HIV-associated immune activation: from bench to bedside

T cell-mediated Immune response and correlates of inflammation and their relationship with COVID-19 clinical severity: not an intuitive guess

BACKGROUND

Predictors of the outcome of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection remain to be fully determined. We evaluated selected viral characteristics and immunological responses that might predict and/or correlate to the clinical outcome of COVID-19.

METHODS

For individuals developing divergent clinical outcomes, the magnitude and breadth of T cell-mediated responses were measured within 36 h of symptom onset. Peripheral Blood Mononuclear Cells (PBMCs) were subjected to in vitro stimulation with SARS-CoV-2-based peptides. In addition, SARS-CoV-2 sequences were generated by metagenome, and HLA typing was performed using Luminex technology.

FINDINGS

CD4+ T cell activation was negatively correlated with SARS-CoV-2 basal viral load in patients with severe COVID-19 (p = 0·043). The overall cellular immune response, as inferred by the IFN-γ signal, was higher at baseline for patients who progressed to mild disease compared to patients who progressed to severe disease (p = 0·0044). Subjects with milder disease developed higher T cell responses for MHC class I and II-restricted peptides (p = 0·033).

INTERPRETATION

Mounting specific cellular immune responses in the first days after symptom onset, as inferred by IFN-γ magnitude in the ELISPOT assay, may efficiently favor a positive outcome. In contrast, progression to severe COVID-19 was accompanied by stronger cellular immune responses, higher CD4 + T cell activation, and a higher number of in silico predicted high-affinity class I HLA alleles.

Pre-existing cell populations with cytotoxic activity against SARS-CoV-2 in people with HIV and normal CD4/CD8 ratio previously unexposed to the virus

Introduction

HIV-1 infection may produce a detrimental effect on the immune response. Early start of antiretroviral therapy (ART) is recommended to preserve the integrity of the immune system. In fact, people with HIV (PWH) and normal CD4/CD8 ratio appear not to be more susceptible to severe forms of COVID-19 than the general population and they usually present a good seroconversion rate in response to vaccination against SARS-CoV-2. However, few studies have fully characterized the development of cytotoxic immune populations in response to COVID-19 vaccination in these individuals.

Methods

In this study, we recruited PWH with median time of HIV-1 infection of 6 years, median CD4/CD8 ratio of 1.0, good adherence to ART, persistently undetectable viral load, and negative serology against SARS-CoV-2, who then received the complete vaccination schedule against COVID-19. Blood samples were taken before vaccination against COVID-19 and one month after receiving the complete vaccination schedule.

Results

PWH produced high levels of IgG against SARS-CoV-2 in response to vaccination that were comparable to healthy donors, with a significantly higher neutralization capacity. Interestingly, the cytotoxic activity of PBMCs from PWH against SARS-CoV-2-infected cells was higher than healthy donors before receiving the vaccination schedule, pointing out the pre-existence of activated cell populations with likely unspecific antiviral activity. The characterization of these cytotoxic cell populations revealed high levels of Tgd cells with degranulation capacity against SARS-CoV-2-infected cells. In response to vaccination, the degranulation capacity of CD8+ T cells also increased in PWH but not in healthy donors.

Discussion

The full vaccination schedule against COVID-19 did not modify the ability to respond against HIV-1-infected cells in PWH and these individuals did not show more susceptibility to breakthrough infection with SARS-CoV-2 than healthy donors after 12 months of follow-up. These results revealed the development of protective cell populations with broad-spectrum antiviral activity in PWH with normal CD4/CD8 ratio and confirmed the importance of early ART and treatment adherence to avoid immune dysfunctions.

The Many Faces of Immune Activation in HIV-1 Infection: A Multifactorial Interconnection

Chronic immune activation has a significant role in HIV-1 disease pathogenesis and CD4+ T-cell depletion. The causes of chronic inflammation and immune activation are incompletely understood, but they are likely multifactorial in nature, involving both direct and indirect stimuli. Possible explanations include microbial translocation, coinfection, and continued presence of competent replicating virus. In fact, long-term viral suppression treatments are unable to normalize elevated markers of systemic immune activation. Furthermore, high levels of pro-inflammatory cytokines increase susceptibility to premature aging of the immune system. The phenomenon of "inflammaging" has begun to be evident in the last decades, as a consequence of increased life expectancy due to the introduction of cART. Quality of life and survival have improved substantially; however, PLWH are predisposed to chronic inflammatory conditions leading to age-associated diseases, such as inflammatory bowel disease, neurocognitive disorders, cardiovascular diseases, metabolic syndrome, bone abnormalities, and non-HIV-associated cancers. Several approaches have been studied in numerous uncontrolled and/or randomized clinical trials with the aim of reducing immune activation/inflammatory status in PLWH, none of which have achieved consistent results.

Elevated CD4 + T-cell glucose metabolism in HIV+ women with diabetes mellitus

OBJECTIVE

Immune dysfunction and chronic inflammation are characteristic of HIV infection and diabetes mellitus, with CD4 + T-cell metabolism implicated in the pathogenesis of each disease. However, there is limited information on CD4 + T-cell metabolism in HIV+ persons with diabetes mellitus. We examined CD4 + T-cell glucose metabolism in HIV+ women with and without diabetes mellitus.

DESIGN

A case-control study was used to compare CD4 + T-cell glucose metabolism in women with HIV with or without diabetes mellitus.

METHODS

Nondiabetic (HIV+DM-, N = 20) or type 2 diabetic HIV+ women with (HIV+DM+, N  = 16) or without (HIV+DMTx+, N  = 18) antidiabetic treatment were identified from the WIHS and matched for age, race/ethnicity, smoking status and CD4 + cell count. CD4 + T-cell immunometabolism was examined by flow cytometry, microfluidic qRT-PCR of metabolic genes, and Seahorse extracellular flux analysis of stimulated CD4 + T cells.

RESULTS

HIV+DM+ displayed a significantly elevated proportion of CD4 + T cells expressing the immunometabolic marker GLUT1 compared with HIV+DMTx+ and HIV+DM- ( P  = 0.04 and P  = 0.01, respectively). Relative expression of genes encoding key enzymes for glucose metabolism pathways were elevated in CD4 + T cells of HIV+DM+ compared with HIV+DMTx+ and HIV+DM-. T-cell receptor (TCR)-activated CD4 + T cells from HIV+DM+ showed elevated glycolysis and oxidative phosphorylation compared with HIV+DM-.

CONCLUSION

CD4 + T cells from HIV+DM+ have elevated glucose metabolism. Treatment of diabetes mellitus among women with HIV may partially correct CD4 + T-cell metabolic dysfunction.

Combined multi-omics and network pharmacology approach reveals the role of Tripterygium Wilfordii Hook F in treating HIV immunological non-responders

BACKGROUND

The HIV-1 infected immunological non-responders (INRs) are characterized by poor immune reconstitution after long-term treatment. Tripterygium Wilfordii Hook F (TwHF) pill is a traditional Chinese patent drug with extensive immunosuppressive effects and has been clinically proven efficacy in treating INRs.

PURPOSE

The therapeutic mechanism of TwHF pills in the treatment of INRs was investigated by the combined multi-omics analysis on clinical samples and network pharmacology approach.

METHODS

Clinically, the peripheral blood mononuclear cells (PBMC) samples of TwHF-treated INRs from different time points were collected to conduct the transcriptomic and proteomic profiling. Key effector pathways of TwHF were enriched and analyzed by the ingenuity pathway analysis (IPA). Computationally, the TwHF-related compounds were obtained from traditional Chinese medicine databases, and literature search and structural prediction were performed to identify TwHF-related targets. Integrated with the INR-related targets, the 'TwHF-compounds-targets-INR' network was constructed to analyze core effector targets by centrality measurement. Experimentally, the effects of TwHF compounds on the T cells activation and expression of identified targets were evaluated with in vitro cell culture.

RESULTS

33 INRs were included and treated with TwHF pills for 17 (IQR, 12-24) months. These patients experienced rapid growth in the CD4⁺ T cell counts and decreased T cell activation. The multi-omics analysis showed that the interferon (IFN)-signaling pathway was significantly inhibited after taking TwHF pills. The network pharmacology predicted the central role of the signal transducer and activator of transcription 1 (STAT1) in the 'TwHF-compounds-targets-INR' network. Further bioinformatic analysis predicted STAT1 would regulate over 58.8% of identified down-regulated genes. Cell experiments validated that triptolide (TPL) would serve as the major bioactivity compound of TwHF pills to inhibit the immune cell activation, the production of IFN-γ, the expression of downstream IFN-stimulated genes, and the phosphorylation of STAT1.

CONCLUSION

Our research is the first to systemic verify the mechanisms of TwHF in treating INRs. The IFN signaling pathway and the STAT1 would be the major effector targets of TwHF pills in treating INRs. The TPL would be the major bioactive compound to inhibit the IFN response and the phosphorylation of STAT1. Our observations suggest the basis for further application of TPL analogous in treating INRs.

Study protocol: an observational study of distress, immune function and persistent pain in HIV

INTRODUCTION

Many people with HIV report both distress and pain. The relationship between distress and pain is bidirectional, but the mechanisms by which distress exacerbates pain are unclear. The inflammatory response to challenge (inflammatory reactivity, IR) may be a partial mediator, given that neuroimmune interactions provide a substrate for IR to also influence neurological reactivity and, thus, pain-related neural signalling. This prospective, observational, case-control study will characterise the relationships between distress, IR, pain-related signalling as captured by induced secondary hyperalgesia (SH), and pain, in people with HIV who report persistent pain (PP) (cases) or no pain (controls).

METHODS AND ANALYSIS

One hundred people with suppressed HIV, reporting either PP or no pain, will be assessed two or four times over 6 months. The primary outcomes are distress (Hopkins 25-item symptom checklist), IR (multiplex assay after LPS challenge), and PP (Brief Pain Inventory), assessed at the baseline timepoint, although each will also be assessed at follow-up time points. Induced SH will be assessed in a subsample of 60 participants (baseline timepoint only). To test the hypothesis that IR partly mediates the relationship between distress and pain, mediation analysis will use the baseline data from the PP group to estimate direct and indirect contributions of distress and IR to pain. To test the hypothesis that IR is positively associated with SH, data from the subsample will be analysed with generalised mixed effects models to estimate the association between IR and group membership, with SH as the dependent variable.

ETHICS AND DISSEMINATION

Information obtained from this study will be published in peer-reviewed journals and presented at scientific meetings. The study has been approved by the Human Research Ethics Committee of the University of Cape Town (approval number: 764/2019) and the City of Cape Town (ref: 24699).

TRIAL REGISTRATION NUMBER

NCT04757987.

Comparative Transcriptional Analysis Identified Characteristic Genes and Patterns in HIV-Infected Immunological Non-Responders

Purpose

The incomplete immune reconstitution is a complex phenomenon among human immunodeficiency virus (HIV)-infected patients despite the fact that they have achieved persistent viral suppression under the combined antiretroviral therapy. This study aims to screen and verify the immunological characteristics and underlying mechanisms of immunological non-responders (INRs).

Methods

The RNA-seq and the differentially expressed genes (DEGs) analysis were used to explore potential characteristics among INRs. Gene Ontology (GO) enrichment, ingenuity pathway analysis (IPA) analysis, Gene set enrichment analysis (GSEA) analysis, and the weighted gene co-expression network analysis (WGCNA) were used to explore the potential mechanism. The transcriptional meta-analysis was used to analyze the external efficiency.

Results

The RNA-seq identified 316 DEGs among INRs. The interferon signaling pathway was enriched via GO and IPA analysis among DEGs. The combined GSEA and WGCNA analysis confirmed that the IFN response was more correlated with INR. Furthermore, IFI27 (IFN-α Inducible Protein 27, also known as ISG12) was chosen based on combined DEG analysis, WGCNA analysis, and the transcriptional meta-analysis conducted on other published datasets about INRs. The expression of IFI27 was significantly negatively correlated with the CD4+ T-cell counts of PLWH, and the predictive efficiency of IFI27 level in distinguishing PLWH with poor immune recovery was also with significant power (AUC = 0.848).

Conclusion

The enhanced expression of IFI27 and the IFN response pathway are among the important immunological characteristics of INRs and exhibited promising efficiency as biomarkers for CD4⁺ T-cell recovery.

Induction of thymic atrophy and loss of thymic output by type-I interferons during chronic viral infection

Type-I interferon (IFN-I) signals exert a critical role in disease progression during viral infections. However, the immunomodulatory mechanisms by which IFN-I dictates disease outcomes remain to be fully defined. Here we report that IFN-I signals mediate thymic atrophy in viral infections, with more severe and prolonged loss of thymic output and unique kinetics and subtypes of IFN-α/β expression in chronic infection compared to acute infection. Loss of thymic output was linked to inhibition of early stages of thymopoiesis (DN1-DN2 transition, and DN3 proliferation) and pronounced apoptosis during the late DP stage. Notably, infection-associated thymic defects were largely abrogated upon ablation of IFNαβR and partially mitigated in the absence of CD8 T cells, thus implicating direct as well as indirect effects of IFN-I on thymocytes. These findings provide mechanistic underpinnings for immunotherapeutic strategies targeting IFN-1 signals to manipulate disease outcomes during chronic infections and cancers.

CD4+ T cell depletion does not affect the level of viremia in chronically SHIVSF162P3N-infected Chinese cynomolgus monkeys

Chronically SHIV_SF162P3N-infected cynomolgus monkeys were used to determine the effects of the antibody-mediated acute CD4⁺ T cell depletion on viral load as well as on the immunological factors associated with disease progression. Compared with the control animals, CD4⁺ T cell-depleted animals with SHIV infection showed (i) little alteration in plasma viral load over the period of 22 weeks after the depletion; (ii) increased CD4⁺ T cell proliferation and turnover of macrophages at the early phase of the depletion, but subsequent decline to the basal levels; and (iii) little impact on the expression of the inflammatory cytokines and CC chemokines associated with disease progression. These findings indicate that the antibody-mediated acute CD4⁺ T cell depletion had minimal impact on plasma viral load and disease progression in chronically SHIV_SF162P3N-infected cynomolgus monkeys. Future investigations are necessary to identify the key factor(s) related to the immune activation and macrophage infection during the CD4 deletion in chronic viral infection.

Recreational exercise is associated with lower prevalence of depression and anxiety and better quality of life in German people living with HIV

Sedentarism is a risk factor for depression and anxiety. People living with the human immunodeficiency virus (PLWH) have a higher prevalence of anxiety and depression compared to HIV-negative individuals. This cross-sectional study (n = 450, median age 44 (19-75), 7.3% females) evaluates the prevalence rates and prevalence ratio (PR) of anxiety and/or depression in PLWH associated with recreational exercise. A decreased likelihood of having anxiety (PR=0.57; 0.36-0.91; p = 0.01), depression (PR=0.41; 0.36-0.94; p=0.01), and comorbid anxiety and depression (PR = 0,43; 0.24-0.75; p=0.002) was found in exercising compared to non-exercising PLWH. Recreational exercise is associated with a lower risk for anxiety and/or depression. Further prospective studies are needed to provide insights on the direction of this association.

IFNAR1 signaling in NK cells promotes persistent virus infection

Inhibition of type 1 interferon (IFN-I) signaling promotes the control of persistent virus infection, but the underlying mechanisms remain poorly understood. Here, we report that genetic ablation of Ifnar1 specifically in natural killer (NK) cells led to elevated numbers of T follicular helper cells, germinal center B cells, and plasma cells and improved antiviral T cell function, resulting in hastened virus clearance that was comparable to IFNAR1 neutralizing antibody treatment. Antigen-specific B cells and antiviral antibodies were essential for the accelerated control of LCMV Cl13 infection following IFNAR1 blockade. IFNAR1 signaling in NK cells promoted NK cell function and general killing of antigen-specific CD4 and CD8 T cells. Therefore, inhibition of IFN-I signaling in NK cells enhances CD4 and CD8 T cell responses, promotes humoral immune responses, and thereby facilitates the control of persistent virus infection.

Performance evaluation of Elecsys HIV Duo on cobas e 801 using clinical samples in China

The prevalence and incidence of human immunodeficiency viruses (HIV) infection are rapidly increasing, and novel HIV genotypes are emerging. This study evaluated the sensitivity and specificity of Elecsys HIV Duo assay in population with the epidemic of multiple genotypes of HIV-1 infection. Specificity of the Elecsys HIV Duo assay was determined using 3039 serum samples from patients receiving routine HIV-1 screening tests in China. Sensitivity was assessed with seroconversion panels. Additional 67 positive from newly diagnosed HIV-1 infected samples were also included to test assay performance on various HIV-1 genotypes. The assay performance was compared with that of the Elecsys HIV Combi PT assay. The genotypes of all HIV-1 positive samples were determined with phylogenetic analyses on the 1.1 kb Pro-RT region of pol gene for drug resistance tests. The Elecsys HIV Duo assay had a slightly higher specificity (99.93% vs 99.84%) and equivalent sensitivity to Elecsys HIV Combi PT assay. Seventy-two HIV-1 positive samples, including 12 antigens positive samples, were distinguished by Elecsys HIV Duo. Among them, 43 samples were circulating recombinant form (CRF)01_AE, followed by 13 of CRF07_BC, 10 of subtype B, 4 of URF_0107, 1 of URF_01B and 1 of CRF02_AG. The Elecsys HIV Duo assay showed good performance for the Chinese population with an epidemic of multiple HIV genotypes.

Small RNA sequencing of extracellular vesicles identifies circulating miRNAs related to inflammation and oxidative stress in HIV patients

Background

Extracellular vesicles (EVs) are nano-sized particles secreted by most cells. EVs carry nucleic acids that hold promise as potential biomarkers in various diseases. Human immunodeficiency virus type 1 (HIV) infects CD4+ T cells and induces immune dysfunction, inflammation, and EV secretion, but little is known about EV small RNA cargo in relation to immune dysregulation in HIV-infected individuals. Here, we characterize small RNA carried by circulating EVs in HIV-positive subjects on antiretroviral therapy (ART) relative to uninfected controls by next-generation RNA sequencing.

Results

Plasma EVs isolated from HIV-positive and HIV-negative subjects in test (n = 24) and validation (n = 16) cohorts were characterized by electron microscopy, nanoparticle tracking analysis, and immunoblotting for exosome markers. EVs were more abundant in plasma from HIV-positive compared to HIV-negative subjects. Small RNA sequencing of plasma EVs in the test cohort identified diverse small RNA species including miRNA, piRNA, snRNA, snoRNA, tRNA, and rRNA, with miRNA being the most abundant. A total of 351 different miRNAs were detected in plasma EVs, with the top 50 miRNAs accounting for 90% of all miRNA reads. miR-26a-5p was the most abundant miRNA, followed by miR-21-5p and miR-148-3p. qRT-PCR analysis showed that six miRNAs (miR-10a-5p, − 21-5p, −27b-3p, − 122-5p, −146a-5p, − 423-5p) were significantly increased in plasma EVs from HIV-positive compared to HIV-negative subjects in the validation cohort. Furthermore, miR-21-5p, −27b-3p, −146a-5p, and − 423-5p correlated positively with metabolite markers of oxidative stress and negatively with anti-inflammatory polyunsaturated fatty acids. Over-representation and pathway enrichment analyses of miRNAs and their target genes predicted functional association with oxidative stress responses, interferon gamma signaling, Toll-like receptor signaling, TGF beta signaling, and Notch signaling.

Conclusions

HIV-positive individuals on ART have increased abundance of circulating EVs carrying diverse small RNAs, with miRNAs being the most abundant. Several miRNAs associated with inflammation and oxidative stress are increased in circulating EVs of HIV-positive individuals, representing potential biomarkers of targetable pathways that contribute to disease pathogenesis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12865-020-00386-5.

Antiviral Activity of Fecal Water Samples from HIV-1 Infected Subjects Treated with a Specific Probiotic Formulation

OBJECTIVES

The aim of the study was to investigate if the supplementation with multistrain probiotics may be able to modulate T cell response in HIV-1 infected patients and to evaluate the anti-HIV activity of probiotic by studying fecal water (FW) samples.

METHODS

Three HIV-1-positive patients (Pt1, Pt2 and Pt3) on long-term suppressive combined antiretroviral therapy (cART) received a specific multi-strain probiotic supplementation (Vivomixx ®), for six months (T6). Levels of T cell subsets were evaluated by flow cytometry. Anti- HIV activity of FW samples was evaluated in vitro.

RESULTS

CD4+ T cells levels increased in all HIV-1 infected patients whereas activation markers (CD38 and HLA-DR) were decreased both on CD4+ and CD8+ T cells. FW samples presented an increased inhibitory activity against HIV-1 compared to T0 (FW-Pt1: T0 =40%, T6 = 65% of reduction; FW Pt2: T0 = 26%, T6 = 46% of reduction; FW Pt3: T0 = 47%, T6 = 94% of reduction).

DISCUSSION

Our data suggest that the administration of the specific probiotic formulation improves the antiviral status of people living with HIV-1 under cART, also modulating T cell response.

CONCLUSION

Anti-HIV activity of FW may have several public health and social implications for sexually transmitted diseases that need to be further explored.

Persistent Innate Immune Stimulation Results in IRF3-Mediated but Caspase-Independent Cytostasis

Persistent virus infection continuously produces non-self nucleic acids that activate cell-intrinsic immune responses. However, the antiviral defense evolved as a transient, acute phase response and the effects of persistently ongoing stimulation onto cellular homeostasis are not well understood. To study the consequences of long-term innate immune activation, we expressed the NS5B polymerase of Hepatitis C virus (HCV), which in absence of viral genomes continuously produces immune-stimulatory RNAs. Surprisingly, within 3 weeks, NS5B expression declined and the innate immune response ceased. Proteomics and functional analyses indicated a reduced proliferation of those cells most strongly stimulated, which was independent of interferon signaling but required mitochondrial antiviral signaling protein (MAVS) and interferon regulatory factor 3 (IRF3). Depletion of MAVS or IRF3, or overexpression of the MAVS-inactivating HCV NS3/4A protease not only blocked interferon responses but also restored cell growth in NS5B expressing cells. However, pan-caspase inhibition could not rescue the NS5B-induced cytostasis. Our results underline an active counter selection of cells with prolonged innate immune activation, which likely constitutes a cellular strategy to prevent persistent virus infections.

Parallel studies of mucosal immunity in the reproductive and gastrointestinal mucosa of HIV-infected women

PROBLEM

The effects of HIV on the gastrointestinal tract (GIT), including CD4 depletion, epithelial disruption, and collagen deposition, are well documented and only partially reversed by combination antiretroviral therapy (cART). However, the effects of HIV on the female reproductive tract (FRT) are poorly understood, and most studies have focused on ectocervix and vagina without assessing the upper tract. Here, we investigated CD4⁺ T-cell frequency, phenotype, and HIV-specific T-cell responses in the endocervix and endometrium of HIV-infected women, comparing these tissues to the GIT.

METHOD OF STUDY

Mucosal samples and blood were obtained from 18 women: four who were HIV-positive and not on cART for at least 3 years prior to sampling, including two natural controllers (viral load [VL] undetectable and CD4 >350); nine women on cART with low to undetectable VL; and five HIV-uninfected women. Mucosal samples included terminal ileum, sigmoid colon, endocervical cytobrush, endocervical curettage, and endometrial biopsy. T-cell frequency, phenotypes, and HIV-specific T-cell responses were analyzed by multiparameter flow cytometry.

RESULTS

T-cell activation, measured by CD38/HLA-DR co-expression, remained significantly elevated in endometrium following cART, but was lower in gastrointestinal tissues. HIV-specific CD8⁺ T-cell responses were detected in ileum, colon, and endometrial tissues of women both on and off cART, and were of higher magnitude on those not on cART.

CONCLUSION

Our findings reveal differences in CD4⁺ T-cell frequencies, immune activation, and HIV-specific T-cell responses between the gastrointestinal and reproductive tracts, and highlight differences between HIV controllers and women on cART.

Physical Activity and HIV: Effects on Fitness Status, Metabolism, Inflammation and Immune-Activation

Several studies evidenced that a sedentary lifestyle is related with higher levels of systemic inflammation and highlighted that physical activity can trigger anti-inflammatory effects. To evaluate the impact of self-prescribed physical activity on fitness status, metabolism, inflammation and immune-activation in people living with HIV, an interim analysis of the results of the clinical trial PRIMO (NCT03392805) was performed. Patients enrolled were divided in 2 groups on the basis of self-prescribed physical activity: a physically active group (self-prescribed physical activity) and a sedentary group. Physical fitness was evaluated by sport medicine specialists and related to nutritional status, anthropometric variables, adipokines levels (adiponectin, leptin, resistin), peripheral immune-activation (CD38, HLA-DR on CD4 and CD8), and plasma inflammatory markers (IL-6 and TNF-α). The physically active group had a better profile in anthropometric measures and aerobic fitness but did not show lower levels of immune-activation compared to sedentary group. Also serum IL-6, TNF-α, and adipokines levels showed no statistical differences. On the basis of these data, a regular self-organized physical activity seems useful to improve cardio-respiratory fitness, but unable to control HIV-related immune-activation.

Associations between recent thymic emigrants and CD4+ T-cell recovery after short-term antiretroviral therapy initiation

Supplemental Digital Content is available in the text

Objective:

Around 20–30% of HIV-infected individuals (HIV+) on successful antiretroviral therapy (ART) fail to normalize their CD4⁺ T-cell counts. Various factors could contribute to the lack of immune reconstitution, one of them being thymic insufficiency. We aimed to explore associations between recent thymic emigrants (RTEs) and CD4⁺ T-cell recovery.

Design:

ART-naive HIV+ individuals who started ART with advanced AIDS were selected. Good versus poor immune reconstitution was defined by CD4⁺ gains above or below 100 CD4⁺ T cells/μl. The follow-up period was 6 months.

Methods:

Peripheral blood mononuclear cells were isolated and flow cytometry was used to characterize RTEs as the fraction of naive CD4⁺ T cells expressing CD31⁺, the platelet endothelial cell adhesion molecule. Markers of cellular activation, senescence, exhaustion and cycling were also assessed.

Results:

After 6 months on ART, HIV+ individuals with good immune reconstitution had higher absolute numbers of RTEs, compared with those with poor immune reconstitution, and these strongly correlated with CD4⁺ gains in those individuals with good immune reconstitution but not with poor immune reconstitution. We also found that CD8⁺ T-cell immune activation decreased as early as 2 months post-ART initiation in individuals with good immune reconstitution, but only at month 6 post-ART in individuals with poor immune reconstitution. Levels of immune activation were inversely correlated with the absolute numbers of RTEs in both groups, but more strongly so in individuals with poor immune reconstitution.

Conclusion:

We show that RTEs are linked to CD4⁺ T-cell recovery and that the degree of immune reconstitution is not directly linked to persistent immune activation.

Endothelial Activation, Innate Immune Activation, and Inflammation Are Associated With Postbronchodilator Airflow Limitation and Obstruction Among Adolescents Living With HIV

BACKGROUND

Chronic inflammation, innate immune activation, T-cell imbalance and endothelial activation have been linked with lung diseases. We sought to determine whether markers of these pathophysiologic pathways were associated with spirometry and chest computed tomography (CT) abnormalities among adolescents living with HIV (ALWH).

SETTING

Coptic Hope Center for Infectious Diseases in Nairobi, Kenya.

METHODS

We performed a cross-sectional study of ALWH (10-19 years old). Participants underwent chest CT, spirometry, and venipuncture for serum biomarkers. We also collected demographic, anthropometric, T-cell subset, antiretroviral therapy, and exposure data. We compared characteristics and biomarkers by airflow obstruction [postbronchodilator FEV1/FVC z-score (zFEV1/FVC) < -1.64]. We used multivariable linear regression to determine associations of log10-transformed biomarkers and chest CT abnormalities with lower postbronchodilator zFEV1/FVC (airflow limitation). We performed exploratory principal components analysis on biomarkers, and determined associations of factors with postbronchodilator zFEV1/FVC and chest CT abnormalities.

RESULTS

Of 47 participants with acceptable quality spirometry, 21 (45%) were female, median age was 13 years and 96% had perinatally-acquired HIV. Median CD4 was 672 cells/µL. Overall, 28% had airflow obstruction and 78% had a chest CT abnormality; airflow obstruction was associated with mosaic attenuation (P = 0.001). Higher endothelial activation (sVCAM-1, sICAM-1), inflammation and innate immune activation (serum amyloid-A, sTREM-1, sCD163), and T-cell imbalance (lower CD4/CD8) markers were associated with airflow limitation. Factors comprising endothelial and innate immune activation were associated with airflow limitation.

CONCLUSIONS

Endothelial activation, innate immune activation, T-cell imbalance, and chronic inflammation are associated with airflow limitation and obstruction, providing insights into chronic lung disease pathophysiology among ALWH.

Real word outcomes associated with use of raltegravir in older people living with HIV: results from the 60 months follow-up of the RAL-age cohort

Objective: In people living with HIV (PLWH), antiretroviral treatments have increased the median life expectancy. Raltegravir (RAL) represents a long-term safe regimen used both in the first-line antiretroviral treatments and in the optimization strategies. Aim of the study was to evaluate the real-life efficacy, tolerability, and safety of the long-term RAL use in a multicenter cohort of elderly PLWH.Methods: A 60-month follow-up observational study was carried out in the RAL-AGE Cohort including aged PLWH (≥60 years old) treated with RAL-based regimens (n = 96). The control group was a cohort of PLWH aged less than 60 years (n = 50).Results: RAL treated aged HIV population experiences an increase of CD4⁺ cells and a stable control of viral load at 60 months of follow-up. A significant improvement in lipid metabolism profile, a decrease of platelet count and a reduction in cardiovascular risk levels were observed in the older population. Immune activation markers expressed on CD4⁺ T cells decreased compared to baseline, but this difference was greater in the control group.Conclusion: A 60-month treatment with RAL-containing regimens is safe and highly effective in the older PLWH and these data give new insights on the elderly population.Clinical trial registration: NCT02765776 and NCT03579485.

USP18 is a significant driver of memory CD4 T-cell reduced viability caused by type I IFN signaling during primary HIV-1 infection

The loss of Memory CD4 T-cells (Mem) is a major hallmark of HIV-1 immuno-pathogenesis and occurs early during the first months of primary infection. A lot of effort has been put into understanding the molecular mechanisms behind this loss, yet they still have not been fully identified. In this study, we unveil the unreported role of USP18 in the deleterious effects of sustained type I IFN signaling on Mem, including HIV-1-specific CD4 T-cells. We find that interfering with IFN-I signaling pathway in infected patients, notably by targeting the interferon-stimulated gene USP18, resulted in reduced PTEN expression similar to those observed in uninfected control donors. We show that AKT activation in response to cytokine treatment, T-cell receptor (TcR) triggering, as well as HIV-1 Gag stimulation was significantly improved in infected patients when PTEN or USP18 were inhibited. Finally, our data demonstrate that higher USP18 in Mem from infected patients prevent proper cell survival and long-lasting maintenance in an AKT-dependent manner. Altogether, we establish a direct role for type I IFN/USP18 signaling in the maintenance of total and virus-specific Mem and provide a new mechanism for the reduced survival of these populations during primary HIV-1 infection.

In this study, we expend our knowledge of how type I interferons (IFN-I) leads to memory CD4 T-cell defective survival by unveiling the molecular mechanism behind such impairments, placing USP18 at its center. Our data further deciphers the specific USP18-related mechanism that is responsible for such impairments by implicating AKT inhibition in a PTEN-dependent manner. Our findings also point to a potential use of neutralizing anti-interferon α/β receptor antibodies to rescue the defective memory CD4 T-cell survival during HIV-1 infection, even in HIV-1 specific CD4 T-cell. To conclude, our findings provide the characterization of the molecular pathway leading to disturbances caused by sustained IFN-I signaling which occurs early during primary HIV-1 infection, complementing current knowledge which placed sustained IFN-I signaling as detrimental to the host during this infection.

Challenges in the management of HIV infection: update on the role of probiotic supplementation as a possible complementary therapeutic strategy for cART treated people living with HIV/AIDS

Introduction: Recent insights show that gut-mucosal immunity and intestinal microbiota play a key role in the pathogenesis of HIV infection. Alterations in the composition of intestinal flora (dysbiosis) could be associated with an impaired intestinal epithelium barrier activity and an impaired mucosal immunity function, significantly contributing to microbial translocation which is considered a major driver of chronic immune activation. Areas covered: This article provides an overview on the novel trends in probiotic therapy application. A particular emphasis is addressed to the importance of probiotics as a novel strategy to attenuate or prevent gastrointestinal involvement and to improve gut-mucosal immunity in HIV-infected subjects. Therefore, opportunities, limits and methodological criticalities of supplementation with probiotic therapy are considered and analyzed. Expert opinion: Use of probiotics is emerging as a novel strategy to manage dysbiosis and gut-mucosal impairment, to reduce immune activation and to limit a number of non-AIDS-related disorders. However, despite the growing use of probiotic therapy, mechanisms by which oral bacteria intake exhibits its effects are strain-related and disease-specific, hence clinicians need to take these two factors into consideration when suggesting probiotic supplementation to HIV-infected patients.

Physical activity and quality of life in people living with HIV

As life expectancy in people living with HIV (PWH) has increased, the focus of management has shifted to preventing and treating chronic illnesses. Regular physical activity (PA) has been shown to reduce the impact of HIV on both physical and mental health. Our objectives were to assess the PA levels of PWH compared to HIV negative controls; investigate factors associated with PA; and determine the effect of PA levels on quality of life and mental well-being. We recruited 110 PWH and 110 HIV negative controls in this cross-sectional, single-centre study. Physical activity, quality of life and mental well-being were assessed using the rapid assessment of physical activity tool, EQ-5D-5L Questionnaire, and the Warwick-Edinburgh Mental Well-being Score. Binary logistic regression and multiple linear regression were used to identify factors associated with PA levels and mental well-being scores respectively. PWH were less likely to meet the WHO-recommended PA requirements compared to controls (50.0% vs. 64.5%; p = 0.041) and had significantly lower mental wellbeing and quality of life scores. Additionally, in PWH higher PA levels were associated with improved self-rated quality of life scores (p = 0.027). Our results suggest that targeted exercise programmes could have a beneficial effect on health status in PWH.

TLR9 polymorphism correlates with immune activation, CD4 decline and plasma IP10 levels in HIV patients

Background

The mechanism behind HIV mediated immune activation remains debated, although the role of virus replication in this process is increasingly evident. Toll like Receptor 9 (TLR9) has been implicated in HIV mediated immune activation via sensing of viral CpG DNA. Polymorphisms in the TLR9 gene and promoter region including TLR9 1635A/G and 1486C/T have been found to be associated with multiple infectious diseases and cancers.

Methods

In the current study, we looked at the correlation of TLR9 polymorphisms 1635A/G and 1486C/T with key hallmarks of HIV disease in a cohort of 50 HIV infected patients. We analyzed CD4 counts, T cell immune activation characterized by upregulation of CD38 and HLA-DR and upregulation of plasma biomarkers of inflammation like LPS, sCD14, IL-6 and IP10 in the HIV patient cohort and compared it to healthy controls.

Results

We found that TLR9 1635AA genotype was associated with lower CD4 counts and significantly higher immune activation in both CD4+ and CD8+ T cells. Analysis of HIV associated plasma biomarkers including LPS, sCD14, IL-6 and IP10 revealed a strong correlation between IP10 and immune activation. Interestingly, IP10 levels were also found to be higher in HIV patients with the 1635AA genotype. Furthermore, the TLR9 1486C/T polymorphism that is in linkage disequilibrium with 1635A/G was weakly associated with lower CD4 counts, higher CD8 immune activation and higher IP10 levels.

Conclusions

As TLR9 stimulation is known to induce IP10 production by dendritic cells, our findings provide new insights into HIV mediated immune activation and CD4 loss. TLR9 stimulation by viral CpG DNA may be important to HIV immunopathogenesis and the TLR9 polymorphisms 1635A/G and 1486C/T may be associated with disease progression.

Increased degranulation of immune cells is associated with higher cervical viral load in HIV-infected women

OBJECTIVE

The activation of effector immune cells at the cervicovaginal mucosa (CVM) might influence the cervical HIV load and thus the secondary transmission; however, limited information is available about the innate effector cells at CVM during HIV infection. In this study, we quantified and assessed the activation of the effector immune cells at the CVM of HIV-infected women with different disease outcomes: nonprogressive HIV disease (LTNPs) and chronic HIV-infected (CHI) and their relationship with cervical viral shedding.

METHOD

The phenotype and frequency of cytobrush-derived effector immune cells like natural killer cells, T cells, and dendritic cells and their degranulation status (CD107a expression as a surrogate marker of activation) was determined using flow cytometry in age-matched HIV- infected and uninfected women and their association with cervical HIV load was determined.

RESULT

The frequencies of dendritic cells, CD56, CD56 natural killer cell subsets were similar in both the study groups and also within the HIV-infected women with and without progressive disease. The frequencies of CD56CD16 natural killer cells (P = 0.04) and degranulating CD56 natural killer cells were significantly higher among HIV-infected women (P < 0.05). Among HIV-infected women, LTNP women showed reduced degranulation of natural killer and CD8 T cells than seen in the CHI women, which was also associated with lower cervical viral load (P < 0.05).

CONCLUSION

The present study showed that increased degranulation of natural killer and T cells is associated with higher HIV shedding at the CVM of HIV-infected women. Hence reduction of the local immune activation at CVM could be an effective strategy to reduce the cervical viral load.

Direct-acting antiviral therapy enhances total CD4+ and CD8+ T-cells responses, but does not alter T-cells activation among HCV mono-infected, and HCV/HIV-1 co-infected patients

AIM

Chronic immune activation and poor T-cell immune response are strongly associated with disease progression and pathogenesis of both hepatitis C virus (HCV) and human immunodeficiency virus (HIV)-1 infections. Little is known about the impact of anti-HCV Interferon (IFN)-free direct-acting antiviral (DAA) therapy on the systemic T-cells activation and patterns of peripheral T-cells producing pro-inflammatory cytokines.

PATIENTS AND METHODS

Forty-five subjects including 18 HCV mono-infected, 17 HCV/HIV-1 co-infected patients under antiretroviral therapy (ART), and 10 healthy controls (HCs) were recruited. Blood samples were collected at baseline (T0) and 12 weeks after the end of DAA therapy (T1). Cell phenotypes (CD3, CD4, CD8), activation markers (CD38 and HLA-DR), and frequency of IFN-γ, interleukin (IL)-17, and IL-22 producing CD4+ and CD8+ T-cells were measured by flow cytometry. Plasma levels of related cytokines were also measured by enzyme-linked immunosorbent assay (ELISA).

RESULTS

Both HCV, and HCV/HIV-1 patients before and after therapy, showed significant higher percentages of any T-cell subset expressing CD38 and/or HLA-DR compared to HCs. No differences were observed in T-cells activation at T1 compared to T0 in patient groups, and when HCV patients were compared to HCV/HIV-1 group (P>0.05). After therapy, the potential of total circulating T helper (Th) and T cytotoxic (Tc) cells producing IFN-γ, IL-17, and IL-22 were increased. Plasma level of IFN-γ at baseline was showed difference compared to HCs, and significantly reduced after therapy (P<0.05).

CONCLUSION

Total T-cells immune response enhances after therapy, however, the state of immune activation may remain elevated for a longtime after the end of treatment and contribute to post-Sustained Virologic Response (SVR) consequences.

Type I/II Interferon in HIV-1-Infected Patients: Expression in Gut Mucosa and in Peripheral Blood Mononuclear Cells and Its Modification upon Probiotic Supplementation

Expression of type I and II interferon (IFN) was evaluated in gut-associated lymphoid tissue (GALT) and peripheral blood mononuclear cells (PBMCs) of HIV-1-positive patients on long-term, suppressive, antiretroviral therapy before and after probiotic supplementation. IFNα subtypes and IFNβ were expressed at higher levels in GALT compared to PBMC, whereas an opposite trend of expression was recorded for IFNγ. An increase of IFNα6, IFNα10, IFNα14, IFNα17, and IFNα21 and a decrease of IFNγ were observed in both anatomical sites after probiotic supplementation.

Exosome markers associated with immune activation and oxidative stress in HIV patients on antiretroviral therapy

Exosomes are nanovesicles released from most cell types including immune cells. Prior studies suggest exosomes play a role in HIV pathogenesis, but little is known about exosome cargo in relation to immune responses and oxidative stress. Here, we characterize plasma exosomes in HIV patients and their relationship to immunological and oxidative stress markers. Plasma exosome fractions were isolated from HIV-positive subjects on ART with suppressed viral load and HIV-negative controls. Exosomes were characterized by electron microscopy, nanoparticle tracking, immunoblotting, and LC-MS/MS proteomics. Plasma exosomes were increased in HIV-positive subjects compared to controls, and correlated with increased oxidative stress markers (cystine, oxidized cys-gly) and decreased PUFA (DHA, EPA, DPA). Untargeted proteomics detected markers of exosomes (CD9, CD63, CD81), immune activation (CD14, CRP, HLA-A, HLA-B), oxidative stress (CAT, PRDX1, PRDX2, TXN), and Notch4 in plasma exosomes. Exosomal Notch4 was increased in HIV-positive subjects versus controls and correlated with immune activation markers. Treatment of THP-1 monocytic cells with patient-derived exosomes induced expression of genes related to interferon responses and immune activation. These results suggest that exosomes in ART-treated HIV patients carry proteins related to immune activation and oxidative stress, have immunomodulatory effects on myeloid cells, and may have pro-inflammatory and redox effects during pathogenesis.

Effects of HIV infection and ART on phenotype and function of circulating monocytes, natural killer, and innate lymphoid cells

HIV infection causes upregulation of markers of inflammation, immune activation and apoptosis of host adaptive, and innate immune cells particularly monocytes, natural killer (NK) and innate lymphoid cells (ILCs). Although antiretroviral therapy (ART) restores CD4 T-cell counts, the persistent aberrant activation of monocytes, NK and ILCs observed likely contributes to the incomplete recovery of T-cell effector functions. A better understanding of the effects of HIV infection and ART on the phenotype and function of circulating monocytes, NK, and ILCs is required to guide development of novel therapeutic interventions to optimize immune recovery.

The HIV-1 Tat protein affects human CD4+ T-cell programing and activation, and favors the differentiation of naïve CD4+ T cells

OBJECTIVE

HIV infection is characterized by several immune dysfunctions, such as chronic activation of the immune system, premature aging and loss of CD4 T cells, in particular within the naïve compartment. The Tat protein of HIV is released extracellularly and enters neighboring cells affecting their functionality, for instance impacting on CD8 T-cell programs and activity. As the presence and/or induction of anti-Tat immune responses is associated with reduced T-cell dysfunction and CD4 T-cell loss, we investigated whether Tat impacts human resting or activated CD4 T cells.

METHODS

Purified CD4 T cells were activated by T cell receptor engagement in the presence or absence of Tat. Cytokine production, surface phenotype and expression of transcription factors important for T-cell programing were measured. Purified naïve CD4 T cells were cultured in nonpolarizing conditions in the presence or absence of Tat and their proliferation and differentiation was evaluated.

RESULTS

Tat favors the secretion of IL2, IFNγ and TNFα in CD4 T cells, as well as the upregulation of T-bet and Eomes expression. Naïve CD4 T cells cultured in the presence of Tat showed enhanced expansion and differentiation toward memory phenotype, showing in particular recruitment into the effector memory T-cell pool.

CONCLUSION

Tat affects the programing and functionality of CD4 T lymphocytes favoring the differentiation of naïve CD4 T cells.

Intestinal Barrier Impairment and Immune Activation in HIV-Infected Advanced Late Presenters are Not Dependent on CD4 Recovery

Damage of the mucosal barrier in HIV infection, microbial translocation, and immune activation can persist even in patients on successful antiretroviral therapy (ART) especially advanced late presenters. The aim of this study was to find factors that determine immune activation and bacterial translocation in HIV-infected advanced late presenters on suppressive ART. Forty-three late presenters (CD4 < 200 cells/µl prior to ART) on successful ART (more than 2 years of ART) with optimal and suboptimal CD4 recovery were enrolled into this study. The serum concentrations of intestinal fatty acid-binding peptide (I-FABP), zonulin-1, programmed cell death-1 protein (PCDP-1), and soluble (s)CD14 were measured using the ELISA test. We found higher serum levels of I-FABP and sCD14 in successfully antiretroviral-treated advanced late presenters compared to healthy subjects (p < 0.0001 and p = 0.0004). The serum concentration of PCDP-1 and zonulin-1 in HIV-infected patients did not differ from healthy controls. The levels of microbial translocation and immune activation markers were not associated with the degree of CD4 recovery. A serum concentration of I-FABP above 2.03 ng/ml was independently associated with a shorter ART (OR 0.78; p = 0.03). Older age was related to serum levels of sCD14 above 2.35 µg/ml (OR 1.1; p = 0.01). Higher serum levels of I-FABP and sCD14 in successfully antiretroviral-treated advanced late presenters compared to healthy subjects suggest an incomplete reconstruction of the intestinal barrier and sustained immune activation despite good CD4 recovery. It was not the CD4 level, but the length of the suppressive ART that was found to be associated with the restoration of the intestinal barrier.

Changes in inflammatory/cardiac markers of HIV positive patients

HIV replication promotes atherogenesis and participates in the immune response to the virus, thereby influencing the inflammatory profile. These changes may, in turn, contribute to the risk of cardiovascular diseases with involvement of platelets. However, adenine nucleotides and nucleosides involved in thromboregulation and modulation of immune response may therefore be affected by these alterations.

OBJECTIVES

This study sought to evaluate the profile of pro and anti-inflammatory cytokines (IL-10, IL-6, IL-17, TNF, IL-4, IL-2 and IFN-gamma), cardiac markers (troponin, CK, CK MB, LDH, CRP) in HIV-positive patients and assess the in vitro effect of antiretroviral therapy on the activities of ectonucleotidases (E-NTPDase and E-5'-nucleotidase) in human platelets.

DESIGN AND METHODS

Blood samples were obtained from ten HIV positive patients at the Infectious Disease Clinic of the University Hospital of Santa Maria, Brazil and ten HIV negative individuals (control group) for this study.

RESULTS

The results revealed that there were significant (P < 0.05) increases in serum levels of IL-6 and IFN-gamma with no significant (P > 0.05) changes in the serum levels of the cardiac markers investigated (CK, CK-MB, troponin, LDH and CRP). In addition, the ectonucleotidases (E-NTPDase and E-5'-nucleotidase) activities were not altered (P > 0.05) in human platelets when incubated with different antiretroviral drugs in vitro.

CONCLUSIONS

The results of this study suggest that, despite successful treatment, a proinflammatory state is not altered in HIV patients, and that antiretroviral therapy per se does not change the purinergic profile.

The Significance of Type-I Interferons in the Pathogenesis and Therapy of Human Immunodeficiency Virus 1 Infection

Type-I interferons (IFN-I) are a widely expressed family that could promote antivirus immunity in the process of pathogens invasion. In a human immunodeficiency virus 1 (HIV-1)-infected individual, the production of IFN-I can be detected as early as the acute phase and will persist throughout the course of infection. However, sustained stimulation of immune system by IFN-I also contributes greatly to host-mediated immunopathology and diseases progression. Although the protective effects of IFN-I in the acute phase of HIV-1 infection have been observed, more studies recently focus on their detrimental role in the chronic stage. Inhibition of IFN-I signaling may reverse HIV-1-induced immune hyperactivation and furthermore reduce HIV-1 reservoirs, which suggest this strategy may provide a potential way to enhance the therapeutic effect of antiretroviral therapy. Therefore, we review the role of IFN-I in HIV-1 progression, their effects on different immunocytes, and therapeutic prospects targeting the IFN-I system.

Thalidomide is Associated With Increased T Cell Activation and Inflammation in Antiretroviral-naive HIV-infected Individuals in a Randomised Clinical Trial of Efficacy and Safety

Trial Design

Open-label, randomised, controlled, pilot proof-of-concept clinical trial.

Methods

Participants: Antiretroviral naïve adult males with CD4 count ≥ 350 cells/mm³.

Interventions: Patients were randomised to receive thalidomide 200 mg QD for 3 weeks (Thalidomide group) or not (Control group) and followed for 48 weeks.

Objective: We hypothesized that short-term Thalidomide use would reduce HIV related inflammation and HIV replication among antiretroviral naïve HIV infected individuals.

Outcome: Viral loads, CD4/CD8 counts, ultra-sensitive C-reactive protein (US-CRP), cell activation markers, and plasma lipopolysaccharide (LPS) were analyzed.

Randomisation: Unrestricted randomisation.

Blinding: No blinding was used.

Results

Numbers randomised: Thirty recruited individuals were randomised to Thalidomide (16 patients) or Control (14 patients) groups.

Recruitment: Patients were recruited from April 2011 to January 2013.

Outcome: Viral loads remained stable in both groups. During thalidomide treatment, a decrease in CD4/CD8 ratio (p = 0.04), a decrease in CD4 count (p = 0.04), an increase in cell activation calculated by the percentage of CD38 ⁺/HLA-DR⁺ CD8 cells (p < 0.05) and an increase in US-CRP (p < 0.01) were observed in the Thalidomide group, with all parameters returning to baseline levels after thalidomide interruption. We confirmed that thalidomide increased HIV replication in vitro of 6 of 7 samples from long-term antiretroviral suppressed individuals.

Harms: No class 3/4 adverse events occurred.

Conclusions

Short-term use of thalidomide led to an intense transient increase in T cell activation and inflammation, with a decrease in the CD4⁺ cell count without changes to the CD8⁺ cell count. We confirmed that thalidomide acts in vitro as a latency reversal agent and speculate that the in vivo results obtained were due to an increase in HIV replication.

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Short-term Thalidomide use lead to intense increase in inflammatory markers among HIV+ antiretroviral naïve individuals.

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Thalidomide use lead to a transitory decrease in CD4⁺ T cells and CD4/CD8 ratios.

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In vitro complementary studies revealed that Thalidomide acts as an HIV Latency Reversal Agent.

Thalidomide in general presents a potent anti-inflammatory effect, and is still being used for a number of inflammatory diseases and infection. Therefore, Thalidomide investigated here in a randomised clinical trial aiming to mitigate HIV related inflammation among antiretroviral naïve individuals. Surprisingly, the HIV related inflammation increased during Thalidomide use, and in vitro studies demonstrated that Thalidomide is efficient in interrupting HIV latency, one of the major's obstacles for the cure of HIV chronic infection.

Silymarin suppresses basal and stimulus-induced activation, exhaustion, differentiation, and inflammatory markers in primary human immune cells

Silymarin (SM), and its flavonolignan components, alter cellular metabolism and inhibit inflammatory status in human liver and T cell lines. In this study, we hypothesized that SM suppresses both acute and chronic immune activation (CIA), including in the context of HIV infection. SM treatment suppressed the expression of T cell activation and exhaustion markers on CD4+ and CD8+ T cells from chronically-infected, HIV-positive subjects. SM also showed a trend towards modifying CD4+ T cell memory subsets from HIV+ subjects. In the HIV-negative setting, SM treatment showed trends towards suppressing pro-inflammatory cytokines from non-activated and pathogen-associated molecular pattern (PAMP)-activated primary human monocytes, and non-activated and cytokine- and T cell receptor (TCR)-activated mucosal-associated invariant T (MAIT) cells. The data suggest that SM elicits broad anti-inflammatory and immunoregulatory activity in primary human immune cells. By using novel compounds to alter cellular inflammatory status, it may be possible to regulate inflammation in both non-disease and disease states.

Addition of maraviroc to antiretroviral therapy decreased interferon-γ mRNA in the CD4+ T cells of patients with suboptimal CD4+ T-cell recovery

The CCR5 antagonist, maraviroc (MVC), is associated with an enhanced CD4+ T-cell response independent of virological suppression; however, its mechanism of action has not been elucidated. In this study, we confirmed the effect of MVC on CD4+ T-cell count recovery in immunological non-responders, and compared the conventional combination antiretroviral therapy (cART) with MVC-intensified cART. We also investigated the effect of MVC on interferon-γ (IFN-γ) production in CD4+ T cells in vitro and in vivo, and evaluated the relationship between the mRNA level of IFN-γ and the degree of CD4+ T-cell count recovery. In vitro analysis indicated that MVC significantly decreased mRNA levels of IFN-γ in HIV-Tat stimulated CD4+ T cells from healthy donor peripheral blood mononuclear cells. Of the 18 HIV-infected patients treated with MVC-intensified cART, 12 had a significantly increased CD4+ T-cell count after 24 weeks of additional treatment with MVC. In patients exhibiting a response in CD4+ T-cell counts, mRNA levels of IFN-γ in CD4+ T cells were lower than those in patients showing a non-response at baseline and at week 24, while mRNA levels of IFN-γ decreased in both groups at 24 weeks. In conclusion, MVC decreased the mRNA level of IFN-γ in CD4+ T cells in vitro and in vivo, especially in patients whose CD4+ T-cell count increased significantly. We also found that the lower baseline IFN-γ mRNA level and the larger decreased rate of IFN-γ mRNA in CD4+ T cells were associated with a good response to MVC regarding CD4+ T-cell recovery.

The Selective Serotonin Reuptake Inhibitor Citalopram Decreases Human Immunodeficiency Virus Receptor and Coreceptor Expression in Immune Cells

BACKGROUND

This study investigated whether the selective serotonin reuptake inhibitor (SSRI) citalopram downregulates the expression of the human immunodeficiency virus (HIV) receptor cluster of differentiation 4 (CD4) and coreceptors chemokine receptor type 5 and chemokine-related receptor type 4 (CCR5 and CXCR4) on peripheral blood mononuclear cells (PBMCs) and macrophages ex vivo as a potential mechanism of reducing susceptibility to HIV infection.

METHODS

The sample included 150 participants 18-58 years old (59% women, 65% African American, 61% with depression). Monocyte-depleted PBMCs were treated with phytohemagglutinin for 72 hours and then cultured in the presence of interleukin-2 with vehicle control or the SSRI (10(-6) mol/L) for 2 hours. To generate monocyte-derived macrophages, monocytes were cultured for 7 days, after which either vehicle control or SSRI (10(-6) mol/L) was added for 2 hours. RNA was collected from both cell types, and messenger RNA expression of CD4, CCR5, and CXCR4 was measured by real-time polymerase chain reaction.

RESULTS

In PBMCs, SSRI treatment decreased expression of CD4 (p = .009), CCR5 (p = .008), and CXCR4 (p < .0001). In monocyte-derived macrophages, SSRI treatment decreased expression of CD4 (p < .0001) and CXCR4 (p = .0003), but not CCR5 (p = .71). The suppressive effects of the SSRI on receptor expression did not differ as a function of depression diagnosis or depressive symptom severity.

CONCLUSIONS

Treatment with the SSRI at a physiologic dose decreased CD4, CCR5, and CXCR4 expression on PBMCs and macrophages ex vivo. These findings suggest that SSRI treatment, independent of depression status, downregulates HIV receptor and coreceptor expression and may reduce susceptibility of immune cells to HIV infection and decrease inflammation. If clinical trials confirm the present findings, ultimately there may be a role for using SSRI treatment adjunctively in HIV and acquired immunodeficiency syndrome.

HIV-1 Tat Protein Activates both the MyD88 and TRIF Pathways To Induce Tumor Necrosis Factor Alpha and Interleukin-10 in Human Monocytes

In this study, we show that the HIV-1 Tat protein interacts with rapid kinetics to engage the Toll-like receptor 4 (TLR4) pathway, leading to the production of proinflammatory and anti-inflammatory cytokines. The pretreatment of human monocytes with Tat protein for 10 to 30 min suffices to irreversibly engage the activation of the TLR4 pathway, leading to the production of tumor necrosis factor alpha (TNF-α) and interleukin-10 (IL-10), two cytokines strongly implicated in the chronic activation and dysregulation of the immune system during HIV-1 infection. Therefore, this study analyzed whether the HIV-1 Tat protein is able to activate these two pathways separately or simultaneously. Using three complementary approaches, including mice deficient in the MyD88, TIRAP/MAL, or TRIF adaptor, biochemical analysis, and the use of specific small interfering RNAs (siRNAs), we demonstrated (i) that Tat was able to activate both the MyD88 and TRIF pathways, (ii) the capacity of Tat to induce TIRAP/MAL degradation, (iii) the crucial role of the MyD88 pathway in the production of Tat-induced TNF-α and IL-10, (iv) a reduction but not abrogation of IL-10 and TNF-α by Tat-stimulated macrophages from mice deficient in TIRAP/MAL, and (v) the crucial role of the TRIF pathway in Tat-induced IL-10 production. Further, we showed that downstream of the MyD88 and TRIF pathways, the Tat protein activated the protein kinase C (PKC) βII isoform, the mitogen-activated protein (MAP) kinases p38 and extracellular signal-regulated kinase 1/2 (ERK1/2), and NF-κB in a TLR4-dependent manner. Collectively, our data show that by recruiting the TLR4 pathway with rapid kinetics, the HIV-1 Tat protein leads to the engagement of both the MyD88 and TRIF pathways and to the activation of PKC, MAP kinase, and NF-κB signaling to induce the production of TNF-α and IL-10.

IMPORTANCE

In this study, we demonstrate that by recruiting the TLR4 pathway with rapid kinetics, the HIV-1 Tat protein leads to the engagement of both the MyD88 and TRIF pathways and to the activation of PKC-βII, MAP kinase, and NF-κB signaling to induce the production of TNF-α and IL-10, two cytokines strongly implicated in the chronic activation and dysregulation of the immune system during HIV-1 infection. Thus, it may be interesting to target Tat as a pathogenic factor early after HIV-1 infection. This could be achieved either by vaccination approaches including Tat as an immunogen in potential candidate vaccines or by developing molecules capable of neutralizing the effect of the Tat protein.

Coexpression Network Analysis of Benign and Malignant Phenotypes of SIV-Infected Sooty Mangabey and Rhesus Macaque

To explore the differences between the extreme SIV infection phenotypes, nonprogression (BEN: benign) to AIDS in sooty mangabeys (SMs) and progression to AIDS (MAL: malignant) in rhesus macaques (RMs), we performed an integrated dual positive-negative connectivity (DPNC) analysis of gene coexpression networks (GCN) based on publicly available big data sets in the GEO database of NCBI. The microarray-based gene expression data sets were generated, respectively, from the peripheral blood of SMs and RMs at several time points of SIV infection. Significant differences of GCN changes in DPNC values were observed in SIV-infected SMs and RMs. There are three groups of enriched genes or pathways (EGPs) that are associated with three SIV infection phenotypes (BEN⁺, MAL⁺ and mixed BEN⁺/MAL⁺). The MAL⁺ phenotype in SIV-infected RMs is specifically associated with eight EGPs, including the protein ubiquitin proteasome system, p53, granzyme A, gramzyme B, polo-like kinase, Glucocorticoid receptor, oxidative phosyphorylation and mitochondrial signaling. Mitochondrial (endosymbiotic) dysfunction is solely present in RMs. Specific BEN+ pattern changes in four EGPs are identified in SIV-infected SMs, including the pathways contributing to interferon signaling, BRCA1/DNA damage response, PKR/INF induction and LGALS8. There are three enriched pathways (PRR-activated IRF signaling, RIG1-like receptor and PRR pathway) contributing to the mixed (BEN+/MAL+) phenotypes of SIV infections in RMs and SMs, suggesting that these pathways play a dual role in the host defense against viral infections. Further analysis of Hub genes in these GCNs revealed that the genes LGALS8 and IL-17RA, which positively regulate the barrier function of the gut mucosa and the immune homeostasis with the gut microbiota (exosymbiosis), were significantly differentially expressed in RMs and SMs. Our data suggest that there exists an exo- (dysbiosis of the gut microbiota) and endo- (mitochondrial dysfunction) symbiotic imbalance (EESI) in HIV/SIV infections. Dissecting the mechanisms of the exo-endo symbiotic balance (EESB) that maintains immune homeostasis and the EESI problems in HIV/SIV infections may lead to a better understanding of the pathogenesis of AIDS and the development of novel interventions for the rational control of this disease.

Cytokine and Chemokine Signature in Elite Versus Viremic Controllers Infected with HIV

HIV long-term nonprogressors (LTNPs) maintaining high CD4(+) T-cell counts without antiretroviral therapy (ART) are divided into elite controllers (ECs) with undetectable and viremic controllers (VCs) with low viral loads. Little is known about the long-term changes of T-cell subsets and inflammation patterns in ECs versus VCs. The aim of the study was to explore the long-term evolution of CD4(+) T-cell levels in LTNPs and to analyze cytokine profiles in ECs versus VCs. Nineteen ECs and 15 VCs were enrolled from the natural virus controller cohort (NaViC). T-cell counts were monitored over years, the mean annual change was calculated, and plasma concentrations of 25 cytokines were evaluated using a multiplex bead array. While absolute numbers of T cells did not differ between ECs and VCs over time, we observed a significant decrease of CD4(+) T-cell percentages in VCs, but not in ECs (median [interquartile range]: ECs: 37% [28-41] vs. VCs: 29% [25-34]; p = .02). ECs had lower levels of macrophage inflammatory protein-1β (MIP-1β, p = .003), interferon γ-induced protein-10 (IP-10, p = .03), and monokine induced by interferon-γ (MIG, p = .02). CD4(+) T-cell percentages inversely correlated with MIP 1-β (r = -0.42, p = .017) and IP-10 (r = -0.77, p < .0001). A subtle decline of CD4(+) T-cell percentages could be observed in VCs, but not in ECs, which was associated with higher plasma levels of proinflammatory cytokines. Hence, even low levels of HIV replication might go along with a progressive decline in CD4(+) T-cell counts in LTNPs.

What happens to cardiovascular system behind the undetectable level of HIV viremia?

Despite the combined antiretroviral therapy has improved the length and quality of life of HIV infected patients, the survival of these patients is always decreased compared with the general population. This is the consequence of non-infectious illnesses including cardio vascular diseases. In fact large studies have indicated an increased risk of coronary atherosclerotic disease, myocardial infarction even in HIV patients on cART. In HIV infected patients several factors may contribute to the pathogenesis of cardiovascular problems: life-style, metabolic parameters, genetic predisposition, viral factors, immune activation, chronic inflammation and side effects of antiretroviral therapy. The same factors may also contribute to complicate the clinical management of these patients. Therefore, treatment of these non-infectious illnesses in HIV infected population is an emerging challenge for physicians. The purpose of this review is to focus on the new insights in non AIDS-related cardiovascular diseases in patients with suppressed HIV viremia.

Gold(I) complex of 1,1'-bis(diphenylphosphino) ferrocene-quinoline conjugate: a virostatic agent against HIV-1

HIV infection is known for replicating in proliferating CD(+) T-cells. Treatment of these cells with cytostatic (anti-proliferation) compounds such as hydroxyurea interferes with the cells's ability support HIV replication. Combinations of such cytostatic compounds with proven anti-retroviral drugs (like ddI) are known as virostatic, and have been shown to aid in the control of the infection. The use of two different drugs in virostatic combinations however, carries the risk of adverse effects including drug-drug interactions, which could lead to augmented toxicities and reduced efficacy. Here, a novel digold(I) complex of ferrocene-quinoline (3) was investigated for cytostatic behaviour as well as anti-viral activity which if demonstrated would eliminate concerns of drug-drug interactions. The complex was synthesized and characterized by NMR, FT-IR and mass spectroscopy and the molecular structure was confirmed by X-ray crystallography. Bio-screening involved viability dyes, real time electronic sensing and whole virus assays. The complex showed significant (p = 0.0092) inhibition of virus infectivity (83 %) at 10 ug/mL. This same concentration caused cytostatic behaviour in TZM-bl cells with significant (p < 0.01) S and G2/M phase cell cycle arrest. These data supports 3 as a virostatic agent, possessing both anti-viral and cytostatic characteristics. In the absence of 3, TZM-bl cells were infected by a pseudovirus and this was demonstrated through luminescence in a luciferase assay. Pre-incubation of the virus with 3 decreased luminescence, indicating the anti-viral activity of 3. Complex 3 also showed cytostatic behavior with increased S-phase and G2/M phase cell cycle arrest.

Systemic Immune Activation Profiles of HIV-1 Subtype C-Infected Children and Their Mothers

Little is known about immune activation profiles of children infected with HIV-1 subtype C. The current study compared levels of selected circulating biomarkers of immune activation in HIV-1 subtype C-infected untreated mothers and their children with those of healthy controls. Multiplex bead array, ELISA, and immunonephelometric procedures were used to measure soluble CD14 (sCD14), beta-2 microglobulin (β2M), CRP, MIG, IP-10, and transforming growth factor beta 1 (TGF-β1). Levels of all 6 biomarkers were significantly elevated in the HIV-infected mothers and, with the exception of MIG, in their children (P < 0.01–P < 0.0001). The effects of antiretroviral therapy (ART) and maternal smoking on these biomarkers were also assessed. With the exception of TGF-β1, which was unchanged in the children 12 months after therapy, initiation of ART was accompanied by decreases in the other biomarkers. Regression analysis revealed that although most biomarkers were apparently unaffected by smoking, exposure of children to maternal smoking was associated with a significant increase in IP-10. These findings demonstrate that biomarkers of immune activation are elevated in HIV-infected children pre-ART and decline, with the exception of TGF-β1, after therapy. Although preliminary, elevation of IP-10 in smoke-exposed infants is consistent with a higher level of immune activation in this group.

HIV Replication at Low Copy Number and its Correlation with the HIV Reservoir: A Clinical Perspective

The efficacy of combination therapy (antiretroviral therapy - ARV) is demonstrated by the high rates of viral suppression achieved in most treated HIV patients. Whereas contemporary treatments may continuously suppress HIV replication, they do not eliminate the latent reservoir, which can reactivate HIV infection if ARV is discontinued. The persistence of HIV proviral DNA and infectious viruses in CD4+ T cells and others cells has long been considered a major obstacle in eradicating the HIV virus in treated patients. Moreover, recent studies have demonstrated the persistence of HIV replication at low copies in most patients on suppressive ARV. The source of this ‘residual viraemia’ and whether it declines over years of therapy remain unknown. Similarly, little is known regarding the biological relationships between the HIV reservoir and viral replication at low copies. The question of whether this ‘residual viraemia’ represents active replication or the release of non-productive virus from the reservoir has not been adequately resolved.

From a clinical perspective, both the quantification of the HIV reservoir and the detection of low levels of replication in full-responder patients on prolonged ARV may provide important information regarding the effectiveness of treatment and the eradication of HIV. To date, the monitoring of these two parameters has been conducted only for research purposes; the routine use of standardised tests procedure is lacking. This review aims to assess the current data regarding the correlation between HIV replication at low copies and the HIV reservoir and to provide useful information for clinicians.

Type I interferons in viral control and immune regulation

Type 1 interferons (IFN-I) exert pleiotropic biological effects during viral infections, all which contribute to balancing virus control and immune pathology. Despite extensive antiviral functions that subdue virus replication, recent studies demonstrate pathogenic and pro-viral roles for IFN-I signaling during acute and persistent virus infection. IFN-I signaling can promote morbidity and mortality through induction of aberrant inflammatory responses during acute viral infection. In contrast, IFN-I signaling during persistent viral infection supports immune suppression, lymphoid tissue disorganization and CD4 T cell dysfunction. Systematic characterization of the cellular populations and intricacies of IFN-I signaling that promote pathology or immune suppression during acute and persistent viral infections, respectively, should inform the development of treatments and modalities to control viral associated pathologies.

HIV-1 Env Glycoprotein Phenotype along with Immune Activation Determines CD4 T Cell Loss in HIV Patients

The mechanism behind the selective depletion of CD4(+) cells in HIV infections remains undetermined. Although HIV selectively infects CD4(+) cells, the relatively few infected cells in vivo cannot account for the extent of CD4(+) T cell depletion, suggesting indirect or bystander mechanisms. The role of virus replication, Env glycoprotein phenotype, and immune activation (IA) in this bystander phenomenon remains controversial. Using samples derived from HIV-infected patients, we demonstrate that, although IA in both CD4(+) and CD8(+) subsets correlates with CD4 decline, apoptosis in CD4(+) and not CD8(+) cells is associated with disease progression. Because HIV-1 Env glycoprotein has been implicated in bystander apoptosis, we cloned full-length Envs from plasma of viremic patients and tested their apoptosis-inducing potential (AIP). Interestingly, AIP of HIV-1 Env glycoproteins were found to correlate inversely with CD4:CD8 ratios, suggesting a role of Env phenotype in disease progression. In vitro mitogenic stimulation of PBMCs resulted in upregulation of IA markers but failed to alter the CD4:CD8 ratio. However, coculture of normal PBMCs with Env-expressing cells resulted in selective CD4 loss that was significantly enhanced by IA. Our study demonstrates that AIP of HIV-1 Env and IA collectively determine CD4 loss in HIV infection.

Pleiotropic Roles of Type 1 Interferons in Antiviral Immune Responses

Since Isaac's and Lindenmann's seminal experiments over 50 years ago demonstrating a soluble factor generated from heat killed virus-stimulated chicken embryos could inhibit live influenza virus replication, the term interferon has been synonymous with inhibition of virus replication. While the antiviral properties of type 1 interferon (IFN-I) are undeniable, recent studies have reported expanding and somewhat unexpected roles of IFN-I signaling during both acute and persistent viral infections. IFN-I signaling can promote morbidity and mortality through induction of aberrant inflammatory responses and recruitment of inflammatory innate immune cell populations during acute respiratory viral infections. During persistent viral infection, IFN-I signaling promotes containment of early viral replication/dissemination, however, also initiates and maintains immune suppression, lymphoid tissue disorganization, and CD4 T cell dysfunction through modulation of multiple immune cell populations. Finally, new data are emerging illuminating how specific IFN-I species regulate immune pathology and suppression during acute and persistent viral infections, respectively. Systematic characterization of the cellular populations that produce IFN-I, how the timing of IFN-I induction and intricacies of subtype specific IFN-I signaling promote pathology or immune suppression during acute and persistent viral infections should inform the development of treatments and modalities to control viral associated pathologies.

Plasma Levels of Neopterin and C-Reactive Protein (CRP) in Tuberculosis (TB) with and without HIV Coinfection in Relation to CD4 Cell Count

Background

While the risk of TB is elevated in HIV-positive subjects with low CD4 cell counts, TB may in itself be associated with CD4 lymphocytopenia. We investigated markers of immune activation (neopterin) and inflammation (CRP) in TB patients with and without HIV coinfection and their association with CD4 cell levels, and determined their predictive capacity as alternative markers of advanced immunosuppression.

Methods

Participants selected from a cohort of adults with TB at Ethiopian health centers (195 HIV+/TB+, 170 HIV-/TB+) and 31 controls were tested for plasma levels of neopterin and CRP. Baseline levels of neopterin and CRP were correlated to CD4 cell count before and after anti-TB treatment (ATT). The performance to predict CD4 cell strata for both markers were investigated using receiver operating curves.

Results

Levels of both biomarkers were elevated in TB patients (neopterin: HIV+/TB+ 54 nmol/l, HIV-/TB+ 23 nmol/l, controls 3.8 nmol/l; CRP: HIV+/TB+ 36 μg/ml, HIV-/TB+ 33 μg/ml, controls 0.5 μg/ml). Neopterin levels were inversely correlated (-0.53, p<0.001) to CD4 cell count, whereas this correlation was weaker for CRP (-0.25, p<0.001). Neither of the markers had adequate predictive value for identification of subjects with CD4 cell count <100 cells/mm³ (area under the curve [AUC] 0.64 for neopterin, AUC 0.59 for CRP).

Conclusion

Neopterin levels were high in adults with TB, both with and without HIV coinfection, with inverse correlation to CD4 cell count. This suggests that immune activation may be involved in TB-related CD4 lymphocytopenia. However, neither neopterin nor CRP showed promise as alternative tests for immunosuppression in patients coinfected with HIV and TB.

Natural Products as Tools for Defining How Cellular Metabolism Influences Cellular Immune and Inflammatory Function during Chronic Infection

Chronic viral infections like those caused by hepatitis C virus (HCV) and human immunodeficiency virus (HIV) cause disease that establishes an ongoing state of chronic inflammation. While there have been tremendous improvements towards curing HCV with directly acting antiviral agents (DAA) and keeping HIV viral loads below detection with antiretroviral therapy (ART), there is still a need to control inflammation in these diseases. Recent studies indicate that many natural products like curcumin, resveratrol and silymarin alter cellular metabolism and signal transduction pathways via enzymes such as adenosine monophosphate kinase (AMPK) and mechanistic target of rapamycin (mTOR), and these pathways directly influence cellular inflammatory status (such as NF-κB) and immune function. Natural products represent a vast toolkit to dissect and define how cellular metabolism controls cellular immune and inflammatory function.