Exhaustion of CD39-Expressing CD8+ T Cells in Crohn's Disease Is Linked to Clinical Outcome

Accelerated biological aging and risk of inflammatory bowel disease: A prospective study from 401,013 participants

OBJECTIVES

Relationship between biological aging and inflammatory bowel disease (IBD) remains unclear. We aimed to explore the associations of biological age and genetic predisposition with IBD and the predictive ability.

METHODS

Biological age and genetic predisposition were measured by PhenoAge and the polygenic risk score (PRS), respectively. The hazard ratio (HR) and 95% confidence interval (CI) of PhenoAge and combined PRS for Crohn's disease (CD) and ulcerative colitis (UC) were evaluated by Cox proportional hazards models. Additive interactions were examined to evaluate the joint effect. C statistic was employed to assess the predictive ability.

RESULTS

During the follow-up period of 5,320,311 person-years of 401,013 participants, 2467 patients with UC and 1262 patients with CD were observed. PhenoAge showed a significant association with an increased risk of incident IBD. Each standard deviation of PhenoAge acceleration correlated with a 38% (95% CI: 34%-41%), 35% (95% CI: 30%-38%), and 46% (95% CI: 41%-51%) increased risk of IBD, UC, and CD, respectively. Joint effects and additive interactions were noted between PhenoAge and the PRS. Individuals with a high PRS and the highest PhenoAge acceleration had the highest risk for UC (HR: 9.16, 95% CI: 7.08-11.85) and CD (7.72, 6.05-9.86), respectively. Incorporating PhenoAge and the PRS could enhance the accuracy of predicting IBD, with a highest C statistic of 0.71 for UC and 0.72 for CD.

CONCLUSION

Accelerated biological aging is associated with an increased risk of IBD, particularly in individuals with high genetic predisposition. Identifying individuals with accelerated biological aging has significant implications for reducing IBD risk.

Novel Insights into the Pathogenesis of Inflammatory Bowel Diseases

Inflammatory bowel diseases (IBDs), encompassing Crohn's disease and ulcerative colitis, are complex chronic disorders characterized by an intricate interplay between genetic predisposition, immune dysregulation, gut microbiota alterations, and environmental exposures. This review aims to synthesize recent advances in IBD pathogenesis, exploring key mechanisms and potential avenues for prevention and personalized therapy. A comprehensive literature search was conducted across major bibliographic databases, selecting the most recent and impactful studies on IBD pathogenesis. The review integrates findings from multi-omics analyses, single-cell transcriptomics, and longitudinal cohort studies, focusing on immune regulation, gut microbiota dynamics, and environmental factors influencing disease onset and progression. Immune dysregulation, including macrophage polarization (M1 vs. M2) and Th17 activation, emerges as a cornerstone of IBD pathogenesis. Dysbiosis, as a result of reduced alpha and beta diversity and overgrowth of harmful taxa, is one of the main contributing factors in causing inflammation in IBD. Environmental factors, including air and water pollutants, maternal smoking, and antibiotic exposure during pregnancy and infancy, significantly modulate IBD risk through epigenetic and microbiota-mediated mechanisms. While recent advances have supported the development of new therapeutic strategies, deeply understanding the complex dynamics of IBD pathogenesis remains challenging. Future efforts should aim to reduce the burden of disease with precise, personalized treatments and lower the incidence of IBD through early-life prevention and targeted interventions addressing modifiable risk factors.

α-Methyl-Tryptophan Inhibits SLC6A14 Expression and Exhibits Immunomodulatory Effects in Crohn's Disease

Introduction

Crohn's disease (CD) is a chronic inflammatory condition of the intestines with a rising global incidence. Traditional diagnostic and therapeutic methods have limitations, necessitating the exploration of more effective strategies.

Methods

In this study, we employed the Gene Expression Omnibus database to identify genes that are differentially expressed in CD. RT-PCR and immunohistochemical analysis were used to SLC6A14 RNA and protein expression in the colons of CD mice and CD tissues from patients. The mouse model of CD was induced by dextran sodium sulfate (DSS). Infiltrating immune cells in mouse model were screened by flow cytometry.

Results

We discovered that SLC6A14 is significantly overexpressed in CD samples, and its expression is positively correlated with the degree of infiltration by CD4+ and CD8+ T cells. The elevated levels of SLC6A14 RNA and protein were confirmed in clinical CD tissues. The SLC6A14 inhibitor α-methyl-tryptophan (α-MT) significantly decreased the expression of SLC6A14 RNA and protein in the colons of CD mice. The α-MT treatment group also exhibited reduced levels of cytokines involved in T cell differentiation (IFN-γ and TNF-α) and the expression of immune cell surface markers CXCR-3 and LAG-3. Flow cytometry analysis revealed a significant increase in the infiltration of CD4+ and CD8+ T cells in the DSS-treated group compared to the control group. Conversely, the α-MT treatment group showed a significant reduction in CD4+ and CD8+ T cell infiltration and the restoration of intestinal parameters in CD mice. These findings underscore the role of SLC6A14 in regulating intestinal immune cell infiltration during CD progression.

Discussion

Our findings suggest that SLC6A14 could serve as a potential diagnostic biomarker and therapeutic target for CD. Furthermore, α-MT offers a novel approach for the clinical diagnosis and treatment of CD by targeting SLC6A14 for therapeutic intervention.

Adiponectin and HMW Oligomers in Relation to Inflammatory Markers in Crohn's Disease Patients

Background/Objectives: Crohn's disease (CD), a chronic inflammatory gastrointestinal illness, is the result of genetics and environmental factors. Adipose tissue has recently been found to play a significant role in CD. Methods: here, we examined the relationship between adiponectin, HMW oligomers, and CD in 92 patients. Results: first, we verified that the patients' therapies had no influence on the nutritional and biochemical variables. Correlation analysis between HMW adiponectin and nutritional parameters found no relationship; therefore, we investigated its relationship with CD severity and inflammatory markers. Based on adiponectin, we divided patients into tertiles and found that CDAI was lowest in the second and third tertile [I: <19.3 (n = 31); II: 19.3-22.2 (n = 31); III: >22.2 (n = 30)]. Furthermore, IL-6 and CRP were higher in the second and third tertile, while lymphocytes were lower in the second and third tertile. Correlation analysis showed that both adiponectin and HMW oligomers were inversely related to lymphocytes and directly related to CRP. A ROC curve evidenced that patients carrying adiponectin values ≤ 19 performed well in predicting worse CDAI and lymphocyte values (AUCs: 0.826 and 0.806). Next, we divided CD patients into tertiles based on HMW adiponectin, finding that IL-6 was highest in the second and third tertile. Lymphocytes were lowest in the third tertile while CRP values were substantially higher. Conclusions: altogether, these data suggest a biological role for adiponectin and HMW oligomers in CD severity and inflammatory status. However, the molecular effects related to adiponectin in CD remain unclear and further studies are needed to clarify its applicability as a biomarker.

Nitrogen-Rich Molybdenum Nitride with Intrinsic CD39 Nucleotidase Activity

CD39 is one of the important nucleotidases to adjust extracellular adenosine triphosphate (ATP) and adenosine diphosphate (ADP) concentration. However, the enzyme mimics to simulate the activity of CD39 still remains to be explored. Herein nitrogen-rich molybdenum nitride (Mo5N6) nanosheets are explored to possess CD39-like activity, which are able to catalyze the hydrolysis of the high-energy phosphate bonds (HEPBs) in ATP and ADP but not the common phosphate bonds in adenosine monophosphate (AMP). The catalytic hydrolysis of the phosphate bond over Mo5N6-700 nanosheets is first investigated using para-nitrophenyl phosphate as the model substrate and then the CD39-like activity is further explored and verified by 31p NMR spectroscopy. Mo4+ on the surface of Mo5N6-700 nanosheets are the catalytic active sites. Using ATP as the model substrate, the Km and Vmax values of CD39-like activity at optimal pH 9.0 are 3.2 µmol L-1 and 18.5 µmol L-1 h-1, respectively. The CD39-like activity of Mo5N6-700 nanosheets enabled the down-regulation of intracellular ATP concentration to a larger degree for cancer cells than normal cells, which makes Mo5N6-700 nanosheets a potential therapeutic reagent for cancers.

Common diagnostic biomarkers and molecular mechanisms of Helicobacter pylori infection and inflammatory bowel disease

Background

Helicobacter pylori (H. pylori) may be present in the intestinal mucosa of patients with inflammatory bowel disease (IBD), which is a chronic inflammation of the gastrointestinal tract. The role of H. pylori in the pathogenesis of IBD remains unclear. In this study, bioinformatics techniques were used to investigate the correlation and co-pathogenic pathways between H. pylori and IBD.

Methods

The following matrix data were downloaded from the GEO database: H. pylori-associated gastritis, GSE233973 and GSE27411; and IBD, GSE3365 and GSE179285. Differential gene analysis was performed via the limma software package in the R environment. A protein-protein interaction (PPI) network of DEGs was constructed via the STRING database. Cytoscape software, through the CytoHubba plugin, filters the PPI subnetwork and identifies Hub genes. Validation of the Hub genes was performed in the validation set. Immune analysis was conducted via the CIBERSORT algorithm. Transcription factor interaction and small molecule drug analyses of the Hub genes were also performed.

Results

Using the GSE233973 and GSE3365 datasets, 151 differentially expressed genes (DEGs) were identified. GO enrichment analysis revealed involvement in leukocyte migration and chemotaxis, response to lipopolysaccharides, response to biostimulatory stimuli, and regulation of interleukin-8 (IL-8) production. Ten Hub genes (TLR4, IL10, CXCL8, IL1B, TLR2, CXCR2, CCL2, IL6, CCR1 and MMP-9) were identified via the PPI network and Cytoscape software. Enrichment analysis of the Hub genes focused on the lipopolysaccharide response, bacterial molecular response, biostimulatory response and leukocyte movement. Validation using the GSE27411 and GSE179285 datasets revealed that MMP-9 was significantly upregulated in both the H. pylori and IBD groups. The CIBERSORT algorithm revealed immune infiltration differences between the control and disease groups of IBD patients. Additionally, the CMap database identified the top 11 small molecule compounds across 10 cell types, including TPCA-1, AS-703026 and memantine, etc.

Conclusion

Our study revealed the co-pathogenic mechanism between H. pylori and IBD and identified 10 Hub genes related to cellular immune regulation and signal transduction. The expression of MMP-9 is significantly upregulated in both H. pylori infection and IBD. This study provides a new perspective for exploring the prevention and treatment of H. pylori infection and IBD.

Mucosal Single-Cell Profiling of Crohn's-Like Disease of the Pouch Reveals Unique Pathogenesis and Therapeutic Targets

BACKGROUND & AIMS

The pathophysiology of Crohn's-like disease of the pouch (CDP) in patients with a history of ulcerative colitis (UC) is unknown. We examined mucosal cells from patients with and without CDP using single-cell analyses.

METHODS

Endoscopic samples were collected from pouch body and prepouch ileum (pouch/ileum) of 50 patients with an ileal pouch-anal anastomosis. Single-cell RNA sequencing was performed on pouch/ileal tissues of patients with normal pouch/ileum and CDP. Mass cytometry was performed on mucosal immune cells from patients with UC with normal pouch/ileum, CDP, pouchitis, and those with familial adenomatous polyposis after pouch formation. Findings were independently validated using immunohistochemistry.

RESULTS

The cell populations/states in the pouch body differed from those in the prepouch ileum, likely secondary to increased microbial burden. Compared with the familial adenomatous polyposis pouch, the UC pouch was enriched in colitogenic immune cells even without inflammation. CDP was characterized by increases in T helper 17 cells, inflammatory fibroblasts, inflammatory monocytes, TREM1+ monocytes, clonal expansion of effector T cells, and overexpression of T helper 17 cells-inducing cytokine genes such as IL23, IL1B, and IL6 by mononuclear phagocytes. Ligand-receptor analysis further revealed a stromal-mononuclear phagocytes-lymphocyte circuit in CDP. Integrated analysis showed that up-regulated immune mediators in CDP were similar to those in CD and pouchitis, but not UC. Additionally, CDP pouch/ileum exhibited heightened endoplasmic reticulum stress across all major cell compartments.

CONCLUSIONS

CDP likely represents a distinct entity of inflammatory bowel disease with heightened endoplasmic reticulum stress in both immune and nonimmune cells, which may become a novel diagnostic biomarker and therapeutic target for CDP.

Beyond Suppression: Peripheral T Cell Responses to Vaccination in Inflammatory Bowel Disease Patients Undergoing Anti-Tumor-Necrosis-Factor Therapy

Alimentary tract inflammation in inflammatory bowel disease (IBD) is treated by systemically administered drugs that alter fundamental host immune responses. Biologics that target tumor necrosis factor (TNF) are first-line biologics in IBD, used widely for their effectiveness, steroid-sparing quality, and lower cost. While they enable a significant proportion of patients to achieve clinical remission, they carry an increased risk of infection and poor serological responses to vaccination. Conversely, our understanding of adaptive T cell responses in anti-TNF-treated IBD patients remains limited. The introduction of COVID-19 vaccines has prompted research that both challenges and refines our view on immunomodulatory therapy and its potential implications for immunity and protection. Here, we review these emergent findings, evaluate how they shape our understanding of vaccine-induced T cell responses in the context of anti-TNF therapy in IBD, and provide a perspective highlighting the need for a holistic evaluation of both cellular and humoral immunity in this population.

T-cell exhaustion-related genes in Graves' disease: a comprehensive genome mapping analysis

Background

T-cell exhaustion (Tex) can be beneficial in autoimmune diseases, but its role in Graves' disease (GD), an autoimmune disorder of the thyroid, remains unknown. This study investigated Tex-related gene expression in GD patients to discern the potential contributions of these genes to GD pathogenesis and immune regulation.

Methods

Through gene landscape analysis, a protein-protein interaction network of 40 Tex-related genes was constructed. mRNA expression levels were compared between GD patients and healthy control (HCs). Unsupervised clustering categorized GD cases into subtypes, revealing distinctions in gene expression, immune cell infiltration, and immune responses. Weighted gene co-expression network analysis and differential gene expression profiling identified potential therapeutic targets. RT-qPCR validation of candidate gene expression was performed using blood samples from 112 GD patients. Correlations between Tex-related gene expression and clinical indicators were analyzed.

Results

Extensive Tex-related gene interactions were observed, with six genes displaying aberrant expression in GD patients. This was associated with atypical immune cell infiltration and regulation. Cluster analysis delineated two GD subtypes, revealing notable variations in gene expression and immune responses. Screening efforts identified diverse drug candidates for GD treatment. The Tex-related gene CBL was identified for further validation and showed reduced mRNA expression in GD patients, especially in cases of relapse. CBL mRNA expression was significantly lower in patients with moderate-to-severe thyroid enlargement than in those without such enlargement. Additionally, CBL mRNA expression was negatively correlated with the disease-specific indicator thyrotropin receptor antibodies.

Conclusion

Tex-related genes modulate GD pathogenesis, and their grouping aids subtype differentiation and exploration of therapeutic targets. CBL represents a potential marker for GD recurrence.

Challenges in IBD Research 2024: Precision Medicine

Precision medicine is part of 5 focus areas of the Challenges in IBD Research 2024 research document, which also includes preclinical human IBD mechanisms, environmental triggers, novel technologies, and pragmatic clinical research. Building on Challenges in IBD Research 2019, the current Challenges aims to provide a comprehensive overview of current gaps in inflammatory bowel diseases (IBDs) research and deliver actionable approaches to address them with a focus on how these gaps can lead to advancements in interception, remission, and restoration for these diseases. The document is the result of multidisciplinary input from scientists, clinicians, patients, and funders, and represents a valuable resource for patient-centric research prioritization. In particular, the precision medicine section is focused on the main research gaps in elucidating how to bring the best care to the individual patient in IBD. Research gaps were identified in biomarker discovery and validation for predicting disease progression and choosing the most appropriate treatment for each patient. Other gaps were identified in making the best use of existing patient biosamples and clinical data, developing new technologies to analyze large datasets, and overcoming regulatory and payer hurdles to enable clinical use of biomarkers. To address these gaps, the Workgroup suggests focusing on thoroughly validating existing candidate biomarkers, using best-in-class data generation and analysis tools, and establishing cross-disciplinary teams to tackle regulatory hurdles as early as possible. Altogether, the precision medicine group recognizes the importance of bringing basic scientific biomarker discovery and translating it into the clinic to help improve the lives of IBD patients.

Peripheral and intestinal T lymphocyte subsets in dogs with chronic inflammatory enteropathy

BACKGROUND

Dysregulated T lymphocyte response is thought to play a key role in chronic intestinal inflammation (CIE).

OBJECTIVES

To evaluate the presence of changes in peripheral and intestinal T lymphocyte subsets and to describe potential immune and inflammatory biomarkers in dogs with CIE.

ANIMALS

Sixteen healthy dogs and 26 dogs were diagnosed with CIE.

METHODS

Prospective case-control study evaluating peripheral and intestinal T lymphocytes using flow cytometry and inflammatory markers obtained from complete blood cell counts.

RESULTS

Dogs with CIE had higher peripheral activated T helper (Th) lymphocytes (87/μL [18-273] CIE, 44/μL [16-162] healthy control (HC, P = .013) and regulatory T cells (Treg; 108/μL [2-257] CIE, 34/μL [1-114] HC, P = .004). In the intestinal epithelium, CIE dogs presented lower percentages of Th (4.55% [1.75-18.67] CIE, 8.77% [3.79-25.03] HC, P = .002), activated Th cells (0.16% [0.02-0.83] CIE, 0.33% [0.05-0.57] HC, P = .03) and CD4/CD8 ratio (0.08 [0.02-0.39] CIE, 0.21 [0.07-0.85] HC, P = .003). Conversely, higher percentage of activated T cytotoxic cells (20.24% [3.12-77.12] CIE, 12.32% [1.21-39.22] HC, P = .04) and interferon-gamma (IFN-γ) producing T lymphocytes (7.36% [0.63-55.83] CIE, 1.44% [0.00-10.56] HC, P = .01) within the epithelium was observed. In the lamina propria the percentage of Treg lymphocytes was higher (6.02% [1.00-21.48] CIE, 3.52% [0.18-10.52] HC, P = .02).

CONCLUSIONS AND CLINICAL IMPORTANCE

Systemic and intestinal immune alterations occur in dogs with CIE suggesting that blood IFN-γ producing T lymphocytes and the systemic immune-inflamation index (SII) could potentially serve as biomarkers for the disease.

Differential Immune Infiltration Profiles in Colitis-Associated Colorectal Cancer versus Sporadic Colorectal Cancer

BACKGROUND

Chronic inflammation is a significant factor in colorectal cancer (CRC) development, especially in colitis-associated CRC (CAC). T-cell exhaustion is known to influence inflammatory bowel disease (IBD) progression and antitumor immunity in IBD patients. This study aimed to identify unique immune infiltration characteristics in CAC patients.

METHODS

We studied 20 CAC and 20 sporadic CRC (sCRC) patients, who were matched by tumor stage, grade, and location. Immunohistochemical staining targeted various T-cell markers (CD3, CD4, CD8, and FOXP3), T-cell exhaustion markers (TOX and TIGIT), a B-cell marker (CD20), and a neutrophil marker (CD66b) in tumor and tumor-free mucosa from both groups. The quantification of the tumor immune stroma algorithm assessed immune-infiltrating cells.

RESULTS

CAC patients had significantly lower TOX+ cell infiltration than sCRC in tumors (p = 0.02) and paracancerous tissues (p < 0.01). Right-sided CAC showed increased infiltration of TOX+ cells (p = 0.01), FOXP3+ regulatory T-cells (p < 0.01), and CD20+ B-cells (p < 0.01) compared to left-sided CAC. In sCRC, higher tumor stages (III and IV) had significantly lower TIGIT+ infiltrate than stages I and II. In CAC, high CD3+ (p < 0.01) and CD20+ (p < 0.01) infiltrates correlated with improved overall survival. In sCRC, better survival was associated with decreased TIGIT+ cells (p < 0.038) and reduced CD8+ infiltrates (p = 0.02).

CONCLUSION

In CAC, high CD3+ and CD20+ infiltrates relate to improved survival, while this association is absent in sCRC. The study revealed marked differences in TIGIT and TOX expression, emphasizing distinctions between CAC and sCRC. T-cell exhaustion appears to have a different role in CAC development.

Friend or Foe - Tc17 cell generation and current evidence for their importance in human disease

The term Tc17 cells refers to interleukin 17 (IL-17)-producing CD8+ T cells. While IL-17 is an important mediator of mucosal defense, it is also centrally involved in driving the inflammatory response in immune-mediated diseases, such as psoriasis, multiple sclerosis, and inflammatory bowel disease. In this review, we aim to gather the current knowledge on the phenotypic and transcriptional profile, the in vitro and in vivo generation of Tc17 cells, and the evidence pointing towards a relevant role of Tc17 cells in human diseases such as infectious diseases, cancer, and immune-mediated diseases.

Inflammation, Autoinflammation and Autoimmunity in Inflammatory Bowel Diseases

In this review, the role of innate and adaptive immunity in the pathogenesis of inflammatory bowel diseases (IBD) is reported. In IBD, an altered innate immunity is often found, with increased Th17 and decreased Treg cells infiltrating the intestinal mucosa. An associated increase in inflammatory cytokines, such as IL-1 and TNF-α, and a decrease in anti-inflammatory cytokines, such as IL-10, concur in favoring the persistent inflammation of the gut mucosa. Autoinflammation is highlighted with insights in the role of inflammasomes, which activation by exogenous or endogenous triggers might be favored by mutations of NOD and NLRP proteins. Autoimmunity mechanisms also take place in IBD pathogenesis and in this context of a persistent immune stimulation by bacterial antigens and antigens derived from intestinal cells degradation, the adaptive immune response takes place and results in antibodies and autoantibodies production, a frequent finding in these diseases. Inflammation, autoinflammation and autoimmunity concur in altering the mucus layer and enhancing intestinal permeability, which sustains the vicious cycle of further mucosal inflammation.

The Promise of Single-Cell RNA Sequencing to Redefine the Understanding of Crohn's Disease Fibrosis Mechanisms

Crohn's disease (CD) is a chronic inflammatory bowel disease with a high prevalence throughout the world. The development of Crohn's-related fibrosis, which leads to strictures in the gastrointestinal tract, presents a particular challenge and is associated with significant morbidity. There are currently no specific anti-fibrotic therapies available, and so treatment is aimed at managing the stricturing complications of fibrosis once it is established. This often requires invasive and repeated endoscopic or surgical intervention. The advent of single-cell sequencing has led to significant advances in our understanding of CD at a cellular level, and this has presented opportunities to develop new therapeutic agents with the aim of preventing or reversing fibrosis. In this paper, we discuss the current understanding of CD fibrosis pathogenesis, summarise current management strategies, and present the promise of single-cell sequencing as a tool for the development of effective anti-fibrotic therapies.

Peripheral Multiple Cytokine Profiles Identified CD39 as a Novel Biomarker for Diagnosis and Reflecting Disease Severity in Allergic Rhinitis Patients

Background

Allergic rhinitis (AR) is a common clinical problem, and immune cells and cytokines were proven to be pivotal in its pathogenesis. Our aim is to measure the peripheral concentrations of multiple cytokines in AR patients and identify novel biomarkers for diagnosis and disease severity.

Methods

Peripheral blood samples were collected from 50 AR patients, including 25 mild AR (MAR) patients and 25 moderate-severe AR patients (MSAR), and 22 healthy controls (HCs), and multiple cytokine profiling was outlined by Luminex assay. Cytokine levels were compared among the three groups, and their correlations with disease severity were evaluated. The candidate cytokines were further verified by enzyme-linked immunosorbent assay (ELISA) in a validation cohort.

Results

Multiple cytokine profiling revealed that CD39 and interferon (IFN)-γ levels were reduced, and interleukin (IL)-13, IL-5, IL-33, and thymic stromal lymphopoietin (TSLP) levels were elevated in the AR group than the HC group (P < 0.05). Receiver operating characteristic (ROC) curves presented that serum CD39 and IL-33 exhibited strong diagnostic abilities, and serum CD39 and IL-10 presented capacities in distinguishing disease severity (AUC > 0.8, P < 0.05). Moreover, CD39 concentrations were decreased, and IL-10, IL-5, and TSLP concentrations were enhanced in the MSAR group more than in the MAR group. Correlation analysis results showed that serum CD39, IL-5, and TSLP levels were associated with total nasal symptom score (TNSS) and visual analogue score (VAS) (P < 0.05). Further data in the validation cohort suggested that serum CD39 levels were reduced, and IL-5 and TSLP levels were increased in AR patients, especially in MSAR patients (P < 0.05). ROC results revealed potential values of serum CD39 in diagnosis and disease severity evaluation in AR patients (P < 0.05).

Conclusion

This study highlighted that peripheral multiple cytokine profiles were significantly varied in AR patients and associated with disease severity. The results in discover-validation cohorts implied that serum CD39 might serve as a novel biomarker for diagnosing AR and reflecting its disease severity.

Landscapes and mechanisms of CD8+ T cell exhaustion in gastrointestinal cancer

CD8+ T cells, a cytotoxic T lymphocyte, are a key component of the tumor immune system, but they enter a hyporeactive T cell state in long-term chronic inflammation, and how to rescue this depleted state is a key direction of research. Current studies on CD8+ T cell exhaustion have found that the mechanisms responsible for their heterogeneity and differential kinetics may be closely related to transcription factors and epigenetic regulation, which may serve as biomarkers and potential immunotherapeutic targets to guide treatment. Although the importance of T cell exhaustion in tumor immunotherapy cannot be overstated, studies have pointed out that gastric cancer tissues have a better anti-tumor T cell composition compared to other cancer tissues, which may indicate that gastrointestinal cancers have more promising prospects for the development of precision-targeted immunotherapy. Therefore, the present study will focus on the mechanisms involved in the development of CD8+ T cell exhaustion, and then review the landscapes and mechanisms of T cell exhaustion in gastrointestinal cancer as well as clinical applications, which will provide a clear vision for the development of future immunotherapies.