Disturbance of cytokine networks in Sjögren's syndrome

Endogenous IL-22 contributes to the pathogenesis of salivary gland dysfunction in the non-obese diabetic model of Sjögren's syndrome

Sjӧgren's syndrome is a systemic autoimmune disease primarily targeting the salivary and lacrimal glands. Our previous investigations have shown that administration of interleukin-22 (IL-22), an IL-10 family cytokine known for its complex and context-dependent effects on tissues, either protective- or detrimental, to salivary glands leads to hypofunction and pathological changes of salivary glands in C57BL/6 mice and in non-obese diabetic (NOD) mice, the latter being a commonly used model of Sjӧgren's syndrome. This study aims to delineate the pathophysiological roles of endogenously produced IL-22 in the development of salivary gland pathologies and dysfunction associated with Sjӧgren's disease in the NOD mouse model. Our results reveal that neutralizing IL-22 offered a protective effect on salivary gland function without significantly affecting the immune cell infiltration of salivary glands or the autoantibody production. Blockade of IL-22 reduced the levels of phosphorylated STAT3 in salivary gland tissues of NOD mice, while its administration to salivary glands had the opposite effect. Correspondingly, the detrimental impact of exogenously applied IL-22 on salivary glands was almost completely abrogated by a specific STAT3 inhibitor. Moreover, IL-22 blockade led to a downregulation of protein amounts of Ten-Eleven-Translocation 2, a methylcytosine dioxygenase critical for mediating interferon-induced responses, in salivary gland epithelial cells. IL-22 neutralization also exerted a protective effect on the salivary gland epithelial cells that express high levels of surface EpCAM and bear the stem cell potential, and IL-22 treatment in vitro hampered the survival/expansion of these salivary gland stem cells, indicating a direct negative impact of IL-22 on these cells. In summary, this study has uncovered a critical pathogenic role of the endogenous IL-22 in the pathogenesis of Sjögren's disease-characteristic salivary gland dysfunction and provided initial evidence that this effect is dependent on STAT3 activation and potentially achieved through fostering Tet2-mediated interferon responses in salivary gland epithelial cells and negatively affecting the EpCAMhigh salivary gland stem cells.

Altered characteristics of regulatory T cells in target tissues of Sjögren's syndrome in murine models

Sjӧgren's syndrome (SS), also known as Sjögren's disease, is a chronic autoimmune condition predominantly affecting the salivary and lacrimal glands. The disease is driven by autoimmune responses involving the activation and actions of major innate- and adaptive immune cell subsets. However, the specific characteristics and roles of regulatory T cells (Tregs) in SS remain elusive. This study seeks to clarify the main phenotypic and functional attributes of Tregs in the salivary glands and their draining lymph nodes in murine models of SS. Our flow cytometric analysis revealed that Tregs in the salivary gland-draining lymph nodes of female non-obese diabetic (NOD) mice, a spontaneous model of SS, exhibited a greater proportion of activated Tregs and fewer resting Tregs compared to Balb/c mice. Furthermore, Tregs from the salivary gland-draining lymph nodes of female C57BL/6.NOD-Aec1Aec2 (B6.NOD-Aec) mice, a model for primary SS, demonstrated significantly lower IL-10 production but markedly higher IFNγ- and IL-17 production than their C57BL/6 counterparts. Additionally, treatment of C57BL/6 Tregs with IL-7, a cytokine critical for SS pathogenesis, resulted in diminished IL-10 production and enhanced IFNγ and IL-17 production in these cells. Notably, the alterations in B6.NOD-Aec Tregs also included an increased expression of the immune-inhibitory molecule CTLA-4 compared to the C57BL/6 Tregs. Intriguingly, in vitro co-cultures of Tregs with conventional CD4 T cells and other key immune populations from lymph nodes indicated that Tregs from salivary gland-draining lymph nodes of both B6.NOD-Aec and C57BL/6 strains exhibited comparable and limited immunosuppressive effects on the proliferation and function of conventional CD4 T cells. The ability of B6.NOD-Aec Tregs to directly inflict damages to salivary gland epithelial tissues and contribute to SS pathologies through IFNγ and IL-17 that they produce warrants further investigations. In addition, enhancing the relatively weak immunosuppressive capacities of these Tregs may also serve as a viable strategy to alleviate the SS phenotype in the mouse models and potentially in patients.

KLRB1 defines an activated phenotype of CD4+ T cells and shows significant upregulation in patients with primary Sjögren's syndrome

OBJECTIVE

This study aimed to investigate the role of KLRB1 (CD161) in human CD4+ T cells and elucidate its significance in primary Sjögren's syndrome (pSS).

METHODS

Peripheral blood samples from 37 healthy controls and 44 pSS patients were collected. The publicly available single-cell RNA-Seq data from pSS patient PBMCs were utilized to analyse KLRB1 expression in T cells. KLRB1-expressing T lymphocyte subset proportions in pSS patients and healthy controls were determined by flow cytometry. CD25, Ki-67, cytokine secretion, and chemokine receptor expression in CD4+ KLRB1+ T cells were detected and compared with those in CD4+ KLRB1- T cells. Correlation analysis was conducted between KLRB1-related T-cell subsets and clinical indicators. ROC curves were generated to explore the diagnostic potential of KLRB1 for pSS.

RESULTS

KLRB1 was significantly upregulated following T-cell activation, and Ki-67 and CD25 expression was significantly greater in CD4+ KLRB1+ T cells than in CD4+ KLRB1- T cells. KLRB1+ CD4+ T cells exhibited greater IL-17A, IL-21, IL-22, and IFN-γ secretion upon stimulation, and there were significantly greater proportions of CCR5+, CCR2+, CX3CR1+, CCR6+, and CXCR3+ cells among CD4+ KLRB1+ T cells than among CD4+ KLRB1- T cells. Compared with that in HCs, KLRB1 expression in CD4+ T cells was markedly elevated in pSS patients and significantly correlated with clinical disease indicators.

CONCLUSION

KLRB1 is a characteristic molecule of the CD4+ T-cell activation phenotype. The increased expression of KLRB1 in the CD4+ T cells of pSS patients suggests its potential involvement in the pathogenesis of pSS and its utility as an auxiliary diagnostic marker for pSS.

TLR7 activation of age-associated B cells mediates disease in a mouse model of primary Sjögren's disease

Primary Sjögren's disease (pSD) (also referred to as Sjögren's syndrome) is an autoimmune disease that primarily occurs in women. In addition to exocrine gland dysfunction, pSD patients exhibit B cell hyperactivity. B cell-intrinsic TLR7 activation is integral to the pathogenesis of systemic lupus erythematosus, a disease that shares similarities with pSD. The role of TLR7-mediated B cell activation in pSD, however, remains poorly understood. We hypothesized that age-associated B cells (ABCs) were expanded in pSD and that TLR7-stimulated ABCs exhibited pathogenic features characteristic of disease. Our data revealed that ABC expansion and TLR7 expression were enhanced in a pSD mouse model in a Myd88-dependent manner. Splenocytes from pSD mice showed enhanced sensitivity to TLR7 agonism as compared with those derived from control animals. Sort-purified marginal zone B cells and ABCs from pSD mice showed enhanced inflammatory cytokine secretion and were enriched for antinuclear autoantibodies following TLR7 agonism. Finally, IgG from pSD patient sera showed elevated antinuclear autoantibodies, many of which were secreted preferentially by TLR7-stimulated murine marginal zone B cells and ABCs. These data indicate that pSD B cells are hyperresponsive to TLR7 agonism and that TLR7-activated B cells contribute to pSD through cytokine and autoantibody production. Thus, therapeutics that target TLR7 signaling cascades in B cells may have utility in pSD patients.

Inflammatory cytokines and their potential role in Sjogren's syndrome risk: insights from a mendelian randomization study

AIM

This study aimed to investigate the causal impact of inflammatory cytokines on Sjogren's Syndrome (SS) and to identify potential biomarkers for SS clinical management using Mendelian Randomization (MR).

MATERIALS AND METHODS

Leveraging GWAS summary data of inflammatory cytokines and SS, we executed the first two-sample MR analysis. Genetic variants from prior GWASs associated with circulating inflammatory cytokines served as instrumental variables (IVs). Data regarding cytokines were analyzed using the Olink Target-96 Inflammation panel, synthesizing data from 14,824 participants. GWAS summary statistics for SS were procured from the UK Biobank, focusing on samples of European ancestry. To discern the causal relationship between inflammatory cytokines and SS, several MR methodologies, including inverse variance weighted (IVW) and MR-Egger regression, were applied.

RESULTS

After rigorous IV quality control, 91 cytokines were incorporated into the MR analysis. The IVW analysis identified 8 cytokines with a positive association to SS: Axin-1 (OR 2.56, 95% CI 1.07-6.10), T-cell surface glycoprotein CD5 (OR 1.81, 95% CI 1.08-3.02), CUDP1 (OR 1.61, 95% CI 1.00-2.58), CXCL10 (OR 1.92, 95% CI 1.25-2.95), IL-4 (OR 2.18, 95% CI 1.22-3.91), IL-7 (OR 2.35, 95% CI 1.27-4.33), MCP-2 (OR 1.27, 95% CI 1.05-1.54), and TNFRSF9 (OR 1.83, 95% CI 1.03-3.24), suggesting their potential in increasing SS risk.

CONCLUSION

Our study conducted through MR, identified various inflammatory cytokines associated with SS risk, validating some previous research results and offering some new potential biomarkers for SS. However, these findings necessitate further research for validation and exploration of their precise role in the onset and progression of SS.

B Cells Dynamic in Aging and the Implications of Nutritional Regulation

Aging negatively affects B cell production, resulting in a decrease in B-1 and B-2 cells and impaired antibody responses. Age-related B cell subsets contribute to inflammation. Investigating age-related alterations in the B-cell pool and developing targeted therapies are crucial for combating autoimmune diseases in the elderly. Additionally, optimal nutrition, including carbohydrates, amino acids, vitamins, and especially lipids, play a vital role in supporting immune function and mitigating the age-related decline in B cell activity. Research on the influence of lipids on B cells shows promise for improving autoimmune diseases. Understanding the aging B-cell pool and considering nutritional interventions can inform strategies for promoting healthy aging and reducing the age-related disease burden.

Exploring the relationship between oxidative stress status and inflammatory markers during primary Sjögren's syndrome: A new approach for patient monitoring

INTRODUCTION

Primary Sjögren's syndrome (pSS) is a chronic inflammatory disease primarily affects exocrine glands dysfunction. Oxidative stress (OS) is a phenomenon occurring as a result of an imbalance between the generation of free radicals and antioxidant defense system. Hence, we aimed to establish the status of OS and inflammatory response according to the pSS disease activity index. In this context, we investigated malondialdehyde (MDA), and antioxidant enzymes during pSS. The possible association between MDA and nitric oxide (NO) levels and between MDA and some pro-inflammatory cytokines (IL-1β, IL-6, TNF-α, and IL-33).

METHODS

The study has been conducted on 53 pSS patients. The antioxidant enzymes, represented by glutathione peroxidase (GSH-Px), catalase (CAT) and superoxide dismutase (SOD), were estimated by a colorimetric activity kit. Whereas, MDA value was assessed by measuring thiobarbituric acid reactive substances. Moreover, pro-inflammatory cytokines (IL-1β, IL-6, TNF-α, and IL-33) and NO were respectively quantified by enzyme-linked immunosorbent assays (ELISA) and the modified Griess.

RESULTS

Interestingly, we report a notable reduction in our pSS patients' antioxidant enzyme activity, while NO, MDA and proinflammatory cytokines values were significantly increased. pSS patients with higher disease activity had much stronger increases in NO and MDA levels. No significant difference was assessed in CRP level. Additionally, substantial significant correlations between plasmatic NO and MDA levels and between MDA, NO and IL-1β, IL-6, TNF-α cytokines were reported. However, no significant association was found between NO, MDA and IL-33 concentrations.

CONCLUSION

Collectively, our data showed altered oxidant-antioxidant balance in pSS patients. MDA, NO, IL-1β, IL-6, TNF-α seem to be good indicators in monitoring disease activity. Oxidative stress was closely related to inflammation in pSS. Exploiting this relationship might provide valuable indicators in the follow-up and prognosis of pSS with a potential therapeutic value.

Effect of acupuncture on regulating IL-17, TNF-ɑ and AQPs in Sjögren's syndrome

AIM

The aim of the study was to observe the effect of acupuncture on regulating interleukin (IL)-17, tumor necrosis factor (TNF)-ɑ, and aquaporins (AQPs) in Sjögren's syndrome (SS) on patients and on non-obese diabetic (NOD) models.

METHODS

Levels of anti-AQP 1, 5, 8, and 9 antibodies, IL-17, and TNF-ɑ in the serum of SS patients were compared prior and following 20 acupuncture treatment visits during 8 weeks. While in murine model, five groups were divided to receive interventions for 4 weeks, including control, model, acupuncture, isoflurane, and hydroxychloroquine. The submaxillofacial gland index, histology, immunohistochemistry of AQP1, 5, salivary flow, together with IL-17, and TNF-ɑ expression in peripheral blood were compared among the groups.

RESULTS

Acupuncture reduced IL-17, TNF-ɑ, and immunoglobin A levels, and numeric analog scale of dryness in 14 patients with SS (p < 0.05). The salivary flow was increased, and the water intake decreased in NOD mice receiving acupuncture treatments. IL-17 and TNF-ɑ levels in peripheral serum were down-regulated (p < 0.05) and AQP1, 5 expression in the submandibular glands up-regulated in mice.

CONCLUSION

The effect on relieving xerostomia with acupuncture may be achieved by up-regulating the expression of AQP1. AQP5, down-regulating levels of IL-17 and TNF-ɑ, and a decrease in inflammation of glands.

Evaluation of the Efficacy and Safety of Topical 0.05% Cyclosporine Eye Drops (II) in the Treatment of Dry Eye Associated with Primary Sjögren's Syndrome

PURPOSE

To evaluate the efficacy and safety of 0.05% cyclosporine eye drops (II) for the treatment of primary Sjögren's syndrome-associated dry eye (PSSDE).

METHODS

Sixty patients with PSSDE were randomly divided into three groups, received treatment with 0.05% cyclosporine (C group), artificial tears (S group) or their combination (CS group). The evaluation indicators were evaluated at baseline and at weeks 2, 4 and 12.

RESULTS

The symptoms of C and CS groups were reduced significantly. The signs [schirmer I test (F = 4.838, p = .011), ocular staining score (F = 7.961, p = .001) and tear break-up time (F = 9.283, p < .001)] were significantly different between S and C groups as well as S and CS groups. The tear meniscus height (F = 3.197, p = .048) was significantly different between S and CS groups. No serious adverse events occurred.

CONCLUSION

0.05% cyclosporine is an effective and safe treatment for patients with PSSDE.

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.

Endothelial Dysfunction in Primary Sjögren's Syndrome: Correlation with Serum Biomarkers of Disease Activity

To assess the relationship between endothelial dysfunction and serum cytokines, anti-SSA and anti-SSB antibodies, beta-2 microglobulin levels, focus score and EULAR Sjögren's Syndrome Disease Activity Index (ESSDAI) in primary Sjögren's syndrome (pSS) patients. The study included 90 patients with pSS and 45 healthy subjects, matched for age and gender, as controls. Serum beta-2 microglobulin, total cholesterol, HDL-cholesterol, triglycerides, TNF-α, and IL-6 were analyzed in both the groups. Patients with pSS were also tested for antinuclear antibodies, anti-SAA (anti-Sjögren's syndrome-related antigen A) antibodies, anti-SSB (anti-Sjögren syndrome related antigen B) antibodies, and focus score (the histopathologic one, based on minor salivary gland biopsy). Endothelial dysfunction was assessed by means of flow-mediated dilation (FMD) in the brachial artery. Data are presented as mean ± standard deviation. Statistical analysis was performed using the t-test and the Pearson's correlation. Differences were considered to be statistically significant if the value of p < 0.05. Endothelial dysfunction was identified in pSS patients (p < 0.00001). The serum levels of cytokines (TNF-α, respective IL-6) and beta-2 microglobulin were increased in pSS patients compared with controls (p < 0.00001). Endothelial dysfunction (expressed as FMD%) was correlated with focus score, ESSDAI, levels of anti-SSA and anti-SSB antibodies, beta-2 microglobulin, IL-6, and TNF-α, with statistical significance. Endothelial dysfunction is present in pSS patients and is associated with a high focus score and activity as well as increased concentrations of antibodies, pro-inflammatory cytokines, and beta 2-microglobulin.

Outline of Salivary Gland Pathogenesis of Sjögren's Syndrome and Current Therapeutic Approaches

Sjögren's syndrome (SS) is an autoimmune disease characterized by the involvement of exocrine glands such as the salivary and lacrimal glands. The minor salivary glands, from which tissue samples may be obtained, are important for the diagnosis, evaluation of therapeutic efficacy, and genetic analyses of SS. In the onset of SS, autoantigens derived from the salivary glands are recognized by antigen-presenting dendritic cells, leading to the activation of T and B cells, cytokine production, autoantibody production by plasma cells, the formation of ectopic germinal centers, and the destruction of salivary gland epithelial cells. A recent therapeutic approach with immune checkpoint inhibitors for malignant tumors enhances the anti-tumor activity of cytotoxic effector T cells, but also induces SS-like autoimmune disease as an adverse event. In the treatment of xerostomia, muscarinic agonists and salivary gland duct cleansing procedure, as well as sialendoscopy, are expected to ameliorate symptoms. Clinical trials on biological therapy to attenuate the hyperresponsiveness of B cells in SS patients with systemic organ involvement have progressed. The efficacy of treatment with mesenchymal stem cells and chimeric antigen receptor T cells for SS has also been investigated. In this review, we will provide an overview of the pathogenesis of salivary gland lesions and recent trends in therapeutic approaches for SS.

The Spectrum of Extraglandular Manifestations in Primary Sjögren's Syndrome

Extraglandular manifestations (EGMs) in primary Sjogren's syndrome (pSS) represent the clinical expression of the systemic involvement in this disease. EGMs are characterized by a wide heterogeneity; virtually any organ or system can be affected, with various degrees of dysfunction. The existing gaps of knowledge in this complex domain of extraglandular extension in pSS need to be overcome in order to increase the diagnostic accuracy of EGMs in pSS. The timely identification of EGMs, as early as from subclinical stages, can be facilitated using highly specific biomarkers, thus preventing decompensated disease and severe complications. To date, there is no general consensus on the diagnostic criteria for the wide range of extraglandular involvement in pSS, which associates important underdiagnosing of EGMs, subsequent undertreatment and progression to severe organ dysfunction in these patients. This review article presents the most recent basic and clinical science research conducted to investigate pathogenic mechanisms leading to EGMs in pSS patients. In addition, it presents the current diagnostic and treatment recommendations and the trends for future therapeutic strategies based on personalized treatment, as well as the latest research in the field of diagnostic and prognostic biomarkers for extraglandular involvement in pSS.

The Role of Regulatory T Cells in the Onset and Progression of Primary Sjögren's Syndrome

Regulatory T cells (Tregs) play a key role in maintaining immune balance and regulating the loss of self-tolerance mechanisms in various autoimmune diseases, including primary Sjögren's syndrome (pSS). With the development of pSS primarily in the exocrine glands, lymphocytic infiltration occurs in the early stages, mainly due to activated CD4⁺ T cells. Subsequently, in the absence of rational therapy, patients develop ectopic lymphoid structures and lymphomas. While the suppression of autoactivated CD4⁺ T cells is involved in the pathological process, the main role belongs to Tregs, making them a target for research and possible regenerative therapy. However, the available information about their role in the onset and progression of this disease seems unsystematized and, in certain aspects, controversial. In our review, we aimed to organize the data on the role of Tregs in the pathogenesis of pSS, as well as to discuss possible strategies of cell therapy for this disease. This review provides information on the differentiation, activation, and suppressive functions of Tregs and the role of the FoxP3 protein in these processes. It also highlights data on various subpopulations of Tregs in pSS, their proportion in the peripheral blood and minor salivary glands of patients as well as their role in the development of ectopic lymphoid structures. Our data emphasize the need for further research on Tregs and highlight their potential use as a cell-based therapy.

Th17 cells in primary Sjögren’s syndrome negatively correlate with increased Roseburia and Coprococcus

Background

Dysbiosis of the gut microbiota is closely related to chronic systemic inflammation and autoimmunity, playing an essential role in the pathogenesis of primary Sjögren’s syndrome (pSS). Abnormalities in the proportions of blood T lymphocyte subtype, that is Th17/Treg, were detected in pSS patients. We aimed to determine the associations between gut microbiota and Th17/Treg in pSS.

Method

98 pSS patients and 105 healthy controls (NC) were enrolled between Dec 1, 2018, and Aug 31, 2019. The baseline information and clinical parameters on pSS patients and healthy controls were collected. 16S rRNA sequencing was performed to characterize the gut microbiome and identify gut microbes that are differentially abundant between patients and healthy controls. Lastly, associations between relative abundances of specific bacterial taxa in the gut and clinical outcome parameters were evaluated.

Results

Patients with pSS show decreased gut microbial diversity and richness, decreased abundance of butyrate producing bacteria, such as Roseburia and Coprococcus, and increased abundance of other taxa, such as Eubacterium rectale and Roseburia inulinivorans. These bacteria are enriched with functions related to glycolytic and lipogenic, energy, substance, galactose, pentose metabolism pathways and glucuronate interconversions, decreased with functions related to peptidoglycan biosynthesis, pyrimidine metabolism pathways. An integrative analysis identified pSS-related specific bacterial taxa in the gut, for which the abundance of Eubacterium rectale is negatively correlated with Th17/Treg. Furthermore, the pathways of biosynthesis of secondary metabolites, biosynthesis of amino acids, peptidoglycan biosynthesis and pyrimidine, galactose, pentose, microbial metabolism in diverse environments, glyoxylate and dicarboxylate metabolism are associated with Treg or Th17/Treg.

Conclusions

Primary Sjögren’s syndrome could lead to decreased gut microbial diversity and richness of intestinal flora in patients. The proportions of Th17 and Treg cells induced by microbiota were predictive pSS manifestations and accounted for the pSS severity.

Identification of Two Genetic Loci Associated with Leukopenia after Chemotherapy in Patients with Breast Cancer

PURPOSE

To identify molecular predictors of grade 3/4 neutropenic or leukopenic events (NLE) after chemotherapy using a genome-wide association study (GWAS).

EXPERIMENTAL DESIGN

A GWAS was performed on patients in the phase III chemotherapy study SUCCESS-A (n = 3,322). Genotyping was done using the Illumina HumanOmniExpress-12v1 array. Findings were functionally validated with cell culture models and the genotypes and gene expression of possible causative genes were correlated with clinical treatment response and prognostic outcomes.

RESULTS

One locus on chromosome 16 (rs4784750; NLRC5; P = 1.56E-8) and another locus on chromosome 13 (rs16972207; TNFSF13B; P = 3.42E-8) were identified at a genome-wide significance level. Functional validation revealed that expression of these two genes is altered by genotype-dependent and chemotherapy-dependent activity of two transcription factors. Genotypes also showed an association with disease-free survival in patients with an NLE.

CONCLUSIONS

Two loci in NLRC5 and TNFSF13B are associated with NLEs. The involvement of the MHC I regulator NLRC5 implies the possible involvement of immuno-oncological pathways.

Abnormal Epigenetic Regulations in the Immunocytes of Sjögren's Syndrome Patients and Therapeutic Potentials

Sjögren's syndrome (SjS), characterized by keratoconjunctivitis sicca and dry mouth, is a common autoimmune disease, especially in middle-aged women. The immunopathogenesis of SjS is caused by the sequential infiltration of T and B cells into exocrine glands, including salivary and lacrimal glands. Effector cytokines produced by these immunocytes, such as interferons (IFNs), IL-17, IL-22, IL-21, IL-4, TNF-α, BAFF and APRIL, play critical roles in promoting autoimmune responses and inducing tissue damages. Epigenetic regulations, including DNA methylation, histone modification and non-coding RNAs, have recently been comprehensively studied during the activation of various immunocytes. The deficiency of key epigenetic enzymes usually leads to aberrant immune activation. Epigenetic modifications in T and B cells are usually found to be altered during the immunopathogenesis of SjS, and they are closely correlated with autoimmune responses. In particular, the important role of methylation in activating IFN pathways during SjS progression has been revealed. Thus, according to the involvement of epigenetic regulations in SjS, target therapies to reverse the altered epigenetic modifications in auto-responsive T and B cells are worthy of being considered as a potential therapeutic strategy for SjS.

Effects of proinflammatory cytokines on lacrimal gland myoepithelial cells contraction

In the lacrimal gland, myoepithelial cells (MEC) express muscle contractile proteins such as alpha smooth muscle actin (SMA) and calponin and therefore can contract to help expel lacrimal fluid. In a previous study, we demonstrated that lacrimal gland MEC express the oxytocin receptor (OXTR) and they contract under oxytocin (OXT) stimulation. Using NOD and MRL/lpr mice (animal models of Sjogren's syndrome), we reported a decrease in SMA and calponin protein levels plus a decline in acini contraction after stimulation with OXT. It is known that proinflammatory cytokines, such as interleukin-1β (IL-1β), tumor necrosis factor alpha (TNF-α) or interferon gamma (IFN-γ), can affect OXTR expression and signaling capacity and inhibit MEC contraction. The aim of the current study was to investigate if proinflammatory cytokines are implicated in the loss of MEC contractile ability. Thus, lacrimal gland MEC from a SMA-GFP transgenic mouse were treated with IL-1β (10 ng/ml) for a total of 7 days. At days 0, 2, 4 and 7, GFP intensity, cell size/area, contractile proteins amounts and MEC contraction were assessed. At day 0, control and treated cells showed no differences in GFP intensity and cell size. GFP intensity started to decrease in treated MEC at day 2 (20%; p=0.02), continuing after day 4 (25%; p=0.007) and 7 (30%; p=0.0001). Mean cell area was also reduced at day 2 (34%; p=0.0005), and after 4 (51%; p&lt;0.0001) and 7 days (30%; p=0.0015). The contraction assay at day 2 showed a 70% decrease of contraction in treated MEC (p&lt;0.0001), 73% (p&lt;0.0001) at day 4 and 82% (p=0.0015) at day 7 when compared to control. Levels of contractile proteins were measured on day 7 showing a decrease in SMA and calponin amount in treated MEC compared with the control group (around 30%; p=0.0016 and p=0.0206; respectively). Similar results were observed when TNF-α and IFN-γ were added along with IL-1β. Taken together the present data and those from our previous studies with Sjogren's syndrome mouse models, they strongly suggest that proinflammatory cytokines affect lacrimal gland MEC contractile ability that may account for the reduced tear secretion associated with Sjogren's syndrome dry eye disease.

Supra-lacrimal protein-based carriers for cyclosporine A reduce Th17-mediated autoimmunity in murine model of Sjögren's syndrome

Sjögren's syndrome (SS) is a multifactorial autoimmune disease with principal symptoms including inflammation and loss of function of lacrimal glands (LG) and salivary glands. While glandular infiltrates includes both B- and T-cells, CD4+ T cells are strongly implicated. Utilizing the male non-obese diabetic (NOD) mouse model of SS, this work: 1) identifies clinically-relevant elevations in cytokines (IL-17A, IL-2) in LG-derived CD4+ T cells; and 2) explores tissue-specific immunosuppression of SS using a novel protein-based drug carrier to concentrate cyclosporine A (CsA) directly in the LG. As a potent immunosuppressant, topical ophthalmic CsA is approved for dry eye disorders; however, it cannot effectively resolve inflammation due to limited accumulation in the LG. Systemic CsA has dose-limiting side effects that also limit its ability to block LG inflammation. Using elastin-like polypeptides (ELPs) fused genetically to cyclophilin, the intracellular cognate receptor of CsA, this manuscript reports a sustained-release formulation of CsA that maintains therapeutic drug concentrations in the LG and extends intervals between doses. This formulation blocked both in vitro Th17 cell differentiation and IL-17A secretion. In vivo treatment significantly decreased the abundance of Th17.1 cells, a helper cell population sharing phenotypes of both Th17 and Th1, in the LG of diseased NOD mice. Treatment with even a single dose of the sustained-release formulation was effective enough to improve basal levels of tear production. Thus, this sustained-release formulation suppressed local LG inflammation driven through IL-17 dependent pathways, while improving ocular surface function.

The Clinical and Immunological Activity Depending on the Presence of Interferon γ in Primary Sjögren’s Syndrome—A Pilot Study

The upregulation of IFN pathways and their stimulated genes is associated with primary Sjögren’s syndrome (pSS). The recent studies also indicate the involvement of interferon γ (IFNγ) in the pathogenesis of pSS. The study aimed to assess the clinical and immunological activity depending on the concentration of IFNγ in the peripheral blood in pSS patients. Methods: The study group consisted of patients over 18 years of age with a confirmed diagnosis of pSS. Based on the collected data, disease activity was assessed using the EULAR Sjögren’s syndrome disease activity index (ESSDAI) and the EULAR Sjögren’s syndrome patient reported index (ESSPRI). Results: Among 40 pSS patients, 33 (82%) showed increased levels of IFNγ. The group with positive IFNγ was younger (43 years) than the group with negative IFNγ (57 years) (p < 0.05). In the positive IFNγ group, the time to diagnosis was shorter (p < 0.05). There was a difference in ESSDAI among patients with and without IFNγ (p < 0.05). There were no differences between the groups in ESSPRI and the presence of cryoglobulins, specific anti-SSA, and anti-SSB antibodies and in C3 and C4 hypocomplementemia. RF occurred in both groups with a similar frequency (p = 0.6), but in patients with IFNγ presence, significantly higher RF titers were observed (34.9 vs. 10.5; p < 0.05). Conclusion: In the group of patients with positive IFNγ, the mean value of RF and ESSDAI was higher. This group was also younger than patients with pSS without IFNγ.

Uncovering potential single nucleotide polymorphisms, copy number variations and related signaling pathways in primary Sjogren's syndrome

Primary Sjogren’s syndrome (pSS) is a complex systemic autoimmune disease, which is difficult to accurately diagnose due to symptom diversity in patients, especially at earlier stages. We tried to find potential single nucleotide polymorphisms (SNPs), copy number variations (CNVs) and related signaling pathways. Genomic DNA was extracted from peripheral blood of 12 individuals (7 individuals from 3 pSS pedigrees and 5 sporadic cases) for whole-exome sequencing (WES) analysis. SNPs and CNVs were identified, followed by functional annotation of genes with SNPs and CNVs. Gene expression profile (involving 64 normal controls and 166 cases) was downloaded from the Gene Expression Omnibus database (GEO) dataset for differentially expression analysis. Sanger sequencing and in vitro validation was used to validate the identified SNPs and differentially expressed genes, respectively. A total of 5 SNPs were identified in both pedigrees and sporadic cases, such as FES, PPM1J, and TRAPPC9. A total of 3402 and 19 CNVs were identified in pedigrees and sporadic cases, respectively. Fifty-one differentially expressed genes were associated with immunity, such as BATF3, LAP3, BATF2, PARP9, and IL15RA. AMPK signaling pathway and cell adhesion molecules (CAMs) were the most significantly enriched signaling pathways of identified SNPs. Identified CNVs were associated with systemic lupus erythematosus, mineral absorption, and HTLV-I infection. IL2-STAT5 signaling, interferon-gamma response, and interferon-alpha response were significantly enriched immune related signaling pathways of identified differentially expressed genes. In conclusion, our study found some potential SNPs, CNVs, and related signaling pathways, which could be useful in understanding the pathological mechanism of pSS.

Autoimmune Epithelitis and Chronic Inflammation in Sjögren's Syndrome-Related Dry Eye Disease

Autoimmune epithelitis and chronic inflammation are one of the characteristic features of the immune pathogenesis of Sjögren’s syndrome (SS)-related dry eye disease. Autoimmune epithelitis can cause the dysfunction of the excretion of tear fluid and mucin from the lacrimal glands and conjunctival epithelia and meibum from the meibomian glands. The lacrimal gland and conjunctival epithelia express major histocompatibility complex class II or human leukocyte antigen-DR and costimulatory molecules, acting as nonprofessional antigen-presenting cells for T cell and B cell activation in SS. Ocular surface epithelium dysfunction can lead to dry eye disease in SS. Considering the mechanisms underlying SS-related dry eye disease, this review highlights autoimmune epithelitis of the ocular surface, chronic inflammation, and several other molecules in the tear film, cornea, conjunctiva, lacrimal glands, and meibomian glands that represent potential targets in the treatment of SS-related dry eye disease.

Herbal Formula SS-1 Increases Tear Secretion for Sjögren's Syndrome

Background: Sjögren’s syndrome (SS) is an autoimmune inflammatory disease that primarily affects the exocrine glands, leading to glandular dysfunction. The hallmark symptoms of SS are dry eyes and mouth, compromising the quality of life of patients and decreasing their capacity to perform their daily activities.

Objective: This study aims to evaluate the efficacy of the herbal formula SS-1 for its potential therapeutic benefits for patients with Sjögren’s syndrome.

Materials and Methods: The bioactivity profile of SS-1 was determined using four different SS-1 concentrations across 12 human primary cell systems of the BioMAP profile. After that, a randomized, double-blind, crossover, placebo-controlled trial was performed including 57 patients treated with SS-1 for 28 weeks.

Results: Biologically multiplexed activity profiling in cell-based models indicated that SS-1 exerted anti-proliferative activity in B cells and promoted anti-inflammatory and immunomodulatory activity. In the clinical trial, Schirmer’s test results revealed significant improvements in both eyes, with increases of 3.42 mm (95% CI, 2.44–4.41 mm) and 3.45 mm (95% CI, 2.32–4.59 mm), respectively, and a significant reduction in artificial tear use, which was −1.38 times/day, 95% CI, −1.95 to −0.81 times/day. Moreover, the increases in B-cell activating factor (BAFF) and B-cell maturation antigen (BCMA) levels were dampened by 53.20% (295.29 versus 555.02 pg/ml) and 58.33% (99.16 versus 169.99 pg/ml), respectively.

Conclusion: SS-1 treatment significantly inhibited B-cell maturation antigen. No serious drug-related adverse effects were observed. Oral SS-1 administration may be a complementary treatment for Sjögren’s syndrome.

Treatment of Sjögren's Syndrome with Mesenchymal Stem Cells: A Systematic Review

Mesenchymal stem cells (MSCs) are ubiquitous in the human body. Mesenchymal stem cells were initially isolated from bone marrow and later from other organs such as fatty tissues, umbilical cords, and gingiva. Their secretory capacities give them interesting immunomodulatory properties in cell therapy. Some studies have explored the use of MSCs to treat Sjögren's syndrome (SS), a chronic inflammatory autoimmune disease that mainly affects exocrine glands, including salivary and lacrimal glands, although current treatments are only palliative. This systematic review summarizes the current data about the application of MSCs in SS. Reports show improvements in salivary secretions and a decrease in lymphocytic infiltration in salivary glands in patients and mice with SS after intravenous or infra-peritoneal injections of MSCs. MSC injections led to a decrease in inflammatory cytokines and an increase in anti-inflammatory cytokines. However, the intrinsic mechanism of action of these MSCs currently remains unknown.

Immunobiology of T Cells in Sjögren's Syndrome

Sjögren's syndrome (SjS) is a systemic autoimmune disease marked by xerostomia (dry mouth), keratoconjunctivitis sicca (eye dryness), and other systematic disorders. Its pathogenesis involves an inflammatory process that is characterized by lymphocytic infiltration into exocrine glands and other tissues. Although the development of ectopic lymphoid tissue and overproduction of autoantibodies by hyperactive B cells suggest that they may promote SjS development, treatment directed towards them fails to induce significant laboratory or clinical improvement. T cells are overwhelming infiltrators in most phases of the disease, and the involvement of multiple T cell subsets of suggests the extraordinary complexity of SjS pathogenesis. The factors, including various cellular subtypes and molecules, regulate the activation and suppression of T cells. T cell activation induces inflammatory cell infiltration, B cell activation, tissue damage, and metabolic changes in SjS. Knowledge of the pathways that link these T cell subtypes and regulation of their activities are not completely understood. This review comprehensively summarizes the research progress and our understanding of T cells in SjS, including CD4⁺ T cells, CD8⁺ T_RM cells, and innate T cells, to provide insights into for clinical treatment.

The Multiple Roles of B Cells in the Pathogenesis of Sjögren's Syndrome

Primary Sjögren’s syndrome (pSS) is a chronic autoimmune disease characterized by lymphocytic infiltration and tissue destruction of exocrine glands such as salivary glands. Although the formation of ectopic lymphoid tissue in exocrine glands and overproduction of autoantibodies by autoreactive B cells highlight the critical involvement of B cells in disease development, the precise roles of various B cell subsets in pSS pathogenesis remain partially understood. Current studies have identified several novel B cell subsets with multiple functions in pSS, among which autoreactive age-associated B cells, and plasma cells with augmented autoantibody production contribute to the disease progression. In addition, tissue-resident Fc Receptor-Like 4 (FcRL4)⁺ B cell subset with enhanced pro-inflammatory cytokine production serves as a key driver in pSS patients with mucosa-associated lymphoid tissue (MALT)-lymphomas. Recently, regulatory B (Breg) cells with impaired immunosuppressive functions are found negatively correlated with T follicular helper (Tfh) cells in pSS patients. Further studies have revealed a pivotal role of Breg cells in constraining Tfh response in autoimmune pathogenesis. This review provides an overview of recent advances in the identification of pathogenic B cell subsets and Breg cells, as well as new development of B-cell targeted therapies in pSS patients.

Effect of the Chinese Herbal Medicine SS-1 on a Sjögren's Syndrome-Like Disease in Mice

Sjögren’s syndrome (SS) is an inflammatory autoimmune disease primarily affecting the exocrine glands; it has a major impact on patients’ lives. The Chinese herbal formula SS-1 is composed of Gan Lu Yin, Sang Ju Yin, and Xuefu Zhuyu decoction, which exerts anti-inflammatory, immunomodulatory, and antifibrotic effects. Our previous study demonstrated that SS-1 alleviates clinical SS. This study aimed to evaluate the efficacy and mechanism of the Chinese herbal formula SS-1 for salivary gland protein-induced experimental Sjögren’s syndrome (ESS). These results showed that ESS treatment with the Chinese herbal formula SS-1 (1500 mg/kg) significantly alleviated the severity of ESS. We found that SS-1 substantially improved saliva flow rates in SS mice and ameliorated lymphocytic infiltrations in submandibular glands. In addition, salivary gland protein-induced SS in mice treated with SS-1 significantly lowered proinflammatory cytokines (including IFN-γ, IL-6, and IL-17A) in mouse salivary glands and decreased serum anti-M3R autoantibody levels. In addition, we found that CD4+ T cells isolated from SS-1-treated SS mice significantly reduced the percentages of IFN-γ-producing CD4+ T cells (Th1) and IL-17A-producing CD4+ T cells (Th17). Our data show that SS-1 alleviates ESS through anti-inflammatory and immunomodulatory effects, which provides new insight into the clinical treatment of SS.

IL-14α as a Putative Biomarker for Stratification of Dry Eye in Primary Sjögren's Syndrome

Background

Dry eye is often the first presenting manifestation of primary Sjögren’s syndrome (pSS). Because of the high prevalence of dry eye disease in normal population, ophthalmologists urgently need a non-invasive and reliable screening test to diagnose dry eye associated SS patients, other than ocular symptoms and signs. Currently, there is no single test available. The correlation of serum IL-14α with pSS has been found in pSS mouse model.

Purpose

To evaluate whether IL-14α can serve as a biomarker to stratify dry eye in primary Sjögren’s syndrome and its correlation to BAFF in a cohort of patients with non-SS dry eye (NSDE), pSS with dry eye disease, rheumatoid arthritis (RA), and healthy controls (HC).

Methods

Retrospective study based on serum levels of IL-14α (defined by Western Blot) and BAFF (measured by ELISA) were evaluated among pSS with dry eye disease, NSDE, RA, and HC groups. Serum levels of SS related autoantibodies (Ro, La, SP1, PSP, and CA6) were also measured by ELISA.

Results

One hundred and eighty patients were included for the current study, patients were separated into four groups as defined by pSS (n=65), NSDE (n=20), RA (n=50) and HC (n=45). The level of serum IL-14α in pSS was significantly higher compared to NSDE, RA, and HC (p=0.0011, p=0.0052 and p<0.0001, respectively). The levels of serum BAFF in pSS was significantly higher than in NSDE and HC (p=0.0148 and p<0.0001, respectively, whereas the levels of serum BAFF in RA was only significantly higher than in HC (p=0.001), but the level of BAFF was no significant difference between pSS and RA. In pSS, there was a decrease in the serum levels of IL-14α associated with a longer duration of the disease. Also, there was a correlation between the serum levels of IL-14α and SS related autoantibodies such as anti-SSA/Ro and anti-SSB/La in pSS patients.

Conclusions

This is the first paper to report both IL-14α and BAFF could serve as a critical cytokine biomarker for the stratification of dry eye in primary Sjögren’s syndrome. This may help ophthalmologists to develop non-invasive metrics for the diagnosis of dry eye associated pSS.

The Involvement of Innate and Adaptive Immunity in the Initiation and Perpetuation of Sjögren's Syndrome

Sjogren’s syndrome (SS) is a chronic autoimmune disease characterized by the infiltration of exocrine glands including salivary and lachrymal glands responsible for the classical dry eyes and mouth symptoms (sicca syndrome). The spectrum of disease manifestations stretches beyond the classical sicca syndrome with systemic manifestations including arthritis, interstitial lung involvement, and neurological involvement. The pathophysiology underlying SS is not well deciphered, but several converging lines of evidence have supported the conjuncture of different factors interplaying together to foster the initiation and perpetuation of the disease. The innate and adaptive immune system play a cardinal role in this process. In this review, we discuss the inherent parts played by both the innate and adaptive immune system in the pathogenesis of SS.

Current State of Knowledge on Primary Sjögren's Syndrome, an Autoimmune Exocrinopathy

Primary Sjögren's syndrome (pSS) is a chronic systemic autoimmune rheumatic disease characterized by lymphoplasmacytic infiltration of the salivary and lacrimal glands, whereby sicca syndrome and/or systemic manifestations are the clinical hallmarks, associated with a particular autoantibody profile. pSS is the most frequent connective tissue disease after rheumatoid arthritis, affecting 0.3-3% of the population. Women are more prone to develop pSS than men, with a sex ratio of 9:1. Considered in the past as innocent collateral passive victims of autoimmunity, the epithelial cells of the salivary glands are now known to play an active role in the pathogenesis of the disease. The aetiology of the "autoimmune epithelitis" still remains unknown, but certainly involves genetic, environmental and hormonal factors. Later during the disease evolution, the subsequent chronic activation of B cells can lead to the development of systemic manifestations or non-Hodgkin's lymphoma. The aim of the present comprehensive review is to provide the current state of knowledge on pSS. The review addresses the clinical manifestations and complications of the disease, the diagnostic workup, the pathogenic mechanisms and the therapeutic approaches.

miR-744-5p contributes to ocular inflammation in patients with primary Sjogrens Syndrome

In primary Sjögren’s syndrome (pSS) the exocrine glands become infiltrated with lymphocytes instigating severe damage to the salivary and lacrimal glands causing dry eyes and dry mouth. Previous investigations have suggested that dysregulated localized and systemic inflammation contributes to the development and pathogenesis of pSS. A miR microarray performed in primary human conjunctival epithelial cells (PECs) demonstrated significant differences in miR expression at the ocular surface between pSS patients and healthy controls. MicroRNA-744-5p (miR-744-5p) was identified as being of particular interest, as its top predicted target is Pellino3 (PELI3), a known negative regulator of inflammation. Validation studies confirmed that miR-744-5p expression is significantly increased in PECs from pSS patients, whilst PELI3 was significantly reduced. We validated the miR-744 binding site in the 3’ untranslated region (UTR) of PELI3 and demonstrated that increasing PELI3 levels with a miR-744-5p antagomir in an inflammatory environment resulted in reduced levels of IFN dependent chemokines Rantes (CCL5) and CXCL10. These results reveal a novel role for miR-744-5p in mediating ocular inflammation via Pellino3 expression in pSS patients and suggest that miR-744-5p may be a potential therapeutic target for the management of severe dry eye disease and ocular inflammation in pSS patients.

Agonist-induced 4-1BB activation prevents the development of Sjӧgren's syndrome-like sialadenitis in non-obese diabetic mice

Activation of costimulatory receptor 4-1BB enhances T helper 1 (Th1) and CD8 T cell responses in protective immunity, and prevents or attenuates several autoimmune diseases by increasing Treg numbers and suppressing Th17 or Th2 effector response. We undertook this study to elucidate the impact of enforced 4-1BB activation on the development of Sjögren's syndrome (SS)-like sialadenitis in non-obese diabetic (NOD) model of this disease. An anti-4-1BB agnostic antibody was intraperitoneally injected to female NOD mice aged 7 weeks, prior to the disease onset that occurs around 10-11 weeks of age, 3 times weekly for 2 weeks, and the mice were analyzed for SS pathologies at age 11 weeks. The salivary flow rate was markedly higher in the anti-4-1BB-treated NOD mice compared to the IgG-treated controls. Anti-4-1BB treatment significantly reduced the leukocyte infiltration of the submandibular glands (SMGs) and the levels of serum antinuclear antibodies. Flow cytometric analysis showed that the percentages of CD4 T cells, Th17 cells and plasmacytoid dendritic cells among SMG leukocytes were markedly reduced by anti-4-1BB treatment, in conjunction with a reduction in SMG IL-23p19 mRNA levels and serum IL-17 concentrations. Although the proportion of Tregs and IL-10 mRNA levels in SMGs were not altered by 4-1BB activation, IL-10 mRNA levels in salivary gland-draining lymph nodes and serum IL-10 concentrations were both markedly increased. While anti-4-1BB treatment did not affect the amount of Th1 cells and IFNγ mRNA in the SMGs, it increased these measurables in salivary gland-draining lymph nodes. Hence, agonistic activation of 4-1BB impedes the development of SS-like sialadenitis and hyposalivation.

Autoantibody-Mediated Dysfunction of Salivary Glands Leads to Xerostomia in SKG Mice

Sjögren's syndrome (SS) is a chronic heterogeneous disease that mainly affects exocrine glands, leading to sicca syndromes such as xerostomia. Despite the second highest prevalence rate among systemic autoimmune diseases, its pathophysiology remains largely unknown. Here we report that SKG mice, a cardinal model of Th17 cell-mediated arthritis, also develop a secondary form of SS-like disorder upon systemic exposure to purified curdlan, a type of β-glucan. The reduced production of saliva was not caused by focal immune cell infiltrates but was associated with IgG deposits in salivary glands. Sera from curdlan-injected SKG mice contained elevated titers of IgG (predominantly IgG₁), autoantibody to the muscarinic type 3 receptor (M3R) and inhibited carbachol-induced Ca²⁺ signaling in salivary acinar cells. These results suggest that the Th17 cells that are elicited in SKG mice promote the production of salivary gland-specific autoantibodies including anti-M3R IgG; the antibodies are then deposited on acinar cells and inhibit M3R-mediated signaling required for salivation, finally leading to hypofunction of the salivary glands. This type II hypersensitivity reaction may explain the origin of secondary SS occurring without focal leukocyte infiltrates.

The role of Epstein-Barr virus infection in primary Sjögren's syndrome

PURPOSE OF REVIEW

The purpose of this article is to draw attention to the role of Epstein-Barr virus (EBV) virus in the pathogenesis of the primary Sjögren's syndrome. The article introduces the problem of consequences of EBV acute infection, and its reactivation, in association with the immune response modulation by the virus and with an increased risk of developing systemic autoimmune diseases and EBV-associated cancers.

RECENT FINDINGS

The knowledge about the mechanisms by which the virus may stay for years in a latent phase, unrecognized by the host response immune cells is constantly expanding. There are several mechanisms and theories about EBV influence on the autoimmune process in Sjogren's syndrome (pSS), including the similarity (molecular mimicry) between viral EBNA-2 protein and Ro-60 antigen or EBER-1 and EBER-2 viral proteins and La antigen.

SUMMARY

The influence of EBV infection on the development and course of pSS has been proven. It has also been established that both EBV and pSS result in the increased risk of tumor (especially lymphoma) development. In the light of these findings, new ways to manage EBV infections are being sought. Optimal methods for assessing EBV infection status are being devised. Research also aims at finding therapies, which target EBV through the inhibition of the autoimmune process and of viral activity. The present article is an attempt to discuss the most important phenomena and elements linking EBV infection to the primary Sjögren's syndrome.

MicroRNA-130a Contributes to Type-2 Classical DC-activation in Sjögren's Syndrome by Targeting Mitogen- and Stress-Activated Protein Kinase-1

Objectives: Considering the critical role of microRNAs (miRNAs) in regulation of cell activation, we investigated their role in circulating type-2 conventional dendritic cells (cDC2s) of patients with primary Sjögren's syndrome (pSS) compared to healthy controls (HC). Methods: CD1c-expressing cDC2s were isolated from peripheral blood. A discovery cohort (15 pSS, 6 HC) was used to screen the expression of 758 miRNAs and a replication cohort (15 pSS, 11 HC) was used to confirm differential expression of 18 identified targets. Novel targets for two replicated miRNAs were identified by SILAC in HEK-293T cells and validated in primary cDC2s. Differences in cytokine production between pSS and HC cDC2s were evaluated by intracellular flow-cytometry. cDC2s were cultured in the presence of MSK1-inhibitors to investigate their effect on cytokine production. Results: Expression of miR-130a and miR-708 was significantly decreased in cDC2s from pSS patients compared to HC in both cohorts, and both miRNAs were downregulated upon stimulation via endosomal TLRs. Upstream mediator of cytokine production MSK1 was identified as a novel target of miR-130a and overexpression of miR-130a reduced MSK1 expression in cDC2s. pSS cDC2s showed higher MSK1 expression and an increased fraction of IL-12 and TNF-α-producing cells. MSK1-inhibition reduced cDC2 activation and production of IL-12, TNF-α, and IL-6. Conclusions: The decreased expression of miR-130a and miR-708 in pSS cDC2s seems to reflect cell activation. miR-130a targets MSK1, which regulates pro-inflammatory cytokine production, and we provide proof-of-concept for MSK1-inhibition as a therapeutic avenue to impede cDC2 activity in pSS.

Usefulness of rheumatoid factor as an immunological and prognostic marker in PSS patients

INTRODUCTION

The rheumatoid factor (RF) is present in numerous autoimmune disorders, although its role in many of them remains a subject of research. The study assesses the role of RF as an immunological and prognostic factor in the primary Sjögren's syndrome (pSS).

METHODS

Seventy-five pSS patients (mean age 50.03 ± 15.1), 65 (87%) females, and 10 (13%) males. WBC, CRP, RF, ESR, gammaglobulins, C4, C3 component of complement, cryoglobulins, ANA, anti-SS-A, and anti-SS-B antibodies were determined. The disease activity assessed with ESSDAI. Minor salivary gland biopsy (focus score and immunochemistry) was conducted. Results were analyzed with U Mann-Whitney (continuous variables) tests, correlations between quantitative variables assessed with the Spearman correlation coefficient with statistical significance set at p < 0.05. The approval of the Bioethics Committee was obtained.

RESULTS

Two subgroups I-RF(+) (61%) and II-RF(-) (39%) were established, with lower WBC (p = 0.012) and higher ESR (p = 0.016), gammaglobulin concentration (p = 0.007) in group I. Conjunctivitis sicca was more severe in group I. There was positive correlation between RF and lnANA (rho = 0.496), anti-SS-A, anti-SS-B antibodies (rho = 0.448; rho = 0.397 respectively). There was higher disease activity ESSDAI in group I than in group II (Me, 3.0 vs 2.0; p < 0.003). RF correlated negatively with WBC (rho = - 0.374). RF did not correlate with serum concentrations of BAFF, APRIL, CRP, and C3, C4 and with CD19+, CD3+, CD4+, CD 21+, and CD35+.

CONCLUSIONS

RF should be considered as a prognostic, but not diagnostic, factor in patients with pSS, as it is associated with more severe disease course (sicca eye symptoms, ESSDAI) and parameters (production of gammaglobulins, ANA, anti SS-A, anti-SS-B autoantibodies) indicating increased B cell activity.

Subgroups of Sjögren's syndrome patients categorised by serological profiles: clinical and immunological characteristics

Objectives

Sjögren's syndrome (SS) is an autoimmune disease characterised by heterogeneous clinical presentation and presence of various autoantibodies - anti-SSA/Ro of diagnostic value, less specific anti-SSB/La and others. We searched for biomarker(s) and potential therapeutic target(s) of SS subsets that vary in their autoantibody profile.

Material and methods

Eighty-one patients with SS (70 female and 11 male) and 38 healthy volunteers (28 female and 10 male) were included in the study. Patients were categorised according to absence (group 1) or presence of anti-SSA/Ro antibody which occurred either alone (group 2) or together with anti-SSB/La (group 3). Clinical evaluation was performed, and presence of autoantibodies and concentrations of cytokines relevant to SS pathogenesis, i.e. a proliferation inducing ligand (APRIL), B-lymphocyte activating factor (BAFF), interleukin (IL) 4, IL-10, interferon α (IFN-α) and thymic stromal lymphopoietin (TSLP), in sera were determined.

Results

Frequency of autoantibodies other than anti-SSA/Ro and anti-SSB/La, the number of autoantibody specificities and anti-nuclear antibody titres were higher in group 2 and/or 3 than in group 1 of SS patients. Moreover, SS patients of groups 2 and 3 developed disease symptoms at younger age, and more often had positive Schirmer's test and skin lesions. In addition, serum concentrations of APRIL, but not other tested cytokines, were significantly higher in the patients of both groups 2 and 3 than those of group 1 and healthy volunteers.

Conclusions

Sjögren's syndrome patients with signs of B-cell epitope spreading are characterised by early disease onset, more frequent xerophthalmia and skin involvement, and up-regulated serum APRIL level. We suggest that therapeutic neutralisation of APRIL may be beneficial for these patients.

Current and Emerging Evidence for Toll-Like Receptor Activation in Sjögren's Syndrome

While the importance of Toll-like receptor (TLR) signaling is well established in many autoimmune diseases, the role of TLR activation in Sjögren's syndrome (SS) is poorly understood. Studies in mice and humans reveal that TLRs are potent mediators of inflammation in SS. TLRs are expressed and functional in salivary tissue, and TLRs in peripheral blood cells of SS patients are also upregulated and hyperresponsive to ligation. In this review, we will detail observations in mouse models regarding the importance of TLR activation in both local and systemic disease. We will then discuss studies in SS patients that provide evidence of the importance of TLR-mediated signaling in disease. While the ligands that activate TLRs in the context of SS are unknown, emerging data suggest that damage-associated molecular patterns (DAMPs) may be significant drivers of the chronic and unremitting inflammation that is characteristic of SS. We will discuss putative DAMPs that may be of clinical significance in disease. Therapies that target TLR signaling cascades will likely reduce both exocrine-specific and systemic manifestations of SS.

Deciphering Molecular and Phenotypic Changes Associated with Early Autoimmune Disease in the Aire-Deficient Mouse Model of Sjögren's Syndrome

Sjögren's syndrome (SS) is characterized by extensive lymphocytic infiltration of the salivary and lacrimal gland (LG), resulting in acinar cell destruction and organ dysfunction. The underlying pathogenesis of SS remains largely unknown, and studies historically focus on defining late-stage disease. Here, we identify tissue programs associated with disease onset using transcriptomic and immunohistological analysis of LGs from 5- and 7-week-old mice deficient in autoimmune response element (Aire). At 5 weeks of age (wk), Aire-/- mice show minimal tissue dysfunction and destruction compared to 7 wk Aire-/-, which exhibit severe dry eye, poor tear secretion, extensive lymphocytic infiltration, reduced functional innervation, and increased vascularization. Despite this mild phenotype, 5 wk Aire-/- LGs were highly enriched for signaling pathways previously associated with SS, including interferon gamma (IFNγ), interleukin 1 beta (IL1β), nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), toll-like receptor (TLR) signaling, and interleukin-6/signal transducer and activator of transcription 3 (IL6/STAT3) signaling. Novel signaling pathways such as the semaphorin⁻plexin pathway were also noted. Intriguingly, we found an expansion of the ductal network with increasing disease. Activated STAT3, a blocker of apoptosis, was restricted to the ductal system and also increased with damage, highlighting its potential as a promoter of ductal cell survival. These data demonstrate the early activation of signaling pathways regulating inflammation, innervation, and cell survival before the onset of clinical disease indicators, suggesting their potential value as diagnostic biomarkers.

Interferons and Dry Eye in Sjögren's Syndrome

Various cytokines, including interferon (IFN)-γ and IL-17, are augmented, and autoreactive T cells and B cells are activated in the immune pathogenesis of Sjögren's syndrome (SS). In particular, IFNs are involved in both the early stages of innate immunity by high level of type I IFN in glandular tissue and sera and the later stages of disease progression by type I and type II IFN producing T cells and B cells through B cell activating factor in SS. Genetically modified mouse models for some of these molecules have been reported and will be discussed in this review. New findings from human SS and animal models of SS have elucidated some of the mechanisms underlying SS-related dry eye. We will discuss IFN-γ and several other molecules that represent candidate targets for treating inflammation in SS-related dry eye.

Sjögren-Like Lacrimal Keratoconjunctivitis in Germ-Free Mice

Commensal bacteria play an important role in the formation of the immune system but their role in the maintenance of immune homeostasis at the ocular surface and lacrimal gland remains poorly understood. This study investigated the eye and lacrimal gland phenotype in germ-free and conventional C57BL/6J mice. Our results showed that germ-free mice had significantly greater corneal barrier disruption, greater goblet cell loss, and greater total inflammatory cell and CD4⁺ T cell infiltration within the lacrimal gland compared to the conventionally housed group. A greater frequency of CD4⁺IFN-γ⁺ cells was observed in germ-free lacrimal glands. Females exhibited a more severe phenotype compared to males. Adoptive transfer of CD4⁺ T cells isolated from female germ-free mice into RAG1KO mice transferred Sjögren-like lacrimal keratoconjunctivitis. Fecal microbiota transplant from conventional mice reverted dry eye phenotype in germ-free mice and decreased CD4⁺IFN-γ⁺ cells to levels similar to conventional C57BL/6J mice. These findings indicate that germ-free mice have a spontaneous lacrimal keratoconjunctivitis similar to that observed in Sjögren syndrome patients and demonstrate that commensal bacteria function in maintaining immune homeostasis on the ocular surface. Thus, manipulation of intestinal commensal bacteria has the potential to become a novel therapeutic approach to treat Sjögren Syndrome.

Smad4 in T cells plays a protective role in the development of autoimmune Sjögren's syndrome in the nonobese diabetic mouse

We investigated the role of Smad4, a signaling molecule of the TGF-beta pathway, in T cells on the pathology of Sjögren's syndrome (SS) in nonobese diabetic (NOD) mice, an animal model of SS. T cell-specific Smad4-deleted (Smad4^{fl/fl,CD4-Cre}; Smad4 tKO) NOD mice had accelerated development of SS compared with wild-type (Smad4^+/+,CD4-Cre; WT) NOD mice, including increased lymphocyte infiltration into exocrine glands, decreased tear and saliva production, and increased levels of autoantibodies at 12 weeks of age. Activated/memory T cells and cytokine (IFN-γ, IL-17)-producing T cells were increased in Smad4 tKO NOD mice, however the proportion and function of regulatory T (Treg) cells were not different between Smad4 tKO and WT NOD mice. Effector T (Teff) cells from Smad4 tKO NOD mice were less sensitive than WT Teff cells to suppression by Treg cells. Th17 differentiation capability of Teff cells was similar between Smad4 tKO and WT NOD mice, but IL-17 expression was increased under inducible Treg skewing conditions in T cells from Smad4 tKO NOD mice. Our results demonstrate that disruption of the Smad4 pathway in T cells of NOD mice increases Teff cell activation resulting in upregulation of Th17 cells, indicating that Smad4 in T cells has a protective role in the development of SS in NOD mice.

Cardamonin inhibits pro-inflammatory cytokine production and suppresses NO pathway in PBMCs from patients with primary Sjögren's syndrome

Primary Sjögren's syndrome (pSS) is a systemic autoimmune disorder with a complex pathophysiology primarily affecting exocrine glands, leading to compromised secretory function. Recent studies imply that many inflammatory mediators, such as pro-inflammatory cytokines and nitric oxide, are critical in the development and perpetuation of pSS systemic manifestations. In the current study, we aimed to investigate the ex vivo immunomodulatory effect of cardamonin (C₁₆H₁₄O₄), on pro-inflammatory cytokines, TNF-α, IL-6 and inducible nitric oxide synthase (iNOS) expression during pSS. For this purpose, peripheral blood mononuclear cells isolated from pSS patients and healthy controls were cultured with different concentrations of cardamonin. Cytokine levels were measured by ELISA and NO production was assessed using the Griess method. Inducible nitric oxide synthase expression and NF-κB activity were analyzed by immunofluorescence staining. Our results suggest that cardamonin inhibits TNF-α, IL-6 and NO production and downregulates iNOS expression and NF-κB activation. Collectively, our results highlight the ex vivo immunomodulatory effects of cardamonin on pro-inflammatory cytokine production and NO pathway in pSS patients. Therefore, cardamonin is a potential candidate for controlling inflammation during pSS.

Management of primary Sjögren's syndrome: recent developments and new classification criteria

For many years primary Sjögren's syndrome (pSS) has been considered an orphan disease, since no specific therapies were recognized as being capable of contrasting the development and progression of this disorder. The treatment of oral and ocular features, as well as of the systemic organ involvement, has been entrusted to the joint management of different subspecialty physicians, like ophthalmologists, otolaryngologists, dentists and rheumatologists. These latter subspecialty doctors are usually more involved in the treatment of systemic extraglandular involvement and, to do it, they have long been using the conventional therapies borrowed by the treatment schedules adopted in other systemic autoimmune diseases. The increasing knowledge of the biological pathways that are operative in patients with pSS, and the parallel development of molecular biology technology, have allowed the production and availability of a number of biological agents able to positively act on different disease mechanisms, and thus are candidates for testing in therapeutic trials. Meanwhile, the scientific community has made a great effort to develop new accurate and validated classification criteria and outcome measures to be applied in the selection of patients to be included and monitored in therapeutic studies. Some of the new-generation biotechnological agents have been tested in a number of open-label and randomized controlled trials that have produced in many cases inconclusive or contradictory results. Behind the differences in trial protocols, adopted outcome measures and predefined endpoints, reasons for such unsatisfactory results can be found in the large heterogeneity of clinical subtypes in the examined cohorts. The future challenge for a substantial advancement in the therapeutic approach to pSS could be to identify the pathologic mechanisms, outcome tools and biomarkers that characterize the different subsets of the disease in order to test carefully selected target therapies with the highest probability of success in each different clinical phenotype.

Cytokines as therapeutic targets in primary Sjögren syndrome

Primary Sjögren syndrome (SjS) is a systemic autoimmune disease that may affect 1 in 1000 people (overwhelmingly women) and that can be a serious disease with excess mortality due to severe organ-specific involvements and the development of B cell lymphoma; systemic involvement clearly marks the disease prognosis, and strongly suggests the need for closer follow-up and more robust therapeutic management. Therapy is established according to the organ involved and severity. As a rule, the management of systemic SjS should be organ-specific, with glucocorticoids and immunosuppressive agents limited to potentially-severe involvements; unfortunately, the limited evidence available for these drugs, together with the potential development of serious adverse events, makes solid therapeutic recommendations difficult. The emergence of biological therapies has increased the therapeutic armamentarium available to treat primary SjS. Biologics currently used in SjS patients are used off-label and are overwhelmingly agents targeting B cells, but the most recent studies are moving on into the evaluation of targeting specific cytokines involved in the SjS pathogenesis. The most recent etiopathogenic advances in SjS are shedding some light in the search for new highly-selective biological therapies without the adverse effects of the standard drugs currently used (corticosteroids and immunosuppressant drugs). This review summarizes the potential pharmacotherapeutic options targeting the main cytokine families involved in the etiopathogenesis of primary SjS and analyzes potential insights for developing new therapies.

Interferon-γ treatment in vitro elicits some of the changes in cathepsin S and antigen presentation characteristic of lacrimal glands and corneas from the NOD mouse model of Sjögren's Syndrome

Inflammation and impaired secretion by lacrimal and salivary glands are hallmarks of the autoimmune disease, Sjögren’s Syndrome. These changes in the lacrimal gland promote dryness and inflammation of the ocular surface, causing pain, irritation and corneal damage. The changes that initiate and sustain autoimmune inflammation in the lacrimal gland are not well-established. Here we demonstrate that interferon-γ (IFN-γ) is significantly elevated in lacrimal gland and tears of the male NOD mouse, a model of autoimmune dacryoadenitis which exhibits many ocular characteristics of Sjögren’s Syndrome, by 12 weeks of age early in lacrimal gland inflammation. Working either with primary cultured lacrimal gland acinar cells from BALB/c mice and/or rabbits, in vitro IFN-γ treatment for 48 hr decreased expression of Rab3D concurrent with increased expression of cathepsin S. Although total cellular cathepsin S activity was not commensurately increased, IFN-γ treated lacrimal gland acinar cells showed a significant increase in carbachol-stimulated secretion of cathepsin S similar to the lacrimal gland in disease. In vitro IFN-γ treatment did not increase the expression of most components of major histocompatibility complex (MHC) class II-mediated antigen presentation although antigen presentation was slightly but significantly stimulated in primary cultured lacrimal gland acinar cells. However, exposure of cultured human corneal epithelial cells to IFN-γ more robustly increased expression and activity of cathepsin S in parallel with increased expression and function of MHC class II-mediated antigen presentation. We propose that early elevations in IFN-γ contribute to specific features of ocular disease pathology in Sjögren’s Syndrome.

The prevalence of ANA antibodies, anticentromere antibodies, and anti-cyclic citrullinated peptide antibodies in patients with primary Sjögren's syndrome compared to patients with dryness symptoms without primary Sjögren's syndrome confirmation

Objectives

Our study analyses the prevalence of ANA, anti-SS-A, anti-SS-B, and ACA and ACPA antibodies in patients with pSS and with dryness symptoms without pSS confirmation, and the association of ACPA and ACA antibodies with specific clinical symptoms.

Materials and methods

113 patients were divided into two groups: I – with diagnosed pSS (N = 75); and II – with dryness without pSS evidence (N = 38). Diagnostics: indirect immunofluorescence (IF; Hep-2 cell line) of antinuclear antibodies (ANA), anti-SS-A anti-SS-B antibodies determined with semi-quantitative method, autoantibody profile (14 antigens, ANA Profil 3 EUROLINE); basic laboratory, ophthalmic examination tests, minor salivary gland biopsy with focus score (FS), joint and lung evaluation, and ESSDAI questionnaire (pSS activity).

Results

88% of group I had ANA antibodies (1 : 320 titre), 5.3% at 1 : 160. Anti-SS-A antibodies were present in 88% of group I, including all ANA 1 : 160. Anti-SS-A antibodies positively correlated with greater and moderate activity of ESSDAI 5 (p = 0.046) and FS. The presence of SS-B antibodies significantly affected disease activity. ACPA present: group I – 13% (associated with higher arthritis incidence; p = 0.003); group II – 8%. ACA antibodies present in 4% of group I, but not in group II. No ACA association with interstitial lung changes (small ACA + group excludes full conclusions).

Conclusions

ANA antibodies should also be considered in a titre of less than 1 : 320, but the presence of anti-SS-A antibodies is still the most important immunological marker for pSS. Anti-SS-A antibodies correlate with higher disease activity (ESSDAI ≥ 5) and higher FS. The presence of the anti-SS-B antibody was significantly affected by higher activity of the disease. The incidence of arthritis was higher in patients with ACPA+ pSS compared to ACPA– (p = 0.003). There was no relationship between ACPA and arthritis in patients with dry-type syndrome without diagnosis of pSS.