Immunological benefits of antiretroviral therapy in very early stages of asymptomatic chronic HIV-1 infection

Glutaminolysis of CD4+ T Cells: A Potential Therapeutic Target in Viral Diseases

CD4+ T cells play a critical role in the pathogenesis of viral diseases, which are activated by the internal metabolic pathways encountering with viral antigens. Glutaminolysis converts glutamine into tricarboxylic acid (TCA) circulating metabolites by α-ketoglutaric acid, which is essential for the proliferation and differentiation of CD4+ T cells and plays a central role in providing the energy and structural components needed for viral replication after the virus hijacks the host cell. Changes in glutaminolysis in CD4+ T cells are accompanied by changes in the viral status of the host cell due to competition for glutamine between immune cells and host cells. More recently, attempts have been made to treat tumours, autoimmune diseases, and viral diseases by altering the breakdown of glutamine in T cells. In this review, we will discuss the current knowledge of glutaminolysis in the CD4+ T cell subsets from viral diseases, not only increasing our understanding of immunometabolism but also providing a new perspective for therapeutic target in viral diseases.

People With Human Immunodeficiency Virus Receiving Suppressive Antiretroviral Therapy Show Typical Antibody Durability After Dual Coronavirus Disease 2019 Vaccination and Strong Third Dose Responses

BACKGROUND

Longer-term humoral responses to 2-dose coronavirus disease 2019 (COVID-19) vaccines remain incompletely characterized in people living with human immunodeficiency virus (HIV) (PLWH), as do initial responses to a third dose.

METHODS

We measured antibodies against the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike protein receptor-binding domain, angiotensin-converting enzyme 2 (ACE2) displacement, and viral neutralization against wild-type and Omicron strains up to 6 months after 2-dose vaccination, and 1 month after the third dose, in 99 PLWH receiving suppressive antiretroviral therapy and 152 controls.

RESULTS

Although humoral responses naturally decline after 2-dose vaccination, we found no evidence of lower antibody concentrations or faster rates of antibody decline in PLWH compared with controls after accounting for sociodemographic, health, and vaccine-related factors. We also found no evidence of poorer viral neutralization in PLWH after 2 doses, nor evidence that a low nadir CD4+ T-cell count compromised responses. Post-third-dose humoral responses substantially exceeded post-second-dose levels, though Omicron-specific responses were consistently weaker than responses against wild-type virus. Nevertheless, post-third-dose responses in PLWH were comparable to or higher than controls. An mRNA-1273 third dose was the strongest consistent correlate of higher post-third-dose responses.

CONCLUSION

PLWH receiving suppressive antiretroviral therapy mount strong antibody responses after 2- and 3-dose COVID-19 vaccination. Results underscore the immune benefits of third doses in light of Omicron.

Immune Checkpoint Molecules and Glucose Metabolism in HIV-Induced T Cell Exhaustion

The progressive decline of CD8+ cytotoxic T cells in human immunodeficiency virus (HIV)-infected patients due to infection-triggered cell exhaustion and cell death is significantly correlated with disease severity and progression into the life-threatening acquired immunodeficiency syndrome (AIDS) stage. T cell exhaustion is a condition of cell dysfunction despite antigen engagement, characterized by augmented surface expression of immune checkpoint molecules such as programmed cell death protein 1 (PD-1), which suppress T cell receptor (TCR) signaling and negatively impact the proliferative and effector activities of T cells. T cell function is tightly modulated by cellular glucose metabolism, which produces adequate energy to support a robust reaction when battling pathogen infection. The transition of the T cells from an active to an exhausted state following pathogen persistence involves a drastic change in metabolic activity. This review highlights the interplay between immune checkpoint molecules and glucose metabolism that contributes to T cell exhaustion in the context of chronic HIV infection, which could deliver an insight into the rational design of a novel therapeutic strategy.

Immunogenicity to COVID-19 mRNA vaccine third dose in people living with HIV

In order to investigate safety and immunogenicity of SARS-CoV-2 vaccine third dose in people living with HIV (PLWH), we analyze anti-RBD, microneutralization assay and IFN-γ production in 216 PLWH on ART with advanced disease (CD4 count <200 cell/mm3 and/or previous AIDS) receiving the third dose of a mRNA vaccine (BNT162b2 or mRNA-1273) after a median of 142 days from the second dose. Median age is 54 years, median CD4 nadir 45 cell/mm3 (20-122), 93% HIV-RNA < 50 c/mL. In 68% of PLWH at least one side-effect, generally mild, is recorded. Humoral response after the third dose was strong and higher than that achieved with the second dose (>2 log2 difference), especially when a heterologous combination with mRNA-1273 as third shot is used. In contrast, cell-mediated immunity remain stable. Our data support usefulness of third dose in PLWH currently receiving suppressive ART who presented with severe immune dysregulation.

Antiretroviral therapy duration and immunometabolic state determine efficacy of ex vivo dendritic cell-based treatment restoring functional HIV-specific CD8+ T cells in people living with HIV

Background

Dysfunction of CD8⁺ T cells in people living with HIV-1 (PLWH) receiving anti-retroviral therapy (ART) has restricted the efficacy of dendritic cell (DC)-based immunotherapies against HIV-1. Heterogeneous immune exhaustion and metabolic states of CD8⁺ T cells might differentially associate with dysfunction. However, specific parameters associated to functional restoration of CD8⁺ T cells after DC treatment have not been investigated.

Methods

We studied association of restoration of functional HIV-1-specific CD8⁺ T cell responses after stimulation with Gag-adjuvant-primed DC with ART duration, exhaustion, metabolic and memory cell subsets profiles.

Findings

HIV-1-specific CD8⁺ T cell responses from a larger proportion of PLWH on long-term ART (more than 10 years; LT-ARTp) improved polyfunctionality and capacity to eliminate autologous p24⁺ infected CD4⁺ T cells in vitro. In contrast, functional improvement of CD8⁺ T cells from PLWH on short-term ART (less than a decade; ST-ARTp) after DC treatment was limited. This was associated with lower frequencies of central memory CD8⁺ T cells, increased co-expression of PD1 and TIGIT and reduced mitochondrial respiration and glycolysis induction upon TCR activation. In contrast, CD8⁺ T cells from LT-ARTp showed increased frequencies of TIM3⁺ PD1⁻ cells and preserved induction of glycolysis. Treatment of dysfunctional CD8⁺ T cells from ST-ARTp with combined anti-PD1 and anti-TIGIT antibodies plus a glycolysis promoting drug restored their ability to eliminate infected CD4⁺ T cells.

Interpretation

Together, our study identifies specific immunometabolic parameters for different PLWH subgroups potentially useful for future personalized DC-based HIV-1 vaccines.

Funding

NIH (R21AI140930), MINECO/FEDER RETOS (RTI2018-097485-A-I00) and CIBERINF grants.

People with HIV receiving suppressive antiretroviral therapy show typical antibody durability after dual COVID-19 vaccination, and strong third dose responses

Background:

Longer-term humoral responses to two-dose COVID-19 vaccines remain incompletely characterized in people living with HIV (PLWH), as do initial responses to a third dose.

Methods:

We measured antibodies against the SARS-CoV-2 spike protein receptor-binding domain, ACE2 displacement and viral neutralization against wild-type and Omicron strains up to six months following two-dose vaccination, and one month following the third dose, in 99 PLWH receiving suppressive antiretroviral therapy, and 152 controls.

Results:

Though humoral responses naturally decline following two-dose vaccination, we found no evidence of lower antibody concentrations nor faster rates of antibody decline in PLWH compared to controls after accounting for sociodemographic, health and vaccine-related factors. We also found no evidence of poorer viral neutralization in PLWH after two doses, nor evidence that a low nadir CD4+ T-cell count compromised responses. Post-third-dose humoral responses substantially exceeded post-second-dose levels, though anti-Omicron responses were consistently weaker than against wild-type. Nevertheless, post-third-dose responses in PLWH were comparable to or higher than controls. An mRNA-1273 third dose was the strongest consistent correlate of higher post-third-dose responses.

Conclusion:

PLWH receiving suppressive antiretroviral therapy mount strong antibody responses after two- and three-dose COVID-19 vaccination. Results underscore the immune benefits of third doses in light of Omicron.

Humoral immune responses to COVID-19 vaccination in people living with HIV receiving suppressive antiretroviral therapy

Humoral responses to COVID-19 vaccines in people living with HIV (PLWH) remain incompletely characterized. We measured circulating antibodies against the SARS-CoV-2 spike protein receptor-binding domain (RBD), ACE2 displacement and viral neutralization activities one month following the first and second COVID-19 vaccine doses, and again 3 months following the second dose, in 100 adult PLWH and 152 controls. All PLWH were receiving suppressive antiretroviral therapy, with median CD4+ T-cell counts of 710 (IQR 525-935) cells/mm3, though nadir CD4+ T-cell counts ranged as low as <10 cells/mm3. After adjustment for sociodemographic, health and vaccine-related variables, HIV infection was associated with lower anti-RBD antibody concentrations and ACE2 displacement activity after one vaccine dose. Following two doses however, HIV was not significantly associated with the magnitude of any humoral response after multivariable adjustment. Rather, older age, a higher burden of chronic health conditions, and dual ChAdOx1 vaccination were associated with lower responses after two vaccine doses. No significant correlation was observed between recent or nadir CD4+ T-cell counts and responses to two vaccine doses in PLWH. These results indicate that PLWH with well-controlled viral loads and CD4+ T-cell counts in a healthy range generally mount strong initial humoral responses to dual COVID-19 vaccination. Factors including age, co-morbidities, vaccine brand, response durability and the rise of new SARS-CoV-2 variants will influence when PLWH will benefit from additional doses. Further studies of PLWH who are not receiving antiretroviral treatment or who have low CD4+ T-cell counts are needed, as are longer-term assessments of response durability.

Humoral immune responses to COVID-19 vaccination in people living with HIV receiving suppressive antiretroviral therapy

Humoral responses to COVID-19 vaccines in people living with HIV (PLWH) remain incompletely understood. We measured circulating antibodies against the receptor-binding domain (RBD) of the SARS-CoV-2 spike protein, ACE2 displacement and live viral neutralization activities one month following the first and second COVID-19 vaccine doses in 100 adult PLWH and 152 controls. All PLWH were receiving suppressive antiretroviral therapy, with median CD4+ T-cell counts of 710 (IQR 525-935) cells/mm 3 . Nadir CD4+ T-cell counts ranged as low as <10 (median 280; IQR 120-490) cells/mm 3 . After adjustment for sociodemographic, health and vaccine-related variables, HIV infection was significantly associated with 0.2 log 10 lower anti-RBD antibody concentrations (p=0.03) and ∼11% lower ACE2 displacement activity (p=0.02), but not lower viral neutralization (p=0.1) after one vaccine dose. Following two doses however, HIV was no longer significantly associated with the magnitude of any response measured. Rather, older age, a higher burden of chronic health conditions, and having received two ChAdOx1 doses (versus a heterologous or dual mRNA vaccine regimen) were independently associated with lower responses. After two vaccine doses, no significant correlation was observed between the most recent or nadir CD4+ T-cell counts and vaccine responses in PLWH. These results suggest that PLWH with well-controlled viral loads on antiretroviral therapy and CD4+ T-cell counts in a healthy range will generally not require a third COVID-19 vaccine dose as part of their initial immunization series, though other factors such as older age, co-morbidities, vaccine regimen type, and durability of vaccine responses will influence when this group may benefit from additional doses. Further studies of PLWH who are not receiving antiretroviral treatment and/or who have low CD4+ T-cell counts are needed.

Immune recovery in HIV-1 infected patients with sustained viral suppression under long-term antiretroviral therapy in Ethiopia

BACKGROUND

There is very little data on long-term immune recovery responses in patients on suppressive antiretroviral therapy (ART) in the setting of sub-Saharan Africa (SSA). Thus, we sought to determine CD4+ T-cell, CD8+ T-cell and CD4/CD8 ratio responses in a cohort of HIV infected individuals on sustained suppressive ART followed up for more than a decade.

METHODS

The cohort comprised adult patients who started ART between 2001 and 2007 and followed for up to 14 years. Trends in median CD4+ T-cells, CD8+ T-cells and CD4/CD8 ratio were reviewed retrospectively. Poisson regression models were used to identify factors associated with achieving normalized T-cell biomarkers. Kaplan-Meier curves were used to estimate the probability of attaining normalized counts while on suppressive ART.

RESULTS

A total of 227 patients with a median duration of follow-up on ART of 12 (IQR: 10.5-13.0) years were included. CD4 cell count increased from baseline median of 138 cells (IQR: 70-202) to 555 cells (IQR: 417-830). CD4 cell increased continuously up until 5 years, after which it plateaued up until 14 years of follow up. Only 69.6% normalized their CD4 cell count within a median of 6.5 (IQR: 3.0-10.5) years. In addition, only 15.9% of the cohort were able to achieve the median reference CD4+ T-cell threshold count in Ethiopians (≈760 cells/μL). CD8+ T-cell counts increased initially until year 1, after which continuous decrease was ascertained. CD4/CD8 ratio trend revealed continuous increase throughout the course of ART, and increased from a median baseline of 0.14 (IQR: 0.09-0.22) to a median of 0.70 (IQR: 0.42-0.95). However, only 12.3% normalized their ratio (≥ 1.0) after a median of 11.5 years. In addition, only 8.8% of the cohort were able to achieve the median reference ratio of healthy Ethiopians.

CONCLUSION

Determination of both CD4+ and CD8+ T-cells, along with CD4/CD8 ratio is highly relevant in long-term follow-up of patients to assess immune recovery. Monitoring ratio levels may serve as a better biomarker risk for disease progression among patients on long-term ART. In addition, the findings emphasize the relevance of initiation of ART at the early stage of HIV-1 infection.

Extremely low viral reservoir in treated chronically HIV-1-infected individuals

BACKGROUND

Small viral reservoirs are found predominantly in HIV-1 controllers and individuals treated during acute/early HIV-1 infection. However, other HIV⁺ individuals could naturally also harbour low viral reservoirs.

METHODS

We screened 451 HIV-1-infected treated-individuals with suppressed plasma viremia for at least 3 years and stored cryopreserved peripheral blood mononuclear cells (PBMCs). Total HIV-DNA was analysed in PBMCs with ddPCR. Individuals with <50 HIV-DNA copies/10⁶ PBMCs constitute the 'Low Viral Reservoir Treated' cohort (LoViReT). Longitudinal samples were obtained from 12 chronically treated LoViReT and compared to 13 controls (>50 HIV-DNA copies/10⁶ PBMCs) to analyse total HIV-DNA, T-cell and NK-cell populations, HIV-1 specific antibodies, and plasma inflammation markers.

FINDINGS

We found that 9.3% of the individuals screened had <50 HIV-DNA copies/10⁶ PBMCs. At least 66% initiated cART during the chronic phase of HIV-1 infection (cp-LoViReT). Cp-LoViReT harboured lower levels of HIV-DNA before cART and after treatment introduction the decays were greater compared to controls. They displayed a marked decline in quantity and avidity in HIV-specific antibodies after initiation of cART. Cp-LoViReT had fewer CD8⁺ T_TM and T_EMRA in the absence of cART, and higher CD8⁺ T_N after 18 months on therapy.

INTERPRETATION

Treated chronically HIV-1-infected LoViReT represent a new phenotype of individuals characterized by an intrinsically reduced viral reservoir, less impaired CD8⁺ T-cell compartment before cART, and low circulating HIV-1 antigens despite being treated in the chronic phase of infection. The identification of this unique group of individuals is of great interest for the design of future eradication studies.

FUNDING

MSD Spain.

Role of CD4/CD8 ratio on the incidence of tuberculosis in HIV-infected patients on antiretroviral therapy followed up for more than a decade

Background

The role of CD4/CD8 ratio on the incidence of tuberculosis (TB) in patients on antiretroviral therapy (ART) is unknown. Thus, we sought to determine whether the CD4/CD8 ratio was associated with development of TB in a cohort of HIV infected individuals on ART followed up for more than a decade in the setting of sub-Saharan Africa (SSA).

Methods

The cohort comprised adult patients who started ART between 2001 and 2007 and followed for up to 15 years. Clinical data were collected in retrospective manner. Patients with an AIDS defining illness or a CD4 count <200 cell/μL were started with a combination of ART. The participants have clinic visits every 6 months and/or as needed. Poisson regression models were used to identify factors associated with development of incident TB. Kaplan-Meier curves were used to estimate the probability of incident TB while on ART.

Results

A total of 347 patients with a median duration of follow-up on ART of 11.5 (IQR: 10.0–12.5) years were included. Incident TB developed in 47 patients during the 3259 person-years of follow-up, the majority (76.6%) occurred within five year of ART initiation. On univariate analysis, poor ART adherence (RR:2.57, 95% CI: 1.28–5.17), time-updated CD4 cell count of lower than 200 (RR: 4.86, 95%CI 2.33–10.15), or CD4 cell count between 200 and 500 (RR: 4.68, 95% CI: 2.17–10.09), time-updated CD8 cell count lower than 500 (RR: 2.83 95% CI 1.31–6.10), or CD8 cell count over 1000 (RR: 2.23, 95% CI: 1.12–4.45), time-updated CD4/CD8 ratio of less than 0.30 (RR: 6.00, 95% CI: 2.96–12.14), lack of normalization of CD4 T-cell count (RR: 6.13, 95% CI: 2.20–17.07), and virological failure (RR: 2.35 (95% CI: 1.17–4.71) were all associated with increased risk of incident TB. In multivariate analysis, however, time-updated CD4/CD8 ratio of less than 0.30 (adjusted RR: 4.08, 95% CI: 1.31–12.68) was the only factor associated with increased risk of developing incident TB (p = 0.015). Similar results were obtained in a sensitivity analysis by including only those virally suppressed patients (n = 233, 69% of all patients). In this group, CD4/CD8 ratio of less than 0.30 was associated with development of incident TB (adjusted RR: 4.02, 95% CI: 1.14–14.19, p = 0.031). Overall, the incidence rate of TB in patients with an updated CD4/CD8 ratio of less than 0.30 was more than 5-fold higher when compared with those with a ratio more than 0.45.

Conclusion

Low CD4/CD8 ratio is independently associated with an increased risk of incident TB despite viral suppression. CD4/CD8 ratio may serve as a biomarker for identifying patients at risk of TB in patients on ART in the setting of SSA.

The Dark Side of Female HIV Patient Care: Sexual and Reproductive Health Risks in Pre- and Post-Clinical Treatments

This study examines the pre- and post-clinical issues in human immunodeficiency virus (HIV) care and treatment for women and girls of high-risk population groups—namely sex workers, injecting drug users, women living with HIV, primary sexual partners of people living with HIV, adolescent girls who are children of these groups, and migrant young girls and women—in five provinces and cities in Vietnam. Through a sample of 241 surveyed participants and 48 respondents for in-depth interviews and 32 respondents in the focus group discussions, the study identifies multiple barriers that keep these groups from receiving the proper health care that is well within their human rights. Most respondents rated HIV testing as easily accessible, yet only 18.9% of the surveyed women living with HIV disclosed their infection status, while 37.8% gave no information at the most recent prenatal care visit. The level of knowledge and proper practices of sexual and reproductive health (SRH) care also remains limited. Meanwhile, modern birth control methods have yet to be widely adopted among these populations: only 30.7% of respondents reported using condoms when having sex with their husband. This increases the risks of unwanted pregnancy and abortion, as well as vulnerability to sexually transmitted infections (STIs) and HIV transmission. On the other hand, HIV-related stigma and discrimination at health care settings are still pervasive, which create significant barriers for patients to access proper care services. Based on these results, six recommendations to improve SRH status of women and girls of populations at high risk are put forward.

The effect of interrupted anti-retroviral treatment on the reconstitution of memory and naive T cells during tuberculosis treatment in HIV patients with active pulmonary tuberculosis

BACKGROUND

The reconstitution of cellular immune components contributes to clinical outcome of HIV and Mycobacterium tuberculosis (MTB) infection. Interruption of anti-retroviral therapy (ART) could lead to perturbations in reconstitution of T cells in HIV/ tuberculosis (TB) patients.

OBJECTIVES

To ascertain the effect of interrupted ART on reconstitution of CD4+ and CD8+ T sub-sets in TB patients.

METHODS

Participants with HIV (CD4>350 cells/µL) and TB were recruited under a larger phase 3 open label randomised controlled clinical trial. The CD45RO and CD62L markers were measured on CD4+ and CD8+ cells by flow cytometry. Samples were analysed at baseline, 3, 6, 12 months.

RESULTS

There was a significant increase of naive CD8+ cells (p = 0.003) and a decrease in effector CD8+ cells (p = 0.004) among participants in ART/TB treatment arm during the first 6 months. Withdrawing ART led to naive CD8+ cells reduction (p=0.02) to values close to baseline. An increase of naive CD8+ cells after 6 months of TB treatment in TB alone treatment arm (p=0.01) was observed. A trend towards increment of naive CD4+ sub sets in either treatment arms was observed.

CONCLUSION

Interrupting ART alters CD8+ but not CD4+ sub-sets in patients with less advanced HIV infection and TB.

HIV-DNA content in different CD4+ T-cell subsets correlates with CD4+ cell : CD8+ cell ratio or length of efficient treatment

OBJECTIVES

HIV establishes a latent infection at different degrees within naïve (TN) or central (TCM) and effector memory (TEM) CD4 T cell. Studying patients in whom HIV production was suppressed by combined antiretroviral therapy, our main aim was to find which factors are related or can influence intracellular viral reservoir in different CD4 T-cell subsets.

METHODS

We enrolled 32 HIV patients successfully treated for more than 2 years, with a CD4 T-cell count more than 500 cells/μl and plasma viremia undetectable from at least 1 year. Proviral HIV-DNA, the amount of cells expressing signal-joint T-cell receptor rearrangement excision circles and telomere length were quantified by droplet digital PCR in highly purified, sorted CD4 T-cell subsets; plasma IL-7 and IL-15 were measured by ELISA.

RESULTS

HIV-DNA was significantly lower in TN cells compared with TCM or to TEM. Conversely, TN cells contained more signal-joint T-cell receptor rearrangement excision circles compared with TCM or to TEM; no appreciable changes were observed in telomere length. HIV-DNA content was significantly higher in TN and TCM cells, but not in TEM, from patients with shorter time of treatment, or in those with lower CD4 : CD8 ratio.

CONCLUSION

Length of treatment or recovery of CD4 : CD8 ratio significantly influences viral reservoir in both TN and TCM. Measuring HIV-DNA in purified lymphocyte populations allows a better monitoring of HIV reservoir and could be useful for designing future eradication strategies.

Impact of Vaccination on Distribution of T Cell Subsets in Antiretroviral-Treated HIV-Infected Children

Antiretroviral therapy (ART) is generally prescribed to patients with human immunodeficiency virus (HIV) infection with vaccination introduced to prevent disease complications. However, little is known about the influence of immunization on T cell subsets' distribution during the course of infection. This study aims to identify the impact of viral replication and immunization on naïve, effector, effector memory, and central memory T cell subpopulations in ART-treated HIV-infected children. Fifty patients were recruited and injected intramuscularly with influenza A (H1N1) 2009 vaccine on the day of enrollment (day 0) and day 28. Blood samples were collected for pre- and postvaccination on days 0 and 56 for analyzing T cell phenotypes by flow cytometry. Phenotypes of all T cell subsets remained the same after vaccination, except for a reduction in effector CD8⁺ T cells. Moreover, T cell subsets from patients with controllable viral load showed similar patterns to those with virological failure. Absolute CD4 count was also found to have a positive relationship with naïve CD4⁺ and CD8⁺ T cells. In conclusion, vaccination and viral replication have a little effect on the distribution of T cell subpopulations. The CD4 count can be used for prediction of naïve T cell level in HIV-infected patients responding to ART.

New challenges in therapeutic vaccines against HIV infection

INTRODUCTION

There is a growing interest in developing curative strategies for HIV infection. Therapeutic vaccines are one of the most promising approaches. We will review the current knowledge and the new challenges in this research field. Areas covered: PubMed and ClinicalTrial.gov databases were searched to review the progress and prospects for clinical development of immunotherapies aimed to cure HIV infection. Dendritic cells (DC)-based vaccines have yielded the best results in the field. However, major immune-virologic barriers may hamper current vaccine strategies. We will focus on some new challenges as the antigen presentation by DCs, CTL escape mutations, B cell follicle sanctuary, host immune environment (inflammation, immune activation, tolerance), latent reservoir and the lack of surrogate markers of response. Finally, we will review the rationale for designing new therapeutic vaccine candidates to be used alone or in combination with other strategies to improve their effectiveness. Expert commentary: In the next future, the combination of DCs targeting candidates, inserts to redirect responses to unmutated parts of the virus, adjuvants to redirect responses to sanctuaries or improve the balance between activation/tolerance (IL-15, anti-PD1 antibodies) and latency reversing agents could be necessary to finally achieve the remission of HIV-1 infection.

Baseline CD4 T Cell Level Predicts Recovery Rate after Initiation of ART in HIV Infected Nigerians

The most characteristic immunologic disorder in HIV infection is the progressive loss of CD4 T lymphocytes, thus, it remains the most important and commonly used marker for monitoring of immune status of HIV-infected individuals. This study monitored CD4 T lymphocyte cell dynamics among HIV patients on ART, and consequently defined an optimal baseline level required for enhanced ARV treatment. Ninety-eight (M = 33; F = 65) out of 106 consenting HIV-infected ARV-naïve patients enrolled and monitored for 24 months were considered in the analysis. The patients were classified into four groups based on baseline CD4 T lymphocyte cell levels, and specific parameters were evaluated at interval. Median CD4 T lymphocyte increased from 114 (Range: 6-330) at baseline to highest 357 (Range: 15-1036) cells/μL at 18 months of therapy. Fifty (51.0%), 58(59.2%), 75(76.5%), 69(70.4%), 63(64.3%), and 69(70.4%) doubled their preceding CD4 levels during the 3(rd), 6(th), 9(th), 12(th), 18(th), and 24(th) months of ART, respectively. Maximum 337, 302, 360, and 475 cells/μL of blood were attained by groups commenced on ART with baseline CD4 ≤ 50, 51-100, 101-200, and 201-350 cells/μL of blood, respectively. The results show that higher baseline CD4 T lymphocyte cell level correlates with enhanced restoration and plateau after commencement of ART.

Comparative Impact of Suppressive Antiretroviral Regimens on the CD4/CD8 T-Cell Ratio: A Cohort Study

Although different factors have been implicated in the CD4/CD8 T-cell ratio recovery in HIV-infected patients who receive effective antiretroviral therapy (ART), limited information exists on the influence of the regimen composition. A longitudinal study carried out in a prospective, single-center cohort of HIV-infected patients. ART regimens including non-nucleoside reverse transcriptase inhibitors (NNRTI), protease inhibitors (PI), or integrase strand transfer inhibitors (INSTI) from patients who achieved long-term (≥6-month duration) virological suppression (HIV-RNA < 400 copies/mL) from January 1998 to June 2014 were analyzed. The impact of ART composition on the changes of the CD4/CD8 T-cell ratio was modeled using a mixed linear approach with adjustment for possible confounders. A total of 1068 ART regimens from 570 patients were analyzed. Mean (SD) age of the patients was 42.15 (10.68) years and 276 (48.42%) had hepatitis C virus (HCV) coinfection. Five hundred fifty-eight (52.25%) regimens were PI-based, 439 (40.10%) NNRTI-based, and 71 (6.65%) INSTI-based; 487 (45.60%) were initial regimens, 476 (44.57%) simplification, and 105 (9.83%) salvage regimens. Median (IQR) number of regimens was 1 (1-2) per patient, of 29 (14-58) months duration, and 4 (3-7) CD4/CD8 measurements per regimen. The median baseline CD4/CD8 ratio was 0.42, 0.50, and 0.54, respectively, with the PI-, NNRTI-, and INSTI-based regimens (P = 0.0073). Overall median (IQR) increase of CD4/CD8 ratio was 0.0245 (-0.0352-0.0690) per year, and a CD4/CD8 ratio ≥1 was achieved in 19.35% of the cases with PI-based, 25.97% with NNRTI-based, and 22.54% with INSTI-based regimens (P = 0.1406). In the adjusted model, the mean CD4/CD8 T-cell ratio increase was higher with NNRTI-based regimens compared for PI-based (estimated coefficient for PI [95% CI], -0.0912 [-0.1604 to -0.0219], P = 0.009). Also, a higher CD4/CD8 baseline ratio was associated with higher CD4/CD8 increase in the adjusted model (P = 0.001); by contrast, higher age (P = 0.020) and simplification of ART regimen (P = 0.003) had a negative impact on the CD4/CD8 ratio. Antiretroviral regimen composition has a differential impact on the CD4/CD8 T-cell ratio; NNRTI-based regimens are associated with enhanced CD4/CD8 T-cell ratio recovery compared to PI-based antiretroviral regimens.

Efficacy of generic highly active antiretroviral therapy in HIV-1 infected individuals in Nigeria

CD4 T lymphocyte and plasma HIV RNA parameters have been used to monitor disease progression, and predict clinical course in HIV infection. Initial evaluation of these parameters was conducted in the western countries where accessible ARVs, circulating HIV subtypes and mode of transmission are different from the situation in Nigeria. This study appraised these parameters, and efficacy of generic ARVs. Consenting 106 HIV infected ARV naïve patients were enrolled. CD4 T lymphocyte and plasma HIV RNA levels were determined at interval for 24 months. Ninety eight (92.5%) of the patients who completed the follow up in strict adherence to therapy guideline were included in the analysis. Baseline median CD4 T lymphocyte increased from 114 (Range: 6-330) to highest 357 (Range: 15-1036) cells/ μ L at 18 months of therapy, while baseline median plasma viral RNA declined from 4.6 (Range: 2.6-6.0) Log10 copies/mL to undetectable level within three months of therapy. Significant CD4 T-cell restoration and plasma viral RNA decline in the study population demonstrate efficacy of the generic HAART. The importance of combined use of both parameters for evaluation of immunologic and virologic responses to ART was confirmed.

Early Initiation Rather Than Prolonged Duration of Antiretroviral Therapy in HIV Infection Contributes to the Normalization of CD8 T-Cell Counts

BACKGROUND

CD8 T-cell counts remain elevated in human immunodeficiency virus (HIV) infection even after long-term antiretroviral therapy (ART), which is associated with an increased risk of non-AIDS-related events. We assessed the impact of ART initiation in early versus chronic HIV infection on trajectories of CD8 cell counts over time.

METHODS

Of 280 individuals enrolled during primary HIV infection (PHI), 251 were followed up for 24 months; 84 started ART before 6 months of infection (eART), 49 started between 6 and 24 months, and 118 remained untreated. Plasma HIV viral load (VL), CD4 and CD8 cell counts were assessed at each study visit. CD8 counts were also examined in 182 age-matched HIV-infected individuals who started ART during chronic infection and maintained undetectable plasma VL for ≥5 years.

RESULTS

At PHI baseline, higher CD8 cell counts were associated with more recent infection (P = .02), higher CD4 cell counts (P < .001), and higher VL (P < .001). The CD8 count in the eART group decreased from 797 to 588 cells/µL over 24 months (P < .001), to a level lower than that in untreated PHI (834 cells/µL; P = .004) or in long-term-treated patients with chronic HIV infection (743 cells/µL; P = .047). More prominent CD4 T-cell recovery was observed in the eART group than in the delayed ART group.

CONCLUSIONS

ART initiated in early HIV infection is associated with improved resolution of CD8 T-cell elevation compared with long-term ART initiated in chronic infection. Early ART may help reduce the risk of non-AIDS-related events by alleviating this elevation.

Association of microbial translocation biomarkers with clinical outcome in controllers HIV-infected patients

BACKGROUND

A proportion of patients who spontaneously control viral load (controllers) experienced clinical progression. We hypothesized that microbial translocation would independently determine the rate of disease progression in controllers.

METHODS

sCD14, lipopolysaccharide-binding protein (LBP) and EndoCab levels were assessed in 114 antiretroviral-naive patients with CD4(+) T cells above 500 cells/μl (including 63 controllers and 51 noncontrollers). The independent predictive value of these markers on time to progression to the combined endpoint of AIDS, non-AIDS event, initiation of combination antiretroviral therapy (cART) or CD4(+) cell count less than 500 cells/μl was assessed using a Cox regression model.

RESULTS

Most of the patients progressed to a combined endpoint (60%). Clinical progression in controllers was significantly lower than in noncontrollers (P = 0.02). Controllers with lower than the median baseline CD4(+) T-cell count and higher than the median baseline viral load, sCD14 and EndoCab levels had a worse prognosis (P < 0.0001, P = 0.007, P = 0.05 and P = 0.012), while noncontrollers with higher than the median baseline LBP level also had a worse prognosis (P = 0.019). sCD14 and LBP increased and EndoCab decreased over time [from baseline (median values: 1486, 17604 ng/ml and 68 MMU/ml, respectively, to the date of event or the last determination (median values: 1663, 20230 ng/ml and 49 MMU/ml), respectively] in controllers (P = 0.04, 0.08 and 0.0006, respectively).

CONCLUSION

Microbial translocation seems to be an important determinant of clinical progression in HIV-infected controllers independently of viremia. Measures to improve the intestinal mucosa damage or decrease translocation could influence the outcome in these patients.

Course and Clinical Significance of CD8+ T-Cell Counts in a Large Cohort of HIV-Infected Individuals

OBJECTIVES

To examine trajectories of CD8(+) T-cell counts before and after combination antiretroviral therapy (cART) in human immunodeficiency virus (HIV)-infected individuals and associations with mortality.

METHODS

CD8(+) T-cell counts were measured in 3882 HIV-infected individuals who received care in Copenhagen during 1995-2012. Reference values were obtained from 1230 persons from the background population. Mortality rate ratios were estimated by Poisson regression.

RESULTS

CD8(+) T-cell counts were elevated during untreated HIV infection and remained elevated through 10 years of cART. A slight drop of 130 cells/µL (interquartile range, -160 to 410 cells/μL) in the median CD8(+) T-cell count was observed after cART initiation. CD8(+) T-cell counts stabilized at approximately 900 cells/µL (95th percentile of the background population, 835 cells/µL). Markedly elevated CD8(+) T-cell counts at cART initiation were associated with a poor increase in the CD4(+) T-cell count (relative risk, 2.22; 95% confidence interval [CI], 1.42-3.48). Individuals with a CD8(+) T-cell count of <500 cells/µL 1 year after cART initiation had an increased mortality rate (mortality rate ratio, 1.73; 95% CI, 1.29-2.32) and a higher proportion of deaths attributable to AIDS-related conditions, compared with individuals with CD8(+) T-cell counts of ≥500 cells/µL. After receiving cART for 10 years, a CD8(+) T-cell count of >1500 cells/µL was associated with increased non-AIDS-related mortality (mortality rate ratio, 1.82; 95% CI, 1.09-3.22), compared with a CD4(+) T-cell count of 500-1500 cells/µL.

CONCLUSIONS

CD8(+) T-cell counts are elevated during HIV infection and do not normalize despite long-term cART. Low CD8(+) T-cell counts are associated with increased AIDS-related mortality. Marked elevations in CD8(+) T-cell counts after long-term cART are associated with increased non-AIDS-related mortality.

Innate DNA sensing is impaired in HIV patients and IFI16 expression correlates with chronic immune activation

The innate immune system has been recognized to play a role in the pathogenesis of HIV infection, both by stimulating protective activities and through a contribution to chronic immune activation, the development of immunodeficiency and progression to AIDS. A role for DNA sensors in HIV recognition has been suggested recently, and the aim of the present study was to describe the influence of HIV infection on expression and function of intracellular DNA sensing. Here we demonstrate impaired expression of interferon-stimulated genes in responses to DNA in peripheral blood monuclear cells from HIV-positive individuals, irrespective of whether patients receive anti-retroviral treatment. Furthermore, we show that expression levels of the DNA sensors interferon-inducible protein 16 (IFI16) and cyclic guanosine monophosphate-adenosine monophosphate synthase were increased in treatment-naive patients, and for IFI16 expression was correlated with high viral load and low CD4 cell count. Finally, our data demonstrate a correlation between IFI16 and CD38 expression, a marker of immune activation, in CD4(+) central and effector memory T cells, which may indicate that IFI16-mediated DNA sensing and signalling contributes to chronic immune activation. Altogether, the present study demonstrates abnormal expression and function of cytosolic DNA sensors in HIV patients, which may have implications for control of opportunistic infections, chronic immune activation and T cell death.

Immunological function restoration with lopinavir/ritonavir versus efavirenz containing regimens in HIV-infected patients: a randomized clinical trial

CD4(+) count increase has been reported to be different with lopinavir/r (LPV/r) and efavirenz (EFV)-containing regimens. The different effect of these two regimens on other immune function parameters and the relationship with the gain of CD4(+) count have not been assessed in a randomized clinical trial. Fifty antiretroviral treatment (cART) naïve HIV-infected individuals were randomized to receive LPV/r or EFV both with tenofovir/emtricitabine for 48 weeks. A substudy of immunological function restoration was performed in 22 patients (LPV/r n=10 and EFV n=12). Activation, thymic function, apoptosis, senescence, exhaustion, Treg cells, interleukin (IL)-7-receptor/IL-7 system, thymic volume, and lymphoid tissue fibrosis were evaluated at baseline and at week 48. Both groups experienced a CD4(+) count increase that was higher in the EFV group (ΔCD4(+) 88 vs. 315 cells/μl LPV/r vs. EFV, respectively, p<0.001). Despite this difference in CD4(+) gain, the change in other immune function parameters was similar in both treatment groups. Most of parameters evaluated tended to normalize after 48 weeks of cART. A significant decrease in levels of activation, senescence, exhaustion, and apoptosis on CD4(+) and CD8(+) T cells (p<0.001 for all) and a significant increase in markers of thymic function, IL-7 receptor, and in the levels of central memory CD4(+) T cells and naive subsets of CD8(+) T cells (p<0.001 for all) with respect to baseline values were observed without any difference between groups. These data indicate that the differences in CD4(+) gain with different cART regimens are not immunologically meaningful and might explain the similar clinical efficacy of these regimens.

Impact of HIV on CD8+ T cell CD57 expression is distinct from that of CMV and aging

Background

Chronic antigenic stimulation by cytomegalovirus (CMV) is thought to increase “immunosenesence” of aging, characterized by accumulation of terminally differentiated CD28- CD8+ T cells and increased CD57, a marker of proliferative history. Whether chronic HIV infection causes similar effects is currently unclear.

Methods

We compared markers of CD8+ T cell differentiation (e.g., CD28, CD27, CCR7, CD45RA) and CD57 expression on CD28- CD8+ T cells in healthy HIV-uninfected adults with and without CMV infection and in both untreated and antiretroviral therapy (ART)-suppressed HIV-infected adults with asymptomatic CMV infection.

Results

Compared to HIV-uninfected adults without CMV (n = 12), those with asymptomatic CMV infection (n = 31) had a higher proportion of CD28-CD8+ T cells expressing CD57 (P = 0.005). Older age was also associated with greater proportions of CD28-CD8+ T cells expressing CD57 (rho: 0.47, P = 0.007). In contrast, untreated HIV-infected CMV+ participants (n = 55) had much lower proportions of CD28- CD8+ cells expressing CD57 than HIV-uninfected CMV+ participants (P<0.0001) and were enriched for less well-differentiated CD28- transitional memory (T_TR) CD8+ T cells (P<0.0001). Chronically HIV-infected adults maintaining ART-mediated viral suppression (n = 96) had higher proportions of CD28-CD8+ T cells expressing CD57 than untreated patients (P<0.0001), but continued to have significantly lower levels than HIV-uninfected controls (P = 0.001). Among 45 HIV-infected individuals initiating their first ART regimen, the proportion of CD28-CD8+ T cells expressing CD57 declined (P<0.0001), which correlated with a decline in percent of transitional memory CD8+ T cells, and appeared to be largely explained by a decline in CD28-CD57- CD8+ T cell counts rather than an expansion of CD28-CD57+ CD8+ T cell counts.

Conclusions

Unlike CMV and aging, which are associated with terminal differentiation and proliferation of effector memory CD8+ T cells, HIV inhibits this process, expanding less well-differentiated CD28- CD8+ T cells and decreasing the proportion of CD28- CD8+ T cells that express CD57.

Synthetic HIV-1 matrix protein p17-based AT20-KLH therapeutic immunization in HIV-1-infected patients receiving antiretroviral treatment: A phase I safety and immunogenicity study

BACKGROUND

Therapeutic vaccination is a promising novel approach to treat HIV-1 infected people by boosting or redirecting immune system to neutralize critical HIV-1 antigens whose biological effects are relevant in the context of viral pathogenesis. With the aim to induce neutralizing antibodies to the matrix protein p17 we have developed a peptide-based immunogen (AT20-KLH) and evaluated its safety and immunogenicity.

METHODOLOGY

Twenty four asymptomatic HAART-treated HIV-1+ patients were enrolled in a phase I clinical study and were randomized to three groups: 2 groups were treated with five IM injection (Arm A: 25μg/inoculation; Arm B: 100μg/inoculation) at day (D) D0, D28, D56, D84 and D112; the control group (Arm C) were not injected. Safety was assessed by monitoring local and systemic adverse events (AEs), recorded till D168. Evaluation of immunogenicity was by titering antibodies at D0, D35, D56, D63, D84, D91, D112, D140 and D168 using ELISA.

RESULTS

In all, 105 local and systemic AEs were reported across the three groups. Most were mild and resolved without sequelae. Also the few unsolicited events, deemed unrelated to the study vaccines, caused no problems. No significant changes in the routine laboratory parameters, CD4 T-cell count or HIV-1 viremia were found. At the time of enrollment 23 out of 24 patients had no anti-AT20 antibodies, whereas 11 exhibited anti-p17 antibodies. Irrespective of the presence of preimmunization antibodies, all subjects developed high titers of anti-AT20 antibodies (GM 9775) in response to both AT20-KLH doses. These antibodies were also capable of recognizing AT20 within the p17 framework.

CONCLUSIONS

The AT20 peptide-based approach has allowed to redirect HAART-treated patients' humoral responses toward a previously untargeted hotspot of functional activity. Overall, the tested AT20-KLH doses were safe and well tolerated, supporting further exploration of AT20-KLH as an HIV-1 therapeutic vaccine candidate.

Predictors of CD4:CD8 ratio normalization and its effect on health outcomes in the era of combination antiretroviral therapy

Background

HIV leads to CD4:CD8 ratio inversion as immune dysregulation progresses. We examined the predictors of CD4:CD8 normalization after combination antiretroviral therapy (cART) and determined whether normalization is associated with reduced progression to AIDS-defining illnesses (ADI) and death.

Methods

A Canadian cohort of HIV-positive adults with CD4:CD8<1.2 prior to starting cART from 2000–2010 were analyzed. Predictors of (1) reaching a CD4:CD8 ≥1.2 on two separate follow-up visits >30 days apart, and (2) ADI and death from all causes were assessed using adjusted proportional hazards models.

Results

4206 patients were studied for a median of 2.77 years and 306 (7.2%) normalized their CD4:CD8 ratio. Factors associated with achieving a normal CD4:CD8 ratio were: baseline CD4+ T-cells >350 cells/mm³, baseline CD8+ T-cells <500 cells/mm³, time-updated HIV RNA suppression, and not reporting sex with other men as a risk factor. There were 213 ADIs and 214 deaths in 13476 person-years of follow-up. Achieving a normal CD4:CD8 ratio was not associated with time to ADI/death.

Conclusions

In our study, few individuals normalized their CD4:CD8 ratios within the first few years of initiating modern cART. This large study showed no additional short-term predictive value of the CD4:CD8 ratio for clinical outcomes after accounting for other risk factors including age and HIV RNA.

Effects of tuberculosis on the kinetics of CD4(+) T cell count among HIV-infected patients who initiated antiretroviral therapy early after tuberculosis treatment

The effects of tuberculosis (TB) on the kinetics of CD4(+) T cells among HIV-infected individuals with early combination antiretroviral therapy (cART) after TB therapy initiation are poorly characterized. We conducted a case-control study with 15 HIV-TB-coinfected patients who initiated TB treatment and early cART, and 30 controls without TB who had similar CD4(+) T cell counts and viral loads at the time of starting cART. We compared the rate of CD4(+) T cell increase for 5 years after cART. The time to CD4(+) T cell increase >250 cells/mm(3) was significantly slower in HIV-TB-coinfected patients (p=0.015, by log rank test). HIV-TB-coinfected patients had significantly lower median CD4(+) T cell counts at 5 years after cART (p=0.048). The difference in CD4(+) T cell increase was observed only during the first 6 months after cART initiation (p=0.002). These data suggest that TB slows the rate of CD4(+) T cell recovery at an early period after cART. The effects of TB on the long-term immunity of HIV-infected patients should be further evaluated.

In vitro effects of the CCR5 inhibitor maraviroc on human T cell function

BACKGROUND

Several potential immunological benefits have been observed during treatment with the CC chemokine receptor 5 (CCR5) antagonist maraviroc, in addition to its antiviral effect. Our objective was to analyse the in vitro effects of CCR5 blockade on T lymphocyte function and homeostasis.

METHODS

Peripheral blood mononuclear cells (PBMCs) from both HIV-negative (n=28) and treated HIV-positive (n=27) individuals were exposed in vitro to different concentrations of maraviroc (0.1-100 μM). Effects on T cell activation were analysed by measuring the expression of the CD69, CD38, HLA-DR and CD25 receptors as well as CCR5 density using flow cytometry. Spontaneous and chemokine-induced chemotaxis were measured by transwell migration assays, and polyclonal-induced proliferation was assessed by a lymphoproliferation assay and carboxyfluorescein succinimidyl ester staining.

RESULTS

Maraviroc increases CCR5 surface expression on activated T cells, even at low doses (0.1 μM). Slight differences were detected in the frequency and mean fluorescence intensity of activation markers at high concentrations of maraviroc. Expression of CD25, CD38 and HLA-DR tended to decrease in both CD4+ and CD8+ T lymphocytes, whereas expression of CD69 tended to increase. Maraviroc clearly inhibits T cell migration induced by chemokines in a dose-dependent manner. Moreover, at 100 μM, maraviroc tends to inhibit T cell proliferation.

CONCLUSIONS

These data showed that in vitro exposure to maraviroc decreases some activation expression markers on T lymphocytes and also migration towards chemoattractants. These results support the additional immunological effects of CCR5 blockade and suggest that maraviroc might have potential capacity to inhibit HIV-associated chronic inflammation and activation, both by directly affecting T cell activation and by reducing entrapment of lymphocytes in lymph nodes.

HIV antiretroviral medications and hepatotoxicity

PURPOSE OF REVIEW

This review considers the differential diagnosis, pathophysiology and risk of hepatotoxicity of specific antiretroviral medications.

RECENT FINDINGS

Currently prescribed antiretroviral medications are associated with an incidence of grade 3/4 liver enzyme elevation of less than 5%. Clinically apparent hepatotoxicity rates are much lower. The risk of adverse events with combination HIV and hepatitis C virus treatments is low, assuming that several nucleosides including didanosine and stavudine are avoided.

SUMMARY

Irrespective of the HIV antiretroviral regimen prescribed, careful observation of liver function and enzymes is advised, especially in those with comorbid liver disease. The majority of patients do not experience treatment-limiting liver toxicities, achieve virological suppression, and realize immunological restoration.

Therapeutic vaccines against HIV infection

Resistance to medication, adverse effects in the medium-to-long-term and cost all place important limitations on lifelong adherence to combined antiretroviral therapy (cART). In this context, new therapeutic alternatives to 'cART for life' in HIV-infected patients merit investigation. Some data suggest that strong T cell-mediated immunity to HIV can indeed limit virus replication and protect against CD4 depletion and disease progression. The combination of cART with immune therapy to restore and/or boost immune-specific responses to HIV has been proposed, the ultimate aim being to achieve a 'functional cure'. In this scenario, new, induced, HIV-specific immune responses would be able to control viral replication to undetectable levels, mimicking the situation of the minority of patients who control viral replication without treatment and do not progress to AIDS. Classical approaches such as whole inactivated virus or recombinant protein initially proved useful as therapeutic vaccines. Overall, however, the ability of these early vaccines to increase HIV-specific responses was very limited and study results were discouraging, as no consistent immunogenicity was demonstrated and there was no clear impact on viral load. Recent years have seen the development of new approaches based on more innovative vectors such as DNA, recombinant virus or dendritic cells. Most clinical trials of these new vectors have demonstrated their ability to induce HIV-specific immune responses, although they show very limited efficacy in terms of controlling viral replication. However, some preliminary results suggest that dendritic cell-based vaccines are the most promising candidates. To improve the effectiveness of these vaccines, a better understanding of the mechanisms of protection, virological control and immune deterioration is required; without this knowledge, an efficacious therapeutic vaccine will remain elusive.

Effects of antiretroviral therapy on immune function of HIV-infected adults with pulmonary tuberculosis and CD4+ >350 cells/mm3

BACKGROUND

Human immunodeficiency virus (HIV)-tuberculosis coinfection is associated with heightened immune activation, viral replication, and T cell dysfunction. We compared changes in T cell activation and function between patients receiving concurrent treatment for HIV-tuberculosis coinfection and those receiving treatment for tuberculosis alone.

METHODS

HIV-infected adults with tuberculosis and CD4(+) T cell counts >350 cells/mm(3) were randomized to receive tuberculosis treatment alone (control arm; n = 36) or 6 months of antiretroviral therapy (ART) concurrent with tuberculosis treatment (intervention arm; n = 38). HIV viral load, T cell subsets, T cell activation, and cytokine production were measured at enrollment and every 3 months for 12 months.

RESULTS

Differences in absolute CD4(+) and CD8(+) T cell counts were not observed between arms. Viral load was reduced while participants received ART; control patients maintained viral load at baseline levels. Both arms had significant reductions in T cell expression of CD38 and HLA-DR. Interferon-γ production in response to mitogen increased significantly in the intervention arm.

CONCLUSIONS

In HIV-infected adults with tuberculosis and CD4(+) T cell counts >350 cells/mm(3), both tuberculosis treatment and concurrent HIV-tuberculosis treatment reduce T cell activation and stabilize T cell counts. Concurrent ART with tuberculosis treatment does not provide additional, sustained reductions in T cell activation among individuals with preserved immunologic function.

CD8 T-Cell Responses before and after Structured Treatment Interruption in Ugandan Adults Who Initiated ART with CD4 T Cells <200 Cell/μL: The DART Trial STI Substudy

Objective. To better understand attributes of ART-associated HIV-induced T-cell responses that might be therapeutically harnessed. Methods. CD8(+) T-cell responses were evaluated in some HIV-1 chronically infected participants of the fixed duration STI substudy of the DART trial. Magnitudes, breadths, and functionality of IFN-γ and Perforin responses were compared in STI (n = 42) and continuous treatment (CT) (n = 46) before and after a single STI cycle when the DART STI trial was stopped early due to inferior clinical outcome in STI participants. Results. STI and CT had comparable magnitudes and breadths of monofunctional CD8(+)IFNγ(+) and CD8(+)Perforin(+) responses. However, STI was associated with significant decline in breadth of bi-functional (CD8(+)IFNγ(+)Perforin(+)) responses; P = .02, Mann-Whitney test. Conclusions. STI in individuals initiated onto ART at <200 CD4(+) T-cell counts/μl significantly reduced occurrence of bifunctional CD8(+)IFNγ(+)/Perforin(+) responses. These data add to others that found no evidence to support STI as a strategy to improve HIV-specific immunity during ART.

HIV-1 matrix protein p17: a candidate antigen for therapeutic vaccines against AIDS

The success in the development of anti-retroviral therapies (HAART) that contain human immunodeficiency virus type 1 (HIV-1) infection is challenged by the cost of this lifelong therapy and by its toxicity. Immune-based therapeutic strategies that boost the immune response against HIV-1 proteins or protein subunits have been recently proposed to control virus replication in order to provide protection from disease development, reduce virus transmission, and help limit the use of anti-retroviral treatments. HIV-1 matrix protein p17 is a structural protein that is critically involved in most stages of the life cycle of the retrovirus. Besides its well established role in the virus life cycle, increasing evidence suggests that p17 may also be active extracellularly in deregulating biological activities of many different immune cells that are directly or indirectly involved in AIDS pathogenesis. Thus, p17 might represent a promising target for developing a therapeutic vaccine as a contribution to combating AIDS. In this article we review the biological characteristics of HIV-1 matrix protein p17 and we describe why a synthetic peptide representative of the p17 functional epitope may work as a vaccine molecule capable of inducing anti-p17 neutralizing response against p17 derived from divergent HIV-1 strains.

HIV reservoir size and persistence are driven by T cell survival and homeostatic proliferation

HIV persists in a reservoir of latently infected CD4(+) T cells in individuals treated with highly active antiretroviral therapy (HAART). Here we identify central memory (T(CM)) and transitional memory (T(TM)) CD4(+) T cells as the major cellular reservoirs for HIV and find that viral persistence is ensured by two different mechanisms. HIV primarily persists in T(CM) cells in subjects showing reconstitution of the CD4(+) compartment upon HAART. This reservoir is maintained through T cell survival and low-level antigen-driven proliferation and is slowly depleted with time. In contrast, proviral DNA is preferentially detected in T(TM) cells from aviremic individuals with low CD4(+) counts and higher amounts of interleukin-7-mediated homeostatic proliferation, a mechanism that ensures the persistence of these cells. Our results suggest that viral eradication might be achieved through the combined use of strategic interventions targeting viral replication and, as in cancer, drugs that interfere with the self renewal and persistence of proliferating memory T cells.

Assessment of migration of HIV-1-loaded dendritic cells labeled with 111In-oxine used as a therapeutic vaccine in HIV-1-infected patients

Monocyte-derived dendritic cells (DCs) loaded with heat-inactivated HIV are used in therapeutic immunizations. It is not known whether they migrate in vivo to lymph nodes. We used an 111In-oxine-labeled DC (ILDC) method to visualize the migration of DCs. The activity, time and incubation medium were investigated to obtain the highest cellular viability and radiolabeling yield. A trypan-blue exclusion test was used to determine the cellular viability. In five patients, 2 × 106 ILDCs were injected subcutaneously in the arm. An initial dynamic study was performed during the first 5 min after injection. This was followed by static acquisitions at several time points, using a high-resolution (general electric) γ-camera and quantifying the activity at regions of interest drawn on the injection point. The sensitivity of the γ-camera was evaluated. The highest number of viable DCs (>83%) and the best radiolabeling yield (>70%) were obtained with 1.11 MBq 111In-oxine, after 10 min of incubation at 37°C in sodium chloride solution 0.9%. We did not observe migration of ILDCs to local lymph nodes in any patient. However, focal uptake at the place of injection continued during the study period. We observed a higher than expected loss of activity from the injection point (median At/A0 = 0.60 at day 2), which correlated with an increase in total cytotoxic T lymphocytes (CD8+ and granzyme B+ cells) in the lypmphoid tissue observed after immunization (R2 = 0.92, p = 0.03). If more than 20,000 ILDCs had migrated, they could have been detected. In future trials, a higher number of DCs or alternative methods should be used to assess the migration of DCs to lymph nodes.

Influence of alternative thresholds for initiating HIV treatment on quality-adjusted life expectancy: a decision model

BACKGROUND

The optimal threshold for initiating HIV treatment is unclear.

OBJECTIVE

To compare different thresholds for initiating HIV treatment.

DESIGN

A validated computer simulation was used to weigh important harms from earlier initiation of antiretroviral therapy (toxicity, side effects, and resistance accumulation) against important benefits (decreased HIV-related mortality).

DATA SOURCES

Veterans Aging Cohort Study (5742 HIV-infected patients and 11 484 matched uninfected controls) and published reports.

TARGET POPULATION

Individuals with newly diagnosed chronic HIV infection and varying viral loads (10,000, 30,000, 100,000, and 300,000 copies/mL) and ages (30, 40, and 50 years).

TIME HORIZON

Unlimited.

PERSPECTIVE

Societal.

INTERVENTION

Alternative thresholds for initiating antiretroviral therapy (CD4 counts of 200, 350, and 500 cells/mm3).

OUTCOME MEASURES

Life-years and quality-adjusted life-years (QALYs).

RESULTS OF BASE-CASE ANALYSIS

Although the simulation was biased against earlier treatment initiation because it used an upper-bound assumption for therapy-related toxicity, earlier treatment increased life expectancy and QALYs at age 30 years regardless of viral load (life expectancies with CD4 initiation thresholds of 500, 350, and 200 cells/mm3 were 18.2 years, 17.6 years, and 17.2 years, respectively, for a viral load of 10,000 copies/mL and 17.3 years, 15.9 years, and 14.5 years, respectively, for a viral load of 300,000 copies/mL), and increased life expectancies at age 40 years if viral loads were greater than 30 000 copies/mL (life expectancies were 12.5 years, 12.0 years, and 11.4 years, respectively, for a viral load of 300,000 copies/mL).

RESULTS OF SENSITIVITY ANALYSIS

Findings favoring early treatment were generally robust.

LIMITATIONS

Results favoring later treatment may not be valid. The findings may not be generalizable to women.

CONCLUSION

This simulation suggests that earlier initiation of combination antiretroviral therapy is often favored compared with current recommendations.

Should antiretroviral therapy be started earlier?

Current treatment guidelines recommend that antiretroviral therapy be deferred until the CD4 count has fallen into the 200 to 350 cells/mm(3) range. However, treatment has become simpler, less toxic, and more forgiving of missed doses. Longer-term follow-up data from clinical cohorts are now showing better outcomes when therapy is started at higher CD4 cell counts. Therapy initiated early has better virologic and immunologic responses, is better tolerated, and is cost-effective. Recent developments and clinical data support a return to earlier initiation of therapy.

Secretion of antiretroviral chemokines by human cells cultured with acyclic nucleoside phosphonates

Acyclic nucleoside phosphonates are novel class of clinically broadly used antivirotics effective against replication of both DNA viruses and retroviruses including human immunodeficiency virus (HIV). We have investigated their in vitro effects on immune defence mechanisms in human peripheral blood mononuclear cells, with the main emphasis on expression of cytokines which are able to suppress the entry of HIV in cells. Included in the study were prototype acyclic nucleoside phosphonates, i.e. 9-[2-(phosphonomethoxy)ethyl]adenine (PMEA; adefovir), 9-[2-(phosphonomethoxy)ethyl]-2,6-diaminopurine (PMEDAP), (R)-and (S)-enantiomers of 9-[2-(phosphonomethoxy)propyl]adenine [(R)-PMPA; tenofovir] and [(S)-PMPA], and of 9-[2-(phosphonomethoxy)propyl]-2,6-diaminopurine [(R)-PMPDAP] and [(S)-PMPDAP], and their N(6)-substituted derivatives. Some of the compounds were found to substantially enhance secretion of chemokines such as macrophage inflammatory protein-1alpha (MIP-alpha/CCL3), and "regulated on activation of normal T cell expressed and secreted" (RANTES/CCL5). Secretion of MIP-1beta/CCL4 was only marginally increased, whereas production of interleukin-16 (IL-16) and interferon-gamma (IFN-gamma) remained uninfluenced. The most effective proved to be the N(6)-cyclooctyl-PMEDAP, N(6)-isobutyl-PMEDAP, N(6)-pyrrolidino-PMEDAP, N(6)-cyclopropyl-(R)-PMPDAP, and N(6)-cyclopentyl-(R)-PMPDAP derivatives. Remarkably enhanced secretion of chemokines was reached within 2-4 h of the cell culture, and was observed at concentration of 2-5 microM. It may be suggested that acyclic nucleoside phosphonates represent a new generation of antivirotics with combined antimetabolic and therapeutically prospective immunostimulatory properties.

Local tumor control and toxicity in HIV-associated anal carcinoma treated with radiotherapy in the era of antiretroviral therapy

PURPOSE

To investigate the outcome of HIV-seropositive patients under highly active antiretroviral treatment (HAART) with anal cancer treated with radiotherapy (RT) alone or in combination with standard chemotherapy (CT).

PATIENTS AND METHODS

Clinical outcome of 81 HIV-seronegative patients (1988-2003) and 10 consecutive HIV-seropositive patients under HAART (1997-2003) that were treated with 3-D conformal RT of 59.4 Gy and standard 5-fluorouracil and mitomycin-C were retrospectively analysed. 10 TNM-stage and age matched HIV-seronegative patients (1992-2003) were compared with the 10 HIV-seropositive patients. Pattern of care, local disease control (LC), overall survival (OS), cancer-specific survival (CSS), and toxicity were assessed.

RESULTS

RT with or without CT resulted in complete response in 100% of HIV-seropositive patients. LC was impaired compared to matched HIV-seronegative patients after a median follow-up of 44 months (p = 0.03). OS at 5 years was 70% in HIV-seropositive patients receiving HAART and 69% in the matched controls. Colostomy-free survival was 70% (HIV+) and 100% (matched HIV-) and 78% (all HIV-). No HIV-seropositive patient received an interstitial brachytherapy boost compared to 42% of all HIV-seronegative patients and adherence to chemotherapy seemed to be difficult in HIV-seropositive patients. Acute hematological toxicity reaching 50% was high in HIV-seropositive patients receiving MMC compared with 0% in matched HIV-seronegative patients (p = 0.05) or 12% in all HIV-seronegative patients. The rate of long-term side effects was low in HIV-seropositive patients.

CONCLUSION

Despite high response rates to organ preserving treatment with RT with or without CT, local tumor failure seems to be high in HIV-positive patients receiving HAART. HIV-seropositive patients are subject to treatment bias, being less likely treated with interstitial brachytherapy boost probably due to HIV-infection, and they are at risk to receive less chemotherapy.

Dynamics of T cells subsets and lymphoproliferative responses during structured treatment interruption cycles and after definitive interruption of HAART in early chronic HIV type-1-infected patients

Little is known about the consequences of short cycles of structured treatment interruption or definitive interruption of HAART for both T cell subset dynamics and T lymphoproliferative responses (LPR). Immunological follow-up was performed in 45 early chronical HIV-1-infected patients during short STI cycles during the first 12 weeks after the definitive interruption of HAART (DTI) and, thereafter, until VL reached a plateau. During STI cycles, CD8(+), CD8(+), CD28(+), activation markers and naive CD4(+) T cells increased significantly (p < 0.0001), while both naive CD8(+) and memory CD4(+) T cells decreased. During DTI, CD8(+) CD28(+) T cells fell and CD4(+) naive T cells stabilized and the rest of the T cell subsets presented changes similar to those during STI cycles. Despite a transient increase in LPR to recall antigens and HIV proteins during STI cycles, LPR to polyclonal stimuli and pathogens decreased over the study. Differences in T cell subset dynamics and LPR observed throughout the study suggest that multiple exposures to low levels of antigen could improve the immune system, mainly by driving T cell maturation. Conversely, higher and longer viral replication after cessation of HAART overwhelms the immune system. These data may help to guide future immune-based therapies.

Changes in T-cell subpopulations during four years of suppression of HIV-1 replication in patients with advanced disease

We compared the number/percentages of naive and memory CD4+ T-cells, CD38+ CD8+ T-cells, and CD28+ CD4+ and CD28+ CD8+ T-cells in patients with advanced HIV disease (baseline CD4+ count < 100) with those with less advanced (baseline CD4+ cell count > 100) HIV disease during 4 years of suppressive highly active antiretroviral therapy. This prospective, longitudinal study included 30 treatment-naive patients and 32 controls. Advanced HIV-infected patients (n = 13) gained more CD4+ T-cells than less advanced patients (n = 11) at 1 month (median: 60 vs. 36 microL(-1)), 3 months (86 vs. 14), 6 months (111 vs. 23), 12 months (174 vs. 47), 24 months (162 vs. 72) and 48 months (257 vs. 123) (P = 0.15, P < 0.001, P = 0.026, P = 0.021, P = 0.1 and P = 0.06, respectively). Advanced patients gained more naive CD4+ T-cells at 48 months compared to less advanced patients (27.3 vs. 11.4%, P = 0.05). The relative gain in memory CD4+ T-cells was greater in advanced vs. less advanced patients at 1 month (median: 6.4 vs. 1.4%), 3 months (4.3 vs. 2.0), 6 months (6.7 vs. 1.6), 12 months (6.9 vs. 2.4), 24 months (7.5 vs. 3.1) and 48 months (11.3 vs. 6.8) (P = 0.002, P = 0.013, P < 0.001, P = 0.004, P = 0.001 and P = 0.015, respectively). At 48 months, CD38+ CD8+ T-cells and naive CD4+ T-cells reached normal values (9.2%, P = 0.869 vs. controls and 47.5%, P = 0.699, respectively) in less advanced patients, as did CD38+ CD8+ T-cells in advanced patients (4.7%, P = 0.309 vs. controls). The kinetics of naive and memory CD4+ T-cell reconstitution is different in less advanced compared to advanced HIV patients.

HIV-specific cellular immune responses are stimulated by structured treatment interruption in chronically HIV-1 infected Koreans

We evaluated the enhancing effect of structured treatment interruptions (STIs) on HIV-specific immunity in chronically HIV-1 infected Korean patients. A prospective case-control study was done with a total of 10 subjects for a period of 26 weeks. Six subjects were on STIs and four subjects were on continuous HAART for comparison. The STI subjects underwent four periods of STIs. For those on STIs, HAART was stopped at week 0 for two weeks, and resumed thereafter for six weeks. Viral load and CD4+/CD8+ T cells were measured by HIV RNA RT-PCR and flow cytometry, and HIV-specific immunity was measured by an ELISPOT assay. HIV-specific cytotoxic T cell immunity was more pronounced in the STI subjects than in the continuous HAART subjects after 26 weeks (p = 0.011). The difference in cytotoxic T cell response in the STI group was more prominent than in the continuous HAART group (p = 0.011). Viral load after 26 weeks was higher in the STI subjects than in the continuous HAART subjects (p = 0.008). An HIV-specific cellular immune response can be stimulated by STIs in chronically HIV-infected Koreans. A larger study is warranted in order to further characterize viral and immunological parameters of treatment with STIs in cases of chronic HIV infection.

Astrocyte activation and apoptosis: their roles in the neuropathology of HIV infection

Astrogliosis is a common neuropathological finding in the brains of HIV infected individuals; both activation and apoptosis of astrocytes are seen. This review aims to discuss the Fas pathway in the context of proliferation and apoptosis of astrocytes during HIV infection, and as a result of astrogliosis, the dysregulation of astrocyte-neuron networks. The presence of molecules reflecting astrocyte activation, which are derived from the solubilization of receptor/ligand from the surface of proliferating astrocytes, in the cerebrospinal fluid may be used to evaluate the degree of brain cell activation during HAART therapy. A better understanding of the molecular pathway(s) leading to increase activation and apoptosis of astrocytes, in parallel with studies conducted to unravel the molecules involved in T-cell apoptosis during HIV infection, may lead to the development of new therapeutic strategies for controlling HIV replication and tissue damage.

Polymorphisms in the interleukin-4 receptor alpha chain gene influence susceptibility to HIV-1 infection and its progression to AIDS

Interleukin (IL) 4 is a key T helper-2 cytokine that downregulates and upregulates CCR5 and CXCR4, respectively, the main coreceptors for HIV. Our objective is to investigate whether single-nucleotide polymorphisms (SNPs) in the IL-4 receptor alpha chain gene (IL4RA) affect HIV infection and its progression to AIDS. The I50V SNP in exon 5 and the haplotypes of six SNPs in exon 12 (E375A, C406R, S411L, S478P, Q551R, and V554I) were studied by polymerase chain reaction and sequencing in 30 HIV+ long-term nonprogressors (LTNP), 36 HIV+ typical progressors (TP), 55 highly exposed but uninfected individuals (EU), 25 EU-sexuals (EU-Sex; mostly women) and 30 EU-hemophiliacs (EU-Hem; hepatitis C virus+), and 97 healthy controls (HC), all Caucasians and lacking CCR5Delta32 homozygosity. V50 homozygosity was increased in LTNP (44%) compared with the other groups [p = 0.005; relative risk ratio = 3.4, 95% confidence interval (CI) = 1.12-10.6, p = 0.03]. The most common (C) exon 12 haplotype, ECSSQV, predominated in all groups, but uncommon (U) haplotypes were increased in HIV+ individuals (n = 64), especially in those (51 of 64) infected via parenteral exposure (35.3%) compared with HC (20.4%) and EU-Hem (18.4%) [p = 0.01; odds ratio (OR) = 2.14, 95% CI = 1.25-3.67, p = 0.01]. EU-Sex also had an increased frequency of U-haplotypes (34.8%) (OR = 2.10, 95% CI = 1.03-4.21, p = 0.01) as well as an increased frequency of CU + UU genotypes (60.9%) compared with HC (38.2%) and EU-Hem (26.6%) (p = 0.043). Distributions of genotypes fitted Hardy-Weinberg equilibrium. Data suggest that V50 homozygosity associates with slow progression and that exon 12 U-haplotypes might be associated with both susceptibility to infection via parenteral route and resistance to infection via sexual exposure. Further studies are required to confirm these findings.