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Biomedical subjects

G Tambussi

Publications and source records attributed to G Tambussi.

At least 19 recordsLinked to original sources
PubMed2001

Efficacy of low-dose intermittent subcutaneous interleukin (IL)--2 in antiviral drug--experienced human immunodeficiency virus--infected persons with detectable virus load: a controlled study of 3 il-2 regimens with antiviral drug therapy.

To evaluate the safety and efficacy of 3 regimens of intermittent subcutaneous (sc) interleukin (IL)--2 in a phase 2 study, 61 antiviral drug-experienced human immunodeficiency virus (HIV)--positive patients were randomly assigned to one of the following study arms: antiretroviral therapy (ART) plus IL-2 (12 million IU [MIU] by continuous intravenous infusion, followed by 7.5 MIU twice a day, sc, every 8 weeks); ART plus IL-2 (7.5 MIU twice a day, sc, every 8 weeks); ART plus IL-2 (3 MIU twice a day, sc, every 4 weeks); or ART alone. A significant increase of circulating CD4 cells was observed in IL-2--treated subjects, compared with those given ART alone. Low doses of IL-2 were better tolerated. Despite the incomplete suppression of viral replication, IL-2 with ART did not increase either plasma viremia or cell-associated HIV DNA levels. Low doses of intermittent sc IL-2 induced a stable increase of peripheral CD4 cells that was indistinguishable from those associated with higher, less well-tolerated doses of IL-2.

Adult↗
PubMed2001

Expression and activation of a C-terminal truncated isoform of STAT5 (STAT5 Delta) following interleukin 2 administration or AZT monotherapy in HIV-infected individuals.

Intermittent administration of recombinant interleukin-2 (rIL-2) to individuals infected with human immunodeficiency virus (HIV) has been shown to raise and maintain the absolute number of circulating CD4(+) T cells to normal or near normal levels. One of the signaling pathways triggered by IL-2 is the Janus kinase-signal transducer and activator of transcription (JAK-STAT). In particular, IL-2 activates the tyrosine kinases JAK1 and JAK3 and the transcription factors STAT3 and STAT5. We have previously observed that most HIV(+) individuals, unlike healthy seronegative controls, show a constitutive activation of STAT1 and a C-terminal truncated isoform of STAT5 (STAT5 Delta). In the present study, we have analyzed the protein level and activation state of STAT5 isoforms expressed in peripheral blood mononuclear cells of two HIV-infected individuals who showed a good or a poor response to intermittent IL-2 administration, respectively, and of a single individual before and after initiation of Zidovudine monotherapy. We provide evidence that both therapeutic interventions enhanced the expression and activation of the C-terminal truncated isoform of STAT5 (STAT5 Delta) in vivo.

Adult↗
PubMed2001

Acute self-limiting hepatitis C after possible sexual exposure: sequence analysis of the E-2 region of the infected patient and sexual partner.

We describe a case of symptomatic acute infection with HCV in a woman whose sexual partner had chronic hepatitis C. The patient cleared HCV RNA 8 weeks after the onset of acute hepatitis and was found to be persistently HCV-RNA negative during 90 weeks of follow-up. Part of the E-2 region of HCV was directly sequenced in the patient and her sexual partner. Four local controls with subtype-1a infection and 9 1a isolates obtained from GenBank were analyzed. The average nucleotide divergence between the sequences of the infected patient and her sexual partner was 5.1%, compared with an average nucleotide divergence of 19.4% (range 16.6-21.8%) between the sequences of the patient and those of controls. Comparison of the phylogenetic trees in the partial E-2 region showed that the sequence of the patient was closely related to that of her sexual partner. Our findings suggest that the infection was transmitted to the patient from her sexual partner. The resolution of acute hepatitis C in this case was probably related to the host rather than to intrinsic characteristics of the HCV genome.

Acute Disease↗
PubMed2000

Virological and immunological responses to HAART in asymptomatic therapy-naive HIV-1-infected subjects according to CD4 cell count.

OBJECTIVE: When to start highly active antiretroviral therapy (HAART) in asymptomatic chronically HIV-1-infected subjects with CD4 cell counts of 300 x 10(6)-500 x 10(6)/l is debated extensively. Retrospective analyses of virological and immunological responses following HAART have been evaluated in both blood and lymph nodes according to pre-treatment levels of CD4 cells either above or below 500 x 10(6)/l. DESIGN: Open-label, observational, non-randomized, prospective study. SETTING: Outpatients attending the Centre of Clinical Investigation in Infectious Diseases, Centre Hospitalier Universitaire Vaudois, University of Lausanne, Switzerland. PARTICIPANTS: Fifty-four HIV-1-infected antiretroviral-naive subjects with CD4 cell count > or = 250 x 10(6)/l and plasma viraemia > or = 5000 copies/ml who had been treated with HAART for at least 48 weeks. Controls were 49 HIV-negative subjects. INTERVENTIONS: All patients received abacavir, nelfinavir, saquinavir soft gel capsules, and amprenavir in varying combinations for 72 weeks. MAIN OUTCOME MEASURES: The extent of immune reconstitution following HAART in 43 and 11 subjects with either more or fewer than 500 x 10(6) CD4 cells/l at baseline was evaluated in blood and lymph node, and compared with immunological measures observed in 49 HIV-negative controls. RESULTS: After 48 weeks of therapy, plasma viraemia was suppressed effectively in both groups of patients. Normalization of both CD4 cell count in blood, divided equally between memory and naive cells, and percentage of CD4 cells in lymph nodes occurred in the two groups. Consistently, the net increase over baseline in CD4 cell count and in memory and naive CD4 subsets was greater in patients with fewer than 500 x 10(6) CD4 cells/l at baseline. Recovery of HIV-specific responses was similar in the two groups. CONCLUSIONS: This study suggests that virological and immunological responses are comparable in asymptomatic therapy-naive HIV-1-infected subjects with CD4 cell counts above or below 500 x 10(6)/l.

Adult↗
PubMed2000

Immunological and virological responses in HIV-1-infected adults at early stage of established infection treated with highly active antiretroviral therapy.

OBJECTIVE: To evaluate the immunological and virological responses to highly active antiretroviral therapy (HAART) in blood and lymphoid compartments of HIV-1-infected patients at an early stage of infection. DESIGN: An open-label, observational, non-randomized, prospective trial of outpatients attending the Centre of Clinical Investigation in Infectious Diseases, Centre Hospitalier Universitaire Vaudois, University of Lausanne, Switzerland. SUBJECTS: Forty-one antiretroviral-naive HIV-1-infected adults with 400 CD4 T cells/microl or greater and 5000 plasma HIV-1-RNA copies/ml or greater were enrolled, and 32 finished the study. Forty-nine HIV-negative individuals were included as controls. All subjects gave written informed consent. INTERVENTIONS: All patients received abacavir 300 mg by mouth every 12 h and amprenavir 1200 mg by mouth every 12 h for 72 weeks. MAIN OUTCOME MEASURES: The extent of immune reconstitution in blood and lymph nodes after 72 weeks of HAART was evaluated, and compared with immunological measures of 49 HIV-negative subjects. RESULTS: Virus replication was effectively suppressed (-3.5 log10 at week 72). Substantial increments of CD4 T cell count in blood and percentage in lymph nodes were observed over time, and these measures were comparable to HIV-negative subjects by week 24 in blood and by week 48 in lymph nodes. The increase was equally distributed between naive and memory CD4 T cells. Recovery of HIV-specific CD4 responses occurred in 40% of patients. CONCLUSION: The initiation of HAART at an early stage of established HIV infection induces systemic quantitative normalization of CD4 T cells, a partial recovery of HIV-specific CD4 cell responses, and effective and durable suppression of virus replication.

Adolescent↗
PubMed2000

Long-term kinetics of T cell production in HIV-infected subjects treated with highly active antiretroviral therapy.

The long-term kinetics of T cell production following highly active antiretroviral therapy (HAART) were investigated in blood and lymph node in a group of HIV-infected subjects at early stage of established infection and prospectively studied for 72 wk. Before HAART, CD4 and CD8 T cell turnover was increased. However, the total number of proliferating CD4(+) T lymphocytes, i.e., CD4(+)Ki67(+) T lymphocytes, was not significantly different in HIV-infected (n = 73) and HIV-negative (n = 15) subjects, whereas proliferating CD8(+)Ki67(+) T lymphocytes were significantly higher in HIV-infected subjects. After HAART, the total body number of proliferating CD4(+)Ki67(+) T lymphocytes increased over time and was associated with an increase of both naive and memory CD4(+) T cells. The maximal increase (2-fold) was observed at week 36, whereas at week 72 the number of proliferating CD4(+) T cells dropped to baseline levels, i.e., before HAART. The kinetics of the fraction of proliferating CD4 and CD8 T cells were significantly correlated with the changes in the total body number of these T cell subsets. These results demonstrate a direct relationship between ex vivo measures of T cell production and quantitative changes in total body T lymphocyte populations. This study provides advances in the delineation of the kinetics of T cell production in HIV infection in the presence and/or in the absence of HAART.

Adult↗
PubMed2000

CCR5-reactive antibodies in seronegative partners of HIV-seropositive individuals down-modulate surface CCR5 in vivo and neutralize the infectivity of R5 strains of HIV-1 In vitro.

Exposure to HIV does not necessarily result in infection. Because primary HIV infection is associated with CCR5-tropic HIV variants (R5), CCR5-specific Abs in the sera of HIV-seronegative, HIV-exposed individuals (ESN) might be associated with protection against infection. We analyzed sera from ESN, their HIV-infected sexual partners (HIV+), and healthy controls (USN) searching for CCR5-specific Abs, studying whether incubation of PBMC with sera could prevent macrophage inflammatory protein 1 beta (Mip1 beta) (natural ligand of CCR5) binding to CCR5. Results showed that Mip1 beta binding to CCR5 was not modified by sera of either 40 HIV+ or 45 USN but was greatly reduced by sera of 6/48 ESN. Binding inhibition was due to Abs reactive with CCR5. The CCR5-specific Abs neutralized the infectivity of primary HIV isolates obtained from the corresponding HIV+ partners and of R5-primary HIV strains, but not that of CXCR4-tropic or amphitropic HIV strains. Immunoadsorption on CCR5-transfected, but not on CXCR4-transfected, cells removed CCR5-specific and virus-neutralizing Abs. Epitope mapping on purified CCR5-specific Abs showed that these Abs recognize a conformational epitope in the first cysteine loop of CCR5 (aa 89-102). Affinity-purified anti-CCR5-peptide neutralized the infectivity of R5 strains of HIV-1. Anti-CCR5 Abs inhibited Mip1beta-induced chemotaxis of PBMC from healthy donors. PBMC from two ESN (with anti-CCR5 Abs) were CCR5-negative and could not be stimulated by Mip1beta in chemotaxis assays. These results contribute to clarifying the phenomenon of immunologic resistance to HIV and may have implications for the development of a protective vaccine.

Binding Sites, Antibody↗
PubMed2000

Initiation of antiretroviral therapy during primary HIV-1 infection induces rapid stabilization of the T-cell receptor beta chain repertoire and reduces the level of T-cell oligoclonality.

Major T-cell receptor beta chain variable region (TCRBV) repertoire perturbations are temporally associated with the down-regulation of viremia during primary human immunodeficiency virus (HIV) infection and with oligoclonal expansion and clonal exhaustion of HIV-specific cytotoxic T lymphocytes (CTLs). To determine whether initiation of antiretroviral therapy (ART) or highly active antiretroviral therapy (HAART) during primary infection influences the dynamics of T-cell-mediated immune responses, the TCRBV repertoire was analyzed by semiquantitative polymerase chain reaction in serial blood samples obtained from 11 untreated and 11 ART-treated patients. Repertoire variations were evaluated longitudinally. Stabilization of the TCRBV repertoire was more consistently observed in treated as compared with untreated patients. Furthermore, the extent and the rapidity of stabilization were significantly different in treated versus untreated patients. TCRBV repertoire stabilization was positively correlated with the slope of HIV viremia in the treated group, suggesting an association between repertoire stabilization and virologic response to treatment. To test whether stabilization was associated with variations in the clonal complexity of T-cell populations, T-cell receptor (TCR) heteroduplex mobility shift assays (HMAs) were performed on sequential samples from 4 HAART-treated subjects. Densitometric analysis of HMA profiles showed a reduction in the number of TCR clonotypes in most TCRBV families and a significant decrease in the total number of clonotypes following 7 months of HAART. Furthermore, a biphasic decline in HIV-specific but not heterologous CTL clones was observed. This indicates that ART leads to a global reduction of CD8(+) T-cell oligoclonality and significantly modulates the mobilization of HIV-specific CTL during primary infection. (Blood. 2000;95:1743-1751)

Acute Disease↗
PubMed2000

Neurological symptoms during primary human immunodeficiency virus (HIV) infection correlate with high levels of HIV RNA in cerebrospinal fluid.

This analysis involves 22 patients with diagnosed symptomatic human immunodeficiency virus (HIV) infection. Neurologic symptoms were present in 11 patients, ranging from severe and persistent headache to clinical signs suggestive of meningitis. A strong correlation between neurological symptoms and cerebrospinal fluid (CSF) viral load was found. The mean CSF HIV ribonucleic acid (RNA) level was 4. 12 log for patients with neurological symptoms and 2.58 log for patients without neurological symptoms (P<.00001). Plasma viral load alone does not correlate or predict central nervous system (CNS) involvement. In our sample of patients, HIV RNA levels could be detected in most patients regardless of the presence of neurological symptoms. Moreover, early treatment including drugs with high levels of penetration in the CNS must be considered for patients with primary HIV infection.

Central Nervous System Viral Diseases↗
PubMed2000

Predicting the duration of antiviral treatment needed to suppress plasma HIV-1 RNA.

Effective therapeutic interventions and clinical care of adults infected with HIV-1 require an understanding of factors that influence time of response to antiretroviral therapy. We have studied a cohort of 118 HIV-1-infected subjects naive to antiretroviral therapy and have correlated the time of response to treatment with a series of virological and immunological measures, including levels of viral load in blood and lymph node, percent of CD4 T cells in lymph nodes, and CD4 T-cell count in blood at study entry. Suppression of viremia below the limit of detection, 50 HIV-1 RNA copies/mL of plasma, served as a benchmark for a successful virological response. We employed these correlations to predict the length of treatment required to attain a virological response in each patient. Baseline plasma viremia emerged as the factor most tightly correlated with the duration of treatment required, allowing us to estimate the required time as a function of this one measure.

Adult↗
PubMed1999

In vivo administration of recombinant IL-2 to individuals infected by HIV down-modulates the binding and expression of the transcription factors ying-yang-1 and leader binding protein-1/late simian virus 40 factor.

Leader binding protein-1 (LBP-1)/late SV40 factor (LSF) and ying yang-1 (YY1) transcription factors are involved in the regulation of HIV expression. In particular, YY1 and LBP-1 have been shown to cooperate in repressing HIV-1-long terminal repeat reporter gene expression by in vitro cotransfection experiments. However, no information is available on the levels of expression and activation of these transcription factors in PBMC of HIV-infected individuals. Therefore, we have evaluated the expression and DNA binding activity of YY1 and LBP-1 (LSF) in PBMC of HIV-infected individuals before, during, and after administration of IL-2 in association with antiretroviral therapy (ART), a regimen under consideration for broad clinical use in this disease based on its ability to stably raise the absolute number of circulating CD4+ T lymphocytes. Both YY1- and LBP-1 (LSF)-DNA binding were profoundly down-modulated during administration of IL-2/ART, and a proteolytic activity probably responsible for the reduced expression of the two cellular transcription factors was found activated in PBMC of individuals receiving the immunotherapeutic regimen. This study is the first evidence of modulation of cellular transcription factors following IL-2/ART administration and provides a potential correlate of the transient raises in plasma viremia early reported in patients receiving IL-2 in the absence of ART, thus underscoring the importance of always administering this cytokine to HIV-infected individuals together with potent antiretrovirals.

Adult↗
PubMed1999

Viral load and burden modification following early antiretroviral therapy of primary HIV-1 infection.

OBJECTIVE: The aim of this study was to monitor the effect on viral DNA and RNA of early treatment with highly aggressive antiretroviral therapy (HAART), in comparison with zidovudine (ZDV) monotherapy or no treatment in subjects with primary HIV-1 infection (PHI). DESIGN AND METHODS: Of the 28 patients selected, four were untreated, four received ZDV alone, 10 received a triple combination (ZDV, lamivudine (3TC) and saquinavir (SQV)) and 10 received a quadruple combination (ZDV, 3TC, SQV and ritonavir (RTV)). Seroconversion was monitored by means of Western blot profile analysis. A quantitative polymerase chain reaction (PCR) assay in the HIV gag region was used to monitor viral DNA and the nucleic acid sequence based amplification (NASBA) system for viraemia (HIV-RNA). RESULTS: There was a certain level of heterogeneity in the baseline values of HIV-DNA and RNA. Early HAART led to a rapid recovery in the number of CD4 cells and the CD4/CD8 cell ratio and a reduction in HIV-RNA to undetectable levels, which was significantly greater than in the untreated patients or those treated with ZDV. Although a reduction in DNA levels was also observed in the HAART-treated subjects, this variation was not significant. CONCLUSIONS: The parameters of viral replication and CD4 cell recovery were only slightly better in the patients receiving ZDV monotherapy than in the untreated patients, thus confirming that the course of the infection is hardly affected by the monotherapy. The early introduction of HAART greatly reduces plasma viraemia and restores the number of CD4 cells for up to 1 year. HIV-DNA remains detectable, although at low levels, thus confirming that the early established reservoir of infected cells is little affected. Longer periods of observation and the introduction of complementary approaches, such as immunomodulatory therapies, will provide further information concerning the possibility of radically interfering with the natural evolution of the disease.

Adult↗
PubMed1999

Study on mutations and antiretroviral therapy (SMART): preliminary results.

Resistance to antiretroviral drugs is believed to be an important cause of treatment failure in human immunodeficiency virus (HIV)-infected patients, however, the role of susceptibility assays in the management of these individuals needs to be defined. SMART (study on mutations and antiretroviral therapy) is an ongoing study on mutations and antiretroviral therapy focused particularly on HIV-infected patients treated with two nucleoside analogue reverse transcriptase inhibitors (NRTIs). Plasma HIV-1 RNA was assessed by NASBA (nucleic acid sequence-based amplifications) (Organon Teknika, Boxtel, The Netherlands) with a detection limit of 80 copies/ml, whereas resistance was assessed by direct sequencing of the RT pol gene in patients with detectable viraemia, and by Antivirogram (Virco) in non-responder patients. The preliminary results of this study show that both genotypic and phenotypic assays identify mutated viral strains in the majority of patients failing a dual regimen. Furthermore, the data indicate a high rate of genotypic resistance to lamivudine in both responders and non-responders, a high rate of phenotypic resistance to lamivudine in non-responders, no genotypic resistance to didanosine and stavudine in responders, and a very low rate of both genotypic and phenotypic resistance to didanosine and stavudine in non-responders.

Anti-HIV Agents↗
PubMed1998

Prevalence of mutation associated to resistance with nucleoside analogues in a cohort of naïve HIV-1 positive subjects during the period 1984-1997.

We examined samples from 98 naïve HIV-1 positive patients with the seroconversion period between 1984 and 1997, 64 of whom with a diagnosed primary infection. We observed a progressive increase in the percentage of patients harboring mutations associated with zidovudine resistance, starting from 8% during the period 1987-1994 to 20% and 36% in patients with HIV infection diagnosed during 1996 and 1997 respectively. The small number of patients analyzed in groups 3 and 4 is an important limitation to establish the real increase in the prevalence of mutations we observed during the past two years. However, it is important to underline the trend and, in our opinion, further studies to better define the relevance of such phenomenon in the clinical practice must be performed.

Adult↗