Expression Profile and Biological Role of Immune Checkpoints in Disease Progression of HIV/SIV Infection

Immune checkpoint proteins are associated with persistently high liver stiffness after successful HCV treatment in people with HIV: a retrospective study

Various immune checkpoint proteins have been linked to cirrhosis. This study aimed to explore the association between plasma levels of these proteins measured one year after successful HCV treatment and persistently liver stiffness (defined as liver stiffness measurement (LSM) ≥ 12.5 kPa) five years after HCV treatment in people with HIV (PWH). We conducted a retrospective study involving 39 patients with HIV/HCV-coinfection who had advanced fibrosis or cirrhosis and achieved sustained virologic response (SVR). Plasma samples were obtained one year after treatment, and levels of immune checkpoints along with inflammatory biomarkers were evaluated using a Luminex 200TM analyzer. Statistical analyses were performed using Generalized Linear Models (GLMs) with a gamma distribution. Spearman correlation tests were used to analyze the correlation between significant immune checkpoints and inflammatory biomarkers. Although LSM values showed a decreasing trend over the years following successful HCV treatment, this trend was not statistically significant due to substantial variability among PWH. Persistently high liver stiffness was observed in 61.5% of patients five years after HCV treatment. Elevated plasma levels of soluble BTLA, PD-1, and TIM-3 one year after HCV treatment were associated with persistently liver stiffness five years later. These significant immune checkpoints were found to correlate with inflammatory biomarkers in PWH with persistently high liver stiffness. In conclusion, increased plasma concentrations of immune checkpoints one year after successful HCV therapy were linked to persistently high liver stiffness five years later, particularly BTLA, PD-1, and TIM-3. This suggests a potential immunopathological mechanism in ongoing liver stiffness post-HCV eradication.

Low plasma levels of BTLA and LAG-3 before HCV therapy are associated with metabolic disorders after HCV eradication in persons with HIV/HCV coinfection: a retrospective study

Background

Understanding the predictors of metabolic disorders in persons with HIV/HCV coinfection post-HCV therapy is crucial for improving patient outcomes. Since immune checkpoint proteins are usually upregulated in these persons with HIV/HCV coinfection, we aimed to evaluate the association between plasma immune checkpoint proteins at baseline (before HCV therapy) and metabolic disturbances during the follow-up (about 5 years after successful HCV treatment) in persons with HIV/HCV coinfection.

Methods

We performed a retrospective study on 80 persons with HIV/HCV coinfection with advanced fibrosis or cirrhosis who cleared HCV infection after successful HCV therapy and were followed for about 5 years after completion of HCV treatment. Plasma samples were collected at baseline. Immune checkpoint proteins were analyzed using a Luminex 200™ analyzer. Outcomes were the development of a metabolic event (type 2 diabetes mellitus and/or dyslipidemia) and the change in Triglycerides and glucose (TyG) index.

Results

During follow-up, 21 (26%) patients developed metabolic events (type 2 diabetes mellitus/dyslipidemia), and 29 (46.0%) patients had an increase in TyG during the follow-up. Low baseline values of BTLA and LAG-3, two immune checkpoint proteins, were associated with the development of metabolic events (aAMR = 0.69 and aAMR = 0.71, respectively) and with increases in TyG values (aAMR = 0.72 and aAMR = 0.70, respectively). In addition, other immune checkpoint proteins were also inversely associated with increases in TyG.

Conclusion

We discovered that low plasma levels of BTLA and LAG-3 before HCV therapy significantly correlate with an increased risk of developing metabolic disorders after treatment.

Vedolizumab and ART in recent HIV-1 infection unveil the role of α4β7 in reservoir size

BACKGROUNDWe evaluated the safety and viral rebound, after analytical treatment interruption (ATI), of vedolizumab and ART in recent HIV-1 infection. We used this model to analyze the effect of α4β7 on the HIV-1 reservoir size.METHODSParticipants started ART with monthly vedolizumab infusions, and ATI was performed at week 24. Biopsies were obtained from ileum and cecum at baseline and week 24. Vedolizumab levels, HIV-1 reservoir, flow cytometry, and cell-sorting and antibody competition experiments were assayed.RESULTSVedolizumab was safe and well tolerated. No participant achieved undetectable viremia off ART 24 weeks after ATI. Only a modest effect on the time to achieve more than 1,000 HIV-1 RNA copies/mL and the proportion of participants off ART was observed, being higher in the vedolizumab group compared with historical controls. Just before ATI, α4β7 expression was associated with HIV-1 DNA and RNA in peripheral blood and with PD1 and TIGIT levels. Importantly, a complete blocking of α4β7 was observed on peripheral CD4+ T cells but not in gut (ileum and cecum), where α4β7 blockade and vedolizumab levels were inversely associated with HIV-1 DNA.CONCLUSIONOur findings support α4β7 as an important determinant in HIV-1 reservoir size, suggesting the complete α4β7 blockade in tissue as a promising tool for HIV-cure combination strategies.TRIAL REGISTRATIONClinicalTrials.gov NCT03577782.FUNDINGThis work was supported by the Instituto de Salud Carlos III (Fondo Europeo de Desarrollo Regional, "a way to make Europe," research contracts FI17/00186 and FI19/00083 and research projects PI18/01532, PI19/01127, PI22/01796), Conserjería de Economía, Conocimiento, Empresas y Universidad, Junta de Andalucía (research projects P20/00906), the Red Temática de Investigación Cooperativa en SIDA (RD16/0025/0020), and the Spanish National Research Council.

Increased cAMP-PKA signaling pathway activation is involved in up-regulation of CTLA-4 expression in CD4+ T cells in acute SIVmac239-infected Chinese rhesus macaques

Human immunodeficiency virus-1 (HIV-1) infection can cause chronic activation, exhaustion, and anergy of the immune system. Cytotoxic T lymphocyte-associated antigen-4 (CTLA-4) is an immune checkpoint molecule, which plays an important role in immune homeostasis and disease. CTLA-4 expression is elevated in HIV-1-infected patients and is associated with disease progression. However, the mechanism controlling expression of CTLA-4 in HIV-1 infection is poorly characterized. In this study, we used a SIV-infected Chinese rhesus macaque (ChRM) model to explore CTLA-4 expression in SIV infection. Results showed that SIV infection significantly increased CTLA-4 expression in all T cell subsets, especially central memory T cells. CTLA-4+CD4+ T cell frequency was significantly associated with disease progression markers. Activation of the cyclic adenosine monophosphate (cAMP)-protein kinase A (PKA) signaling pathway regulated CTLA-4 expression in CD4+T cells, as confirmed by stimulation with dibutyryl cyclic adenosine monophosphate, forskolin, and 3-isobutyl-1-methylxanthine, and inhibition with H-89 ex vivo. Simultaneously, cAMP concentration in PBMCs and PKA activity in both PBMCs and CD4+ T cells were increased in acute SIV-infected ChRMs, accompanied by an increase in adenylate cyclase 6 expression and a decrease in cAMP-phosphodiesterase 3A (PDE3A), PDE4B, and PDE5A expression in PBMCs. In addition, selective inhibition of PDE4B and PDE5A activity enhanced CTLA-4 expression in CD4+ T cells. These results suggest that SIV infection alters cAMP metabolism and increases cAMP-PKA signaling pathway activation, which up-regulates the expression of CTLA-4 in acute SIVmac239-infected ChRMs. Thus, regulation of the cAMP-PKA signaling pathway may be a potential strategy for the restoration of T cell function and therapy for AIDS.

Identification and validation of PCSK9 as a prognostic and immune-related influencing factor in tumorigenesis: a pan-cancer analysis

Introduction

Proprotein convertase subtilisin/kexin-9 (PCSK9) has been primarily studied in the cardiovascular field however, its role in cancer pathophysiology remains incompletely defined. Recently, a pivotal role for PCSK9 in cancer immunotherapy was proposed based on the finding that PCSK9 inhibition was associated with enhancing the antigen presentation efficacy of target programmed cell death-1 (PD-1). Herein, we provide results of a comprehensive pan-cancer analysis of PCSK9 that assessed its prognostic and immunological functions in cancer.

Methods

Using a variety of available online cancer-related databases including TIMER, cBioPortal, and GEPIA, we identified the abnormal expression of PCSK9 and its potential clinical associations in diverse cancer types including liver, brain and lung. We also validated its role in progression-free survival (PFS) and immune infiltration in neuroblastoma.

Results

Overall, the pan-cancer survival analysis revealed an association between dysregulated PCSK9 and poor clinical outcomes in various cancer types. Specifically, PCSK9 was extensively genetically altered across most cancer types and was consistently found in different tumor types and substages when compared with adjacent normal tissues. Thus, aberrant DNA methylation may be responsible for PCSK9 expression in many cancer types. Focusing on liver hepatocellular carcinoma (LIHC), we found that PCSK9 expression correlated with clinicopathological characteristics following stratified prognostic analyses. PCSK9 expression was significantly associated with immune infiltrate since specific markers of CD8+ T cells, macrophage polarization, and exhausted T cells exhibited different PCSK9-related immune infiltration patterns in LIHC and lung squamous cell carcinoma. In addition, PCSK9 was connected with resistance of drugs such as erlotinib and docetaxel. Finally, we validated PCSK9 expression in clinical neuroblastoma samples and concluded that PCSK9 appeared to correlate with a poor PFS and natural killer cell infiltration in neuroblastoma patients.

Conclusion

PCSK9 could serve as a robust prognostic pan-cancer biomarker given its correlation with immune infiltrates in different cancer types, thus potentially highlighting a new direction for targeted clinical therapy of cancers.

Multi-dimensional characterization of immunological profiles in small cell lung cancer uncovers clinically relevant immune subtypes with distinct prognoses and therapeutic vulnerabilities

Small-cell lung cancer (SCLC) is generally considered a 'homogenous' disease, with little documented inter-tumor heterogeneity in treatment guidance or prognosis evaluation. The precise identification of clinically relevant molecular subtypes remains incomplete and their translation into clinical practice is limited. In this retrospective cohort study, we comprehensively characterized the immune microenvironment in SCLC by integrating transcriptional and protein profiling of formalin-fixation-and-paraffin-embedded (FFPE) samples from 29 patients. We identified two distinct disease subtypes: immune-enriched (IE-subtype) and immune-deprived (ID-subtype), displaying heterogeneity in immunological, biological, and clinical features. The IE-subtype was characterized by abundant immune infiltrate and elevated levels of interferon-alpha/gamma (IFNα/IFNγ) and inflammatory response, while the ID-subtype featured a complete lack of immune infiltration and a more proliferative phenotype. These two immune subtypes are associated with clinical benefits in SCLC patients treated with adjuvant therapy, with the IE-subtype exhibiting a more favorable response leading to improved survival and reduced disease recurrence risk. Additionally, we identified and validated a personalized prognosticator of immunophenotyping, the CCL5/CXCL9 chemokine index (CCI), using machine learning. The CCI demonstrated superior predictive abilities for prognosis and clinical benefits in SCLC patients, validated in our institute immunohistochemistry cohort and multicenter bulk transcriptomic data cohorts. In conclusion, our study provides a comprehensive and multi-dimensional characterization of the immune architecture of SCLC using clinical FFPE samples and proposes a new immune subtyping conceptual framework enabling risk stratification and the appropriate selection of individualized therapy.

Predictive plasma biomarkers of long-term increase in hepatic steatosis index after HCV eradication in HIV/HCV-coinfected patients

Hepatic steatosis is a common condition found in the liver of hepatitis C virus (HCV)-infected patients, contributing to more severe forms of liver disease. In addition, the human immunodeficiency virus (HIV) may accelerate this process. Alternatively, several immune checkpoint proteins have been reported to be upregulated and correlated with disease progression during HCV and HIV infections. In steatosis, a detrimental immune system activation has been established; however, the role of the immune checkpoints has not been addressed so far. Thus, this study aimed to evaluate the association between plasma immune checkpoint proteins at baseline (before antiviral therapy) with hepatic steatosis index (HSI) increase at the end of follow-up (∼ five years after sustained virologic response (SVR)). We performed a multicenter retrospective study in 62 patients coinfected with HIV/HCV who started antiviral therapy. Immune checkpoint proteins were analyzed at baseline using a Luminex 200TM analyzer. The statistical association analysis was carried out using Generalized Linear Models (GLM) and Partial Least Squares Discriminant Analysis (PLS-DA). Fifty-three percent of the patients showed HSI increase from baseline to the end of follow-up. Higher immune checkpoint protein levels of BTLA, CD137(4-1BB), CD80, GITR, LAG-3, and PD-L1 before HCV therapy were associated with a long-term increase in HSI after successful HCV therapy, suggesting a potential predictive role for early detection of progression towards steatosis in HIV/HCV-coinfected patients.

Toll-like receptor agonists enhance HIV-specific T cell response mediated by plasmacytoid dendritic cells in diverse HIV-1 disease progression phenotypes

BACKGROUND

Plasmacytoid dendritic cells (pDCs) sense viral and bacterial products through Toll-like receptor (TLR)-7 and -9 and translate this sensing into Interferon-α (IFN-α) production and T-cell activation. The understanding of the mechanisms involved in pDCs stimulation may contribute to HIV-cure immunotherapeutic strategies. The objective of the present study was to characterize the immunomodulatory effects of TLR agonist stimulations in several HIV-1 disease progression phenotypes and in non HIV-1 infected donors.

METHODS

pDCs, CD4 and CD8 T-cells were isolated from 450 ml of whole blood from non HIV-1 infected donors, immune responders (IR), immune non responders (INR), viremic (VIR) and elite controller (EC) participants. pDCs were stimulated overnight with AT-2, CpG-A, CpG-C and GS-9620 or no stimuli. After that, pDCs were co-cultured with autologous CD4 or CD8 T-cells and with/without HIV-1 (Gag peptide pool) or SEB (Staphylococcal Enterotoxin B). Cytokine array, gene expression and deep immunophenotyping were assayed.

FINDINGS

pDCs showed an increase of activation markers levels, interferon related genes, HIV-1 restriction factors and cytokines levels after TLR stimulation in the different HIV-disease progression phenotypes. This pDC activation was prominent with CpG-C and GS-9620 and induced an increase of HIV-specific T-cell response even in VIR and INR comparable with EC. This HIV-1 specific T-cell response was associated with the upregulation of HIV-1 restriction factors and IFN-α production by pDC.

INTERPRETATION

These results shed light on the mechanisms associated with TLR-specific pDCs stimulation associated with the induction of a T-cell mediated antiviral response which is essential for HIV-1 eradication strategies.

FUNDING

This work was supported by Gilead fellowship program, the Instituto de Salud Carlos III (Fondo Europeo de Desarrollo Regional, FEDER, "a way to make Europe") and the Red Temática de Investigación Cooperativa en SIDA and by the Spanish National Research Council (CSIC).

Programmed Cell Death Protein 1 Axis Inhibition in Viral Infections: Clinical Data and Therapeutic Opportunities

A vital function of the immune system is the modulation of an evolving immune response. It is responsible for guarding against a wide variety of pathogens as well as the establishment of memory responses to some future hostile encounters. Simultaneously, it maintains self-tolerance and minimizes collateral tissue damage at sites of inflammation. In recent years, the regulation of T-cell responses to foreign or self-protein antigens and maintenance of balance between T-cell subsets have been linked to a distinct class of cell surface and extracellular components, the immune checkpoint molecules. The fact that both cancer and viral infections exploit similar, if not the same, immune checkpoint molecules to escape the host immune response highlights the need to study the impact of immune checkpoint blockade on viral infections. More importantly, the process through which immune checkpoint blockade completely changed the way we approach cancer could be the key to decipher the potential role of immunotherapy in the therapeutic algorithm of viral infections. This review focuses on the effect of programmed cell death protein 1/programmed death-ligand 1 blockade on the outcome of viral infections in cancer patients as well as the potential benefit from the incorporation of immune checkpoint inhibitors (ICIs) in treatment of viral infections.

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.