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

1076 Abstracts 60413-60418

12th World AIDS Conference

S60413 Molecular epidemiology of HIV-associated tuberculosis:
A nine-year cohort study in Switzerland
Philippe Sudre1, G. Pfyffer2, T. Bodmer3, S. Bassetti4, E. Bernasconi7,
A. Telenti5, R. Weber6. 1DMI HUG, Rue Micheli-du-Crest, Geneva; 2National
Center for Mycobacteriology, Zurich; 3Institute for Medical Microbiology, Bern;
4 University Hospital Basle; 5 University Hospital Lausanne; 6University Hospital
Zurich; 70spedale Civico, Lugano, Switzerland
Background: Recent acquisition of infection and disease outbreaks contribute
to the increased incidence of tuberculosis (TB) among HIV-infected persons.
DNA fingerprinting of TB isolates was used to identify clusters of patients over a
9-year time period in the Swiss HIV Cohort Study (SHCS) and to determine the
magnitude and risk factors of TB transmission.
Methods: SHCS participants with confirmed TB and available isolates were
eligible for this study. Isolates were typed using the DNA insertion sequence
6110 (IS6110), 36 bp direct repeat, and by IS6110 PCR. Detailed clinical and
epidemiological information was obtained from the SHCS data base and from
retrospective case review.
Results: Out of 7999 SHCS patients, 267 were diagnosed with TB and 137 had
at least one TB isolate available for typing. Of these, 33 (24%) shared 12 different
molecular banding patterns. Cluster size varied between 2 patients (9 clusters)
and 8 (1 cluster). Within a cluster, the time span between the first and the last
TB diagnoses varied between 1 month and 6 years. Out of 12 patients who had
TB twice, two had a re-infection. Definite or possible contact was identified for
21 of 33 cluster patients (64%). Multivariate logistic regression analysis and detailed contact investigation did not reveal any risk marker which was significantly
associated with clustering. There was no evidence of clustering after 1994.
Conclusions: DNA fingerprinting and epidemiological analysis indicates that
over a 9-year period, approximately one quarter of TB cases among HIV-infected
patients in the SHCS were due to recent or ongoing disease transmission. All
TB cluster cases were community acquired. There was no evidence of clustering
after 1994.
60414 Inhibition of HIV-1 by CD8+ cells from seropositive
individuals is antigen processing-dependent
Otto Yang, B. Wilkes, S.A. Kalams, B.D. Walker. AIDS Research Center, Mass.
Gen. Hospital, 149 13th Street, Charlestown, MA, USA
Background: The contributions of cytolytic and noncytolytic mechanisms of HIV-1
suppression by CD8+ cells has been controversial. Recent evidence suggests
that HIV-1-specific cytotoxic T lymphocytes (CTL) may account for both activities.
Methods: A defined in vitro system was developed. First, CTL clones from infected individuals were studied for their ability to inhibit HIV-1 replication in acutely
infected permissive cell lines. Then, non-specifically expanded CD8+ cells from
infected or uninfected individuals were also tested for inhibitory activity. The target cells consisted of T1, H9, or T2 (an antigen processing-deficient derivative of
T1).
Results: HIV-1-specific CTL clones efficiently suppressed viral replication in
a manner which was HLA-restricted and antigen-processing dependent. Bulk
CD8+ cells from seropositive, but not seronegative individuals were efficiently
suppressive only with HLA matched target infected cells. Weak inhibition was
sometimes seen with HLA mismatched target cells and to a far lesser extent with
T2 cells, presumably due to alloreactivity of the effector CD8+ cells.
Conclusions: These data demonstrate that the HIV-1 suppressive effect of
CD8+ cells from infected individuals depends upon infected cell antigen processing, and therefore suggest that HIV-1-specific CTL are likely a functionally
important subset of these cells.
60415 HIV not associated with TB disease from recently
acquired Mycobacterium tuberculosis infection in an
urban community in the northeastern United States
Amanda Durante1, F.L. Merino1, K.A. Harris2, B.N. Kreiswirth2, P.A. Selwyn1.
Yale University AIDS Program, 135 College Street New haven CT 06511;
2Public Health Research Institute, New York, NY, USA
Background: HIV infection increases the risk of developing TB disease upon
recent M. tuberculosis (Mtb) infection. In many cities, AIDS epidemics have been
accompanied by TB epidemics. However, in New Haven, CT, USA (pop. 130,000,
<100 from New York City) the incidence of TB disease has declined since '87,
despite substantial drug use, poverty and a high AIDS incidence (>200 cases
per 100,000 in '93). Directly observed therapy was established for all TB patients
in New Haven in '87, and in '91 CT began a registry to monitor TB prevention
among Mtb/HIV co-infected people. This study aimed to use molecular epidemiology techniques to examine the association between HIV infection and TB from
recent Mtb infection in the New Haven area.
Methods: Data were gathered from routine TB surveillance reports and medical
charts of all TB patients reported to the CT Dept. of Public Health from '92-'96
who were resident or treated in the New Haven area. Restriction fragment length

polymorphism typing was performed on all viable Mtb isolates using currently
accepted methods. Isolates with a non-unique strain were assumed to represent
TB from recently acquired Mtb infection. The association between HIV and TB
from recent Mtb infection, as well as other characteristics, was examined.
Results: 114 TB cases were reported. The majority were male (65%), US born
(68%), and 43% were African-American. A fifth (21/114) were known HIV positive.
63 (55%) had viable M. tuberculosis isolates. Only one quarter (17/63) had a non
unique strain, suggesting primary TB disease. HIV infection was not associated
with non-unique strains (Fisher's Exact = 0.64). Cases with non-unique strains
were more likely to be US born (chi2 = 4.6, p = 0.03) and African American (chi2
= 4.7, p = 0.03)
Conclusions: These data suggest that increasing AIDS incidence does not
necessarily fuel a TB epidemic, even in an urban environment where other TB
risk factors are present. While HIV infection was common among TB patients in
this study, HIV infection was not an independent predictor of a non-unique strain.
These negative findings may reflects the introduction of public health measures
to control TB at a critical time in the AIDS
60416 Comparison between flow cytometric and manual
staining, microscopic counting methods in estimation of
peripheral T-lymphocyte subsets for HIV+ adults
Kai Man Kam1, K.H. Wong2, F.T. Tse3, S.S. Lee2, P.C.K. Li4, W.L. Leung5,
M.Y. Kwok5. 1Rm.802, 8/F, Institute of Pathology, Dept. Of Health, 134 Quee's
Road West; 2AIDS Unit, Dept. Of Health, Yaumati Clinic; 3lnst. of Pathology
Dept. of Health; 4Special Medical Clinic, Qeh; 5Snst. of Pathology, Sai Ying Pun,
China
Objectives: To compare and correlate results obtained by flow cytometry versus
a manual, separation, staining, microscopic counting method in estimation of
peripheral T- lymphocytes subsets amongst HIV-1 infected patients.
Design: Prospective, blinded study.
Methods: Consecutive HIV-1 infected adult patients seen in two centers and
with fresh peripheral venous blood taken were tested simultaneously with a flow
cytometer (FACScount, software v1.0) for CD3+, CD3+/CD4+ (CD4), CD3+/CD8+
(CD8) lymphocytes, CD3+CD4+/CD3+CD8+ ratio (CD4/8) and a manual separation (Ficoll-Hypague) method using myeloperoxidase- safranin incubation mixture,
staining with Ortho monoclonal antibodies (OKT3, OKT4, and OKT8), peroxidase
conjugated anti-mouse IgG (goat) together with an anti-mouse control, and stained
cells were manually counted by microscopy for at least 200 lymphocytes. Samples (8) heavily contaminated with polymorphs despite repeated separations were
excluded. Results (absolute cells/uL) obtained by both methods were correlated
with linear regression.
Results: Seventy- six patient samples yielded analysable results. Testing ranges as cells/uL (flow, manual) were (50-1307, 25-655), (148-2000,
182-2508), (156-3500, 218-4163), (0.05-0.90, 0.09-1.35) for CD4, CD8, CD3+,
CD4/8 ratio respectively. Best-fit linear regression curve showed manual method,
compared with flow cytometry, could overestimate CD4, CD8, CD3+ lymphocyte
counts by 32%, 14%, 15% respectively. CD4 (R = 0.88) appeared better correlated
than CD3+ (0.85), CD8 (0.80), CD4/8 ratio (0.73).
Conclusion: In our hands using peripheral venous blood from HIV-infected
adults, manual method yielded results which can be compared and correlated
with those by flow cytometry. In places where there is limitation in acquiring a
flow cytometer, manual method appeared to be a comparable technique and feasible alternative in enumeration of peripheral lymphocyte subsets for monitoring
HIV-infected adults.
S60417 The contribution of the army department to the fight
against AIDS
Allao Dounia Adriankaye1, M. Tahir Adam2, Y.P. Alexandre3. 1ETAT Major
General Des Armees. TCHAD, Bp. 404, Najamena; 2PNLS TCHAD, Najamena;
3Population and AIDS Control Project, Najamera, Chad
Issue: A hard core of fight against AIDS is created in the department of Army as
a result of a survey conducted in 1995 with a group of soldiers confirming a high
rate of HIV seroprevalence and in the logic of the short term plan of the second
generation this hard core is created to develop in the profit of this vulnerable
group a guenine programm of fight against AIDS.
Project: The project is some what a follow up of cohort with an epidemiological,
educative section and another section of taking care of STD's. What mattered
was the follow up of tendances after a determination of a basic seroprevalence
of the epidemic in this population with the support of educative and taking care
section of STD's. To this, we can add the developpment of specific materials of
sensibilization and the distribution of condoms, etc.
Results: The determination of the basic seroprevalence was realised, the sitting up of effective section of support and the determination of the incidence the
first year are in process.
Lessons Learned: The project is a follow up of cohort. It's too early to draw
conclusion considering the objectives of the projects. Yet with figures, we have
noticed in the logic of educative and preventive measures (use of condoms
and appropriate materials of sensibilization), of early taking care of STD's a
noticeable decline these last years and a great improvement of kwnoledges on
HIV/AIDS/STD (focus survey conducted with the interested individuals).

[60418 The contribution of the welfare and social action
department to fight against AIDS in Chad: A key element
for taking care
Mahamat Haoua Hassane1, M. Hissenine2, Y.P. Alexandre3. 2Department of
Social Action; 3Population and AIDS Control Project, Ndjamena, Chad
Issues: The department of welfare and social action with nine (9) other departments are actively taking part in the fight against AIDS in Chad. The approach