Reduced thymic output is a major mechanism of immune reconstitution failure in HIV-infected patients after long-term antiretroviral therapy

Enhanced immune reconstitution with albuvirtide in HIV-infected immunological non-responders

Background

Incomplete immune recovery in people living with HIV/AIDS (PLWHA) remains an important clinical challenge with the lack of an effective strategy currently available to restore their T-cell immune response. This study aimed to evaluate the effect of Albuvirtide (ABT) on immune recovery in immunological non-responders (INRs) and attempted to explore potential mechanisms of ABT on the functionality of immune cells.

Methods

In this prospective, open-label, controlled clinical study, participants with incomplete immune reconstitution (continuous ART over 5 years and CD4+T lymphocyte absolute count of <500 cells/µl or ART for 2-5 years and CD4+T cell count of <200 cells/µl with undetectable viral load) were received intensive treatment with ABT or maintained on the original ART regimen at a ratio of 1:1. Immune response and safety were examined within 24 weeks. In the cytological study, T subsets, cell apoptosis and cell autophagy were analyzed using immunofluorescence staining and flow cytometry from 25 blood specimens.

Results

Both groups (n=25 each) were comparable in age, gender, and ART duration. At week 12, CD4+T cell count increased significantly in the intensive ABT group compared with control group (the change from baseline in CD4+T cell count: 45 vs. -5 cells/µL, p<0.001). After ABT discontinuation, CD4+T cell counts remained significantly higher in the intensive ABT group at week 24 (55 vs. -5 cells/µL, p=0.012). In laboratory analysis, naïve CD4+ T cell amounts were lowest among participants with unsatisfactory immune response (uIR) to ABT (p=0.001). The proportion of caspase 3+CD45RA+CD31+CD4+ T cells was significantly lower in participants with satisfactory immune response (sIR) to ABT (p<0.05).

Conclusion

Significant CD4+T cell count increase suggests ABT enhances immune function in INRs which may be attributed to its antiviral properties as well as its ability to increase thymic cell output and decrease cell apoptosis.

Transcriptionally Active Defective HIV-1 Proviruses and Their Association With Immunological Nonresponse to Antiretroviral Therapy

A subset of antiretroviral therapy-treated persons with human immunodeficiency virus (HIV), referred to as immunological nonresponders (INRs), fails to normalize CD4+ T-cell numbers. In a case-control study involving 26 INRs (CD4 < 250 cells/µL) and 25 immunological responders (IRs; CD4 ≥ 250 cells/µL), we evaluated the potential contribution of transcriptionally competent defective HIV-1 proviruses to poor CD4+ T-cell recovery. Compared to the responders, the INRs had higher levels of cell-associated HIV RNA (P = .034) and higher percentages of HLA-DR+ CD4+ T cells (P < .001). While not encoding replication-competent viruses, the RNA transcripts frequently encoded HIV-1 Gag-p17 and Nef proteins. These transcripts and/or resulting proteins may activate pathway(s) leading to the immunological nonresponse phenotype.

Exercise to Prevent Accelerated Vascular Aging in People Living With HIV

Given advances in antiretroviral therapy, the mortality rate for HIV infection has dropped considerably over recent decades. However, people living with HIV (PLWH) experience longer life spans coupled with persistent immune activation despite viral suppression and potential toxicity from long-term antiretroviral therapy use. Consequently, PLWH face a cardiovascular disease (CVD) risk more than twice that of the general population, making it the leading cause of death among this group. Here, we briefly review the epidemiology of CVD in PLWH highlighting disparities at the intersections of sex and gender, age, race/ethnicity, and the contributions of social determinants of health and psychosocial stress to increased CVD risk among individuals with marginalized identities. We then overview the pathophysiology of HIV and discuss the primary factors implicated as contributors to CVD risk among PLWH on antiretroviral therapy. Subsequently, we highlight the functional evidence of premature vascular dysfunction as an early pathophysiological determinant of CVD risk among PLWH, discuss several mechanisms underlying premature vascular dysfunction in PLWH, and synthesize current research on the pathophysiological mechanisms underlying accelerated vascular aging in PLWH, focusing on immune activation, chronic inflammation, and oxidative stress. We consider understudied aspects such as HIV-related changes to the gut microbiome and psychosocial stress, which may serve as mechanisms through which exercise can abrogate accelerated vascular aging. Emphasizing the significance of exercise, we review various modalities and their impacts on vascular health, proposing a holistic approach to managing CVD risks in PLWH. The discussion extends to critical future study areas related to vascular aging, CVD, and the efficacy of exercise interventions, with a call for more inclusive research that considers the diversity of the PLWH population.

Transcriptomic crosstalk between viral and host factors drives aberrant homeostasis of T-cell proliferation and cell death in HIV-infected immunological non-responders

BACKGROUND

Immunological non-responders (INRs) among people living with HIV have inherently higher mortality and morbidity rates. The underlying immunological mechanisms whereby failure of immune reconstitution occurs in INRs require elucidation.

METHOD

HIV-1 DNA and HIV-1 cell-associated RNA (CA-HIV RNA) quantifications were conducted via RT-qPCR. Transcriptome sequencing (RNA-seq), bioinformatics, and biological verifications were performed to discern the crosstalk between host and viral factors. Flow cytometry was employed to analyze cellular activation, proliferation, and death.

RESULTS

HIV-1 DNA and CA-HIV RNA levels were observed to be significantly higher in INRs compared to immunological responders (IRs). Evaluation of CD4/CD8 ratios showed a significantly negative correlation with HIV-1 DNA in IRs, but not in INRs. Bioinformatics analyses and biological verifications showed IRF7/INF-α regulated antiviral response was intensified in INRs. PBMCs of INRs expressed significantly more HIV integrase-mRNA (p31) than IRs. Resting (CD4+CD69- T-cells) and activated (CD4+CD69+ T-cells) HIV-1 reservoir harboring cells were significantly higher in INRs, with the co-occurrence of significantly higher cellular proliferation and cell death in CD4+ T-cells of INRs.

CONCLUSION

In INRs, the systematic crosstalk between the HIV-1 reservoir and host cells tends to maintain a persistent antiviral response-associated inflammatory environment, which drives aberrant cellular activation, proliferation, and death of CD4+ T-cells.

Role of thymosin α1 in restoring immune response in immunological nonresponders living with HIV

BACKGROUND

Immunological nonresponders (INRs) living with HIV are at increased risk of co-infection and multiple tumors, with no effective strategy currently available to restore their T-cell immune response. This study aimed to explore the safety and efficacy of thymosin α1 in reconstituting the immune response in INRs.

METHODS

INRs with CD4 + T cell counts between 100 and 350 cells/μL were enrolled and received two-staged 1.6 mg thymosin α1 subcutaneous injections for 24 weeks (daily in the first 2 weeks and biweekly in the subsequent 22 weeks) while continuing antiretroviral therapy. T cell counts and subsets, the expression of PD-1 and TIM-3 on T cells, and signal joint T cell receptor excision circles (sjTREC) at week 24 were evaluated as endpoints.

RESULTS

Twenty three INRs were screened for eligibility, and 20 received treatment. The majority were male (19/20), with a median age of 48.1 years (interquartile range: 40.5-57.0) and had received antiretroviral therapy for 5.0 (3.0, 7.3) years. Multiple comparisons indicated that CD4 + T cell count and sjTREC increased after initiation of treatment, although no significant differences were observed at week 24 compared to baseline. Greatly, levels of CD4 + T cell proportion (17.2% vs. 29.1%, P < 0.001), naïve CD4 + and CD8 + T cell proportion (17.2% vs. 41.1%, P < 0.001; 13.8% vs. 26.6%, P = 0.008) significantly increased. Meanwhile, the proportion of CD4 + central memory T cells of HIV latent hosts (42.7% vs. 10.3%, P < 0.001) significantly decreased. Moreover, the expression of PD-1 on CD4 + T cells (14.1% vs. 6.5%, P < 0.001) and CD8 + T cells (8.5% vs. 4.1%, P < 0.001) decreased, but the expression of TIM-3 on T cellsremained unaltered at week 24. No severe adverse events were reported and HIV viral loads kept stable throughout the study.

CONCLUSIONS

Thymosin α1 enhance CD4 + T cell count and thymic output albeit as a trend rather than an endpoint. Importantly, it improves immunosenescence and decreases immune exhaustion, warranting further investigation.

TRIAL REGISTRATION

This single-arm prospective study was registered with ClinicalTrials.gov (NCT04963712) on July 15, 2021.

Distinct inflammation-related proteins associated with T cell immune recovery during chronic HIV-1 infection

Chronic inflammation and T cell dysregulation persist in individuals infected with human immunodeficiency virus type 1 (HIV-1), even after successful antiretroviral treatment. The mechanism involved is not fully understood. Here, we used Olink proteomics to comprehensively analyze the aberrant inflammation-related proteins (IRPs) in chronic HIV-1-infected individuals, including in 24 treatment-naïve individuals, 33 immunological responders, and 38 immunological non-responders. T cell dysfunction was evaluated as T cell exhaustion, activation, and differentiation using flow cytometry. We identified a cluster of IRPs (cluster 7), including CXCL11, CXCL9, TNF, CXCL10, and IL18, which was closely associated with T cell dysregulation during chronic HIV-1 infection. Interestingly, IRPs in cluster 5, including ST1A1, CASP8, SIRT2, AXIN1, STAMBP, CD40, and IL7, were negatively correlated with the HIV-1 reservoir size. We also identified a combination of CDCP1, CXCL11, CST5, SLAMF1, TRANCE, and CD5, which may be useful for distinguishing immunological responders and immunological non-responders. In conclusion, the distinct inflammatory milieu is closely associated with immune restoration of T cells, and our results provide insight into immune dysregulation during chronic HIV-1 infection.

Pillars of long-term antiretroviral therapy success

BACKGROUND

Meeting the challenge of antiretroviral therapy (ART) whose efficacy can last a lifetime requires continuous updating of the virological, pharmacological, and quality of life outcomes to be pursued and a continuous review of literature data on the efficacy and tolerability of new drugs and therapeutic strategies.

METHODS

With the aim of identifying open questions and answers about the current controversies in modern ART, we adapted the Design Thinking methodology to the needs of the design phase of a scientific article, involving a team of experts in HIV care.

RESULTS

Five main pillars of treatment success were discussed: sustained virologic suppression over time; immunological recovery; pharmacological attributes; long-term tolerability and safety of ART; and people's satisfaction and quality of life. The definition of the outcomes to be achieved in each thematic area and the tools to achieve them were reviewed and discussed.

CONCLUSIONS

Long-term treatment success should be intended as a combination of HIV-RNA suppression, immune recovery, and high quality of life. To achieve this, the regimen should be well-tolerated, with high potency, genetic barrier, and forgiveness, and should be tailored by a person-centered perspective, based on individual needs, preferences, and therapeutic history.

Metformin may be a viable adjunctive therapeutic option to potentially enhance immune reconstitution in HIV-positive immunological non-responders

ABSTRACT

Incomplete immune reconstitution remains a global challenge for human immunodeficiency virus (HIV) treatment in the present era of potent antiretroviral therapy (ART), especially for those individuals referred to as immunological non-responders (INRs), who exhibit dramatically low CD4 + T-cell counts despite the use of effective antiretroviral therapy, with long-term inhibition of viral replication. In this review, we provide a critical overview of the concept of ART-treated HIV-positive immunological non-response, and also explain the known mechanisms which could potentially account for the emergence of immunological non-response in some HIV-infected individuals treated with appropriate and effective ART. We found that immune cell exhaustion, combined with chronic inflammation and the HIV-associated dysbiosis syndrome, may represent strategic aspects of the immune response that may be fundamental to incomplete immune recovery. Interestingly, we noted from the literature that metformin exhibits properties and characteristics that may potentially be useful to specifically target immune cell exhaustion, chronic inflammation, and HIV-associated gut dysbiosis syndrome, mechanisms which are now recognized for their critically important complicity in HIV disease-related incomplete immune recovery. In light of evidence discussed in this review, it can be seen that metformin may be of particularly favorable use if utilized as adjunctive treatment in INRs to potentially enhance immune reconstitution. The approach described herein may represent a promising area of therapeutic intervention, aiding in significantly reducing the risk of HIV disease progression and mortality in a particularly vulnerable subgroup of HIV-positive individuals.

Recent advances in poor HIV immune reconstitution: what will the future look like?

Combination antiretroviral therapy has demonstrated proved effectiveness in suppressing viral replication and significantly recovering CD4+ T cell count in HIV type-1 (HIV-1)-infected patients, contributing to a dramatic reduction in AIDS morbidity and mortality. However, the factors affecting immune reconstitution are extremely complex. Demographic factors, co-infection, baseline CD4 cell level, abnormal immune activation, and cytokine dysregulation may all affect immune reconstitution. According to report, 10-40% of HIV-1-infected patients fail to restore the normalization of CD4+ T cell count and function. They are referred to as immunological non-responders (INRs) who fail to achieve complete immune reconstitution and have a higher mortality rate and higher risk of developing other non-AIDS diseases compared with those who achieve complete immune reconstitution. Heretofore, the mechanisms underlying incomplete immune reconstitution in HIV remain elusive, and INRs are not effectively treated or mitigated. This review discusses the recent progress of mechanisms and factors responsible for incomplete immune reconstitution in AIDS and summarizes the corresponding therapeutic strategies according to different mechanisms to improve the individual therapy.

Thymic Exhaustion and Increased Immune Activation Are the Main Mechanisms Involved in Impaired Immunological Recovery of HIV-Positive Patients under ART

Decades of studies in antiretroviral therapy (ART) have passed, and the mechanisms that determine impaired immunological recovery in HIV-positive patients receiving ART have not been completely elucidated yet. Thus, T-lymphocytes immunophenotyping and cytokines levels were analyzed in 44 ART-treated HIV-positive patients who had a prolonged undetectable plasma viral load. The patients were classified as immunological non-responders (INR = 13) and immunological responders (IR = 31), according to their CD4+ T cell levels. Evaluating pre-CD4+ levels, we observed a statistically significant trend between lower CD4+ T cell levels and INR status (Z = 3.486, p < 0.001), and during 18 months of ART, the CD4+ T cell levels maintained statistical differences between the INR and IR groups (WTS = 37.252, p < 0.001). Furthermore, the INRs were associated with an elevated age at ART start; a lower pre-treatment CD4+ T cell count and a percentage that remained low even after 18 months of ART; lower levels of recent thymic emigrant (RTE) CD4+ T cell (CD45RA + CD31+) and a naïve CD4+ T cell (CD45RA + CD62L+); higher levels of central memory CD4+ T cells (CD45RA-CD62L+); and higher immune activation by CD4+ expressing HLA-DR+ or both (HLA-DR+ and CD38+) when compared with IRs. Our study demonstrates that thymic exhaustion and increased immune activation are two mechanisms substantially implicated in the impaired immune recovery of ART-treated HIV patients.

CD4+ T lymphocyte recovery in the modern antiretroviral therapy era: Toward a new threshold for defining immunological non-responders

Introduction

Despite the high level of efficacy of modern antiretroviral therapy (ART) in reducing HIV viremia and the control of viral replication, some people living with HIV (PLWH) do not recover their CD4+ T cell count.

Methods

To evaluate the frequency and predictive factors of discordant immune responses, we performed a retrospective cohort study of 324 antiretroviral-naïve PLWH who initiated first-line ART between 2008 and 2018 and maintained HIV RNA &lt; 50 copies/ml during 36 months of follow-up. PLWH were defined as immunological non-responders (INRs) when CD4+ T cell count was &lt; 20% compared with baseline (INR20%), or &lt; 500 cells/mm3 (INR500) or &lt; 200 cells/mm3 (INR200) at 36 months.

Results

The prevalence of INR20%, INR500, and INR200 was 12.5%, 34.6%, and 1.5%, respectively. After adjustment for possible confounders, CD4 nadir showed a significant association with all INR definitions, with lower values predicting INR500 (aOR 0.98, 95% CI 0.98–0.99, p &lt; 0.001) and INR200 (aOR 0.98, 95% CI 0.95–1.01, p = 0.096). Moreover, a higher baseline CD4/CD8 ratio was inversely related to the probability of being INR500 (OR 0.03, 95% CI 0.01–0.12, p &lt; 0.001) and INR200 (OR 0.002, 95% CI 18–7–67.72, p = 0.255). By contrast, INR20% had a higher CD4 nadir and CD4/CD8 ratio than other INRs, suggesting the identification of an heterogenous population with such definition.

Discussion

The present study highlights how INR200 has become rare in the contemporary ART era, and about one-third of PLWH meet the criteria for INR500. Overcoming the threshold of 500 CD4/mm3 could be an appropriate definition of immune response, in contrast with the older definitions of INR200 and INR20%. Early diagnosis and rapid treatment initiation, before CD4 counts and the CD4/CD8 ratio begin to decline, are critical for achieving an optimal immune response.

Cellular and molecular insights into incomplete immune recovery in HIV/AIDS patients

Highly active antiretroviral therapy (ART) can effectively inhibit virus replication and restore immune function in most people living with human immunodeficiency virus (HIV). However, an important proportion of patients fail to achieve a satisfactory increase in CD4⁺ T cell counts. This state is called incomplete immune reconstitution or immunological nonresponse (INR). Patients with INR have an increased risk of clinical progression and higher rates of mortality. Despite widespread attention to INR, the precise mechanisms remain unclear. In this review, we will discuss the alterations in the quantity and quality of CD4⁺ T as well as multiple immunocytes, changes in soluble molecules and cytokines, and their relationship with INR, aimed to provide cellular and molecular insights into incomplete immune reconstitution.

The effect of age on CD4+ T-cell recovery in HIV-suppressed adult participants: a sub-study from AIDS Clinical Trial Group (ACTG) A5321 and the Bone Loss and Immune Reconstitution (BLIR) study

Older age could be a risk factor for suboptimal CD4+ T-cell recovery in HIV-infected patients despite successful viral suppression. However, evaluation of this effect could be confounded by age-related immune processes such as decreased thymus output, increased immune activation and exhaustion. Here, we established a semi-mechanistic population model simultaneously describing naïve and memory CD4+ T-cell trajectories in 122 participants. Covariate analysis accounting for immune activation showed that older age was significantly associated with faster apparent elimination rate of the naïve T-cells. In addition, female sex predicted slower apparent elimination rate of memory T-cells. Simulations showed that the median maximal CD4+ T-cell count on ART treatment was 593 cells/μL (IQR 442-794) in patients aged 50 years or above and 738 cells/μL (IQR 548-1002) in patients aged 18-35 years. The differences in the percentage of subjects achieving sufficient immune reconstitution (CD4+ T-cell count> 500 cells/μL) between the two age groups were 15, 21 and 26% at year 1, 4 years and steady state, respectively, suggesting that advanced age may have a greater impact on long-term CD4+ T-cell recovery.

Mucosal-associated invariant T cells: a cryptic coordinator in HIV-infected immune reconstitution

Human immunodeficiency virus type 1 (HIV-1) infection causes considerable morbidity and mortality worldwide. Although antiretroviral therapy (ART) has largely transformed HIV infection from a fatal disease to a chronic condition, approximately 10%~40% of HIV-infected individuals who receive effective ART and sustain long-term viral suppression still cannot achieve optimal immune reconstitution. These patients are called immunological non-responders, a state associated with poor clinical prognosis. Mucosal-associated invariant T (MAIT) cells are an evolutionarily conserved unconventional T cell subset defined by expression of semi-invariant αβ T cell receptor (TCR), which recognizes metabolites derived from the riboflavin biosynthetic pathway presented on major histocompatibility complex (MHC)-related protein-1 (MR1). MAIT cells, which are considered to act as a bridge between innate and adaptive immunity, produce a wide range of cytokines and cytotoxic molecules upon activation through TCR-dependent and TCR-independent mechanisms, which is of major importance in defense against a variety of pathogens. In addition, MAIT cells are involved in autoimmune and immune-mediated diseases. The number of MAIT cells is dramatically and irreversibly decreased in the early stage of HIV infection and is not fully restored even after long-term suppressive ART. In light of the important role of MAIT cells in mucosal immunity and because microbial translocation is inversely associated with CD4⁺ T cell counts, we propose that MAIT cells participate in the maintenance of intestinal barrier integrity and microbial homeostasis, thus further affecting immune reconstitution in HIV-infected individuals. This article is protected by copyright. All rights reserved.

Identification of Diagnostic Markers Correlated With HIV+ Immune Non-response Based on Bioinformatics Analysis

Background: HIV-infected immunological non-responders (INRs) are characterized by their inability to reconstitute CD4⁺ T cell pools after antiretroviral therapy. The risk of non-AIDS-related diseases in INRs is increased, and the outcome and prognosis of INRs are inferior to that of immunological responders (IRs). However, few markers can be used to define INRs precisely. In this study, we aim to identify further potential diagnostic markers associated with INRs through bioinformatic analyses of public datasets.

Methods: This study retrieved the microarray data sets of GSE106792 and GSE77939 from the Gene Expression Omnibus (GEO) database. After merging two microarray data and adjusting the batch effect, differentially expressed genes (DEGs) were identified. Gene Ontology (GO) resource and Kyoto Encyclopedia of Genes and Genomes (KEGG) resource were conducted to analyze the biological process and functional enrichment. We performed receiver operating characteristic (ROC) curves to filtrate potential diagnostic markers for INRs. Gene Set Enrichment Analysis (GSEA) was conducted to perform the pathway enrichment analysis of individual genes. Single sample GSEA (ssGSEA) was performed to assess scores of immune cells within INRs and IRs. The correlations between the diagnostic markers and differential immune cells were examined by conducting Spearman’s rank correlation analysis. Subsequently, miRNA-mRNA-TF interaction networks in accordance with the potential diagnostic markers were built with Cytoscape. We finally verified the mRNA expression of the diagnostic markers in clinical samples of INRs and IRs by performing RT-qPCR.

Results: We identified 52 DEGs in the samples of peripheral blood mononuclear cells (PBMC) between INRs and IRs. A few inflammatory and immune-related pathways, including chronic inflammatory response, T cell receptor signaling pathway, were enriched. FAM120AOS, LTA, FAM179B, JUN, PTMA, and SH3YL1 were considered as potential diagnostic markers. ssGSEA results showed that the IRs had significantly higher enrichment scores of seven immune cells compared with IRs. The miRNA-mRNA-TF network was constructed with 97 miRNAs, 6 diagnostic markers, and 26 TFs, which implied a possible regulatory relationship.

Conclusion: The six potential crucial genes, FAM120AOS, LTA, FAM179B, JUN, PTMA, and SH3YL1, may be associated with clinical diagnosis in INRs. Our study provided new insights into diagnostic and therapeutic targets.

Plasma MicroRNA Signature Panel Predicts the Immune Response After Antiretroviral Therapy in HIV-Infected Patients

Background

Approximately 10–40% of people with human immunodeficiency virus (HIV) infection are unable to obtain successful improvements in immune function after antiretroviral therapy (ART). These patients are at greater risk of developing non-acquired immunodeficiency syndrome (AIDS)-related conditions, with the accompanying increased morbidity and mortality. Discovering predictive biomarkers can help to identify patients with a poor immune response earlier and provide new insights into the mechanisms of this condition.

Methods

A total of 307 people with HIV were enrolled, including 110 immune non-responders (INRs) and 197 immune responders (IRs). Plasma samples were taken before ART, and quantities of plasma microRNAs (miRNAs) were determined using reverse transcriptase-quantitative polymerase chain reaction (RT-qPCR). Candidate biomarkers were established through four phases: discovery, training, validation, and blinded test. Binary logistic regression was used to analyze the combined predictive capacity of the identified miRNAs. The effect of one miRNA, miR-16-5p, on T cell function was assessed in vitro.

Results

Expression of five miRNAs (miR-580, miR-627, miR-138-5p, miR-16-5p, and miR-323-3p) was upregulated in the plasma of INRs compared with that in IRs. Expression of these miRNAs was negatively correlated with both CD4⁺ T cell counts and the increase in the proportion of CD4⁺ T cells after one year of ART. These five miRNAs were combined in a predictive model, which could effectively identify INRs or IRs. Furthermore, we found that miR-16-5p inhibits CD4⁺ T cell proliferation by regulating calcium flux.

Conclusion

We established a five-miRNA panel in plasma that accurately predicts poor immune response after ART, which could inform strategies to reduce the incidence of this phenomenon and improve the clinical management of these patients.

Clinical Safety Considerations of Integrase Strand Transfer Inhibitors in the Older Population Living with HIV

There are approximately 40 million people living with HIV globally, and 21% (7.9 million) are older adults (aged > 50 years) as of 2019. The average age of HIV-positive patients is predicted to increase to 58 by 2035. The favorable clinical efficacy of integrase strand transfer inhibitors has led to high rates of viral suppression and have now become the preferred agents by the AIDS guideline when initiating antiretroviral therapy. There are concerns of increasing adverse effects from HIV medications, such as integrase strand transfer inhibitors, as a result of changes in pharmacodynamic and pharmacokinetic parameters within the older population. The authors aim to describe the safety concerns of the current integrase strand transfer inhibitors based upon a narrative literature review, including recommendations for drug-drug interactions, and relevant comorbidities to consider for selection of the most appropriate integrase strand transfer inhibitor for older people living with HIV. Raltegravir is a well-tolerated option with minor adverse events; however, adherence to a twice-daily regimen may be difficult in older patients who are also taking many other medications for various comorbidities. Elvitegravir is also well tolerated with limited adverse effects, but has many drug-drug interactions that may pose problems for older patients with polypharmacy. Dolutegravir has been associated with more frequent adverse events, such as neuropsychiatric disorders.

Polymorphisms in TNF-α/TNFR1 pathway genes are associated with CD4+ T cells recovery in HIV-1-infected individuals on antiretroviral therapy

BACKGROUND

Antiretroviral therapy (ART) is an important hallmark of HIV-1 treatment, enabling viral load suppression to undetectable levels and CD4+ T cells recovery. However, some individuals do not recover the CD4+ T cell count to normal levels, despite viral suppression. We hypothesize that variation in genes involved in extrinsic apoptosis pathways may influence interindividual immune recovery during ART.

METHODS

We assessed clinic-epidemiological variables, and the allelic/genotypic distribution of functional single nucleotide polymorphisms in genes involved in extrinsic apoptosis pathways (TNFRSF1A: rs1800692, rs767455; TNFAIP3: rs2270926; NFKBIA: rs8904; TNF-α: rs1800629) and their relationship with immune recovery in ART treated (one year) HIV-1-infected individuals. We enrolled 155 HIV-1 infected individuals, 102 showing immunological success and 53 with immunological failure.

RESULTS

Through univariate analysis, we observed that the male sex (60.4%, p=0.002) showed higher median of age at treatment onset (34.8 years, p=0.034) and higher time until virological suppression (6 months, p=0.035), both risk factors for immune failure. Survival analysis revealed that individuals who started ART treatment with T CD4+ cells count <200 cells/mm3 took a longer time to immunological recovery (median time = 27 months, p=0.029). ART containing zidovudine (AZT) also was associated with immune recovery in univariate e multivariate analysis. Variants in TNFRSF1A (rs767455: T, TT; rs1800692-rs767455: T-T combination) and NFKBIA (rs8904: A) genes associated with immune failure, while NFKBIA (rs8904: GA) and TNF-α (rs1800629: GA), with CD4+ T cells recovery.

CONCLUSIONS

Clinic-epidemiological and variants in genes involved in extrinsic apoptosis pathways might influence the CD4+ T cells immune recovery.

Human umbilical cord mesenchymal stem cell transfusion in immune non-responders with AIDS: a multicenter randomized controlled trial

We examined the safety and efficacy of human umbilical cord mesenchymal stem cell (hUC-MSC) infusion for immune non-responder (INR) patients with chronic HIV-1 infection, who represent an unmet medical need even in the era of efficient antiretroviral therapy (ART). Seventy-two INR patients with HIV were enrolled in this phase II randomized, double-blinded, multicenter, placebo-controlled, dose-determination trial (NCT01213186) from May 2013 to March 2016. They were assigned to receive high-dose (1.5 × 10⁶/kg body weight) or low-dose (0.5 × 10⁶/kg body weight) hUC-MSC, or placebo. Their clinical and immunological parameters were monitored during the 96-week follow-up study. We found that hUC-MSC treatment was safe and well-tolerated. Compared with baseline, there was a statistical increase in CD4+ T counts in the high-dose (P < 0.001) and low-dose (P < 0.001) groups after 48-week treatment, but no change was observed in the control group. Kaplan–Meier analysis revealed a higher cumulative probability of achieving an immunological response in the low-dose group compared with the control group (95.8% vs. 70.8%, P = 0.004). However, no significant changes in CD4/CD8+ T counts and CD4/CD8 ratios were observed among the three groups. In summary, hUC-MSC treatment is safe. However, the therapeutic efficacy of hUC-MSC treatment to improve the immune reconstitution in INR patients still needs to be further investigated in a large cohort study.

Dynamics of HIV reservoir decay and naïve CD4 T-cell recovery between immune non-responders and complete responders on long-term antiretroviral treatment

BACKGROUND

The dynamics of viral reservoir decay and naïve CD4 T-cell recovery between immunological non-responders (INR) and complete responders (CR) during long-term antiretroviral treatment (ART) are not fully known.

METHODS

Twenty-eight chronic HIV-infected individuals on 5-year ART were divided into two groups: INR (CD4 counts ≤350 cells/μL, n = 13) and CR (CD4 counts ≥500 cells/μL, n = 15). The levels of HIV DNA and cell-associated HIV RNA (CA-RNA), CD4 counts, naïve CD4 counts and their correlations were analyzed at baseline, years 1, 3 and 5 of ART between the two groups. Expression of PD-1 on CD4 T-cells was quantified by flow cytometry. Linear mixed effect models were used to estimate the change procession in repeated measurements over 5 years. Slopes of the above-mentioned indicators were estimated using participant-specific linear regressions, respectively.

RESULTS

INR maintained higher levels of HIV DNA and CA-RNA with higher percentages of PD-1⁺CD4 T-cells compared with CR during 5-year ART, concurrent with lower naïve CD4 T-cells. However, the rates of HIV DNA and CA-RNA decay in INR were not different from that in CR over time, and INR had higher rates of naïve CD4 T-cell percentage recovery. The baseline levels of HIV DNA were positively associated with the 5-year levels of HIV DNA, but negatively associated with the 5-year naïve CD4 counts.

CONCLUSIONS

INR maintained significantly higher viral reservoir and lower naïve CD4 T-cells compared with CR during 5-year ART, however, the rates of reservoir decay and naïve CD4 T-cell percentage growth within INR were not lower than that in CR over time.

Determinants of suboptimal CD4+ T cell recovery after antiretroviral therapy initiation in a prospective cohort of acute HIV-1 infection

Introduction

Up to 30% of individuals treated with antiretroviral therapy (ART) during chronic HIV fail to recover CD4 counts to >500 cells/mm³ despite plasma viral suppression. We investigated the frequency and associations of suboptimal CD4 recovery after ART started during acute HIV infection (AHI).

Methods

Participants who started ART in Fiebig I to V AHI with ≥48 weeks of continuous documented HIV‐RNA < 50 copies/mL were stratified by CD4 count at latest study visit to suboptimal immune recovery (SIR; CD4 < 350 cells/mm³), intermediate immune recovery (IIR; 350 ≤ CD4 < 500) and complete immune recovery (CIR; CD4 ≥ 500). Clinical and laboratory parameters were assessed at pre‐ART baseline and latest study visit. Additional inflammatory and neurobehavioral endpoints were examined at baseline and 96 weeks.

Results

Of 304 participants (96% male, median 26 years old) evaluated after median 144 (range 60 to 420) weeks of ART initiated at median 19 days (range 1 to 62) post‐exposure, 3.6% (n = 11) had SIR and 14.5% (n = 44) had IIR. Pre‐ART CD4 count in SIR compared to CIR participants was 265 versus 411 cells/mm³ (p = 0.002). Individuals with SIR or IIR had a slower CD4 rate of recovery compared to those with CIR. Timing of ART initiation by Fiebig stage did not affect CD4 count during treatment. Following ART, the CD8⁺T cell count (p = 0.001) and CD4/CD8 ratio (p = 0.047) were lower in SIR compared to CIR participants. Compared to the CIR group at week 96, the combined SIR and IIR groups had higher sCD14 (p = 0.008) and lower IL‐6 (p = 0.04) in plasma, without differences in neuropsychological or psychiatric indices.

Conclusions

Despite immediate and sustained treatment in AHI, suboptimal CD4 recovery occurs uncommonly and is associated with low pre‐ART CD4 count as well as persistent low CD8 count and CD4/CD8 ratio during treatment.

Cell-Associated HIV-1 Unspliced-to-Multiply-Spliced RNA Ratio at 12 Weeks of ART Predicts Immune Reconstitution on Therapy

Human immunodeficiency virus (HIV) infection is currently managed by antiretroviral drugs, which block virus replication and promote immune restoration. However, the latter effect is not universal, with a proportion of infected individuals failing to sufficiently reconstitute their immune function despite a successful virological response to antiretroviral therapy (ART).

Incomplete restoration of CD4⁺ T-cell counts on antiretroviral therapy (ART) is a major predictor of HIV-related morbidity and mortality. To understand the possible mechanisms behind this poor immunological response despite viral suppression, we longitudinally measured more than 50 virological and immunological biomarkers in a cohort of HIV-infected individuals at several time points during the first 96 weeks of virologically suppressive ART. No baseline virological or immunological marker was predictive of the degree of immune reconstitution. However, the cell-associated HIV-1 unspliced-to-multiply-spliced (US/MS) RNA ratio at 12 weeks of ART positively correlated with markers of CD4⁺ T-cell activation and apoptosis and negatively predicted both the absolute and relative CD4⁺ T-cell counts at 48 and 96 weeks. A higher US/MS RNA ratio may reflect the higher frequency of productively infected cells that could exert pressure on the immune system, contributing to persistent immune activation and apoptosis and subsequently to a poor immunological response to ART.

Thymosin Alpha 1 Reduces the Mortality of Severe Coronavirus Disease 2019 by Restoration of Lymphocytopenia and Reversion of Exhausted T Cells

BACKGROUND

Thymosin alpha 1 (Tα1) had been used in the treatment of viral infections as an immune response modifier for many years. However, clinical benefits and the mechanism of Tα1 treatment for COVID-19 patients are still unclear.

METHODS

We retrospectively reviewed the clinical outcomes of 76 severe COVID-19 cases admitted to 2 hospitals in Wuhan, China, from December 2019 to March 2020. The thymus output in peripheral blood mononuclear cells from COVID-19 patients was measured by T-cell receptor excision circles (TRECs). The levels of T-cell exhaustion markers programmed death-1 (PD-1) and T-cell immunoglobulin and mucin domain protein 3 (Tim-3) on CD8+ T cells were detected by flow cytometry.

RESULTS

Compared with the untreated group, Tα1 treatment significantly reduced the mortality of severe COVID-19 patients (11.11% vs 30.00%, P = .044). Tα1 enhanced blood T-cell numbers in COVID-19 patients with severe lymphocytopenia. Under such conditions, Tα1 also successfully restored CD8+ and CD4+ T-cell numbers in elderly patients. Meanwhile, Tα1 reduced PD-1 and Tim-3 expression on CD8+ T cells from severe COVID-19 patients compared with untreated cases. It is of note that restoration of lymphocytopenia and acute exhaustion of T cells were roughly parallel to the rise of TRECs.

CONCLUSIONS

Tα1 treatment significantly reduced mortality of severe COVID-19 patients. COVID-19 patients with counts of CD8+ T cells or CD4+ T cells in circulation less than 400/μL or 650/μL, respectively, gained more benefits from Tα1. Tα1 reversed T-cell exhaustion and recovered immune reconstitution through promoting thymus output during severe acute respiratory syndrome-coronavirus 2 infection.

When the Damage Is Done: Injury and Repair in Thymus Function

Even though the thymus is exquisitely sensitive to acute insults like infection, shock, or common cancer therapies such as cytoreductive chemo- or radiation-therapy, it also has a remarkable capacity for repair. This phenomenon of endogenous thymic regeneration has been known for longer even than its primary function to generate T cells, however, the underlying mechanisms controlling the process have been largely unstudied. Although there is likely continual thymic involution and regeneration in response to stress and infection in otherwise healthy people, acute and profound thymic damage such as that caused by common cancer cytoreductive therapies or the conditioning regimes as part of hematopoietic cell transplantation (HCT), leads to prolonged T cell deficiency; precipitating high morbidity and mortality from opportunistic infections and may even facilitate cancer relapse. Furthermore, this capacity for regeneration declines with age as a function of thymic involution; which even at steady state leads to reduced capacity to respond to new pathogens, vaccines, and immunotherapy. Consequently, there is a real clinical need for strategies that can boost thymic function and enhance T cell immunity. One approach to the development of such therapies is to exploit the processes of endogenous thymic regeneration into novel pharmacologic strategies to boost T cell reconstitution in clinical settings of immune depletion such as HCT. In this review, we will highlight recent work that has revealed the mechanisms by which the thymus is capable of repairing itself and how this knowledge is being used to develop novel therapies to boost immune function.

Hypervitaminosis A is associated with immunological non-response in HIV-1-infected adults: a case-control study

For people living with HIV, determinants of immunological non-response (INR) to combined antiretroviral therapy (cART) have not been fully elucidated. In a case-control study, we evaluated the influence of the nutritional and antioxidant status in HIV-1 adults whose cART was initiated between January 2001 and December 2013. Cases had persistent CD4 counts < 350/μL vs. > 350/μL for controls, after at least 2 years of cART with persistent viral loads (VL) < 50 copies/mL. Twelve cases and twenty-eight control subjects with the same CD4 count at cART initiation were compared for their nutritional and antioxidant status after age adjustment at dosage assessment. Patients were predominantly male (70%), Caucasian (82%) and at AIDS stage (62%). The median age was 53, and the median CD4 count was 245/mm³ for cases and 630/mm³ for controls after a median time of 7 years on cART. Despite higher energy intakes in cases, anthropometric data was comparable between groups who had similar vitamins B9/B12/C/D/E, zinc, citrulline and glutamine levels. Nine cases (75%) and 8 controls (29%) had hypervitaminosis A (> 2.70 μmol/L) (p = 0.030). Cases had lower erythrocyte resistance when exposed to a controlled free radical attack (p = 0.014). Most cases had hypervitaminosis A and altered antioxidant capacities that could affect immunological response. Wide-scale studies are required, but in the meantime, screening of their vitamin A status must be encouraged in these patients.

Optimizing Treatment for Adults with HIV/AIDS in China: Successes over Two Decades and Remaining Challenges

Purpose of Review

The introduction of the National Free Antiretroviral Therapy Program (NFATP) in 2003 by the China National Center for AIDS/STD Control and Prevention has led to dramatic increases in antiretroviral therapy (ART) coverage among HIV-infected Chinese patients. Despite limitations in the number of available free antiretroviral drugs, the overall mortality associated with HIV/AIDS has dropped from 39.3 per 100 person-years in 2002 to 3.1 in 2014. In this review, we summarize the challenges, responses, and achievements of antiretroviral therapy (ART) in China over the past 20 years.

Recent Findings

Continuous optimization of the Chinese National Guidelines for HIV/AIDS Diagnosis and Treatment has been guided by data from serial domestic multi-center studies aimed at evaluating efficacy and toxicity of available ART regimens among Chinese patients with HIV, with the goal of maximizing adherence, access, and efficacy. In addition, increasing attention has been focused on the importance of continuity in the HIV care cascade to promote linkage to care, and address the multidisciplinary chronic care needs HIV/AIDS patients on lifelong ART.

Summary

Great progress has been achieved in the past 20 years in terms of access to and optimization of antiretroviral treatment in China. As the number of patients receiving long-term ART continues to grow, the focus of HIV/AIDS treatment has gradually transitioned from urgent care to the management of non-AIDS-related chronic complications and control of chronic inflammation.

Escalating and sustained immunovirological dissociation among antiretroviral drug-experienced perinatally human immunodeficiency virus-1-infected children and adolescents living in the Central African Republic: A STROBE-compliant study

Sub-Saharan Africa has the vast majority (∼90%) of new pediatric acquired immunodeficiency syndrome cases worldwide. Biologically monitoring HIV-infected pediatric populations remains challenging. The differential interest of human immunodeficiency virus (HIV)-1 RNA loads and CD4 T-cell counts is debated for the treatment of pediatric acquired immunodeficiency syndrome patients.Long-term antiretroviral treatment (ART) outcomes regarding immunological and virological surrogate markers were longitudinally evaluated between 2009 and 2014 (over 57 months) in 245 perinatally HIV-1-infected children and adolescents born from HIV-infected mothers, treated at inclusion for at least 6 months by the World Health Organization-recommended ART in Bangui, Central African Republic.Patients were monitored over time biologically for CD4 T-cell counts, HIV-1 RNA loads, and drug resistance mutation genotyping.Children lost to follow-up totaled 6%. Four categories of immunovirological responses to ART were observed. At baseline, therapeutic success with sustained immunological and virological responses was observed in 80 (32.6%) children; immunological and virologic nonresponses occurred in 32 (13.0%) children; finally, the majority (133; 54.2%) of the remaining children showed discordant immunovirological responses. Among them, 33 (13.4%) children showed rapid virological responses to ART with an undetectable viral load, whereas immunological responses remained absent after 6 months of treatment and increased progressively over time in most of the cases, suggesting slow immunorestoration. Notably, nearly half of the children (40.8% at baseline and 48.2% at follow-up) harbored discordant immunovirological responses with a paradoxically high CD4 T-cell count and HIV-1 RNA load, which are always associated with high levels of drug resistance mutations. The latter category showed a significant increase over time, with a growth rate of 1.23% per year of follow-up.Our STROBE-compliant study demonstrates the high heterogeneity of biological responses under ART in children with frequent passage from 1 category to another over time. Close biological evaluation with access to routine plasma HIV-1 RNA load monitoring is crucial for adapting the complex outcomes of ART in HIV-infected children born from infected mothers.

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.

CCR5 genotype and pre-treatment CD4+ T-cell count influence immunological recovery of HIV-positive patients during antiretroviral therapy

This study was performed to assess the association of CCR5Δ32 and SDF1-3'A polymorphisms with immunological recovery failure and to investigate the influence of sociodemographic and clinical data on immune reconstitution in human immunodeficiency virus (HIV)-positive patients during antiretroviral therapy (ART). Two hundred and forty-eight HIV-positive patients under ART with undetectable plasma viral load (<40 copies/mL) were enrolled in this study and classified into two groups according to their CD4+ T-cell count changes: immunological responders (CD4+ T-cell count gain ≥ 200/µL or ≥ 30% compared with baseline) and immunological non-responders (CD4+ T-cell count gain < 200/µL or < 30% compared with baseline). DNA extraction was performed followed by CCR5Δ32 and SDF1-3'A genotyping. Sociodemographic and clinical data were evaluated from medical records. The logistic regression model showed that heterozygosity for CCR5Δ32 allele and lower pre-treatment CD4+ T-cell count (<500 cells/µL) were statistically associated with immunological recovery failure (OR = 5.873, 95%CI = 1.204-28.633, P = 0.028 and OR = 10.00, 95%CI = 3.224-31.016, P = 0.028, respectively). No association of SDF1-3'A polymorphism with immune reconstitution failure was found. Additionally, we observed that there was a statistically significant difference between lower CD4+ T-cell count and INR status than the IR group (Z = 4.687, P < 0.001). Our results demonstrated, through a logistic regression model, that CCR5Δ32 polymorphism and pre-treatment CD4+ T-cell count have significant influence on immune reconstitution of HIV-positive patients during ART. These findings highlight some immunological factors associated with poor CD4+ T-lymphocytes recovery, which affect immune response level of ART-treated HIV-positive patients.

Incomplete immune reconstitution in HIV/AIDS patients on antiretroviral therapy: Challenges of immunological non-responders

The morbidity and mortality of HIV type-1 (HIV-1)-related diseases were dramatically diminished by the grounds of the introduction of potent antiretroviral therapy, which induces persistent suppression of HIV-1 replication and gradual recovery of CD4⁺ T-cell counts. However, ∼10-40% of HIV-1-infected individuals fail to achieve normalization of CD4⁺ T-cell counts despite persistent virological suppression. These patients are referred to as "inadequate immunological responders," "immunodiscordant responders," or "immunological non-responders (INRs)" who show severe immunological dysfunction. Indeed, INRs are at an increased risk of clinical progression to AIDS and non-AIDS events and present higher rates of mortality than HIV-1-infected individuals with adequate immune reconstitution. To date, the underlying mechanism of incomplete immune reconstitution in HIV-1-infected patients has not been fully elucidated. In light of this limitation, it is of substantial practical significance to deeply understand the mechanism of immune reconstitution and design effective individualized treatment strategies. Therefore, in this review, we aim to highlight the mechanism and risk factors of incomplete immune reconstitution and strategies to intervene.

Immunological recovery failure in cART-treated HIV-positive patients is associated with reduced thymic output and RTE CD4+ T cell death by pyroptosis

Despite more than three decades of studies and advances in combination antiretroviral therapy (cART) against human immunodeficiency virus (HIV), the mechanisms that precisely determine immune reconstitution failure have not been completely elucidated yet. Thus, this study aimed to investigate the thymic function, immune activation, and cell death by pyroptosis and apoptosis in virologically suppressed HIV-positive patients receiving cART. Immunophenotyping analyses were performed in 57 cART-treated HIV-infected patients with undetectable plasma viral load, who were classified as immunological nonresponders (INR = 29) and immunologic responders (IR = 28). Sociodemographic and clinical data were also assessed from medical records. Twelve healthy volunteers were also included in this study. The INR showed lower pretreatment CD4+ T cell count that remained low even after 1 yr of treatment, lower CD4/CD8 ratio, lower percentage of recent thymic emigrant (RTE) CD4+ T cell (CD45RA+CD31+) and naïve CD4+ T cell (CD45RA+CD62L+), higher levels of effector memory CD4+ T cells (CD45RA-CD62L-), and higher pyroptosis levels of RTE CD4+ T cells (CD31+FLICA-Caspase1+) when compared with IR. Our findings indicate that reduced thymic function and RTE CD4+ T cell death by pyroptosis are the major mechanisms of immunological recovery failure in HIV-infected patients receiving cART.

IL18 gene polymorphism and its influence on CD4+ T-cell recovery in HIV-positive patients receiving antiretroviral therapy

BACKGROUND

Pyroptosis has been reported to be critical in human immunodeficiency virus type 1 (HIV-1) pathogenesis and acquired immunodeficiency syndrome (AIDS) progression. Even after achieving viral suppression to undetectable levels during antiretroviral therapy (ART), exacerbated CD4+ T-cell death by pyroptosis has been suggested as one of the main causes of immunological non-response. Thus, variants in genes of pyroptosis pathway were studied in individuals with poor CD4+ T-cell reconstitution under antiretroviral therapy against HIV-1.

METHODS

248 virologically suppressed ART-treated patients, 126 immunological non-responders (INR) and 122 immunological responders (IR) were recruited. Genotyping was performed using TaqMan probe-based realtime PCR platform. Genotype-guided flow cytometry analysis with general and recent thymic emigrant (RTE) CD4+ T-cells in pyroptosis was performed based on associated polymorphisms.

RESULTS

Both IL18 rs187238 G allele and GG genotype were associated as protection factors against poor CD4+ T-cell recovery (OR = 0.22; 95%CI = 0.50-0.77; P = .010 and OR = 0.58; 95%CI = 0.36-0.93; P = .022, respectively). It was demonstrated a statistical association between IL18 rs187238 genotypes of ART-treated patients and death by Caspase-1 levels (P = .020). The GG genotype showed lower pyroptotic RTE CD4+ T-lymphocytes levels in the ART-treated groups comparing with CC (P = .029) and CG (P = .018) genotypes, suggesting that the G allele presence may be related to a lower IL-18 production and thus reduced dead CD4+ T-cells levels by Caspase-1.

CONCLUSION

We observed that IL18 G variant allele and genotype were associated with a better immunological response, which may influence on immunological recovery of HIV-positive patients receiving antiretroviral therapy, and low Caspase-1 activity levels was observed on GG genotype when compared CC genotypes.

Two types of poor immunological responder showing distinct responses to long-term HAART

OBJECTIVES

Most previous studies on poor immunological responders (PIRs) have been performed on one cohort at one time-point following highly active antiretroviral therapy (HAART). The aim of this study was to investigate whether there are different subtypes of PIR and whether a certain population might achieve better immune reconstitution following longer HAART.

METHODS

This study was designed as an ambispective cohort study, including a 4-5-year retrospective study and a 2-year prospective follow-up investigation. Thymic output, activated T cell and regulatory T cell (Treg) subset frequencies, expression levels of interferon-stimulated genes, and plasma concentrations of neopterin were determined at 4-5 years and 6-7 years following HAART initiation.

RESULTS

PIRs were subdivided into two populations after 4-5 years of HAART, according to the kinetics of T cell recovery. Type II PIRs exhibited a significantly lower percentage of naïve CD4⁺ T cells and CD31⁺ naïve CD4⁺ T cells compared with type I PIRs. After an additional 2 years of HAART treatment, type I PIRs showed a better outcome than type II PIRs. Furthermore, it was found that 2 years of additional HAART could persistently improve thymic output.

CONCLUSIONS

The two PIR subgroups are different in terms of immune characteristics and the response to prolonged HAART.

CD4 recovery is associated with genetic variation in IFNγ and IL19 genes

Not all HIV-infected patients receiving cART are able to recover optimal CD4-T cell levels despite achieving undetectable viremia. We evaluated the potential association between polymorphisms (SNPs) in cytokines involved in immune response (IL15, IFNγ and IL19) and the failure to achieve optimal CD4 T-cells restoration after cART. For this, we carried out a retrospective study in 412 HIV-infected patients starting cART with CD4<200 cells/μL. These patients were classified as immunological non-responders (INR) if having a CD4 increase (ΔCD4) below 200 cells/μL after two years on successful cART. IL15, IFNγ and IL19 polymorphisms were genotyped using Sequenom's MassARRAY platform. We found 134 INR patients with a median [IQR] ΔCD4 = 133[73-174] cells/μL. In the multivariate analysis adjusted for age, sex, infection route, ethnic origin, hepatitis co-infection and HIV infection length, the AA genotype of the SNP rs2430561 in IFNγ (OR:2.01[1.13-3.56], p = 0.017) and the TT genotype of polymorphism rs2243191 in IL19 (OR:2.58 [1.17-5.68], p = 0.019) showed significant association with the INR status. Our results show that polymorphisms in IFNγ and IL19 genes significantly impacts in the probability of not achieving an optimal immune recovery in HIV-patients starting cART with CD4 T-cells <200 cells/μL. Thus, these SNPs could represent potential predictive markers of the immunodiscordant response.

VDR polymorphisms influence immunological response in HIV-1+ individuals undergoing antiretroviral therapy

Vitamin D exerts an immuno-modulatory activity on several immune system cells through the vitamin D receptor (VDR). Herein, we verified that age and a therapeutic regimen containing protease inhibitors are associated with failures in antiretroviral therapies (ARVs). In addition, we assessed whether a VDR SNP (rs11568820: C allele and CC genotype) and GC (rs2228570-rs11568820) allelic combinations are associated with immunological failure (p < 0.05). Our findings suggest a possible role of VDR SNPs on immunological failure in HIV-1+ individuals undergoing regular ARVs.

IL7RA rs6897932 Polymorphism is Associated with Better CD4+ T-Cell Recovery in HIV Infected Patients Starting Combination Antiretroviral Therapy

Interleukin-7 receptor subunit alpha (IL7RA) rs6897932 polymorphism IS related to CD4⁺ recovery after combination antiretroviral therapy (cART), but no studies so far have analyzed its potential impact in patients with very low CD4⁺ T-cells count. We aimed to analyze the association between IL7RA rs6897932 polymorphism and CD4⁺ T-cells count restoration in HIV-infected patients starting combination antiretroviral therapy (cART) with CD4⁺ T-cells count <200 cells/mm³. We performed a retrospective study in 411 patients followed for 24 months with a DNA sample available for genotyping. The change in CD4⁺ T-cells count during the follow-up was considered as the primary outcome. The rs6897932 polymorphism had a minimum allele frequency (MAF) >20% and was in Hardy–Weinberg equilibrium (p = 0.550). Of 411 patients, 256 carried the CC genotype, while 155 had the CT/TT genotype. The CT/TT genotype was associated with a higher slope of CD4⁺ T-cells recovery (arithmetic mean ratio; AMR = 1.16; p = 0.016), higher CD4⁺ T-cells increase (AMR = 1.19; p = 0.004), and higher CD4⁺ T-cells count at the end of follow-up (AMR = 1.13; p = 0.006). Besides, rs6897932 CT/TT was related to a higher odds of having a value of CD4⁺ T-cells at the end of follow-up ≥500 CD4⁺ cells/mm³ (OR = 2.44; p = 0.006). After multiple testing correction (Benjamini–Hochberg), only the increase of ≥ 400 CD4⁺ cells/mm³ lost statistical significance (p = 0.052). IL7RA rs6897932 CT/TT genotype was related to a better CD4⁺ T-cells recovery and it could be used to improve the management of HIV-infected patients starting cART with CD4⁺ T-cells count <200 cells/mm³.

Genetic variation in CCR2 and CXCL12 genes impacts on CD4 restoration in patients initiating cART with advanced immunesupression

OBJECTIVE

We investigated the association of genetic polymorphisms in chemokine and chemokine receptor genes with poor immunological recovery in HIV patients starting combined antiretroviral therapy (cART) with low CD4 T-cell counts.

METHODS

A case-control study was conducted in 412 HIV-infected patients starting cART with CD4 T-cell count <200 cells/μL and successful viral control for two years. CD4 count increase below 200 cells/μL after two years on cART was used to define INR (immunological non-responder) patients. Polymorphisms in CXCL12, CCL5 and CCR2 genes were genotyped using sequenom's MassARRAY platform.

RESULTS

Thirty two percent (134/412) of patients were classified as INR. After adjusting by age, route of HIV infection, length of infection before cART and viral hepatitis coinfection, CCR2 rs1799864-AG genotype was significantly associated with INR status (OR [95% CI]: 1.80 [1.04-3.11]; p = 0.04), and CXCL12 rs1801157-TT genotype showed a trend (OR [95% CI]: 2.47 [0.96-6.35]; p = 0.06).

CONCLUSIONS

CCR2 rs1799864-AG or CXCL12 rs1801157-TT genotypes influence on the probability of poor CD4 recovery in the population of HIV patients starting cART with low CD4 counts. Genotyping of these polymorphisms could be used to estimate the risk of poor CD4 restoration, mainly in patients who are diagnosed late in the course of infection.

Thymic Function as a Predictor of Immune Recovery in Chronically HIV-Infected Patients Initiating Antiretroviral Therapy

Poor immunological responders (PIR) are HIV-infected patients with virologic suppression upon antiretroviral therapy (ART) but persistently low CD4⁺ T cell counts. Early identification of PIR is important given their higher morbimortality compared to adequate immune responders (AIR). In this study, 33 patients severely lymphopenic at ART onset, were followed for at least 36 months, and classified as PIR or AIR using cluster analysis grounded on their CD4⁺ T cell count trajectories. Based on a variety of immunological parameters, we built predictive models of PIR/AIR outcome using logistic regression. All PIR had CD4⁺ T cell counts consistently below 500 cells/μL, while all AIR reached this threshold. AIR showed a higher percentage of recent thymic emigrants among CD4⁺ T cells; higher numbers of sj-TRECs and greater sj/β TREC ratios; and significant increases in thymic volume from baseline to 12 months of ART. We identified mathematical models that correctly predicted PIR/AIR outcome after 36 months of therapy in 77-87% of the cases, based on observations made until 2-6 months after ART onset. This study highlights the importance of thymic activity in the immune recovery of severely lymphopenic patients, and may help to select the patients that will benefit from closer follow-up or novel therapeutic approaches.

Antiretroviral therapy immunologic non-response in a Brazilian population: association study using pharmaco- and immunogenetic markers

Background

Antiretroviral therapy (ART) saved millions from HIV-1 infection and AIDS, but some patients do not experience adequate CD4+ T cells gain despite achieving viral suppression. The genetic component of this condition is not yet completely elucidated.

Objective

To identify predictive genetic markers of immune response to ART.

Methods

Case–control study. Out of 176 HIV-infected patients recruited in the city of Recife, Northeast Brazil, 67 patients with no immunologic response were the cases and the remaining 109 patients who responded were the controls. A set of 94 selected single nucleotide polymorphisms (SNPs) involved in antiretroviral drugs pharmacodynamic pathways and immune system homeostasis were genotyped, while the remaining 48 were ancestry informative markers (AIMs) for controlling for eventual hidden population structure.

Results

Male patients were overrepresented in non-responder group (p = 0.01). Non-responders also started with lower absolute CD4+ T cell counts (p < 0.001). We found five SNPs significantly associated with the outcome, being three more frequent in non-responders than responders: rs2243250 (IL4) A allele (p = 0.04), rs1128503 (ABCB1) A allele (p = 0.03) and rs707265 (CYP2B6) A allele (p = 0.02), whereas the other two were less frequent in non-responders: rs2069762 (IL2) C allele (p = 0.004) and rs4646437 (CYP3A4) A allele (p = 0.04).

Conclusion

Some significant univariate associations remained independently associated at multivariate survival analysis modeling, such as pre-treatment CD4+ T cells counts, IL2 and ABCB1 genotypes, and use of protease inhibitors, yielding a predictive model for the probability for immune response. More studies are needed to unravel the genetic basis of ART immunological non-response.

Residual T cell activation and skewed CD8+ T cell memory differentiation despite antiretroviral therapy-induced HIV suppression

HIV infection results in excessive T cell activation and dysfunction which may persist even during effective antiretroviral therapy (ART). The dynamics of immune 'deactivation' and extent to which T cell memory subsets normalize after ART are unclear. We longitudinally assessed the influence of 1 year of ART on the phenotype of T cells in HIV-infected African women, relative to matched HIV-uninfected women, using activation (CD38, HLA-DR) and differentiation markers (CD27, CD45RO). ART induced a substantial reduction in T cell activation, but remained higher than HIV-uninfected controls. ART largely normalized the distribution of CD4+ T cell memory subsets, while the distribution of CD8+ T cell memory subsets remained significantly skewed compared to HIV-uninfected individuals. Thus, there was a considerable but only partial reversal of T cell defects upon ART. Understanding T cell impairment may provide important insights into mechanisms of HIV pathogenesis in the era of ART.

Thymic Function Failure Is Associated With Human Immunodeficiency Virus Disease Progression

Background

Thymic function has been mainly analyzed with surrogate peripheral markers affected by peripheral T-cell expansion, making it difficult to assess the role of thymic failure in human immunodeficiency virus (HIV) disease progression. The assay of signal-joint/DβJβ T-cell rearrangement excision circles (sj/β-TREC ratio) overcomes this limitation but has only been assayed in small cohorts. Thus, the aim of this study was to determine the role of thymic function, measured by the sj/β-TREC ratio, on CD4 T-cell maintenance in prospective HIV cohorts that include patients with a wide age range and different immunological phenotypes.

Methods

Seven hundred seventy-four patients including typical progressors, long-term nonprogressors (LTNPs), and vertically HIV-infected subjects were analyzed. Thymic function was quantified in peripheral blood samples using the sj/β-TREC ratio. Associations between thymic function and CD4 T-cell dynamics and combination antiretroviral therapy (cART) onset were analyzed using linear, logistic, and Cox proportional hazard models.

Results

Thymic function failure (sj/β-TREC ratio <10) was independently associated with HIV progression. In agreement, patients with distinctive high CD4 T-cell levels and low progression rates (vertically HIV-infected patients and LTNPs, including HIV controllers) had significantly higher thymic function levels whereas patients with thymic function failure had lower CD4 T-cell levels, lower nadir, and faster CD4 T-cell decay.

Conclusions

This work establishes the relevance of thymic function, measured by sj/β-TREC ratio, in HIV disease progression by analyzing a large number of patients in 3 cohorts with different HIV disease progression phenotypes. These results support and help to understand the mechanisms underlying the rationale of early cART onset.

The effects of prebiotics on microbial dysbiosis, butyrate production and immunity in HIV-infected subjects

Altered interactions between the gut mucosa and bacteria during HIV infection seem to contribute to chronic immune dysfunction. A deeper understanding of how nutritional interventions could ameliorate gut dysbiosis is needed. Forty-four subjects, including 12 HIV⁺ viremic untreated (VU) patients, 23 antiretroviral therapy-treated (ART⁺) virally suppressed patients (15 immunological responders and 8 non-responders) and 9 HIV^- controls (HIV^-), were blindly randomized to receive either prebiotics (scGOS/lcFOS/glutamine) or placebo (34/10) over 6 weeks in this pilot study. We assessed fecal microbiota composition using deep 16S rRNA gene sequencing and several immunological and genetic markers involved in HIV immunopathogenesis. The short dietary supplementation attenuated HIV-associated dysbiosis, which was most apparent in VU individuals but less so in ART⁺ subjects, whose gut microbiota was found more resilient. This compositional shift was not observed in the placebo arm. Significantly, declines in indirect markers of bacterial translocation and T-cell activation, improvement of thymic output, and changes in butyrate production were observed. Increases in the abundance of Faecalibacterium and Lachnospira strongly correlated with moderate but significant increases of butyrate production and amelioration of the inflammatory biomarkers soluble CD14 and high-sensitivity C-reactive protein, especially among VU. Hence, the bacterial butyrate synthesis pathway holds promise as a viable target for interventions.

Brief Report: A High Rate of β7+ Gut-Homing Lymphocytes in HIV-Infected Immunological Nonresponders is Associated With Poor CD4 T-Cell Recovery During Suppressive HAART

Supplemental Digital Content is Available in the Text.

Objective:

Correlation between GALT homing markers on lymphocytes and the low blood CD4 T-cell reconstitution in immunological nonresponders (INRs) has been studied.

Design:

Thirty-one INRs, 19 immunological responders (IRs), and 12 noninfected controls were enrolled in this study. INRs were defined by an undetectable plasma viral load RNA less than 40 copies per milliliter and CD4⁺ T-cell count <500 cells per cubic milliliter in at least 3 years.

Methods:

A complete peripheral and mucosal lymphocyte immunophenotyping was performed on these patients with a focus on the CCR9, CCR6, and α4β7 gut-homing markers.

Results:

A highly significant upregulation of α4β7 on INRs peripheral lymphocytes compared with that of IRs has been observed. This upregulation impacts different lymphocyte subsets namely CD4⁺, CD8⁺, and B lymphocytes. The frequency of β7⁺ Th17 and Treg cells are increased compared with IRs and healthy controls. The frequency of β7⁺ CD8⁺ T cells in the blood is negatively correlated with integrated proviral DNA in rectal lymphoid cells in contrast to β7⁺ CD4⁺ T cells associated with HIV integration.

Conclusions:

Alteration of lymphocyte homing abilities would have deleterious effects on GALT reconstitution and could participate to HIV reservoir constitution. These results emphasize the great interest to consider α4β7-targeted therapy in INR patients to block homing of lymphocytes and/or to directly impair gp120-α4β7 interactions.

Rapid CD4 decline prior to antiretroviral therapy predicts subsequent failure to reconstitute despite HIV viral suppression

HIV-1 infection is characterized by loss of CD4T cells, leading to immunodeficiency. Initiation of antiretroviral therapy (ART) results in suppression of the viral load and increased CD4 counts. Both viral and host factors determine CD4 cell responses to ART with approximately 15-30% of individuals having suboptimal increase of CD4T cell count, most commonly due to lack of compliance to ART. A smaller fraction of patients will have immune reconstitution failure and suboptimal CD4 increase despite suppression of HIV replication, and these individuals are at risk for adverse health outcomes. We sought to characterize the factors associated with decreased immunological response among Manitoba's HIV patient population. This retrospective case-control study included HIV patients with immune reconstitution failure despite suppression of HIV replication by ART. The immune reconstitution failure was defined by CD4 cell count increase from baseline of less than 100 CD4 cells/mm³ or lack of increase to above 200 CD4 cells/mm³ within one year of viral load suppression. Age and nadir CD4 cell counts are known risk factors associated with immune reconstitution failure. We chose controls (Patients with immune reconstitution success) of similar age and CD4 nadir cell with cases (Patients with immune reconstitution failure). We explored the potential effects of gender, HLA type, presence of co-infection, ethnicity, ART type, and rate of pre-treatment CD4 decline among cases and controls. Of more than 550 patients followed by our HIV clinic, 42 individuals met our definition of immune reconstitution failure and they were assigned to the cases group. 31 patients, comprising a range of ages and CD4 nadirs similar to those of the cases, were assigned to the control group. Our primary analysis was a regression model, predicting post-ART change in CD4 over time. After controlling for age and nadir CD4 cell counts, the only potential predictor that appears consistently associated with the rate of post-ART rise in CD4 over time in our cohort, regardless of the other variables that we have controlled for, is the rate of decline in CD4 pre-ART initiation. Several factors have been variably correlated with immune reconstitution failure of CD4 T cell count. Age and low CD4 nadir are factors previously shown to correlate with immune reconstitution failure; and we have controlled for them in our study. Another possible predictor is the rate of decline in CD4 pre-ART, which can serve as an additional marker of reconstitution failure and necessitate prioritizing individuals to ART initiation or identification of a subset of individuals that may be targeted for future adjunct strategies to improve immune recovery.

Reduced IL-7R T Cell Expression and Increased Plasma sCD127 in Late Presenting HIV-Infected Individuals

BACKGROUND

Late presentation of HIV infection is associated with reduced chance of optimal immune recovery after initiating combination antiretroviral therapy (cART). Interleukin-7 (IL-7) and the corresponding receptor, IL-7 receptor (IL-7R) made up of CD127 and CD132, are crucial for T cell homeostasis. This study aimed to describe IL-7R and IL-7 before and after initiation of cART in late presenting HIV-infected individuals, and the impact on immune recovery and T cell subset distribution after initiation of cART.

METHODS

A total of 100 HIV-infected individuals initiating cART were included in a prospective study. Samples were collected at baseline and after 6, 12, and 24 months of cART. Proportion and expression {[median fluorescence intensity (MFI)]} of IL-7R on T cells, and plasma concentrations of soluble CD127 (sCD127) and IL-7 were determined.

RESULTS

The IL-7R expression was reduced in late presenters with CD4 cell count <200 cells per microliter compared with nonlate presenters and healthy controls as demonstrated by lower proportion of CD127 + CD132 + T cells and lower CD127 MFI. In contrast, plasma sCD127 was higher. These differences were partly reversed after suppressive cART. Interestingly, the CD127 MFI on CD4 T cells was found to be a predictor of increased thymic output after 24 months of suppressive cART.

CONCLUSIONS

Severely altered IL-7R expression was found in late presenters, and associations between IL-7R expression and thymic output after 24 months of suppressive cART indicate an impact of a IL-7 response for the long term de novo production from thymus.

HIV sequence diversity during the early phase of infection is associated with HIV DNA reductions during antiretroviral therapy

The association between baseline human immunodeficiency virus (HIV) sequence diversity and HIV DNA decay after the initiation of antiretroviral therapy (ART) remains uncharacterized during the early stages of HIV infection. Samples were obtained from a cohort of 17 patients with early HIV infection (<6 months after infection) who initiated ART, and the C2V5 region of the HIV-1 envelope (env) gene was amplified via single genome amplification (SGA) to determine the peripheral plasma HIV quasispecies. We categorized HIV quasispecies into two groups according to baseline viral sequence genetic distance, which was determined by the Poisson-Fitter tool. Total HIV DNA in peripheral blood mononuclear cells (PBMCs), viral load, and T cell subsets were measured prior to and after the initiation of ART. The median SGA sequence number was 17 (range 6-28). At baseline, we identified 7 patients with homogeneous viral populations (designated the Homogeneous group) and 10 patients with heterogeneous viral populations (designated the Heterogeneous group) based on SGA sequences. Both groups exhibited similar HIV DNA decay rates during the first 6 months of ART (P > 0.99), but the Homogenous group experienced more prominent decay than the Heterogeneous group after 6 months (P = 0.037). The Heterogeneous group had higher CD4 cell counts after ART initiation; however, both groups had comparable recovery in terms of CD4/CD8 ratios and CD8 T cell activation levels. Viral population homogeneity upon the initiation of ART is associated with a decrease in HIV DNA levels during ART. J. Med. Virol. 89:982-988, 2017. © 2017 Wiley Periodicals, Inc.