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

528 Abstracts 31165-31169

12th World AIDS Conference

Conclusion: The normal levels of MBP observed among these children lead
us to surmise that there would be a disturbance in the production of this protein,
with a diminished opsonization and consequently, bacterial infections episodes.
110* / 31165 Down regulation of CD8+ T-cell expansions in HIV
patients receiving highly active combination
therapy
Guy Gorochov1, U.N. Neuman2, C. Parizot1, T. Li1, B. Autran', P. Debre1.
SCervi-Ura 625 - Hopital Pitie-Salpetriere 83, Bvd de I'H6pital - 75013 Paris,
France; 2Bar-llan University Ramat-Gan, Israel
Background: In a recent work (Gorochov G. et al. Nature Med. 4, Feb. 1998)
we showed that the efficient control of HIV replication under combination antiviral
therapy allows CD4 cell count rise but also, and more importantly, qualitative
modifications of the CD4 repertoire balance. In contrast, drastic restrictions in
CD8+ T cell repertoire usage, corresponding to selective clonal expansions, were
still observed after 6 months of treatment.
Methods: We followed 5 HIV infected patients up to 20 months after the onset of an active triple association therapy including an HIV protease inhibitor. 4
out of 5 patients did not receive any previous antiviral therapy. The longitudinal
variations of T cell receptor / (TCR ) repertoire perturbation were quantified by
combining an analysis of CDR3 (complementary determining region 3) polymorphism of the TCR transcripts and cytofluorometric analysis using a large panel of
BV family-specific monoclonal antibodies.
Results: Peripheral blood CD8 TCR repertoires returned to normal after 12
months of active anti retroviral treatment in 3 out of 5 cases. In such cases, it is
likely that most of the cells within the pre-treatment expansions have died from
apoptosis or have been redistributed. Concomitantly, the proportion of activated
cells (CD38+ or DR+) amongst the CD8 subset was very significantly reduced.
Triple therapy was not successful in one case (no increase in CD4 absolute
counts and persistent viremia). In that patient, massive CD8 clonal expansions
(one clone accounting for up to 53% of all CD8 cells) persisted during the time of
follow up (12 months). Finally, in the 5th patient studied, the pretreatment antigendriven clonal expansions did not persist but, nevertheless, the CD8 repertoire did
not return to a polyclonal configuration. New clonal expansions, confirmed to be
different by DNA sequencing, became clearly detectable 3 months after the onset
of the antiviral treatment, at a time when that patient presented with biological
signs of hepatitis B reactivation. In comparison, CD8 repertoires of uninfected
controls, and also of untreated HIV patients, show much more stability over time.
Conclusion: In patients with chronic HIV infection, the extent of oligoclonal
CD8 T cell proliferation appears to be far greater than has been previously recognized. Nevertheless, 12 months of efficient antiviral therapy are enough for CD8
repertoires to return to normal in the absence of any other active viral infection. A
tight control of HIV replication correlates with profound modifications of the CD8
repertoire, which slowly returns to a resting state.
213*/31166 The expression of CD38 and DR are markers of
immune activation and disease progression in
HIV+ children
Rafael Sirera1, A. Bayona', F. Carbonell2, D. Perez-Tamarit3, M.C. Otero3,
F. Asensi3, A. Gonzalez-Molina1. 'l munologia + Centro de Investigacion Hospital
la Fe - Avda. de Campanar, 21 (46009-Valencia); 2U?citometria de Flujo. Centro
de Transfusiones-Comunidad Valencia; 3lnfeccios-Hospital Infantil-la Fe,
Valencia, Spain
Background: CD38 is a glycoprotein expressed on early hematopoietic cells that
is lost during cell maturation and re-expressed during cell activation (like during
viral infections). CD38 can transmit positive or negative signals regulating T and
B lymphocyte proliferation and differentiation (inducing cytokine synthesis). In
HIV infected children we look for a predictor of disease progression and also
characterise patient with poor prognosis.
Methods: We investigated the expression of CD38 and DR within CD4 and
CD8 lymphocytes by three-colour flow cytometry. Age matched control were children born to HIV+ mothers that seroreverted (SR, n = 22). Attending to the age
of presenting severe CD4 lymphopenia (CD4 < 15%) HIV+ children were divided
in three groups: a) Fast Progressors (FP, n = 7) before 2 years of age. b) Slow
Progressors (SP, n = 16) from 7 to 9 years of age. c) Long Term Non Progressors
(LTNP, n = 4) with normal CD4 cell counts and older than 10 years.
Results: In HIV-children CD4CD38 lymphocytes changes gradually to be from
40% at birth to 30% at the age of 9. FP present at birth low expression of
CD4CD38 lymphocytes that increases during lymphopenia. SP and LTNP show
normal percentages of CD4CD38 lymphocytes diminishing in the former during
the severe lymphopenia. The physiologic decrease in the number of CD8 lymphocytes reaches a plateau at the age of 4 years in control children with low
expression of DR and CD38 (20-15%). On the other HIV+ children that progress
to AIDS show, 2 to 3 years prior to present severe CD4 depletion, a CD8 lymphocytosis with a marked increase of activation molecules expression (CD38 and DR
up to 60%). LTNP also show a slight CD8 lymphocytosis (with activation markers)
not as significant as the other.

Conclusions: The significant increase of activation markers in lymphocytes of
HIV infected children reflects the chronic hyperactivation of the immune system.
The overexpression of CD38 and DR precedes the severe depletion of CD4
lymphocytes, and can predict the progression to AIDS in HIV+ children.

I31167 Interleukin-8 receptor down-regulation on
polymorphonuclear neutrophils of individuals infected
with HIV-1 and Mycobacterium tuberculosis is associated
with impaired cell function
Caroline Tiemessen1'2, S. Meddows-Taylor2, D.J. Martin2. 'National Institute for
Virology Private Bag X4 Sandringham 2131; 2MRC AIDS Virus Res. Unit, Nat.
Inst. for Virology, Johannesburg, South Africa
Objectives: To determine the expression of the two human IL-8 receptors, designated IL-8RA (CXCR-1) and IL-8RB (CXCR-2), on the surface of whole blood
polymorphonuclear leukocytes (PMN) and further to determine PMN function in
response to IL-8.
Methods: Sixteen subjects each were included in 4 study groups: healthy
blood donors (ND), patients with pulmonary tuberculosis (TB), HIV-1 seropositive patients (HIV), and HIV-1 seropositive patients with pulmonary tuberculosis
(HIV/TB). The expression of the two IL-8 receptors was determined on whole
blood PMN using IL-8R-specific antibodies. PMN calcium flux, chemotaxis and
degranulation in response to IL-8 were determined by Fura-2 fluorescence, a
Transwell chemotaxis assay, and /-glucuronidase release assay, respectively.
Results: A significant reduction in the percentage of PMN expressing IL-8RA
and IL-8RB and in their respective fluorescence intensities was found in TB, HIV,
and HIV/TB groups compared with that obtained for the ND group. The greatest
down-regulation of both receptors occurred in the HIV/TB group. Calcium mobilization, chemotaxis and degranulation in response to IL-8 were all decreased
in a group of HIV/TB patients when compared to healthy controls. Furthermore,
these diminished functions were associated with reduced IL-8RA and IL-8RB
expression on whole blood PMN.
Conclusion: The impairment of IL-8-dependent PMN functions is associated
with the reduced expression of IL-8 receptors on these cells. These results are
consistent with clinical findings of increased susceptibility to secondary bacterial and fungal infections, particularly in patients coinfected with HIV-1 and M.
tuberculosis.
271 * /31168 Telomere length and telomerase analysis in blood
and lymphnodes provide no evidence for increased
CD4+ T-cell production in HIV-1 infection
Katja C. Wolthers', S.A. Otto', A.J. Noest2, G.B.A. Wisman3, S. Fleury5, R.J. de
Boer2, F. Miedema4. Clin. Virology-Immunology, C.L.B., Plesmanlaan 125,
1066 CX, Amsterdam; 2 Theoretical Biology, University of Utrecht, Utrecht;
3Internal Oncology, A.Z.G., Gronigen; 4Clin. Viro-lmm., C.L.B., Hum. Retrovir.,
A.M.C., Amsterdam, Netherlands; 5Nedecine Interne, Hopital de Beaumont,
Laussane, Switzerland
Objectives: Normal CD41 T-cell telomere restriction fragments (TRF) lengths
in HIV infection indicated that exhaustion of renewal is not the cause of CD41
T-cell decline. Stable CD4' TRF length could be caused by high telomerase activity or HIV-induced death of dividing cells, thereby masking increased turnover.
Therefore, telomerase activity was measured. TRF length was analyzed in blood
and lymphnode CD4~ and CD8+ T cells, and in blood CD4+CD45RA+ and
CD4+CD45RO+ T cells which were interpreted in terms of production rates by a
mathemathical model.
Methods: Telomerase activity was measured by the TRAP assay. TRF lengths
were analyzed by Southern Blot technique. HIV-infected individuals were compared to healthy controls or studied longitudinally.
Results: In HIV-infected individuals, telomerase activity was normal in blood
CD4+, CD4+CD45RA+, CD4+CD45RO+, and CD8 T cells. In lymphnode CD4+
and CD8+ T cells, TRF length was not significantly different from blood, and
telomerase activity was normal. Induction of telomerase was normal in CD4+ and
CD8+ T cells after in vitro stimulation. Analysis of TRF length of CD4+CD45RA+
and CD4+CD45RO+ T cells during the course of HIV-1 infection showed normal
TRF length and shortening rates. Mathematical modeling of population dynamics
showed that normal TRF length of CD4+CD45RA+ cells in HIV-1 infection is compatible with a maximal 4-fold increase in CD4+CD45RA+ T cell productivity as a
result of HIV-related killing. For CD4+CD45RO+ T cells in HIV-1 infection, normal
TRF length is compatible with only a 2-fold increased productivity.
Conclusion: Normal telomerase activity implies that TRF length can be used
as a marker for cell replication in HIV-1 infection. Normal CD4~ T-cell TRF length
and telomerase activity in HIV-1 infection together with slow regenerating capacity
of the immune system indicate that a limited rate of renewal is the cause of CD4+
T-cell depletion.
31169 | Anergy and dysfunction of CD4+ and V-y2V62+
lymphocytes associated with mycobacterium bovis
BCG-induced disease in SIV-infected monkeys
Zheng W. Chen', D. Zhou2, D. Lee-Parritz3, L. Chalifoux3, M. Simon3,
N. Letvin2, Y. She2. 1330 Brookline Ave RE113 Boston MA 02215; 2BIDMC
Harvard Med Boston MA; 3NERP RC Harvard Med Southboro MA, USA

Objectives: To explore immunopathogenic mechanisms underlying the increased
susceptibility to tuberculosis in AIDS virus-infected individuals.
Design and Methods: Previous studies have demonstrated that macaques
coinfected with SIV and Mycobacterium bovis BCG can develop disseminated tuberculosis-like disease and an acceleration in clinical progression of their AIDS. In
the present study, the SIV/BCG coinfection model has been employed to explore
CD4+ and T cell receptor (TCR) y8+ cell responses to mycobacterial peptidic