Increased Interleukin-17F is Associated with Elevated Autoantibody Levels and More Clinically Relevant Than Interleukin-17A in Primary Sjögren's Syndrome

A GITRL-mTORC1-GM-CSF Positive Loop Promotes Pathogenic Th17 Response in Primary Sjögren Syndrome

OBJECTIVE

Glucocorticoid-induced tumor necrosis factor receptor superfamily-related protein (GITR), with its ligand (GITRL), plays an important role in CD4+ T cell-mediated autoimmunity. This study aimed to investigate the underlying mechanisms of GITRL in primary Sjögren syndrome (pSS).

METHODS

Patients with pSS and healthy controls were recruited. Serum GITRL and Th17-related cytokines were determined. RNA sequencing was performed to decipher key signal pathways. Nonobese diabetes (NOD) mice were adopted as experimental Sjögren models and recombinant adeno-associated virus (rAAV) transduction was conducted to verify the therapeutic potentials of targeting GITRL in vivo.

RESULTS

Serum GITRL was significantly higher in patients with pSS and showed a positive correlation with leukopenia, thrombocytopenia, autoantibodies, lung involvement, and disease activity. Serum GITRL was correlated with Th17-related cytokines. GITRL promoted the expansion of Th17 and Th17.1 cells. Expansion of granulocyte-macrophage colony-stimulating factor positive (GM-CSF+) CD4+ T cells induced by GITRL could be inhibited by blockade of GITRL. Moreover, GM-CSF could stimulate GITRL expression on monocytes. RNA sequencing revealed mammalian target of rapamycin complexes 1 (mTORC1) might be the key modulator. The increased phosphorylation of S6 and STAT3 and the expansion of Th17 and Th17.1 cells induced by GITRL were effectively inhibited by rapamycin, suggesting a GITRL-mTORC1-GM-CSF positive loop in pathogenic Th17 response in pSS. Administration of an rAAV vector expressing short hairpin RNA targeting GITRL alleviated disease progression in NOD mice.

CONCLUSION

Our results identified the pathogenic role of GITRL in exacerbating disease activity and promoting pathogenic Th17 response in pSS through a GITRL-mTORC1-GM-CSF loop. These findings suggest GITRL might be a promising therapeutic target in the treatment of pSS.

Primary biliary cholangitis has causal effects on systemic rheumatic diseases: a Mendelian randomization study

BACKGROUND

An association has been observed between primary biliary cholangitis (PBC) and systemic rheumatic diseases (SRDs) in observational studies, however the exact causal link remains unclear. We aimed to evaluate the causal effects of PBC on SRDs through Mendelian randomization (MR) analysis.

METHODS

The genome-wide association study (GWAS) summary data were obtained from MRC IEU OpenGWAS and FinnGen databases. Independent genetic variants for PBC were selected as instrumental variables. Inverse variance weighted was used as the main approach to evaluate the causal effects of PBC on Sjögren syndrome (SS), rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), systemic sclerosis (SSc), mixed connective tissue disease (MCTD) and polymyositis (PM). Horizontal pleiotropy and heterogeneity were measured by MR‒Egger intercept test and Cochran's Q value, respectively.

RESULTS

PBC had causal effects on SS (OR = 1.177, P = 8.02e-09), RA (OR = 1.071, P = 9.80e-04), SLE (OR = 1.447, P = 1.04e-09), SSc (OR = 1.399, P = 2.52e-04), MCTD (OR = 1.306, P = 4.92e-14), and PM (OR = 1.416, P = 1.16e-04). Based on the MR‒Egger intercept tests, horizontal pleiotropy was absent (all P values > 0.05). The robustness of our results was further enhanced by the leave-one-out method.

CONCLUSIONS

Our research has provided new insights into PBC and SRDs, indicating casual effects on various SRDs.

Advances in cellular and molecular pathways of salivary gland damage in Sjögren's syndrome

Sjögren's Syndrome (SS) is an autoimmune disorder characterized by dysfunction of exocrine glands. Primarily affected are the salivary glands, which exhibit the most frequent pathological changes. The pathogenesis involves susceptibility genes, non-genetic factors such as infections, immune cells-including T and B cells, macrophage, dendritic cells, and salivary gland epithelial cells. Inflammatory mediators such as autoantibodies, cytokines, and chemokines also play a critical role. Key signaling pathways activated include IFN, TLR, BAFF/BAFF-R, PI3K/Akt/mTOR, among others. Comprehensive understanding of these mechanisms is crucial for developing targeted therapeutic interventions. Thus, this study explores the cellular and molecular mechanisms underlying SS-related salivary gland damage, aiming to propose novel targeted therapeutic approaches.

Identification and verification of inflammatory biomarkers for primary Sjögren's syndrome

INTRODUCTION

Primary Sjögren's syndrome (pSS) is an autoimmune disease characterized by inflammatory infiltration, and dysfunction of the salivary and lacrimal glands. This research aimed to explore the disease pathogenesis and improve the diagnosis and treatment of pSS by mining inflammation-associated biomarkers.

METHODS

Five pSS-related datasets were retrieved from the Gene Expression Omnibus (GEO) database. Inflammation-associated biomarkers were determined by the least absolute shrinkage and selection operator (LASSO) and support vector machines recursive feature elimination (SVM-RFE). Single sample gene set enrichment analysis (ssGSEA) was implemented to profile the infiltration levels of immune cells. Real-time quantitative PCR (RT-qPCR) verified the expression of biomarkers in clinical samples.

RESULTS

Four genes (LY6E, EIF2AK2, IL15, and CXCL10) were screened as inflammation-associated biomarkers in pSS, the predictive performance of which were determined among three pSS-related datasets (AUC > 0.7). Functional enrichment results suggested that the biomarkers were involved in immune and inflammation-related pathways. Immune infiltration analysis revealed that biomarkers were notably connected with type 2 T helper cells, regulatory T cells which were significantly expressed between pSS and control. TESTOSTERONE and CYCLOSPORINE were predicted to take effect by targeting CXCL10 and IL15 in pSS, respectively.

CONCLUSION

Four inflammation-associated biomarkers (LY6E, EIF2AK2, IL15, and CXCL10) were explored, and the underlying regulatory mechanisms and targeted drugs associated with these biomarkers were preliminarily investigated according to a series of bioinformatics methods based on the online datasets of pSS, which provided a reference for understanding the pathogenesis of pSS. Key Points • Inflammation-associated biomarkers (LY6E, EIF2AK2, IL15, and CXCL10) were firstly identified in Sjögren's syndrome based on LASSO and SVM-RFE analyses. • CXCL10, EIF2AK2 and LY6E were prominently positively correlated with immature B cells, while IL15 were significantly negatively correlated with memory B cells in Sjögren's syndrome. • LY6E, EIF2AK2, IL15, and CXCL10 were significantly more highly expressed in clinical Sjögren's syndrome samples compared to healthy control samples, which was consistent with the analysis results of the GEO database. •LY6E, EIF2AK2, IL15, and CXCL10 might be used as the biomarkers for the treatment and diagnosis of Sjögren's syndrome.

IL-21, not IL-17A, exacerbates murine primary biliary cholangitis

Primary biliary cholangitis (PBC) is a chronic autoimmune liver disease caused by intrahepatic bile duct injuries, resulting in fibrosis, cirrhosis, and eventually liver failure. T helper (Th) 17 cells are proposed to involve in the pathogenesis of PBC. However, how and which Th17 cell-derived cytokines affect PBC remains unclear. In this study, we investigated the effects of Th17 effector cytokines, including interleukin (IL)-17A, IL-17F, and IL-21 in PBC using a xenobiotic-induced mouse model of autoimmune cholangitis (inducible chemical xenobiotic models of PBC) treated with cytokine-expressing adeno-associated virus. Our results showed that administration of IL-17A, the well-known main cytokine produced by Th17 cells, did not augment liver inflammation or fibrosis. In contrast, we noted IL-17A-treated mice had lower hepatic Th1 cell numbers and higher hepatic CD11b+Ly6G+ polymorphonuclear myeloid-derived suppressor cell numbers. IL-17F did not alter liver inflammation or fibrosis. However, the administration of IL-21 exacerbated liver inflammatory responses and portal cell infiltration. IL-21 markedly increased the numbers of activated CD8+ T cells and liver tissue-resident memory CD8+ T cells. Moreover, IL-21 aggravates liver fibrosis in mice with autoimmune cholangitis. These results emphasized that not IL-17A but IL-21 in Th17 cell-derived cytokines affected the pathogenesis of PBC. IL-21 enhanced liver inflammation and progression to fibrosis by enhancing the numbers and effector activities of CD8+ T cells. Delineation of the effects of different Th17 effector cytokines in PBC offers clues for developing new therapeutic approaches.

Association of Inflammatory Cytokine Levels with Extra Glandular Manifestations, Fatigue, and Disease Activity in Primary Sjögren's Syndrome in Saudi Patients: A Cross-Sectional Study

BACKGROUND

Primary Sjögren's syndrome (pSS) is an autoimmune disease that can cause fatigue and extraglandular manifestations (EGMs). pSS is associated with cytokine network dysregulation, which may be related to the immune-mediated destruction of exocrine glands.

OBJECTIVE

We determined cytokine levels and their relationship to EGMs, the European League Against Rheumatism (EULAR) Sjögren's syndrome disease activity index (ESSDAI), and fatigue in Saudi patients with pSS.

METHODS

This study was a cross-sectional, single-center study. We included forty-one patients and 71 controls. Serum samples were collected from random healthy people and pSS patients who were followed in the rheumatology and pulmonary clinics of King Saud University Medical City in Riyadh, Saudi Arabia. Levels of the frequently studied cytokines were measured using Luminex xMAP technology. Each ESSDAI score and EGM were recorded, and the Arabic version of the fatigue severity scale (FSS) was applied to assess fatigue. The main outcome measures were cytokine levels in pSS Saudi patients using/not using immune-suppressive medications (ISMs).

RESULTS

Thirty-six (87.8%) patients had one or more EGMs, and the mean ESSDAI score was 9.95 ± 7.73. There was a significant decrease in TNFα and IL-21 levels in the pSS group compared to those in the control group (p = 0.034 and p < 0.001, respectively), whereas IL-12 levels were significantly elevated in the pSS group (p = 0.002). Cytokine levels in patients who used ISMs were the same as those in patients who did not use medications. Decreased IL-1β (p = 0.014), IL-2 (p = 0.035), IL-6 (p = 0.014), and IL-35 (p = 0.010) levels were observed in patients who had EGMs. Patients who had low disease activity exhibited low IL-10 (p = 0.018) and high IFN-α (p = 0.049), IFN-β (p = 0.049), IL-1β (p = 0.006), and IL-35 (p = 0.032) levels compared to patients with high disease activity. A negative association between a positive fatigue score and IL-1β (p = 0.010), IL-2 (p = 0.037), IFN-α (p = 0.025), TNFα (p = 0.030), IL-17 (p = 0.029), IL-12 (p = 0.046), and IL-21 (p = 0.005) levels was found.

CONCLUSIONS

Cytokine profiles correlate with EGMs, ESSDAI, and fatigue. Patients with controlled disease activity have a normal cytokine profile that is similar to that of controls.

Diagnostic Evaluation Using Salivary Gland Ultrasonography in Primary Sjögren's Syndrome

The purpose of this study is to investigate the clinical manifestations in patients with early primary Sjögren's syndrome (pSS) based on the severity score found by salivary gland ultrasonography. Thirty-five newly diagnosed patients with early pSS were enrolled and divided into mild (score 0-1) and severe (score 2-3) groups according to the salivary gland ultrasonography grade (SGUS) scores at baseline. Clinical evaluation, ESSPRI and ESSDAI index values, sicca symptoms of the mouth, salivary capacity, and serum autoantibodies and cytokines were investigated. The mean age of pSS patients at diagnosis was 49.9 ± 11.9 years, and the mean duration of sicca symptoms was 0.58 years. ESSPRI (EULAR Sjögren's syndrome patient report index) and ESSDAI (EULAR Sjögren's syndrome disease index) scores were 15.97 and 4.77, respectively. Clinical manifestations, including the low production of saliva and autoantibody production, such as antinuclear antibodies, rheumatoid factor, and anti-SSA antibody, were found. A higher prevalence of rheumatoid factor (p = 0.0365) and antinuclear antibody (p = 0.0063) and a higher elevation of total IgG (p = 0.0365) were found in the severe group than in the mild group. In addition, the elevated titer of IL-25 was detected in the severe group than in the mild group. This observation indicated that salivary gland ultrasonography grade (SGUS) scans may help physicians diagnose pSS and the elevated titer of IL-25 in patients may be implicated in the pathogenesis of pSS.

MAIT cells and their implication in human oral diseases

OBJECTIVE

Mucosal-associated invariant T (MAIT) cells are unique innate-like T cells that are abundant in humans, accounting for 1-10% of circulating T cells and about 2% of total T cells in human oral cavity. MAIT cells can mount a strong immune response quickly without exogenous antigens and undergo a phenotypic transformation in the development of diseases. They produce cytokines involved in the Th1 and Th17 immune response and cytotoxic proteins, promote the dysfunction of autoreactive B cell and inhibit the function of NK cells. MAIT cells have been widely explored in autoimmune diseases, inflammatory diseases and tumors, and these mechanisms may also be involved in the pathogenesis of some oral diseases, while MAIT cells have not been systematically discussed in oral diseases.

METHODS

We searched PubMed/MEDLINE, EMBASE and Microsoft Bing databases to review and analyze relevant literatures on the impact of MAIT cells in the pathogenesis of human oral diseases.

CONCLUSION

Collected evidence elucidated the characteristics of MAIT cells and emphasized the potential roles of MAIT cells in oral lichen planus (OLP), chronic graft-versus-host disease (cGVHD), oral squamous cell carcinoma (OSCC), apical periodontitis (AP) and primary Sjogren's syndrome (pSS).

Low Dose Interleukin-2 Ameliorates Sjögren's Syndrome in a Murine Model

Sjögren's syndrome (SS) is a systemic autoimmune disease with no efficient treatment, and it is associated with dysregulated immune cells and impaired interleukin (IL)-2 signaling. IL-2 is critical for the development and maintenance of Treg cells. The use of low dose of IL-2 (LDIL-2) in the treatment of autoimmune diseases is promising, but the efficacy and mechanism in SS therapy are still to be confirmed. This study aims to investigate the therapeutic effect of LDIL-2 on SS in NOD (non-obese diabetic) mice. NOD mice (female, 8 weeks old) were randomly assigned into three groups (n = 8). Low dose of IL-2 (LDIL-2), high dose of IL-2 (HDIL-2), and isometric sterile water (control) were administered subcutaneously daily from week 8 to week 16. LDIL-2 administration significantly recovered the reduction in saliva flow and suppressed lymphocyte inflammation of the submandibular glands (SMGs) when compared with those treated with sterile water as controls (p < 0.05). SS related biomarkers including ANA, Anti-SSA/Ro, and Anti-SSB/La also declined (p < 0.05). In the low dose of IL-2 treated group, the proportion of CD4+CD25+Foxp3+Tregs in both spleen and cervical-lymph-node were higher than control mice (p < 0.05). Furthermore, CD4+Bcl-6+PD-1+CXCR5+Tfh cells, CD4+IFN-γ+Th1 cells, and CD4+IL-17A+Th17 cells were significantly reduced in LDIL-2 group (p < 0.05). Analysis of the SMGs biopsies showed significantly decreased inflammation scores after LDIL-2 administration and an increase of Tregs with immunohistochemical staining. Our findings provide in vivo evidence that LDIL-2 was an effective therapeutic intervention for SS observed in NOD mice and may restore immune balance through the promotion of Treg and suppression of germinal center (GC) B cells and effector T cells.

Roles of IL-25 in Type 2 Inflammation and Autoimmune Pathogenesis

Interleukin-17E (IL-25) is a member of the IL-17 cytokine family that includes IL-17A to IL-17F. IL-17 family cytokines play a key role in host defense responses and inflammatory diseases. Compared with other IL-17 cytokine family members, IL-25 has relatively low sequence similarity to IL-17A and exhibits a distinct function from other IL-17 cytokines. IL-25 binds to its receptor composed of IL-17 receptor A (IL-17RA) and IL-17 receptor B (IL-17RB) for signal transduction. IL-25 has been implicated as a type 2 cytokine and can induce the production of IL-4, IL-5 and IL-13, which in turn inhibits the differentiation of T helper (Th) 17. In addition to its anti-inflammatory properties, IL-25 also exhibits a pro-inflammatory effect in the pathogenesis of Th17-dominated diseases. Here, we review recent advances in the roles of IL-25 in the pathogenesis of inflammation and autoimmune diseases.

Role of the IL-23/IL-17 Pathway in Rheumatic Diseases: An Overview

Interleukin-23 (IL-23) is a pro-inflammatory cytokine composed of two subunits, IL-23A (p19) and IL-12/23B (p40), the latter shared with Interleukin-12 (IL-12). IL-23 is mainly produced by macrophages and dendritic cells, in response to exogenous or endogenous signals, and drives the differentiation and activation of T helper 17 (Th17) cells with subsequent production of IL-17A, IL-17F, IL-6, IL-22, and tumor necrosis factor α (TNF-α). Although IL-23 plays a pivotal role in the protective immune response to bacterial and fungal infections, its dysregulation has been shown to exacerbate chronic immune-mediated inflammation. Well-established experimental data support the concept that IL-23/IL-17 axis activation contributes to the development of several inflammatory diseases, such as PsA, Psoriasis, Psoriatic Arthritis; AS, Ankylosing Spondylitis; IBD, Inflammatory Bowel Disease; RA, Rheumatoid Arthritis; SS, Sjogren Syndrome; MS, Multiple Sclerosis. As a result, emerging clinical studies have focused on the blockade of this pathogenic axis as a promising therapeutic target in several autoimmune disorders; nevertheless, a greater understanding of its contribution still requires further investigation. This review aims to elucidate the most recent studies and literature data on the pathogenetic role of IL-23 and Th17 cells in inflammatory rheumatic diseases.

Cytokine profiles and clinical characteristics in primary Sjögren´s syndrome patient groups

BACKGROUND

Primary Sjögren's syndrome (pSS) is an autoimmune disease characterized by a lymphocytic infiltrate in salivary glands driving to epithelial damage. The pSS patients present heterogenic clinical and serological characteristics. This heterogenicity could be due to the cytokine microenvironment. Cytokine levels have been analyzed and reported individually, showing controversial results; for that reason, we considered essential to evaluate a cluster of cytokines and relate them with antibody levels and clinical characteristics to find pSS subgroups.

METHODS

Ninety-nine pSS patients, diagnosed by the 2016 ACR/EULAR classification criteria, and 76 control subjects (CS) were included. Cytokine quantification was performed by Multiplex assay. Principal component analysis (PCA) was realized, and the K-mean test was used to identify clusters/groups. Groups were analyzed by the Kruskal-Wallis test and the Bonferroni test.

RESULTS

Higher IFN-γ, IL-17F, IL-21, IL-23, IL-4, and IL-31 levels were observed in pSS patients in comparison with control subjects. PCA analysis showed three groups. The severe group was characterized by higher cytokine concentrations as well as an increase in clinical parameters such as antibody levels, damage index score, and others. The moderate group presented intermediate severity; meanwhile, the mild group presented the lowest severity.

CONCLUSION

Cluster analysis revealed three groups that were different in cytokine levels and clinical parameters in which the mild group was defined by lower severity, the moderate group with intermediate severity, and the severe group with higher severity. This analysis could help subclassify the primary Sjögren syndrome patients for a better understanding of the clinical phenotype that impacts the treatment approach.

Can cinnamon spice down autoimmune diseases?

Autoimmune diseases are one of the dreadful group of human diseases that have always been of keen interest to researchers. Due to complex and broad-spectrum nature, scientists are not yet able to pinpoint the pathogenesis of and delineate effective therapy against this group of diseases. However, it is becoming clear that a decrease in number and function of T regulatory cells (Treg), an increase in autoreactive Th1/Th17 cells and associated immunomodulation and inflammation participate in the pathogenesis of many autoimmune diseases. Cinnamon (Cinnamonum verum or Cinnamonum cassia) is a widely used natural spice and flavoring ingredient and its metabolite sodium benzoate (NaB) is a food-additive and FDA-approved drug against nonketotic hyperglycinemia (NKH) and urea cycle disorders (UCD). Recent studies indicate that cinnamon either in powder or extract form and NaB are capable of modulating different autoimmune pathways as well as protecting animals from different autoimmune disorders. Here, we have made an honest attempt to delineate such pieces of evidence with available anti-autoimmune mechanisms and analyze whether cinnamon supplements could be used to control the fury of autoimmune disorders.

T Cells Subsets in the Immunopathology and Treatment of Sjogren's Syndrome

Sjogren´s syndrome (SS) is an autoimmune disease whose pathogenesis is characterized by an exacerbated T cell infiltration in exocrine glands, markedly associated to the inflammatory and detrimental features as well as the disease progression. Several helper T cell subsets sequentially converge at different stages of the ailment, becoming involved in specific pathologic roles. Initially, their activated phenotype endows them with high migratory properties and increased pro-inflammatory cytokine secretion in target tissues. Later, the accumulation of immunomodulatory T cells-derived factors, such as IL-17, IFN-γ, or IL-21, preserve the inflammatory environment. These effects favor strong B cell activation, instigating an extrafollicular antibody response in ectopic lymphoid structures mediated by T follicular helper cells (Tfh) and leading to disease progression. Additionally, the memory effector phenotype of CD8+ T cells present in SS patients suggests that the presence of auto-antigen restricted CD8+ T cells might trigger time-dependent and specific immune responses. Regarding the protective roles of traditional regulatory T cells (Treg), uncertain evidence shows decrease or invariable numbers of circulating and infiltrating cells. Nevertheless, an emerging Treg subset named follicular regulatory T cells (Tfr) seems to play a critical protective role owing to their deficiency that enhances SS development. In this review, the authors summarize the current knowledge of T cells subsets contribution to the SS immunopathology, focusing on the cellular and biomolecular properties allowing them to infiltrate and to harm target tissues, and that simultaneously make them key therapeutic targets for SS treatment.

Cutaneous and Mucosal Manifestations of Sjögren's Syndrome

Sjögren's syndrome is currently considered an "autoimmune epithelitis," as exocrine glands, especially salivary and lacrimal, are progressively destructed by an immune-mediated process associated with specific serum autoantibodies and local lymphocyte infiltrate. Xerostomia remains a key complain in patients with Sjögren's syndrome but should be evaluated also for other causes such as xerogenic medications, followed by radiation and chemotherapy for head and neck cancers, hormone disorders, infections, or other connective tissue diseases. Further, xerophtalmia (also known as dry eye) frequently associated with keratoconjunctivitis sicca cumulatively affects approximately 10-30% of the general population with increasing incidence with age and is more frequently secondary to non-autoimmune diseases. On the other hand, numerous patients with Sjögren's syndrome manifest signs of systemic dryness involving the nose, the trachea, the vagina, and the skin, suggesting that other glands are also affected beyond the exocrine epithelia. Skin involvement in Sjögren's syndrome is relatively common, and various manifestations may be present, in particular xeroderma, eyelid dermatitis, annular erythema, and cutaneous vasculitis. Additional skin non-vasculitic manifestations include livedo reticularis which may occur in the absence of vasculitis, and localized nodular cutaneous amyloidosis possibly representing lymphoproliferative diseases related to Sjögren's syndrome. The treatment of skin and mucosal manifestations in Sjögren's syndrome is similar regardless of the cause, starting from patient education to avoid alcohol and tobacco smoking and to pursue dental hygiene. In conclusion, a strict collaboration between the dermatologist and the rheumatologist is essential in the adequate management of Sjögren's syndrome skin and mucosal manifestations.

Genetic polymorphisms of IL-17A rs2275913, rs3748067 and IL-17F rs763780 in gastric cancer risk: evidence from 8124 cases and 9873 controls

Interleukin-17 (IL-17) is a critical cytokine involved in inflammation-associated cancers. Single nucleotide polymorphisms (SNPs) might promote carcinogenesis. In this current meta-analysis, we investigated the association of IL-17A and IL-17F gene polymorphisms with gastric cancer (GC) risk. Eligible genetic association studies were retrieved from PubMed, Web of Science and Scopus database sources. Two reviewers independently assessed methodological quality and extracted data from eligible articles. Pooled odds ratios (ORs) and 95% confidence intervals (CIs) were calculated. Quantitative data synthesis was conducted using comprehensive meta-analysis v2. Subgroup analysis and heterogeneity analysis were performed. Begg's funnel plot and Egger's regression tests were used to judge publication bias. In silico data analysis was executed to analyze the functional and structural impact of the SNPs. A total of 21 case-control studies for rs2275913 c.-197G > A (7660 patients and 9409 controls), 9 studies for rs3748067 c.*1249C > T (3378 patients and 4120 controls), and 14 studies for rs763780 c.482A > G (4481 patients and 5354 controls) were included. The pooled estimate revealed an association between IL-17A rs2275913 polymorphism and the risk of GC under all genetic models (A vs. G, OR 1.187, 95% CI 1.086-1.297, P < 0.001; GA vs. GG, OR 1.108, 95% CI 1.008-1.218, P = 0.033; AA vs. GG, OR 1.484, 95% CI 1.236-1.781, P < 0.001), while no evidence of association was found with IL-17A rs3748067 or IL-17F rs763780 polymorphisms. Our results showed that IL-17A promoter rs2275913 variant might represent a potential risk factor for gastric cancer susceptibility.

TCRαβ+CD3+CD4-CD8- (double negative) T cells in autoimmunity

TCRαβ⁺CD3⁺CD4^-CD8^- "double negative" (DN) T cells comprise a small subset of mature peripheral T cells. The origin and function of DN T cells are somewhat unclear and discussed controversially. While DN T cells resemble a rare and heterogeneous T cell subpopulation in healthy individuals, numbers of TCRαβ⁺ DN T cells are expanded in several inflammatory conditions, where they also exhibit distinct effector phenotypes and infiltrate inflamed tissues. Thus, DN T cells may be involved in systemic inflammation and tissue damage in autoimmune/inflammatory conditions, including SLE, Sjögren's syndrome, and psoriasis. Here, the current understanding of the origin and phenotype of DN T cells, and their role in the instruction of immune responses, autoimmunity and inflammation will be discussed in health and disease.

Chronic Autoimmune Epithelitis in Sjögren's Syndrome and Primary Biliary Cholangitis: A Comprehensive Review

Within the spectrum of autoimmune diseases, Sjögren's syndrome and primary biliary cholangitis are exemplary and can be coined as chronic epithelitis based on their frequent coexistence in clinical practice and the highly specific immune-mediated injury of the small bile ducts and the exocrine glands. The pathogenic mechanisms underlying the diseases are similar, with apoptosis being the key element leading to organ-specific immune-mediated injury directed against the small bile ducts and salivary gland epithelia, respectively along with similar epidemiological features, such as female predominance and the age of onset in the fifth decade of life. Indeed, novel insights into the pathogenesis of the diseases have been obtained in recent years, including a better definition of the role of B and T cells, particularly Th17 cells, and the mechanisms of autoantibody-mediated tissue injury, with anti-mitochondrial antibodies and SS-A/SS-B being identified as specific for primary biliary cholangitis and Sjögren's syndrome, respectively. These findings have opened the possibility to new targeted therapies, but most clinical needs remain unmet, particularly from a therapeutic standpoint where options diverge, with bile acids being the predominant treatment strategy in primary biliary cholangitis and immunomodulators being used to treat Sjögren's syndrome. Here we provide a comprehensive review of the most recent findings on the pathogenesis, clinical manifestations and therapeutic options for Sjögren's syndrome and primary biliary cholangitis, respectively, while stressing the common traits between these conditions. Our cumulative hypothesis is that similarities outnumber differences and that this may prove advantageous towards a better management of patients.