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

264 Abstracts 21126-21130

12th World AIDS Conference

HIV-infection, which might contribute to immune mediated destruction of CD4+ T
cells.
21126 CD4 Thl cells specific for HIV-1 antigens are associated
with long-term non-progression (LT-NP)
Fabrienne Hadida1, A.G. Goubar2, O.B. Bonduelle1, D.C. Costagliola2,
B.A. Autran1. Alt Study Group; 1Lab Immunologie Cellularie Hop. Pitie
Salpetriere 83 Bid Hopital 75013 Paris; 2lnserm SC4, IFR en Sante, Hopital
Saint Antoine, Paris, France
Objective: To examine the CD4 T cell status associated to the long term non
progression with regards to HIV-specific CD4 Thl reactivity.
Method: A cohort ("ALT") of LT-NP was recruited in 1994 on the criteria initially
defined as follows: infection for 8 years, positive or null CD4 T cell slope for the
last 5 years above 600/mm3, no retroviral therapy, compared to controls with
the same duration of infection and CD4 counts between 300 and 400/mm3. The
CD4 T cell proliferation against recall (Tuberculin, Candidin and streptococcal)
and HIV-1 antigens (p24) was studied in relationship to plasma load and cellular
viremia.
Results: Up to now 62 subjects have been studied during the first year with
median CD4 = 672/mm3. 11 individuals (ALT-1) had plasma viral load below 200
log HIV-1 RNA copies/ml (20-170), while others (ALT-2) had plasma viral load
above 200 copies/ml (210-860,000). positive CD4+ T cell proliferative responses
to HIV-1 p24 was observed in 75% ALT-1 and only in 20% ALT-2 (p < 0.01),
while reactivity to the 3 recall antigens was conserved in both groups. All responders against HIV-1 p24 had detectable CD4 T cell reactivity against the 3 recall
antigens. In contrast, among non responders to HIV-1 p24 with in ALT-1, such
responses persisted against this 3 recall antigens though with a lower frequency.
Up to now 51 patients were studied during the 2nd year with median CD4 =
616/mm3, and CD4 counts above 600/mm3 only in 50% of patients. Proportions
of p24-specific CD4 T cell reactivity remain at similar levels. The p24-stimulation
predominantly induced an IFNy production indicating a Thl cell response to HIV
which was also negatively correlated to viral load.
Conclusion: We demonstrate that the lack of CD4 reactivity against HIV is
highly correlated to the viral load, and might be the first defect to appear in
antigen-specific T cell responses with progression.
21127 Long-term non-progressive transition to progressive
HIV-1 Infection: Attenuating sequences
Guowei Fang, B. Weiser, B. Burger, C. Chappey, A. Visosky, L. Townsend,
T. Moran, W. Meyer. Wadsworth Center, NYS Dept of Health, 120 New Scotland
Ave, Albany, NY 12208, USA
Background: Study of long-term non-progressive (LTNP) HIV-1 infection presents
an opportunity to identify the determinants of HIV-1 attenuation and pathogenesis
and is relevant to vaccine design. HIV-1 RNA in plasma represents replicating
virus, and therefore we developed a technique to obtain full-length genomic
clones from plasma HIV-1 RNA in order to analyze the complete viral genome
from such instructive individuals.
Methods: We studied an infected individual who underwent a transition from
LTNP to rapidly progressive infection, a transition which was associated with a
shift from low to high plasma viral load. Using reverse transcription and long
polymerase chain reaction (PCR), we cloned multiple HIV-1 RNA genomes from
this patient's plasma and determined the complete nucleotide sequences.
Results: One hundred clones encompassing the entire HIV-1 genome were
obtained from this individual on each of two occasions, one before and one during
the transition in disease state. Five out of the nine full-length genomic clones
assayed were infectious, demonstrating that the genomes coded for viable virus.
Analysis of complete HIV-1 genomic sequences revealed only one major difference between genomes from the two phases of infection; a change was observed
in the Sp 1 transcription factor binding site and adjacent promoter in the long
terminal repeat, a region playing a key role in the control of viral replication. During
the non-progressive phase, the predominant sequences had a large deletion in
an Sp 1 binding site and adjacent promotor; when the infection became rapidly
progressive, all clones had intact Sp 1 and promoter sequences and were derived
from a minor species present earlier.
This case documents that an individual can undergo a transition from LTNP to
progressive infection. Extensive molecular analyses suggest that during the nonprogressive phase, the Sp 1 enhancer-promoter deletion is likely to have played
a role in decreasing replication, thereby attenuating HIV-1 in this case. Analysis
of entire HIV-1 RNA sequences before and after a major clinical transition may
provide a molecular explanation of pathogenic events.
21128 Evidence of histologic changes in the tonsil during
primary HIV infection
Brian Herndier, K. Lee, M. Weinstein, N. Abbey, J. Kahn. UCSF Box 0874, San
Francisco, 94143 CA, USA

Background: A systematic evaluation of tonsillar lymphoid tissue in primary retroviral infection. Morphology, peripheral viral load, in situ studies measuring p24
HIV protein, and HIV RNA ultimately will be correlated in this well characterized
cohort.
Methods: Patients were recruited through the Options Project at San Francisco
General Hospital. Bilateral tonsillar biopsies were taken before the adminsitration

of anti-retroviral therapy. Standard paraffin embedded, hematoxilin and eosin
stained sections were examined by light microscopy. In situ hybridization (ISH)
studies used dioxygenin-labeled riboprobes for HIV RNA, two-stage p24 HIV
immunohistochemistry (IHC) and standard (ISH-IHC) double label methods to
establish viral cellular tropism.
Results: B-cell related features noted in the first 40 biopsies included 23 cases
showing secondary germinal centers and 6 with "florid" germinal centers. Of these
29 cases, 10 showed evidence of follicular involution; two had frank follicular lysis.
Three of forty cases featured only primary germinal centers and eight had no
germinal center activity. Sixteen of the forty cases featured mild to moderate paracortical expansion, and seven exhibited an exaggerated paracortical response.
Paracortical expansion is correlated with T-cell hyperplasia. Fourteen of the forty
cases had regions of "unorganized" lymphocytes and plasma cells. Only two
biopsies were without significant lymphocytosis. Lymphocytes "invading" squamous epithelium were significant in 35 cases, this phenomenan correlates with
intra-epithelial Langerhans cells, a potential reservoir for the virus. Initial ISH and
IHC studies have demonstrated that the macrophage and T-cell compartments of
the tonsil has active HIV infection.
Conclusion: This baseline study establishes the histology of the tonsil during
the early phases of HIV infection, Surprisingly, there is evidence of germinal
center breakdown in approximately one quarter of the cases. Over half the cases
potentially featured a brisk T-cell response (paracortical expansion).
21129 1 Correlations between immunologic indices and thymic
mass in HIV infected patients following 48 weeks of
therapy with zidovudine, lamivudine and ritonavir (ZLR)
Kimberly Y. Smith1, H. Valdez2, A. Landay', E. Connick3, B. Gross4, M. Wade5,
M. Lederman2. Rush Medical College, Chicago, IL; 2Case Western Reserve
University, Cleveland, OH; 3 Unversity of Colorado, Denver, CO; 4University of
Michiga, Ann Arbor MI; 5Harvard School of Public Health, Boston, MA; USA
Objective: To ascertain if thymic mass is associated with partial immune reconstitution as measured by increases in naive CD4 (CD4+ CD45RA+/CD62L+) and
CD8 (CD8+ CD45RA+/CD62L+) lymphocytes and enhancement of delayed type
hypersensitivity (DTH) skin test responses in HIV infected pts following 48 wks of
ZLR.
Methods: Thirty pts in ACTG 375 who have completed 48 wks of therapy with
ZLR underwent chest CT scans to measure thymic mass. The scans were read by
two radiologists who were blinded to clinical data. Participants were divided into
Group 1 with thymic index <2 (minimal thymic tissue), and Group 2 with thymic
index >2 (moderate or abundant thymus tissue). The groups were compared with
regard to CD4 counts, naive CD4 and CD8 percentages and cell counts, and
DTH skin test responses.
Results: Twenty-one pts were in Group 1 and nine pts; were in Group 2.
Variable Gp 1 Gp 2 p-value Variable Gp 1 Gp 2 p-value
% Naive CD4 % Naive CD8
Median baseline 20 45.009 Median baseline 9 13.046
Median wk 48 31 51.0038 Median wk 48 17 22.352
Median change 8 5.915 Median change 6 8.811
Absolute naive CD4 CD4 count
Median baseline 44 58.0374 Median baseline 217 180.5870
Median wk 48 105 181.0360 Median wk 48 383 357.7511
Median change 67 59.5772 Median change 135 133.6429
Median age 44 35.0210 Increase # +ve DTH 35% 57%.391
Conclusions: Pts with greater thymic mass as seen by CT scan had significantly greater absolute counts and percentages of naive CD4 cells at baseline
and after 48 weeks of ZLR. However, increases in naive CD4 cells and positive
DTH skin test results in response to ZLR did not correlate with thymic mass.
Despite minimal thymic mass in Group 1, there were significant increases in
naive CD4 cell counts and percentages following 48 wks of ZLR.
S21130 HHV-6-independent HIV-1-infection of CD8+ T cells in vivo
Beni Sahai', J. Krishnan2, R. Singla2, E.S. Rector3. 'Cadham Provincial
Laboratory, 750 William Avenue, Winnipeg, MB R3C 3Y1; 2Dept. of Med
Microbiol, Univ. of Manitoba, Winnipeg, MB; 3Flow Cytometry Lab, Univ. of
Manitoba, Winnipeg, MB, Canada
Background: CD8+ T cells play crucial roles in controlling HIV replication in early
stages of infection but their anti-HIV effects diminish and numbers decline with
disease progression. We and others have shown that these cells can be targets
of HIV-1 infection in vivo but the mechanism of viral entry and its significance are
unknown. HHV-6, a ubiquitous p-herpesvirus capable of inducing CD4 expression
on CD8+ T cells, is known to be reactivated during the course of HIV-1 infection.
This study examines HIV-1 infection of CD8+ T cells at different stages of disease
and its relation with HHV-6 reactivation.

Methods: PBMC of 20 HIV-1 seropositive subjects (CD4+ T cell counts ranging
from 0 to 950/mm3) were examined for the presence of HIV-1-infected CD8+ T
cells by PCR-quantitation of HIV-1 provirus in >98% purified CD8+ T cells and/or
by flow cytometric detection of gp120 and CD8 co-expression. HHV-6 reactivation
was monitored by a multiplex PCR for semi-quantitative detection and distinction
of human p-herpesviruses (CMV, HHV-6 and HHV-7). Levels of p24 antigen and
IL2 were assayed by commercial immunoassays, and HIV-1 RNA by a competitive
PCR. Nine study subjects were on HAART.