Lopinavir/ritonavir monotherapy versus current treatment continuation for maintenance therapy of HIV-1 infection: the KALESOLO trial.

OBJECTIVES: We evaluated a monotherapy maintenance regimen with lopinavir/ritonavir versus continuing current combined antiretroviral treatment (cART) in HIV patients with suppressed plasma HIV-1 RNA. PATIENTS AND METHODS: This was an open-label, non-inferiority, multicentre trial in 23 sites in France. Adults were randomized if they had no history of virological failure while receiving a protease inhibitor, maintained HIV-1 RNA <50 copies/mL for at least 6 months and did not change cART during the last 3 months. The primary endpoint was the proportion of patients with HIV-1 RNA <50 copies/mL at Week 48 (non-inferiority margin set at -12%) with missing data and treatment modification considered as failure. The trial has been registered in ClinicalTrials.gov under the identifier NCT00140751. RESULTS: At Week 48, 84% (73/87) of patients in the lopinavir/ritonavir monotherapy group met the primary endpoint compared with 88% (87/99) in the cART group [difference, -4.0%, lower limit of 90% two-sided confidence interval (CI) for difference, -12.4%]. In secondary analysis with success defined as plasma HIV-1 RNA <400 copies/mL, 87% (76/87) of patients in the lopinavir/ritonavir monotherapy group were virologically suppressed compared with 88% (87/99) in the cART group (difference, -0.5%, lower limit of 90% two-sided CI for difference, -8.5%). If antiretroviral treatment intensification was taken into account, 91% (79/87) of patients in the lopinavir/ritonavir monotherapy group met the primary endpoint compared with 88% (87/99) in the cART group (difference, +2.9%, lower limit of 90% two-sided CI for difference, -4.5%). Failures of lopinavir/ritonavir monotherapy did not show acquired resistance mutations in the protease gene. CONCLUSIONS: Lopinavir/ritonavir monotherapy did not achieve non-inferiority versus cART for maintaining plasma HIV-1 RNA <50 copies/mL. Nevertheless, the incidence of virological failure was low (mostly with HIV-1 RNA <400 copies/mL) and easily managed by treatment intensification.

Long-term persistence of memory B cells specific for hepatitis B surface antigen in HIV-1-infected patients.

To investigate the maintenance of long-term memory B cells specific for hepatitis B surface antigen (HBsAg), purified blood B cells were polyclonally stimulated and cells secreting antibodies directed to HBsAg (HBs-SC) enumerated by ELISpot. HBs-SC were found in 18/20 HIV-1-infected patients with either natural or vaccinal immunity to hepatitis B virus, including six subjects with serum anti-hepatitis B surface antibody levels less than 10 mIU/ml. A lower number of HBs-SC was found in HBsAg-vaccinated patients compared with vaccinated controls.

Unintegrated HIV-1 provides an inducible and functional reservoir in untreated and highly active antiretroviral therapy-treated patients.

BACKGROUND: The presence of HIV-1 preintegration reservoir was assessed in an in vitro experimental model of latent HIV-1 infection, and in patients treated or not with highly active antiretroviral therapy (HAART). RESULTS: In resting CD4+ T lymphocytes latently infected in vitro with HIV-1, we demonstrated that the polyclonal activation induced a HIV-1 replication, which could be prevented by the use of an HIV-1 integrase inhibitor. We also showed that this reservoir was labile since the rescuable HIV-1-antigens production from unintegrated HIV-1 genomes declined over time. These data confirm that our experimental approach allows the characterization of a functional unintegrated HIV-1 reservoir. We then explored the preintegration reservoir in HIV-1-infected patients. This reservoir was detected in 11 of 12 untreated patients, in 4 of 10 sustained responders to HAART, and in one incomplete responder. This reservoir was also inducible, labile, and anti-HIV-1 integrase drug inhibited its induction. Finally, this reservoir was associated with the presence of spontaneous HIV-1 antigens producing CD4+ T cells in blood from 3 of 3 untreated patients and 2 of 2 sustained responders to HAART harboring a preintegration reservoir. CONCLUSION: This preintegration phase of HIV-1 latency could be a consequence of the ongoing viral replication in untreated patients and of a residual viral replication in treated patients.

Interferon-alpha restores HIV-induced alteration of natural killer cell perforin expression in vivo.

OBJECTIVE: The percentage and the activity of natural killer (NK) cells are known to be decreased in HIV-infected patients. However, the mechanisms responsible for this NK deficiency are poorly understood. Because of the role of NK cells in the host defence against microbial infections, this defect contributes to the virus-induced immune deficiency. The aim of the present study was to better understand this defect in order to be able to restore NK function in HIV infection. DESIGN AND METHODS: The expression of the cytolytic mediators perforin and granzyme A was analysed by flow cytometry, the lytic activity of peripheral blood NK cells of HIV-infected patients was analysed by cytotoxic assay, and the expression of perforin was followed during administration of interferon (IFN)alpha attached to polyethylene glycol (PEG)-IFNalpha. RESULTS: The lytic activity and the expression of perforin and granzyme A was low in NK cells of infected individuals in comparison with normal control volunteers. In both groups NK cytotoxic capacity was linked to perforin expression. The low perforin expression in HIV-infected subjects negatively correlated with HIV RNA plasma level. administration of PEG-IFNalpha restored perforin expression even in patients whose viral load was not reduced by this treatment. CONCLUSIONS: These results suggest that HIV-induced NK deficiency could be partly mediated by a defect in perforin and granzyme A expression, and that PEG-IFNalpha could be used in infected subjects to directly improve their natural immunity in addition to eventually reducing their viraemia.

Perforin expression in T cells and virological response to PEG-interferon alpha2b in HIV-1 infection.

OBJECTIVE AND DESIGN: Interferon alpha (IFNalpha), which is known to directly inhibit the HIV-1 replicative cycle and to increase the activity of cytotoxic T lymphocytes (CTL), is being tested as an anti-HIV agent. As CTL play a major role in immune defence against HIV, we wanted to further characterize CTL activity and the effect of IFNalpha on it. METHODS: We followed by flow cytometry the intracellular expression of the key mediator of cytotoxicity, perforin, in peripheral blood T cells of patients treated with IFNalpha. RESULTS: We observed that the percentage of T cells harbouring perforin was higher in infected subjects than in non-infected controls. Administration of IFNalpha2b attached to polyethylene glycol increased this perforin expression further and reduced viral load (P = 0.010). The increase in the percentage of T cells expressing perforin correlated with IFNalpha-induced decrease in viral load (r, 0.753; P = 0.003). In addition, the level of perforin expression before IFNalpha administration was inversely correlated with viral load remaining after IFNalpha administration (r, -0.647; P= 0.017). CONCLUSION: The pre-therapeutic percentage of perforin-positive T cells might be a predictive marker of the virological response to IFNalpha in HIV-1-infected patients.

Dynamics of spontaneous HIV-1 specific and non-specific B-cell responses in patients receiving antiretroviral therapy.

OBJECTIVES: As spontaneous anti-HIV-1 antibody and IgG secretion by peripheral blood mononuclear cells (PBMC) reflect immune system activation by HIV-1 antigens, we evaluated the impact of antiretroviral therapies on HIV-1 specific and non-specific B cell responses. METHODS: Anti-HIV-1 antibody and non-specific IgG were measured by ELISA in supernatants of PBMC cultured during 7 day from 30 patients initiating an antiretroviral therapy at baseline, 8, 16, 24, 36 and 48 weeks. RESULTS: An early and sustained fall in plasma viral load to below the detection limit (20 copies/ml) was observed in 17 sustained responder patients (SR), whereas HIV-1 RNA remained detectable in 13 others incomplete responders. In both groups, HIV-1 specific antibody secretion decreased significantly in parallel with plasma viral load and polyclonal immunoglobulin production became similar to that of PBMC controls. However, HIV-1 specific antibody production became negative in only six SR, exhibiting a greater increase of CD4 T-cell counts and higher levels of the spontaneous HIV-1 specific IgA secretion at baseline than the other SR. CONCLUSIONS: Antiretroviral therapy induced a rapid and dramatic decrease of spontaneous HIV-1 specific and non-specific B cell responses. These results pointed out that HIV-1 specific antibody secretion persisted in 11 out of 17 SR patients, suggesting persistent immune system activation by residual HIV-1 antigens.

Detection of peripheral HIV-1-specific memory B cells in patients untreated or receiving highly active antiretroviral therapy.

OBJECTIVES: To examine whether polyclonal activation of circulating B cells, in a process that involves CD40-CD40 ligand and cytokine interactions, could induced HIV-1-specific memory B cells to synthesize HIV-1-specific antibodies. METHODS: B cells from 26 HIV-1-infected patients were cultured with a CD40L-transfected cell line plus interleukins 2 and 10 and tested for their secretion of HIV-1- and Toxoplasma gondii-specific antibodies. RESULTS: In vitro activated B lymphocytes from HIV-1-infected patients secreted anti-HIV-1-specific antibodies. B cells from HIV-1-infected patients as well as those from controls chronically infected by T. gondii synthesized T. gondii-specific antibodies. HIV-1-specific IgG-, IgA- or IgM-secreting B cells represented approximately 1 x 10(-4) to 1 x 10(-5) of total circulating B cells and 1 x 10(-2) to 1 x 10(-3) of immunoglobulin-secreting cells. HIV-1-specific memory B cells were found in 9/9 untreated patients and in 8/17 patients receiving highly active antiretroviral therapy (HAART). The other nine patients showed a normal CD40-CD40L B cell response and six of them produced T. gondii-specific antibody B cells. The follow-up of seven patients indicated that HIV-1-specific memory B cells became undetectable after 8 to 46 months of HAART, whereas T. gondii-specific memory B cells persisted in parasite coinfected patients. CONCLUSIONS: Circulating memory HIV-1-specific B cells were detected in untreated patients and in about half of the patients taking HAART, suggesting that persistent low-level ongoing viral replication is not sufficient to maintain HIV-1-specific memory B cells.

Fenofibrate improves the atherogenic lipid profile and enhances LDL resistance to oxidation in HIV-positive adults.

BACKGROUND: Low HDL-cholesterol, hypertriglyceridemia (HTG) and occurrence of small dense LDL could be involved in increased cardiovascular risk in HIV-infected patients. This study evaluates the effects of fenofibrate and/or Vitamin E on lipoprotein profile. DESIGN: Thirty-six HIV-positive adults with fasting triglycerides (TGs) > or =2 mmol/l and stable antiretroviral therapy (ART) were randomly assigned to receive either micronised fenofibrate (200 mg/day) or Vitamin E (500 mg/day) for a first period of 3 months and the association of both for an additional 3-month period. METHODS AND RESULTS: Total cholesterol, HDL-C, LDL-C, triglycerides, apoA1, apoB, apoCIII, lipoprotein composition, LDL size and LDL resistance to copper-induced oxidation were determined before initiation of fenofibrate or Vitamin E, and 3 and 6 months thereafter. Three months of fenofibrate treatment results in a significant decrease in triglycerides (-40%), apoCIII (-21%), total cholesterol (-14%), apoB (-17%) levels, non-HDL-C (-17%), TG/apoA1 ratio in HDL (-27%) associated with an increase in HDL-C (+15%) and apoA1 (+11%) levels. Moreover, fenofibrate increases LDL size and enhances LDL resistance to oxidation. Three months of Vitamin E supplementation only improves LDL resistance to oxidation and addition to fenofibrate results in a slightly greater effect. CONCLUSION: Fenofibrate therapy improves the atherogenic lipid profile in HIV-positive adults with hypertriglyceridemia.

Enumeration of latently infected CD4+ T cells from HIV-1-infected patients using an HIV-1 antigen ELISPOT assay.

BACKGROUND: Latently infected resting CD4(+) T cells carrying replication-competent HIV-1 are present in naive, chronically infected individuals as well as in those who are receiving highly active antiretroviral therapy (HAART). These cells serve as a potential source of reactivation of viral replication and remain a major obstacle for the eradication of HIV-1. OBJECTIVES: The enzyme-linked immunospot (ELISPOT) assay was adapted to the detection and the enumeration of HIV-1 antigen-secreting cells at the single cell level. We applied this test to count latently HIV-1-infected CD4(+) T cells. STUDY DESIGN: Latently infected CD4(+) T cells were assessed in an in vitro model of HIV-1-infected resting CD4(+) T cells as well as in eighteen HAART-treated and in four HIV-1-infected untreated patients. Enriched CD4(+) T cells were cultured with or without antibodies against CD3 and CD28 T cell receptors and with irradiated peripheral blood mononuclear cells from HIV-1 seronegative individuals. At the term of the cell culture, CD4(+) T lymphocytes were tested using the HIV-1 antigen ELISPOT assay. RESULTS: In the experimental HIV-1 infection model, 5579+/-4190 CD4(+) T cells secreting HIV-1 antigen were enumerated after polyclonal activation. In contrast, only 15+/-6 HIV-1 immunospots were obtained from unstimulated T cells. In all patients tested, induced HIV-1 antigen-secreting cells were measured at a frequency of 55+/-108/10(6) CD4(+) T cells. CONCLUSION: As each immunospot represents one HIV-1 antigen-secreting cell, the HIV-1 ELISPOT assay is a powerful to enumerate circulating CD4(+) T lymphocytes latently infected with HIV-1.

Close association of CD8+/CD38 bright with HIV-1 replication and complex relationship with CD4+ T-cell count.

BACKGROUND: Measuring lymphocyte activation provides information in addition to CD4(+) T-cell count for immune monitoring of HIV-1 infected patients. CD38 is a well-established activation marker that is generally analyzed on the whole population of CD8(+) T-cells. Focusing specifically on CD38 high expression (CD8(+)/CD38(bright)) may be an interesting surrogate gating strategy because CD38(bright) characterizes principally activated memory cells. METHODS: CD8(+)/CD38(bright) was investigated in 1,353 HIV-1 infected patients over a one-year period to establish relevant cutoff values and clarify the relationships of this marker with HIV-1 RNA viral load (VL) and CD4(+) T-cell count. RESULTS: The CD8(+)/CD38(bright) (>8,500 CD38 binding site per cells) is well correlated with HIV-1 VL (r = 0.87, P < 0.001) in this longitudinal follow-up of nonimmunodepressed patients that initiated antiviral therapy (ART). In aviremic patients on ART, the marker was highly predictive of VL rebound (sensitivity 93%, specificity 64% for a VL level of detection >200 copies/ml). While the CD8(+)/CD38(bright) moderately correlated with CD4(+) T-cell count independently of the VL (r = -0.37, P < 0.001), it increased dramatically in aviremic patient groups that exhibited profound CD4(+) T-cell depletion (median 39% for CD4(+) T-cell counts <50/mm(3)). This result indicates that other additional immunological and/or viral factors than readily detectable HIV-1 replication appears to be involved in T-cell activation of immunodepressed individuals. CONCLUSIONS: CD8(+)/CD38(bright) is an effective marker for monitoring T-cell activation, which is a central factor of HIV-1 pathogenesis. This gating strategy requires only a single additional staining in conventional four color CD4 protocols.

Suv39H1 and HP1gamma are responsible for chromatin-mediated HIV-1 transcriptional silencing and post-integration latency.

HIV-1 gene expression is the major determinant regulating the rate of virus replication and, consequently, AIDS progression. Following primary infection, most infected cells produce virus. However, a small population becomes latently infected and constitutes the viral reservoir. This stable viral reservoir seriously challenges the hope of complete viral eradication. Viewed in this context, it is critical to define the molecular mechanisms involved in the establishment of transcriptional latency and the reactivation of viral expression. We show that Suv39H1, HP1gamma and histone H3Lys9 trimethylation play a major role in chromatin-mediated repression of integrated HIV-1 gene expression. Suv39H1, HP1gamma and histone H3Lys9 trimethylation are reversibly associated with HIV-1 in a transcription-dependent manner. Finally, we show in different cellular models, including PBMCs from HIV-1-infected donors, that HIV-1 reactivation could be achieved after HP1gamma RNA interference.

Suppression of microRNA-silencing pathway by HIV-1 during virus replication.

MicroRNAs (miRNAs) are single-stranded noncoding RNAs of 19 to 25 nucleotides that function as gene regulators and as a host cell defense against both RNA and DNA viruses. We provide evidence for a physiological role of the miRNA-silencing machinery in controlling HIV-1 replication. Type III RNAses Dicer and Drosha, responsible for miRNA processing, inhibited virus replication both in peripheral blood mononuclear cells from HIV-1-infected donors and in latently infected cells. In turn, HIV-1 actively suppressed the expression of the polycistronic miRNA cluster miR-17/92. This suppression was found to be required for efficient viral replication and was dependent on the histone acetyltransferase Tat cofactor PCAF. Our results highlight the involvement of the miRNA-silencing pathway in HIV-1 replication and latency.

Is tenofovir involved in hypophosphatemia and decrease of tubular phosphate reabsorption in HIV-positive adults?

OBJECTIVES: Tubulopathy with hypophosphatemia have been observed in HIV-positive patients receiving a tenofovir-containing regimen. However, the real incidence and prevalence of hypophosphatemia and their relation to tubular reabsorption disorders in tenofovir-treated patients remain uncertain. The aim of our study was to explore the effect of tenofovir on phosphatemia and on tubular phosphate reabsorption. METHODS: In a first transversal study, 145 HIV-positive adults (44+/-9 years) receiving tenofovir 300 mg daily with a mean exposure of 11+/-9 months were included. In a second prospective study, 29 HIV-positive antiretroviral experienced adults (44+/-10 years) were evaluated before introduction of tenofovir 300 mg daily (M0) and at 3 months (M3) and 6 months (M6), thereafter. Phosphate, creatinine, glucose and protein levels were determined in plasma and urine. The ratio of maximal reabsorption capacity (TmPO4)/glomerular filtration rate (GFR) was determined by using the normogramm of Walton and Bijvoet. RESULTS: In the transversal study, 26% of patients had hypophosphatemia (<0.84 mmol/l) while 47% of patients had a decreased TmPO4/GFR (<0.8 mmol/l). In the prospective study, baseline prevalence of hypophosphatemia (<0.84 mmol/l) and decreased TmPO4/GFR (<0.8mmol/l) was 31 and 41%, respectively. Three and 6 months after starting tenofovir, there is no significant change in mean phosphate levels (M0:0.91 mmol/l, M3:0.97 mmol/l, M6:0.98 mmol/l) and mean TmPO4/GFR (M0:0.80 mmol/l, M3:0.88 mmol/l, M6:0.84 mmol/l). Moreover, prevalence of hypophosphatemia (M3:28%, M6:28%) and decreased TmPO4/GFR (M3:41%, M6:45%) remained stable. CONCLUSION: Hypophosphatemia linked to a decreased proximal tubular reabsorption was frequently observed in HIV-positive adults independently of the use of tenofovir. In this preliminary study, no worsening effect on phosphatemia and tubular phosphate reabsorption was observed 6 months after introduction of tenofovir in treatment experienced patients.

CXCR4 overexpression during the course of HIV-1 infection correlates with the emergence of X4 strains.

The factors that determine the emergence of X4 isolates in some HIV-1-infected subjects are unknown. As the level of expression of CXCR4 could favor an R5 to X4 switch, quantitative flow cytometry was used to measure CXCR4 density on CD4 T cells in 200 HIV-1-positive adults, and this was compared with CD4 counts, interleukin-7 (IL-7), and RANTES (regulated on activation, normal T expressed and secreted) plasma levels and the R5/X4 virus phenotype. CD4 T-cell surface CXCR4 densities were increased in infected subjects and inversely correlated with CD4 T-cell count (r=-0.548, P<0.001). Yet, in vitro infection with either R5 or X4 strains and in vivo increases in viral load following interruption of antiretroviral treatment did not induce CXCR4 overexpression. The plasma levels of IL-7 and RANTES, 2 cytokines able to induce CXCR4 expression, did not correlate with CXCR4 density. Finally, higher CXCR4 densities were observed in patients harboring X4 strains (3300, 95% CI 2431-4169 CXCR4 molecules per cell) than in patients harboring only R5 strains (2406, 95% CI 2135-2677, P=0.027). These data suggest that CXCR4 overexpression during the course of the disease in some patients could favor the emergence of X4 strains.

T-Cell surface CCR5 density is not correlated with hepatitis severity in hepatitis C virus/HIV-coinfected individuals: implications for the therapeutic use of CCR5 antagonists.

CCR5 antagonists represent promising anti-HIV agents. Yet, if the CCR5 chemokine receptor plays a positive role in hepatitis C virus (HCV) infection, CCR5 antagonists might be contraindicated in HCV/HIV-coinfected subjects. Therefore, we tested the hypothesis that the level of T-cell surface CCR5 expression, which might determine the intensity of HCV-specific T-cell recruitment into the liver, and thereby the efficiency of the anti-HCV response, could determine HCV disease evolution. For this purpose, we compared CCR5 density, measured by quantitative flow cytometry at the surface of nonactivated (human leukocyte antigen-D-related [HLA-DR]-) T cells of 51 HCV/HIV patients, with HCV load, serum aminotransferase levels, and liver histology (inflammatory activity, fibrosis, and rate of fibrosis progression). DR-CD4+ T-cell surface CCR5 density, which correlated with DR-CD8+ T-cell surface CCR5 density and was stable over time in HCV/HIV-coinfected individuals, did not correlate with any of the biologic parameters of HCV infection analyzed and was not linked to the capacity to clear the virus. In conclusion, we failed to demonstrate any impact of interindividual variability in T-cell surface CCR5 density on HCV infection, which would have argued against the use of CCR5 antagonists in HIV/HCV-coinfected subjects.

Detection and enumeration of circulating HIV-1-specific memory B cells in HIV-1-infected patients.

Memory B cells are long-living cells that circulate throughout the body and differentiate into plasma cells after stimulation by antigens, cytokines, and direct cell-to-cell interaction in lymphoid tissues. For HIV-1-infected patients, we assessed whether in vitro polyclonal B cell activation that induces immunoglobulin secreting cells (SCs) also generates HIV-1-specific resting B cells to synthesize antibodies specific to HIV-1. To this end, highly purified B cells from 10 HIV-1-untreated patients were cultured with or without mouse fibroblastic cells expressing the CD40 ligand in the presence of IL-2 and IL-10. The percentage of immunoglobulin SCs we obtained by using the B cell-CD40L stimulation system was equal to 55% to 98% of the circulating memory B cells. Moreover, the anti-HIV-1 IgG, IgA, or IgM antibody SCs represented 1 x 10-2 to 1 x 10-3 of the total immunoglobulin SCs. The anti-HIV-1-specific antibodies detected in cell culture supernatants were directed to gag-, pol-, and env-encoded viral proteins. We found that in AIDS patients, HIV-1-specific resting memory B cells circulate in the blood and can be quantified by their anti-HIV-1 antibody secretion after strong B cell polyclonal stimulation.

Reasons for early abacavir discontinuation in HIV-infected patients.

OBJECTIVE: To determine incidence of and reasons for discontinuation of abacavir within the first 6 months of therapy. METHODS: Retrospective study performed in the cohort of HIV-infected adults who started abacavir in a medical unit between 1997 and December 2000. All adverse drug reactions (ADRs) (especially hypersensitivity) observed in this cohort were reported. The association between drugs and complications were evaluated, using the French method to assess unexpected and toxic drug reactions. According to the variables studied, statistical analysis was performed using the chi2 test, Fisher's exact test, Mann-Whitney, Wilcoxon, or Kruskal-Wallis tests. RESULTS: All 331 patients treated with abacavir during this time period were included in this study. Early discontinuation of abacavir was observed in 34.1% of patients, the main reasons being adverse effects (20.8%), virologic failure (3.3%), drug holidays (2.7%), poor adherence (2.7%), and death (1.8%). Adverse effects were mostly represented by hypersensitivity reactions. After retrospective analysis, abacavir was stopped for likely hypersensitivity in 8.5% of patients, for doubtful hypersensitivity in 4.2%, and for other adverse effects in 8.1% of patients. CONCLUSIONS: This study shows that abacavir is mainly stopped during the first 6 months of therapy for ADRs. The rate of likely hypersensitivity reaction observed in this study (8.5%) is higher than that observed in clinical trials (5%). After retrospective evaluation, the causality assessment of abacavir is not always certain.