T-cell exhaustion in immune-mediated inflammatory diseases: New implications for immunotherapy

The role of cell exhaustion in lepromatous leprosy

Leprosy is a neglected chronic infectious disease caused by Mycobacterium leprae or M. lepromatosis, representing a public health concern in several low-income countries. In Brazil, most patients develop lepromatous leprosy, a clinical form characterized by poor bacillary control due to T helper 2 cells, M2 macrophages, and accentuated humoral immunity. Despite extensive studies, the complete mechanism of the disease is not fully understood. The evasion mechanisms used by the pathogen likely involve cellular exhaustion, which can arise from chronic antigen stimulation, leading to dysfunction at immune checkpoints, a progressive loss of T lymphocyte effector function, and low production of proinflammatory cytokines. Our study investigated the contribution of cellular exhaustion to the hyporesponsiveness of lepromatous leprosy patients by evaluating the classical markers PD-1 and LAG-3, their ligands PD-L1 and PD-L2, and the functional activity of cells after PD-1 blockade, using flow cytometry, immunofluorescence, and gene expression analyses in both blood and skin. Our work shows for the first time that LAG-3 is increased in the skin lymphocytes of lepromatous patients, as well as membrane-bound and soluble PD-1. Furthermore, its classical ligands, PD-L1 and PD-L2, are more available for interaction in all monocyte subsets in these patients. We also identified that PD-1 blockade induces an increase in IFN-γ+ and TNF+ T lymphocytes. Taken together, our data suggest that exhaustion markers contribute to the hyporesponsive profile of lepromatous patients, and that PD-1 blockade could contribute to the reestablishment of lymphocyte effector action and potentially become part of multidrug therapy in the future.

Ara h 2105-124-Specific TH2A Cells Drive Peanut Allergy in DRB1*15:01 Individuals: A Detailed Epitope Analysis

BACKGROUND

The IgE-mediated CD4 T-cell response to peanut (Arachis hypogaea) is heterogeneous, yet TH2 cells remain central drivers of pathology. This study aimed to dissect this complexity at the epitope level by focusing on the HLA-DRB1*15:01-DRB5*01:01 haplotype. Specifically, we examined how distinct epitope-specific T-cell subsets shape the immunological landscape of peanut allergy in peanut-allergic (PA) versus non-peanut-allergic (NPA) individuals.

METHODS

Using in vitro and ex vivo MHC-II tetramer approaches, the phenotype, frequency, function, and transcriptome of CD4 T-cell responses to novel Ara h epitopes were assessed. Bulk RNA sequencing further characterised these T cells, allowing identification of subsets associated with TH2 polarisation in PA individuals.

RESULTS

Eleven HLA-DRB1*15:01 and DRB5*01:01-restricted epitopes were identified in Ara h 1, 2, 3, 6, 7, and 8 using tetramer-guided epitope mapping on cell lines, followed by ex vivo validation in peripheral blood. T-cell phenotype was epitope-dependent, with a distinct TH2A population specific to the epitope Ara h 2105-124 (Ara h 2 p14) detected only in PA donors. These TH2A cells were phenotypically and transcriptionally distinct, marked by high CRTH2/CD161, low CD27, IL-5 production, and gene enrichment in cytokine signalling and lipid metabolism. Other epitope-specific T-cell subsets displayed more heterogeneous gene profiles related to immune activation, differentiation, and antigen presentation, underscoring the complexity of peanut-specific responses even within a single HLA haplotype.

CONCLUSION

These findings reveal that the strong TH2 bias in DRB1*15:01-DRB5*01:01 PA individuals arises from a distinct subset of Ara h 2 p14-specific TH2A cells characterised by a specialised metabolic and cytokine signalling program. At the same time, the functional diversity observed in non-Ara h 2 p14 subsets highlights the potential for leveraging these populations in tolerance-promoting therapies. Understanding the epitope-level heterogeneity of peanut-specific T-cells provides insight into the epitope-specific mechanisms driving peanut allergy and has potential implications for therapeutic interventions.

Evaluation of the influenza vaccine protection in the house dust mite-induced chronic allergic asthma mice model and the evaluation of squalene oil in water emulsion as an adjuvant candidate

BACKGROUND

Despite the importance of influenza vaccination in asthma patients, the efficacy of this vaccine in asthma has not been well elucidated. We aimed to compare the efficacy of an influenza vaccine of the asthmatic and control mice. We also evaluated the efficacy of AddaVax™ as an adjuvant candidate, which is equivalent to the MF59 influenza vaccine adjuvant in the elderly.

METHOD

House dust mite extracts were intranasally injected into six-week-old female BALB/c mice to induce chronic allergic asthma. Antibody responses after split-inactivated A/Puerto Rico/8/34 H1N1 influenza vaccination with or without AddaVax™ adjuvant were measured using ELISA. Homologous viral protection was determined by measuring the survival rate, lung inflammation level, and lung virus titer after challenge with the human influenza virus strain A/Puerto Rico/8/1934 H1N1. Antigen-specific T cell responses were determined using flow cytometry.

RESULT

The chronic asthma mice immunized with split-inactivated A/Puerto Rico/8/34 H1N1 influenza vaccine showed significant weight loss and higher lung viral load after homologous influenza infection than naïve vaccinated mice. Antigen-specific IgG, IgG1, and IgG2a production did not differ between the naïve and asthma mice. However, serum HI titer was lower in asthma-vaccinated mice after infection. The application of AddaVax™ to a vaccine for mice with asthma enhanced the efficacy of homologous antiviral protection but elicited eosinophil infiltration in the lungs after homologous influenza virus infection.

CONCLUSION

The immune response after split inactivated A/PR8 vaccine differed between asthma and naïve mice, particularly in terms of antibody activity and T cell populations. This study enhances our understanding of how asthma status may influence the effectiveness of influenza vaccine and offers insights into the AddaVax™-induced eosinophilic inflammation, guiding the development of virus vaccine strategies for both healthy individuals and asthma patients.

Modulating the PD-1-FABP5 axis in ILC2s to regulate adipose tissue metabolism in obesity

Obesity is closely linked to metabolic dysregulation and chronic inflammation, which significantly impact immune cell functions in adipose tissue. Type 2 innate lymphoid cells (ILC2s) have emerged as key regulators of energy homeostasis, positioning them as promising targets for obesity management. However, the mechanisms governing ILC2 activity and their therapeutic potential in obesity are not fully understood. In this study, we demonstrate that ILC2s in obese adipose tissue exhibit increased PD-1 expression, leading to an exhausted phenotype with diminished cytokine production and proliferation. Elevated osteopontin (OPN) levels in adipose tissue are associated with higher PD-1 expression on ILC2s, while adipocyte-derived PD-L1 interacts with PD-1 to further impair ILC2 functionality. Importantly, blocking PD-1 signaling prevents weight gain and alleviates obesity-related metabolic dysfunctions. In addition, the adoptive transfer of PD-1-deficient ILC2s reduces diabetic phenotypes in obese models. Mechanistically, PD-1 signaling drives metabolic reprogramming in ILC2s, affecting fatty acid uptake and energy metabolism through the downregulation of fatty acid binding protein 5 (FABP5). These results, corroborated by findings in human adipose tissue, suggest a conserved OPN-PD-1 axis. Our study identifies the OPN-PD-1-FABP5 pathway as a crucial regulator of ILC2 function in adipose tissue and presents an emerging immune cell-based therapeutic target for obesity treatment.

CD8+ T cell-based immunotherapy: Promising frontier in human diseases

The abundant cell components of the adaptive immune system called T lymphocytes (T cells) play important roles in mediating immune responses to eliminate the invaders and create the memory of the germs to form a new immunity for the next encounter. Among them, cytotoxic T cells expressing cell-surface CD8 are the most critical effector cells that directly eradicate the target infected cells by recognizing antigens presented by major histocompatibility complex class I molecules to protect our body from pathological threats. In the continuous evolution of immunotherapy, various CD8+ T cell-based therapeutic strategies have been developed based on the role and molecular concept of CD8+ T cells. The emergence of such remarkable therapies provides promising hope for multiple human disease treatments such as autoimmunity, infectious disease, cancer, and other non-infectious diseases. In this review, we aim to discuss the current knowledge on the utilization of CD8+ T cell-based immunotherapy for the treatment of various diseases, the molecular basis involved, and its limitations. Additionally, we summarize the recent advances in the use of CD8+ T cell-based immunotherapy and provide a comprehensive overview of CD8+ T cells, including their structure, underlying mechanism of function, and markers associated with CD8+ T cell exhaustion. Building upon these foundations, we delineate the advancement of CD8+ T cell-based immunotherapies with fundamental operating principles followed by research studies, and challenges, as well as illustrate human diseases involved in this development.

Deciphering T-cell exhaustion in the tumor microenvironment: paving the way for innovative solid tumor therapies

In solid tumors, the tumor microenvironment (TME) is a complex mix of tumor, immune, stromal cells, fibroblasts, and the extracellular matrix. Cytotoxic T lymphocytes (CTLs) constitute a fraction of immune cells that may infiltrate into the TME. The primary function of these T-cells is to detect and eliminate tumor cells. However, due to the immunosuppressive factors present in the TME primarily mediated by Myeloid-Derived Suppressor Cells (MDSCs), Tumor associated macrophages (TAMs), Cancer Associated Fibroblasts (CAFs) as well as the tumor cells themselves, T-cells fail to differentiate into effector cells or become dysfunctional and are unable to eliminate the tumor. In addition, chronic antigen stimulation within the TME also leads to a phenomenon, first identified in chronic lymphocytic choriomeningitis virus (LCMV) infection in mice, where the T-cells become exhausted and lose their effector functions. Exhausted T-cells (Tex) are characterized by the presence of remarkably conserved inhibitory receptors, transcription and signaling factors and the downregulation of key effector molecules. Tex cells have been identified in various malignancies, including melanoma, colorectal and hepatocellular cancers. Recent studies have indicated novel strategies to reverse T-cell exhaustion. These include checkpoint inhibitor blockade targeting programmed cell death protein 1 (PD-1), T-cell immunoglobulin and mucin-domain containing-3 (Tim-3), cytotoxic T-lymphocyte associated protein 4 (CTLA-4), or combinations of different immune checkpoint therapies (ICTs) or combination of ICTs with cytokine co-stimulation. In this review, we discuss aspects of T-cell dysfunction within the TME with a focus on T-cell exhaustion. We believe that gaining insight into the mechanisms of T-cell exhaustion within the TME of human solid tumors will pave the way for developing therapeutic strategies to target and potentially re-invigorate exhausted T-cells in cancer.

T Cell Exhaustion in Allergic Diseases and Allergen Immunotherapy: A Novel Biomarker?

PURPOSE OF REVIEW

This review explores the emerging role of T cell exhaustion in allergic diseases and allergen immunotherapy (AIT). It aims to synthesize current knowledge on the mechanisms of T cell exhaustion, evaluate its potential involvement in allergic inflammation, and assess its implications as a novel biomarker for predicting and monitoring AIT efficacy.

RECENT FINDINGS

Recent studies highlight that T cell exhaustion, characterized by co-expression of inhibitory receptors (e.g., PD-1, CTLA-4, TIM-3), diminished cytokine production, and altered transcriptional profiles, may suppress type 2 inflammation in allergic diseases. In allergic asthma, exhausted CD4 + T cells exhibit upregulated inhibitory receptors, correlating with reduced IgE levels and airway hyperreactivity. During AIT, prolonged high-dose allergen exposure drives allergen-specific Th2 and T follicular helper (Tfh) cell exhaustion, potentially contributing to immune tolerance. Notably, clinical improvements in AIT correlate with depletion of allergen-specific Th2 cells and persistent expression of exhaustion markers (e.g., PD-1, CTLA-4) during maintenance phases. Blockade of inhibitory receptors (e.g., PD-1) enhances T cell activation, underscoring their dual regulatory role in allergy. T cell exhaustion represents a double-edged sword in allergy: it may dampen pathological inflammation in allergic diseases while serving as a mechanism for AIT-induced tolerance. The co-expression of inhibitory receptors on allergen-specific T cells emerges as a promising biomarker for AIT efficacy. Future research should clarify the transcriptional and metabolic drivers of exhaustion in allergy, validate its role across diverse allergic conditions, and optimize strategies to harness T cell exhaustion for durable immune tolerance. These insights could revolutionize therapeutic approaches and biomarker development in allergy management.

Microbiome Integrity Enhances the Efficacy and Safety of Anticancer Drug

The intricate relationship between anticancer drugs and the gut microbiome influences cancer treatment outcomes. This review paper focuses on the role of microbiome integrity in enhancing the efficacy and safety of anticancer drug therapy, emphasizing the pharmacokinetic interactions between anticancer drugs and the gut microbiota. It explores how disruptions to microbiome composition, or dysbiosis, can alter drug metabolism, immune responses, and treatment side effects. By examining the mechanisms of microbiome disruption caused by anticancer drugs, this paper highlights specific case studies of drugs like cyclophosphamide, 5-fluorouracil, and irinotecan, and their impact on microbial diversity and clinical outcomes. The review also discusses microbiome-targeted strategies, including prebiotics, probiotics, postbiotics, and fecal microbiota transplantation (FMT), as promising interventions to enhance cancer treatment. Furthermore, the potential of microbiome profiling in personalizing therapy and integrating these interventions into clinical practice is explored. Finally, this paper proposes future research directions, including developing novel biomarkers and a deeper comprehension of drug-microbiome interactions, to respond to current gaps in knowledge and improve patient outcomes in cancer care.

Galectin-3 secreted by triple-negative breast cancer cells regulates T cell function

Triple-negative breast cancer (TNBC) is an aggressive subtype that accounts for 10-15 % of breast cancer. Current treatment of high-risk early-stage TNBC includes neoadjuvant chemo-immune therapy. However, the substantial variation in immune response prompts an urgent need for new immune-targeting agents. This requires a comprehensive understanding of TNBC's tumor microenvironment. We recently demonstrated that Galectin-3 (Gal-3) binding protein/Gal-3 complex secreted by TNBC cells induces immunosuppression, through inhibiting CD45 signaling in T cells. Here, we further investigated the interaction between secreted Gal-3 and T cells in TNBC. Using CRISPR/Cas9 gene editing of the TNBC MDA-MB-231 cell-line, we obtained Gal-3 negative(neg) clones. We studied these in an in-vitro model, co-cultured with peripheral blood mononuclear cells (PBMC) to imitate immune-tumor interaction, and in an in-vivo model, when implanted in mice. Gal-3neg tumors in mice had decelerated tumor growth after PBMC inoculation. In contrast, the Gal-3 positive(pos) tumors continued growing despite PBMC inoculation, and tumor T regulatory cell (CD4/FoxP3+) infiltration increased. RNA sequencing of T cells from women with TNBC with elevated plasma levels of Gal-3 revealed significantly lower expression of oxidative phosphorylation genes than in T cells from healthy women. Similarly, in our in-vitro model, the decreased expression of oxidative phosphorylation genes and mitochondrial dysfunction resulted in a significant increase in CD8 intracellular reactive oxygen species. Consequently, T exhausted cells (CD8/PD1/Tim3/Lag3+) significantly increased in PBMC co-cultured with Gal-3pos TNBCs. To conclude, we revealed a novel TNBC-related Gal-3 suppressor mechanism that involved upregulation of CD4 T regulatory and of CD8 T exhausted cells.

Immunosenescence and age-related immune cells: causes of age-related diseases

Immunosenescence is a weakening of the immune system due to aging, characterized by changes in immune cells and dysregulated immune function. Age-related immune cells are increasing with aging. They are associated with chronic prolonged inflammation, causing tissue dysfunction and age-related diseases. Here, we discuss increased pro-inflammatory activity of aged macrophages, accumulation of lymphocytes with an age-associated phenotype, and specific alterations in both functions and characteristics of these immune cells. These cellular changes are associated with development of age-related diseases. Additionally, we reviewed various therapeutic strategies targeting age-related immunosenescence, providing pathways to mitigate effects of age-related diseases.

The immunoregulatory effects of scoparone on immune-mediated inflammatory diseases

Scoparone (SCO), also known as 6,7-Dimethoxycoumarin, is a naturally occurring bioactive ingredient originally derived from Chinese herb Artemisiae Scopariae Herba (Yin-Chen-Hao). Previous studies have shown that it is effective in treating some of the liver diseases. Beyond its hepatoprotective effects, an expanding body of research has underscored the immunoregulatory properties of SCO, indicating its potential therapeutic benefits for autoimmune and other inflammatory diseases. Over the past decade, significant advances have been made in understanding the mechanistic insights into its effects on immune-mediated diseases as well as liver diseases. SCO has an impact on various immune cells, including mast cells, monocytes, macrophages, neutrophils and T cells, and affects a broad range of intracellular signaling pathways, including TLR4/Myd88/NFκB, TGFβR/Smad3 and JNK/Sab/SHP-1 etc. Therefore, this review not only summarizes the immunomodulatory and therapeutic effects of SCO on immune-based inflammatory diseases (IMIDs), such as inflammatory bowel disease, osteoarthritis, allergic rhinitis, acute lung injury, type 1 diabetes and neuroinflammatory diseases etc., but also provides a comprehensive summary of its therapeutic effects on hepatic diseases, including non-alcoholic steatohepatitis, fulminant hepatic failure and hepatic fibrosis. In this review, we also include the broad impacts of SCO on intracellular signaling pathways, such as TLR4/Myd88/NFκB, TGFβR/Smad3, Nrf2/P38, JAK2/STAT3 and JNK/Sab/SHP-1 etc. Further researches on SCO may help understand its in-depth mechanisms of action and pave the way for the development of novel drugs to prevent and treat various immune-mediated inflammatory disorders as well as hepatic diseases, thereby significantly advancing its innovations and pharmaceutical applications.

Effect of gut microbiota changes on cytokines IL-10 and IL-17 levels in liver transplantation patients

BACKGROUND

Liver transplantation (LT) is a critical intervention for individuals with end-stage liver disease; yet, post-transplant problems, especially infections, graft rejection, and chronic liver disease, are often linked to systemic inflammation. Cytokines, small signaling molecules, significantly influence immune responses during and post-liver transplantation. Nonetheless, the intricate relationships among cytokines, immune responses, and the gut microbiota, especially gut dysbiosis, are still inadequately comprehended. Thus, this study aims to identify the gut microbiota (GM) and determine their relationship to cytokines (IL-17 and IL-10) in LT patients, due to their importance in enhancing the recovery rate.

RESULT

The research included 31 liver transplant (LT) patients from the Gastroenterology Surgical Center at Mansoura University, resulting in the collection of 174 stool and blood samples from all participants. Fourteen bacterial species have been identified in samples collected at three intervals: one week before, one week post, and two weeks post LT. A change in gut microbiota composition was noted, characterized by a rise in potentially pathogenic bacteria such as Enterococci and Enterobacteriaceae (including Escherichia coli and Klebsiella) and a reduction in beneficial bacteria such as Bacteroidetes and Firmicutes. The examination of patient demographic and clinical data revealed no significant correlations between sex, age, or diagnostic categories and gut microbiota composition. The findings of the Multivariate Analysis of Variance (MANOVA) indicated a substantial effect of gut microbiota composition on cytokine levels (IL-10 and IL-17), with all tests producing p-values of 0.001. The assessment of cytokine levels indicated fluctuating variations at several time points following surgery. IL-10 levels in the GM groups exhibited a statistically significant elevation during the second week post-surgery (p = 0.036), suggesting a potential recovery-related anti-inflammatory response. In contrast, IL-17 levels rose in the NI group over time, indicating a transition to a pro-inflammatory condition.

CONCLUSION

This study emphasizes the pivotal role of the gut microbiota in regulating immune responses following transplantation.

Immune cell-enriched single-cell RNA sequencing unveils the interplay between infiltrated CD8+ T resident memory cells and choroid plexus epithelial cells in Alzheimer's disease

Alzheimer's disease (AD) is a progressive neurological disorder and the leading cause of dementia. Despite significant efforts, treatment strategies targeting amyloid-β have been less successful than anticipated. Recently, the role of neuroinflammation and adaptive immune response in AD pathogenesis has gained attention. Here, we performed immune cell-enriched single-cell RNA sequencing of brain parenchymal cells from 12-month-old 5xFAD, an AD mouse model. We analyzed 11,587 single cells and found distinct differences in T cell and choroid plexus cell populations between 5xFAD mouse and littermate control. Subsequent sub-clustering of T cells in the 5xFAD mouse revealed distinct subtypes, with CD8+ resident memory T cells (TRM) being the most prevalent T cell type. In addition, we observed an increase in T cell exhaustion markers, including Pdcd1, Ctla4, and Havcr2, with a particularly significant elevation of PD-1 and TIM-3 in CD8+ TRM in 5xFAD mouse. Furthermore, choroid plexus (ChP) epithelial cells showed altered gene expression patterns, with higher expression of MHC class I and Type I IFN-stimulated genes in 5xFAD mouse compared to the control mouse, suggesting an association with clonal expansion of AD-specific T cells in the brain. Through single-cell RNA sequencing (scRNA-seq) analysis, our study highlights the potential role of resident memory CD8+ T cell and their possible interactions with ChP epithelial cells. This study provides an exploration of the brain microenvironment landscape in AD, revealing critical insights into its underlying mechanisms.

Effect of immunoadsorption on clinical presentation and immune alterations in COVID-19-induced and/or aggravated ME/CFS

Autoantibodies (AABs) are currently being investigated as causative or aggravating factors during post-COVID. In this study, we analyze the effect of immunoadsorption therapy on symptom improvement and the relationship with immunological parameters in post-COVID patients exhibiting symptoms of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) induced or aggravated by an SARS-CoV-2 infection. This observational study includes 12 post-COVID patients exhibiting a predominance of ME/CFS symptoms alongside increased concentrations of autonomic nervous system receptor (ANSR) autoantibodies and neurological impairments. We found that following immunoadsorption therapy, the ANSR AABs were nearly eliminated from the patients' blood. The removal of immunoglobulin G antibodies was accompanied by a decrease of pro-inflammatory cytokines including interleukin (IL)-4, IL-2, IL-1β, tumor necrosis factor, and IL-17A serum levels, and a significant reduction of soluble spike protein. Notably, a strong positive correlation between pro-inflammatory cytokines and ASNR-AABs β1, β2, M3, and M4 was observed in spike protein-positive patients, whereas no such correlation was evident in spike protein-negative patients. Thirty days post-immunoadsorption therapy, patients exhibited notable improvement in neuropsychological function and a modest but statistically significant amelioration of hand grip strength was observed. However, neither self-reported symptoms nor scores on ME/CFS questionnaires showed a significant improvement and a rebound of the removed proteins occurring within a month.

Advancing Treatment for Leishmaniasis: From Overcoming Challenges to Embracing Therapeutic Innovations

Protozoan parasite infections, particularly leishmaniasis, present significant public health challenges in tropical and subtropical regions, affecting socio-economic status and growth. Despite advancements in immunology, effective vaccines remain vague, leaving drug treatments as the primary intervention. However, existing medications face limitations, such as toxicity and the rise of drug-resistant parasites. This presents an urgent need to identify new therapeutic targets for leishmaniasis treatment. Understanding the complex life cycle of Leishmania and its survival in host macrophages can provide insights into potential targets for intervention. Current treatments, including antimonials, amphotericin B, and miltefosine, are constrained by side effects, costs, resistance, and reduced efficacy. Exploring novel therapeutic targets within the parasite's physiology, such as key metabolic enzymes or essential surface proteins, may lead to the development of more effective and less toxic drugs. Additionally, innovative strategies like drug repurposing, combination therapies, and nanotechnology-based delivery systems could enhance efficacy and combat resistance, thus improving anti-leishmanial therapies.

Host directed immunotherapy for chronic infections and cancer

Host-directed immunotherapy (HDI) is emerging as a transformative strategy in managing chronic diseases by leveraging the host's immune system to combat disease. This innovative approach has shown promise in a range of conditions, including cancer and parasitic infections. In oncology, HDI aims to enhance the body's natural immune response against cancer cells through mechanisms such as immune checkpoint inhibition, monoclonal antibodies, and cytokine therapies. These strategies are designed to boost the immune system's ability to recognize and destroy tumors, improving patient outcomes and offering alternatives to traditional cancer treatments. Similarly, in parasitic infections, HDI focuses on strengthening the host's immune defenses to control and eradicate those infections. For diseases like malaria, leishmaniasis, and Chagas disease, HDI strategies may involve adjuvants or immune modulators that amplify the body's ability to target and eliminate parasites. By optimizing immune responses and reducing reliance on conventional treatments, HDI holds the potential to revolutionize therapeutic approaches across various chronic diseases. This chapter highlights the flexibility and potential of HDI in advancing treatments, offering novel ways for improving patient care and disease management.

How Co-Stimulatory/Inhibitory Molecules Vary Across Immune Cell Subtypes in the Severity of Systemic Lupus Erythematosus Compared to Controls

BACKGROUND

Co-stimulatory and co-inhibitory molecules are critical to T cell responses and involved in the pathogenesis of systemic lupus erythematosus (SLE). This study aimed to comprehensively analyze the surface expression of these molecules in various phenotypic immune cells, comparing the differences between various levels of the severity in SLE and control groups.

METHODS

Peripheral blood mononuclear cells (PBMCs) were isolated using Ficoll-Paque from blood samples of severe SLE patients (treatment with immunosuppressants), mild SLE patients (excluding those with persistent proteinuria or thrombocytopenia), and healthy controls (n = 10 each). PBMCs were stimulated for 48 h. The cells were stained with anti-CD3, CD4, CD28, PD-1, and CTLA-4 antibodies and analyzed by flow cytometry. Differences between groups were assessed using the Kruskal-Wallis test and Mann-Whitney U-test, with median values and statistical significance (p < 0.05) reported.

RESULTS

The results showed that CD28 expression was significantly higher in SLE patients compared to controls, with the highest levels in mild SLE. However, CD3+ CD28+ and CD4+ CD28+ cells were more prevalent in controls (p = 0.032 and 0.017, respectively). Mild SLE patients exhibited the highest CTLA-4 expression, with significant differences from severe SLE and controls (p = 0.030 and 0.037, respectively). PD-1 expression was lowest in severe SLE but highest in mild SLE within CD3+ CD4+ cells (p = 0.001). After 48 h of activation, CD4+ CTLA4+ and CD3+ CTLA4+ expression levels were significantly higher in controls compared to SLE groups.

CONCLUSIONS

Our study highlighted that the expression of CD28, CTLA-4, and PD-1 in lymphocytes and specific T cell subsets was various according the severity of SLE in patients, underscoring their roles in disease pathogenesis.

Immune exhaustion in ME/CFS and long COVID

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) and long COVID are debilitating multisystemic conditions sharing similarities in immune dysregulation and cellular signaling pathways contributing to the pathophysiology. In this study, immune exhaustion gene expression was investigated in participants with ME/CFS or long COVID concurrently. RNA was extracted from peripheral blood mononuclear cells isolated from participants with ME/CFS (n = 14), participants with long COVID (n = 15), and healthy controls (n = 18). Participants with ME/CFS were included according to Canadian Consensus Criteria. Participants with long COVID were eligible according to the case definition for "Post COVID-19 Condition" published by the World Health Organization. RNA was analyzed using the NanoString nCounter Immune Exhaustion gene expression panel. Differential gene expression analysis in ME/CFS revealed downregulated IFN signaling and immunoglobulin genes, and this suggested a state of immune suppression. Pathway analysis implicated dysregulated macrophage activation, cytokine production, and immunodeficiency signaling. Long COVID samples exhibited dysregulated expression of genes regarding antigen presentation, cytokine signaling, and immune activation. Differentially expressed genes were associated with antigen presentation, B cell development, macrophage activation, and cytokine signaling. This investigation elucidates the intricate role of both adaptive and innate immune dysregulation underlying ME/CFS and long COVID, emphasizing the potential importance of immune exhaustion in disease progression.

The miRNA and PD-1/PD-L1 signaling axis: an arsenal of immunotherapeutic targets against lung cancer

Lung cancer is a severe challenge to the health care system with intrinsic resistance to first and second-line chemo/radiotherapies. In view of the sterile environment of lung cancer, several immunotherapeutic drugs including nivolumab, pembrolizumab, atezolizumab, and durvalumab are currently being used in clinics globally with the intention of releasing exhausted T-cells back against refractory tumor cells. Immunotherapies have a limited response rate and may cause immune-related adverse events (irAEs) in some patients. Hence, a deeper understanding of regulating immune checkpoint interactions could significantly enhance lung cancer treatments. In this review, we explore the role of miRNAs in modulating immunogenic responses against tumors. We discuss various aspects of how manipulating these checkpoints can bias the immune system's response against lung cancer. Specifically, we examine how altering the miRNA profile can impact the activity of various immune checkpoint inhibitors, focusing on the PD-1/PD-L1 pathway within the complex landscape of lung cancer. We believe that a clear understanding of the host's miRNA profile can influence the efficacy of checkpoint inhibitors and significantly contribute to existing immunotherapies for lung cancer patients. Additionally, we discuss ongoing clinical trials involving immunotherapeutic drugs, both as standalone treatments and in combination with other therapies, intending to advance the development of immunotherapy for lung cancer.

The transcription regulator ID3 maintains tumor-specific memory CD8+ T cells in draining lymph nodes during tumorigenesis

During tumorigenesis, the recently identified tumor-specific memory T cells in draining lymph nodes (TdLN-TTSM cells) play a pivotal role in tumor repression that gives rise to progenitor exhausted T (TPEX) cells and further replenishes tumor-specific CD8+ T cells residing in the tumor microenvironment (TME). However, how TTSM cells are maintained in TdLN is largely unknown. Here, we show that the transcription regulator ID3 (inhibitor of DNA binding 3) is highly expressed by TTSM cells compared with other CD8+ T cell subsets. The deficiency of ID3 significantly interrupts the maintenance of TTSM and TPEX cells, resulting in decreased tumor-infiltrating CD8+ T cells and impaired tumor control. Consistent with this, overexpression of ID3 in CD8+ T cells increases the TTSM cell population and enhances the anti-tumor immune response.

Immune Biomarkers at Birth Predict Lower Respiratory Tract Infection Risk in a Large Birth Cohort

Lower respiratory tract infections (LRTIs) remain the leading cause of infant morbidity and mortality worldwide and affect long-term respiratory health. Identifying immunological determinants of LRTI susceptibility may help stratify disease risk and identify therapies. This study aimed to identify neonatal immunological factors predicting LRTI risk in infancy. Cord blood plasma from 191 neonates from the Boston Birth Cohort was analyzed for 28 soluble immune factors. LRTI was defined as bronchiolitis, bronchitis, or pneumonia during the first year of life. Welch's t-test demonstrated significantly higher log10 transformed concentrations of IL-17 and IFNγ in the LRTI group compared to neonates without LRTI in the first year of life (p < 0.05). Risk associations were determined using multivariate survival models. There were 29 infants with LRTIs. High cord blood levels of IFNγ (aHR = 2.35, 95% CI 1.07-5.17), TNF-β (aHR = 2.86, 95% CI 1.27-6.47), MIP-1α (aHR = 2.82, 95% CI 1.22-6.51), and MIP-1β (aHR = 2.34, 95% CI 1.05-5.20) were associated with a higher risk of LRTIs. RANTES was associated with a lower risk (aHR = 0.43, 95% CI 0.19-0.97). Soluble immune factors linked to antiviral immunity (IFNγ) and cytokines mediating inflammatory responses (TNF-β), and cell homing (MIP-1α/b), at birth were associated with an increased risk of LRTIs during infancy.

Systemic sclerosis-associated pulmonary arterial hypertension is characterized by a distinct peripheral T helper cell profile

OBJECTIVES

Systemic sclerosis (SSc) is characterized by multiple clinical manifestations. Vasculopathy is a main disease hallmark and ranges in severity from an exacerbated Raynaud phenomenon to pulmonary arterial hypertension (PAH). The potential involvement of the immune system in SSc-associated vascular abnormalities is not clear. Here, we set out to study SSc-related immune parameters and determine whether and which peripheral T cell subsets associate with vascular severity in SSc patients.

METHODS

Peripheral blood and clinical data were collected from 30 SSc patients, 5 patients with idiopathic PAH and 15 age and sex-matched healthy donors (HD). In this cross-sectional cohort, SSc patients with PAH (n = 15) were matched for their age, sex and medication with SSc patients with no signs of PAH (n = 15). Lymphocyte subsets were quantified by multi-colour flow cytometry.

RESULTS

SSc patients exhibited elevated percentages of T peripheral helper cells (Tph), CD4+GZMB+ T cells and decreased levels of Th1 cells compared with HD. Increased presence of both CD4+ and CD8+ exhausted-like (CD28-) T cells, characterized by raised cytokine and cytotoxic signature, was also observed in SSc compared with HD blood. Furthermore, IL-4 expressing CD4+CD8+ T cells were significantly increased in SSc peripheral blood. Interestingly, the presence of PAH in SSc was accompanied by a distinct T helper profile, characterized by raised percentages of Th17 and Tph cells.

CONCLUSION

SSc patients with severe vasculopathy (presence of PAH) exhibited a distinct T cell profile, suggesting a potential role of auto-immune inflammation in SSc vascular complications.

Sex differences in CD8+ T cell responses during adaptive immunity

Biological sex is an important variable that influences the immune system's susceptibility to infectious and non-infectious diseases and their outcomes. Sex dimorphic features in innate and adaptive immune cells and their activities may help to explain sex differences in immune responses. T lymphocytes in the adaptive immune system are essential to providing protection against infectious and chronic inflammatory diseases. In this review, T cell responses are discussed with focus on the current knowledge of biological sex differences in CD8+ T cell mediated adaptive immune responses in infectious and chronic inflammatory diseases. Future directions aimed at investigating the molecular and cellular mechanisms underlying sex differences in diverse T cell responses will continue to underscore the significance of understanding sex differences in protective immunity at the cellular level, to induce appropriate T cell-based immune responses in infection, autoimmunity, and cancer. This article is categorized under: Immune System Diseases > Molecular and Cellular Physiology Infectious Diseases > Molecular and Cellular Physiology.

Mitochondrial Transplantation Promotes Protective Effector and Memory CD4+ T Cell Response During Mycobacterium Tuberculosis Infection and Diminishes Exhaustion and Senescence in Elderly CD4+ T cells

Tuberculosis (TB), caused by Mycobacterium tuberculosis (M.tb), is a major global health concern, particularly affecting those with weakened immune systems, including the elderly. CD4+ T cell response is crucial for immunity against M.tb, but chronic infections and aging can lead to T cell exhaustion and senescence, worsening TB disease. Mitochondrial dysfunction, prevalent in aging and chronic diseases, disrupts cellular metabolism, increases oxidative stress, and impairs T-cell functions. This study investigates the effect of mitochondrial transplantation (mito-transfer) on CD4+ T cell differentiation and function in aged mouse models and human CD4+ T cells from elderly individuals. Mito-transfer in naïve CD4+ T cells is found to promote protective effector and memory T cell generation during M.tb infection in mice. Additionally, it improves elderly human T cell function by increasing mitochondrial mass and altering cytokine production, thereby reducing markers of exhaustion and senescence. These findings suggest mito-transfer as a novel approach to enhance aged CD4+ T cell functionality, potentially benefiting immune responses in the elderly and chronic TB patients. This has broader implications for diseases where mitochondrial dysfunction contributes to T-cell exhaustion and senescence.

From MASLD to HCC: What's in the middle?

Metabolic dysfunction associated steatotic liver disease (MASLD) is a progressive pathological condition characterized by the accumulation of triglycerides within hepatocytes that causes histological changes, which, in the long run, might compromise liver functional capacities. MASLD predisposes to metabolic dysfunction-associated steatohepatitis (MASH), in which the persistence of inflammatory reactions perpetuates tissue injury and induces alterations of the extracellular matrix, leading to liver fibrosis and cirrhosis. Furthermore, these processes are also fertile ground for the development of hepatocellular carcinoma (HCC). In this latter respect, growing evidence suggests that chronic inflammation not only acts as the primary stimulus for hepatocellular malignant transformation, cell proliferation and cancer cell progression but also reshapes the immune landscape, inducing immune system exhaustion and favoring the loss of cancer immune surveillance. Therefore, a thorough understanding of the cellular and molecular mechanisms orchestrating hepatic inflammatory responses may open the way for fine-tuning therapeutic interventions that could, from one side, counteract MASLD progression and, on the other one, effectively treat HCCs.

Could Vaccination against COVID-19 Trigger Immune-Mediated Inflammatory Diseases?

Exacerbations and new onset of immune-mediated inflammatory diseases, such as psoriasis and hidradenitis suppurativa, have been reported following COVID-19 vaccination. In patients with hidradenitis suppurativa, recent studies have shown that those who received mRNA vaccines were 3.5 times as likely to develop flares following vaccination compared to patients who received non-mRNA vaccines, indicating that mRNA COVID-19 vaccines are associated with hidradenitis suppurativa flares. Similar findings have been found in other studies evaluating the association between COVID-19 vaccines and other immune-mediated inflammatory diseases such as psoriasis, atopic dermatitis, lichen planus, and alopecia areata. However, further research is warranted in larger populations to validate these findings.

The gut-immune axis during hypertension and cardiovascular diseases

The gut-immune axis is a relatively novel phenomenon that provides mechanistic links between the gut microbiome and the immune system. A growing body of evidence supports it is key in how the gut microbiome contributes to several diseases, including hypertension and cardiovascular diseases (CVDs). Evidence over the past decade supports a causal link of the gut microbiome in hypertension and its complications, including myocardial infarction, atherosclerosis, heart failure, and stroke. Perturbations in gut homeostasis such as dysbiosis (i.e., alterations in gut microbial composition) may trigger immune responses that lead to chronic low-grade inflammation and, ultimately, the development and progression of these conditions. This is unsurprising, as the gut harbors one of the largest numbers of immune cells in the body, yet is a phenomenon not entirely understood in the context of cardiometabolic disorders. In this review, we discuss the role of the gut microbiome, the immune system, and inflammation in the context of hypertension and CVD, and consolidate current evidence of this complex interplay, whilst highlighting gaps in the literature. We focus on diet as one of the major modulators of the gut microbiota, and explain key microbial-derived metabolites (e.g., short-chain fatty acids, trimethylamine N-oxide) as potential mediators of the communication between the gut and peripheral organs such as the heart, arteries, kidneys, and the brain via the immune system. Finally, we explore the dual role of both the gut microbiome and the immune system, and how they work together to not only contribute, but also mitigate hypertension and CVD.

Hypothesis: hematogenous metastatic cancer cells of solid tumors may disguise themselves as memory macrophages for metastasis

German pathologist Otto Aichel suggested, a century ago, that the cancer cell acquired its metastatic property from a leukocyte via cell-cell fusion. Since then, several revised versions of this theory have been proposed. Most of the proposals attribute the generation of the metastatic cancer cell to the fusion between a primary cancer cell and a macrophage. However, these theories have not addressed several issues, such as dormancy and stem cell-like self-renewal, of the metastatic cancer cell. On the other hand, recent studies have found that, like T- and B-/plasma cells, macrophages can also be categorized into naïve, effector, and memory/trained macrophages. As a memory/trained macrophage can enter dormancy/quiescence, be awakened from the dormancy/quiescence by acquainted primers, and re-populate via stem cell-like self-renewal, we, therefore, further specify that the macrophage fusing with the cancer cell and contributing to metastasis, belongs with the memory/trained macrophage, not other subtypes of macrophages. The current theory can explain many puzzling clinical features of cancer, including the paradoxal effects (recurrence vs. regression) of microbes on tumors, "spontaneous" and Coley's toxin-induced tumor regression, anticancer activities of β-blockers and anti-inflammatory/anti-immune/antibiotic drugs, oncotaxis, surgery- and trauma-promoted metastasis, and impact of microbiota on tumors. Potential therapeutic strategies, such as Coley's toxin-like preparations, are proposed. This is the last article of our trilogy on carcinogenesis theories.

IL-27 promotes pathogenic T cells in a mouse model of Sjögren's disease

Sjögren's disease (SjD) is a chronic autoimmune disease characterized by focal lymphocytic inflammation in lacrimal and salivary glands. We recently identified IL-27 as a requisite signal for the spontaneous SjD-like manifestations in nonobese diabetic (NOD) mice. Here, we define T cell-intrinsic effects of IL-27 in lacrimal gland disease in NOD mice. IL-27 receptor was required by both CD4 T effector (Te) cells and CD8 T cells to mediate focal inflammation. Intrinsic IL-27 signaling was associated with PD-1 and ICOS expressing T follicular helper (Tfh)-like CD4 Te cells within lacrimal glands, including subsets defined by CD73 or CD39 expression. CD8 T cells capable of IL-27 signaling also expressed PD-1 with subsets expressing ICOS and CD73 demonstrating a T follicular cytotoxic (Tfc)-like cell phenotype and others expressing a CD39hi exhausted-like phenotype. These findings suggest IL-27 is a key early signal driving a follicular-type response in lacrimal gland inflammation in NOD mice.

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: the biology of a neglected disease

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a chronic, debilitating disease characterised by a wide range of symptoms that severely impact all aspects of life. Despite its significant prevalence, ME/CFS remains one of the most understudied and misunderstood conditions in modern medicine. ME/CFS lacks standardised diagnostic criteria owing to variations in both inclusion and exclusion criteria across different diagnostic guidelines, and furthermore, there are currently no effective treatments available. Moving beyond the traditional fragmented perspectives that have limited our understanding and management of the disease, our analysis of current information on ME/CFS represents a significant paradigm shift by synthesising the disease's multifactorial origins into a cohesive model. We discuss how ME/CFS emerges from an intricate web of genetic vulnerabilities and environmental triggers, notably viral infections, leading to a complex series of pathological responses including immune dysregulation, chronic inflammation, gut dysbiosis, and metabolic disturbances. This comprehensive model not only advances our understanding of ME/CFS's pathophysiology but also opens new avenues for research and potential therapeutic strategies. By integrating these disparate elements, our work emphasises the necessity of a holistic approach to diagnosing, researching, and treating ME/CFS, urging the scientific community to reconsider the disease's complexity and the multifaceted approach required for its study and management.

Machine learning combined with single-cell analysis reveals predictive capacity and immunotherapy response of T cell exhaustion-associated lncRNAs in uterine corpus endometrial carcinoma

BACKGROUND

The exhaustion of T-cells is a primary factor contributing to immune dysfunction in cancer. Long non-coding RNAs (lncRNAs) play a significant role in the advancement, survival, and treatment of Uterine Corpus Endometrial Carcinoma (UCEC). Nevertheless, there has been no investigation into the involvement of lncRNAs associated with T-cell exhaustion (TEXLs) in UCEC. The goal of this work is to establish predictive models for TEXLs in UCEC and study their related immune features.

METHODS

Using transcriptome and single-cell sequencing data from The Cancer Genome Atlas and Gene Expression Omnibus databases, we employed co-expression analysis and univariate Cox regression to identify prognostic-associated TEXLs (pTEXLs). The prognostic model was developed using the Least Absolute Contraction and Selection Operator. The immunotherapy characteristics of the prognostic model risk score were studied. Then molecular subgroups were identified through non-negative Matrix Factorization based on pTEXLs. The identification of co-expressed genes was done using a weighted correlation network analysis. Subsequently, a diagnostic model for UCEC was created. In-depth investigations, both in vitro and in vivo, were carried out to elucidate the molecular mechanism of the key gene within the diagnostic model.

RESULTS

Receiver operating characteristic curve, calibration curve, and decision curve analysis proved the validity of the predictive models established according to pTEXLs. The subgroup with lower risk scores in the prognostic model has better responses to blocking immune checkpoint therapy. Single-cell analysis suggests that the expression level of MIEN1 is relatively high in immune cells among diagnostic genes. Furthermore, the targeted suppression of MIEN1 via sh-MIEN1 diminishes the proliferative, migratory, and invasive capacities of UCEC cells, potentially associated with CD8+ T cell exhaustion.

CONCLUSIONS

The association between TEXLs and UCEC was methodically elucidated by our investigation. A stable pTEXLs risk prediction model and a diagnosis model for UCEC were also established.

Repeated immunization with ATRA-containing liposomal adjuvant transdifferentiates Th17 cells to a Tr1-like phenotype

In many autoimmune diseases, autoantigen-specific Th17 cells play a pivotal role in disease pathogenesis. Th17 cells can transdifferentiate into other T cell subsets in inflammatory conditions, however, there have been no attempts to target Th17 cell plasticity using vaccines. We investigated if autoantigen-specific Th17 cells could be specifically targeted using a therapeutic vaccine approach, where antigen was formulated in all-trans retinoic acid (ATRA)-containing liposomes, permitting co-delivery of antigen and ATRA to the same target cell. Whilst ATRA was previously found to broadly reduce Th17 responses, we found that antigen formulated in ATRA-containing cationic liposomes only inhibited Th17 cells in an antigen-specific manner and not when combined with an irrelevant antigen. Furthermore, this approach shifted existing Th17 cells away from IL-17A expression and transcriptomic analysis of sorted Th17 lineage cells from IL-17 fate reporter mice revealed a shift of antigen-specific Th17 cells to exTh17 cells, expressing functional markers associated with T cell regulation and tolerance. In the experimental autoimmune encephalomyelitis (EAE) mouse model of MS, vaccination with myelin-specific (MOG) antigen in ATRA-containing liposomes reduced Th17 responses and alleviated disease. This highlights the potential of therapeutic vaccination for changing the phenotype of existing Th17 cells in the context of immune mediated diseases.

Sporadic Inclusion Body Myositis at the Crossroads between Muscle Degeneration, Inflammation, and Aging

Sporadic inclusion body myositis (sIBM) is the most common muscle disease of older people and is clinically characterized by slowly progressive asymmetrical muscle weakness, predominantly affecting the quadriceps, deep finger flexors, and foot extensors. At present, there are no enduring treatments for this relentless disease that eventually leads to severe disability and wheelchair dependency. Although sIBM is considered a rare muscle disorder, its prevalence is certainly higher as the disease is often undiagnosed or misdiagnosed. The histopathological phenotype of sIBM muscle biopsy includes muscle fiber degeneration and endomysial lymphocytic infiltrates that mainly consist of cytotoxic CD8+ T cells surrounding nonnecrotic muscle fibers expressing MHCI. Muscle fiber degeneration is characterized by vacuolization and the accumulation of congophilic misfolded multi-protein aggregates, mainly in their non-vacuolated cytoplasm. Many players have been identified in sIBM pathogenesis, including environmental factors, autoimmunity, abnormalities of protein transcription and processing, the accumulation of several toxic proteins, the impairment of autophagy and the ubiquitin-proteasome system, oxidative and nitrative stress, endoplasmic reticulum stress, myonuclear degeneration, and mitochondrial dysfunction. Aging has also been proposed as a contributor to the disease. However, the interplay between these processes and the primary event that leads to the coexistence of autoimmune and degenerative changes is still under debate. Here, we outline our current understanding of disease pathogenesis, focusing on degenerative mechanisms, and discuss the possible involvement of aging.

Serological Antibodies against Kidney, Liver, and Spleen Membrane Antigens as Potential Biomarkers in Patients with Immune Disorders

Immune disorders arise from complex genetic and environmental factors, which lead to dysregulation at the cellular and inflammatory levels and cause tissue damage. Recent research highlights the crucial role of reactive antibodies in autoimmune diseases and graft rejection, but their complex determination poses challenges for clinical use. Therefore, our study aimed to ascertain whether the presence of reactive antibodies against membrane antigens in tissues from both animal models and humans could serve as biomarkers in patients with autoimmune disorders. To address this issue, we examined the binding profile of serological antibodies against a diverse panel of cell membranes from the spleen, liver, and kidney tissues of monkeys, rats, and humans. After developing the cell membrane microarrays, human sera were immunologically assayed. The study was first conducted on sera from two groups, healthy subjects and patients with inflammatory and autoimmune disorders, and then optimized for kidney transplant patient sera. A significant increase in antibody reactivity against specific monkey kidney and spleen membranes was observed in the serum of patients with lupus nephritis, while kidney transplant patients showed a significant enhancement against human tissues and human embryonic kidney 293 cells. These results show the potential importance for clinical and basic research purposes of studying the presence of specific IgG against membrane antigens in patients' serum as potential biomarkers of immune disorders. However, it is important to note that these results need to be verified in further studies with a larger sample size to confirm their relevance.

Chronic inflammation and cancer; the two sides of a coin

The correlation between chronic inflammation and cancer was initially identified in the 19th century. Biomolecules like interleukins, chemokines, tumor necrosis factors, growth factors, and adhesion molecules, which regulate inflammation, are recognized contributors to neoplastic transformation through various mechanisms, including oncogenic mutations, resistance to apoptosis, and adaptive responses like angiogenesis. This review aims to establish connections between the intricate and complex mechanisms of chronic inflammation and cancer. We illuminate implicit signaling mechanisms that drive the association between chronic inflammation and the initiation/progression of cancer, exploring potential impacts on other diseases. Additionally, we discuss the modalities of currently available therapeutic options for chronic inflammation and cancer, emphasizing the dual nature of such therapies. A thorough understanding of the molecular basis of chronic inflammation is crucial for developing novel approaches in the prevention and treatment of cancer.

Lymphocyte-activation gene 3 (LAG-3) as a promising immune checkpoint in cancer immunotherapy: From biology to the clinic

In recent years, there have been notable advancements in the field of cancer immunotherapy, namely in the area of immune checkpoint inhibition. The Lymphocyte-activation gene 3 (LAG-3) has garnered attention as a potentially valuable focus of study in this particular field. The present study examines the biological aspects of LAG-3, its clinical consequences, and the potential therapeutic opportunities associated with its modulation. LAG-3, similar to CD4, has a regulatory role in modulating the immune system. The upregulation of this protein inside the neoplastic milieu hampers the immune system's ability to mount an effective response, hence enabling the evasion of cancer cells from immune surveillance. The LAG-3 protein interacts with ligands, inhibiting cytotoxic immune cells such as CD8+ T cells and NK cells. The potential of LAG-3 inhibitors presents intriguing prospects. Integrating these medicines with established treatments like PD-1/PD-L1 or CTLA-4 inhibitors can broaden the range of available therapy choices and address resistance issues. The advent of personalized therapy is imminent, as evidenced by the utilization of predictive biomarkers such as LAG-3 expression to inform individualized therapeutic approaches. Additionally, inhibitors of LAG-3 exhibit promise in addressing immunological depletion and resistance by revitalizing T cells and producing durable immune responses. The realization of LAG-3's promise necessitates global collaboration and equal access. Multinational trials are expected to ascertain the efficacy of the intervention in various patient groups.

Mitochondrial Transplantation promotes protective effector and memory CD4+ T cell response during Mycobacterium tuberculosis infection and diminishes exhaustion and senescence in elderly CD4+ T cells

Tuberculosis (TB), caused by the bacterium Mycobacterium tuberculosis (M.tb), remains a significant health concern worldwide, especially in populations with weakened or compromised immune systems, such as the elderly. Proper adaptive immune function, particularly a CD4+ T cell response, is central to host immunity against M.tb. Chronic infections, such as M.tb, as well as aging promote T cell exhaustion and senescence, which can impair immune control and promote progression to TB disease. Mitochondrial dysfunction contributes to T cell dysfunction, both in aging and chronic infections and diseases. Mitochondrial perturbations can disrupt cellular metabolism, enhance oxidative stress, and impair T-cell signaling and effector functions. This study examined the impact of mitochondrial transplantation (mito-transfer) on CD4+ T cell differentiation and function using aged mouse models and human CD4+ T cells from elderly individuals. Our study revealed that mito-transfer in naïve CD4+ T cells promoted the generation of protective effector and memory CD4+ T cells during M.tb infection in mice. Further, mito-transfer enhanced the function of elderly human T cells by increasing their mitochondrial mass and modulating cytokine production, which in turn reduced exhaustion and senescence cell markers. Our results suggest that mito-transfer could be a novel strategy to reestablish aged CD4+ T cell function, potentially improving immune responses in the elderly and chronic TB patients, with a broader implication for other diseases where mitochondrial dysfunction is linked to T cell exhaustion and senescence.

CD4 T-cell aging exacerbates neuroinflammation in a late-onset mouse model of amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is an adult-onset progressive neurodegenerative disorder characterized by the loss of upper and lower motor neurons in the brain and spinal cord. Accumulating evidence suggests that ALS is not solely a neuronal cell- or brain tissue-autonomous disease and that neuroinflammation plays a key role in disease progression. Furthermore, whereas both CD4 and CD8 T cells were observed in spinal cords of ALS patients and in mouse models of the disease, their role in the neuroinflammatory process, especially considering their functional changes with age, is not fully explored. In this study, we revealed the structure of the CD4 T-cell compartment during disease progression of early-onset SOD1G93A and late-onset SOD1G37R mouse models of ALS. We show age-related changes in the CD4 T-cell subset organization between these mutant SOD1 mouse models towards increased frequency of effector T cells in spleens of SOD1G37R mice and robust infiltration of CD4 T cells expressing activation markers and the checkpoint molecule PD1 into the spinal cord. The frequency of infiltrating CD4 T cells correlated with the frequency of infiltrating CD8 T cells which displayed a more exhausted phenotype. Moreover, RNA-Seq and immunohistochemistry analyses of spinal cords from SOD1G37R mice with early clinical symptoms demonstrated immunological trajectories reminiscent of a neurotoxic inflammatory response which involved proinflammatory T cells and antigen presentation related pathways. Overall, our findings suggest that age-related changes of the CD4 T cell landscape is indicative of a chronic inflammatory response, which aggravates the disease process and can be therapeutically targeted.

Immunogenicity of Intradermal Versus Intramuscular BNT162b2 COVID-19 Booster Vaccine in Patients with Immune-Mediated Dermatologic Diseases: A Non-Inferiority Randomized Controlled Trial

The intradermal route has emerged as a dose-sparing alternative during the coronavirus disease 2019 (COVID-19) pandemic. Despite its efficacy in healthy populations, its immunogenicity has not been tested in immune-mediated dermatologic disease (IMDD) patients. This assessor-blinded, randomized-controlled, non-inferiority trial recruited patients with two representative IMDDs (i.e., psoriasis and autoimmune bullous diseases) to vaccinate with fractionated-dose intradermal (fID) or standard intramuscular (sIM) BNT162b2 vaccines as a fourth booster dose under block randomization stratified by age, sex, and their skin diseases. Post-vaccination SARS-CoV-2-specific IgG and interferon-γ responses measured 4 and 12 weeks post-intervention were serological surrogates used for demonstrating treatment effects. Mean differences in log-normalized outcome estimates were calculated with multivariable linear regression adjusting for their baseline values, systemic immunosuppressants used, and prior COVID-19 vaccination history. The non-inferiority margin was set for fID to retain >80% immunogenicity of sIM. With 109 participants included, 53 received fID (all entered an intention-to-treat analysis). The fID demonstrated non-inferiority to sIM in humoral (mean outcome estimates of sIM: 3.3, ΔfID-sIM [mean, 95%CI]: -0.1, -0.3 to 0.0) and cellular (mean outcome estimates of sIM: 3.2, ΔfID-sIM [mean, 95%CI]: 0.1, -0.2 to 0.3) immunogenicity outcomes. Two psoriasis patients from the fID arm (3.8%) developed injection-site Koebner's phenomenon. Fewer fID recipients experienced post-vaccination fever (fID vs. sIM: 1.9% vs. 12.5%, p = 0.027). The overall incidence of disease flare-ups was low without a statistically significant difference between groups. The intradermal BNT162b2 vaccine is a viable booster option for IMDD patients troubled by post-vaccination fever; its role in mitigating the risk of flare-ups remains unclear.

Immune-related adverse events with bispecific T-cell engager therapy targeting B-cell maturation antigen

Not available.

Single-cell profiling identifies distinct hormonal, immunologic, and inflammatory signatures of endometriosis-constituting cells

Endometriosis consists of ectopic endometrial epithelial cells (EEECs) and ectopic endometrial stromal cells (EESCs) mixed with heterogeneous stromal cells. To address how endometriosis-constituting cells are different from normal endometrium and among endometriosis subtypes and how their molecular signatures are related to phenotypic manifestations, we analyzed ovarian endometrial cyst (OEC), superficial peritoneal endometriosis (SPE), and deep infiltrating endometriosis (DIE) from 12 patients using single-cell RNA-sequencing (scRNA-seq). We identified 11 cell clusters, including EEEC, EESC, fibroblasts, inflammatory/immune, endothelial, mesothelial, and Schwann cells. For hormonal signatures, EESCs, but not EEECs, showed high estrogen signatures (estrogen response scores and HOXA downregulation) and low progesterone signatures (DKK1 downregulation) compared to normal endometrium. In EEECs, we found MUC5B+ TFF3low cells enriched in endometriosis. In lymphoid cells, evidence for both immune activation (high cytotoxicity in NK) and exhaustion (high checkpoint genes in NKT and cytotoxic T) was identified in endometriosis. Signatures and subpopulations of macrophages were remarkably different among endometriosis subtypes with increased monocyte-derived macrophages and IL1B expression in DIE. The scRNA-seq predicted NRG1 (macrophage)-ERBB3 (Schwann cell) interaction in endometriosis, expressions of which were validated by immunohistochemistry. Myofibroblast subpopulations differed according to the location (OECs from fibroblasts and SPE/DIEs from mesothelial cells and fibroblasts). Endometriosis endothelial cells displayed proinflammation, angiogenesis, and leaky permeability signatures that were enhanced in DIE. Collectively, our study revealed that (1) many cell types-endometrial, lymphoid, macrophage, fibroblast, and endothelial cells-are altered in endometriosis; (2) endometriosis cells show estrogen responsiveness, immunologic cytotoxicity and exhaustion, and proinflammation signatures that are different in endometriosis subtypes; and (3) novel endometriosis-specific findings of MUC5B+ EEECs, mesothelial cell-derived myofibroblasts, and NRG1-ERBB3 interaction may underlie the pathogenesis of endometriosis. Our results may help extend pathologic insights, dissect aggressive diseases, and discover therapeutic targets in endometriosis. © 2023 The Pathological Society of Great Britain and Ireland.

Immunosenescence and Immune Exhaustion Are Associated with Levels of Protein-Bound Uremic Toxins in Patients on Hemodialysis

BACKGROUND

The accumulation of protein-bound uremic toxins (PBUTs) in chronic kidney disease may affect patients' immune status. The aim of the study was to evaluate their potential impacts on lymphocyte alterations in patients on hemodialysis (HD).

METHODS

The plasma levels of PBUTs were assessed in 54 patients on HD and 31 healthy individuals, using ultra-performance liquid chromatography. The results correlated with the senescent and exhausted status of lymphocytes, based on certain surface molecules, analyzed by flow cytometry.

RESULTS

The plasma levels of PBUTs were significantly increased in the patients on HD compared with the healthy controls. The patients with residual kidney function had reduced hippuric acid (HA) levels, total (p = 0.03) and free (p = 0.04), and free IxS levels (p = 0.02). The total and free HA levels correlated negatively with less differentiated subpopulations, CD4+CD45RA+CD31+ (p = 0.037 and p = 0.027), CD8+CD28+CD57- (p = 0.01, p = 0.01), and naïve B cells (CD19+IgD+CD27-) (p = 0.04, p = 0.03). Both the total and the free pCS levels correlated positively with exhausted CD4 cells, p = 0.02 and p = 0.01, respectively. A multivariate analysis showed that IxS and age were the main independent parameters implicated in the reduction intotal CD4 and B lymphocytes and their naïve and early differentiated subsets.

CONCLUSIONS

Increased PBUTs levels are associated with immune disturbances of patients on HD, HA, and IxS in the immunosenescent and pCS in the immunoexhaustion alterations.

Chronic allergic asthma induces T-cell exhaustion and impairs virus clearance in mice

BACKGROUND

Allergic asthma, one of the most common types of asthma, is thought to be highly susceptible to respiratory viral infections; however, its pathological mechanism needs to be elucidated. Recent studies have found impaired T-cell function in asthmatic mice. Therefore, we aimed to investigate the way by which asthma induction affects T-cell exhaustion in the lungs and assess the relationship between T-cell exhaustion and influenza viral infection.

METHODS

Chronic allergic asthma mice were induced by intranasal injection of ovalbumin for 6 weeks and asthmatic features and T cell populations in lung or airway were assessed. To determine the influenza virus susceptibility, control and asthma mice were challenged with the human influenza virus strain A/Puerto Rico/8/1934 H1N1 and evaluated the survival rate, lung damage, and virus titer.

RESULTS

Six weeks of OVA sensitization and challenge successfully induced chronic allergic asthma in a mouse model showing significant increase of sera IgE level and broncho-pathological features. A significant decrease in interferon-γ-producing T-cell populations and an increase in exhausted T-cell populations in the lungs of OVA-induced asthmatic mice were observed. Asthmatic mice were more susceptible to influenza virus infection than control mice showing lower survival rate and higher virus titer in lung, and a positive correlation existed between T-cell exhaustion in the lung and virus titer.

CONCLUSIONS

Asthma induction in mice results in the exhaustion of T-cell immunity, which may contribute to the defective capacity of viral protection. This study demonstrates a correlation between asthma conditions and viral susceptibility by investigating the functional characteristics of T-cells in asthma. Our results provide insights into the development of strategies to overcome the dangers of respiratory viral disease in patients with asthma.

T-cell dysfunction in natural killer/T-cell lymphoma

Natural killer/T-cell lymphoma (NKTCL) is an incurable aggressive T-cell lymphoma closely correlated with Epstein‒Barr virus (EBV) infection. Chronic and consistent viral infection induces T-cell exhaustion. Herein, we describe T-cell dysfunction in NKTCL patients for the first time. Peripheral blood mononuclear cells (PBMCs) from age-matched healthy donors (HDs) and NKTCL patients were collected, and lymphocyte distributions, multiple surface inhibitory receptors (IRs), effector cytokine production and cell proliferation were determined by flow cytometry. PBMCs from HDs were cocultured with NKTCL cell lines to verify the clinical findings. IR expression was further assessed in NKTCL tumor biopsies using multiplex immunohistochemistry (mIHC). NKTCL patients have higher frequencies than HDs of inhibitory T regulatory cells (Tregs) and myeloid-derived suppressor cells (MDSCs). T-cell distribution also varies between NKTCL patients and HDs. T cells from NKTCL patients demonstrated higher expression levels of multiple IRs than HDs. Meanwhile, T-cell proliferation and interferon-γ production was significantly reduced in NKTCL patients. More importantly, the number of EBV-specific cytotoxic cells was lower in NTKCL patients, and these cells demonstrated upregulation of multiple IRs and secreted fewer effector cytokines. Interestingly, NKTCL cells caused normal PBMCs to acquire T-cell exhaustion phenotypes and induced generation of Tregs and MDSCs. In line with ex vivo finding, mIHC results showed that CD8+ T cells from NKTCL tumor biopsies expressed much higher level of IRs compared with reactive lymphoid hyperplasia individuals. The immune microenvironment of NKTCL patients exhibited T-cell dysfunction and accumulation of inhibitory cell components, which may contribute to impaired antitumor immunity.

A Concerted Vision to Advance the Knowledge of Diabetes Mellitus Related to Immune Checkpoint Inhibitors

The rubric of immune-related (ir) diabetes mellitus (DM) (irDM) encompasses various hyperglycemic disorders related to immune checkpoint inhibitors (ICPis). Beyond sharing similarities with conventional DM, irDM is a distinct, yet important, entity. The present narrative review provides a comprehensive overview of the literature regarding irDM published in major databases from January 2018 until January 2023. Initially considered rare, irDM is increasingly being reported. To advance the knowledge of irDM, the present review suggests a concerted vision comprising two intertwined aspects: a scientific-centered and a patient-centered view. The scientific-centered aspect addresses the pathophysiology of irDM, integrating: (i) ICPi-induced pancreatic islet autoimmunity in genetically predisposed patients; (ii) altered gut microbiome; (iii) involvement of exocrine pancreas; (iv) immune-related acquired generalized lipodystrophy. The patient-centered aspect is both nurtured by and nurturing the four pillars of the scientific-centered aspect: awareness, diagnosis, treatment, and monitoring of irDM. The path forward is a multidisciplinary initiative towards: (i) improved characterization of the epidemiological, clinical, and immunological profile of irDM; (ii) standardization of reporting, management, and surveillance protocols for irDM leveraging global registries; (iii) patient stratification according to personalized risk for irDM; (iv) new treatments for irDM; and (v) uncoupling ICPi efficacy from immunotoxicity.

Overexpression of TREM1 is Associated with the Immune-Suppressive Microenvironment and Unfavorable Prognosis in Pan-Cancer

Background

Triggering receptors expressed by myeloid cells-1 (TREM1) is a receptor belonging to the immunoglobulin superfamily and plays an important role in pro-inflammation in acute and chronic inflammatory disorders. However, the understanding of the immunomodulatory roles of TREM1 in the tumor microenvironment remains incomplete.

Methods

The expression patterns of TREM1 mRNA in tumors and adjacent normal tissues were compared by analyzing data obtained from the Genotype-Tissue Expression and The Cancer Genome Atlas datasets. Survival analysis was performed to determine the prognostic value of TREM1. Functional enrichment analysis was applied to decipher the discrepancy in biological processes between high- and low-TREM1 groups across various cancers. The correlation between TREM1 and immune cell infiltration determined by using multiple algorithms was evaluated with the Pearson method. Four independent immunotherapy cohorts were adopted to validate the role of TREM1 as a biomarker.

Results

TREM1 was elevated in most cancers as verified with clinical samples. Overexpression of TREM1 was linked with undesirable prognosis in patients. Further analysis revealed that TREM1 was positively correlated with immune response, pro-tumor pathways, and myeloid cell infiltration, while being negatively correlated with CD8⁺ T cell (including infiltration level and biological processes). Concordantly, tumors with high TREM1 levels were more resistant to immunotherapy. Through connective map analysis, therapeutically potential compounds like tozasertib and TPCA-1 were identified, which can be used synergistically with immunotherapy to improve the poor prognosis of patients with high TREM1 levels.

Conclusion

Through a systematic and comprehensive pan-cancer analysis, we demonstrated that overexpression of TREM1 in tumors correlated closely with unfavorable outcome, infiltration of immune-suppressive cells, and immune regulation, which highlights its potential use as a tumor prognostic biomarker and a novel target for immunotherapy.