Reconstitution of intestinal CD4 and Th17 T cells in antiretroviral therapy suppressed HIV-infected subjects: implication for residual immune activation from the results of a clinical trial

Functional and structural neuroretinal disorders in HIV Controllers. Prospective cohort study

OBJECTIVE

To estimate the prevalence and cumulative incidence of neuro-retinal-disorders (NRD) in HIV-controllers.

DESIGN

Prospective, single-centre, cohort study of people living with HIV (PLWH): elite-controllers, long-term-non-progressors and early diagnosed.

METHODS

The study compared "HIV-controllers" (including elite-controllers and long-term-non-progressors), who were not on antiretroviral therapy (ART), and "HIV-treatment" (HIV-infected subjects with a recent diagnosis and on ART). A matched cohort of "non-HIV subjects" was created. NRD was defined as at least one altered (not normal) ophthalmological parameter (functional or structural). Functional (visual acuity, contrast sensitivity, chromatic vision, visual field) and structural parameters (ganglion cells, macular nerve fibre layer, peripapillary nerve fibre layers, vascular calibre) as well as quality of life (Medical Outcomes Study-HIV Short Form-30) were assessed.

RESULTS

Between March 2012 and November 2015, the study included all HIV-controllers (16 elite-controllers, 1 long-term-non-progressor), 11 HIV-treatment and 16 non-HIV. Prevalence of NRD at baseline was 88.2% (15/17, 95% CI: 65.7%-96.7%), 90.9% (10/11, 95% CI: 62.3%-98.4%) and 56.3% (9/16, 95% CI: 33.2%-76.9%), respectively. Cumulative incidence at 3 years was 50% (1/2), 100% (1/1) and 33.3% (2/6), respectively. None of the participants manifested ocular clinical symptoms. Three years later, prevalence of NRD was 92.3% (12/13, 95% CI: 66.7%-98.6%), 75% (6/8, 95% CI: 40.9%-92.9%) and 50.0% (7/14, 95% CI: 26.8%-73.2%), respectively. Contrast sensitivity and structural parameters were globally the most affected among PLWH. Quality of life (total score) [median (interquartile range)] at baseline and 3 years was 82 (71-89) and 74 (63.5-79.25) in HIV-controllers and 80 (73-88) and 88 (83-92) in HIV-treatment.

CONCLUSIONS

HIV-controllers and those individuals on ART presented a higher percentage of NRD than non-HIV. Our results suggest that NRD could be a biomarker of ocular aging among PLWH.

Advances in Mechanism of HIV-1 Immune Reconstitution Failure: Understanding Lymphocyte Subpopulations and Interventions for Immunological Nonresponders

In individuals diagnosed with AIDS, the primary method of sustained suppression of HIV-1 replication is antiretroviral therapy, which systematically increases CD4+ T cell levels and restores immune function. However, there is still a subset of 10-40% of people living with HIV who not only fail to reach normal CD4+ T cell counts but also experience severe immune dysfunction. These individuals are referred to as immunological nonresponders (INRs). INRs have a higher susceptibility to opportunistic infections and non-AIDS-related illnesses, resulting in increased morbidity and mortality rates. Therefore, it is crucial to gain new insights into the primary mechanisms of immune reconstitution failure to enable early and effective treatment for individuals at risk. This review provides an overview of the dynamics of key lymphocyte subpopulations, the main molecular mechanisms of INRs, clinical diagnosis, and intervention strategies during immune reconstitution failure, primarily from a multiomics perspective.

Identification of CD8+ T cell subsets that normalize in early-treated people living with HIV receiving antiretroviral therapy

Background

Although combined antiretroviral therapy (cART) has decreased the mortality associated with HIV infection, complete immune reconstitution is not achieved despite viral suppression. Alterations of CD8⁺ T cells and some of their subpopulations, such as interleukin (IL)-17-producing cells, are evidenced in treated individuals and are associated with systemic inflammation and adverse disease outcomes. We sought to evaluate if different CD8⁺ T cell subsets are differentially normalized during a clinical follow-up of people living with HIV (PLWH) receiving suppressive cART.

Methods

We explored the changes in the frequencies, activation/exhaustion phenotypes (HLA-DR, CD38, PD-1, and TIM-3), and function (total and HIV-specific cells expressing CD107a, perforin, granzyme B, interferon [IFN]-γ and IL-17) of CD8⁺ T cells from early-treated PLWH receiving cART in a 1-year follow-up, using a multidimensional flow cytometry approach.

Results

Despite continuous cART-induced viral suppression and recovery of CD4⁺ T cells, after a 1-year follow-up, the CD8⁺ T cell counts, CD4:CD8 ratio, PD-1 expression, and IL-17 production by CD8⁺ T cells exhibited incomplete normalization compared with seronegative controls. However, the proportion of CD8⁺ T cells with an exhausted phenotype (co-expressing PD-1 andTIM-3), and cells co-expressing cytotoxic molecules (Perforin and Granzyme B), reached normalization.

Conclusions

Although suppressive cART achieves normalization of CD4⁺ T cell counts, only particular subsets of CD8⁺ T cells are more rapidly normalized in PLWH receiving cART, which could be routinely used as biomarkers for therapy efficiency in these patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12981-022-00465-0.

Antiretroviral Therapy Dampens Mucosal CD4+ T Lamina Propria Lymphocytes Immune Activation in Long-Term Treated People Living with HIV-1

HIV infection is characterized by a severe deterioration of an immune cell-mediated response due to a progressive loss of CD4⁺ T cells from gastrointestinal tract, with a preferential loss of IL-17 producing Th cells (Th17), a specific CD4⁺ T cells subset specialized in maintaining mucosal integrity and antimicrobial inflammatory responses. To address the effectiveness of antiretroviral therapy (ART) in reducing chronic immunological dysfunction and immune activation of intestinal mucosa, we conducted a cross-sectional observational study comparing total IFN-γ-expressing (Th1) and IL-17-expressing (Th17) frequencies of CD4⁺ T lamina propria lymphocytes (LPLs) and their immune activation status between 11 male ART-naïve and 11 male long-term ART-treated people living with HIV-1 (PLWH) who underwent colonoscopy and retrograde ileoscopy for biopsies collection. Flow cytometry for surface and intracellular staining was performed. Long-term ART-treated PLWH showed lower levels of CD38⁺ and/or HLA-DR⁺ LPLs compared to ART-naïve PLWH. Frequencies of Th1 and Th17 LPLs did not differ between the two groups. Despite ART failing to restore the Th1 and Th17 levels within the gut mucosa, it is effective in increasing overall CD4⁺ T LPLs frequencies and reducing mucosal immune activation.

Preservation of Gastrointestinal Mucosal Barrier Function and Microbiome in Patients With Controlled HIV Infection

Background

Despite successful ART in people living with HIV infection (PLHIV) they experience increased morbidity and mortality compared with HIV-negative controls. A dominant paradigm is that gut-associated lymphatic tissue (GALT) destruction at the time of primary HIV infection leads to loss of gut integrity, pathological microbial translocation across the compromised gastrointestinal barrier and, consequently, systemic inflammation. We aimed to identify and measure specific changes in the gastrointestinal barrier that might allow bacterial translocation, and their persistence despite initiation of antiretroviral therapy (ART).

Method

We conducted a cross-sectional study of the gastrointestinal (GIT) barrier in PLHIV and HIV-uninfected controls (HUC). The GIT barrier was assessed as follows: in vivo mucosal imaging using confocal endomicroscopy (CEM); the immunophenotype of GIT and circulating lymphocytes; the gut microbiome; and plasma inflammation markers Tumour Necrosis Factor-α (TNF-α) and Interleukin-6 (IL-6); and the microbial translocation marker sCD14.

Results

A cohort of PLHIV who initiated ART early, during primary HIV infection (PHI), n=5), and late (chronic HIV infection (CHI), n=7) infection were evaluated for the differential effects of the stage of ART initiation on the GIT barrier compared with HUC (n=6). We observed a significant decrease in the CD4 T-cell count of CHI patients in the left colon (p=0.03) and a trend to a decrease in the terminal ileum (p=0.13). We did not find evidence of increased epithelial permeability by CEM. No significant differences were found in microbial translocation or inflammatory markers in plasma. In gut biopsies, CD8 T-cells, including resident intraepithelial CD103+ cells, did not show any significant elevation of activation in PLHIV, compared to HUC. The majority of residual circulating activated CD38+HLA-DR+ CD8 T-cells did not exhibit gut-homing integrins α4ß7, suggesting that they did not originate in GALT. A significant reduction in the evenness of species distribution in the microbiome of CHI subjects (p=0.016) was observed, with significantly higher relative abundance of the genus Spirochaeta in PHI subjects (p=0.042).

Conclusion

These data suggest that substantial, non-specific increases in epithelial permeability may not be the most important mechanism of HIV-associated immune activation in well-controlled HIV-positive patients on antiretroviral therapy. Changes in gut microbiota warrant further study.

IL-21 and IFNα therapy rescues terminally differentiated NK cells and limits SIV reservoir in ART-treated macaques

Unlike HIV infection, which progresses to AIDS absent suppressive anti-retroviral therapy, nonpathogenic infections in natural hosts, such African green monkeys, are characterized by a lack of gut microbial translocation and robust secondary lymphoid natural killer cell responses resulting in an absence of chronic inflammation and limited SIV dissemination in lymph node B-cell follicles. Here we report, using the pathogenic model of antiretroviral therapy-treated, SIV-infected rhesus macaques that sequential interleukin-21 and interferon alpha therapy generate terminally differentiated blood natural killer cells (NKG2a/clowCD16+) with potent human leukocyte antigen-E-restricted activity in response to SIV envelope peptides. This is in contrast to control macaques, where less differentiated, interferon gamma-producing natural killer cells predominate. The frequency and activity of terminally differentiated NKG2a/clowCD16+ natural killer cells correlates with a reduction of replication-competent SIV in lymph node during antiretroviral therapy and time to viral rebound following analytical treatment interruption. These data demonstrate that African green monkey-like natural killer cell differentiation profiles can be rescued in rhesus macaques to promote viral clearance in tissues.

High microbial translocation limits gut immune recovery during short-term HAART in the area with high prevalence of foodborne infection

BACKGROUND

Individuals residing in areas with high prevalence of foodborne infection could have a higher risk of gut microbial translocation which may affect monocyte activation, gut immune recovery and intestinal epithelial cell damage. We aimed to measure alterations in microbial translocation, monocyte activation, gut immune recovery, and intestinal epithelial cell damage in HAART treated individuals.

METHODS

A prospective, single-arm, longitudinal, cohort study was conducted among antiretroviral naïve HIV-1 infected Thai participants. All participants were in chronic stage of HIV-1 infection before starting HAART. Data and samples were collected prior to initiation of HAART and then after 24 and 48 weeks of HAART. Plasma biomarkers for microbial translocation (16S rDNA and LBP), monocyte activation (sCD14) and intestinal epithelial cell damage (I-FABP) were evaluated. We measured circulating gut-homing CD4⁺ T cells and circulating gut-homing Th17 cells to assess recoveries of gut immunity and gut immunity to microbial pathogens.

RESULTS

The kinetic studies showed no reduction in the levels of plasma 16S rDNA, sCD14 or I-FABP, significant decrease of plasma LBP level, and slow but significant increases in the frequencies of circulating gut-homing CD4⁺ T cells and circulating gut-homing Th17 cells during 48 weeks of HAART. Dividing participants into low and high microbial translocation (low and high MT) groups at baseline, both groups showed persistent plasma levels of 16S rDNA, sCD14 and I-FABP, and significantly decreased plasma level of LBP. The low MT group had significantly increased frequencies of circulating gut-homing CD4⁺ T cells and circulating gut-homing Th17 cells during 48 weeks of HAART but this was not observed in the high MT group.

CONCLUSIONS

We demonstrated persistent high microbial translocation, monocyte activation and intestinal epithelial cell damage with slow gut immune recovery during successful short-term HAART. Additionally, gut immune recovery was apparently limited by high microbial translocation. Our findings emphasize the adverse impact of high microbial translocation on gut immune recovery and the necessity of establishing a novel therapeutic intervention to inhibit microbial translocation.

Modulation of Phenylalanine and Tyrosine Metabolism in HIV-1 Infected Patients with Neurocognitive Impairment: Results from a Clinical Trial

To investigate the effects of oral bacteriotherapy on intestinal phenylalanine and tyrosine metabolism, in this longitudinal, double-arm trial, 15 virally suppressed HIV+ individuals underwent blood and fecal sample collection at baseline and after 6 months of oral bacteriotherapy. A baseline fecal sample was collected from 15 healthy individuals and served as control group for the baseline levels of fecal phenylalanine and tyrosine. CD4 and CD8 immune activation (CD38⁺) was evaluated by flow cytometry. Amino acid evaluation on fecal samples was conducted by Proton Nuclear Magnetic Resonance. Results showed that HIV+ participants displayed higher baseline phenylalanine/tyrosine ratio values than healthy volunteers. A significand reduction in phenylalanine/tyrosine ratio and peripheral CD4⁺ CD38⁺ activation was observed at the end of oral bacteriotherapy. In conclusion, probiotics beneficially affect the immune activation of HIV+ individuals. Therefore, the restoration of intestinal amino acid metabolism could represent the mechanisms through which probiotics exert these desirable effects.

Cognitive impairment and CSF proteome modification after oral bacteriotherapy in HIV patients

OBJECTIVE

To investigate whether a probiotic supplementation to cART patients modifies the cerebrospinal fluid (CSF) proteome and improves neurocognitive impairment.

METHODS

26 CSF samples from 13 HIV-positive patients [six patients living with HIV (PLHIV) and seven patients with a history of AIDS (PHAIDS)] were analyzed. All patients underwent to neurocognitive evaluation and blood sampling at baseline and after 6 months of oral bacteriotherapy. Immune phenotyping and activation markers (CD38 and HLA-DR) were evaluated on peripheral blood mononuclear cells (PBMC). Plasma levels of IL-6, sCD14, and MIP-1β were detected, by enzyme-linked immunosorbent assay (ELISA). Functional proteomic analysis of CSF sample was conducted by two-dimensional electrophoresis; a multivariate analysis was performed by principal component analysis (PCA) and data were enriched by STRING software.

RESULTS

Oral bacteriotherapy leads to an improvement on several cognitive test and neurocognitive performance in both groups of HIV-positive subjects. A reduction in the percentage of CD4⁺CD38⁺HLA-DR⁺ T cells was also observed at peripheral level after the probiotic intake (p = 0.008). In addition, the probiotic supplementation to cART significantly modifies protein species composition and abundance at the CSF level, especially those related to inflammation (β2-microglobulin p = 0.03; haptoglobin p = 0.06; albumin p = 0.003; hemoglobin p = 0.003; immunoglobulin heavy chains constant region p = 0.02, transthyretin p = 0.02) in PLHIV and PHAIDS.

CONCLUSIONS

Our results suggest that oral bacteriotherapy as a supplement to cART could exert a role in the amelioration of inflammation state at peripheral and CNS level.

Increased IL-17 and/or IFN-γ producing T-cell subsets in gut mucosa of long-term-treated HIV-1-infected women

OBJECTIVE

The influence of sex on gut mucosal T-cell response in HIV-1 infection remains largely unknown. We explored whether the frequencies of interferon-γ and/or IL-17 producing naive, T central memory and T effector memory (TEM) CD4+ (Th1, Th17) and CD8+ T (Tc1, Tc17) cells measured in gut and peripheral districts differed between female and male HIV-1-infected patients.

METHODS

Thirty long-term-treated HIV-1-infected individuals were enrolled. The frequencies of Th1, Th17, Tc1, Tc17-cell subsets (single and double) were evaluated by multiparametric flow cytometry in lamina propria lymphocytes and peripheral blood mononuclear cells (PBMC).

RESULTS

A sex-based pattern was recorded in the differences of Th1, Th17, Tc1, Tc17-cell subset (single and double) frequencies between gut and peripheral blood. Female patients had stronger alterations in the gut mucosal T-cell repertoire, especially increased Th1, Th17, and Th1/Th17-cell subset frequencies, compared with the blood district than their male counterparts. Higher naive Tc1, Tc17, Tc1/Tc17, TEM Tc17, and TEM Tc1/Tc17 levels were also recorded in the gut mucosa than in the PBMC of HIV-1-infected women. Males and females also differed in their gut T-cell response, with women being characterized by higher Th1, Th17, Tc1, Tc17, and Th1/Th17 cells subset levels than men. By contrast, only TEM Th1/Th17 and TEM Tc17 in PBMC differed between males and females.

CONCLUSION

Sex-based differences observed in the gut T-cell response of HIV-1-infected patients might contribute to the disease dimorphism.

Fisetin and telmisartan each alone or in low-dose combination alleviate OVA-induced food allergy in mice

BACKGROUND

Food allergy (FA) is a worldwide health problem, affecting nearly 10% of all populations, with no prophylactic options or regulatory treatment available until now. Fisetin, a biologically active flavonoid, and telmisartan, the highly selective competitive AT1 receptor antagonist, recently exhibited potent anti-inflammatory and immunomodulatory activities. In the present study, we have evaluated the possible anti-inflammatory and immunomodulatory activities of fisetin and telmisartan each alone or in low-dose combination in a mouse model of FA.

METHODS

For induction of FA, eight-week-old BALB/c mice, sensitized by two ip injection of 50 μg ovalbumin (OVA) and 1 mg alum at day 0 and 7. Then, each mouse challenged with 10 mg OVA at days 14, 16, 18, and 21. On the 28^th day, the fifth challenge carried out by oral administration of 50 mg OVA. Either fisetin (1 or 3 mg/kg/d), telmisartan (1 or 3 mg/kg/d) or a combination of fisetin 1 mg/kg/d and telmisartan 1 mg/kg/d received orally from the 13^th day till 28^th day. In challenge days, the treatments received one-hour before the challenge.

RESULTS

Our data showed that fisetin and telmisartan each alone or in low-dose combination attenuated the anaphylactic manifestation, decreased blood eosinophilic count, serum OVA-specific IgE, and IL-4 levels, the intestinal total and degranulated mast cells count, and CD4⁺ immunohistochemical expression. Furthermore, they enhanced the serum IFN-γ level and abrogated the intestinal histopathological changes induced by OVA in mice.

CONCLUSION

Either fisetin, telmisartan or their low-dose combination could be promising in the management of FA.

Combination anti-PD-1 and antiretroviral therapy provides therapeutic benefit against SIV

Therapeutic strategies that augment antiviral immunity and reduce the viral reservoir are critical to achieving durable remission of HIV. The coinhibitory receptor programmed death-1 (PD-1) regulates CD8+ T cell dysfunction during chronic HIV and SIV infections. We previously demonstrated that in vivo blockade of PD-1 during chronic SIV infection improves the function of antiviral CD8+ T cells and B cells. Here, we tested the immunological and virological effects of PD-1 blockade combined with antiretroviral therapy (ART) in rhesus macaques. Administration of anti-PD-1 antibody 10 days prior to ART initiation rapidly enhanced antiviral CD8+ T cell function and diminished IFN-stimulated genes. This resulted in faster viral suppression in plasma and better Th17 cell reconstitution in the rectal mucosa following ART initiation. PD-1 blockade during ART resulted in lower levels of cell-associated replication-competent virus. Following ART interruption, PD-1 antibody-treated animals showed markedly higher expansion of proliferating CXCR5+perforin+granzyme B+ effector CD8+ T cells and lower regulatory T cells that resulted in better control of viremia. Our results show that PD-1 blockade can be administered safely with ART to augment antiviral CD8+ T cell function and reduce the viral reservoir, leading to improved control of viral rebound after ART interruption.

The prevention of 2,4-dinitrochlorobenzene-induced inflammation in atopic dermatitis-like skin lesions in BALB/c mice by Jawoongo

Background

Jawoongo is an herbal mixture used in traditional medicine to treat skin diseases. This study aimed to investigate whether Jawoongo ameliorates Atopic dermatitis (AD)-like pathology in mice and to understand its underlying cellular mechanisms.

Methods

AD was induced by 2, 4-Dinitrocholrlbenzene (DNCB) in BALB/c mice. Treatment with Jawoongo was assessed to study the effect of Jawoongo on AD in mice. Histological Analysis, blood analysis, RT-PCR, western blot analysis, ELISA assay and cell viability assay were performed to verify the inhibitory effect of Jawoongo on AD in mice.

Results

We found that application of Jawoongo in an ointment form on AD-like skin lesions on DNCB-exposed BALB/c mice reduced skin thickness and ameliorated skin infiltration with inflammatory cells, mast cells and CD4+ cells. The ointment also reduced the mRNA levels of IL-2, IL-4, IL-13 and TNF-α in the sensitized skin. Leukocyte counts and the levels of IgE, IL-6, IL-10 and IL-12 were decreased in the blood of the DNCB-treated mice. Furthermore, studies on cultured cells demonstrated that Jawoongo exhibits anti-inflammatory activities, including the suppression of proinflammatory cytokine expression, nitric oxide (NO) production, and inflammation-associated molecule levels in numerous types of agonist-stimulated innate immune cell, including human mast cells (HMC-1), murine macrophage RAW264.7 cells, and splenocytes isolated from mice.

Conclusion

These findings indicate that Jawoongo alleviates DNCB-induced AD-like symptoms via the modulation of several inflammatory responses, indicating that Jawoongo might be a useful drug for the treatment of AD.

Electronic supplementary material

The online version of this article (10.1186/s12906-018-2280-z) contains supplementary material, which is available to authorized users.

Insight on the regulation of chemokine activities

The activity of chemokines is regulated by several mechanisms that control the final cellular response. The present review discusses the complexity of the regulation of the chemokine system, and the novel findings describing how in persistent infections, the expression of chemokine receptors on the surface of T cells does not correlate with their homing potential. Thanks to the latest advances in our comprehension of the chemokine system, novel approaches targeting chemokines, chemokine receptors, or protein of their signaling pathway should be considered in order to achieve a personalized therapy.

Association of highly active antiretroviral treatment with incident tuberculosis in people living with HIV/AIDS

PURPOSE

To determine the short-term and long-term effects of highly active antiretroviral therapy (HAART) on incident tuberculosis (TB) in people living with HIV/AIDS (PLWHA).

METHODS

From 2000 to 2012, we identified adult PLWHA from Taiwan Centers for Disease Control HIV Surveillance System. All PLWHA were followed up until December 31, 2012, and observed for TB occurrence. Time-dependent Cox proportional hazards models were used to determine the short-term and long-term effects of HAART on incident TB.

RESULTS

Of 20,072 PLWHA, 628 (3.13%) had incident TB, corresponding to an incident rate of 701/100,000 person-years. After adjusting for potential confounders, PLWHA receiving HAART were more likely to develop TB than those not receiving the drugs (adjusted hazard ratio [AHR] 1.56; 95% confidence interval [CI] 1.18-2.05). While the short-term and long-term effects of HAART on incident TB were considered, HAART was a risk factor for TB development within the first 90 days (AHR 6.06; 95% CI 4.58-8.01) and between 90 and 180 days of treatment (AHR 1.80; 95% CI 1.11-2.94) but was a protective factor after 180 days of HAART use (AHR 0.51; 95% CI 0.39-0.66).

CONCLUSIONS

HAART is a risk factor for the development of TB in the short term but a protective factor in the long term.

Probiotic supplementation promotes a reduction in T-cell activation, an increase in Th17 frequencies, and a recovery of intestinal epithelium integrity and mitochondrial morphology in ART-treated HIV-1-positive patients

INTRODUCTION

HIV infection is characterized by a persistent immune activation associated to a compromised gut barrier immunity and alterations in the profile of the fecal flora linked with the progression of inflammatory symptoms. The effects of high concentration multistrain probiotic (Vivomixx®, Viale del Policlinico 155, Rome, Italy in EU; Visbiome®, Dupont, Madison, Wisconsin in USA) on several aspects of intestinal immunity in ART-experienced HIV-1 patients was evaluated.

METHODS

A sub-study of a longitudinal pilot study was performed in HIV-1 patients who received the probiotic supplement twice a day for 6 months (T6). T-cell activation and CD4+ and CD8+ T-cell subsets expressing IFNγ (Th1, Tc1) or IL-17A (Th17, Tc17) were stained by cytoflorimetric analysis. Histological and immunohistochemical analyses were performed on intestinal biopsies while enterocytes apoptosis index was determined by TUNEL assay.

RESULTS

A reduction in the frequencies of CD4+ and CD8+ T-cell subsets, expressing CD38+ , HLA-DR+ , or both, and an increase in the percentage of Th17 cell subsets, especially those with central or effector memory phenotype, was recorded in the peripheral blood and in gut-associated lymphoid tissue (GALT) after probiotic intervention. Conversely, Tc1 and Tc17 levels remained substantially unchanged at T6, while Th1 cell subsets increase in the GALT. Probiotic supplementation was also associated to a recovery of the integrity of the gut epithelial barrier, a reduction of both intraepithelial lymphocytes density and enterocyte apoptosis and, an improvement of mitochondrial morphology sustained in part by a modulation of heat shock protein 60.

CONCLUSIONS

These findings highlight the potential beneficial effects of probiotic supplementation for the reconstitution of physical and immunological integrity of the mucosal intestinal barrier in ART-treated HIV-1-positive patients.

Mechanisms of Virologic Control and Clinical Characteristics of HIV+ Elite/Viremic Controllers

Human immunodeficiency virus type 1 (HIV-1) disease is pandemic, with approximately 36 million infected individuals world-wide. For the vast majority of these individuals, untreated HIV eventually causes CD4+ T cell depletion and profound immunodeficiency, resulting in morbidity and mortality. But for a remarkable few (0.2 to 0.5 percent), termed elite controllers (ECs), viral loads (VLs) remain suppressed to undetectable levels (< 50 copies/ml) and peripheral CD4+ T cell counts remain high (200 to 1000/μl), all in the absence of antiretroviral therapy (ART). Viremic controllers (VCs) are a similar but larger subset of HIV-1 infected individuals who have the ability to suppress their VLs to low levels. These patients have been intensively studied over the last 10 years in order to determine how they are able to naturally control HIV in the absence of medications, and a variety of mechanisms have been proposed. Defective HIV does not explain the clinical status of most ECs/VCs; rather these individuals appear to somehow control HIV infection, through immune or other unknown mechanisms. Over time, many ECs and VCs eventually lose the ability to control HIV, leading to CD4+ T cell depletion and immunologic dysfunction in the absence of ART. Elucidating novel mechanisms of HIV control in this group of patients will be an important step in understanding HIV infection. This will extend our knowledge of HIV-host interaction and may pave the way for the development of new therapeutic approaches and advance the cure agenda.

Modeling the Mechanisms by Which HIV-Associated Immunosuppression Influences HPV Persistence at the Oral Mucosa

Human immunodeficiency virus (HIV)-infected patients are at an increased risk of co-infection with human papilloma virus (HPV), and subsequent malignancies such as oral cancer. To determine the role of HIV-associated immune suppression on HPV persistence and pathogenesis, and to investigate the mechanisms underlying the modulation of HPV infection and oral cancer by HIV, we developed a mathematical model of HIV/HPV co-infection. Our model captures known immunological and molecular features such as impaired HPV-specific effector T helper 1 (Th1) cell responses, and enhanced HPV infection due to HIV. We used the model to determine HPV prognosis in the presence of HIV infection, and identified conditions under which HIV infection alters HPV persistence in the oral mucosa system. The model predicts that conditions leading to HPV persistence during HIV/HPV co-infection are the permissive immune environment created by HIV and molecular interactions between the two viruses. The model also determines when HPV infection continues to persist in the short run in a co-infected patient undergoing antiretroviral therapy. Lastly, the model predicts that, under efficacious antiretroviral treatment, HPV infections will decrease in the long run due to the restoration of CD4+ T cell numbers and protective immune responses.

HIV persists in CCR6+CD4+ T cells from colon and blood during antiretroviral therapy

OBJECTIVES

The objective of this article is to investigate the contribution of colon and blood CD4 T-cell subsets expressing the chemokine receptor CCR6 to HIV persistence during antiretroviral therapy.

DESIGN

Matched sigmoid biopsies and blood samples (n = 13) as well as leukapheresis (n = 20) were collected from chronically HIV-infected individuals receiving antiretroviral therapy. Subsets of CD4 T cells with distinct differentiation/polarization profiles were identified using surface markers as follows: memory (TM, CD45RA), central memory (TCM; CD45RACCR7), effector (TEM/TM; CD45RACCR7), Th17 (CCR6CCR4), Th1Th17 (CCR6CXCR3), Th1 (CCR6CXCR3), and Th2 (CCR6CCR4).

METHODS

We used polychromatic flow cytometry for cell sorting, nested real-time PCR for HIV DNA quantification, ELISA and flow cytometry for HIV p24 quantification. HIV reactivation was induced by TCR triggering in the presence/absence of all-trans retinoic acid.

RESULTS

Compared with blood, the frequency of CCR6 TM was higher in the colon. In both colon and blood compartments, CCR6 TM were significantly enriched in HIV DNA when compared with their CCR6 counterparts (n = 13). In blood, integrated HIV DNA levels were significantly enriched in CCR6 versus CCR6 TCM of four of five individuals and CCR6 versus CCR6 TEM of three of five individuals. Among blood TCM, Th17 and Th1Th17 contributed the most to the pool of cells harboring integrated HIV DNA despite their reduced frequency compared with Th2, which were infected the least. HIV reactivation was induced by TCR triggering and/or retinoic acid exposure at higher levels in CCR6 versus CCR6 TM, TCM, and TEM.

CONCLUSION

CCR6 is a marker for colon and blood CD4 T cells enriched for replication-competent HIV DNA. Novel eradication strategies should target HIV persistence in CCR6CD4 T cells from various anatomic sites.

Impairment of CCR6+ and CXCR3+ Th Cell Migration in HIV-1 Infection Is Rescued by Modulating Actin Polymerization

CD4+ T cell repopulation of the gut is rarely achieved in HIV-1-infected individuals who are receiving clinically effective antiretroviral therapy. Alterations in the integrity of the mucosal barrier have been indicated as a cause for chronic immune activation and disease progression. In this study, we present evidence that persistent immune activation causes impairment of lymphocytes to respond to chemotactic stimuli, thus preventing their trafficking from the blood stream to peripheral organs. CCR6+ and CXCR3+ Th cells accumulate in the blood of aviremic HIV-1-infected patients on long-term antiretroviral therapy, and their frequency in the circulation positively correlates to levels of soluble CD14 in plasma, a marker of chronic immune activation. Th cells show an impaired response to chemotactic stimuli both in humans and in the pathogenic model of SIV infection, and this defect is due to hyperactivation of cofilin and inefficient actin polymerization. Taking advantage of a murine model of chronic immune activation, we demonstrate that cytoskeleton remodeling, induced by okadaic acid, restores lymphocyte migration in response to chemokines, both in vitro and in vivo. This study calls for novel pharmacological approaches in those pathological conditions characterized by persistent immune activation and loss of trafficking of T cell subsets to niches that sustain their maturation and activities.

Effect of Antiretroviral Therapy on the Memory and Activation Profiles of B Cells in HIV-Infected African Women

Human immunodeficiency virus infection induces a wide range of effects in B cells, including skewed memory cell differentiation, compromised B cell function, and hypergammaglobulinemia. However, data on the extent to which these B cell abnormalities can be reversed by antiretroviral therapy (ART) are limited. To investigate the effect of ART on B cells, the activation (CD86) and differentiation (IgD, CD27, and CD38) profiles of B cells were measured longitudinally in 19 HIV-infected individuals before (median, 2 mo) and after ART initiation (median, 12 mo) and compared with 19 age-matched HIV-uninfected individuals using flow cytometry. Twelve months of ART restored the typical distribution of B cell subsets, increasing the proportion of naive B cells (CD27^-IgD⁺CD38^-) and concomitantly decreasing the immature transitional (CD27^-IgD⁺CD38⁺), unswitched memory (CD27⁺IgD⁺CD38^-), switched memory (CD27⁺IgD^-CD38^- or CD27^-IgD^-CD38^-), and plasmablast (CD27⁺IgD^-CD38^high) subsets. However, B cell activation was only partially normalized post-ART, with the frequency of activated B cells (CD86⁺CD40⁺) reduced compared with pre-ART levels (p = 0.0001), but remaining significantly higher compared with HIV-uninfected individuals (p = 0.0001). Interestingly, unlike for T cell activation profiles, the extent of B cell activation prior to ART did not correlate with HIV plasma viral load, but positively associated with plasma sCD14 levels (p = 0.01, r = 0.58). Overall, ART partially normalizes the skewed B cell profiles induced by HIV, with some activation persisting. Understanding the effects of HIV on B cell dysfunction and restoration following ART may provide important insights into the mechanisms of HIV pathogenesis.

A Summary of the First HIV Microbiome Workshop 2015

The role of microbiota in the pathogenesis of HIV infection has become the subject of intense research in recent years. A rapidly growing amount of data suggest that microbial dysbiosis-in the gut or the genital tract-can influence HIV transmission and/or disease progression; however, a deeper understanding of the mechanisms involved is lacking. To better understand the relationship between the microbiome and HIV infection, investigators from a wide variety of disciplines, including those working in basic and clinical HIV studies, cardiovascular disease, reproductive health, and bioinformatics, gathered at the first International Workshop on Microbiome in HIV Pathogenesis, Prevention and Treatment, at NIH on 7 and 8 April, 2015.

Gut barrier structure, mucosal immunity and intestinal microbiota in the pathogenesis and treatment of HIV infection

Over the past 10 years, extensive work has been carried out in the field of microbial translocation in HIV infection, ranging from studies on its clinical significance to investigations on its pathogenic features. In the present work, we review the most recent findings on this phenomenon, focusing on the predictive role of microbial translocation in HIV-related morbidity and mortality, the mechanisms by which it arises and potential therapeutic approaches. From a clinical perspective, current work has shown that markers of microbial translocation may be useful in predicting clinical events in untreated HIV infection, while conflicting data exist on their role in cART-experienced subjects, possibly due to the inclusion of extremely varied patient populations in cohort studies. Results from studies addressing the pathogenesis of microbial translocation have improved our knowledge of the damage of the gastrointestinal epithelial barrier occurring in HIV infection. However, the extent to which mucosal impairment translates directly to increased gastrointestinal permeability remains an open issue. In this respect, novel work has established a role for IL-17 and IL-22-secreting T cell populations in limiting microbial translocation and systemic T-cell activation/inflammation, thus representing a possible target of immune-therapeutic interventions shown to be promising in the animal model. Further, recent reports have not only confirmed the presence of a dysbiotic intestinal community in the course of HIV infection but have also shown that it may be linked to mucosal damage, microbial translocation and peripheral immune activation. Importantly, technical advances have also shed light on the metabolic activity of gut microbes, highlighting the need for novel therapeutic approaches to correct the function, as well as the composition, of the gastrointestinal microbiota.

Dominant enrichment of phenotypically activated CD38(+) HLA-DR(+) CD8(+) T cells, rather than CD38(+) HLA-DR(+) CD4(+) T cells, in HIV/HCV coinfected patients on antiretroviral therapy

HIV infection may enhance immune-activation, while little is known regarding the role of HCV infection. This study investigates the impact of HCV in HIV coinfected patients with undetectable viraemia under HAART on the levels of peripheral T cell's immune-activation. We determined T lymphocytes subsets to characterize immune-activation defined as CD38 and/or HLA-DR expression in chronic monoinfected HCV, HIV, and HIV/HCV coinfected subjects. One hundred and fifty six patients were divided into three groups: (i) 77 HIV+ patients; (ii) 50 HCV+ patients; and (iii) 29 coinfected HIV/HCV patients. The level of CD4(+) was significantly higher in HCV+ than in HIV+ or in coinfected HIV/HCV subjects. The frequencies of CD4(+) CD38(+) /HLA-DR(-) , CD4(+) CD38(-) /HLA-DR(+) and CD4(+) CD38(+) /HLA-DR(+) in HIV+ patients were comparable to those measured in coinfected patients, but statistically higher than those observed in HCV+ subjects. The percentage of CD8(+) was comparable in HIV-1+ patients and coinfected HIV/HCV but the results obtained in both groups were significantly higher compared to the results obtained in HCV patients. The level of CD8(+) CD38(+) /HLA-DR(-) showed values lower in HIV+ patients than in that monoinfected HCV and coinfected HIV/HCV patients. The frequencies of CD8(+) CD38(-) /HLA-DR(+) were higher in HIV+ patients compared to HCV+ and coinfected HIV/HCV patients. HIV/HCV coinfected group showed highest levels of CD8(+) CD38(+) /HLA-DR(+) . HIV plays a pivotal role to determine the immune activation in the host. The role of HCV needs of further investigations but our data show that HCV mainly influences the immune-activation of the pool of CD8, but also probably plays a supporting additive effect on CD4 immune-activation. J. Med. Virol. 88:1347-1356, 2016. © 2016 Wiley Periodicals, Inc.

Identification of novel HIV-1 dependency factors in primary CCR4(+)CCR6(+)Th17 cells via a genome-wide transcriptional approach

BACKGROUND

The HIV-1 infection is characterized by profound CD4(+) T cell destruction and a marked Th17 dysfunction at the mucosal level. Viral suppressive antiretroviral therapy restores Th1 but not Th17 cells. Although several key HIV dependency factors (HDF) were identified in the past years via genome-wide siRNA screens in cell lines, molecular determinants of HIV permissiveness in primary Th17 cells remain to be elucidated.

RESULTS

In an effort to orient Th17-targeted reconstitution strategies, we investigated molecular mechanisms of HIV permissiveness in Th17 cells. Genome-wide transcriptional profiling in memory CD4(+) T-cell subsets enriched in cells exhibiting Th17 (CCR4(+)CCR6(+)), Th1 (CXCR3(+)CCR6(-)), Th2 (CCR4(+)CCR6(-)), and Th1Th17 (CXCR3(+)CCR6(+)) features revealed remarkable transcriptional differences between Th17 and Th1 subsets. The HIV-DNA integration was superior in Th17 versus Th1 upon exposure to both wild-type and VSV-G-pseudotyped HIV; this indicates that post-entry mechanisms contribute to viral replication in Th17. Transcripts significantly enriched in Th17 versus Th1 were previously associated with the regulation of TCR signaling (ZAP-70, Lck, and CD96) and Th17 polarization (RORγt, ARNTL, PTPN13, and RUNX1). A meta-analysis using the NCBI HIV Interaction Database revealed a set of Th17-specific HIV dependency factors (HDFs): PARG, PAK2, KLF2, ITGB7, PTEN, ATG16L1, Alix/AIP1/PDCD6IP, LGALS3, JAK1, TRIM8, MALT1, FOXO3, ARNTL/BMAL1, ABCB1/MDR1, TNFSF13B/BAFF, and CDKN1B. Functional studies demonstrated an increased ability of Th17 versus Th1 cells to respond to TCR triggering in terms of NF-κB nuclear translocation/DNA-binding activity and proliferation. Finally, RNA interference studies identified MAP3K4 and PTPN13 as two novel Th17-specific HDFs.

CONCLUSIONS

The transcriptional program of Th17 cells includes molecules regulating HIV replication at multiple post-entry steps that may represent potential targets for novel therapies aimed at protecting Th17 cells from infection and subsequent depletion in HIV-infected subjects.

Analysis of Th17 and Tc17 Frequencies and Antiviral Defenses in Gut-Associated Lymphoid Tissue of Chronic HIV-1 Positive Patients

The complex relationship between both the Th1/Th17 and Tc1/Tc17 axis and innate defences in the intestinal mucosa during HIV-1 infection has not been well characterized. This study examined the frequency, phenotype, and functional status of T cell populations in the gut-associated lymphoid tissue and peripheral blood of virologically suppressed HIV-1-infected patients on therapy, focusing on the Th1, Th17, Tc1, and Tc17 cell subsets. We found a persistent immune cell activation (CD38 and HLADR expression) into the GALT despite the higher levels of Th17 and Tc17 in respect to peripheral blood. An upregulation of type I IFN response in GALT compared to the peripheral blood compartment was also recorded. Furthermore, IFN-α/β levels were negatively related to the frequencies of Th1 naïve cells and Tc1 cell subsets (naïve, central memory, and effector memory) in the GALT. In contrast, no relationships between type I IFN response and Th1 or Tc1 cell subsets in peripheral blood compartment and between IFN-α/β and Th17/Tc17 in both GALT and peripheral blood district were recorded. These data indicate that prolonged antiretroviral treatment improves GALT immune function despite the persistence of immune activation and type I IFN response in chronic HIV-1 positive patients.

Differential effects of viremia and microbial translocation on immune activation in HIV-infected patients throughout ritonavir-boosted darunavir monotherapy

The purpose of this article is to evaluate the evolution of microbial translocation (MT) and its role in CD4 and CD8 T cells immune activation (IA) in HIV-1-infected patients on ritonavir-boosted darunavir monotherapy (mtDRV/rtv).Prospective study of consecutive HIV-1-infected patients switched to mtDRV/rtv as a simplification regimen. Subjects were classified according to the virological behavior during a 24-month follow-up as continuous undetectable viral load, blips, intermittent viremia, and virological failure (VF). MT was evaluated by plasma LPS and 16S genomic rDNA (16S rDNA) levels, whereas IA was assessed by the coexpression of HLA-DR and CD38 in CD4 and CD8 T cells, and plasma sCD14 levels.Seventy-one patients were included in this substudy of the MonDar cohort (ClinicalTrials.gov: NCT01505722). At baseline, CD4 (ρ = -0.352, P = 0.01) and CD8 T-cell activation (ρ = -0.468, P < 0.001) were correlated with time with viral suppression, but not with MT markers. A significant decrease in plasma LPS levels was found only in patients without VF (baseline, 77.8 vs month 24, 60.4 pg/mL; P < 0.001]. Both plasma 16S rDNA and sCD14 levels were unchanged irrespective of the viral behavior. The only variable independently associated with a decrease in CD4 and CD8 T cells activation was an undetectable HIV-1 viremia (β = 4.78, P < 0.001 and β = 2.93, P = 0.005, respectively).MT does not have a pivotal role in T-cell activation, at least in patients with long-term viral suppression. The viremic episodes and VF are the main factors related to CD4 and CD8 T-cells IA, even during mtDRV/rtv.

A novel non-integrative single-cycle chimeric HIV lentivector DNA vaccine

Novel HIV vaccine vectors and strategies are needed to control HIV/AIDS epidemic in humans and eradicate the infection. DNA vaccines alone failed to induce immune responses robust enough to control HIV-1. Development of lentivirus-based DNA vaccines deficient for integration and with a limited replication capacity is an innovative and promising approach. This type of vaccine mimics the early stages of virus infection/replication like the live-attenuated viruses but lacks the inconvenient integration and persistence associated with disease. We developed a novel lentivector DNA vaccine "CAL-SHIV-IN(-)" that undergoes a single round of replication in the absence of integration resulting in augmented expression of vaccine antigens in vivo. Vaccine gene expression is under control of the LTRs of a naturally attenuated lentivirus, Caprine arthritis encephalitis virus (CAEV) the natural goat lentivirus. The safety of this vaccine prototype was increased by the removal of the integrase coding sequences from the pol gene. We examined the functional properties of this lentivector DNA in cell culture and the immunogenicity in mouse models. Viral proteins were expressed in transfected cells, assembled into viral particles that were able to transduce once target permissive cells. Unlike the parental replication-competent SHIV-KU2 that was detected in DNA samples from any of the serial passage infected cells, CAL-SHIV-IN(-) DNA was detected only in target cells of the first round of infection, hence demonstrating the single cycle replication of the vaccine. A single dose DNA immunization of humanized NOD/SCID/β2 mice showed a substantial increase of IFN-γ-ELISPOT in splenocytes compared to the former replication and integration defective Δ4SHIV-KU2 DNA vaccine.