Tumor-necrosis factor impairs CD4(+) T cell-mediated immunological control in chronic viral infection

Oxidative Stress in People Living With HIV: Are Diverse Supplement Sources the Solution?

Background and Aim

Antiretroviral therapy (ART) has reduced human immunodeficiency virus (HIV)/AIDS to a manageable chronic condition even though no cure exists. Despite ART control, latent HIV infection results in failed memory CD4 T-cell responses, immune overactivation, inflammation, oxidative stress, genomic instability, deoxyribonucleic acid (DNA) damage, and premature CD4 T-cell ageing. Overproduction of reactive oxygen species during oxidative stress can cause mitochondrial DNA damage, cancer, neurodegenerative and cardiovascular diseases, and premature aging in people living with HIV (PLWH). This review outlines current knowledge in oxidative stress among PLWH.

Methods

Google Scholar, Scopus, PubMed, and Science Direct were searched for literature conforming with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines from studies published from January 2013 to December 2023. A total of 75 studies from 22 countries were identified, with 52 studies carried out in human participants, 17 studies in cell lines, and 6 studies in animal models to assess oxidative stress levels.

Results

An increased oxidative stress with no changes in antioxidant levels was reported in HIV-positive smokers, and those on substance abuse. Long-term ART usage showed high levels of oxidative protein products and low levels of antioxidants when compared to short-term ART usage. The use of supplements such as N-acetylcysteine, selenium, and silibinin in animal models and cell lines showed increased cell viability, reduced reactive oxygen species, and increased antioxidant levels, which are promising therapeutic interventions that should be studied in PLWH to further help improve their disease outcomes.

Conclusions

Identifying extracts from natural and synthetic products with antioxidant effects will improve the general well-being of PLWH.

Tumour necrosis factor-alpha at the intersection of renal epithelial and immune cell function

This review explores the roles of tumour necrosis factor-alpha (TNF) in kidney physiology and pathology. TNF, produced by renal epithelial cells, regulates glucose, electrolyte, water and urea transport by modulating key transporters such as sodium-glucose co-transporter-2 (SGLT2), sodium-potassium-chloride cotransporter 2 (NKCC2), sodium chloride cotransporter (NCC), epithelial sodium channel (ENaC), aquaporin-2 (AQP2) and urea transporters. Under non-inflammatory conditions, TNF functions as a regulatory 'brake' on water and solute transport, particularly by attenuating NKCC2 and AQP2 activity. Disruption of these actions, coupled with increased salt intake, shifts mice from being salt-resistant to salt-sensitive, thereby altering their blood pressure. In autoimmune diseases, chronic kidney disease (CKD), hypertension with renal inflammation, and sepsis, TNF drives immune responses and disease progression. Although mechanisms underlying tubular epithelial cell (TEC)-immune cell interactions remain unclear, emerging evidence indicates that the spatial organization of immune responses in the kidney is associated with distinct TEC signature phenotypes. Hypertonicity- and NFAT5 (i.e. nuclear factor of activated T cells 5)-driven TNF production in TECs and T lymphocytes may influence immune cell communication by affecting co-stimulatory molecule expression and ENaC activity on macrophages and dendritic cells. Although TNF is generally pathogenic in renal diseases, its inhibition does not always confer protection because its effects on endoplasmic reticulum stress, ion transport, vascular smooth muscle and immune cells are influenced by distinct cellular sources and signalling mechanisms through TNF receptors 1 and 2. Anti-TNF therapies are crucial for treating chronic inflammatory diseases and may also aid in preventing the progression of acute kidney injury to CKD. A more complete understanding of the role of TNF in immunophysiological responses may enable the development of more targeted therapeutic strategies.

Inferring disease progression stages in single-cell transcriptomics using a weakly supervised deep learning approach

Application of single-cell/nucleus genomic sequencing to patient-derived tissues offers potential solutions to delineate disease mechanisms in humans. However, individual cells in patient-derived tissues are in different pathological stages, and hence, such cellular variability impedes subsequent differential gene expression analyses. To overcome such a heterogeneity issue, we present a novel deep learning approach, scIDST, that infers disease progression levels of individual cells with weak supervision framework. The disease progression-inferred cells display significant differential expression of disease-relevant genes, which cannot be detected by comparative analysis between patients and healthy donors. In addition, we demonstrate that pretrained models by scIDST are applicable to multiple independent data resources and are advantageous to infer cells related to certain disease risks and comorbidities. Taken together, scIDST offers a new strategy of single-cell sequencing analysis to identify bona fide disease-associated molecular features.

Dichotomous outcomes of TNFR1 and TNFR2 signaling in NK cell-mediated immune responses during inflammation

Natural killer (NK) cell function is regulated by a balance of activating and inhibitory signals. Tumor necrosis factor (TNF) is an inflammatory cytokine ubiquitous across homeostasis and disease, yet its role in regulation of NK cells remains unclear. Here, we find upregulation of the immune checkpoint protein, T cell immunoglobulin and mucin domain 3 (Tim3), is a biomarker of TNF signaling in NK cells during Salmonella Typhimurium infection. In mice with conditional deficiency of either TNF receptor 1 (TNFR1) or TNF receptor 2 (TNFR2) in NK cells, we find TNFR1 limits bacterial clearance whereas TNFR2 promotes it. Mechanistically, via single cell RNA sequencing we find that both TNFR1 and TNFR2 induce the upregulation of Tim3, while TNFR1 accelerates NK cell death but TNFR2 promotes NK cell accumulation and effector function. Our study thus highlights the complex interplay of TNF-based regulation of NK cells by the two TNF receptors during inflammation.

Prostaglandin E2-EP2/EP4 signaling induces immunosuppression in human cancer by impairing bioenergetics and ribosome biogenesis in immune cells

While prostaglandin E2 (PGE2) is produced in human tumor microenvironment (TME), its role therein remains poorly understood. Here, we examine this issue by comparative single-cell RNA sequencing of immune cells infiltrating human cancers and syngeneic tumors in female mice. PGE receptors EP4 and EP2 are expressed in lymphocytes and myeloid cells, and their expression is associated with the downregulation of oxidative phosphorylation (OXPHOS) and MYC targets, glycolysis and ribosomal proteins (RPs). Mechanistically, CD8+ T cells express EP4 and EP2 upon TCR activation, and PGE2 blocks IL-2-STAT5 signaling by downregulating Il2ra, which downregulates c-Myc and PGC-1 to decrease OXPHOS, glycolysis, and RPs, impairing migration, expansion, survival, and antitumor activity. Similarly, EP4 and EP2 are induced upon macrophage activation, and PGE2 downregulates c-Myc and OXPHOS in M1-like macrophages. These results suggest that PGE2-EP4/EP2 signaling impairs both adaptive and innate immunity in TME by hampering bioenergetics and ribosome biogenesis of tumor-infiltrating immune cells.

The multifaceted role of the stroma in the healthy prostate and prostate cancer

Prostate cancer (PC) is an age-related disease and represents, after lung cancer, the second cause of cancer death in males worldwide. Mortality is due to the metastatic disease, which mainly involves the bones, lungs, and liver. In the last 20 years, the incidence of metastatic PC has increased in Western Countries, and a further increase is expected in the near future, due to the population ageing. Current treatment options, including state of the art cancer immunotherapy, need to be more effective to achieve long-term disease control. The most significant anatomical barrier to overcome to improve the effectiveness of current and newly designed drug strategies consists of the prostatic stroma, in particular the fibroblasts and the extracellular matrix, which are the most abundant components of both the normal and tumor prostatic microenvironment. By weaving a complex communication network with the glandular epithelium, the immune cells, the microbiota, the endothelium, and the nerves, in the healthy prostatic microenvironment, the fibroblasts and the extracellular matrix support organ development and homeostasis. However, during inflammation, ageing and prostate tumorigenesis, they undergo dramatic phenotypic and genotypic changes, which impact on tumor growth and progression and on the development of therapy resistance. Here, we focus on the characteristics and functions of the prostate associated fibroblasts and of the extracellular matrix in health and cancer. We emphasize their roles in shaping tumor behavior and the feasibility of manipulating and/or targeting these stromal components to overcome the limitations of current treatments and to improve precision medicine's chances of success.

Immune system adaptation during gender-affirming testosterone treatment

Infectious, inflammatory and autoimmune conditions present differently in males and females. SARS-CoV-2 infection in naive males is associated with increased risk of death, whereas females are at increased risk of long COVID1, similar to observations in other infections2. Females respond more strongly to vaccines, and adverse reactions are more frequent3, like most autoimmune diseases4. Immunological sex differences stem from genetic, hormonal and behavioural factors5 but their relative importance is only partially understood6-8. In individuals assigned female sex at birth and undergoing gender-affirming testosterone therapy (trans men), hormone concentrations change markedly but the immunological consequences are poorly understood. Here we performed longitudinal systems-level analyses in 23 trans men and found that testosterone modulates a cross-regulated axis between type-I interferon and tumour necrosis factor. This is mediated by functional attenuation of type-I interferon responses in both plasmacytoid dendritic cells and monocytes. Conversely, testosterone potentiates monocyte responses leading to increased tumour necrosis factor, interleukin-6 and interleukin-15 production and downstream activation of nuclear factor kappa B-regulated genes and potentiation of interferon-γ responses, primarily in natural killer cells. These findings in trans men are corroborated by sex-divergent responses in public datasets and illustrate the dynamic regulation of human immunity by sex hormones, with implications for the health of individuals undergoing hormone therapy and our understanding of sex-divergent immune responses in cisgender individuals.

Single-cell RNA sequencing reveals the immunoregulatory roles of PegIFN-α in patients with chronic hepatitis B

BACKGROUND AND AIMS

Chronic hepatitis B (CHB) is caused by HBV infection and affects the lives of millions of people worldwide by causing liver inflammation, cirrhosis, and liver cancer. Interferon-alpha (IFN-α) therapy is a conventional immunotherapy that has been widely used in CHB treatment and achieved promising therapeutic outcomes by activating viral sensors and interferon-stimulated genes (ISGs) suppressed by HBV. However, the longitudinal landscape of immune cells of CHB patients and the effect of IFN-α on the immune system are not fully understood.

APPROACH AND RESULTS

Here, we applied single-cell RNA sequencing (scRNA-seq) to delineate the transcriptomic landscape of peripheral immune cells in CHB patients before and after PegIFN-α therapy. Notably, we identified three CHB-specific cell subsets, pro-inflammatory (Pro-infla) CD14+ monocytes, Pro-infla CD16+ monocytes and IFNG+ CX3CR1- NK cells, which highly expressed proinflammatory genes and positively correlated with HBsAg. Furthermore, PegIFN-α treatment attenuated percentages of hyperactivated monocytes, increased ratios of long-lived naive/memory T cells and enhanced effector T cell cytotoxicity. Finally, PegIFN-α treatment switched the transcriptional profiles of entire immune cells from TNF-driven to IFN-α-driven pattern and enhanced innate antiviral response, including virus sensing and antigen presentation.

CONCLUSIONS

Collectively, our study expands the understanding of the pathological characteristics of CHB and the immunoregulatory roles of PegIFN-α, which provides a new powerful reference for the clinical diagnosis and treatment of CHB.

TNF- α from the Proximal Nephron Exacerbates Aristolochic Acid Nephropathy

Key Points

Proximal tubular TNF aggravates kidney injury and fibrogenesis in aristolochic acid nephropathy. Tubular TNF disrupts the cell cycle in injured tubular epithelial cells. TNF-mediated toxic renal injury is independent of systemic immune responses.

Background

Aristolochic acid nephropathy (AAN) presents with tubular epithelial cell (TEC) damage and tubulointerstitial inflammation. Although TNF-α regulates cell apoptosis and inflammatory responses, the effects of tubular TNF in the progression of AAN require elucidation.

Methods

Floxed TNF mice on the 129/SvEv background were crossed with PEPCK-Cre mice to generate PEPCK-Cre + TNF flox/flox (TNF PTKO) mice or bred with Ksp-Cre mice to generate KSP-Cre + TNF flox/flox (TNF DNKO) mice. TNF PTKO, TNF DNKO, and wild-type controls (Cre negative littermates) were subjected to acute and chronic AAN.

Results

Deletion of TNF in the proximal but not distal nephron attenuated kidney injury, renal inflammation, and tubulointerstitial fibrosis after acute or chronic aristolochic acid (AA) exposure. The TNF PTKO mice did not have altered numbers of infiltrating myeloid cells in AAN kidneys. Nevertheless, kidneys from AA-treated TNF PTKO mice had reduced levels of proteins involved in regulated cell death, higher proportions of TECs in the G0/G1 phase, and reduced TEC proportions in the G2/M phase. Pifithrin-α , which restores the cell cycle, abrogated differences between the wild-type and PTKO cohorts in G2/M phase arrest of TECs and kidney fibrosis after AA exposure.

Conclusions

TNF from the proximal but not the distal nephron propagates kidney injury and fibrogenesis in AAN in part by inducing G2/M cell cycle arrest of TECs.

Identification of the novel FOXP3-dependent Treg cell transcription factor MEOX1 by high-dimensional analysis of human CD4+ T cells

CD4+ T cells play a central role in the adaptive immune response through their capacity to activate, support and control other immune cells. Although these cells have become the focus of intense research, a comprehensive understanding of the underlying regulatory networks that orchestrate CD4+ T cell function and activation is still incomplete. Here, we analyzed a large transcriptomic dataset consisting of 48 different human CD4+ T cell conditions. By performing reverse network engineering, we identified six common denominators of CD4+ T cell functionality (CREB1, E2F3, AHR, STAT1, NFAT5 and NFATC3). Moreover, we also analyzed condition-specific genes which led us to the identification of the transcription factor MEOX1 in Treg cells. Expression of MEOX1 was comparable to FOXP3 in Treg cells and can be upregulated by IL-2. Epigenetic analyses revealed a permissive epigenetic landscape for MEOX1 solely in Treg cells. Knockdown of MEOX1 in Treg cells revealed a profound impact on downstream gene expression programs and Treg cell suppressive capacity. These findings in the context of CD4+ T cells contribute to a better understanding of the transcriptional networks and biological mechanisms controlling CD4+ T cell functionality, which opens new avenues for future therapeutic strategies.

Development trends of immune activation during HIV infection in recent three decades: a bibliometric analysis based on CiteSpace

This study aimed to evaluate and pinpoint the status, hot areas, and frontiers of immune activation during HIV infection utilizing CiteSpace. From 1990 to 2022, we searched for studies on immune activation during HIV infection in the Web of Science Core Collection. CiteSpace was used to visually analyze the publications to identify the research status and pertinent research hotspots and frontiers in terms of the countries, institutions, authors, references, journals, and keywords. The Web of Science Core Collection yielded 5321 articles on immune activation during HIV infection. With 2854 and 364 articles, the United States and the University of California, San Francisco were the leading nation and institution in this domain. Steven G. Deeks has published 95 papers and is the most published author. The top cited articles on microbial translocation as a significant factor during HIV infection were published by Brenchley et al. Research on molecular/biology/genetics is often referenced in publications in the journals of molecular/biology/immunology. Inflammation, risk, mortality, cardiovascular disease, persistence, and biomarkers will be high-frequency words that are hot topics of research. According to the results, there was a strong collaboration between countries and organizations but little collaboration among authors. Molecular biology, immunology, and medicine are the main study subjects. The current hot topics in research are inflammation, risk, mortality, cardiovascular disease, persistence, and biomarkers. Future studies should concentrate on reducing the pathological changes caused by inflammation and altering the mechanisms of immune activation to reduce the size of the viral reservoir.

Interferon-induced IL-10 drives systemic T-cell dysfunction during chronic liver injury

BACKGROUND & AIMS

Patients with chronic liver disease (CLD), including cirrhosis, are at increased risk of intractable viral infections and are hyporesponsive to vaccination. Hallmarks of CLD and cirrhosis include microbial translocation and elevated levels of type I interferon (IFN-I). We aimed to investigate the relevance of microbiota-induced IFN-I in the impaired adaptive immune responses observed in CLD.

METHODS

We combined bile duct ligation (BDL) and carbon tetrachloride (CCl4) models of liver injury with vaccination or lymphocytic choriomeningitis virus infection in transgenic mice lacking IFN-I in myeloid cells (LysM-Cre IFNARflox/flox), IFNAR-induced IL-10 (MX1-Cre IL10flox/flox) or IL-10R in T cells (CD4-DN IL-10R). Key pathways were blocked in vivo with specific antibodies (anti-IFNAR and anti-IL10R). We assessed T-cell responses and antibody titers after HBV and SARS-CoV-2 vaccinations in patients with CLD and healthy individuals in a proof-of-concept clinical study.

RESULTS

We demonstrate that BDL- and CCL4-induced prolonged liver injury leads to impaired T-cell responses to vaccination and viral infection in mice, subsequently leading to persistent infection. We observed a similarly defective T-cell response to vaccination in patients with cirrhosis. Innate sensing of translocated gut microbiota induced IFN-I signaling in hepatic myeloid cells that triggered excessive IL-10 production upon viral infection. IL-10R signaling in antigen-specific T cells rendered them dysfunctional. Antibiotic treatment and inhibition of IFNAR or IL-10Ra restored antiviral immunity without detectable immune pathology in mice. Notably, IL-10Ra blockade restored the functional phenotype of T cells from vaccinated patients with cirrhosis.

CONCLUSION

Innate sensing of translocated microbiota induces IFN-/IL-10 expression, which drives the loss of systemic T-cell immunity during prolonged liver injury.

IMPACT AND IMPLICATIONS

Chronic liver injury and cirrhosis are associated with enhanced susceptibility to viral infections and vaccine hyporesponsiveness. Using different preclinical animal models and patient samples, we identified that impaired T-cell immunity in BDL- and CCL4-induced prolonged liver injury is driven by sequential events involving microbial translocation, IFN signaling leading to myeloid cell-induced IL-10 expression, and IL-10 signaling in antigen-specific T cells. Given the absence of immune pathology after interference with IL-10R, our study highlights a potential novel target to reconstitute T-cell immunity in patients with CLD that can be explored in future clinical studies.

Prioritizing exhausted T cell marker genes highlights immune subtypes in pan-cancer

Exhausted T (TEX) cells are main immunotherapy targets in cancer, but it lacks a general identification method to characterize TEX cell in disease. To assess the characterization of TEX cell, we extract signature of TEX cell from large cancer and chronic infection cohorts. Based on single-cell transcriptomes, a systematic T cell exhaustion prediction (TEXP) model is designed to define TEX cell in cancer and chronic infection. We then prioritize 42 marker genes, including HAVCR2, PDCD1, TOX, TIGIT and LAG3, which are associated with T cell exhaustion. TEXP could identify high TEX and low TEX subtypes in pan-cancer of TCGA. The high TEX subtypes are characterized by high immune score, immune cell infiltration, high expression of TEX marker genes and poor prognosis. In summary, TEXP and marker genes provide a resource for understanding the function of TEX cell, with implications for immune prediction and immunotherapy in chronic infection and cancer.

Pre-treatment levels of inflammatory markers and chemotherapy completion rates in patients with early-stage breast cancer

BACKGROUND

Chemotherapy efficacy is largely dependent on treatment adherence, defined by the relative dose intensity (RDI). Identification of new modifiable risk factors associated with low RDI might improve chemotherapy delivery. Here, we evaluated the association between low RDI and pre-chemotherapy factors, including patient- and treatment-related characteristics and markers of inflammation.

METHODS

This exploratory analysis assessed data from 267 patients with early-stage breast cancer scheduled to undergo (neo-)adjuvant chemotherapy included in the Physical training and Cancer (Phys-Can) trial. The association between low RDI, defined as < 85%, patient-related (age, body mass index, co-morbid condition, body surface area) and treatment-related factors (cancer stage, receptor status, chemotherapy duration, chemotherapy dose, granulocyte colony-stimulating factor) was investigated. Analyses further included the association between RDI and pre-chemotherapy levels of interleukin (IL)-6, IL-8, IL-10, C-reactive protein (CRP) and Tumor Necrosis Factor-alpha (TNF-α) in 172 patients with available blood samples.

RESULTS

An RDI of < 85% occurred in 31 patients (12%). Univariable analysis revealed a significant association with a chemotherapy duration above 20 weeks (p < 0.001), chemotherapy dose (p = 0.006), pre-chemotherapy IL-8 (OR 1.61; 95% CI (1.01; 2.58); p = 0.040) and TNF-α (OR 2.2 (1.17; 4.53); p = 0.019). In multivariable analyses, inflammatory cytokines were significant association with low RDI for IL-8 (OR: 1.65 [0.99; 2.69]; p = 0.044) and TNF-α (OR 2.95 [1.41; 7.19]; p = 0.007).

CONCLUSIONS

This exploratory analysis highlights the association of pre-chemotherapy IL-8 and TNF-α with low RDI of chemotherapy for breast cancer. IL-8 and TNF-α may therefore potentially help to identify patients at risk for experiencing dose reductions. Clinical trial number NCT02473003 (registration: June 16, 2015).

CD4+ T cells drive an inflammatory, TNF-α/IFN-rich tumor microenvironment responsive to chemotherapy

While chemotherapy remains the first-line treatment for many cancers, it is still unclear what distinguishes responders from non-responders. Here, we characterize the chemotherapy-responsive tumor microenvironment in mice, using RNA sequencing on tumors before and after cyclophosphamide, and compare the gene expression profiles of responders with progressors. Responsive tumors have an inflammatory and highly immune infiltrated pre-treatment tumor microenvironment characterized by the enrichment of pathways associated with CD4⁺ T cells, interferons (IFNs), and tumor necrosis factor alpha (TNF-α). The same gene expression profile is associated with response to cyclophosphamide-based chemotherapy in patients with breast cancer. Finally, we demonstrate that tumors can be sensitized to cyclophosphamide and 5-FU chemotherapy by pre-treatment with recombinant TNF-α, IFNγ, and poly(I:C). Thus, a CD4⁺ T cell-inflamed pre-treatment tumor microenvironment is necessary for response to chemotherapy, and this state can be therapeutically attained by targeted immunotherapy.

Heterogeneity of immune control in chronic hepatitis B virus infection: Clinical implications on immunity with interferon-α treatment and retreatment

Hepatitis B virus (HBV) infection is a global public health issue. Interferon-α (IFN-α) treatment has been used to treat hepatitis B for over 20 years, but fewer than 5% of Asians receiving IFN-α treatment achieve functional cure. Thus, IFN-α retreatment has been introduced to enhance antiviral function. In recent years, immune-related studies have found that the complex interactions between immune cells and cytokines could modulate immune response networks, in-cluding both innate and adaptive immunity, triggering immune responses that control HBV replication. However, heterogeneity of the immune system to control HBV infection, particularly HBV-specific CD8⁺ T cell heterogeneity, has consequ-ential effects on T cell-based immunotherapy for treating HBV infection. Altogether, the host’s genetic variants, negative-feedback regulators and HBV components affecting the immune system's ability to control HBV. In this study, we reviewed the literature on potential immune mechanisms affecting the immune control of HBV and the clinical effects of IFN-α treatment and retreatment.

Breast cancer microenvironment and obesity: challenges for therapy

Women with obesity who develop breast cancer have a worsened prognosis with diminished survival rates and increased rates of metastasis. Obesity is also associated with decreased breast cancer response to endocrine and chemotherapeutic treatments. Studies utilizing multiple in vivo models of obesity as well as human breast tumors have enhanced our understanding of how obesity alters the breast tumor microenvironment. Changes in the complement and function of adipocytes, adipose-derived stromal cells, immune cells, and endothelial cells and remodeling of the extracellular matrix all contribute to the rapid growth of breast tumors in the context of obesity. Interactions of these cells enhance secretion of cytokines and adipokines as well as local levels of estrogen within the breast tumor microenvironment that promote resistance to multiple therapies. In this review, we will discuss our current understanding of the impact of obesity on the breast tumor microenvironment, how obesity-induced changes in cellular interactions promote resistance to breast cancer treatments, and areas for development of treatment interventions for breast cancer patients with obesity.

Adaptive immune defense prevents Bartonella persistence upon trans-placental transmission

Vertical transmission of Bartonella infection has been reported for several mammalian species including mice and humans. Accordingly, it is commonly held that acquired immunological tolerance contributes critically to the high prevalence of Bartonellae in wild-ranging rodent populations. Here we studied an experimental model of Bartonella infection in mice to assess the impact of maternal and newborn immune defense on vertical transmission and bacterial persistence in the offspring, respectively. Congenital infection was frequently observed in B cell-deficient mothers but not in immunocompetent dams, which correlated with a rapid onset of an antibacterial antibody response in infected WT animals. Intriguingly, B cell-deficient offspring with congenital infection exhibited long-term bacteremia whereas B cell-sufficient offspring cleared bacteremia within a few weeks after birth. Clearance of congenital Bartonella infection resulted in immunity against bacterial rechallenge, with the animals mounting Bartonella-neutralizing antibody responses of normal magnitude. These observations reveal a key role for humoral immune defense by the mother and offspring in preventing and eliminating vertical transmission. Moreover, congenital Bartonella infection does not induce humoral immune tolerance but results in anti-bacterial immunity, questioning the contribution of neonatal tolerance to Bartonella prevalence in wild-ranging rodents.

Single-Cell Multiomics Reveals Clonal T-Cell Expansions and Exhaustion in Blastic Plasmacytoid Dendritic Cell Neoplasm

The immune system represents a major barrier to cancer progression, driving the evolution of immunoregulatory interactions between malignant cells and T-cells in the tumor environment. Blastic plasmacytoid dendritic cell neoplasm (BPDCN), a rare acute leukemia with plasmacytoid dendritic cell (pDC) differentiation, provides a unique opportunity to study these interactions. pDCs are key producers of interferon alpha (IFNA) that play an important role in T-cell activation at the interface between the innate and adaptive immune system. To assess how uncontrolled proliferation of malignant BPDCN cells affects the tumor environment, we catalog immune cell heterogeneity in the bone marrow (BM) of five healthy controls and five BPDCN patients by analyzing 52,803 single-cell transcriptomes, including 18,779 T-cells. We test computational techniques for robust cell type classification and find that T-cells in BPDCN patients consistently upregulate interferon alpha (IFNA) response and downregulate tumor necrosis factor alpha (TNFA) pathways. Integrating transcriptional data with T-cell receptor sequencing via shared barcodes reveals significant T-cell exhaustion in BPDCN that is positively correlated with T-cell clonotype expansion. By highlighting new mechanisms of T-cell exhaustion and immune evasion in BPDCN, our results demonstrate the value of single-cell multiomics to understand immune cell interactions in the tumor environment.

TNF in the liver: targeting a central player in inflammation

Tumour necrosis factor-α (TNF) is a multifunctional cytokine. First recognized as an endogenous soluble factor that induces necrosis of solid tumours, TNF became increasingly important as pro-inflammatory cytokine being involved in the immunopathogenesis of several autoimmune diseases. In the liver, TNF induces numerous biological responses such as hepatocyte apoptosis and necroptosis, liver inflammation and regeneration, and autoimmunity, but also progression to hepatocellular carcinoma. Considering these multiple functions of TNF in the liver, we propose anti-TNF therapies that specifically target TNF signalling at the level of its specific receptors.

Single-cell transcriptomic landscape identifies the expansion of peripheral blood monocytes as an indicator of HIV-1-TB co-infection

Certain circulating cell subsets are involved in immune dysregulation in human immunodeficiency virus type 1 (HIV-1) and tuberculosis (TB) co-infection; however, the characteristics and role of these subclusters are unknown. Peripheral blood mononuclear cells (PBMCs) of patients with HIV-1 infection alone (HIV-pre) and those with HIV-1-TB co-infection without anti-TB treatment (HIV-pre & TB-pre) and with anti-TB treatment for 2 weeks (HIV-pre & TB-pos) were subjected to single-cell RNA sequencing (scRNA-seq) to characterize the transcriptome of different immune cell subclusters. We obtained > 60,000 cells and identified 32 cell subclusters based on gene expression. The proportion of immune-cell subclusters was altered in HIV-1-TB co-infected individuals compared with that in HIV-pre-group, indicating immune dysregulation corresponding to different disease states. The proportion of an inflammatory CD14+CD16+ monocyte subset was higher in the HIV-pre & TB-pre group than in the HIV-pre group; this was validated in an additional cohort (n = 80) via a blood cell differential test, which also demonstrated a good discriminative performance (area under the curve, 0.8046). These findings depicted the atlas of immune PBMC subclusters in HIV-1-TB co-infection and demonstrate that monocyte subsets in peripheral blood might serve as a discriminating biomarker for diagnosis of HIV-1-TB co-infection.

Improving Therapeutic Vaccination against Hepatitis B-Insights from Preclinical Models of Immune Therapy against Persistent Hepatitis B Virus Infection

Chronic hepatitis B affects more than 250 million individuals worldwide, putting them at risk of developing liver cirrhosis and liver cancer. While antiviral immune responses are key to eliminating hepatitis B virus (HBV) infections, insufficient antiviral immunity characterized by failure to eliminate HBV-infected hepatocytes is associated with chronic hepatitis B. Prophylactic vaccination against hepatitis B successfully established protective immunity against infection with the hepatitis B virus and has been instrumental in controlling hepatitis B. However, prophylactic vaccination schemes have not been successful in mounting protective immunity to eliminate HBV infections in patients with chronic hepatitis B. Here, we discuss the current knowledge on the development and efficacy of therapeutic vaccination strategies against chronic hepatitis B with particular emphasis on the pathogenetic understanding of dysfunctional anti-viral immunity. We explore the development of additional immune stimulation measures within tissues, in particular activation of immunogenic myeloid cell populations, and their use for combination with therapeutic vaccination strategies to improve the efficacy of therapeutic vaccination against chronic hepatitis B.

CD4 T-Cell Exhaustion: Does It Exist and What Are Its Roles in Cancer?

In chronic infections and in cancer, persistent antigen stimulation under suboptimal conditions can lead to the induction of T-cell exhaustion. Exhausted T cells are characterized by an increased expression of inhibitory markers and a progressive and hierarchical loss of function. Although cancer-induced exhaustion in CD8 T cells has been well-characterized and identified as a therapeutic target (i.e., via checkpoint inhibition), in-depth analyses of exhaustion in other immune cell types, including CD4 T cells, is wanting. While perhaps attributable to the contextual discovery of exhaustion amidst chronic viral infection, the lack of thorough inquiry into CD4 T-cell exhaustion is particularly surprising given their important role in orchestrating immune responses through T-helper and direct cytotoxic functions. Current work suggests that CD4 T-cell exhaustion may indeed be prevalent, and as CD4 T cells have been implicated in various disease pathologies, such exhaustion is likely to be clinically relevant. Defining phenotypic exhaustion in the various CD4 T-cell subsets and how it influences immune responses and disease severity will be crucial to understanding collective immune dysfunction in a variety of pathologies. In this review, we will discuss mechanistic and clinical evidence for CD4 T-cell exhaustion in cancer. Further insight into the derivation and manifestation of exhaustive processes in CD4 T cells could reveal novel therapeutic targets to abrogate CD4 T-cell exhaustion in cancer and induce a robust antitumor immune response.

The role of ADAM17 during liver damage

A disintegrin and metalloprotease (ADAM) 17 is a membrane bound protease, involved in the cleavage and thus regulation of various membrane proteins, which are critical during liver injury. Among ADAM17 substrates are tumor necrosis factor α (TNFα), tumor necrosis factor receptor 1 and 2 (TNFR1, TNFR2), the epidermal growth factor receptor (EGFR) ligands amphiregulin (AR) and heparin-binding-EGF-like growth factor (HB-EGF), the interleukin-6 receptor (IL-6R) and the receptor for a hepatocyte growth factor (HGF), c-Met. TNFα and its binding receptors can promote liver injury by inducing apoptosis and necroptosis in liver cells. Consistently, hepatocyte specific deletion of ADAM17 resulted in increased liver cell damage following CD95 stimulation. IL-6 trans-signaling is critical for liver regeneration and can alleviate liver damage. EGFR ligands can prevent liver damage and deletion of amphiregulin and HB-EGF can result in increased hepatocyte death and reduced proliferation. All of which indicates that ADAM17 has a central role in liver injury and recovery from it. Furthermore, inactive rhomboid proteins (iRhom) are involved in the trafficking and maturation of ADAM17 and have been linked to liver damage. Taken together, ADAM17 can contribute in a complex way to liver damage and injury.

Insights into the biology and therapeutic implications of TNF and regulatory T cells

Treatments that block tumour necrosis factor (TNF) have major beneficial effects in several autoimmune and rheumatic diseases, including rheumatoid arthritis. However, some patients do not respond to TNF inhibitor treatment and rare occurrences of paradoxical disease exacerbation have been reported. These limitations on the clinical efficacy of TNF inhibitors can be explained by the differences between TNF receptor 1 (TNFR1) and TNFR2 signalling and by the diverse effects of TNF on multiple immune cells, including FOXP3⁺ regulatory T cells. This basic knowledge sheds light on the consequences of TNF inhibitor therapies on regulatory T cells in treated patients and on the limitations of such treatment in the control of diseases with an autoimmune component. Accordingly, the next generation of drugs targeting TNF is likely to be based on agents that selectively block the binding of TNF to TNFR1 and on TNFR2 agonists. These approaches could improve the treatment of rheumatic diseases in the future.

Checkpoint blockade accelerates a novel switch from an NKT-driven TNFα response toward a T cell driven IFN-γ response within the tumor microenvironment

Background

The temporal response to checkpoint blockade (CB) is incompletely understood. Here, we profiled the tumor infiltrating lymphocyte (TIL) landscape in response to combination checkpoint blockade at two distinct timepoints of solid tumor growth.

Methods

C57BL/6 mice bearing subcutaneous MC38 tumors were treated with anti-PD-1 and/or anti-CTLA-4 antibodies. At 11 or 21 days, TIL phenotype and effector function were analyzed in excised tumor digests using high parameter flow cytometry. The contributions of major TIL populations toward overall response were then assessed using ex vivo cytotoxicity and in vivo tumor growth assays.

Results

The distribution and effector function among 37 distinct TIL populations shifted dramatically between early and late MC38 growth. At 11 days, the immune response was dominated by Tumor necrosis factor alpha (TNFα)-producing NKT, representing over half of all TIL. These were accompanied by modest frequencies of natural killer (NK), CD4⁺, or CD8⁺ T cells, producing low levels of IFN-γ. At 21 days, NKT populations were reduced to a combined 20% of TIL, giving way to increased NK, CD4⁺, and CD8⁺ T cells, with increased IFN-γ production. Treatment with CB accelerated this switch. At day 11, CB reduced NKT to less than 20% of all TIL, downregulated TNFα across NKT and CD4⁺ T cell populations, increased CD4⁺ and CD8⁺ TIL frequencies, and significantly upregulated IFN-γ production. Degranulation was largely associated with NK and NKT TIL. Blockade of H-2kb and/or CD1d during ex vivo cytotoxicity assays revealed NKT has limited direct cytotoxicity against parent MC38. However, forced CD1d overexpression in MC38 cells significantly diminished tumor growth, suggesting NKT TIL exerts indirect control over MC38 growth.

Conclusions

Despite an indirect benefit of early NKT activity, CB accelerates a switch from TNFα, NKT-driven immune response toward an IFN-γ driven CD4⁺/CD8⁺ T cell response in MC38 tumors. These results uncover a novel NKT/T cell switch that may be a key feature of CB response in CD1d⁺ tumors.

The Genome-wide Methylation Profile of CD4+ T Cells From Individuals With Human Immunodeficiency Virus (HIV) Identifies Distinct Patterns Associated With Disease Progression

BACKGROUND

Human genetic variation-mostly in the human leukocyte antigen (HLA) and C-C chemokine receptor type 5 (CCR5) regions-explains 25% of the variability in progression of human immunodeficiency virus (HIV) infection. However, it is also known that viral infections can modify cellular DNA methylation patterns. Therefore, changes in the methylation of cytosine-guanine (CpG) islands might modulate progression of HIV infection.

METHODS

In total, 85 samples were analyzed: 21 elite controllers (EC), 21 subjects with HIV before combination antiretroviral therapy (cART) (viremic, 93 325 human immunodeficiency virus type 1 [HIV-1] RNA copies/mL) and under suppressive cART (cART, median of 17 months, <50 HIV-1 RNA copies/mL), and 22 HIV-negative donors (HIVneg). We analyzed the methylation pattern of 485 577 CpG in DNA from peripheral CD4+ T lymphocytes. We selected the most differentially methylated gene (TNF) and analyzed its specific methylation, messenger RNA (mRNA) expression, and plasma protein levels in 5 individuals before and after initiation of cART.

RESULTS

We observed 129 methylated CpG sites (associated with 43 gene promoters) for which statistically significant differences were recorded in viremic versus HIVneg, 162 CpG sites (55 gene promoters) in viremic versus cART, 441 CpG sites (163 gene promoters) in viremic versus EC, but none in EC versus HIVneg. The TNF promoter region was hypermethylated in viremic versus HIVneg, cART, and EC. Moreover, we observed greater plasma levels of TNF in viremic individuals than in EC, cART, and HIVneg.

CONCLUSIONS

Our study shows that genome methylation patterns vary depending on HIV infection status and progression profile and that these variations might have an impact on controlling HIV infection in the absence of cART.

Liver fibrosis promotes immune escape in hepatocellular carcinoma via GOLM1-mediated PD-L1 upregulation

Immune checkpoint blockade is considered a breakthrough in cancer treatment. However, with the low response rates and therapeutic resistance of patients with hepatocellular carcinoma (HCC), the challenges facing the application of this treatment are tremendous. Liver fibrosis is a key driver of tumor immune escape, the underlying mechanism has never been clarified. This study sought to explore the role of liver fibrosis in regulating tumor-infiltrating lymphocytes (TILs) and inducing tumor immunosuppression. Ninety-nine fixed HCC tissue samples were used to analyze the association between liver fibrosis and immune escape using immunohistochemistry. In HCC patients, low FIB-4 values and high CD8⁺ T cell infiltration were correlated with prolonged survival. Elevated expression of immune checkpoints and attenuated antitumor immunity were observed in CCl₄-induced mice liver fibrosis models and human fibrotic livers compared to control group. GOLM1 levels were increased in livers of patients with fibrosis and mice in response to CCl₄-induced liver fibrosis. CD8⁺ T cell infiltrations were significantly decreased and PD-L1 expression was significantly increased in tumor tissues from hepatocyte-specific GOLM1 transgenic mice (Alb/GOLM1 mice) inducing chemical carcinogenesis compared to their corresponding control WT mice. GOLM1 induced PD-L1 expression via EGFR pathway activation. EGFR inhibitors, especially together with anti-PD-L1 therapy, improved the efficacy of immunotherapy in HCC. These findings illustrate the importance of liver fibrosis-induced immunosuppression as a tumor-promoting mechanism. GOLM1, which is highly upregulated in the fibrotic liver, regulates tumor microenvironmental immune escape via the EGFR/PD-L1 signaling pathway. EGFR blockade may bolster the efficacy of immune checkpoint inhibitors for HCC treatment.

CD40 Agonist Overcomes T Cell Exhaustion Induced by Chronic Myeloid Cell IL-27 Production in a Pancreatic Cancer Preclinical Model

Pancreatic cancer is a particularly lethal malignancy that resists immunotherapy. In this study, using a preclinical pancreatic cancer murine model, we demonstrate a progressive decrease in IFN-γ and granzyme B and a concomitant increase in Tox and IL-10 in intratumoral tumor-specific T cells. Intratumoral myeloid cells produced elevated IL-27, a cytokine that correlates with poor patient outcome. Abrogating IL-27 signaling significantly decreased intratumoral Tox⁺ T cells and delayed tumor growth yet was not curative. Agonistic αCD40 decreased intratumoral IL-27-producing myeloid cells, decreased IL-10-producing intratumoral T cells, and promoted intratumoral Klrg1⁺Gzmb⁺ short-lived effector T cells. Combination agonistic αCD40+αPD-L1 cured 63% of tumor-bearing animals, promoted rejection following tumor rechallenge, and correlated with a 2-log increase in pancreas-residing tumor-specific T cells. Interfering with Ifngr1 expression in nontumor/host cells abrogated agonistic αCD40+αPD-L1 efficacy. In contrast, interfering with nontumor/host cell Tnfrsf1a led to cure in 100% of animals following agonistic αCD40+αPD-L1 and promoted the formation of circulating central memory T cells rather than long-lived effector T cells. In summary, we identify a mechanistic basis for T cell exhaustion in pancreatic cancer and a feasible clinical strategy to overcome it.

Differential inflammasome activation predisposes to acute-on-chronic liver failure in human and experimental cirrhosis with and without previous decompensation

OBJECTIVE

Systemic inflammation predisposes acutely decompensated (AD) cirrhosis to the development of acute-on-chronic liver failure (ACLF). Supportive treatment can improve AD patients, becoming recompensated. Little is known about the outcome of patients recompensated after AD. We hypothesise that different inflammasome activation is involved in ACLF development in compensated and recompensated patients.

DESIGN

249 patients with cirrhosis, divided into compensated and recompensated (previous AD), were followed prospectively for fatal ACLF development. Two external cohorts (n=327) (recompensation, AD and ACLF) were included. Inflammasome-driving interleukins (ILs), IL-1α (caspase-4/11-dependent) and IL-1β (caspase-1-dependent), were measured. In rats, bile duct ligation-induced cirrhosis and lipopolysaccharide exposition were used to induce AD and subsequent recompensation. IL-1α and IL-1β levels and upstream/downstream gene expression were measured.

RESULTS

Patients developing ACLF showed higher baseline levels of ILs. Recompensated patients and patients with detectable ILs had higher rates of ACLF development than compensated patients. Baseline CLIF-C (European Foundation for the study of chronic liver failure consortium) AD, albumin and IL-1α were independent predictors of ACLF development in compensated and CLIF-C AD and IL-1β in recompensated patients. Compensated rats showed higher IL-1α gene expression and recompensated rats higher IL-1β levels with higher hepatic gene expression. Higher IL-1β detection rates in recompensated patients developing ACLF and higher IL-1α and IL-1β detection rates in patients with ACLF were confirmed in the two external cohorts.

CONCLUSION

Previous AD is an important risk factor for fatal ACLF development and possibly linked with inflammasome activation. Animal models confirmed the results showing a link between ACLF development and IL-1α in compensated cirrhosis and IL-1β in recompensated cirrhosis.

HIV DNA reservoir and elevated PD-1 expression of CD4 T-cell subsets particularly persist in the terminal ileum of HIV-positive patients despite cART

OBJECTIVES

Despite its importance as an HIV anatomic sanctuary, little is known about the characteristics of the HIV reservoir in the terminal ileum (TI). In blood, the immune checkpoint inhibitor programmed-death-1 (PD-1) has been linked to the HIV reservoir and T-cell immune dysfunction. We thus evaluated PD-1 expression and cell-associated HIV DNA in memory CD4 T-cell subsets from TI, peripheral blood (PB) and rectum (RE) of untreated and treated HIV-positive patients to identify associations between PD-1 and HIV reservoir in other sites.

METHODS

Using mononuclear cells from PB, TI and RE of untreated HIV-positive (N = 6), treated (n = 18) HIV-positive and uninfected individuals (n = 16), we identified and sorted distinct memory CD4 T-cell subsets by flow cytometry, quantified their cell-associated HIV DNA using quantitative PCR and assessed PD-1 expression levels using geometric mean fluorescence intensity. Combined HIV-1 RNA in situ hybridization and immunohistochemistry was performed on ileal biopsy sections.

RESULTS

Combined antiretroviral therapy (cART)-treated patients with undetectable HIV RNA and significantly lower levels of HIV DNA in PB showed particularly high PD-1 expression in PB and TI, and high HIV DNA levels in TI, irrespective of clinical characteristics. By contrast, in treatment-naïve patients HIV DNA levels in memory CD4 T-cell subsets were high in PB and TI.

CONCLUSION

Elevated PD-1 expression on memory CD4 T-cells in PB and TI despite treatment points to continuous immune dysfunction and underlines the importance of evaluating immunotherapy in reversing HIV latency and T-cell reconstitution. As HIV DNA particularly persists in TI despite cART, investigating samples from TI is crucial in understanding HIV immunopathogenesis.

An Autochthonous Mouse Model of Myd88- and BCL2-Driven Diffuse Large B-cell Lymphoma Reveals Actionable Molecular Vulnerabilities

Based on gene expression profiles, diffuse large B cell lymphoma (DLBCL) is sub-divided into germinal center B cell-like (GCB) and activated B cell-like (ABC) DLBCL. Two of the most common genomic aberrations in ABC-DLBCL are mutations in MYD88, as well as BCL2 copy number gains. Here, we employ immune phenotyping, RNA-Seq and whole exome sequencing to characterize a Myd88 and Bcl2-driven mouse model of ABC-DLBCL. We show that this model resembles features of human ABC-DLBCL. We further demonstrate an actionable dependence of our murine ABC-DLBCL model on BCL2. This BCL2 dependence was also detectable in human ABC-DLBCL cell lines. Moreover, human ABC-DLBCLs displayed increased PD-L1 expression, compared to GCB-DLBCL. In vivo experiments in our ABC-DLBCL model showed that combined venetoclax and RMP1-14 significantly increased the overall survival of lymphoma bearing animals, indicating that this combination may be a viable option for selected human ABC-DLBCL cases harboring MYD88 and BCL2 aberrations.

TNF contributes to T-cell exhaustion in chronic L. mexicana infections of mice through PD-L1 up-regulation

Leishmania mexicana can produce chronic infections leading to exhausted T cell phenotypes, mediated by PD-1/PD-L1. Little is known on mechanisms that induce these inhibitory molecules in chronic leishmaniasis. We analyzed factors that contribute to exhausted phenotypes in chronic L. mexicana infections of mice. Our results show that draining lymph node cells express enhanced levels of PD-1/PD-L1. T lymphocytes producing low cytokine levels were also found. L. mexicana infection of dendritic cells (DCs) produced elevated amounts of TNF and showed up-regulation of PD-L1 expression. We provide evidence that T cells of chronic L. mexicana infections in mice are functionally exhausted due to chronic TNF production, which leads to PD-L1 up-regulation in DCs. We conclude that TNF has a fundamental role in promoting T cell exhaustion during chronic L. mexicana infections, which contributes to the inability of T cells to proliferate and produce pro-inflammatory cytokines, thus favoring disease progression.

TNF, IL-6, and IL-10 cytokines levels and their polymorphisms in renal function and time after transplantation

Cytokine polymorphisms can influence their plasma levels and thus affect the immune response in renal transplantation. A total of 146 renal transplant recipients (RTR) were classified into groups according to the estimated glomerular filtration rate (R1: < 60 and R2: ≥ 60 mL/min/1.73 m²) and time after transplantation (T1: 1 to 24, T2: 25 to 60, T3: 61 to 120, and T4: > 120 months after transplantation). The polymorphisms were genotyped by single specific primer-polymerase chain reaction. IL-10 was measured by ELISA and IL-6, and TNF levels were determined using Miliplex®. A higher frequency of the - 308G allele and the - 308G/G genotype, low-producer, was observed in the R1 group compared with R2. In addition, a higher frequency of the - 308A carriers, high-producer, was found in the R2 group. However, no significant difference was observed in cytokine levels when both groups were compared. Higher levels of IL-6 were observed in T1 compared with T2 and T4 groups. Lower IL-6 levels were found in T2 compared with T3 group. Lower levels of IL-10 were also found in T1 group in relation to T2, while higher levels of this cytokine were observed in T2 group compared with T3. The results suggest that the - 308G > A polymorphism in the TNF gene is associated with filtration function after renal transplantation, and IL-6 and IL-10 levels change according to the time after transplantation. Thus, the joint evaluation of - 308G > A polymorphism in TNF gene and IL-6 and IL-10 levels would provide a broader and effective view on the clinical monitoring of RTR.

Mitochondria, immunosenescence and inflammaging: a role for mitokines?

A global reshaping of the immune responses occurs with ageing, indicated as immunosenescence, where mitochondria and mitochondrial metabolism play an important role. However, much less is known about the role of mitochondrial stress response in this reshaping and in particular of the molecules induced by such response, collectively indicated as mitokines. In this review, we summarize the current knowledge on the role of mitokines in modulating immune response and inflammation focusing on GDF15, FGF21 and humanin and their possible involvement in the chronic age-related low-grade inflammation dubbed inflammaging. Although many aspects of their biology are still controversial, available data suggest that these mitokines have an anti-inflammatory role and increase with age. Therefore, we hypothesize that they can be considered part of an adaptive and integrated immune-metabolic mechanism activated by mitochondrial dysfunction that acts within the framework of a larger anti-inflammatory network aimed at controlling both acute inflammation and inflammaging.

Effects of Hepatitis B Surface Antigen on Virus-Specific and Global T Cells in Patients With Chronic Hepatitis B Virus infection

BACKGROUND & AIMS

Chronic hepatitis B virus (HBV) infection is characterized by the presence of defective viral envelope proteins (hepatitis B surface antigen [HBsAg]) and the duration of infection-most patients acquire the infection at birth or during the first years of life. We investigated the effects of these factors on patients' lymphocyte and HBV-specific T-cell populations.

METHODS

We collected blood samples and clinical data from 243 patients with HBV infection (3-75 years old) in the United Kingdom and China. We measured levels of HBV DNA, HBsAg, hepatitis B e antigen, and alanine aminotransferase; analyzed HBV genotypes; and isolated peripheral blood mononuclear cells (PBMCs). In PBMCs from 48 patients with varying levels of serum HBsAg, we measured 40 markers on nature killer and T cells by mass cytometry. PBMCs from 189 patients with chronic infection and 38 patients with resolved infections were incubated with HBV peptide libraries, and HBV-specific T cells were identified by interferon gamma enzyme-linked immune absorbent spot (ELISpot) assays or flow cytometry. We used multivariate linear regression and performed variable selection using the Akaike information criterion to identify covariates associated with HBV-specific responses of T cells.

RESULTS

Although T- and natural killer cell phenotypes and functions did not change with level of serum HBsAg, numbers of HBs-specific T cells correlated with serum levels of HBsAg (r = 0.3367; P < .00001). After we performed the variable selection, the multivariate linear regression model identified patient age as the only factor significantly associated with numbers of HBs-specific T cells (P = .000115). In patients younger than 30 years, HBs-specific T cells constituted 28.26% of the total HBV-specific T cells; this value decreased to 7.14% in patients older than 30 years.

CONCLUSIONS

In an analysis of immune cells from patients with chronic HBV infection, we found that the duration of HBsAg exposure, rather than the quantity of HBsAg, was associated with the level of anti-HBV immune response. Although the presence of HBs-specific T cells might not be required for the clearance of HBV infection in all patients, strategies to restore anti-HBV immune responses should be considered in patients younger than 30 years.

The Role of Macrophage-Inducible C-Type Lectin in Different Stages of Chronic Liver Disease

The macrophage-inducible C-type lectin (mincle) is part of the innate immune system and acts as a pattern recognition receptor for pathogen-associated molecular patterns (PAMPS) and damage-associated molecular patterns (DAMPs). Ligand binding induces mincle activation which consequently interacts with the signaling adapter Fc receptor, SYK, and NF-kappa-B. There is also evidence that mincle expressed on macrophages promotes intestinal barrier integrity. However, little is known about the role of mincle in hepatic fibrosis, especially in more advanced disease stages. Mincle expression was measured in human liver samples from cirrhotic patients and donors collected at liver transplantation and in patients undergoing bariatric surgery. Human results were confirmed in rodent models of cirrhosis and acute-on-chronic liver failure (ACLF). In these models, the role of mincle was investigated in liver samples as well as in peripheral blood monocytes (PBMC), tissues from the kidney, spleen, small intestine, and heart. Additionally, mincle activation was stimulated in experimental non-alcoholic steatohepatitis (NASH) by treatment with mincle agonist trehalose-6,6-dibehenate (TDB). In human NASH, mincle is upregulated with increased collagen production. In ApoE deficient mice fed high-fat western diet (NASH model), mincle activation significantly increases hepatic collagen production. In human cirrhosis, mincle expression is also significantly upregulated. Furthermore, mincle expression is associated with the stage of chronic liver disease. This could be confirmed in rat models of cirrhosis and ACLF. ACLF was induced by LPS injection in cirrhotic rats. While mincle expression and downstream signaling via FC receptor gamma, SYK, and NF-kappa-B are upregulated in the liver, they are downregulated in PBMCs of these rats. Although mincle expressed on macrophages might be beneficial for intestinal barrier integrity, it seems to contribute to inflammation and fibrosis once the intestinal barrier becomes leaky in advanced stages of chronic liver disease.

Comparison of silver nanoparticle-induced inflammatory responses between healthy and metabolic syndrome mouse models

Silver nanoparticles (AgNPs) are utilized in surgical implants and medical textiles, thus providing access to the circulation. While research has been conducted primarily in healthy models, AgNP-induced toxicity evaluations in disease conditions are critical, as many individuals have preexisting conditions. Specifically, over 20% of United States adults suffer from metabolic syndrome (MetS). It was hypothesized that MetS may increase susceptibility to AgNP-mediated toxicity due to induction of differential inflammation and altered biodistribution. Mice were injected with 2 mg/kg AgNPs, and organs assessed for inflammatory gene expression (TNF-α, CXCL1, CXCL2, CCL2, TGF-β, HO-1, IL-4, IL-13), and Ag content. AgNPs were determined to induce differential inflammation in healthy and MetS mice. While AgNP exposure increased TNF-α, CXCL1, TGF-β, HO-1, and IL-4 expression within healthy mouse spleens, MetS-treated animals demonstrated decreased CXCL1, IL-4, and IL-13 expression. Healthy and MetS mice livers exhibited similar inflammatory responses to one another. AgNPs localized primarily to the liver and spleen, although Ag was present in all examined organs. In organs of minor AgNP deposition, such as kidney, gene expression was variable. Induction of inflammatory genes did not correspond with biodistribution, suggesting disease-related variations in AgNP-mediated adverse responses. These findings indicate that disease may influence inflammation and biodistribution, impacting AgNP clinical applications.

Overexpression of T-bet in HIV infection is associated with accumulation of B cells outside germinal centers and poor affinity maturation

Nearly all chronic human infections are associated with alterations in the memory B cell (MBC) compartment, including a large expansion of CD19hiT-bethi MBC in the peripheral blood of HIV-infected individuals with chronic viremia. Despite their prevalence, it is unclear how these B cells arise and whether they contribute to the inefficiency of antibody-mediated immunity in chronic infectious diseases. We addressed these questions by characterizing T-bet-expressing B cells in lymph nodes (LN) and identifying a strong T-bet signature among HIV-specific MBC associated with poor immunologic outcome. Confocal microscopy and quantitative imaging revealed that T-bethi B cells in LN of HIV-infected chronically viremic individuals distinctly accumulated outside germinal centers (GC), which are critical for optimal antibody responses. In single-cell analyses, LN T-bethi B cells of HIV-infected individuals were almost exclusively found among CD19hi MBC and expressed reduced GC-homing receptors. Furthermore, HIV-specific B cells of infected individuals were enriched among LN CD19hiT-bethi MBC and displayed a distinct transcriptome, with features similar to CD19hiT-bethi MBC in blood and LN GC B cells (GCBC). LN CD19hiT-bethi MBC were also related to GCBC by B cell receptor (BCR)-based phylogenetic linkage but had lower BCR mutation frequencies and reduced HIV-neutralizing capacity, consistent with diminished participation in GC-mediated affinity selection. Thus, in the setting of chronic immune activation associated with HIV viremia, failure of HIV-specific B cells to enter or remain in GC may help explain the rarity of high-affinity protective antibodies.

KLF4 in Macrophages Attenuates TNFα-Mediated Kidney Injury and Fibrosis

BACKGROUND

Polarized macrophage populations can orchestrate both inflammation of the kidney and tissue repair during CKD. Proinflammatory M1 macrophages initiate kidney injury, but mechanisms through which persistent M1-dependent kidney damage culminates in fibrosis require elucidation. Krüppel-like factor 4 (KLF4), a zinc-finger transcription factor that suppresses inflammatory signals, is an essential regulator of macrophage polarization in adipose tissues, but the effect of myeloid KLF4 on CKD progression is unknown.

METHODS

We used conditional mutant mice lacking KLF4 or TNFα (KLF4's downstream effector) selectively in myeloid cells to investigate macrophage KLF4's role in modulating CKD progression in two models of CKD that feature robust macrophage accumulation, nephrotoxic serum nephritis, and unilateral ureteral obstruction.

RESULTS

In these murine CKD models, KLF4 deficiency in macrophages infiltrating the kidney augmented their M1 polarization and exacerbated glomerular matrix deposition and tubular epithelial damage. During the induced injury in these models, macrophage-specific KLF4 deletion also exacerbated kidney fibrosis, with increased levels of collagen 1 and α-smooth muscle actin in the injured kidney. CD11b+Ly6Chi myeloid cells isolated from injured kidneys expressed higher levels of TNFα mRNA versus wild-type controls. In turn, mice bearing macrophage-specific deletion of TNFα exhibited decreased glomerular and tubular damage and attenuated kidney fibrosis in the models. Moreover, treatment with the TNF receptor-1 inhibitor R-7050 during nephrotoxic serum nephritis reduced damage, fibrosis, and necroptosis in wild-type mice and mice with KLF4-deficient macrophages, and abrogated the differences between the two groups in these parameters.

CONCLUSIONS

These data indicate that macrophage KLF4 ameliorates CKD by mitigating TNF-dependent injury and fibrosis.

Therapeutic strategies for hepatitis B virus infection: towards a cure

Chronic hepatitis B virus (HBV) infection is a common cause of liver disease globally, with a disproportionately high burden in South-East Asia. Vaccines and nucleoside or nucleotide drugs are available and reduce both new infection rates and the development of liver disease in HBV-positive persons who adhere to long-term suppressive treatment. Although there is still considerable value in optimizing access to virus-suppressing regimens, the scientific and medical communities have embarked on a concerted journey to identify new antiviral drugs and immune interventions aimed at curing infection. The mechanisms and drug targets being explored are diverse; however, the field universally recognizes the importance of addressing the persistence of episomal covalently closed circular DNA, the existence of integrated HBV DNA in the host genome and the large antigen load, particularly of hepatitis B surface antigen. Another major challenge is to reinvigorate the exhausted immune response within the liver microenvironment. Ultimately, combinations of new drugs will be required to cure infection. Here we critically review the recent literature that describes the rationale for curative therapies and the resulting compounds that are being tested in clinical trials for hepatitis B.

Enzymatic Activity of HPGD in Treg Cells Suppresses Tconv Cells to Maintain Adipose Tissue Homeostasis and Prevent Metabolic Dysfunction

Regulatory T cells (Treg cells) are important for preventing autoimmunity and maintaining tissue homeostasis, but whether Treg cells can adopt tissue- or immune-context-specific suppressive mechanisms is unclear. Here, we found that the enzyme hydroxyprostaglandin dehydrogenase (HPGD), which catabolizes prostaglandin E₂ (PGE₂) into the metabolite 15-keto PGE₂, was highly expressed in Treg cells, particularly those in visceral adipose tissue (VAT). Nuclear receptor peroxisome proliferator-activated receptor-γ (PPARγ)-induced HPGD expression in VAT Treg cells, and consequential Treg-cell-mediated generation of 15-keto PGE₂ suppressed conventional T cell activation and proliferation. Conditional deletion of Hpgd in mouse Treg cells resulted in the accumulation of functionally impaired Treg cells specifically in VAT, causing local inflammation and systemic insulin resistance. Consistent with this mechanism, humans with type 2 diabetes showed decreased HPGD expression in Treg cells. These data indicate that HPGD-mediated suppression is a tissue- and context-dependent suppressive mechanism used by Treg cells to maintain adipose tissue homeostasis.

Prognostic nomogram incorporating inflammatory cytokines for overall survival in patients with aggressive non-Hodgkin's lymphoma

BACKGROUND

This study aimed to investigate the association of pre-treatment inflammatory status with survival time and to develop a prognostic nomogram incorporating inflammatory cytokines in non-Hodgkin's lymphoma.

METHODS

A total of 228 patients with diffuse large B-cell lymphoma (DLBCL) received R-CHOP-based regimens from a prospective randomized study (NCT01852435) were included as a training cohort. Other cohorts of 886 lymphoma patients were served as validation cohorts. Lymphocyte-monocyte ratio (LMR), serum levels of soluble interleukin s(IL)-2R, IL-6, IL-8, IL-10 and tumor necrosis factor-α (TNF-α), were assessed before treatment. Least absolute shrinkage and selection operator (LASSO) regression were used to select variables for nomogram of overall survival (OS). The predictive accuracy of the nomogram was determined by concordance index (C-index).

FINDINGS

The nomogram included lactate dehydrogenase (LDH), sIL-2R, TNF-α and decreased LMR. The C-index of the nomogram for OS prediction were range from 0.61 to 0.86 for training cohort of DLBCL and validation cohorts of DLBCL, PTCL, NKTCL and ASCT, which were superior to the predictive power of International Prognostic Index (IPI, 0.67 to 0.84) or NCCN-IPI (0.59 to 0.78), but not in those of indolent lymphoma like FL and MALT.

INTERPRETATIONS

The nomogram incorporating inflammatory cytokines provides a useful tool for risk stratification in aggressive non-Hodgkin's lymphomas. FUND: National Natural Science Foundation of China, the Shanghai Commission of Science and Technology, Multicenter Clinical Research Project by Shanghai Jiao Tong University School of Medicine, Clinical Research Plan of SHDC, and Chang Jiang Scholars Program.

Immune Exhaustion: Past Lessons and New Insights from Lymphocytic Choriomeningitis Virus

Lymphocytic choriomeningitis virus (LCMV) is a paradigm-forming experimental system with a remarkable track record of contributing to the discovery of many of the fundamental concepts of modern immunology. The ability of LCMV to establish a chronic infection in immunocompetent adult mice was instrumental for identifying T cell exhaustion and this system has been invaluable for uncovering the complexity, regulators, and consequences of this state. These findings have been directly relevant for understanding why ineffective T cell responses commonly arise during many chronic infections including HIV and HCV, as well as during tumor outgrowth. The principal feature of exhausted T cells is the inability to elaborate the array of effector functions necessary to contain the underlying infection or tumor. Using LCMV to determine how to prevent and reverse T cell exhaustion has highlighted the potential of checkpoint blockade therapies, most notably PD-1 inhibition strategies, for improving cellular immunity under conditions of antigen persistence. Here, we discuss the discovery, properties, and regulators of exhausted T cells and highlight how LCMV has been at the forefront of advancing our understanding of these ineffective responses.

Immunotherapy for Chronic Hepatitis B Virus Infection

While new therapies for chronic hepatitis C virus infection have delivered remarkable cure rates, curative therapies for chronic hepatitis B virus (HBV) infection remain a distant goal. Although current direct antiviral therapies are very efficient in controlling viral replication and limiting the progression to cirrhosis, these treatments require lifelong administration due to the frequent viral rebound upon treatment cessation, and immune modulation with interferon is only effective in a subgroup of patients. Specific immunotherapies can offer the possibility of eliminating or at least stably maintaining low levels of HBV replication under the control of a functional host antiviral response. Here, we review the development of immune cell therapy for HBV, highlighting the potential antiviral efficiency and potential toxicities in different groups of chronically infected HBV patients. We also discuss the chronic hepatitis B patient populations that best benefit from therapeutic immune interventions.

Targeting Innate and Adaptive Immune Responses to Cure Chronic HBV Infection

Fewer than 1% of chronic hepatitis B virus infections per year are cured with antiviral treatment. This creates a need for long-term treatment, which poses challenges for patients and health systems. Because cure is accompanied by recovery of antiviral immunity, a combination of direct-acting antiviral agents and immunotherapy are likely to be required. Extensive efforts have been made to identify determinants of the failed immune response to hepatitis B virus in patients with chronic infection. We review mechanisms of immune dysfunction in patients with chronic hepatitis B virus infection, immunotherapy strategies in development, and the challenges associated with successful implementation of immunotherapy.

The Regulatory Status Adopted by Lymph Node Dendritic Cells and T Cells During Healthy Aging Is Maintained During Cancer and May Contribute to Reduced Responses to Immunotherapy

Aging is associated with an increased incidence of cancer. One contributing factor could be modulation of immune cells responsible for anti-tumor responses, such as dendritic cells (DCs) and T cells. These immunological changes may also impact the efficacy of cancer immunotherapies in the elderly. The effects of healthy aging on DCs and T cells, and their impact on anti-mesothelioma immune responses, had not been reported. This study examined DCs and T cells in young (2–5 months; equivalent to 16–26 human years) and elderly (20–24 months; equivalent to 60–70 human years) healthy and mesothelioma-bearing C57BL/6J mice. During healthy aging, elderly lymph nodes adopted a regulatory profile, characterized by: (i) increased plasmacytoid DCs, (ii) increased expression of the adenosine-producing enzyme CD73 on CD11c⁺ cells, and (iii) increased expression of multiple regulatory markers (including CD73, the adenosine A2B receptor, CTLA-4, PD-1, ICOS, LAG-3, and IL-10) on CD8⁺ and CD4⁺ T cells, compared to lymph nodes from young mice. Although mesotheliomas grew faster in elderly mice, the increased regulatory status observed in healthy elderly lymph node DCs and T cells was not further exacerbated. However, elderly tumor-bearing mice demonstrated reduced MHC-I, MHC-II and CD80 on CD11c⁺ cells, and decreased IFN-γ by CD8⁺ and CD4⁺ T cells within tumors, compared to young counterparts, implying loss of function. An agonist CD40 antibody based immunotherapy was less efficient at promoting tumor regression in elderly mice, which may be due to: (i) failure of elderly CD8⁺ T cells to up-regulate perforin, and (ii) increased expression of multiple regulatory markers on CD11c⁺ cells and T cells in elderly tumor-draining lymph nodes (including CD73, PD-1, ICOS, LAG-3, and TGF-β). Our findings suggest that checkpoint blockade may improve responses to immunotherapy in elderly hosts with mesothelioma, and warrants further investigation.