an array of biological phenotypes with relation to viral
replication and the ability to form syncytia in the SupT1 cell line. We will report
on the ability of these viruses to replicate in U87.CD4 cells expressing variant
chemokine receptors (CCR1, CCR2, CCR3, CCR5 and CXCR4). The sensitivity
of these viruses to a panel of recombinant chemokines will also be presented.
We will discuss the significance of the V3 domain of HIV-1 with relation to viral
evolution both in vitro and in vivo. The results presented will better define the
interaction between the viral envelope and the multitude of co-receptors that can
be utilized by HIV-1.
Conclusions: Co-receptor usage and chemokine sensitivities were studied
for a panel of V3 variant HIV-1 molecular clones which differed in their biologic
properties with relation to viral replication and syncytium formation.
60692 | Phenotypic characteristics of human immunodeficiency
virus type 1 subtype C isolates of Ethiopian AIDS patients
Eva Maria Feny61, A. Bjdrndal1, S. Ayehunie2, A. S6nneborg3. 1Microbiology
and Tumorbiology Center Karolinska Institute 17177 Stockholm, Sweden; 2Dept.
of Biology Addis Ababa University Addis Ababa, Ethiopia; 3Div. Clin. Virol. IMPI
Karolinska Institute, Huddinge, Sweden
Objectives: To study the biological properties of HIV-1 subtype C isolates from
Ethiopian patients with AIDS.
Methods: HIV-1 isolates were obtained from nine Ethiopian AIDS patients.
DNA sequencing of the V3 loop of gp120 envelope protein classified the isolates
as subtype C. The biological phenotype.of the primary isolates was determined
by the use of established CD4+ T-lymphoid and monocytoid cell lines, and coreceptor usage in human glioma (U87) or a human osteosarcoma (GHOST4) cell
line expressing CD4 and either of the receptors CCR2b, CCR3, CCR5, CXCR4,
Bonzo or BOB.
Results: In primary isolation cultures, virus infection was accompanied by
syncytia formation and cell lysis. None of the isolates replicated in T-cell lines,
except the Jurkattat cells. In primary monocyte/macrophage cultures, initial low
level virus replication was followed by a non-productive state, however virus could
be rescued by cocultivation with Jurkattat cells. The isolates were all found to use
CCR5 as the only coreceptor to CD4. Genotype of the V3 region correlated with
the MT-2 negative/NSI phenotype.
Conclusion: The biological phenotype of HIV-1 genetic subtype C appears
to be at variance with the phenotypic characteristics of HIV-1 isolates other
than subtype C. Unexpectedly, all isolates used CCR5 as the only coreceptor to
CD4 and lacked the capacity to establish productive infection in primary monocyte/macrophages. We suggest that in addition to viral phenotype, other factors
may govern the pathogenic potential of these subtype C isolates.
S60693 Making sex work safe: A practical guide for programme
managers, field workers and policy makers
Cheryl Overs1, Paulo Henrique Longo2. 129-35 Farringdon Road London Eli,
UK; 2NSWP Rio de Janeiro RJ, Brazil
Making Sex Work Safe is a 96 page handbook which presents some of the
knowledge and experience gained by projects involved in responding to the
health and safety needs of men, women and transgendered people who buy and
sell sexual services. The book contains over 100 illustrations and examples of
successful educational and development programmes in urban and rural settings
in both developing and industrialised countries. It recommends ways to develop,
implement and evaluate strategies for distributing appropriate materials and information, encouraging effective use of sexual health clinics, minimising crime
and violence and providing effective social and economic support to sex workers.
The book also explores a number of specific issues such as drug use, mobility,

youth prostitution, sex tourism community development, human rights and public
health policy.
The response to HIV and commercial sex is often hampered by lack of accessible information about health, human rights and programme development. Making
Sex Work Safe bridges this gap by providing illustrated, concrete examples of
effective strategies in a plain English for an international audience.

60694 Model of simulation to estimate productivity losses
relative to HIV/AIDS in companies, the example of
Abidjan (C6te d'lvoire)
Laurent Aventin, P. Huard. 1Orstm-Anrs, Labo. Retrovirus, 911, Av. Agropolis,
PB5045 Montpellier; 2C.E.FI., Aix en Provence, France
Objectives: To create a simple model allowing estimation of productivity losses
in companies located in countries with high HIV prevalence. To determine causes
of productivity losses according to HIV morbidity and mortality of employees.
Methods: (1) Qualitative research in 3 industrial companies in Abidjan
(1995-996): food processing, textile and paper box. Interviews with company
doctors, managers and workers. Economic analyse of absenteeism period of employees with AIDS, problems dueto this absenteeism, death or leave of employees
with AIDS, recruitment and training of new ones. (2) Interviews with directors or
personnel managers in 5 ohter industries about dismissal of employees with
AIDS.
Results: We identify 3 periods of productivity loss relative to agents with AIDS.
(1) An employee with AIDS stops regularly working for medical reasons up to
death, to leave or to be dismissed, (2) Time between the end of a contract of
employment and the beginning of a new one as a replacement, (3) Time necessary for a new employee to reach the right level of productivity. The results of
this model vary according to companies social policy (capacities of companies
medical services, cpntribution of employers to employee's medical insurance and
dismissal of employees with AIDS) and the skill level of workers.
Productivity
Scale
Initial
level of
productivity
for an employe L prouct Progressive efficiency
curve of an of a new employee
employee with AIDS learning time
ii \I I (
0 - Death or Recruitment + T
leaving Time
Productivity Scale.
Conclusion: Productivity losses are higher for skilled employees than unskilled,
because (1) medical absenteeism of skilled people causes work disorganisation,
(2) It is more difficult and longer to find skilled people on labour market, (3) Skill
jobs require a longer training time. We note too that dismissal of experienced
workers with AIDS could increase productivity losses (opposite to the wanted
effect).
60695 Probabilistic forecasting of AIDS onset in HIV-infected
children
Desiree Caselli1, A. Maccabruni2, C. Gabiano3, L. Galli4, C. Gobbi5,
C. Berzuini6. Clinica Pediatrica IRCCS Policli Nico-san Matteo Piaz. Golo 12
27100 Pavia; 2Dept. Infect. Diseases IRCCS Pol. S. Matteo, 27100 Pavia;
3lstituto di Discipline Pediatriche, Torino; 4CI. Pediatrica Osp. Mayer, Firenze;
5Unita Statistica Medica Ed Epidemilogia IRCCS San Raffaele, Milano; 6Dept.
Information e Sistemistica-Universitadi, Pavia, Italy
Background: In HIV-infected children two clinical patterns are reported: a rapid
disease (about 15%) and a slow disease with prolonged survival. Hence the ability
to predict the residual time to onset of AIDS in individual HIV-infected children,
based on their accumulated marker history, may help in treatment planning. The
extent to which current prognostic categories based on clinical and immunological parameters (CDC '94) may help in this kind of prediction is not clear. This
motivates our effort to set up a probabilistic system for dynamic AIDS forecasting
in individual children based on recently accrued statistical technology.
Patients and Methods: Recent progress in Bayesian statistical inference and
in the so-called Markov chain Monte Carlo approach to computation allows development of realistic models of marker dynamics and hazard dynamics at an
individual child's level. We have focused on the ability of these models to predict
whether the child will develop AIDS within the next year, based on the child's
past CD4+ observations. Using data concerning 125 infected children followed
in 3 Italian centers (Pavia, Florence and Turin) since 1984, we have compared
various statistical models and approaches in terms of their predictive ability.
Results: Our study confirms the importance of the child's current CD4+ counts
for AIDS forecasting. The prognostically important bit of information, in an infected
child of age t, appears to be his current CD4+ level evaluated with respect to the
estimated CD4+ mean in the population of age t. The slope of the child's past
CD4+ trajectory also appears to be important. On average, out of 10 observed
AIDS onsets, as many as 4 are correctly anticipated by the system less than 1
year earlier with predictive probability >0.4. On a total of 100 times at which the
system issued an alarm, telling that a given child would develop AIDS within the
next year with probability >0.3, the child was actually observed to develop the
event in 45 times.
Conclusion: Sophisticated models of marker and hazard dynamics signifi
cantly increase the ability to provide genuine predictions of AIDS at an individual
child's level, based on the child's past marker history.