Impact of immune interventions on proviral HIV-1 DNA decay in patients receiving highly active antiretroviral therapy

GluT4: A central player in hippocampal memory and brain insulin resistance

Insulin is now well-established as playing multiple roles within the brain, and specifically as regulating hippocampal cognitive processes and metabolism. Impairments to insulin signaling, such as those seen in type 2 diabetes and Alzheimer's disease, are associated with brain hypometabolism and cognitive impairment, but the mechanisms of insulin's central effects are not determined. Several lines of research converge to suggest that the insulin-responsive glucose transporter GluT4 plays a central role in hippocampal memory processes, and that reduced activation of this transporter may underpin the cognitive impairments seen as a consequence of insulin resistance.

Two-Year Follow-Up of Macaques Developing Intermittent Control of the Human Immunodeficiency Virus Homolog Simian Immunodeficiency Virus SIVmac251 in the Chronic Phase of Infection

Off-therapy control of viremia by HIV-infected individuals has been associated with two likely players: a restricted viral reservoir and an efficient cell-mediated immune response. We previously showed that a combination of highly suppressive antiretroviral therapy and two experimental drugs, i.e., auranofin and buthionine sulfoximine, was able to reduce the viral reservoir, elicit efficient cell-mediated antiviral responses, and induce intermittent posttherapy viral load control in chronically SIVmac251-infected macaques. We here show that the macaques that had received this drug combination and then stopped antiretroviral therapy were also able to maintain low numbers of activated CD4+ T cells at viral rebound. Moreover, these macaques consistently displayed low-level simian immunodeficiency virus (SIV) diversity, which was in line with the strong and broadly reactive cell-mediated immune responses against conserved Gag antigens. Extended follow-up showed that the two macaques that had received the complete drug combination remained healthy and did not develop AIDS in 2 years of follow-up after therapy suspension. This disease-free survival is longer than twice the average time of progression to AIDS in SIVmac251-infected rhesus macaques. These results suggest that limited numbers of activated T cells at viral rebound and subsequent development of broadly reactive cell-mediated responses may be interrelated in reducing the viral reservoir.

IMPORTANCE

The HIV reservoir in CD4+ T cells represents one main obstacle to HIV eradication. Recent studies, however, show that a drastic reduction of this reservoir is insufficient for inducing a functional cure of AIDS. In the present work, we thoroughly studied and subjected to long-term follow-up two macaques showing intermittent control of the virus following suspension of antiretroviral therapy plus an experimental antireservoir treatment, i.e., the gold salt auranofin and the investigational chemotherapeutic agent buthionione sulfoximine (BSO). We found that these drugs were able to decrease the number of activated CD4+ T cells, which are preferential targets for HIV infection. Then, efficient immune responses against the virus were developed in the macaques, which remained healthy during 2 years of follow-up. This result may furnish another building block for future attempts to cure HIV/AIDS.

Long-term effects of intermittent IL-2 in HIV infection: extended follow-up of the INSIGHT STALWART Study

Background

The Study of Aldesleukin with and without Antiretroviral Therapy (STALWART) was designed to evaluate whether intermittent IL-2 alone or with peri-cycle ART increased CD4+ cell counts (and so delayed initiation of ART) in HIV infected individuals having ≥300 CD4+ cells/mm³ compared to untreated controls. When the results of two large clinical trials, ESPRIT and SILCAAT, showed no clinical benefit from IL-2 therapy, IL-2 administration was halted in STALWART. Because IL-2 recipients in STALWART experienced a greater number of opportunistic disease (OD) or death and adverse events (AEs), participants were asked to consent to an extended follow-up phase in order to assess persistence of IL-2 effects.

Methodology

Participants in this study were followed for clinical events and AEs every 4 months for 24 months. Unadjusted Cox proportional hazards models were used to summarize death, death or first OD event, and first grade 3 or 4 AE.

Principal Findings

A total of 267 persons were enrolled in STALWART (176 randomized to the IL-2 arms and 91 to the no therapy arm); 142 individuals in the IL-2 group and 80 controls agreed to enter the extended follow-up study. Initiation of continuous ART was delayed in the IL-2 groups, but once started, resulted in similar CD4+ cell and viral load responses compared to controls. The hazard ratios (95% CI) for IL-2 versus control during the extension phase for death or OD, grade 3 or 4 AE, and grade 4 AE were 1.45 (0.38, 5.45), 0.43 (0.24, 1.63) and 0.20 (0.04, 1.03), respectively. The hazard ratios for the AE outcomes were significantly lower during the extension than during the main study.

Conclusions

Adverse events associated with IL-2 cycling did not persist upon discontinuation of IL-2. The use of IL-2 did not impact the subsequent response to initiation of cART.

HIV DNA in circulating monocytes as a mechanism to dementia and other HIV complications

It is broadly accepted that HIV DNA in lymphoid and myeloid cells persists despite combination antiretroviral therapy. Recognized as the Achilles heel to HIV eradication, the role of these peripheral reservoirs in HIV morbidity is less well developed. The burden of HIV DNA in peripheral mononuclear cells is linked to HIV disease outcomes such as time to AIDS diagnosis, survival, and CD4 T-lymphocyte counts. Monocytes are a minor HIV DNA reservoir, and the burden of HIV DNA in these cells appears to be linked to dementia, suggesting that residual infection in this subset is linked to tissue-related HIV complications. Since monocytes are likely involved in trafficking virus to the brain, there is a strong mechanistic link underlying this discovery. Herein, we summarize our current understanding of monocyte HIV DNA and central nervous system dysfunction in humans. We present a model to understand these relationships and suggest possible treatment approaches to be tested.

HIV-1 DNA load analysis in peripheral blood lymphocytes and monocytes from naïve and HAART-treated individuals

OBJECTIVE

To evaluate HIV-1 DNA load in PBLs and monocytes from both long-term HAART-treated and antiretroviral naïve HIV-1 infected patients.

METHODS

Cross-sectional quantitative analysis of HIV-1 DNA load was performed in PBLs and monocytes, purified from 34 long-term HAART-treated and 34 naïve HIV-1 infected patients, and compared to RNA viral load and CD4+ cell count.

RESULTS

HAART-treated patients showed significantly lower levels of viral DNA both in PBLs and monocytes in comparison with naïve individuals. Variable levels of HIV-1 DNA amount in monocytes were detected in all naïve patients but only in 12 of 34 HAART-treated individuals. PBLs HIV-1 DNA load was inversely correlated to CD4+ cell count in naïve and HAART-treated patients whereas no association was detected in monocytes.

CONCLUSIONS

Long-term HAART decreased HIV-1 DNA load in PBLs and monocytes demonstrating a valuable inhibitor effect, especially in short-lived reservoirs. In addition, the positive correlation of DNA burden between PBLs and monocytes may suggest a dynamic relation between these reservoirs in the course of disease. HIV-1 DNA load quantitative analysis in PBLs and monocytes may be considered an important approach to study the HIV-1 reservoir and the effectiveness of HAART therapy in HIV-1 seropositive patients.

Stavudine, lamivudine and nevirapine combination therapy for treatment of HIV infection and AIDS in adults

BACKGROUND

A favourable regimen for people infected with HIV/AIDS is one that provides optimal efficacy, durability of antiretroviral activity, tolerability, and has low adverse effects and drug-drug interactions. The combination of the non-nucleoside reverse transcriptase inhibitor nevirapine (NVP), and two nucleoside reverse transcriptase inhibitors, stavudine (d4T) and lamivudine (3TC), is widely used as first-line therapy, especially in low-resource countries. Analysis of the efficacy, durability and tolerability of the regimen is thus important to clinicians, consumers and policy-makers living in both rich and poor countries.

OBJECTIVES

To examine the efficacy of the stavudine, lamivudine and nevirapine regimen for the treatment of HIV infection and AIDS in adults.

SEARCH STRATEGY

We used the comprehensive search strategy developed specifically by the Cochrane HIV/AIDS Review Group to identify HIV/AIDS randomised controlled trials, and searched the following electronic databases: MEDLINE (searched July 2004); Embase (searched October 2004); and CENTRAL (July 2004). This search was supplemented with a search of AIDSearch (April 2005) to identify relevant conference abstracts, as well as searching reference lists of all eligible articles. The search was not limited by language or publication status.

SELECTION CRITERIA

Randomised controlled trials of the stavudine, lamivudine and nevirapine regimen, compared with any other regimens for treating HIV/AIDS, in antiretroviral treatment-naive or antiretroviral treatment-experienced adults.

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed the methodological quality of the trials and extracted data.

MAIN RESULTS

Our search resulted in 1,148 records, of which two studies described trials that met our inclusion criteria. One trial was a small single-centre Australian trial of 70 antiretroviral-naive participants, while the other trial was a large, multicentre trial, conducted in 14 countries, of 1,216 antiretroviral-naive participants. In both trials over 60% of participants were male. As the therapeutic combinations compared in both trials were not identical, it was not possible to conduct a meta-analysis to increase the power of the results. The main findings, therefore, are from the much larger trial, which was of a high quality. This trial found that there was no statistically significant difference in the efficacy (measured by treatment failure) between nevirapine and efavirenz (EFZ), when used in combination with 3TC and d4T (RR = 1.16; 95%CI: 0.95, 1.41). There was no statistically significant difference between once daily or twice-daily dosing of NVP, when used in combination with 3TC and d4T (RR = 1.00; 95%CI: 0.83; 1.21). It also showed that, compared with NVP plus EFZ, 3TC and d4T, a once-daily dosing of NVP, in combination with 3TC and d4T, performs better in averting treatment failure (RR = 0.82; 95%CI: 0.67, 1.00) than does twice-daily dosing of NVP with 3TC and d4T (RR = 0.82; 95%CI: 0.69; 0.97). Frequency of toxicity was higher in participants receiving NVP, compared with EFZ.

AUTHORS' CONCLUSIONS

The combination of nevirapine, 3TC and d4T is as efficacious as a combination of efavirenz, 3TC and d4T. Once-daily NVP with twice-daily 3TC and d4T is as efficacious as twice-daily NVP, 3TC and d4T. However, toxicity may be increased in the once-daily NVP regime. Additional trials of sufficient duration are required to provide better evidence for the use of this combination as a first line therapy. Ideally, trials should use standardised assessment measures especially with respect to measuring viral load, so that results can be compared and combined in meta-analyses.

[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.

Outcome of ICSI in HIV-1-infected women

BACKGROUND

Since 2001, French law has permitted the use of assisted reproductive technology in human immunodeficiency virus (HIV)-1 infected women under strict conditions. This report describes a preliminary series of seropositive women who underwent assisted reproduction treatment at our facility. To minimize contamination of culture media, equipment, and therefore of male gametes and embryos, we chose to perform ICSI in all cases. The outcome of ICSI was compared with the outcome in an age-matched group of non-HIV-1-infected women. Since several previous reports have indicated that HIV infection may be associated with a decrease in spontaneous fertility, our goal was also to assess the fertility status of the HIV-1-infected women entering our ICSI programme.

METHODS

The French law governing the use of assisted reproduction protocols in HIV-1-infected women was strictly applied. The inclusion criteria were absence of ongoing disease, CD4((+)) count >200 cells/mm(3), and stable HIV-1 RNA level. Since mean age at the time of ICSI was higher in HIV-1-infected women than in the overall group of non-HIV-infected women, we compared outcome data in HIV-1-infected women (group I) to a group of non-HIV-1-infected women matched with regard to age and follicle retrieval period (group II) as well as to the overall group of women who underwent ICSI at our institution (group III).

RESULTS

A total of 66 ovarian stimulations was performed in 29 HIV-1-infected-infected women. The percentage of cancelled cycles was higher in infected women than in matched controls (15.2 versus 4.9%, P < 0.05). The duration of ovarian stimulation (13.3 versus 11.7 days, P < 0.05) and amount of recombinant FSH injected (2898 versus 2429 IU, P < 0.001) were also higher in infected women. The number of retrieved oocytes, mature oocytes, and embryos obtained as well as embryo quality was similar in all groups. The fertilization rate was higher in infected women than in matched controls (67 versus 60%, P < 0.01). The pregnancy rate was not significantly different between groups I and II (16.1 versus 19.6%) in spite of the fact that the number of embryos transferred was purposefully restricted in the HIV-1-infected group to minimize multiple pregnancy (2.0 versus 2.4, not significant).

CONCLUSION

The results of this preliminary series of ICSI cycles in HIV-1-infected women indicate that optimal ovarian stimulation is slightly more difficult to achieve than in matched seronegative women. However, when criteria for oocyte retrieval were fulfilled, ICSI results were similar to those of age-matched controls.

Quantitative DNA proviral detection in HIV-1 patients treated with antiretroviral therapy

The amount of proviral DNA in peripheral blood mononuclear cells (PBMCs) from 93 HIV-1 seropositive patients on long-lasting antiretroviral therapy was measured by the SYBR green real-time PCR technique. Variable levels of proviral DNA, ranging from 14 to 1847 copies of HIV-1 DNA per 10(6) PBMC were found, without a significant correlation between proviral load and plasma HIV-1 RNA levels or CD4(+) lymphocyte counts. To investigate the possible role of HIV-1 DNA levels as prognostic markers in clinical practice, the amount of proviral DNA and peripheral blood CD4(+) lymphocyte counts were further evaluated after 5 months of continued therapy in 32 patients who maintained a persistently undetectable viremia throughout the observation period. Interestingly, a clear-cut decrease (> or =0.5 log) in proviral DNA levels was significantly associated with a definite increase in CD4(+) lymphocyte counts. Even though plasma HIV-1 RNA levels remain the basic parameter to monitor both the intensity of viral replication and the efficacy of therapeutic interventions, the results obtained in our study seem to indicate that measuring proviral DNA levels could represent an adjunct prognostic marker, especially useful in patients whose HIV-1 RNA levels drop below detectable limits.

Acute HIV revisited: new opportunities for treatment and prevention

Inability to recognize incident infection has traditionally limited both scientific and public health approaches to HIV disease. Recently, some laboratories have begun adding HIV nucleic acid amplification testing to HIV diagnostic testing algorithms so that acute (antibody-negative) HIV infections can be routinely detected within the first 1-3 weeks of exposure. In this review article, we will highlight critical opportunities for HIV treatment and prevention that are presented by these diagnostic strategies.

Tenofovir disoproxil fumarate

OBJECTIVE

To review the pharmacology, virology, pharmacokinetics, efficacy, safety, resistance profile, and clinical use of tenofovir disoproxil fumarate.

DATA SOURCES

A MEDLINE search was performed (1966-August 2002) using the following terms: tenofovir, tenofovir disoproxil fumarate, PMPA (9-(R)-[2-(phosphonomethoxy)propyl]adenine), and Viread. Abstracts from HIV-related meetings were reviewed. DATA EXTRACTION AND STUDY SELECTION: Publications and meeting abstracts regarding tenofovir were reviewed. The most recent and pertinent items were included.

DATA SYNTHESIS

Tenofovir disoproxil fumarate is a nucleotide prodrug that is diphosphorylated to its active moiety, tenofovir diphosphate. In this form, tenofovir acts as a reverse transcriptase inhibitor to inhibit HIV-1 replication. In clinical trials, tenofovir was effective at suppressing HIV-1 RNA and boosting CD4+ cell counts. Tenofovir has a long intracellular half-life, which permits once-daily dosing. Since tenofovir does not interact with the cytochrome P450 pathway, it exhibits minimal drug interactions, with the exception of didanosine. Compared with other reverse transcriptase inhibitors, tenofovir may have advantages in terms of toxicity and medication adherence profiles. Ongoing studies are also analyzing tenofovir's activity against hepatitis B virus.

CONCLUSIONS

Tenofovir has been shown to be active against HIV-1 in combination with other antiretrovirals. The drug's benefit as a single-agent intensifier of highly active antiretroviral therapy in treatment-experienced patients has been established, and preliminary data for treatment-naïve patients are encouraging.

Increase of HIV-1 Pro-Viral Dna per Million Peripheral Blood Mononuclear Cells in Patients with Advanced HIV Disease (Cd4<200 Cells/Mm3) Receiving Interleukin 2 Combined with Haart Versus Haart Alone (Anrs-082 Trial)

Objective

To assess the effect of interleukin (IL)-2 combined with highly active antiretroviral therapy (HAART) on HIV-1 pro-viral DNA quantification in HIV-1-infected patients with CD4<200/mm3.

Patients and methods

Seventy patients with CD4<200 cells/mm3 and CV<1000 copies/ml were enrolled in a 6-month randomized controlled study to evaluate the subcutaneous injection of IL-2 in addition to HAART versus HAART alone. Then, in a non-comparative phase from week 28 to week 80, IL-2 was proposed to patients from both groups. The HIV-1 pro-viral DNA was quantified at baseline, week 24 and week 50 by a real-time polymerase chain reaction (PCR) assay in peripheral blood mononuclear cells (PBMC). Analysis of resistance mutations was performed at baseline and after 6-months of IL-2.

Results

HIV-1 DNA level in PBMC increased significantly in patients treated with 6 months of HAART combined to IL-2 (+0.24 log10, P=0.009) compared to a slight decrease in patients treated with HAART alone (–0.05 log10). Moreover, a DNA increase was observed in control group patients when receiving 6 months of IL-2 (+0.34 log10). No increase of HIV-1 DNA was seen when this measure was expressed per million CD4 cells; it was probably hidden by the intense increase of CD4 lymphocytes after 6 months of IL-2 administration. No evolution of resistance mutations in pro-viral DNA was observed during 6 months of IL-2, despite the increase of pro-viral DNA and the occurrence of transient increase of viraemia.

Conclusion

Administration of IL-2 combined with HAART in HIV-1 infected-patients with advanced disease led to an increase of HIV-1 pro-viral DNA per million PBMC without virological failure or emergence of resistance.

Cell-associated HIV DNA measured early during infection has prognostic value independent of serum HIV RNA measured concomitantly

Using data from the Danish AIDS Cohort of HIV-infected homosexual men established in the 1980s, the prognostic value of early HIV DNA loads was evaluated. In addition to DNA measurements, concomitant serum HIV RNA levels, CD4 cell counts and CCR5 genotypes were determined. The patients were divided into 3 groups, according to whether their cell-associated HIV DNA load was < or = 100, 500 or > or = 2,500 DNA copies/10(6) peripheral blood mononuclear cells. Clinical progression rates differed significantly between the groups (p < 0.005). Cell-associated HIV DNA load had prognostic value independent of serum HIV RNA (p < 0.02). However, when HIV DNA, HIV RNA and CD4 cell counts were all included in a Cox model, only serum HIV RNA had independent prognostic value. Patients heterozygous for the CCR5 delta 32 allele had significantly lower HIV DNA loads than those homozygous for the normal allele (p < 0.05). The interplay between HIV RNA and DNA levels is discussed, together with the possibility that cell-associated HIV DNA load is a marker of the HIV RNA peak seen shortly after primary HIV infection.

Evaluation of PCR-based methods for the quantitation of integrated HIV-1 DNA

Integration of HIV-1 DNA is essential both for productive viral replication and for viral persistence in patients. Methods to measure specifically proviral HIV DNA are required for investigating the mechanisms of HIV integration, for screening novel integrase inhibitors in cell culture and for monitoring levels of persistent integrated viral DNA in patients. In this report, the linker primer polymerase chain reaction (LP-PCR) and Alu-PCR methods for the quantitation of integrated HIV-1 DNA have been modified and evaluated. Each of the two modified assays allowed the quantitative detection of 4 copies of integrated HIV DNA in presence of 2 x 10(5) cell-equivalents of human chromosomal DNA. The results show that proper DNA isolation procedures and the inclusion of appropriate controls in these assays are important for the accurate quantitation of integrated HIV DNA. With further improvements, it should be possible to use these methods as diagnostic tools to monitor closely the efficacy of antiretroviral therapy.