New T-cell epitope of Ro/SS-A 52 kDa protein in labial salivary glands from patients with Sjögren's syndrome

Systemic and Local Interleukin-17 and Linked Cytokines Associated with Sjögren’s Syndrome Immunopathogenesis

Sjogren's syndrome (SS) is an autoimmune disease characterized by lymphocytic infiltration into lacrimal and salivary glands leading to symptomatic dry eyes and mouth. Immunohistological studies have clarified that the majority of infiltrating lymphocytes around the lacrimal glands and labial salivary glands are CD4 positive alphabeta T cells. To analyze the pathogenesis of T cells infiltrating into lacrimal and labial salivary glands, we examined T cell clonotype of these cells in both glands from four SS patients using PCR-single-strand conformation polymorphism (SSCP) and a sequencing method. SSCP analysis showed that some infiltrating T cells in both glands expand clonally, suggesting that the cells proliferate by antigen-driven stimulation. Intriguingly, six to sixteen identical T cell receptor (TCR) Vbeta genes were commonly found in lacrimal glands and labial salivary glands from individual patients. This indicates that some T cells infiltrating into both glands recognize the shared epitopes on autoantigens. Moreover, highly conserved amino acid sequence motifs were found in the TCR CDR3 region bearing the same TCR Vbeta family gene from four SS patients, supporting the notion that the shared epitopes on antigens are limited. In conclusion, these findings suggest that some autoreactive T cells infiltrating into the lips and eyes recognized restricted epitopes of a common autoantigen in patients with SS.

Lacrimal Gland in Sjögren's Syndrome

Salivary Gland Involvement in Chronic Graft-Versus-Host Disease: Prevalence, Clinical Significance, and Recommendations for Evaluation

(2000). T cells and autoantigens in Sjogren's syndrome. Modern Rheumatology: Vol. 10, No. 4, pp. 193-198.

Sjögren syndrome (SS) is characterized by dysfunction of the exocrine glands, particularly the salivary and lacrimal glands. Thus, labial salivary gland biopsy is useful method for diagnosing SS. The aim of the present study was to investigate the microRNA (miRNA or miR) profile of labial salivary glands obtained from SS patients and to examine the correlation of miR-181a and -16 levels with the pathological grade in SS. miRNA expression in labial salivary gland tissues was profiled in 3 female patients with primary SS and 3 female patients with non-SS sicca syndrome using microarray analysis. In addition, a literature search and miRNA target gene prediction were performed to collect miRNAs involved in SS pathogenesis. Subsequent to integrating all database results, miR-181a and -16 were identified to be associated with the Ro/SS-associated antigen A and La/SS-associated antigen B during SS pathogenesis. Therefore, these miRNAs were selected for further verification in labial salivary gland tissues of 28 patients with SS and 18 non-SS sicca syndrome control individuals by quantitative reverse transcription-quantitative polymerase chain reaction. Compared with the control group, 76 miRNAs were upregulated and 51 were downregulated in the labial salivary gland of SS patients according to microarray results. In particular, miR-181a and -16 expression levels in the labial salivary gland of SS patients were decreased in comparison with those in the controls. Furthermore, the decreased expression levels of these miRNAs were associated with the labial salivary pathological focus scores. In conclusion, the present study examined the miRNA profiles in the labial salivary glands of SS patients and detected decreased miR-181a and -16 expression levels compared with the control individuals. Finally, the decreased levels of miR-181a and -16 were associated with the salivary gland pathological focus scores, suggesting that miR-181a and -16 may serve a role in the pathogenesis of SS.

Background:Sjögren’s disease (SjD) is a chronic autoimmune disorder characterized by lymphocytic inflammation and dysfunction of the exocrine glands, particularly the salivary and lacrimal glands. Ultrasonography of Major Salivary Glands (SGUS)...

Primary Sjögren's syndrome (SS) is an autoimmune exocrinopathy that affects the structure and function of salivary and lachrymal glands. Labial salivary gland (LSG) acinar cells from SS patients lose cellular homeostasis and experience endoplasmic reticulum and oxidative stress. The integrated cellular stress response (ISR) is an adaptive pathway essential for restoring homeostasis against various stress-inducing factors, including pro-inflammatory cytokines, and endoplasmic reticulum and oxidative stress. ISR activation leads eIF2α phosphorylation, which transiently blocks protein synthesis while allowing the ATF4 expression, which induces a gene expression program that seeks to optimize cellular recovery. PKR, HRI, GCN2, and PERK are the four sentinel stress kinases that control eIF2α phosphorylation. Dysregulation and chronic activation of ISR signaling have pathologic consequences associated with inflammation. Here, we analyzed the activation of the ISR in LSGs of SS-patients and non-SS sicca controls, determining the mRNA, protein, and phosphorylated-protein levels of key ISR components, as well as the expression of some of ATF4 targets. Moreover, we performed a qualitative characterization of the distribution of ISR components in LSGs from both groups and evaluated if their levels correlate with clinical parameters. We observed that the four ISR sensors are expressed in LSGs of both groups. However, only PKR and PERK showed increased expression and/or activation in LSGs from SS-patients. eIF2α and p-eIF2α protein levels significantly increased in SS-patients; meanwhile components of the PP1c complex responsible for eIF2α dephosphorylation decreased. ATF4 mRNA levels were decreased in LSGs from SS-patients along with hypermethylation of the ATF4 promoter. Despite low mRNA levels, SS-patients showed increased levels of ATF4 protein and ATF4-target genes involved in the antioxidant response. The acinar cells of SS-patients showed increased staining intensity for PKR, p-PKR, p-PERK, p-eIF2α, ATF4, xCT, CHOP, and NRF2. Autoantibodies, focus score, and ESSDAI were correlated with p-PERK/PERK ratio and ATF4 protein levels. In summary, the results showed an increased ISR activation in LSGs of SS-patients. The increased protein levels of ATF4 and ATF4-target genes involved in the redox homeostasis could be part of a rescue response against the various stressful conditions to which the LSGs of SS-patients are subjected and promote cell survival.

Muscarinic acetylcholine receptor autoantibodies in patients with Sjögren’s syndrome

Background:MicroRNAs (miRNAs) are small non-coding RNAs involved in the regulation of gene expression at the post-transcriptional level (by translational blocking or mRNA degradation). The canonical pathway of miRNA biogenesis involves...

Sjögren’s Disease (SjD) is a chronic autoimmune disorder that affects the salivary and lacrimal glands, leading to xerostomia and xerophthalmia. Ultrasonography of Major Salivary Glands (SGUS) is a well-established tool for the identification of the salivary glands’ abnormalities in SjD. Recently, a growing interest has arisen in the assessment of the other exocrine glands with ultrasonography: lacrimal glands (LGUS) and labial salivary glands (LSGUS). The objective of this study is to explore the practical applications of ultra-high frequency ultrasound (UHFUS) in the assessment of lacrimal glands and labial salivary glands. Indeed, UHFUS, with its improved spatial resolution compared to conventional ultrasonography, allows for the evaluation of microscopic structures and has been successfully applied in various medical fields. In lacrimal glands, conventional high-frequency ultrasound (HFUS) can detect characteristic inflammatory changes, atrophic alterations, blood flow patterns, and neoplastic lesions associated with SjD. However, sometimes it is challenging to identify lacrimal glands characteristics, thus making UHFUS a promising tool. Regarding labial salivary glands, limited research is available with conventional HFUS, but UHFUS proves to be a good tool to evaluate glandular inhomogeneity and to guide labial salivary glands biopsy. The comprehensive understanding of organ involvement facilitated by UHFUS may significantly improve the management of SjD patients.

Salivary glands of patients with Sjögren's syndrome (SS) have been shown to be a site of anti-SS-B/La antibody production. The present study investigated differences in the localization of the SS-B/La antigen in labial salivary gland (LSG) tissue between SS and non-SS patients, which may explain the local antigen-driven anti-SS-B/La response. Distribution of SS-B/La was studied immunohistologically in the LSG biopsy samples of 9 SS patients, 10 non-SS patients, and in normal tissues obtained at autopsy within 2 hours after death, using a mouse monoclonal antibody directed to SS-B/La. In 3 SS and 3 non-SS patients, LSGs were also studied with affinity-purified biotinylated human antibodies directed against SS-B/La. In the non-SS patients, SS-B/La was primarily observed in the nucleoli of acinic cells of the LSGs. Patients with either primary SS or secondary SS showed an accumulation of SS-B/La in the nucleoplasm of acinic cells. In the SS patients, SS-B/La was also detected in the cytoplasm as a diffuse or perinuclear staining. Sometimes, SS-B/La was found along the membrane of acinic cells as well. This aberrant nuclear and cytoplasmic distribution of SS-B/La in SS patients correlated well with abnormalities in the composition of the plasma cell population in the LSGs, but not with a lymphocytic focus score > 1. The accumulation and redistribution of SS-B/La in the LSGs may play an important role in the local antigen-driven anti-SS-B/La response in SS, and can also be used to improve the diagnostic possibilities of the LSG biopsy.

Background: Ultra-high frequency ultrasound (UHFUS) has emerged as a valuable tool for assessing the lacrimal glands (LGs) and labial salivary glands (LSGs) in patients with Sjögren’s disease (SD). However, only a few studies have investigated the diagnostic utility of evaluating these two gland types in combination. This study aimed to determine whether assessing both the number of glands involved and the severity of their involvement, based on the presence of very hypoechoic areas (VHA), could enhance diagnostic accuracy and support phenotypic stratification in patients with suspected SD. Methods: Consecutive patients with suspected SD, undergoing LSG biopsy, were included. LSGs and LGs were examined using 48 MHz and 18 MHz probes, respectively. Glandular inhomogeneity was evaluated using a semiquantitative OMERACT score ranging from 0 to 3 for each gland, and a combined score for the LSGs and LGs was calculated (range 0–6). We specifically investigated the presence of very hypoechoic areas ( either lymphoma pattern and/or multiple very hypoechoic areas pattern (1,2)). Serum from each patient was tested for anti-Ro52, anti-Ro60, and anti-SSB/La abs, evaluating the quantitative titer of the autoantibodies with band densitometry. Results: A total of 71 subjects (10 males, 61 females) were enrolled in the study, of whom 28 fulfilled the ACR 2016 classification criteria for Sjögren’s disease (SD). Cohen’s kappa analysis demonstrated moderate concordance in grayscale assessment between LGs and LSGs (k = 0.600, p < 0.001). Receiver operating characteristic (ROC) curve analysis showed that both LG and LSG UHFUS scores, using an optimal cut-off of 2, could effectively differentiate patients with SD from sicca controls, with area under the curve (AUC) values of 0.836 (95% CI: 0.702–0.970) and 0.899 (95% CI: 0.807–0.991), respectively. The combined score yielded excellent diagnostic accuracy (AUC = 0.909, 95% CI: 0.820–0.997; Fig. 1, A-B). All individuals with UHFUS scores >2 in both LGs and LSGs were diagnosed with SD. Patients exhibiting positive UHFUS findings in both gland types ('double positive') displayed significantly higher levels of tissue inflammation, autoantibody titers, and ESSDAI scores compared to those with abnormalities limited to a single gland type. Conversely, patients with UHFUS scores <2 across all glands had the lowest levels of inflammatory biomarkers and autoantibody titers (Fig. 1, C). An increasing burden of VHAs was associated with elevated histological inflammatory markers, autoantibody titers, immunoglobulin levels, and ESSDAI scores, while C4 and lymphocyte counts decreased accordingly (Fig. 1, D). Conclusions: Evaluating multiple exocrine glands increases diagnostic power. Furthermore, as in joint ultrasound, a higher number and greater severity of exocrine gland abnormalities is associated with increased systemic disease activity and heightened biohumoral responses. References. 1) Lorenzon et al., CER, 2021 2) Fulvio et al., CER 2022.

Sjögren's syndrome salivary gland immunopathology: increased laminin expression precedes lymphocytic infiltration.

The aim of this study was to investigate the initiation and progression of autoimmune damage in the lesions of labial salivary glands (LSGs) from primary Sjögren's syndrome (SS) patients by examining the selective localization of T helper (Th) subsets such as Th1, Th2, Th17 regulatory T cells (Tregs) and follicular T helper cells (Tfh). The expression of cytokines and transcription factors associated with these Th subsets in the LSGs from 54 SS patients and 16 healthy controls was examined using real-time polymerase chain reaction (PCR) and immunostaining. Additionally, infiltrating lymphocytes without germinal centre (GC-) and with GC (GC+) in the LSGs specimens from eight SS patients were extracted selectively by laser capture microdissection (LCM). The mRNA expression of these molecules was compared between the two sample groups of GC- and GC+ by real-time PCR. The mRNA expression of cytokines and transcription factors of all T helper (Th) subsets in the LSGs from the SS patients was increased significantly in comparison with controls. In LSGs from the SS patients, Th2 and Tfh was associated closely with strong lymphocytic infiltration; however, Th1, Th17 and Tregs was not. In the selectively extracted lesions of LSGs, Th1 and Th17-related molecules were detected strongly in the GC-, while Th2 and Tfh-related molecules were detected in the GC+. In contrast, no significant association with strong lymphocytic infiltration was observed in Treg-related molecules. These results indicate that SS has selective localization of Th subsets such as Th1, Th2, Th17 and Tfh in the LSGs, which is associated closely with disease severity and/or status. SS might be initiated by Th1 and Th17 cells, and then progressed by Th2 and Tfh cells via GC formation.