The Clinical Relevance of IL-17-Producing CD4+CD161+ Cell and Its Subpopulations in Primary Sjögren's Syndrome

Study of pathogenic T-helper cell subsets in Asian Indian patients with Takayasu arteritis

The relapses and refractory disease are a challenge in the management of patients with Takayasu arteritis (TAK). We quantified pathogenic CD4 + memory T helper cells bearing surface markers CD161 and/or p-glycoprotein (MDR1) in patients with TAK. Peripheral blood mononuclear cells of 21 patients with TAK and 16 age-matched controls were stained with anti-CD3, anti-CD4, anti-CD45RA, anti-CD161 and anti-p-glycoprotein antibodies and subjected to flow cytometry by FACS ARIAIII. Eighteen patients underwent follow-up immunophenotyping. Intracellular staining for interleukin-17 and interferon-γ was performed for 18 patients and 11 controls. Surgical arterial biopsies of 6 TAK and 5 non-inflammatory controls were subjected to immunohistochemistry with anti-CD161 and anti-p-glycoprotein. At baseline the frequency of MDR1 + CD4 + and CD161 + MDR1 + CD4 + memory T cells was higher in TAK than controls (p = 0.002 and 0.01, respectively). After stimulation, the frequency of IFN-y + CD161 + cells was higher in TAK than controls (p = 0.028). Modal fluorescence intensity of CD161 + MDR1 + CD45RA - CD4 + cells was higher in active as compared with stable disease (p = 0.041). At 6 months, MDR1 + and CD161 + MDR1 + memory CD4 + T cells decreased significantly only in patients who had complete/partial response to treatment (p = 0.047 and 0.02, respectively). To conclude, MDR1 + and MDR1 + CD161 + CD4 + memory T-helper cells are increased in patients with TAK. These cells decreased only in patients with response to treatment during subsequent follow-up.

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.

The proportion of CD161 on CD56+ NK cells in peripheral circulation associates with clinical features and disease activity of primary Sjögren's syndrome

OBJECTIVES

The purpose of this study was to examine the proportion of CD161 on CD56+ natural killer (NK) cells in peripheral blood of primary Sjögren's syndrome (pSS) and investigate its clinical relevance of pSS.

METHODS

The proportion of CD56+ NK cells and CD161 on CD56+ NK cells was detected by flow cytometry in 31 pSS patients and 29 healthy controls (HCs). The correlations between the proportion of CD161+CD56+ NK cells and clinical features and disease activity of pSS were further analyzed. Meanwhile, we drew the receiver operating characteristic curve to evaluate the diagnostic value of CD161+CD56+ NK cells in pSS. In addition, we evaluated the differences in the effects of CD161+ cells and CD161- cells in peripheral blood on the function of CD56+ NK cells in 5 pSS patients.

RESULTS

The proportion of CD56+ NK cells and CD161+CD56+ NK cells decreased markedly in pSS patients compared to HCs. The correlation analysis showed that the proportion of CD161+CD56+ NK cells negatively correlated with white blood cells, Immunoglobulin A (IgA), IgM, IgG, European League Against Rheumatism Sjogren's Syndrome Patient Reported Index and European League Against Rheumatism Sjogren's Syndrome Disease Activity Index, and positively correlated with complement C4. The proportion of CD161+CD56+ NK cells in pSS patients with decayed tooth, fatigue, arthralgia, skin involvement, primary biliary cirrhosis, interstitial lung disease, anti-SSA/Ro60 positive, anti-SSB positive and high IgG was lower than that in negative patients. Furthermore, compared with inactive patients, the proportion of CD161+CD56+ NK cells decreased obviously in active patients. The area under the curve was 0.7375 (p = .0016), the results indicated that CD161+CD56+ NK cells had certain diagnostic values for pSS. In addition, the proportion of CD86, HLA-DR, Ki67, FasL, TNF-α, and IFN-γ on CD161+CD56+ NK cells was lower than that on CD161-CD56+ NK cells in the peripheral blood of pSS patients.

CONCLUSION

This study suggested that the proportion of CD56+ NK cells and CD161+CD56+ NK cells decreased significantly in pSS patients, and the proportion of CD161+CD56+ NK cells negatively associated with the clinical features and disease activity of pSS patients. CD161 expression inhibited the function of CD56+ NK cells in peripheral blood of pSS patients. The CD161+CD56+ NK cells may present as a potential target for therapy and a biomarker of disease activity in pSS.

Significance of N6-methyladenosine RNA methylation regulators in diagnosis and subtype classification of primary Sjögren's syndrome

The importance of N6-methyladenine (m6A) in mRNA metabolism, physiology, pathology and other life processes is well recognized. However, the exact role of m6A regulators in primary Sjögren's syndrome (PSS) remains unclear. In this study, we used bioinformatics and machine learning random forest approach to screen eight key m6A regulators from the Gene Expression Omnibus GSE7451, GSE40611 and GSE84844 datasets. An accurate nomogram model for predicting PSS risk was established based on these regulators. And using consensus clustering, patients diagnosed with PSS were classified into two different m6A patterns. We found that patients in group B had higher m6A scores compared to those in group A: furthermore, both groups were closely related to immunity and possibly to other diseases. These results emphasise the important role of m6A regulators in the pathogenesis of PSS. Our study of m6A patterns may inform future immunotherapy strategies for PSS.

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.

MICa/b-dependent activation of natural killer cells by CD64+ inflammatory type 2 dendritic cells contributes to autoimmunity

Primary Sjögren's syndrome (pSS) is an inflammatory autoimmune disorder largely mediated by type I and II interferon (IFN). The potential contribution of innate immune cells, such as natural killer (NK) cells and dendritic cells (DC), to the pSS pathology remains understudied. Here, we identified an enriched CD16+ CD56hi NK cell subset associated with higher cytotoxic function, as well as elevated proportions of inflammatory CD64+ conventional dendritic cell (cDC2) subtype that expresses increased levels of MICa/b, the ligand for the activating receptor NKG2D, in pSS individuals. Circulating cDC2 from pSS patients efficiently induced activation of cytotoxic NK cells ex vivo and were found in proximity to CD56+ NK cells in salivary glands (SG) from pSS patients. Interestingly, transcriptional activation of IFN signatures associated with the RIG-I/DDX60 pathway, IFN I receptor, and its target genes regulate the expression of NKG2D ligands on cDC2 from pSS patients. Finally, increased proportions of CD64hi RAE-1+ cDC2 and NKG2D+ CD11b+ CD27+ NK cells were present in vivo in the SG after poly I:C injection. Our study provides novel insight into the contribution and interplay of NK and cDC2 in pSS pathology and identifies new potential therapy targets.

Regulatory immune cells: a review of the novel paradigm of primary Sjogren's syndrome

Primary Sjögren's Syndrome (pSS) is an autoimmune disease that mostly affects women. Patients with pSS experience dry mouth and eyes in addition to signs of systemic disease. pSS was considered a Th1 autoimmune disease for many years. However, in various studies, it has been shown that dysregulation of regulatory cells play critical role in the pathogenesis of the disease. This review focuses on studies supporting this view and answers questions about the role of regulatory cells in the pathogenesis of pSS.

Utility of lymphocyte phenotype profile to differentiate primary Sjögren syndrome from Sicca syndrome

BACKGROUND

blood B cell profile has been proposed to have diagnostic utility in primary Sjögren syndrome (pSS), but the potential utility of advanced lymphocyte profiling to differentiate between pSS and Sicca syndrome has not been fully investigated.

METHODS

distribution of peripheral lymphocyte subpopulations was analysed by flow cytometry in 68 patients with pSS, 26 patients with Sicca syndrome and 23 healthy controls. The ability to discriminate between pSS and Sicca syndrome was analysed using the area under the curve (AUC) of the receiver operating characteristic curve of the different lymphocyte subsets.

RESULTS

the ratio between naïve/memory B cell proportions showed an AUC of 0.742 to differentiate pSS and Sicca syndrome, with a sensitivity of 76.6% and a specificity of 72% for a cut-off value of 3.4. The ratio of non-switched memory B cells to activated CD4+ T cells percentage (BNSM/CD4ACT) presented the highest AUC (0.840) with a sensitivity of 83.3% and specificity of 81.7% for a cut-off value < 4.1. To differentiate seronegative pSS patients from Sicca patients the BNSM/CD4ACT ratio exhibited an AUC of 0.742 (sensitivity 75%, specificity 66.7%, cut-off value < 4.4), and the number of naïve CD4 T cells had an AUC of 0.821 (sensitivity 76.9%, specificity 88.9%, cut-off value < 312/mm3).

CONCLUSION

patients with pSS show a profound imbalance in the distribution of circulating T and B lymphocytes subsets. The ratio BNSM/CD4ACT is useful to discriminate between pSS and Sicca syndrome.

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.

Unique Phenotypes and Functions of Follicular Helper T Cells and Regulatory T Cells in Sjögren's Syndrome

Sjogren’s syndrome (SS) is a T cell-mediated autoimmune disease of the systemic exocrine glands, such as salivary and lacrimal glands. A variety of T-cell subpopulations maintain immune tolerance in the thymus and periphery through complex immune responses including cellular and humoral immunity. The T-cell subpopulations exhibiting abnormal or unique phenotypes and impaired functionality have been reported to play important roles in the cellular mechanisms of autoimmunity in SS patients and animal models of SS. In this review, we focused on follicular helper T cells related to antibody production and regulatory T cells to control immune tolerance in the pathogenesis of SS. The unique roles of these T-cell subpopulations in the process of the onset or development of SS have been demonstrated in this review of recent publications. The clinical application of these T-cell subpopulations will be helpful for the development of new techniques for diagnosis or treatment of SS in the future.

MicroRNA in Sjögren's Syndrome: Their Potential Roles in Pathogenesis and Diagnosis

Sjögren's syndrome (SS) or sicca syndrome was described by Swedish ophthalmologist Sjögren in the year 1933 for the first time. The etiology of the SS is multifunctional and includes a combination of genetic predisposition and environmental as well as epigenetic factors. It is an autoimmune disease characterized by features of systemic autoimmunity, dysfunction, and inflammation in the exocrine glands (mainly salivary and lacrimal glands) and lymphocytic infiltration of exocrine glands. In fact, the involvement of lacrimal and salivary glands results in the typical features of dry eye and salivary dysfunction (xerostomia). Only in one-third of the patients also present systemic extraglandular manifestations. T cells were originally considered to play the initiating role in the autoimmune process, while B cells were restricted to autoantibody production. In recent years, it is understood that the roles of B cells are multiple. Moreover, autoantibodies and blood B cell analysis are major contributors to a clinical diagnosis of Sjögren's syndrome. Recently, there has been rising interest in microRNA implication in autoimmunity. Unfortunately, to date, there are only a few studies that have investigated their participation in SS etiopathogenesis. The purpose of this work is to gather the data present in the literature to clarify this complex topic.

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.

Clinical relevance of RORγ positive and negative subsets of CD161+CD4+ T cells in primary Sjögren's syndrome

OBJECTIVE

The relevance of the Th17 pathway in primary SS (pSS) is unclear. Published studies have relied on restimulating circulating CD161⁺ T cells in vitro for quantitation of IL-17-producing cells. While CD161 marks all IL-17⁺ T cells, it is also expressed by other Th subsets. The aim of this study was to directly analyse retinoic acid receptor-related orphan nuclear receptor (ROR)-γ expressing and non-expressing subsets of CD161⁺ T cells to determine the relevance of the Th17 pathway in pSS.

METHODS

We quantitated the frequencies of both CD161^- and RORγ-expressing T cells by comparative flow cytometry in peripheral blood mononuclear cells from a well-stratified cohort of pSS patients and control subjects. We also analysed the expression of antigen D-related HLA (HLA-DR) and CD161 in labial salivary glands from nine subjects undergoing a diagnostic biopsy.

RESULTS

While the frequencies of both RORγ⁺ and RORγ^- subsets of CD161⁺ CD4⁺ T cells were increased in peripheral blood from pSS patients, the increase in the RORγ⁺ subset positively correlated with humoral manifestations of the disease (anti-SSA/SSB autoantibodies and hypergammaglobulinaemia), but not with disease activity, and vice versa for the RORγ^- subset. An increased frequency of HLA-DR⁺ CD161⁺CD4⁺ T cells was observed in labial salivary gland biopsies from pSS patients, suggesting chronic activation of CD161⁺CD4⁺ T cells in the target tissue of the disease.

CONCLUSION

In addition to pointing to CD161 as a marker of a pathogenic subset of CD4⁺ T cells in pSS patients, our data indicate that even though the RORγ⁺ (Th17) CD161⁺ subset might contribute to humoral manifestations of the disease, the RORγ^- (non-Th17) CD161⁺ subset is the one associated with disease activity in pSS patients.