Early control of HIV replication in primary HIV-1 infection treated with antiretroviral drugs and pegylated IFN alpha: results from the Primoferon A (ANRS 086) Study

No Effect of Pegylated Interferon-α on Total HIV-1 DNA Load in HIV-1/HCV Coinfected Patients

Pegylated interferon-alpha (pIFN-α) is suggested to lower human immunodeficiency virus type-1 (HIV-1) DNA load in antiretroviral therapy (ART)-treated patients. We studied kinetics of HIV-1 DNA levels in 40 HIV-1/hepatitis C virus (HCV) coinfected patients, treated with pIFN-α for HCV and categorized into 3 groups according to start of ART: chronic HIV-1 infection (n = 22), acute HIV-1 infection (n = 8), no-ART (n = 10). Total HIV-1 DNA levels in 247 peripheral blood mononuclear cell samples were stable before, during, and after pIFN-α treatment in all groups. Our results question the benefit of pIFN-α as an immunotherapeutic agent for reducing the HIV-1 reservoir.

NK Response Correlates with HIV Decrease in Pegylated IFN-α2a-Treated Antiretroviral Therapy-Suppressed Subjects

We previously reported that pegylated IFN-α2a (Peg-IFN-α2a) added to antiretroviral therapy (ART)-suppressed, HIV-infected subjects resulted in plasma HIV control and integrated HIV DNA decrease. We now evaluated whether innate NK cell activity or PBMC transcriptional profiles were associated with decreases in HIV measures. Human peripheral blood was analyzed prior to Peg-IFN-α2a administration (ART, baseline), after 5 wk of ART+Peg-IFN-α2a, and after 12 wk of Peg-IFN-α2a monotherapy (primary endpoint). After 5 wk of ART+Peg-IFN-α2a, immune subset frequencies were preserved, and induction of IFN-stimulated genes was noted in all subjects except for a subset in which the lack of IFN-stimulated gene induction was associated with increased expression of microRNAs. Viral control during Peg-IFN-α2a monotherapy was associated with 1) higher levels of NK cell activity and IFN-γ-induced protein 10 (IP-10) on ART (preimmunotherapy) and 2) downmodulation of NK cell KIR2DL1 and KIR2DL2/DL3 expression, transcriptional enrichment of expression of genes associated with NK cells in HIV controller subjects, and higher ex vivo IFN-α-induced NK cytotoxicity after 5 wk of ART+Peg-IFN-α2a. Integrated HIV DNA decline after immunotherapy was also associated with gene expression patterns indicative of cell-mediated activation and NK cytotoxicity. Overall, an increase in innate activity and NK cell cytotoxicity were identified as correlates of Peg-IFN-α2a-mediated HIV control.

Control of HIV infection by IFN-α: implications for latency and a cure

Viral infections, including HIV, trigger the production of type I interferons (IFNs), which in turn, activate a signalling cascade that ultimately culminates with the expression of anti-viral proteins. Mounting evidence suggests that type I IFNs, in particular IFN-α, play a pivotal role in limiting acute HIV infection. Highly active anti-retroviral treatment reduces viral load and increases life expectancy in HIV positive patients; however, it fails to fully eliminate latent HIV reservoirs. To revisit HIV as a curable disease, this article reviews a body of literature that highlights type I IFNs as mediators in the control of HIV infection, with particular focus on the anti-HIV restriction factors induced and/or activated by IFN-α. In addition, we discuss the relevance of type I IFN treatment in the context of HIV latency reversal, novel therapeutic intervention strategies and the potential for full HIV clearance.

Interferons and HIV Infection: The Good, the Bad, and the Ugly

Whether type I interferons (IFNs) hinder or facilitate HIV disease progression is controversial. Type I IFNs induce the production of restriction factors that protect against mucosal HIV/SIV acquisition and limit virus replication once systemic infection is established. However, type I IFNs also increase systemic immune activation, a predictor of poor CD4⁺ T-cell recovery and progression to AIDS, and facilitate production and recruitment of target CD4⁺ T cells. In addition, type I IFNs induce CD4⁺ T-cell apoptosis and limit antigen-specific CD4⁺ and CD8⁺ T-cell responses. The outcomes of type I IFN signaling may depend on the timing of IFN-stimulated gene upregulation relative to HIV exposure and infection, local versus systemic type I IFN-stimulated gene expression, and the subtype of type I IFN evaluated. To date, most interventional studies have evaluated IFNα2 administration largely in chronic HIV infection, and few have evaluated the effects on tissues or the HIV reservoir. Thus, whether the effect of type I IFN signaling on HIV disease is good, bad, or so complicated as to be ugly remains a topic of hot debate.

Update on antiretroviral treatment during primary HIV infection

Primary HIV-1 infection covers a period of around 12 weeks in which the virus disseminates from the initial site of infection into different tissues and organs. In this phase, viremia is very high and transmission of HIV is an important issue. Most guidelines recommend antiretroviral treatment in patients who are symptomatic, although the indication for treatment remains inconclusive in asymptomatic patients. In this article the authors review the main virological and immunological events during this early phase of infection, and discuss the arguments for and against antiretroviral treatment. Recommendations of different guidelines, the issue of the HIV transmission and transmission of resistance to antiretroviral drugs, as well as recently available information opening perspectives for functional cure in patients treated in very early steps of HIV infection are also discussed.

[Consensus Statement by GeSIDA/National AIDS Plan Secretariat on antiretroviral treatment in adults infected by the human immunodeficiency virus (Updated January 2013)]

OBJECTIVE

This consensus document is an update of combined antiretroviral therapy (cART) guidelines for HIV-1 infected adult patients.

METHODS

To formulate these recommendations a panel composed of members of the GeSIDA/National AIDS Plan Secretariat (Grupo de Estudio de Sida and the Secretaría del Plan Nacional sobre el Sida) reviewed the efficacy and safety advances in clinical trials, cohort and pharmacokinetic studies published in medical journals (PubMed and Embase) or presented in medical scientific meetings. The strength of the recommendations and the evidence which support them are based on a modification of the criteria of Infectious Diseases Society of America.

RESULTS

cART is recommended in patients with symptoms of HIV infection, in pregnant women, in serodiscordant couples with high risk of transmission, in hepatitisB co-infection requiring treatment, and in HIV nephropathy. cART is recommended in asymptomatic patients if CD4 is <500cells/μl. If CD4 are >500cells/μl cART should be considered in the case of chronic hepatitisC, cirrhosis, high cardiovascular risk, plasma viral load >100.000 copies/ml, proportion of CD4 cells <14%, neurocognitive deficits, and in people aged >55years. The objective of cART is to achieve an undetectable viral load. The first cART should include 2 reverse transcriptase inhibitors (RTI) nucleoside analogs and a third drug (a non-analog RTI, a ritonavir boosted protease inhibitor, or an integrase inhibitor). The panel has consensually selected some drug combinations, for the first cART and specific criteria for cART in acute HIV infection, in tuberculosis and other HIV related opportunistic infections, for the women and in pregnancy, in hepatitisB or C co-infection, in HIV-2 infection, and in post-exposure prophylaxis.

CONCLUSIONS

These new guidelines update previous recommendations related to first cART (when to begin and what drugs should be used), how to monitor, and what to do in case of viral failure or adverse drug reactions. cART specific criteria in comorbid patients and special situations are similarly updated.

Pathogenesis and treatment of HIV infection: the cellular, the immune system and the neuroendocrine systems perspective

Infections with HIV represent a great challenge for the development of strategies for an effective cure. The spectrum of diseases associated with HIV ranges from opportunistic infections and cancers to systemic physiological disorders like encephalopathy and neurocognitive impairment. A major progress in controlling HIV infection has been achieved by highly active antiretroviral therapy (HAART). However, HAART does neither eliminate the virus reservoirs in form of latently infected cells nor does it completely reconstitute immune reactivity and physiological status. Furthermore, the failure of the STEP vaccine trial and the only marginal efficacies of the RV144 trial together suggest that the causal relationships between the complex sets of viral and immunological processes that contribute to protection or disease pathogenesis are still poorly understood. Here, we provide an up-to-date overview of HIV-host interactions at the cellular, the immune system and the neuroendocrine systems level. Only by integrating this multi-level knowledge one will be able to handle the systems complexity and develop new methodologies of analysis and prediction for a functional restoration of the immune system and the health of the infected host.

IFN-α treatment inhibits acute Friend retrovirus replication primarily through the antiviral effector molecule Apobec3

Therapeutic administration of IFN-α in clinical trials significantly reduced HIV-1 plasma viral load and human T-lymphotropic virus type I proviral load in infected patients. The mechanism may involve the concerted action of multiple antiretroviral effectors collectively known as "restriction factors," which could vary in relative importance according to the magnitude of transcriptional induction. However, direct genetic approaches to identify the relevant IFN-α restriction factors will not be feasible in humans in vivo. Meanwhile, mice encode an analogous set of restriction factor genes and could be used to obtain insights on how IFN-α could inhibit retroviruses in vivo. As expected, IFN-α treatment of mice significantly upregulated the transcription of multiple restriction factors including Tetherin/BST2, SAMHD1, Viperin, ISG15, OAS1, and IFITM3. However, a dominant antiretroviral factor, Apobec3, was only minimally induced. To determine whether Apobec3 was necessary for direct IFN-α antiretroviral action in vivo, wild-type and Apobec3-deficient mice were infected with Friend retrovirus, then treated with IFN-α. Treatment of infected wild-type mice with IFN-α significantly reduced acute plasma viral load 28-fold, splenic proviral load 5-fold, bone marrow proviral load 14-fold, and infected bone marrow cells 7-fold, but no inhibition was observed in Apobec3-deficient mice. These findings reveal that IFN-α inhibits acute Friend retrovirus infection primarily through the antiviral effector Apobec3 in vivo, demonstrate that transcriptional induction levels did not predict the mechanism of IFN-α-mediated control, and highlight the potential of the human APOBEC3 proteins as therapeutic targets against pathogenic retrovirus infections.

HIV downregulates interferon-stimulated genes in primary macrophages

HIV is able to outpace the innate immune response, including that mediated by interferon (IFN), to establish a productive infection. Primary macrophages, however, may be protected from HIV infection by treatment with type I IFN before virus exposure. The ability of HIV to modulate the type I IFN-mediated innate immune response when it encounters a cell that has already been exposed to IFN remains poorly defined. The optimal pretreatment time (12 h) and the most potent HIV-inhibitors (e.g., IFN-α2 and -ω) were identified to investigate the ability of HIV to modulate an established type I IFN response. Gene expression at the level of the entire transcriptome was then compared between primary macrophages treated with type I IFNs, as opposed to treated with IFNs and then infected with HIV. Although HIV was not able to establish a robust infection, the virus was able to downregulate a number of IFN-stimulated genes (ISGs) with a fold change greater than 1.5 (i.e., AXL, IFI27, IFI44, IFI44L, ISG15, OAS1, OAS3, and XAF1). The downregulation of OAS1 by the presence of HIV was confirmed by real-time quantitative polymerase chain reaction. In conclusion, even though HIV replication is significantly inhibited by IFN pretreatment, the virus is able to downregulate the transcription of known antiviral ISGs (e.g., IFI44, ISG15, and OAS1).

Continuous versus intermittent treatment strategies during primary HIV-1 infection: the randomized ANRS INTERPRIM Trial

OBJECTIVES

The ANRS-112 INTERPRIM trial assessed whether fixed-cycles of antiretroviral treatment interruption (ART-STI) combined or not with pegylated interferon alpha-2b (peg-IFN) could lower viral load and achieve a healthier immune system in patients diagnosed during primary HIV-1-infection (PHI).

DESIGN AND METHODS

Patients were randomized to receive either continuous ART (cART) during 72 weeks, or cART during 36 weeks followed by three ART-STIs, or the same ART-STIs associated with peg-IFN during the first 14 weeks and each interruption (ART-STI-IFN). Treatment was stopped at week 72. Final evaluation was based on plasma HIV-RNA level 6 months after the last treatment interruption.

RESULTS

Eighty-seven percent of patients achieved undetectable HIV-RNA at week 32, with no deleterious impact of sequential treatment interruptions (STIs). Viral rebounds during interruptions were lower in the ART-STI-IFN than in the ART-STI group and during the second and third interruptions compared with the first one. However, HIV-RNA levels, CD4 T-cell counts and CD4 T/CD8 T ratios were similar between groups after the 6-month interruption, with a persistent effect on CD4 T cells and total cell-associated HIV-DNA levels. Predictive factors of virological outcome were HIV-RNA and HIV-DNA levels at PHI and HIV-DNA levels at treatment interruption. HIV-specific responses did not differ between strategies and were not associated with outcome. Forty-eight percent of patients experienced treatment resumption during long-term follow-up without difference between groups.

CONCLUSION

When initiated during PHI, STIs associated or not with IFN did not result in a different outcome as compared to cART. All regimens showed a high response rate and a sustained immunological benefit after cessation.

Soluble mediators of inflammation in HIV and their implications for therapeutics and vaccine development

From early in the HIV epidemic it was appreciated that many inflammatory markers such as neopterin and TNF-α were elevated in patients with AIDS. With the advent of modern technology able to measure a broad array of cytokines, we now know that from the earliest points of infection HIV induces a cytokine storm. This review will focus on how cytokines are disturbed in HIV infection and will explore potential therapeutic uses of cytokines. These factors can be used directly as therapy during HIV infection, either to suppress viral replication or prevent deleterious immune effects of infection, such as CD4+ T cell depletion. Cytokines also show great promise as adjuvants in the development of HIV vaccines, which would be critical for the eventual control of the epidemic.

[Consensus document of Gesida and Spanish Secretariat for the National Plan on AIDS (SPNS) regarding combined antiretroviral treatment in adults infected by the human immunodeficiency virus (January 2012)]

This consensus document has been prepared by a panel consisting of members of the AIDS Study Group (Gesida) and the Spanish Secretariat for the National Plan on AIDS (SPNS) after reviewing the efficacy and safety results of clinical trials, cohort and pharmacokinetic studies published in medical journals, or presented in medical scientific meetings. Gesida has prepared an objective and structured method to prioritise combined antiretroviral treatment (cART) in naïve patients. Recommendations strength (A, B, C) and the evidence which supports them (I, II, III) are based on a modification of the Infectious Diseases Society of America criteria. The current antiretroviral treatment (ART) of choice for chronic HIV infection is the combination of three drugs. ART is recommended in patients with symptomatic HIV infection, in pregnancy, in serodiscordant couples with high transmission risk, hepatitis B fulfilling treatment criteria, and HIV nephropathy. Guidelines on ART treatment in patients with concurrent diagnosis of HIV infection and an opportunistic type C infection are included. In asymptomatic patients ART is recommended on the basis of CD4 lymphocyte counts, plasma viral load and patient co-morbidities, as follows: 1) therapy should be started in patients with CD4 counts <350 cells/μL; 2) when CD4 counts are between 350 and 500 cells/μL, therapy will be recommended and only delayed if patient is reluctant to take it, the CD4 are stabilised, and the plasma viral load is low; 3) therapy could be deferred when CD4 counts are above 500 cells/μL, but should be considered in cases of cirrhosis, chronic hepatitis C, high cardiovascular risk, plasma viral load >10(5) copies/mL, proportion of CD4 cells <14%, and in people aged >55 years. ART should include 2 reverse transcriptase inhibitors nucleoside analogues and a third drug (non-analogue reverse transcriptase inhibitor, ritonavir boosted protease inhibitor or integrase inhibitor). The panel has consensually selected and given priority to using the Gesida score for some drug combinations, some of them co-formulated. The objective of ART is to achieve an undetectable viral load. Adherence to therapy plays an essential role in maintaining antiviral response. Therapeutic options are limited after ART failures, but an undetectable viral load may be possible nowadays. Adverse events are a fading problem of ART. Guidelines in acute HIV infection, in women, in pregnancy, and to prevent mother-to-child transmission and pre- and post-exposition prophylaxis are commented upon. Management of hepatitis B or C co-infection, other co-morbidities, and the characteristics of ART in HIV-2 infection are included.

Interferon-alpha administration enhances CD8+ T cell activation in HIV infection

Background

Type I interferons play important roles in innate immune defense. In HIV infection, type I interferons may delay disease progression by inhibiting viral replication while at the same time accelerating disease progression by contributing to chronic immune activation.

Methods

To investigate the effects of type I interferons in HIV-infection, we obtained cryopreserved peripheral blood mononuclear cell samples from 10 subjects who participated in AIDS Clinical Trials Group Study 5192, a trial investigating the activity of systemic administration of IFNα for twelve weeks to patients with untreated HIV infection. Using flow cytometry, we examined changes in cell cycle status and expression of activation antigens by circulating T cells and their maturation subsets before, during and after IFNα treatment.

Results

The proportion of CD38+HLA-DR+CD8+ T cells increased from a mean of 11.7% at baseline to 24.1% after twelve weeks of interferon treatment (p = 0.006). These frequencies dropped to an average of 20.1% six weeks after the end of treatment. In contrast to CD8+ T cells, the frequencies of activated CD4+ T cells did not change with administration of type I interferon (mean percentage of CD38+DR+ cells = 2.62% at baseline and 2.17% after 12 weeks of interferon therapy). As plasma HIV levels fell with interferon therapy, this was correlated with a “paradoxical” increase in CD8+ T cell activation (p<0.001).

Conclusion

Administration of type I interferon increased expression of the activation markers CD38 and HLA DR on CD8+ T cells but not on CD4+ T cells of HIV+ persons. These observations suggest that type I interferons may contribute to the high levels of CD8+ T cell activation that occur during HIV infection.

[AIDS Study Group/Spanish AIDS Plan consensus document on antiretroviral therapy in adults with human immunodeficiency virus infection (updated January 2010)]

OBJECTIVE

This consensus document is an update of antiretroviral therapy recommendations for adult patients with human immunodeficiency virus infection.

METHODS

To formulate these recommendations a panel made up of members of the Grupo de Estudio de Sida (Gesida, AIDS Study Group) and the Plan Nacional sobre el Sida (PNS, Spanish AIDS Plan) reviewed the advances in the current understanding of the pathophysiology of human immunodeficiency virus (HIV) infection, the efficacy and safety of clinical trials, and cohort and pharmacokinetic studies published in biomedical journals or presented at scientific meetings. Three levels of evidence were defined according to the data source: randomized studies (level A), cohort or case-control studies (level B), and expert opinion (level C). The decision to recommend, consider or not to recommend ART was established in each situation.

RESULTS

Currently, the treatment of choice for chronic HIV infection is the combination of three drugs of two different classes, including 2 nucleosides or nucleotide analogs (NRTI) plus 1 non-nucleoside (NNRTI) or 1 boosted protease inhibitor (PI/r), but other combinations are possible. Initiation of ART is recommended in patients with symptomatic HIV infection. In asymptomatic patients, initiation of ART is recommended on the basis of CD4 lymphocyte counts, plasma viral load and patient co-morbidities, as follows: 1) therapy should be started in patients with CD4 counts below 350 cells/microl; 2) When CD4 counts are between 350 and 500 cells/microl, therapy should be started in case of cirrhosis, chronic hepatitis C, high cardiovascular risk, HIV nephropathy, HIV viral load above 100,000 copies/ml, proportion of CD4 cells under 14%, and in people aged over 55; 3) Therapy should be deferred when CD4 are above 500 cells/microl, but could be considered if any of previous considerations concurs. Treatment should be initiated in case of hepatitis B requiring treatment and should be considered for reduce sexual transmission. The objective of ART is to achieve an undetectable viral load. Adherence to therapy plays an essential role in maintaining antiviral response. Therapeutic options are limited after ART failures but undetectable viral loads maybe possible with the new drugs even in highly drug experienced patients. Genotype studies are useful in these situations. Drug toxicity of ART therapy is losing importance as benefits exceed adverse effects. Criteria for antiretroviral treatment in acute infection, pregnancy and post-exposure prophylaxis are mentioned as well as the management of HIV co-infection with hepatitis B or C.

CONCLUSIONS

CD4 cells counts, viral load and patient co-morbidities are the most important reference factors to consider when initiating ART in asymptomatic patients. The large number of available drugs, the increased sensitivity of tests to monitor viral load, and the ability to determine viral resistance is leading to a more individualized therapy approach in order to achieve undetectable viral load under any circumstances.

Safety, tolerability, and mechanisms of antiretroviral activity of pegylated interferon Alfa-2a in HIV-1-monoinfected participants: a phase II clinical trial

BACKGROUND

To our knowledge, the antiviral activity of pegylated interferon alfa-2a has not been studied in participants with untreated human immunodeficiency virus type 1 (HIV-1) infection but without chronic hepatitis C virus (HCV) infection.

METHODS

Untreated HIV-1-infected volunteers without HCV infection received 180 microg of pegylated interferon alfa-2a weekly for 12 weeks. Changes in plasma HIV-1 RNA load, CD4(+) T cell counts, pharmacokinetics, pharmacodynamic measurements of 2',5'-oligoadenylate synthetase (OAS) activity, and induction levels of interferon-inducible genes (IFIGs) were measured. Nonparametric statistical analysis was performed.

RESULTS

Eleven participants completed 12 weeks of therapy. The median plasma viral load decrease and change in CD4(+) T cell counts at week 12 were 0.61 log(10) copies/mL (90% confidence interval [CI], 0.20-1.18 log(10) copies/mL) and -44 cells/microL (90% CI, -95 to 85 cells/microL), respectively. There was no correlation between plasma viral load decreases and concurrent pegylated interferon plasma concentrations. However, participants with larger increases in OAS level exhibited greater decreases in plasma viral load at weeks 1 and 2 (r = -0.75 [90% CI, -0.93 to -0.28] and r = -0.61 [90% CI, -0.87 to -0.09], respectively; estimated Spearman rank correlation). Participants with higher baseline IFIG levels had smaller week 12 decreases in plasma viral load (0.66 log(10) copies/mL [90% CI, 0.06-0.91 log(10) copies/mL]), whereas those with larger IFIG induction levels exhibited larger decreases in plasma viral load (-0.74 log(10) copies/mL [90% CI, -0.93 to -0.21 log(10) copies/mL]).

CONCLUSION

Pegylated interferon alfa-2a was well tolerated and exhibited statistically significant anti-HIV-1 activity in HIV-1-monoinfected patients. The anti-HIV-1 effect correlated with OAS protein levels (weeks 1 and 2) and IFIG induction levels (week 12) but not with pegylated interferon concentrations.

Interferons and their use in persistent viral infections

In 2007, the world celebrated the 50th anniversary of the discovery of interferon (IFN) by Isaacs and Lindenmann. Subsequently, the IFN-alpha gene was cloned, fully sequenced and IFN-alpha was produced in recombinant form. Recombinant IFN-alpha is now used as the basis for treatment of chronic hepatitis C virus infection and can also be used to treat certain forms of chronic hepatitis B virus infections. IFNs have also been used in other viral infections, although with less success. The antiviral mechanisms of IFNs are reviewed in this chapter as well as the utility of IFNs in the treatment of persistent viral infections.

Pegylated interferon-alpha 2a treatment of chronic SIV-infected macaques

BACKGROUND

In vitro and clinical observations in HIV-infected patients receiving interferon alpha therapy have shown a reduction in HIV loads. Limited investigations have explored the innate or adaptive immune responses of IFN-alpha on SIV replication in vivo.

METHODS

Seven chronically infected rhesus macaques were given pegylated IFN-alpha 2a (n = four) or saline (n = three) injections once weekly for 14 weeks. Weekly peripheral blood samples were taken for safety parameters, viral load determinations, and measurements of innate and adaptive immune responses.

RESULTS

Pharmacokinetic measurements demonstrated therapeutic peg-IFN-alpha levels for the initial period of therapy and IFN-alpha inducible antiviral molecules were increased sporadically in the PBMC mRNA of the treatment group. Despite the demonstrable effect of the IFN-alpha injections, the treatment had no effect on plasma viral RNA levels.

CONCLUSIONS

This work demonstrates that while short term IFN-alpha therapy induces innate antiviral immunity, it does not dramatically enhance or suppress viral replication. However, studies in the SIV model to determine therapeutic potential of chronic IFN-alpha therapy for the treatment of HIV will require macaque specific cytokines.

Stimulation of the primary anti-HIV antibody response by IFN-alpha in patients with acute HIV-1 infection

Type I IFNs are needed for the production of antiviral antibodies in mice; whether they also stimulate primary antibody responses in vivo during human viral infections is unknown. This was assessed in patients acutely infected with HIV-1 and treated with IFN-alpha2b. Patients with acute HIV-1 infection were randomized to receive antiretroviral therapy alone (Group A, n=60) or combined for 14 weeks with pegylated-IFN-alpha2b (Group B, n=30). Emergence of anti-HIV antibodies was monitored during 32 weeks by Western blot (WB) analyses of serum samples. IFN-alpha2b treatment stimulated the production of anti-HIV antibodies. On Week 32, 19 weeks after the last IFN-alpha2b administration, there were 8.5 (6.5-10.0) HIV WB bands (median, interquartile range) in Group B and 7.0 (5.0-10.0) bands in Group A (P=0.054), and band intensities were stronger in Group B (P<0.05 for p18, p24, p34, p40, and p55 HIV antigens). IFN-alpha2b treatment also increased circulating concentrations of the B cell-activating factor of the TNF family (P<0.001) and ex vivo production of IL-12 (P<0.05), reflecting its effect on innate immune cells. Withdrawal of antiretroviral treatment on Week 36 resulted in a lower rebound of HIV replication in Group B than in Group A (P<0.05). Therefore, type I IFNs stimulate the emerging anti-HIV immune response in patients with acute HIV-1 infection, resulting in an improved control of HIV replication. Type I IFNs are thus critical in the development of efficient antiviral immune responses in humans, including the production of antiviral antibodies.

Role for plasmacytoid dendritic cells in anti-HIV innate immunity

The role of plasmacytoid dendritic cells (pDC) in anti-HIV immunity is mostly represented by the production of type I IFN in response to HIV infection in vitro and in vivo. This production is decreased in HIV-1 infected patients at the time of primary infection and during chronic disease in association with progression of disease. Circulating pDC counts are decreased concomitantly with type I IFN, and both factors correlate inversely overall with viral loads and positively with CD4+ T-cell counts. These parameters might be used in clinical immunology to monitor treatment and as predictive factors of immune control of HIV-1 replication to help decide whether to interrupt antiretroviral treatment. They may be related to control of HIV replication as well as to pathogenesis of infection, perhaps in setting the balance between immunity or tolerance to the virus. A better understanding of these parameters is required while attempts to use IFN-alpha or ligands of Toll-like receptors found on pDC are being made.

Comparative effects of two type I interferons, human IFN-? and ovine IFN-? on indoleamine-2,3-dioxygenase in primary cultures of human macrophages

Type I interferons (IFNs) are widely used to treat viral diseases. Depressive symptoms and suicide attempts are common neuropsychiatric side-effects during treatment with type I IFNs. Activation of indoleamine-2,3-dioxygenase (IDO), the first and rate-limiting enzyme of the kynurenine pathway by IFNs, leads to an increase in tryptophan (Trp) catabolism. Low levels of Trp lead to decrease of serotonin synthesis, which is likely to be related to the depressive symptoms. Ovine type I interferon-tau (IFN-tau) has a more potent antiretroviral effect and is less toxic than human type I IFN-alpha. Effects of IFN-tau and IFN-alpha on IDO expression and activity in primary cultures of human macrophages were compared in parallel to those of IFN-gamma, considered as one of the most potent IDO inducer. We found that both IFN-alpha and IFN-tau were poor inducers of IDO compared with IFN-gamma. However, IDO activation was slightly and significantly lower with ovine IFN-tau than human IFN-alpha, suggesting that ovine IFN-tau might have a lower impact on serotoninergic pathway compared with human IFN-alpha.

Alpha interferon potently enhances the anti-human immunodeficiency virus type 1 activity of APOBEC3G in resting primary CD4 T cells

The interferon (IFN) system, including various IFNs and IFN-inducible gene products, is well known for its potent innate immunity against wide-range viruses. Recently, a family of cytidine deaminases, functioning as another innate immunity against retroviral infection, has been identified. However, its regulation remains largely unknown. In this report, we demonstrate that through a regular IFN-alpha/beta signal transduction pathway, IFN-alpha can significantly enhance the expression of apolipoprotein B mRNA-editing enzyme-catalytic polypeptide-like 3G (APOBEC3G) in human primary resting but not activated CD4 T cells and the amounts of APOBEC3G associated with a low molecular mass. Interestingly, short-time treatments of newly infected resting CD4 T cells with IFN-alpha will significantly inactivate human immunodeficiency virus type 1 (HIV-1) at its early stage. This inhibition can be counteracted by APOBEC3G-specific short interfering RNA, indicating that IFN-alpha-induced APOBEC3G plays a key role in mediating this anti-HIV-1 process. Our data suggest that APOBEC3G is also a member of the IFN system, at least in resting CD4 T cells. Given that the IFN-alpha/APOBEC3G pathway has potent anti-HIV-1 capability in resting CD4 T cells, augmentation of this innate immunity barrier could prevent residual HIV-1 replication in its native reservoir in the post-highly active antiretroviral therapy era.

Type I interferon production in HIV-infected patients

Type I IFNs display multiple biological effects. They have a strong antiviral action, not only directly but also indirectly through activation of the immune system. They may also have actions that are deleterious for the host. The cells that produce type I IFN are mostly plasmacytoid dendritic cells (pDC), but this depends on the viral stimulus. The migration and distribution of pDC into lymphoid organs, driven by chemokine interactions with their ligands, determines interaction with different cell types. In HIV infection, IFN production in vitro is impaired during primary infection and later in association with opportunistic infections. Circulating pDC numbers are decreased in parallel. These parameters may be used to help assess the prognosis of the disease and to monitor treatment.

Interferon-alpha differentially rescues CD4 and CD8 T cells from apoptosis in HIV infection

OBJECTIVE

To examine the effects of interferon-alpha (IFN-alpha) on T cell survival and activation in HIV infection.

DESIGN

The effects of IFN-alpha on spontaneous apoptosis and CD38 expression among T cell subsets were determined in vitro and studied in relation to CD4 cell counts, plasma HIV RNA levels and the age of the subjects.

METHODS

Peripheral blood mononuclear cells from 48 HIV-infected persons and 17 healthy donors were incubated in vitro overnight with or without the addition of IFN-alpha. Percentages of apoptotic cells (positive for annexin V) and CD38 cells were determined among T cell subsets.

RESULTS

IFN-alpha inhibited spontaneous apoptosis of CD4 and CD8 T lymphocytes. This protective activity was impaired in CD4 T cells from HIV-infected persons. The reduced protection of IFN-alpha among CD4 cells from HIV-infected persons was not related to the percentages of activated (CD38 or CD45RO+CD38+) cells. Surprisingly, IFN-alpha induced CD38 expression among CD8 T cells from HIV-infected persons, and the magnitude of this effect was directly related to circulating CD4 T cell count. The CD8 T cell subset that expressed CD38 in response to IFN-alpha was defined as CD28 negative, CD62 ligand (CD62L) intermediate/negative.

CONCLUSIONS

Heightened expression of IFN-alpha in HIV infection may contribute to the phenotypic activation state that characterizes chronic infection while a diminished responsiveness of CD4 T cells to the protective effect of this cytokine may contribute to differential survival of CD4 and CD8 T cells in HIV disease.

HIV-1 resistant strains acquired at the time of primary infection massively fuel the cellular reservoir and persist for lengthy periods of time

OBJECTIVE

Characterization of the early establishment of the viral reservoir in patients acquiring resistant strains at primary HIV-1 infection (PHI), and longitudinal analysis of resistance mutations in circulating virions and intracellular HIV strains.

PATIENTS AND METHODS

Drug-resistance was compared between HIV RNA and peripheral blood mononuclear cell (PBMC)-HIV DNA at the time of PHI in 44 patients enrolled in the Primo Cohort and harbouring plasma HIV-1 resistant to at least one antiretroviral drug. Longitudinal monitoring of viral load and resistance genotype was performed in plasma-HIV RNA and PBMC HIV DNA for at least 24 months in a subset of 10 patients. Phylogenetic analysis of HIV DNA protease gene clones was used to explore the diversity of quasi-species at baseline.

RESULTS

Baseline resistance profile was identical in paired HIV RNA and PBMC HIV DNA for all 44 patients. All resistance-associated mutations persisted in plasma and PBMC over 2 years in the five untreated patients. Of the five patients started on empirical HAART, two achieved undetectable HIV RNA at month 6, with long-term persistence of archived drug-resistance mutations in PBMC HIV DNA. Virological failure was observed in the other three patients, resulting in the accumulation of additional drug-resistance mutations in HIV RNA and HIV DNA for two of them. Phylogenetic analysis of HIV DNA clones showed highly homogenous and exclusively resistant quasi-species in the cellular reservoir at baseline.

CONCLUSION

HIV resistant strains acquired at the time of PHI massively fuel the cellular reservoir, and their prolonged persistence is supported by the early expansion of a dominant homogenous and resistant viral population. Results in treated patients showed that classical empirical triple-combination may be suboptimal.

[Advances in the diagnosis and treatment of acute human immunodeficiency virus type 1 (HIV-1) infection]

According the WHO there are about 14,000 new HIV infections a day. However, in a few cases the diagnosis will be made in the acute phase of the disease. Acute HIV infection is the period between infection with the virus and complete seroconversion, defined by a positive Western blot test. This period lasts approximately 30 days and most patients (40-90%) have mild clinical manifestations (fever, rash, pharyngitis, mucosal ulcers, among others) for 2 weeks which, because they are nonspecific, can be confused with other community-acquired infections. Microbiological diagnosis is based on the absence of serum antibodies (negative ELISA test) together with a positive HIV viral load in plasma (> 10,000 copies/ml). Diagnosis of acute HIV infection is important for several reasons: firstly, from the epidemiological point of view, this is the period with the highest rates of HIV transmission and identification of new HIV infections reveals the growth of the epidemic and the transmission rates of resistant HIV strains, which in Spain is about 10%; secondly, from the immunopathological point of view, this period provides a unique opportunity to study the virological, immunological and genetic mechanisms that play a role in the transmission and pathogenesis of this disease; and thirdly, therapeutically, starting antiretroviral therapy during this phase could alter the natural history of the disease. However, this is a controversial issue and currently most guidelines recommend treatment only if these patients can be included in clinical trials or if they show lasting or severe clinical manifestations.

Therapeutic Interventions for HIV Infection and Chronic Viral Hepatitis

Combination antiretroviral therapy reduces overall and liver-specific morbidity and mortality in coinfection with human immunodeficiency virus (HIV) and hepatitis C virus (HCV) and represents the most beneficial pharmaceutical treatment intervention for most coinfected patients. Antiviral therapy for HCV infection is potentially organ- and life-saving but, in general, should be reserved for patients who achieve suppression of HIV RNA and immune restoration from combination antiretroviral therapy or for patients with nadir CD4+ T lymphocyte levels of >350 cells/microL. Safe and virologically active treatment of coinfection with HIV and hepatitis B virus can be concurrently achieved by the use of combination antiretroviral therapy regimens containing lamivudine and/or tenofovir.

Therapies for HIV and viral hepatitis coinfection

The natural history of chronic viral hepatitis is altered by HIV coinfection. Liver fibrosis rates and clinical features of liver disease develop more rapidly. Although HIV-hepatitis C virus coinfected subjects may progress more rapidly to AIDS, this is probably explained by comorbid illness, substance abuse and socioeconomic circumstances. Safe and virologically active treatment of HIV-hepatitis B virus coinfection can be concurrently achieved by the use of highly active antiretroviral therapy regimens containing lamivudine and/or tenofovir. In most cases, highly active antiretroviral therapy represents the most beneficial initial pharmaceutical intervention for HIV-hepatitisC virus coinfection. HepatitisC virus antiviral therapy should, in most cases, be reserved for those achieving HIV RNA suppression and immune restoration from highly active antiretroviral therapy or with nadir CD4 T-lymphocytes above 350 cells/microl.

Dendritic cells cross-present HIV antigens from live as well as apoptotic infected CD4+ T lymphocytes

A better understanding of the antigen presentation pathways that lead to CD8(+) T cell recognition of HIV epitopes in vivo is needed to achieve better immune control of HIV replication. Here, we show that cross-presentation of very small amounts of HIV proteins from apoptotic infected CD4(+) T lymphocytes by dendritic cells to CD8(+) T cells is much more efficient than other known HIV presentation pathways, i.e., direct presentation of infectious virus or cross-presentation of defective virus. Unexpectedly, dendritic cells also take up actively antigens into endosomes from live infected CD4(+) T lymphocytes and cross-present them as efficiently as antigens derived from apoptotic infected cells. Moreover, live infected CD4(+) T cells costimulate cross-presenting dendritic cells in the process. Therefore, dendritic cells can present very small amounts of viral proteins from infected T cells either after apoptosis, which is frequent during HIV infection, or not. Thus, if HIV expression is transiently induced while costimulation is enhanced (for instance after IL-2 and IFNalpha immune therapy), this HIV antigen presentation pathway could be exploited to eradicate latently infected reservoirs, which are poorly recognized by patients' immune systems.

HIV type 1-infected dendritic cells induce apoptotic death in infected and uninfected primary CD4 T lymphocytes

In addition to their essential role in adaptive immunity, dendritic cells (DCs) participate in innate immunity. In the context of measles virus (MV) or cytomegalovirus infections, they develop cytotoxic functions that may contribute in vivo to the elimination of virus-infected cells, but that also kill infected and noninfected T lymphocytes. Because the human immunodeficiency virus (HIV) induces T cell depletion through mechanisms that are still obscure, we investigated its ability to trigger DC cytotoxicity. When incubated with HIV, monocyte-derived DCs induced apoptosis in MDA-231 cells, which are sensitive to MV-induced DC cytotoxicity, and in uninfected as well as HIV-infected H9 CD4+ T cell lines. This apoptosis was inhibited by a mixture of FasL, TRAIL, TNF-alpha, and TWEAK inhibitors. Indeed, HIV infection induced or enhanced sensitivity to TRAIL, TNF-alpha, and TWEAK in H9 cells. Moreover, dendritic cells incubated with HIV-1 BAL or a wildtype HIV-1 isolate induced apoptosis in autologous primary CD4+ T lymphocytes, infected or not with a wild-type HIV-1 isolate. Therefore, induction of DC cytotoxicity by HIV may be relevant to in vivo HIV infection. Induction of cytotoxicity in DCs by HIV might contribute to HIV-associated T cell depletion through induction of apoptosis, especially in the early stages of infection. It may also contribute to elimination of infected cells in vivo, thereby enhancing cross-presentation of HIV by DCs. Therefore this new cytotoxic function of DCs may play an important role in innate and adaptive immunity during HIV infection.

Anti-human immunodeficiency virus activity of tau interferon in human macrophages: involvement of cellular factors and beta-chemokines

Tau interferon (IFN-tau) is a noncytotoxic type I IFN responsible for maternal recognition of the fetus in ruminants. IFN-tau inhibits human immunodeficiency virus (HIV) replication more strongly than human IFN-alpha, particularly in human monocyte-derived macrophages. In this study performed in human macrophages, IFN-tau efficiently inhibited the early steps of the biological cycle of HIV, decreasing intracellular HIV RNA and inhibiting the initiation of the reverse transcription of viral RNA into proviral DNA. Two mechanisms induced by IFN-tau treatment in macrophages may account for this inhibition: (i) the synthesis of the cellular antiviral factors such as 2',5'-oligoadenylate synthetase/RNase L and MxA protein and (ii) an increased production of MIP-1alpha, MIP-1beta, and RANTES, which are natural ligands of CCR5, the principal coreceptor of HIV on macrophages. Our results suggest that IFN-tau induces the same antiviral pathways in macrophages as other type I IFNs but without associated toxicity.

Impact of 5 years of maximally successful highly active antiretroviral therapy on CD4 cell count and HIV-1 DNA level

OBJECTIVES

To evaluate the impact on CD4 cell count and HIV-1 DNA level in peripheral blood mononuclear cells (PBMC) of long-term highly active antiretroviral therapy (HAART) in the setting of maximal success, i.e., constant plasma HIV-1 RNA load suppression.

DESIGN

Retrospective analysis of patients selected for a constantly undetectable plasma HIV-1 RNA load since HAART initiation.

METHODS

HIV-1 DNA was measured in PBMC using a real-time polymerase chain reaction assay. Loess estimates and regression analysis were used for modelling the variations of the CD4 cell count and HIV DNA level over time.

RESULTS

The study included 41 patients chronically infected with HIV-1 who had been taking HAART for a median duration of 60.4 months and had an undetectable plasma HIV RNA load ever since the first 6 months of HAART; 25 were tested for HIV-1 DNA. The mean CD4 cell count increase was high during the first 18 months on therapy (168 x 10 cells/l per year), much lower afterwards (38 x 10 cells/l per year), independently of the baseline CD4 cell count. Most of the patients (73.2%) reached a CD4 cell count constantly > or = 400 x 10/l during follow-up. HIV-1 DNA showed a mean decrease of 0.48 log10 copies/10 PBMC during the first year, of 0.18 log10 copies/10 PBMC per year during the 2nd and 3rd years, but no significant decrease afterwards.

CONCLUSIONS

These results question the benefit of very long-term maintenance of HAART in terms of CD4 gain and HIV-1 DNA reduction.

Stable prevalence of genotypic drug resistance mutations but increase in non-B virus among patients with primary HIV-1 infection in France

OBJECTIVE

To evaluate the frequency of drug-resistant HIV-1 viral strains from patients presenting with primary infection in 1999-2000 and to survey the molecular epidemiology of these viruses circulating in France.

METHODS

Resistance mutations were detected by sequencing the reverse transcriptase and the protease genes in plasma samples from 249 individuals. Phylogenetic analysis was performed on the reverse transcriptase genes.

RESULTS

Ten per cent of patients [26/249; 95% confidence interval (CI) 7-15%] presented with virus mutations associated with resistance to at least one antiretroviral drug. The distribution of the resistance mutations was as follows: to nucleoside reverse transcriptase inhibitors in 19 (8%; 95% CI 5-12%) and to non-nucleoside reverse transcriptase inhibitors in 10 (4%; 95% CI 2-7%). Primary resistance mutations to protease inhibitors were detected in 14 (6%; 95% CI 3-9%). Twelve patients (5%; 95% CI 3-8%) presented with virus harbouring mutations associated with resistance to two or three classes of antiretroviral drugs. The median HIV RNA in plasma at enrollment was lower in patients with one or more drug resistance mutations than in patients with no mutations (5.05 log versus 5.47 log, P = 0.05). Phylogenetic analysis revealed that 19% (14-24%) of patients harboured HIV-1 non-B subtype strains; this proportion remained high when Caucasian patients only were considered (14%).

CONCLUSION

This study, performed within the French network on HIV-1 primary infection survey, revealed no change in the frequency of resistant viral strains over time, but showed an increasing prevalence of non-B subtypes overall and among Caucasian individuals.

Dendritic cells generated in the presence of granulocyte-macrophage colony-stimulating factor and IFN-alpha are potent inducers of HIV-specific CD8 T cells

OBJECTIVE

To investigate the ability of granulocyte-macrophage colony-stimulating factor (GM-CSF) and IFN-alpha to induce the differentiation of peripheral monocytes into dendritic cells (DC) and their ability to trigger an HIV-specific CD8 T-cell response.

METHODS

Monocytes isolated from both seronegative controls and HIV-infected individuals were differentiated into DC using GM-CSF with either IL-4 or IFN-alpha for 7 days. We assessed the phenotypic characteristics and IL-12 production by flow cytometry. The ability of DC to trigger CD8 T-cell responses was assessed by means of ELISpot and cytotoxicity assays. In addition, HIV-1-RNA levels were measured in culture supernatants.

RESULTS

Compared with control DC generated in the presence of GM-CSF and IL-4, DC generated in the presence of GM-CSF and IFN-alpha expressed higher levels of MHC class I molecules and produced similar or higher levels of IL-12 after CD40 ligation or Staphyloccus aureus Cowan stimulation. GM-CSF/IFN-alpha DC expressed low levels of CD4, CXCR4 and DC-SIGN and did not produce detectable virus during the differentiation period. Pulsed GM-CSF/IFN-alpha DC were found to prime CD8 T cells from HIV-negative controls to exert cytotoxic activity against target cells expressing HIV antigens. HIV peptide-pulsed GM-CSF/IFN-alpha DC promote specific IFN-gamma production by autologous CD8 T cells from HIV-seronegative donors. Furthermore, GM-CSF/IFN-alpha DC from HIV-seropositive patients efficiently present HIV peptides to autologous CD8 T lymphocytes.

CONCLUSION

GM-CSF and IFN-alpha allow the generation of DC with high CD8 T-cell stimulating abilities. Therefore, this strategy may represent a novel approach to therapeutic vaccination in HIV disease.

Cytokines as clinical adjuvants: how far are we?

In spite of the explosive growth in the discovery of cytokines and chemokines and in the understanding of their modes of action, clinical use of such agents as adjuvants has been primarily restricted to patients with cancer or chronic viral infections suffering from various levels of immune impairment and for whom the chemotherapeutic armamentarium, as well as other forms of immunotherapy, have been exhausted. This cautious approach has been justified by the difficulties inherent to the biological function and delivery of such pleiotropic agents, where doses needed to achieve the targeted immune enhancement often result in serious side effects, especially during systemic administration. In addition, optimization of dosages, administration schedules and biological effects in humans often do not correlate well with preclinical data derived from animal models. Nevertheless, novel preventive immunization strategies that target a precise type of immune response in immunocompetent individuals are expected to greatly benefit from the incorporation of cytokines and chemokines. This review provides an overview of current clinical administration of cytokines as well as a description of select Phase I testing of new agents designed to enhance immune defenses in vivo.

Effects of interferon-alpha on gene expression of chemokines and members of the tumour necrosis factor superfamily in HIV-infected patients

We examined the effect of interferon (IFN)-alpha on the expression of 375 genes relevant to inflammatory and immunological reactions in peripheral blood mononuclear cells (PBMC) from HIV-infected patients by cDNA expression array and real-time quantitative RT-PCR. Our main findings were: (i) IFN-alpha induced up-regulation of several genes in the tumour necrosis factor (TNF) superfamily including the ligands APRIL, FasL, TNF-alpha and TRAIL, with particularly enhancing effects on the latter in HIV-infected patients. (ii) While IFN-alpha markedly up-regulated the expression of anti-angionetic ELR- CXC-chemokines (e.g. MIG and IP-10), it suppressed the expression of angiogenic ELR+ CXC-chemokines (e.g. GRO-alpha, IL-8 and ENA-78), with similar patterns in both patients and controls. (iii) IFN-alpha induced a marked increase in gene expression of the HIV co-receptor CCR5 in both patients and controls. We suggest that these effects may contribute to both the therapeutic and toxic effects of IFN-alpha. Moreover, our findings underscore that the biological effects of IFN-alpha in HIV infection are complex and that the clinical net effects of IFN-alpha treatment may be difficult to predict. However, the potent enhancing effect of IFN-alpha on several pro-apoptotic genes in the TNF superfamily and the enhancing effect on CCR5 expression suggest a possible pathogenic role of IFN-alpha in the progression of HIV-related immunodeficiency and suggests caution in the therapeutic use of IFN-alpha in HIV-infected -individuals.

The relationship between simian immunodeficiency virus RNA levels and the mRNA levels of alpha/beta interferons (IFN-alpha/beta) and IFN-alpha/beta-inducible Mx in lymphoid tissues of rhesus macaques during acute and chronic infection

To define the role of alpha/beta interferons (IFN-alpha/beta) in simian immunodeficiency virus (SIV) infection, IFN-alpha and IFN-beta mRNA levels and mRNA levels of Mx, an antiviral effector molecule, were determined in lymphoid tissues of rhesus macaques infected with pathogenic SIV. IFN-alpha/beta responses were induced during the acute phase and persisted in various lymphoid tissues throughout the chronic phase of infection. IFN-alpha/beta responses were most consistent in tissues with high viral RNA levels; thus, IFN-alpha/beta responses were not generally associated with effective control of SIV replication. IFN-alpha/beta responses were differentially regulated in different lymphoid tissues and at different stages of infection. The most consistent IFN-alpha/beta responses in acute and chronic SIV infection were observed in peripheral lymph nodes. In the spleen, only a transient increase in IFN-alpha/beta mRNA levels during acute SIV infection was observed. Further, IFN-alpha and IFN-beta mRNA levels showed a tissue-specific expression pattern during the chronic, but not the acute, phase of infection. In the acute phase of infection, SIV RNA levels in lymphoid tissues of rhesus macaques correlated with mRNA levels of both IFN-alpha and IFN-beta, whereas during chronic SIV infection only increased IFN-alpha mRNA levels correlated with the level of virus replication in the same tissues. In lymphoid tissues of all SIV-infected monkeys, higher viral RNA levels were associated with increased Mx mRNA levels. We found no evidence that monkeys with increased Mx mRNA levels in lymphoid tissues had enhanced control of virus replication. In fact, Mx mRNA levels were associated with high viral RNA levels in lymphoid tissues of chronically infected animals.

Clinical tolerance and immunologic effects after single or repeated administrations of the synthetic immunomodulator murabutide in HIV-1-infected patients

Correction of the virus-induced deficits in innate immunity of HIV-infected subjects could well contribute to enhanced immune recovery and efficacious control of viral replication. The safe synthetic immunomodulator Murabutide (ISTAC Biotechnology, Lille, France) has been found to regulate the function of antigen-presenting cells and to selectively activate CD4 lymphocytes leading to dramatic suppression of HIV replication, in vitro. Therefore, as a first step toward the evaluation of the immunotherapeutic potential of Murabutide in HIV disease, we have conducted two phase 1/2 clinical trials to address the safety and the immunologic effects of Murabutide administration into HIV-infected subjects receiving antiretroviral therapy. The first study revealed that single administration of 5, 7, or 9 mg of Murabutide, to 6 patients per dose, was well tolerated. This was accompanied by a selective induction of cytokines and chemokines detectable in the serum, and the levels appeared to plateau at the 7-mg dose. The second study then evaluated the safety and biological effects of repeated administrations of 7 mg Murabutide, on 5 consecutive days, in 12 HIV-1-infected patients. A good clinical tolerance was noted throughout the study. Moreover, changes in several immune parameters, including downregulation of coreceptor expression on lymphocytes and improved lymphoproliferative responses, were detected during or/and up to 3 weeks after Murabutide administration. These encouraging results warrant further evaluation of longer periods or cycles of immunotherapy with Murabutide in HIV-infected subjects.

Cytokine therapy or structured treatment interruptions in HIV infection: which is best?

Continuous highly active antiretroviral therapy (HAART) is the treatment of choice for HIV patients in order to prevent opportunistic infection or AIDS-related morbidity and mortality. However, new HIV treatment strategies are needed to face the emerging problems related to long-term toxicities and failures of HAART. Moreover, total eradication and complete restoration of immune system function cannot be achieved by HAART alone. Therefore, in an attempt to increase the natural immunity of HIV-infected patients, immune-based therapies have been investigated. This review is intended to provide an update on the use of immune-based therapies, in particular structured treatment interruptions and cytokines, such as IL-2 and IFN-alpha, as potential stimulants of the immune system of patients with HIV-infections and to discuss risks and benefits of each alternative. Ongoing and future clinical trials will provide a rationale for their use in clinical practice and will determine how these strategies can be combined to optimise HAART.

Preferential and persistent depletion of CCR5+ T-helper lymphocytes with nonlymphoid homing potential despite early treatment of primary HIV infection

Strains of human immunodeficiency virus (HIV) transmitted between individuals use the CCR5 coreceptor, but no preferential depletion of particular Th-lymphocyte subpopulations has been reported during primary HIV infection (PHI). In contrast, gut-associated Th lymphocytes are preferentially depleted in macaques recently infected by simian immunodeficiency virus. The expression of CCR5 and the intestinal homing receptor integrin alpha4beta7 on subpopulations of Th lymphocytes was studied in 12 patients with PHI. There was a profound decrease of circulating alpha4beta7+ Th lymphocytes and CCR5+ memory Th lymphocytes with nonlymphoid homing potential (CD62L-CD45RO+). Unlike other Th lymphocytes, this cell population remained depleted despite early control of viral replication under antiretroviral treatment. Therefore, HIV preferentially targets a specific CCR5+ subpopulation of Th lymphocytes early during infection, inducing its persistent depletion despite treatment. Protective immunity in vivo depends on Th lymphocytes carrying homing capacity to nonlymphoid tissue, and therefore these data may explain the persistent abnormalities of immune functions in patients infected with HIV.