CD4−CD8− T-cells in primary Sjögren's syndrome: Association with the extent of glandular involvement

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.

Double-Negative T (DNT) Cells in Patients with Systemic Lupus Erythematosus

Double-negative T (DNT) cells are a rare and unconventional T-lymphocyte subpopulation lacking both CD4 and CD8 markers. Their immunopathological roles and clinical relevance have yet to be elucidated. Beyond autoimmune lymphoproliferative syndrome (ALPS), these cells may also play a role in rheumatic disorders, including systemic lupus erythematosus (SLE); indeed, these two diseases share several autoimmune manifestations (including nephritis). Moreover, one of the main experimental murine models used to investigate lupus, namely the MRL/lpr mouse, is characterized by an expansion of DNT cells, which can support the production of pathogenic autoantibodies and/or modulate the immune response in this context. However, lupus murine models are not completely consistent with their human SLE counterpart, of course. In this mini review, we summarize and analyze the most relevant clinical studies investigating the DNT cell population in SLE patients. Overall, based on the present literature review and analysis, DNT cell homeostasis seems to be altered in patients with SLE. Indeed, most of the available clinical studies (which include both adults and children) reported an increased DNT cell percentage in SLE patients, especially during the active phases, even though no clear correlation with disease activity and/or inflammatory parameters has been clearly established. Well-designed, standardized, and longitudinal clinical studies focused on DNT cell population are needed, in order to further elucidate the actual contribution of these cells in SLE pathogenesis and their interactions with other immune cells (also implicated and/or altered in SLE, such as basophils), and clarify whether their expansion and/or immunophenotypic aspects may have any immunopathological relevance (and, then, represent potential disease markers and, in perspective, even therapeutic targets) or are just an unspecific epiphenomenon of autoimmunity.

Understanding the Spectrum of Immune Dysregulation Manifestations in Autoimmune Lymphoproliferative Syndrome and Autoimmune Lymphoproliferative Syndrome-like Disorders

As a disorder of immune dysregulation, autoimmune lymphoproliferative syndrome (ALPS) stems from pathogenic variants in the first apoptosis signal-mediated apoptosis (Fas) and Fas-ligand pathway that result in elevations of CD3+ TCRαβ+ CD4- CD8- T cells along with chronic lymphoproliferation, a heightened risk for malignancy, and importantly for the rheumatologist, increased risk of autoimmunity. While immune cytopenias are the most encountered autoimmune phenomena, there is increasing appreciation for ocular, musculoskeletal, pulmonary and renal inflammatory manifestations similar to more common rheumatology diseases. Additionally, ALPS-like conditions that share similar clinical features and opportunities for targeted therapy are increasingly recognized via genetic testing, highlighting the need for rheumatologists to be facile in the recognition and diagnosis of this spectrum of disorders. This review will focus on clinical and laboratory features of both ALPS and ALPS-like disorders with the intent to provide a framework for rheumatologists to understand the pathophysiologic drivers and discriminate between diagnoses.

Autoimmune lymphoproliferative syndrome: A disorder of immune dysregulation

Autoimmune Lymphoproliferative Syndrome (ALPS) is an autoimmune disease that has been reported in over 2200 patients. It is a rare, genetic disease where pathogenic variants occur in the extrinsic pathway of apoptosis. Various mutations in different genes, such as FAS, FASL, and CASP10, can result in ALPS. Most commonly, pathogenic variants occur in the FAS receptor. This malfunctioning pathway allows for the abnormal accumulation of lymphocytes, namely CD3 + TCRαβ+CD4 - CD8- (double negative (DN) T) cells, which are a hallmark of the disease. This disease usually presents in childhood with lymphadenopathy and splenomegaly as a result of lymphoproliferation. Over time, these patients may develop cytopenias or lymphomas because of irregularities in the immune system. Current treatments include glucocorticoids, mycophenolate mofetil, sirolimus, immunoglobulin G, and rituximab. These medications serve to manage the symptoms and there are no standardized recommendations for the management of ALPS. The only curative therapy is a bone marrow transplant, but this is rarely done because of the complications. This review serves to broaden the understanding of ALPS by discussing the mechanism of immune dysregulation, how the symptoms manifest, and the mechanisms of treatment. Additionally, we discuss the epidemiology, comorbidities, and medications relating to ALPS patients across the United States using data from Cosmos.

Analyzation of the Peripheral Blood Mononuclear Cells Atlas and Cell Communication of Rheumatoid Arthritis Patients Based on Single-Cell RNA-Seq

Background

Rheumatoid arthritis (RA) is a common chronic inflammatory autoimmune disease with a multifactorial etiology. Peripheral blood is the main channel of the immune system, and peripheral blood mononuclear cells (PBMCs) are the immune cells that initiate the autoimmune inflammatory process. However, there are few reports on the mechanisms of peripheral blood immunity in RA.

Methods

ScRNA-seq was performed on four RA samples and integrated with single-cell transcriptome data from four healthy control samples downloaded from publicly available databases for analysis.

Results

A total of 52,073 cells were used for descending clustering analysis to map RA peripheral blood immune cells at single-cell resolution. Redimensional clustering analysis of four major immune cells (T cells, monocytes, B cells, and natural killer cells) revealed that double-negative T (DNT) cells were significantly altered in abundance and function. And a number of genes (including SOCS3, cAMP-responsive element modulator (CREM), B2M, MTFP1, RSRP1, and YWHAB) were specifically downregulated in DNT cells. RA T cells, especially DNT cells, exhibit significant metabolic defects and dysfunction, mainly in the form of inhibition of oxidative phosphorylation, ATP synthesis, and major histocompatibility complex (MHC)-I-mediated antigen presentation. In addition, cellular communication networks were established, and it was evident that RA is significantly attenuated in the number and intensity of cellular communication. Monocytes and T cells play key roles in the process of the immune inflammatory response through CCL and MHC-related pathways.

Conclusions

This study describes the landscape of the peripheral blood immune system and cell communication in RA, characterizes the abundance of PBMCs, gene expression profiles, and changes in signaling pathways in RA patients, and identifies several key cell subpopulations (DNT and classic monocytes) and specific genes (SOCS3, CREM, B2M, MTFP1, RSRP1, and YWHAB). Meanwhile, we propose that classic monocytes in peripheral blood may migrate to sites of inflammation in synovial tissue under the chemotaxis of the chemokines CCL3 and CCL3L1, differentiate into macrophages, secrete proinflammatory cytokines, and thus participate in the inflammatory response. These findings provide new insights for the future elucidation of the peripheral blood immune mechanisms of RA and the search for new clinical therapeutic targets.

Low-dose interleukin-2 can improve salivary secretion but not lymphocyte infiltration of salivary glands in a murine model of Sjögren’s syndrome

Introduction/aim

Effects of low-dose interleukin-2 (IL-2) on the exocrine glandular glands of Sjögren’s syndrome are unknown. The aim of this study was to investigate the effects of low-dose IL-2 on salivary gland structure and function in a murine model of Sjögren’s syndrome.

Materials and methods

Non-obese diabetic/Ltj (NOD) mice were used as the animal model of Sjögren’s syndrome, and low-dose IL-2 or phosphate buffered saline was administered subcutaneously from 5 weeks of age, while ICR mice were used as controls. Some mice were sacrificed at 9 weeks of age, while the other mice that continued to receive treatment were sacrificed at 23 weeks. We determined the salivary flow rate of mice every 3 weeks during the intervention. After the mice were sacrificed, one submandibular gland was removed for pathological evaluation, while the other submandibular gland was used to measure the levels of 25 cytokines by Luminex technology. Cervical lymph nodes and spleens were examined by flow cytometry for the proportions of CD8⁺ T cells and Treg cells.

Results

The results showed that the salivary flow rate of NOD mice was slower than that of control-group mice, and there were more pathological changes in the submandibular gland. The levels of many cytokines in the submandibular gland were elevated. The proportion of CD8⁺ T cells in the cervical lymph nodes and spleens was increased; however, the proportion of Treg cells was decreased. After treatment with IL-2, the exocrine function of the salivary glands of mice was improved. IL-2 also promoted the proliferation of Treg cells in the cervical lymph nodes and spleens, but it did not alter the extent of lymphocyte infiltration in the submandibular gland. The levels of cytokines in the submandibular glands, as well as the proportion of CD8⁺ T cells in the cervical lymph nodes and spleens, were unchanged significantly after IL-2 treatment.

Conclusion

Our results demonstrate that treatment with low-dose IL-2 improves the secretory function of the exocrine glands of mice with Sjögren’s syndrome, but it does not reverse the structural damage of the exocrine glands.

TCRαβ+ CD4-/CD8- "double negative" T cells in health and disease-implications for the kidney

Double negative (DN) T cells, one of the least studied T lymphocyte subgroups, express T cell receptor αβ but lack CD4 and CD8 coreceptors. DN T cells are found in multiple organs including kidney, lung, heart, gastrointestinal tract, liver, genital tract, and central nervous system. DN T cells suppress inflammatory responses in different disease models including experimental acute kidney injury, and significant evidence supports an important role in the pathogenesis of systemic lupus erythematosus. However, little is known about these cells in other kidney diseases. Therefore, it is important to better understand different functions of DN T cells and their signaling pathways as promising therapeutic targets, particularly with the increasing application of T cell-directed therapy in humans. In this review, we aim to summarize studies performed on DN T cells in normal and diseased organs in the setting of different disease models with a focus on kidney.

CD3+CD4-CD8- (Double-Negative) T Cells in Inflammation, Immune Disorders and Cancer

The crucial role of CD4⁺ and CD8⁺ T cells in shaping and controlling immune responses during immune disease and cancer development has been well established and used to achieve marked clinical benefits. CD3⁺CD4^-CD8^- double-negative (DN) T cells, although constituting a rare subset of peripheral T cells, are gaining interest for their roles in inflammation, immune disease and cancer. Herein, we comprehensively review the origin, distribution and functions of this unique T cell subgroup. First, we focused on characterizing multifunctional DN T cells in various immune responses. DN regulatory T cells have the capacity to prevent graft-versus-host disease and have therapeutic value for autoimmune disease. T helper-like DN T cells protect against or promote inflammation and virus infection depending on the specific settings and promote certain autoimmune disease. Notably, we clarified the role of DN tumor-infiltrating lymphocytes and outlined the potential for malignant proliferation of DN T cells. Finally, we reviewed the recent advances in the applications of DN T cell-based therapy for cancer. In conclusion, a better understanding of the heterogeneity and functions of DN T cells may help to develop DN T cells as a potential therapeutic tool for inflammation, immune disorders and cancer.

Therapeutic Potential of Anti-Interferon α Vaccination on SjS-Related Features in the MRL/lpr Autoimmune Mouse Model

Sjögren’s syndrome (SjS) is a frequent systemic autoimmune disease responsible for a major decrease in patients’ quality of life, potentially leading to life-threatening conditions while facing an unmet therapeutic need. Hence, we assessed the immunogenicity, efficacy, and tolerance of IFN-Kinoid (IFN-K), an anti-IFNα vaccination strategy, in a well-known mouse model of systemic autoimmunity with SjS-like features: MRL/MpJ-Faslpr/lpr (MRL/lpr) mice. Two cohorts (with ISA51 or SWE01 as adjuvants) of 26 female MRL/lpr were divided in parallel groups, “controls” (not treated, PBS and Keyhole Limpet Hemocyanin [KLH] groups) or “IFN-K” and followed up for 122 days. Eight-week-old mice received intra-muscular injections (days 0, 7, 28, 56 and 84) of PBS, KLH or IFN-K, emulsified in the appropriate adjuvant, and blood samples were serially collected. At sacrifice, surviving mice were euthanized and their organs were harvested for histopathological analysis (focus score in salivary/lacrimal glands) and IFN signature evaluation. SjS-like features were monitored. IFN-K induced a disease-modifying polyclonal anti-IFNα antibody response in all treated mice with high IFNα neutralization capacities, type 1 IFN signature’s reduction and disease features’ (ocular and oral sicca syndrome, neuropathy, focus score, glandular production of BAFF) improvement, as reflected by the decrease in Murine Sjögren’s Syndrome Disease Activity Index (MuSSDAI) modelled on EULAR Sjögren’s Syndrome Disease Activity Index (ESSDAI). No adverse effects were observed. We herein report on the strong efficacy of an innovative anti-IFNα vaccination strategy in a mouse model of SjS, paving the way for further clinical development (a phase IIb trial has just been completed in systemic lupus erythematosus with promising results).

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.

Presentation and diagnosis of autoimmune lymphoproliferative syndrome (ALPS)

INTRODUCTION

Autoimmune lymphoproliferative syndrome (ALPS) is a rare disorder of immune dysregulation characterized by derangements in first apoptosis signal-mediated apoptosis and elevations in CD3⁺TCRαβ⁺CD4^-CD8^- 'double negative' T cells. As our understanding of this pleomorphic disorder expands, the importance of molecular diagnosis is ever more apparent due to the growing number of disorders that may present with overlapping initial symptoms, but for which there is an ever-increasing list of therapeutic options.

AREAS COVERED

This review will cover the current understanding of the molecular biology and pathophysiology of ALPS as well as describe some of the overlapping syndromes in order to better demonstrate the importance of establishing the correct diagnosis.

EXPERT OPINION

Going forward, international, multicenter collaboration to fully characterize ALPS and the ALPS-like disorders, including with particular focus on defining the defects for those patients with undefined ALPS, is important to both continue to improve our understanding of this disorder and to drive patient care forward to provide the best outcomes. Additionally, it is probably time to re-convene an international expert panel to re-define diagnostic criteria taking into consideration the most recent available data in order to optimize patient care.

Transcriptome landscape of double negative T cells by single-cell RNA sequencing

CD4 and CD8 coreceptor double negative TCRαβ⁺ T (DNT) cells are increasingly being recognized for their critical and diverse roles in the immune system. However, their molecular and functional signatures remain poorly understood and controversial. Moreover, the majority of studies are descriptive because of the relative low frequency of cells and non-standardized definition of this lineage. In this study, we performed single-cell RNA sequencing on 28,835 single immune cells isolated from mixed splenocytes of male C57BL/6 mice using strict fluorescence-activated cell sorting. The data was replicated in a subsequent study. Our analysis revealed five transcriptionally distinct naïve DNT cell clusters, which expressed unique sets of genes and primarily performed T helper, cytotoxic and innate immune functions. Anti-CD3/CD28 activation enhanced their T helper and cytotoxic functions. Moreover, in comparison with CD4⁺, CD8⁺ T cells and NK cells, Ikzf2 was highly expressed by both naïve and activated cytotoxic DNT cells. In conclusion, we provide a map of the heterogeneity in naïve and active DNT cells, addresses the controversy about DNT cells, and provides potential transcription signatures of DNT cells. The landscape approach herein will eventually become more feasible through newer high throughput methods and will enable clustering data to be fed into a systems analysis approach. Thus the approach should become the "backdrop" of similar studies in the myriad murine models of autoimmunity, potentially highlighting the importance of DNT cells and other minor lineage of cells in immune homeostasis. The clear characterization of functional DNT subsets into helper DNT, cytotoxic DNT and innate DNT will help to better understand the intrinsic roles of different functional DNT subsets in the development and progression of autoimmune diseases and transplant rejection, and thereby may facilitate diagnosis and therapy.

Double-negative T cells in autoimmune diseases

PURPOSE OF REVIEW

TCRαβ+CD4-CD8- double-negative T (DNT) cells, a principal subset of mature T lymphocytes, have been closely linked with autoimmune/inflammatory conditions. However, controversy persists regarding their ontogeny and function. Here, we present an overview on DNT cells in different autoimmune diseases to advance a deeper understanding of the contribution of this population to disease pathogenesis.

RECENT FINDINGS

DNT cells have been characterized in various chronic inflammatory diseases and they have been proposed to display pathogenic or regulatory function. The tissue location of DNT cells and the effector cytokines they produce bespeak to their active involvement in chronic inflammatory diseases.

SUMMARY

By producing various cytokines, expanded DNT cells in inflamed tissues contribute to the pathogenesis of a variety of autoimmune inflammatory diseases. However, it is unclear whether this population represents a stable lineage consisting of different subsets similar to CD4+ T helper cell subset. Better understanding of the possible heterogeneity and plasticity of DNT cells is needed to reveal interventional therapeutic opportunities.

New frontiers in precision medicine for Sjogren's syndrome

Introduction: Sjögren's syndrome is a unique systemic autoimmune disease, placed in the center of systemic autoimmunity and at the crossroads of autoimmunity and lymphoproliferation. The diverse clinical picture of the disease, the inefficacy of current biologic treatments, and the co-existence with lymphoma conferring to the patients' morbidity and mortality force the scientific community to review disease pathogenesis and reveal the major implicated cellular and molecular elements.Areas covered: Biomarkers for early diagnosis, prediction, stratification, monitoring, and targeted treatments can serve as a tool to interlink and switch from the clinical phenotyping of the disease into a more sophisticated classification based on the underlying critical molecular pathways and endotypes. Such a transition may define the establishment of the so-called precision medicine era in which patients' management will be based on grouping according to pathogenetically related biomarkers. In the current work, literature on Sjogren's syndrome covering several research fields including clinical, translational, and basic research has been reviewed.Expert opinion: The perspectives of clinical and translational research are anticipated to define phenotypic clustering of high-risk pSS patients and link the clinical picture of the disease with fundamental molecular mechanisms and molecules implicated in pathogenesis.

CD4 derived double negative T cells prevent the development and progression of nonalcoholic steatohepatitis

Hepatic inflammation is the driving force for the development and progression of NASH. Treatment targeting inflammation is believed to be beneficial. In this study, adoptive transfer of CD4+ T cells converted double negative T cells (cDNT) protects mice from diet-induced liver fat accumulation, lobular inflammation and focal necrosis. cDNT selectively suppress liver-infiltrating Th17 cells and proinflammatory M1 macrophages. IL-10 secreted by M2 macrophages decreases the survival and function of cDNT to protect M2 macrophages from cDNT-mediated lysis. NKG2A, a cell inhibitory molecule, contributes to IL-10 induced apoptosis and dampened suppressive function of cDNT. In conclusion, ex vivo-generated cDNT exert potent protection in diet induced obesity, type 2 diabetes and NASH. The improvement of outcome is due to the inhibition on liver inflammatory cells. This study supports the concept and the feasibility of potentially utilizing this autologous immune cell-based therapy for the treatment of NASH.

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.

Contributions of Major Cell Populations to Sjögren's Syndrome

Sjögren’s syndrome (SS) is a female dominated autoimmune disease characterized by lymphocytic infiltration into salivary and lacrimal glands and subsequent exocrine glandular dysfunction. SS also may exhibit a broad array of extraglandular manifestations including an elevated incidence of non-Hodgkin’s B cell lymphoma. The etiology of SS remains poorly understood, yet progress has been made in identifying progressive stages of disease using preclinical mouse models. The roles played by immune cell subtypes within these stages of disease are becoming increasingly well understood, though significant gaps in knowledge still remain. There is evidence for distinct involvement from both innate and adaptive immune cells, where cells of the innate immune system establish a proinflammatory environment characterized by a type I interferon (IFN) signature that facilitates propagation of the disease by further activating T and B cell subsets to generate autoantibodies and participate in glandular destruction. This review will discuss the evidence for participation in disease pathogenesis by various classes of immune cells and glandular epithelial cells based upon data from both preclinical mouse models and human patients. Further examination of the contributions of glandular and immune cell subtypes to SS will be necessary to identify additional therapeutic targets that may lead to better management of the disease.

Role of CD 20+ T cells and related cytokines in mediating retinal microvascular changes and ocular complications in chronic-plaque type psoriasis

OBJECTIVE

To assess the role of CD3⁺ CD20⁺ CD4^- CD8^- double-negative (DN) or CD3⁺CD20⁺ CD4/CD8⁺ T cells and the related pro-inflammatory cytokines in the humor aqueous, in mediating retinal microvascular changes in patients with chronic plaque-type moderate to severe psoriasis.

DESIGN

A total of 76 patients (57.6 ± 11.7 years) with chronic plaque-type psoriasis were initially evaluated. Nineteen patients (19 eyes) and 19 healthy volunteers (19 eyes) were subjected to dermatological evaluation with Psoriasis Area Severity Index (PASI) and the Dermatology life quality index (DLQI). Retinal images were processed using an automatized software. On the same day, a venous sample was collected and analyzed using multiparametric flow cytometry. Three out of 6 patients who presented cataract, consented to perform surgery with humor aqueous collection. The samples were analyzed using a Multi-Analyte ELISA kit for the simultaneous quantification of IL1α, IL1β, IL2, IL4, IL6, IL8, IL10, IL12, IL17A, IFNγ, TNF-α, GMCSF.

RESULTS

The CD3⁺CD4⁺/CD8⁺CD20⁺CD56^- T cells expression was greater in the psoriatic patients (+73.9%, P < 0.001) compared to controls, but not the DN T cells (-8.2%, P = 0.30). Ocular complications were diagnosed in 61.1% of patients, microvascular parameters including artero-venous ratio (P = 0.04), subfoveal choriocapillaris/Sattler's layer, and choroidal thickness (CT, both P < 0.001) were significantly altered in psoriasis subgroup. The increased circulating levels of the CD3⁺CD4⁺/CD8⁺CD20⁺CD56^- T cells were associated with thinning of subfoveal CT (P = 0.03) and Haller's layer (P = 0.01). Instead, the DN T cells presented an inverse relationship with disease duration (P = 0.02), DLQI score (P = 0.02), and the use of biological therapy (P = 0.05). The related cytokine patterns possibly modified in this cellular context have been investigated. No significant differences were observed in cytokines levels between psoriasis and controls, the most significant difference was detected on IL-6, without reaching statistical significance (fold change of 1.4, P = 0.13).

CONCLUSION

Our findings demonstrated that CD20⁺ T cell subpopulation is highly represented in psoriasis regardless of the use of immunomodulatory therapies, and the diffuse microvascular alterations suggested possible endothelial damage as mainstream for the genesis of psoriatic-mediated complications as further supported by the comparable concentrations of cytokines, at least as humor aqueous content, with respect to healthy eyes.

Alteration of liver-infiltrated and peripheral blood double-negative T-cells in primary biliary cholangitis

BACKGROUND & AIMS

Double-negative (DN) T-cell is a unique regulatory T-cell, which is essential for maintaining immune system homoeostasis. However, the role of DN T-cells in the pathogenesis of primary biliary cholangitis (PBC) is still unknown.

METHODS

We investigated the number and function of DN T-cells in peripheral blood and liver biopsy specimens of PBC patients.

RESULTS

The number and frequency of DN T-cells significantly decreased in peripheral blood and liver tissue of PBC patients. Furthermore, the frequency of DN T-cells in PBC was negatively correlated with disease severity and positively correlated with ursodeoxycholic acid response. In vitro assays showed that perforin expression and the suppressive capability of DN T-cells on the proliferation of CD4⁺ and CD8⁺ T-cells were impaired in PBC. Finally, lithocholic acid, the most hydrophobic acid, could downregulate the proliferation and perforin expression of DN T-cells.

CONCLUSIONS

Decreased quantity and function of DN T-cells in PBC may result in the loss of immune regulations on effector CD4⁺ and cytotoxic CD8⁺ T-cells, and thereby may break the immune tolerance and promote the pathogenesis of PBC.

IL-10-producing regulatory B cells restrain the T follicular helper cell response in primary Sjögren's syndrome

Increased numbers of T follicular helper (Tfh) cells have been implicated in the development of autoimmune diseases including primary Sjögren's syndrome (pSS), but how the Tfh cell response is regulated during autoimmune pathogenesis remains largely unclear. Here, we first found negative correlations between IL-10⁺ regulatory B (Breg) cell numbers and Tfh cell responses and disease activity in patients with pSS and mice with experimental Sjögren's syndrome (ESS). Moreover, we detected high expression of IL-10 receptor on Tfh cells and their precursors in both humans and mice. In culture, IL-10 suppressed human and murine Tfh cell differentiation by promoting STAT5 phosphorylation. By using an adoptive transfer approach and two-photon live imaging, we found significantly increased numbers of Tfh cells with enhanced T cell homing into B cell follicles in the draining cervical lymph nodes of RAG-2-/- mice transferred with IL-10-deficient B cells during ESS development compared with those of RAG-2-/- mice transferred with wild-type B cells. In ESS mice, CD19⁺CD1d^hiCD5⁺ Breg cells with decreased IL-10 production exhibited severely impaired suppressive effects on T cell proliferation. Consistently, CD19⁺CD24⁺CD38^hi Breg cells from pSS patients showed significantly reduced IL-10 production with defective inhibitory function in the suppression of autologous Tfh cell expansion. Furthermore, the adoptive transfer of IL-10-producing Breg cells markedly suppressed the Tfh cell response and ameliorated ESS progression in ESS mice. Together, these findings demonstrate a critical role for IL-10-producing Breg cells in restraining the effector Tfh cell response during pSS development.

Could Lymphocyte Profiling be Useful to Diagnose Systemic Autoimmune Diseases?

Considering the implications of B, T, and natural killer (NK) cells in the pathophysiology of systemic autoimmune diseases, the assessment of their distribution in the blood could be helpful for physicians in the complex process of determining a precise diagnosis. In primary Sjögren's syndrome, transitional and active naive B cells are increased and memory B cells are decreased compared to healthy controls and other systemic diseases. However, their utility to improve the accuracy of classification criteria has not been proven. In early untreated rheumatoid arthritis, proportions of regulatory T cells are constantly reduced, but other patterns are difficult to determine given the heterogeneity of published studies. In systemic lupus erythematosus, the lack of studies using large cohorts of patients and the diversity of the possible pathological mechanisms involved are also important impediments. Nevertheless, transitional B cell and plasma cell proportions are increased in most of the studies, the CD4/CD8 ratio is decreased, and the number of NK cells is reduced. Despite the low number of studies, anomalies of lymphocyte subset distribution was also described in ANCA-associated vasculitis, systemic scleroderma, and myositis. For now, flow cytometric analysis of lymphocyte subsets has focused mainly on specific subpopulations and is more useful for basic and translational research than for diagnostics in clinical practice. However, new modern methods such as mass cytometry and bioinformatics analyses may offer the possibility to simultaneously account for the relative proportions of multiple lymphocyte subsets and define a global profile in homogeneous groups of patients. The years to come will certainly incorporate such global lymphocyte profiling in reclassification of systemic autoimmune diseases.

Patients with Primary Sjögren's Syndrome Have Alterations in Absolute Quantities of Specific Peripheral Leucocyte Populations

An accurate dissection of peripheral blood enumeration is lacking in primary Sjögren's syndrome (pSS). The purpose of this study was to quantify different leucocyte populations in peripheral blood of patients with pSS. Numbers of specific leucocyte subsets were determined in 86 pSS patients and 74 healthy donors quantifying 21 distinct subtypes by flow cytometry. Subgroups of pSS patients were stratified based on presence of extraglandular manifestations (EGMs) and SSA/SSB autoantibodies. Overall, pSS patients manifested decreased lymphocyte subpopulations compared to healthy donors. Such decreases were more pronounced in SSA/SSB positive patients and patients with EGM. Granulocyte and monocyte subpopulations were increased in pSS patients compared to healthy donors, with the greatest increases in SSA/SSB positive patients. Unsupervised hierarchal clustering based on cell quantities was used to further subgroup the pSS patients into four clusters. One of the clusters characterized by higher concentrations of NKT cells, CD56hi NK cells, CD20⁺ CD38^- B cells and CD8⁺ CD38^- T cells was associated with weaker clinical symptoms than the other clusters, possibly marking a milder disease phenotype. In conclusion, our analyses indicate significant alterations in the cellular profiles of peripheral blood leucocytes in patients with pSS and may help to stratify the patients according to disease severity.

Proteasome inhibition suppresses Th17 cell generation and ameliorates autoimmune development in experimental Sjögren's syndrome

Immunoproteasome activation in immune cells is involved in the modulation of immune responses. Increasing evidence indicates that proteasome inhibitors show beneficial effects in treating autoimmune diseases, but it remains unclear whether proteasome inhibition is an effective approach for suppressing autoimmune development in Sjögren's syndrome (SS). Our previous work has demonstrated a critical role for Th17 cells in the development of experimental SS (ESS) in mice. In this study, we detected high levels of low-molecular-weight protein 7 (LMP7), a key subunit of the immunoproteasome, in Th17 cells from ESS mice. Moreover, treatment with bortezomib (BTZ), a proteasome inhibitor, markedly suppressed Th17 differentiation in both murine and human naive T cells in culture. Furthermore, ESS mice treated with BTZ displayed significantly higher saliva flow rates and a reduction in tissue destruction in the salivary glands compared with vehicle-treated ESS mice. Notably, BTZ-treated ESS mice showed markedly decreased Th17 cells, germinal center B cells and plasma cells in the peripheral lymphoid organs. In addition, adoptively transferred wild type naive CD4+ T cells rapidly differentiated into Th17 cells and induced salivary dysfunction in IL-17-deficient mice immunized for ESS induction. However, BTZ treatment profoundly suppressed the donor T-cell-derived Th17 response and ameliorated the reduction in salivary secretion in IL-17-deficient recipient mice. Taken together, our findings demonstrate that proteasome inhibition can effectively ameliorate ESS by suppressing the Th17 response, which may contribute to the development of a novel therapeutic strategy for the treatment of SS.Cellular &Molecular Immunology advance online publication, 10 July 2017; doi:10.1038/cmi.2017.8.

Clinical Efficacy and Safety of Total Glucosides of Paeony for Primary Sjögren's Syndrome: A Systematic Review

OBJECTIVE

To evaluate the clinical efficacy and safety of total glucosides of paeony (TGP) for primary Sjögren's syndrome (pSS).

METHODS

Eight electronic databases were searched from their inception to July 2016. Clinical randomized controlled trials (RCTs) were included. The study quality was evaluated according to the standard suggested in the Cochrane Handbook. RevMan 5.1 was used for statistical analysis.

RESULTS

Seven RCTs involving 443 patients were included. The results showed that TGP combined with an immunosuppressant (IS) showed greater efficacy for improving the saliva flow test of pSS compared to immunosuppressant alone (WMD -6.88, 95% CI -9.02 to -4.74, and P < 0.00001). And the same trend favouring TGP-IS dual combination was found in Schirmer test (WMD 1.63, 95% CI 0.26 to 3.01, and P = 0.02), ESR (WMD 7.33, 95% CI -10.08 to -4.59, and P < 0.00001), CRP (WMD -6.00, 95% CI -7.17 to -4.83, and P < 0.00001), IgM (WMD = -0.42, 95% CI -0.70 to 0.13, and P = 0.004), and IgG (WMD -3.22, 95% CI -4.32 to -2.12, and P < 0.00001) analysis. However, TGP did not affect IgA (WMD 0.53, 95% CI -1.34 to -0.29, and P = 0.20). The adverse events manifested no significant differences between the two groups.

CONCLUSIONS

The TGP-IS combination is superior to IS alone in the treatment of pSS. However, due to the low quality of included studies, high-quality RCTs are needed to confirm the beneficial effects of TGP.

Insight into pathogenesis of Sjögren's syndrome: Dissection on autoimmune infiltrates and epithelial cells

Sjögren's syndrome (SS) is a chronic autoimmune disease with broad clinical spectrum, extending from benign exocrinopathy to severe systemic disease and lymphoma development. The glandular and extraglandular dysfunction of SS is associated with lymphocytic infiltrates that invade the epithelial structures of affected organs. The in-depth study of autoimmune lesions in the minor salivary glands (MSG), which are the major target-organ of SS responses, revealed that the lymphocytic infiltrates vary in severity and composition among SS-patients, are full-blown at diagnosis and remain unchanged thereafter. Although the pathogenetic pathways underlying SS have not yet elucidated, it is well-established that glandular epithelial cells are central regulators of local autoimmune responses. Moreover, chronic inflammation affects epithelial function and phenotype, which strengthens or weakens their immunoregulatory/secretory function, leading to deterioration of autoimmune phenomena. Herein, the current findings regarding the autoimmune lesions, the role of epithelial cells and their interaction with infiltrating lymphocytic cells are discussed.

T cells and autoimmune kidney disease

Glomerulonephritis is traditionally considered to result from the invasion of the kidney by autoantibodies and immune complexes from the circulation or following their formation in situ, and by cells of the innate and the adaptive immune system. The inflammatory response leads to the proliferation and dysfunction of cells of the glomerulus, and invasion of the interstitial space with immune cells, resulting in tubular cell malfunction and fibrosis. T cells are critical drivers of autoimmunity and related organ damage, by supporting B-cell differentiation and antibody production or by directly promoting inflammation and cytotoxicity against kidney resident cells. T cells might become activated by autoantigens in the periphery and become polarized to secrete inflammatory cytokines before entering the kidney where they have the opportunity to expand owing to the presence of costimulatory molecules and activating cytokines. Alternatively, naive T cells could enter the kidney where they become activated after encountering autoantigen and expand locally. As not all individuals with a peripheral autoimmune response to kidney antigens develop glomerulonephritis, the contribution of local kidney factors expressed or produced by kidney cells is probably of crucial importance. Improved understanding of the biochemistry and molecular biology of T cells in patients with glomerulonephritis offers unique opportunities for the recognition of treatment targets for autoimmune kidney disease.

Effect of Tobacco Smoking on The Clinical, Histopathological, and Serological Manifestations of Sjögren's Syndrome

Objectives

To assess the association of smoking habits with the clinical, serological, and histopathological manifestations of Sjögren’s syndrome (SS) and non-Sjögren’s sicca (non-SS sicca).

Methods

Cross-sectional case-control study of 1288 patients with sicca symptoms (587 SS and 701 non-SS sicca) evaluated in a multi-disciplinary research clinic. Smoking patterns were obtained from questionnaire data and disease-related clinical and laboratory data were compared between current, past, ever, and never smokers.

Results

Current smoking rates were 4.6% for SS patients compared to 14.1% in non-SS sicca (p = 5.17x10E-09), 18% in a local lupus cohort (p = 1.13x10E-14) and 16.8% in the community (p = 4.12x10E-15). Current smoking was protective against SS classification (OR 0.35, 95%CI 0.22–0.56, FDR q = 1.9E10-05), focal lymphocytic sialadenitis (OR 0.26, 95%CI 0.15–0.44, FDR q = 1.52x10E-06), focus score ≥1 (OR 0.22, 95%CI 0.13–0.39, FDR q = 1.43x10E-07), and anti-Ro/SSA(+) (OR 0.36, 95%CI 0.2–0.64, FDR q = 0.0009); ever smoking was protective against the same features and against anti-La/SSB(+) (OR 0.52, 95%CI 0.39–0.70, FDR q = 5.82x10E-05). Duration of smoking was inversely correlated with SS even after controlling for socioeconomic status, BMI, alcohol and caffeine consumption.

Conclusions

Current tobacco smoking is negatively and independently associated with SS, protecting against disease-associated humoral and cellular autoimmunity. The overall smoking rate amongst SS patients is significantly lower than in matched populations and the effects of smoking are proportional to exposure duration.

In spite of the protective effects of tobacco on SS manifestations, it is associated with other serious comorbidities such as lung disease, cardiovascular risk and malignancy, and should thus be strongly discouraged in patients with sicca.

Present and future of biologic drugs in primary Sjögren's syndrome

INTRODUCTION

Primary Sjögren's (pSS) syndrome is a chronic, autoimmune, and systemic disease characterized by xerostomia, xerophthalmia, muscle pain and fatigue. The disease may be complicated by a systemic involvement, such as a pulmonary fibrosis or the development of lymphoma which severely worsens the prognosis. Actually, there are no recommendations for the management of pSS. However, recent advances in the understanding of its pathogenesis have uncovered some pathways that have potential as therapeutic targets. Areas covered: In this review, the authors present the biologic drugs potentially valuable to the treatment of pSS in light of its physiopathology with a 'bird's eye' view of future prospects. The authors took into account relevant studies published from 2004 to 2016. Expert opinion: Biological treatment in pSS is a promising opportunity to potentially control disease activity and prevent its complication. Currently, inhibition of B-cell and IL-17 pathways seem to be the most promising avenues. New achievements in the knowledge of pSS pathophysiology are necessary in order to try to simultaneously predict the predominant pathogenic pathway, the kind of patients at major risk to develop a more severe disease, and the appropriate biological therapy to use.

Autoimmunity in 2014

Our PubMed search for peer-reviewed articles published in the 2014 solar year retrieved a significantly higher number of hits compared to 2013 with a net 28 % increase. Importantly, full articles related to autoimmunity constitute approximately 5 % of immunology articles. We confirm that our understanding of autoimmunity is becoming a translational paradigm with pathogenetic elements rapidly followed by new treatment options. Furthermore, numerous clinical and pathogenetic elements and features are shared among autoimmune diseases, and this is well illustrated in the recent literature. More specifically, the past year witnessed critical revisions of our understanding and management of antiphospholipid syndrome with new exciting data on the pathogenicity of the serum anti-beta2 glycoprotein autoantibody, a better understanding of the current and new treatments for rheumatoid arthritis, and new position papers on important clinical questions such as vaccinations in patients with autoimmune disease, comorbidities, or new classification criteria. Furthermore, data confirming the important connections between innate immunity and autoimmunity via toll-like receptors or the critical role of T regulatory cells in tolerance breakdown and autoimmunity perpetuation were also reported. Lastly, genetic and epigenetic data were provided to confirm that the mosaic of autoimmunity warrants a susceptible individual background which may be geographically determined and contribute to the geoepidemiology of diseases. The 2014 literature in the autoimmunity world should be cumulatively regarded as part of an annus mirabilis in which, on a different level, the 2014 Annual Meeting of the American College of Rheumatology in Boston was attended by over 16,000 participants with over selected 3000 abstracts.

Update on the immunobiology of Sjögren's syndrome

PURPOSE OF REVIEW

The purpose of this review is to give an update on the understanding of the immune responses involved in the pathogenesis of primary Sjögren's syndrome (pSS), and to highlight recent findings on the underlying molecular and cellular mechanisms at play.

RECENT FINDINGS

In recent years, genetic studies have confirmed the importance of aberrant type I interferon (IFN) and B cell responses in pSS and highlighted critical pathways involved in disease pathogenesis. In particular, the formation of ectopic lymphoid structures has emerged as an important factor in the establishment of chronic autoimmune responses in target organs. Interestingly, recent studies on viral infection in the context of pSS, as well as findings on the contribution of salivary gland epithelial cells in local immune responses, offer further clues to understand pSS etiology and its target organ specificity. Finally, new evidence brings T cells and natural killer cells under renewed attention as possible important contributors to pSS pathogenesis.

SUMMARY

Progress made during the last few years on the pathogenesis of pSS has been mirrored by clinical trials directed at inhibiting cytokines, B, or T cell responses. Future efforts should focus on identifying additional pSS specific targets and developing methods to help choose optimal therapeutic strategies for the individual patient.

Double-negative T resident memory cells of the lung react to influenza virus infection via CD11c(hi) dendritic cells

Immunity to Influenza A virus (IAV) is controlled by conventional TCRαβ(+) CD4(+) and CD8(+) T lymphocytes, which mediate protection or cause immunopathology. Here, we addressed the kinetics, differentiation, and antigen specificity of CD4(-)CD8(-) double-negative (DN) T cells. DNT cells expressed intermediate levels of TCR/CD3 and could be further divided in γδ T cells, CD1d-reactive type I NKT cells, NK1.1(+) NKT-like cells, and NK1.1(-) DNT cells. NK1.1(-) DNT cells had a separate antigen-specific repertoire in the steady-state lung, and expanded rapidly in response to IAV infection, irrespectively of the severity of infection. Up to 10% of DNT cells reacted to viral nucleoprotein. Reinfection experiments with heterosubtypic IAV revealed that viral replication was a major trigger for recruitment. Unlike conventional T cells, the NK1.1(-) DNT cells were in a preactivated state, expressing memory markers CD44, CD11a, CD103, and the cytotoxic effector molecule FasL. DNT cells resided in the lung parenchyma, protected from intravascular labeling with CD45 antibody. The recruitment and maintenance of CCR2(+) CCR5(+) CXCR3(+) NK1.1(-) DNT cells depended on CD11c(hi) dendritic cells (DCs). Functionally, DNT cells controlled the lung DC subset balance, suggesting they might act as immunoregulatory cells. In conclusion, we identify activation of resident memory NK1.1(-) DNT cells as an integral component of the mucosal immune response to IAV infection.

Salivary Gland Pathology in Sjögren's Syndrome

Primary Sjögren syndrome (pSS) can be considered a systemic autoimmune disease with a strong organ bias. The involvement of the exocrine glands is prevalent and drives the pathognomonic manifestations of dryness that define the sicca syndrome. The salivary glands also represent the hub of pSS pathology. Elements belonging to both innate and acquired immune responses have been described at this site that contribute to disease establishment and progression. The interaction between those elements and their relative contributions to the clinical manifestations and lymphoma progression largely remain to be addressed.

CXCR5 is critically involved in progression of lupus through regulation of B cell and double-negative T cell trafficking

The recruitment of immune cells to sites of tissue inflammation is orchestrated by chemokine/chemokine receptor networks. Among these, the CXCL13/CXCR5 axis is thought to be involved critically in systemic lupus erythematosus (SLE) and lupus nephritis pathogenesis. Beyond B cell abnormalities, another hallmark of SLE disease is the occurrence of aberrant T cell responses. In particular, double-negative (DN) T cells are expanded in the peripheral blood of patients with SLE and in lupus-prone mice. DN T cells induce immunoglobulin production, secrete proinflammatory cytokines and infiltrate inflamed tissue, including kidneys. We aimed to investigate how CXCR5 deficiency changes immune cell trafficking in murine lupus. We therefore crossed CXCR5(-/-) mice with B6/lpr mice, a well-established murine lupus model. B cell numbers and B cellular immune responses were diminished in CXCR5-deficient B6/lpr mice. In addition, we observed reduced accumulation of DN T cells in spleen and lymph nodes, paralleled by reduced splenomegaly and lymphadenopathy. In-vivo migration assays revealed reduced migration of CXCR5-deficient DN T cells into lymph nodes, and ex-vivo-activated CXCR5-deficient DN T cells failed to infiltrate kidneys of recipients. Moreover, DN T cells and B cells of CXCR5-deficient B6/lpr mice failed to migrate towards CXCL13 in vitro. We propose that CXCR5 is involved critically in B cell trafficking and germinal cell (GC) formation in murine lupus and in guiding pathogenic DN T cells into lymphoid organs and kidneys, and we therefore describe new pathomechanisms for the CXCL13/CXCR5 axis in SLE.

Interleukin (IL)-17-producing pathogenic T lymphocytes co-express CD20 and are depleted by rituximab in primary Sjögren's syndrome: a pilot study

Compelling evidence suggests that interleukin (IL)-17 and IL-17-producing cells play a pivotal role in the pathogenesis of primary Sjögren's syndrome (pSS). We investigated phenotypical and functional effects of the anti-CD20 antibody rituximab (RTX) on circulating and glandular IL-17-producing T cells in pSS. RTX is able to deplete glandular IL-17(+) CD3(+) CD4(-) CD8(-) double-negative (DN) and CD4(+) Th17 cells as well as circulating IL-17(+) DN T cells. A fraction of glandular and circulating IL-17(+) DN cells and CD4(+) T helper type 17 (Th17) cells co-expresses CD20 on the cell surface explaining, at least in part, such depletive capacity of RTX. The exposure to RTX does not rescue the in-vitro corticosteroid resistance of IL-17(+) DN T cells. Our results support further the therapeutic role in pSS of RTX that, despite its B cell specificity, appears able to also hamper IL-17-producing T cells in this disease.

Mobilization of lymphatic endothelial precursor cells and lymphatic neovascularization in primary Sjögren's syndrome

Although lymphatic neovascularization may be a key feature of chronic inflammation, it is almost unexplored in primary Sjögren's syndrome (pSS). A recent study revealed a pro‐lymphangiogenic function of interleukin (IL)‐17, a leading player in pSS pathogenesis. The aims of the study were to investigate lymphangiogenic mediators and lymphatic vasculature in pSS, as well as their possible association with IL‐17. Circulating lymphatic endothelial precursor cells (LEPCs) and Th17 cells were enumerated in pSS patients and healthy donors. VEGF‐C and IL‐17 levels were assessed in paired serum samples. Lymphatic vasculature, VEGF‐C/VEGF receptor (VEGFR)‐3 and IL‐17 were evaluated in pSS minor salivary glands (MSGs) and compared with normal and non‐specific chronic sialadenitis (NSCS) MSGs. Circulating LEPCs were expanded in pSS and correlated with circulating Th17 cells, IL‐17 and VEGF‐C. In pSS MSGs, a newly formed lymphatic capillary network was found within periductal inflammatory infiltrates and the number of interlobular lymphatic vessels was significantly increased compared with normal and NSCS MSGs. Strong VEGF‐C expression was detected in pSS ductal epithelial cells and periductal inflammatory cells. Numerous VEGFR‐3⁺ infiltrating mononuclear cells were exclusively observed in pSS MSGs. VEGFR‐3 expression was strongly increased in lymphatic capillaries of pSS MSGs. IL‐17⁺ inflammatory cells were preferentially observed around lymphatic vessels in pSS MSGs. This study supports the notion that lymphvasculogenesis and lymphangiogenesis are active in pSS, thereby unmasking a novel aspect of disease pathogenesis. In addition, our results suggest another possible pathogenic role of IL‐17 in pSS, further supporting its therapeutic targeting in this disease.

T Regulatory and T Helper 17 Cells in Primary Sjögren's Syndrome: Facts and Perspectives

Historically, primary Sjögren's syndrome (pSS) was thought to be a T helper (h) 1 driven disease due to the predominance of CD4(+)T lymphocytes and their products in target organs and peripheral blood of patients. In the last decades, the identification of a number of T cell subsets, including Th17, T regulatory (Treg), and follicular helper T cells, challenged this long-standing paradigm and prompted to identify their role in pSS pathogenesis. In addition the impact of abnormal proinflammatory cytokine production, such as IL-6, IL-17, IL-22, and IL-23, has also attracted considerable attention. However, although several studies have been carried out in experimental models and patients with pSS, many aspects concerning the role of Treg cells and IL-17/Th17 cell system in pSS pathogenesis are not fully elucidated. In particular, the role played by different IL-17-producing T cell subsets as well as the effects of pharmacological therapies on Treg/Th17 cell balance represents an intriguing issue. The aim of this review article is to provide an overview of current knowledge on Treg cells and IL-17-producing T cells in pSS pathogenesis. We believe that these insights into pSS pathogenesis may provide the basis for successful therapeutic intervention in this disease.

Programmed cell death 1 and Helios distinguish TCR-αβ+ double-negative (CD4-CD8-) T cells that derive from self-reactive CD8 T cells

TCR-αβ(+) double-negative (DN; CD4(-)CD8(-)) T cells represent a poorly understood cellular subset suggested to contribute to the pathogenesis of the autoimmune disease systemic lupus erythematosus. DN T cells have been proposed to derive from CD8(+) cells. However, the conditions that govern the loss of CD8 expression after Ag encounter are unknown. In this study, we tracked the fate of CD8 T cells from transgenic TCR mice exposed to their cognate Ags as self or in the context of infection. We demonstrate that CD8 T cells lose CD8 expression and become DN only when cognate Ag is sensed as self. This process is restricted to tissues where the Ag is present. We also show that DN T cells derived from self-reactive CD8 cells express the inhibitory molecules PD-1 and Helios. These molecules identify a subset of DN T cells in normal mice. A similar population expands when CD8 T cells from repertoires enriched in self-reactive cells (Aire-deficient) are transferred into cognate hosts. Collectively, our data suggest that a subset of DN T cells, identified by the expression of PD-1 and Helios, represent self-reactive cells. Our results provide an explanation for the origin of DN T cells and introduce CD8 loss as a process associated with self-Ag encounter.

Th17 cells in autoimmune diseases

Th17 cells are a new subset of CD4(+) T cells involved in the clearance of extracellular pathogens and fungi. Accumulating evidence suggests that Th17 cells and their signature cytokines have a pivotal role in the pathogenesis of multiple autoimmune-mediated inflammatory diseases. Here, we summarize recent research progress on Th17 function in the development and pathogenesis of autoimmune diseases. We also propose to identify new small molecule compounds to manipulate Th17 function for potential therapeutic application to treat human autoimmune diseases, including rheumatoid arthritis, systemic lupus erythematosus, Sjögren's syndrome, inflammatory bowel disease, and multiple sclerosis.

Fingolimod efficacy in multiple sclerosis associated with Sjogren syndrome

BACKGROUND

Sjogren syndrome (SS) is a common autoimmune disease characterized by lymphocytic infiltration of the exocrine glands with neurological involvement in about 20% of patients. The neurological manifestations in the central nervous system CNS may vary and include a multiple sclerosis (MS)-like disease, and the treatments with immunosuppressive drugs have been undertaken.

CASE PRESENTATION

We describe a case of 40-year-old woman with clinical and instrumental evidence of an MS characterized by numerous relapses and demyelinating lesions prevailing in the infratentorial and spinal cord. Immunological analysis showed biological data that were consistent with an SS. The treatment with fingolimod showed not only an optimal response to the demyelinating events but also biological parameters.

CONCLUSION

These data allow us to hypothesize possible combined efficacy of treatment with fingolimod in SS associated with definite MS.

Unmasking the pathogenic role of IL-17 axis in primary Sjögren's syndrome: a new era for therapeutic targeting?

Compelling evidence suggests that the IL-17 axis plays a pivotal role in the pathogenesis of several autoimmune disorders including primary Sjögren's syndrome (pSS). However, although several studies have been carried out in experimental models and patients with pSS, many aspects of this field are not fully elucidated. In particular, the role played by different Th17 cell subsets as well as the effects of pharmacological therapies on IL-17 balance represent an intriguing issue. Furthermore, the understanding of IL-17 axis pathogenic role in pSS may be of interest for therapeutic purposes as a variety of compounds targeting IL-17, IL-17 receptor and other related cytokines and transcription factors involved in Th17 cell commitment are under intense investigation. The aim of this review article is to provide an overview of current knowledge in IL-17/Th17 cells in pSS and discuss their potential therapeutic targeting in this disease.

Rituximab in primary Sjögren's syndrome: a ten-year journey

Primary Sjögren's syndrome (pSS) is an autoimmune disorder affecting exocrine glands and characterized in most cases by a rather mild clinical picture. However, a subgroup of pSS patients experience systemic extraglandular involvement leading to a worsening of disease prognosis. Current therapeutic options for the treatment of pSS are mainly empirical, often translated by other autoimmune diseases, and recent systematic reviews have highlighted the lack of evidence-based recommendations for most of the drugs commonly employed in the spectrum of extraglandular involvement. Because of the well-established role of B-lymphocytes in the pathogenesis of pSS, a B-cell targeting therapy may represent a new and intriguing therapeutic approach; in this context, growing evidence suggests that B-cell depletion by rituximab (RTX) is also effective in pSS. Of interest, besides clinical efficacy, RTX also showed biologic effects, consistently affecting the inflammation and the lymphoid organization that occur in target tissue. Moreover, the good results observed in the published trials after RTX treatment in pSS should represent the starting point to develop evidence-based guidelines for the use of biologic therapy in this disease.