Labial salivary gland biopsy in Sjögren's syndrome. Assessment as a diagnostic criterion in 362 suspected cases

Seronegative patients with primary Sjögren's syndrome and non-pSS sicca test positive for anti-SSA/Ro52 and -Ro60 in saliva

OBJECTIVES

Testing for anti-SSA/Ro antibodies in serum is essential in the diagnostic work-up for primary Sjögren's syndrome (pSS). In this study, we aimed to validate our previous assay for detection of salivary anti-SSA/Ro52, and to develop assays for detection of salivary anti-SSA/Ro60 and for detection of anti-Ro52 and -Ro60 in plasma using the electric field-induced release and measurement (EFIRM) platform.

METHODS

Whole saliva samples from two independent Danish cohorts (DN1 and DN2) including 49 patients with pSS, 73 patients with sicca symptoms, but not fulfilling the classification criteria for pSS (non-pSS sicca), and 51 healthy controls (HC), as well as plasma samples from the DN1 cohort were analyzed using EFIRM to detect anti-SSA/Ro52 and -Ro60.

RESULTS

In the DN1 cohort, 100 % in the pSS group and 16 % in the non-pSS sicca group were serum anti-SSA/Ro positive by ELISA. EFIRM detected anti-SSA (Ro52 and/or -Ro60) in plasma and saliva in 100 % and 96 % patients with pSS, and 16 % and 29 % with non-pSS sicca. In the DN2 cohort, 80 % patients with pSS and 26 % with non-pSS sicca were serum anti-SSA/Ro positive. Salivary anti-SSA discriminated patients with pSS from HC and non-pSS sicca with an AUC range of 0.74-0.96 in the DN1 and DN2 cohorts. EFIRM discriminated pSS from non-pSS sicca with an AUC of 0.98 in plasma.

CONCLUSION

Our findings suggest that salivary anti-SSA/Ro antibodies are potential discriminatory biomarkers for pSS, which may also identify seronegative patients, addressing the unmet clinical need of early detection and stratification of pSS.

What Bedside Skills Could the Modern Rheumatologist Possess? Part II. "Certain Technical Procedures"

ABSTRACT

Rheumatologists have never been reluctant to adopt procedures that might enhance their diagnostic or therapeutic powers. Their propensity to penetrate the joints of the patients they were treating set them apart from the general internist. Since the 1980s, when a chance to look inside the joints they were treating attracted a few rheumatologists, other things that could be done at the bedside emerged with now an array of bedside procedures that could be part of a rheumatologist's skill set. Besides gains in diagnosis and/or therapy, each constitutes a chance to restore the physical contact between physician and patient, riven by factors of the last decade, such as electronic medical records and COVID. With such contact so important to satisfaction of the patient and physician alike, acquisition of proficiency in certain technical procedures described herein offers one path to begin restoring rheumatology to the richly fulfilling practice it once was.

Diagnostic Value of Labial Minor Salivary Gland Biopsy: Histological Findings of a Large Sicca Cohort and Clinical Associations

(1) Background: The aim of this study was to analyze labial minor salivary gland biopsy (MSGB) findings of a large sicca cohort and to examine their associations with Sjogren's syndrome (SS)-associated laboratory markers, phenotypic characteristics and systemic manifestations. Moreover, we sought to explore the ability of MSGB to identify SS patients among subjects with pre-diagnosed fibromyalgia (FM). (2) Methods: Included were all patients of three rheumatology departments having undergone a diagnostic MSGB within 9 years. Next to the examination of histological and immunohistochemical findings, we focused on activity and chronicity parameters of the underlying disease, autoantibodies, presence of systemic and hematologic involvement, as well as chronic pain and SS comorbidities. (3) Results: Among the 678 included patients, 306 (45.1%) had a positive focus score (FS). The remaining patients (n = 372) served as control subjects. There were significant correlations between FS and hypergammaglobulinemia (p < 0.001), ANA and rheumatoid factor positivity (both; p < 0.001), a weak significant correlation with erythrocyte sedimentation rate (rho = 0.235; p < 0.001) and a negative correlation with nicotine use (p = 0.002). Within the primary SS subgroup, FS was associated significantly with glandular enlargement (p = 0.007) and systemic hematologic manifestations (p = 0.002). Next to FS, CD20 cell staining showed an excellent diagnostic performance in the diagnosis of SS by an area under the curve of 0.822 (95%CI 0.780-0.864; p < 0.001). Interestingly, 42.1% of all patients with fibromyalgia (FM) having received an MSGB could be diagnosed with SS. (4) Conclusion: By examining one of the largest cohorts in the literature, we could show that MSGB histological and immunohistochemical findings not only play a key role in the classification and diagnosis of SS but could also provide important information regarding SS phenotype and systemic manifestations. Furthermore, MSGB may help differentiate patients with FM from patients with subclinical SS who suffer primarily from chronic pain.

Prevalence of Sjögren's syndrome in patients with dry mouth in the region of Central Hungary

OBJECTIVE

One-third of the Hungarian population suffers from xerostomia. Since there is no evidence of the actual prevalence of Sjögren's syndrome (SS) in Hungary, this study aimed to evaluate the same.

MATERIALS AND METHODS

Data were collected from the Faculty of Dentistry, Semmelweis University from 2008 to 2015. A diagnosis of SS was established based on the American College of Rheumatology and European League Against Rheumatism criteria.

RESULTS

Of the 1076 patients examined with sicca symptoms, 188 patients had confirmed SS. Primary SS (pSS) was diagnosed in 135 patients and secondary SS (sSS) was confirmed in 53 patients. According to the available statistical records of the public health service of Hungary, there were an average of 16 (0.0014%, 5-26) newly diagnosed SS cases in the entire population and 141 SS patient-practitioner consultations (49-232) per 100,000 inhabitants in the country over the past 10 years (based on the past 10 years: 2011-2020).

CONCLUSION

Results revealed that approximately 1/5th-1/6th of patients with sicca symptoms have SS, among whom 72% and 285 have pSS and sSS, respectively. Global Hungarian records simultaneously revealed that the number of both new diagnoses and doctor-SS patient encounters has significantly decreased (by 50%) yearly over the last decade.

[Salivary gland ultrasound or biopsy? : Comparison of methods based on case examples]

BACKGROUND

Ultrasound examination of the salivary glands (SG) is a quick and noninvasive method to detect and semiquantitatively estimate typical changes in the large SG in Sjögren's syndrome (SS). The differential diagnosis of SS is difficult because several diseases and adverse effects of treatment have a similar clinical picture as SS with sicca syndrome and can even induce alterations in the SG (mimic diseases). Hence, for a long time an SG biopsy was regarded as the diagnostic procedure of choice, especially in SS‑A negative patients, whereas the significance of SD sonography is still controversially discussed.

OBJECTIVE

Comparison of typical and atypical changes for SS in the salivary glands in ultrasound and associated histological sections.

MATERIAL AND METHODS

This article describes six patient cases with antibody positive or negative SS with and without typical SS ultrasound patterns, SS-associated lymphoma, sarcoidosis and IgG4-associated disease. The findings of the sonographic examination of the parotid glands and the associated histology of the SD are explained and put into context.

RESULTS

The SSA antibody positive patients with SS show a typical sonographic pattern with hypoechoic foci, especially if the disease has been present for a long time. This pattern can help support the diagnosis of SS. The ultrasound patterns of the mimic diseases sometimes differ significantly from the typical patterns of pSS. The histological examination of the SG helps to corroborate the diagnosis but low histological focus scores, in particular, require a critical synopsis of the clinical, serological and imaging findings.

CONCLUSION

Both salivary gland ultrasound and the histological examination of SG biopsies are justified in the diagnostics and differential diagnosis of SS and sicca syndrome.

EULAR Sjogren's Syndrome Patient Reported Index (ESSPRI) and Other Patient-Reported Outcomes in the Assessment of Glandular Dysfunction in Primary Sjögren's Syndrome

The EULAR Sjögren's Syndrome Disease Activity Index (ESSDAI), EULAR Sjogren's Syndrome Patient Reported Index (ESSPRI), and other patient-reported outcomes (PROs), such as the visual analog scale (VAS) for symptoms and EULAR sicca score (ESS), are used to assess the disease activity of primary Sjögren's syndrome (pSS). Recently, Clinical ESSDAI (ClinESSDAI) and Clinical Trials ESSDAI (ClinTrialsESSDAI) were developed for objective clinical disease activity indexes. However, the relationship of ClinESSDAI and ClinTrialsESSDAI with PROs as well as that between ESSPRI and other PROs and the objective parameters of glandular function in pSS have not been established. Herein, we investigated the correlation of ESSPRI and other PROs with the objective parameters of glandular function and the relationship of PROs with ClinESSDAI and ClinTrialsESSDAI in 66 patients with pSS. Correlations were calculated with Spearman's correlation coefficient. ClinTrialsESSDAI was correlated with ESSPRI, dryness (ESSPRI-Dryness), fatigue, and pain domains of ESSPRI, VAS for oral dryness (oral-VAS), and patient's global assessment. Although ESSPRI did not correlate with the objective parameters of glandular function, ESSPRI-Dryness, ESS, and oral- and ocular-VAS did. These results suggest that ESSPRI-Dryness, ESS, and VAS for symptoms, but not ESSPRI, reflect the glandular dysfunction and that ClinTrialsESSDAI correlates with PROs for dryness in pSS.

Autoantibodies identify primary Sjögren's syndrome in patients lacking serum IgG specific for Ro/SS-A and La/SS-B

OBJECTIVE

Identify autoantibodies in anti-Ro/SS-A negative primary Sjögren's syndrome (SS).

METHODS

This is a proof-of-concept, case-control study of SS, healthy (HC) and other disease (OD) controls. A discovery dataset of plasma samples (n=30 SS, n=15 HC) was tested on human proteome arrays containing 19 500 proteins. A validation dataset of plasma and stimulated parotid saliva from additional SS cases (n=46 anti-Ro+, n=50 anti-Ro-), HC (n=42) and OD (n=54) was tested on custom arrays containing 74 proteins. For each protein, the mean+3 SD of the HC value defined the positivity threshold. Differences from HC were determined by Fisher's exact test and random forest machine learning using 2/3 of the validation dataset for training and 1/3 for testing. Applicability of the results was explored in an independent rheumatology practice cohort (n=38 Ro+, n=36 Ro-, n=10 HC). Relationships among antigens were explored using Search Tool for the Retrieval of Interacting Genes/Proteins (STRING) interactome analysis.

RESULTS

Ro+ SS parotid saliva contained autoantibodies binding to Ro60, Ro52, La/SS-B and muscarinic receptor 5. SS plasma contained 12 novel autoantibody specificities, 11 of which were detected in both the discovery and validation datasets. Binding to ≥1 of the novel antigens identified 54% of Ro- SS and 37% of Ro+ SS cases, with 100% specificity in both groups. Machine learning identified 30 novel specificities showing receiver operating characteristic area under the curve of 0.79 (95% CI 0.64 to 0.93) for identifying Ro- SS. Sera from Ro- cases of an independent cohort bound 17 of the non-canonical antigens. Antigenic targets in both Ro+ and Ro- SS were part of leukaemia cell, ubiquitin conjugation and antiviral defence pathways.

CONCLUSION

We identified antigenic targets of the autoantibody response in SS that may be useful for identifying up to half of Ro seronegative SS cases.

Diagnostic Utility of Minor Salivary Gland Biopsy for Primary Sjögren Syndrome in Patients With Negative Anti-SSA Antibodies

BACKGROUND

Sjögren syndrome is a systemic autoimmune disease characterized by lacrimal and salivary gland inflammation resulting in dry eyes and mouth. Although it is a common disease, diagnosis can be challenging due to its heterogeneous presentation. A positive minor salivary gland biopsy is mandatory to fulfill the 2016 American College of Rheumatology/European League Against Rheumatism (ACR/EULAR) classification criteria for primary Sjögren syndrome in patients who are seronegative for anti-SSA/Ro antibodies. The objective of our study was to evaluate the validity of minor salivary gland biopsy for patients who are SSA antibody-negative yet are suspected of having primary Sjögren syndrome because of compelling symptoms.

METHODS

We conducted a retrospective chart review of adult patients with a negative anti-SSA antibody test who underwent minor salivary gland biopsy to assess suspected Sjögren syndrome at Henry Ford Rheumatology Clinics between January 2005 and December 2019. Patient characteristics and clinical features are described. Sensitivity, specificity, positive predictive value, and negative predictive value are assessed.

RESULTS

A total of 47 patients were included: 46 (97.9%) females and one (2.1%) male. The mean age was 57.2 ± 13.8 years. There were 14 (29.8%) patients who had a positive minor salivary gland biopsy result and 15 (31.9%) patients who had a final diagnosis of Sjögren syndrome. Minor salivary gland biopsy had 93.3% sensitivity (95% confidence interval (CI): 68%-99.8%), 100% specificity (95% CI: 89.1%-100%), 100% positive predictive value (95% CI: 76.8%-100%), and 97% negative predictive value (95% CI: 84.2%-99.9%).

CONCLUSION

The diagnostic value of minor salivary gland biopsy is high for patients who do not have anti-SSA antibodies yet are suspected of having Sjögren syndrome. The results of the study support the consideration of routine minor salivary gland biopsy for identifying Sjögren syndrome in these patients.

hsa-miR-424-5p and hsa-miR-513c-3p dysregulation mediated by IFN-γ is associated with salivary gland dysfunction in Sjögren's syndrome patients

Salivary secretory dysfunction in SS-patients is associated with altered proteostasis, upregulation of ATF6α and components of the ERAD complex, such as SEL1L, and downregulation of XBP-1s and GRP78. Hsa-miR-424-5p is downregulated and hsa-miR-513c-3p is overexpressed in salivary glands from SS-patients. These miRNAs emerged as candidates that could regulate ATF6/SEL1L and XBP-1s/GRP78 levels, respectively. This study aimed to evaluate the effect of IFN-γ on hsa-miR-424-5p and hsa-miR-513c-3p expression and how these miRNAs regulate their targets. In labial salivary glands (LSG) biopsies from 9 SS-patients and 7 control subjects and IFN-γ-stimulated 3D-acini were analyzed. hsa-miR-424-5p and hsa-miR-513c-3p levels were measured by TaqMan assays and their localization by ISH. mRNA, protein levels, and localization of ATF6, SEL1L, HERP, XBP-1s and GRP78 were determined by qPCR, Western blot, or immunofluorescence. Functional and interaction assays were also performed. In LSGs from SS-patients and IFN-γ-stimulated 3D-acini, hsa-miR-424-5p was downregulated and ATF6α and SEL1L were upregulated. ATF6α and SEL1L were decreased after hsa-miR-424-5p overexpression, while ATF6α, SEL1L and HERP increased after hsa-miR-424-5p silencing. Interaction assays revealed that hsa-miR-424-5p targets ATF6α directly. hsa-miR-513c-3p was upregulated and XBP-1s and GRP78 were downregulated. XBP-1s and GRP78 were decreased after hsa-miR-513c-3p overexpression, while increases in XBP-1s and GRP78 were observed after hsa-miR-513c-3p silencing. Furthermore, we determined that hsa-miR-513c-3p targets XBP-1s directly. Significant correlations were found between both miRNA levels and clinical parameters. In conclusion, IFN-γ-dependent hsa-miR-424-5p and hsa-miR-513c-3p levels affect the expression of important factors involved in cellular proteostasis that control secretory function in LSG from SS-patients.

Parotid gland evaluation of menopausal women with xerostomia using the iterative decomposition of water and fat with echo asymmetry and least-squares estimation (IDEAL-IQ) method of MRI: a pilot study

OBJECTIVES

This study aimed to analyze the quantitative fat fraction (FF) of the parotid gland in menopausal females with xerostomia using the iterative decomposition of water and fat with echo asymmetry and least-squares estimation (IDEAL-IQ) method.

METHODS

A total 138 parotid glands of 69 menopausal females were enrolled in our study and participants were divided into normal group and xerostomia group. The xerostomia group was divided into those with or without Sjögren's syndrome. Participants underwent IDEAL-IQ sequences of MRI and the stimulated salivary flow test (s-SFR). The unpaired t-test was used to compare the FFs between the normal and xerostomia groups and between the subgroups with and without Sjögren's syndrome. The correlation between FF and s-SFR was analyzed by Pearson's correlation.

RESULTS

Excellent intra- and interobserver agreement during the measurement of FFs by IDEAL-IQ method (ICC>0.99, respectively). FF value in the xerostomia group was statistically significantly higher than the value in the normal group (p < 0.05). Within the xerostomia group, the average FF value of females with Sjögren's syndrome was higher than that of females without Sjögren's syndrome. However, the difference was not statistically significant (p > 0.05). Within the xerostomia group, FF value correlated negatively with s-SFR (p < 0.05).

CONCLUSIONS

The FF of the parotid gland was higher in the xerostomia group than in the normal group and FF value and s-SFR showed a negative correlation. Analyses of the FF using IDEAL-IQ in menopausal females can be helpful for the quantitative diagnosis of xerostomia.

Bedside labial salivary gland biopsy (LSGBx: Lip biopsy): An update for rheumatologists

Retrieval of minor salivary glands from a labial submucosal site through a minimally invasive bedside procedure was first described nearly 60 years ago and remains an attractive alternative to more invasive surgical procedures to obtain salivary gland tissue for pathologic examination. Examination of glands for features of Sjögren's has constituted the primary use of this procedure but other systemic disorders can affect minor salivary glands and their diagnoses can be supported by biopsy. Performance of the procedure does not require specialized training in head and neck surgery or dentistry, only simple wound closure skills. Skill in performing the procedure enables the clinician to acquire potentially diagnostic material without the need for referral while offering immediate expert feedback to the patient being biopsied. Material obtained at biopsy can also be the focus of research investigations.

Complications after minor salivary gland biopsy: a retrospective study of 630 patients from two Swedish centres

OBJECTIVES

The aims of the study were to investigate the prevalence of impaired sensation after minor salivary gland biopsy (MSGB) in two Swedish centres [Karolinska University Hospital (KUH) and Skåne University Hospital (SUH)] and to assess its impact on quality of life (QoL) and associated risk factors.

METHOD

A questionnaire including questions regarding the presence of impaired sensation, impact on QoL, and impact on everyday life was sent to patients who had undergone MSGB between 2007 and 2016, and their medical notes were scrutinized.

RESULTS

The study included 630 patients (505 from KUH and 125 from SUH). In KUH the biopsies were performed by rheumatologists and in SUH by dentists or oral and maxillofacial surgeons (OMSs). Long-standing, probably permanent, impaired sensation after MSGB was reported by 21% of patients, and was associated with lower age and absence of anti-SSA antibodies. Patients with long-standing impaired sensation reported the inconvenience (1-10) of impaired sensation as 4.0 (2.0-7.0) [median (interquartile range)], and 32% reported an influence on their QoL, the reported influence (1-10) on everyday life being 3.0 (1.0-5.0). When comparing the outcomes from KUH and SUH, patients from SUH reported a significantly lower frequency of long-standing impaired sensation (14% vs 23%; p = 0.02).

CONCLUSION

A high frequency of long-standing impaired sensation after MSGB was found among patients who had undergone MSGB, although it had a low impact on everyday life. The complication frequency was less pronounced when a dentist or an OMS had performed the biopsy.

The integrated stress response is activated in the salivary glands of Sjögren's syndrome patients

Introduction

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.

Methods

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.

Results

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.

Discussion

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.

Current Salivary Glands Biopsy Techniques: A Comprehensive Review

Biopsy is a surgical procedure performed to collect a portion of tissue or organ for diagnostic studies. The aim of the present manuscript is to describe state-of-the-art major and minor salivary gland biopsy techniques and assess the indications and complications of other salivary gland biopsy techniques. A search was performed using the following MeSH terms: biopsy, fine-needle biopsies, image-guided biopsies, frozen sections, and salivary glands disease. A current overview of major and minor salivary glands biopsy techniques was provided. In the oncological field, a comparison was made between the most widely used biopsy method, ultrasound-guided fine-needle aspiration biopsy (US-FNAB), and an alternative method, ultrasound-guided core needle biopsy (US-guided CNB), highlighting the advantages and disadvantages of each. Finally, intra-operative frozen sections (IOFSs) were presented as an additional intraoperative diagnostic method. Minor salivary gland biopsy (MSGB) is the simplest diagnostic method used by clinicians in the diagnosis of inflammatory and autoimmune diseases. In neoplastic lesions, US-FNAB represents the most performed method; however, due to its low diagnostic accuracy for non-neoplastic specimens, US-guided CNB has been introduced as an alternative method.

Imaging Activated-T-Lymphocytes in the Salivary Glands of Patients with Sjögren's Syndrome by 99mTc-Interleukin-2: Diagnostic and Therapeutic Implications

Background: Sjögren’s syndrome (SS) is a progressive autoimmune disease characterized by local mononuclear cell infiltration of the salivary and lachrymal glands. Labial biopsy demonstrates local infiltration by Th1 cells that produce pro-inflammatory cytokines, such as interleukin-2 (IL2). The aim of this study was to assess the utility of 99mTc-labelled-IL2 (99mTc-IL2) in evaluating in vivo the extent and severity of lympho-mononuclear cell infiltration in the salivary glands of patients with SS. Methods: We investigated 48 patients with primary SS and 27 control subjects using 99mTc-IL2 scintigraphy. Furthermore, in a subgroup of 30 patients, we also performed 99mTc-pertechnetate scintigraphy (99mTcO4−) for evaluation of the salivary gland function. Results: 99mTc-IL2 uptake in the salivary glands of SS patients was higher than in the control subjects (1.30 ± 0.16 vs. 0.83 ± 0.08 for parotids and 1.36 ± 0.15 vs. 1.16 ± 0.07 for submandibular glands; p < 0.0001). The salivary gland uptake of 99mTc-IL2 in patients with a longer history of disease was lower compared with the recently diagnosed patients. A significant direct correlation was found between the uptake of 99mTc-IL2 and histology. Conclusions: 99mTc-IL2 scintigraphy showed that the degree of lymphocytic infiltration of major salivary glands is variable in patients with different disease durations. Patients with a high 99mTc-IL2 uptake could be efficiently treated with immuno-modulatory drugs and the efficacy of treatment could be followed-up by 99mTc-IL2 scintigraphy.

Characteristics of Patients with Primary Sjögren's Syndrome and Non-specific Chronic Sialadenitis: A Subtype in Elderly Patients

Introduction

Non-specific chronic sialadenitis (NSCS) is a common pathology of labial salivary glands (LSGs), and NSCS with positive anti-SSA/SSB antibodies is common in clinical practice. Previous studies have evaluated the associations of high focus score (FS) with clinical manifestations in primary Sjögren’s syndrome (pSS) patients extensively, but the characteristics of pSS with NSCS have seldom been investigated. We here analyzed the characteristics of pSS patients with NSCS.

Methods

Among 425 patients who underwent LSG biopsies, 217 had pSS and 37 non-SS sicca patients had NSCS without other diseases (i.e., sicca controls). We categorized these 217 pSS patients into three groups based on the pathology of LSGs: FS ≥ 1 (n = 104), 0 ≤ FS < 1 (n = 76), and NSCS (n = 37). We then compared the three groups while focusing on the NSCS group. Multivariate logistic regression analysis was performed to identify variables that influenced NSCS.

Results

The mean age of pSS patients with NSCS (58.3 ± 11.0 years) was significantly higher than those with FS ≥ 1 (48.5 ± 14.9 years) and 0 ≤ FS < 1 (45.3 ± 13.7 years), but other clinical characteristics were similar. NSCS had a significant positive correlation with age (OR = 7.282, 95% CI 2.085–25.44 and OR = 13.130, 95% CI 3.368–51.189 for patients aged 45–64 years and > 65 years, respectively). Significantly higher levels of lymphocytic infiltration were found in the pSS NSCS group than in the sicca NSCS controls (48.6 vs. 10.8%, respectively).

Conclusions

The pSS patients with NSCS were older than corresponding non-NSCS pSS individuals, but they had similar clinical features. NSCS is associated with age and seldom occurred below the age of 45 years, regardless of the presence or absence of pSS. NSCS may be a subtype of pSS in elderly patients.

Minor Salivary Gland Biopsy in Diagnosis of Sjögren’s Syndrome

Objective

Previous studies have questioned the safety and efficacy of minor salivary gland biopsy in the diagnosis of Sjögren’s syndrome, citing complications and difficulty of pathologic evaluation. This study aims to determine the rate of biopsy specimen adequacy and the risk of complications after minor salivary gland biopsy.

Study Design

Case series.

Setting

Single tertiary care center.

Methods

We reviewed the records of all patients who underwent minor salivary gland biopsy at our institution from October 1, 2016, to September 1, 2021. Demographics, comorbidities, symptoms, and serologic results were recorded. The primary outcome was adequacy of the tissue sample. Complications of the procedure were recorded. Biopsies with at least one focus of ≥50 lymphocytes per 4-mm2 sample were considered positive.

Results

We identified 110 patients who underwent minor salivary gland biopsy. Ninety-three (85%) were female, and the median age was 49.1 years (range, 18.7-80.5). Seventy-seven procedures (70%) were performed in the office setting, and 33 (30%) were performed in the operating room. Nearly all biopsy samples (n = 108, 98%) were adequate, and 33 (31%) were interpreted as positive. Four patients (4%) experienced temporary lip numbness, which resolved with conservative management. No permanent complications were reported after lip biopsy. Nineteen (58%) patients with positive biopsy results had no Sjögren’s-specific antibodies. Most patients with positive biopsy results (n = 20, 61%) subsequently started immunomodulatory therapy.

Conclusion

Minor salivary gland biopsy can be performed safely and effectively in both the office and the operating room. This procedure provides clinically meaningful information and can be reasonably recommended in patients suspected to have Sjögren’s syndrome.

Salivary gland involvement and oral health in patients with coeliac disease

Coeliac disease (CD) is a chronic immune‐mediated enteropathy triggered by ingestion of gluten. The aim of this study was to investigate if the salivary glands as a component of the mucosal immune system are involved in CD, leading to sialadenitis and salivary gland dysfunction and associated oral manifestations. Twenty patients with CD aged 49.2 (SD 15.5 years) and 20 age‐ and gender‐matched healthy controls underwent an interview regarding general and oral health, serological analysis, a clinical oral examination including bitewing radiographs, Candida smear, assessment of salivary mutans streptococci and lactobacilli levels, unstimulated and chewing‐stimulated whole and parotid saliva flow rates, analysis of secretory IgA, and a labial salivary gland biopsy. Xerostomia, mucosal lesions, dry/cracked lips and focal lymphocytic sialadenitis were more prevalent and extensive in patients with CD than in healthy controls. Moreover, the patients had less gingival inflammation and higher whole saliva flow rates than the healthy controls, but did not differ regarding dental health and levels of cariogenic bacteria and Candida. The major salivary gland function appears unaffected, contributing to maintenance of a balanced microbiota and oral health in CD patients. Xerostomia and labial dryness may be related to minor salivary gland inflammation and subsequent impaired mucosal lubrication.

Digital image analysis of intraepithelial B-lymphocytes to assess lymphoepithelial lesions in salivary glands of Sjögren's syndrome patients

OBJECTIVE

Salivary glands of primary SS (pSS) patients characteristically harbour periductal infiltrates, in which lymphoepithelial lesions (LELs) can develop. LELs are composed of hyperplastic ductal epithelium with infiltrating lymphocytes and may assist in the challenging diagnostic process of pSS. As manual identification of LELs remains difficult, we aimed to identify LELs by using an objective digital image analysis (DIA) algorithm that detects intraepithelial lymphocytes.

METHODS

A virtual triple-staining technique developed for this study was used to count intraepithelial lymphocytes in consecutive slides stained for CD3 (T-lymphocytes), high-molecular-weight cytokeratin (hmwCK) (striated ducts) and CD20 (B-lymphocytes) in labial and parotid gland biopsies in a diagnostic cohort of 109 sicca patients. Patients were classified as having pSS or non-SS according to the ACR-EULAR classification criteria.

RESULTS

T-lymphocytes were detected in almost all analysed ducts of pSS and non-SS sicca patients, whereas intraepithelial B-lymphocytes were present in 59-68% of labial and parotid gland biopsies of pSS patients, against only 2-3% of patients classified as non-SS. Intraepithelial B-lymphocytes were found in almost all striated ducts with hyperplasia (LELs). Remarkably, ∼25% of analysed striated ducts without hyperplasia of pSS patients also contained B-lymphocytes (precursor-LELs). Furthermore, presence of intraepithelial B-lymphocytes was associated with clinical parameters of pSS (i.e. serology).

CONCLUSION

The presence of intraepithelial B-lymphocytes in salivary gland biopsies of sicca patients is a clear indicator of pSS and can be used as an objective alternative to LEL scoring. Therefore, identification of B-lymphocyte-containing ducts should be added to the diagnostic histopathological work-up of patients suspected of pSS.

Small RNA Expression Profiling Reveals hsa-miR-181d-5p Downregulation Associated With TNF-α Overexpression in Sjögren’s Syndrome Patients

MicroRNAs (miRNAs) are small non-coding RNAs (sRNA), that alter gene expression by binding to target messenger RNAs (mRNAs) and repressing translation. Dysregulated miRNA expression has been implicated in the pathogenesis of autoimmune diseases such as Sjögren’s syndrome (SS). The aim of this study was to characterize the global profile of sRNAs in labial salivary glands (LSG) from SS-patients and to validate potential miRNA candidates implicated in glandular inflammation. LSG from 21 SS-patients and 9 sicca controls were analyzed. A global next generation sequencing (NGS)-based sRNA profiling approach was employed to identify direct targets whereby differentially expressed miRNAs were predicted using bioinformatics tools. miRNA levels were validated by TaqMan and target mRNA levels were determined by quantitative real-time PCR. We also performed in vitro assays using recombinant TNF-α. NGS shows that ~30% of sRNAs were miRNAs. In comparison with samples from sicca controls, four miRNAs were found differentially expressed in LSG from SS-patients with low focus score (LFS) and 18 from SS-patients with high focus score (HFS). The miRNA with the most significant changes identified by NGS was hsa-miR-181d-5p and downregulation was confirmed by TaqMan analysis. Levels of TNF-α mRNA, a direct target of hsa-miR-181d-5p, were significantly increased and negatively correlated with hsa-miR-181d-5p presence. Moreover, positive correlations between TNF-α transcript levels, focus score, ESSDAI, and autoantibody levels were also detected. Furthermore, TNF-α stimulation decreased hsa-miR-181d-5p levels in vitro. Downregulation of hsa-miR-181d-5p in LSG from SS-patients could contribute to the glandular pro-inflammatory environment by deregulation of its direct target TNF-α. Further dissection of the pathophysiological mechanisms underlying the hsa-miR-181d-5p-mediated action in inflammatory conditions could be useful to evaluate the benefits of increasing hsa-miR-181d-5p levels for restoration of salivary gland epithelial cell architecture and function.

Association between increased Bcl-2, Fas and FasL levels and inflammation extent in labial salivary glands during primary Sjögren's syndrome

BACKGROUND

Primary Sjögren syndrome (pSS) is a chronic autoimmune disease characterized by epithelial atrophy, mononuclear infiltration in exocrine glands resulting in defective function of these glands. In pSS, atrophy of the epithelium is caused by an increased amount of apoptosis.

OBJECTIVE

The main aim of this study is to investigate the role of the apoptosis-related factors by studying Bcl-2, Fas and FasL expression in relation to the extent of inflammation as well as the effect of therapy on the expression of these mediators.

METHODS

In pSS patients (n=62) documented for their serological and clinical features, Fas, FasL and Bcl-2 plasma levels were assessed using enzyme-linked immunosorbent assays. In the same context, we investigated their expression by immunohistochemistry analysis in the labial salivary glands samples in association with the extent of inflammation.

RESULTS

Interestingly, our results indicated that in pSS patients, the plasmatic Bcl-2, Fas and FasL levels, which appear to be associated with the severity of inflammation and were significantly elevated in comparison to the healthy controls. Moreover, a significant decrease in all these factors was observed in patients after combined corticosteroids-hydroxychloroquine therapy. Importantly, we report a strong positive correlation between Bcl-2 and NO levels. The immunohistochemical staining reveals a strong Bcl-2 expression in infiltrating mononuclear cells and a total absence in the acinar cells. The Bcl-2 level varies according to the severity of the pathology. However, the expression of Fas and FasL was less important and predominantly localized in infiltrating mononuclear cells.

CONCLUSION

Our current study highlights the involvement of Bcl-2, Fas and FasL in pSS glands injury. These factors may act as useful predictor markers of a clinical course in pSS suggesting a novel approach in the pSS patients monitoring.

The accuracy of dry surgical field sublabial biopsy in the diagnosis of sicca syndrome

BACKGROUND

Sublabial gland biopsy is the 'gold standard' in establishing the diagnosis of primary Sjögren's syndrome. Bleeding and nerve damage are complications. Our centre has adopted the use of the chalazion clamp to provide a dry surgical field to address these challenges. This study aimed to assess the accuracy of minor salivary gland harvest rate using this technique.

METHOD

A retrospective review of all minor salivary gland biopsies was carried out in a single tertiary referral centre over a five-year period.

RESULTS

Forty-one biopsy patients were identified, with a mean age of 56.1 years. There was 100 per cent accuracy in harvest rate in our series. Twelve patients (29 per cent) were positive for primary Sjögren's syndrome. No patients had a complication immediately or at one month follow up.

CONCLUSION

Dry surgical field sublabial gland biopsy is a safe and highly effective technique in the diagnosis of primary Sjögren's syndrome. Initial results indicate it may provide a higher harvest rate with fewer complications than traditional non-ischaemic techniques.

Increased salivary syndecan-1 level is associated with salivary gland function and inflammation in patients with Sjögren's syndrome

Objectives: Syndecan-1 (SDC-1), a transmembrane heparin sulphate proteoglycan predominantly expressed on epithelial cells, also exists in a soluble form through ectodomain shedding. SDC-1 expression and shedding may be modulated in the inflammatory milieu of primary Sjögren's syndrome (SS). We investigated SDC-1 expression in minor salivary glands (MSGs) and analysed the association between salivary or plasma levels of SDC-1 and clinical parameters in SS.Method: We measured salivary and plasma SDC-1 levels via an enzyme-linked immunosorbent assay and assessed the salivary flow rates (SFRs) in 70 patients with SS and 35 healthy subjects. Disease activity indices, serological markers, salivary gland scintigraphy, and MSG biopsy were evaluated in patients with SS.Results: SDC-1 expression was upregulated on ductal epithelial cells in inflamed salivary glands. Salivary SDC-1 levels in patients significantly exceeded those in healthy subjects [median (interquartile range) 49.0 (20.7-79.1) vs 3.7 (1.7-6.3) ng/mL, p < 0.001] and inversely correlated with SFRs (r = -0.358, p = 0.032) and ejection fractions of the parotid (r = -0.363, p = 0.027) and submandibular (r = -0.485, p = 0.002) glands in salivary gland scintigraphy. Plasma SDC-1 levels were significantly correlated with the EULAR Sjögren's Syndrome Disease Activity Index (r = 0.507, p < 0.001) and EULAR Sjögren's Syndrome Patient Reported Index (r = 0.267, p = 0.033). Focus scores were correlated with salivary SDC-1 levels (r = 0.551, p = 0.004).Conclusion: Salivary and plasma SDC-1 levels may constitute potential biomarkers for salivary gland function and disease activity, respectively, in SS.

Tofacitinib counteracts IL-6 overexpression induced by deficient autophagy: implications in Sjögren's syndrome

OBJECTIVE

Altered homeostasis of salivary gland (SG) epithelial cells in Sjögren's syndrome (SS) could be the initiating factor that leads to inflammation, secretory dysfunction and autoimmunity. Autophagy is an important homeostatic mechanism, whose deficiency is associated with inflammation and accumulation of Janus kinase (JAK)-signal transducer and activator of transcription (STAT) components. We aimed to evaluate whether autophagy is altered in labial SG (LSG) epithelial cells from primary SS (pSS) patients and whether this contributes to inflammation through the JAK-STAT pathway. Furthermore, we investigated the anti-inflammatory effect of the JAK inhibitor tofacitinib in autophagy-deficient (ATG5 knockdown) three-dimensional (3D)-acini.

METHODS

We analysed LSG biopsies from 12 pSS patients with low focus score and 10 controls. ATG5-deficient 3D-acini were generated and incubated with IL-6 in the presence or absence of tofacitinib. Autophagy markers, pro-inflammatory cytokine expression, and JAK-STAT pathway activation were evaluated by PCR or western blot, along with correlation analyses between the evaluated markers and clinical parameters.

RESULTS

LSG from pSS patients showed increased p62 and decreased ATG5 expression, correlating negatively with increased activation of JAK-STAT pathway components (pSTAT1 and pSTAT3). Increased expression of STAT1 and IL-6 correlated with EULAR Sjögren's syndrome disease activity index and the presence of anti-Ro antibodies. ATG5-deficient 3D-acini reproduced the findings observed in LSG from pSS patients, showing increased expression of pro-inflammatory markers such as IL-6, which was reversed by tofacitinib.

CONCLUSION

Decreased expression of ATG5 in LSG epithelial cells from pSS patients possibly contributes to increased inflammation associated with JAK-STAT pathway activation, as evidenced in ATG5-deficient 3D-acini. Interestingly, these results suggest that tofacitinib could be used as an anti-inflammatory agent in pSS patients.

Type I Interferon Dependent hsa-miR-145-5p Downregulation Modulates MUC1 and TLR4 Overexpression in Salivary Glands From Sjögren's Syndrome Patients

Sjögren’s syndrome (SS) is an autoimmune disease that mainly affects salivary glands (SG) and is characterized by overactivation of the type I interferon (IFN) pathway. Type I IFNs can decrease the levels of hsa-miR-145-5p, a miRNA with anti-inflammatory roles that is downregulated in SG from SS-patients. Two relevant targets of hsa-miR-145-5p, mucin 1 (MUC1) and toll-like receptor 4 (TLR4) are overexpressed in SS-patients and contribute to SG inflammation and dysfunction. This study aimed to evaluate if hsa-miR-145-5p modulates MUC1 and TLR4 overexpression in SG from SS-patients in a type I IFN dependent manner. Labial SG (LSG) biopsies from 9 SS-patients and 6 controls were analyzed. We determined hsa-miR-145-5p levels by TaqMan assays and the mRNA levels of MUC1, TLR4, IFN-α, IFN-β, and IFN-stimulated genes (MX1, IFIT1, IFI44, and IFI44L) by real time-PCR. We also performed in vitro assays using type I IFNs and chemically synthesized hsa-miR-145-5p mimics and inhibitors. We validated the decreased hsa-miR-145-5p levels in LSG from SS-patients, which inversely correlated with the type I IFN score, mRNA levels of IFN-β, MUC1, TLR4, and clinical parameters of SS-patients (Ro/La autoantibodies and focus score). IFN-α or IFN-β stimulation downregulated hsa-miR-145-5p and increased MUC1 and TLR4 mRNA levels. Hsa-miR-145-5p overexpression decreased MUC1 and TLR4 mRNA levels, while transfection with a hsa-miR-145-5p inhibitor increased mRNA levels. Our findings show that type I IFNs decrease hsa-miR-145-5p expression leading to upregulation of MUC1 and TLR4. Together, this suggests that type I interferon-dependent hsa-miR-145-5p downregulation contributes to the perpetuation of inflammation in LSG from SS-patients.

A biomarker for lymphoma development in Sjogren's syndrome: Salivary gland focus score

The aim of this study is to explore the role of labial minor salivary gland (LMSG) focus score (FS) in stratifying Sjögren's Syndrome (SS) patients, lymphoma development prediction and to facilitate early lymphoma diagnosis. Ιn an integrated cohort of 1997 patients, 618 patients with FS ≥ 1 and at least one-year elapsing time interval from SS diagnosis to lymphoma diagnosis or last follow up were identified. Clinical, laboratory and serological features were recorded. A data driven logistic regression model was applied to identify independent lymphoma associated risk factors. Furthermore, a FS threshold maximizing the difference of time interval from SS until lymphoma diagnosis between high and low FS lymphoma subgroups was investigated, to develop a follow up strategy for early lymphoma diagnosis. Of the 618 patients, 560 were non-lymphoma SS patients while the other 58 had SS and lymphoma. FS, cryoglobulinemia and salivary gland enlargement (SGE) were proven to be independent lymphoma associated risk factors. Lymphoma patients with FS ≥ 4 had a statistically significant shorter time interval from SS to lymphoma diagnosis, compared to those with FS < 4 (4 vs 9 years, respectively, p = 0,008). SS patients with FS ≥ 4 had more frequently B cell originated manifestations and lymphoma, while in patients with FS < 4, autoimmune thyroiditis was more prevalent. In the latter group SGE was the only lymphoma independent risk factor. A second LMSG biopsy is patients with a FS ≥ 4, 4 years after SS diagnosis and in those with FS < 4 and a history of SGE, at 9-years, may contribute to an early lymphoma diagnosis. Based on our results we conclude that LMSG FS, evaluated at the time of SS diagnosis, is an independent lymphoma associated risk factor and may serve as a predictive biomarker for the early diagnosis of SS-associated lymphomas.

Ultrasound and Bioptic Investigation of Patients with Primary Sjögren's Syndrome

Primary Sjögren's syndrome (pSS) is a chronic and heterogeneous disorder characterized by a wide spectrum of glandular and extra-glandular features. The hallmark of pSS is considered to be the immune-mediated involvement of the exocrine glands and B-cell hyperactivation. This leads pSS patients to an increased risk of developing lymphoproliferative diseases, and persistent (>2 months) major salivary gland enlargement is a well-known clinical sign of possible involvement by B cell lymphoma. Better stratification of the patients may improve understanding of the mechanism underlying the risk of lymphoproliferative disorder. Here, we summarize the role of different imaging techniques and a bioptic approach in pSS patients, focusing mainly on the role of salivary gland ultrasonography (SGUS) and a US-guided core needle biopsy (Us-guided CNB) as diagnostic and prognostic tools in pSS patients with persistent parotid swelling.

Gluten-free diet modulates inflammation in salivary glands and pancreatic islets

OBJECTIVES

A lifelong gluten-free (GF) diet ameliorates autoimmune diabetes in non-obese diabetic (NOD) mice and most likely in humans. Besides diabetes, NOD mice develop focal sialadenitis, as seen in Sjögren's syndrome (SS). In humans, type 1 diabetes (T1D) is also linked to SS. Here, we investigated whether a lifelong GF diet influences the immune cell infiltration in the salivary glands and pancreatic islets in NOD mice.

METHODS

NOD mice were fed a lifelong (i.e. 13 weeks) GF or gluten-containing standard (STD) diet. Insulitis and sialadenitis were scored on H&E-stained paraffin-embedded sections of pancreas and submandibular glands. Immune cell specificity and distribution were investigated immunohistochemically.

RESULTS

There were fewer CD68+ and CD4+ cells in submandibular gland areas with focal sialadenitis as well as reduced insulitis and fewer VEGFR2+ cells in pancreatic islets in mice on GF versus STD diet. The degree of sialadenitis was not significantly lower in GF mice, but sialadenitis and insulitis correlated strongly. Lung weight was lower in GF mice.

CONCLUSION

In NOD mice, a lifelong GF diet reduces infiltration of monocytes/macrophages and T cells in salivary glands and inflammation in pancreatic islets, possibly by reducing VEGFR2, indicating that the linked autoimmune diseases, T1D and SS, may be alleviated by a GF diet.

Value of multilevel sectioning of labial salivary gland biopsies in the diagnosis of Sjögren's syndrome

OBJECTIVES

The objective of this study was to examine the diagnostic value of cutting labial salivary gland (LSG) biopsies at 2 levels in the histological evaluation for Sjögren's syndrome (SS).

STUDY DESIGN

This retrospective study included LSG biopsy specimens from 112 consecutive patients evaluated for SS from 2007 to 2019. Three observers, blinded with regard to patient data, independently scored the degree of focal lymphocytic infiltration (foci) and calculated the focus score in specimens cut at 2 levels 60 µm apart.

RESULTS

Unblinded analysis revealed that the LSG specimens derived from 107 women and 5 men, aged 49.2 ± 22.3 years. Seventy-six patients had SS (70 primary SS and 6 secondary SS) according to the American-European Consensus Group and American College of Rheumatology/European League Against Rheumatism criteria. The average number of LSGs was 5.0 ± 1.4 and the focus scoring area was 16.1 ± 7.6 mm². Compared to baseline, the average number of foci (4.4 vs 5.1, P < .001), focus score (1.7 vs 1.9, P = .01), and cases with focus score >1.0 (61 vs 74%; P = .03) were higher in the second level. Subsequently, an additional 11 cases of SS were confirmed (14%), and 8 non-SS cases were reclassified as SS (22%).

CONCLUSIONS

Histological assessment of an additional section level improves the diagnostic accuracy of the labial salivary gland biopsy to detect histopathological changes consistent with the diagnosis of SS.

Inhibition of JAK-STAT Signaling by Baricitinib Reduces Interferon-γ-Induced CXCL10 Production in Human Salivary Gland Ductal Cells

Sjögren's syndrome (SS) is a chronic autoimmune disease targeting salivary and lacrimal glands. C-X-C motif chemokine ligand 10 (CXCL10) expression is upregulated in lip salivary glands (LSGs) of primary SS (pSS) patients, and CXCL10 involved in SS pathogenesis via immune-cell accumulation. Moreover, interferon (IFN)-γ enhances CXCL10 production via the Janus kinase (JAK)/signal transducer and activator of transcription (STAT) pathway. We investigated the effects of baricitinib, a selective JAK1/2 inhibitor, on both IFN-γ-induced CXCL10 production and immune-cell chemotaxis. We used immunohistochemical staining to determine the expression levels and localization of JAK1 and JAK2 in LSGs of SS patients (n = 12) and healthy controls (n = 3). We then evaluated the effect of baricitinib in an immortalized normal human salivary gland ductal (NS-SV-DC) cell line. Immunohistochemical analysis of LSGs from pSS patients revealed strong JAK1 and JAK2 expression in ductal and acinar cells, respectively. Baricitinib significantly inhibited IFN-γ-induced CXCL10 expression as well as the protein levels in an immortalized human salivary gland ductal-cell clone in a dose-dependent manner. Additionally, western blot analysis showed that baricitinib suppressed the IFN-γ-induced phosphorylation of STAT1 and STAT3, with a stronger effect observed in the case of STAT1. It also inhibited IFN-γ-mediated chemotaxis of Jurkat T cells. These results suggested that baricitinib suppressed IFN-γ-induced CXCL10 expression and attenuated immune-cell chemotaxis by inhibiting JAK/STAT signaling, suggesting its potential as a therapeutic strategy for pSS.

Local complications associated with labial salivary gland biopsy for diagnosis of Sjögren's Syndrome: A retrospective cohort study

Background

To describe local or systemic complications related to the labial salivary glands biopsy (LSGB) used as diagnostic tool for the diagnosis of Sjögren’s Syndrome (SS).

Material and Methods

Clinical databases from a cohort of patients, who underwent LSGB with provisional clinical diagnosis of Sjögren’s Syndrome, were retrospectively reviewed. Pain, assessed by registering the intake of analgesic drugs in the first week following the biopsy, and any further relevant clinical information regarding complications after biopsy were recorded.

Results

50 patients received LSGB. 10 of them (9 women and 1 man) showed histopathological findings compatible with SS. Ten patient (20%) receiving labial biopsy developed local complications: three of them (6%) reported a sensory defect at the surgical site that lasted at most few weeks; three patients (6%) reported pain sensation needing the assumption of analgesic drugs, while one patient (2%) described a transient local burning sensation, which resolved in few days. Three patients (6%) showed cutaneous haematoma in the surgical area and two patients (4%) showed mild mucosal inflammation at the biopsy site.

Conclusions

LSGB is associated with to few and mild complications and it is a useful tool in the diagnosis of SS. The complications usually resolved in few weeks after the biopsy.

Key words:Sjögren’s syndrome, labial salivary glands biopsy, adverse events, diagnosis.

Value of labial salivary gland histopathology for diagnosis of Sjögren's syndrome in patients with anti-centromere antibody positivity

AIM/INTRODUCTION

Although anti-centromere antibody (ACA)+ Sjögren's syndrome (SS) is considered a subtype of SS, it was not included in the recent American College of Rheumatology/ European League Against Rheumatism (ACR/EULAR) SS classification criteria. ACA+ patients without anti-SS-A/Ro antibodies require salivary gland histopathology to fulfill the ACR/EULAR criteria for diagnosis of SS. We reviewed salivary gland histology among ACA+ patients referred for the diagnosis of SS using the ACR/EULAR and Japanese criteria which does not require biopsy.

METHOD

Data from 147 ACA+ patients with dry eyes and/or mouth who visited our department were retrospectively analyzed. Clinical, immunological, and histological data were collected and statistically analyzed.

RESULT

Sixty-five patients (44%) had undergone labial salivary gland biopsy. The frequency of dry mouth was higher in ACA+ patients who had undergone labial salivary gland biopsy than in those who had not (P = .046), while there were no differences in biopsy rates between patients with and without sclerodactyly (P = .51). According to the current ACR/EULAR classification criteria, Greenspan grade of 3 or 4 for labial salivary gland histopathology is required in patients without anti-SS-A/Ro antibody for the diagnosis of SS. Four patients with Greenspan grades <3 and anti-SS-A/Ro antibody met the criteria for SS. In 54 patients in which the ACR/EULAR criteria were met, 53 patients were diagnosed with SS using the Japanese criteria.

CONCLUSION

In ACA+/anti-SS-A/Ro- antibody patients, agreement between ACR/EULAR and Japanese criteria sets was excellent. For easily classifying ACA+ patients as SS cases, salivary gland biopsy should be performed in ACA+ patients with dry symptoms to identify ACA+ patients.

Occlusional Modifications Reversibly Alter Aquaporin 5 Expression and Localization in Rat Salivary Glands

Background

Aquaporin 5 (AQP5) is a water channel–forming protein that plays a key role in saliva secretion. A decrease in masticatory function associated with the molar extraction adversely affects the submandibular salivary gland (SMG) in rats, inducing hypertrophic changes in the acinar cells and the expression of AQP5 in acinar cells or intercalated duct of the SMG. However, changes in AQP5 expression and localization in the SMG in association with occlusal modification have not been fully characterized.

Methods

We examined the influence of the decline and recovery of masticatory function on expression and localization of AQP5 in the rat SMG by inserting and removing an incisor bite plate (IBP). Thirty 5-week-old male Wistar rats were randomly divided into IBP (n = 12), recovery (REC) (n = 6), and control (CON) (n = 12) groups. Each rat in both the IBP and REC groups was fitted with the IBP on its maxillary incisors. Rats without the IBPs served as controls. All rats were fed powder diet and water ad libitum. Rats in the IBP and CON groups were sacrificed after 14 (n = 6) and 28 (n = 6) days after the IBP attachment. In the REC group, the IBP was detached on the 14th day and sacrificed on 28th day after the IBP attachment. AQP5 mRNA expression was quantified by reverse transcription–polymerase chain reaction. Changes in the localization of AQP5 were tracked by immunohistochemical staining.

Results

Attachment of IBP resulted in a decrease in the expression of AQP5 in the IBP group. Changes in the localization of AQP5 were observed between 14 and 28 days in the IBP group. In contrast, changes in the expression and localization of AQP5 were not observed in the REC group.

Conclusion

Findings suggested that a loss of molar occlusion, due to the IBP attachment, altered AQP5 expression and localization in the rat SMG. However, removal of the bite plate allowed the recovery of both AQP5 expression and its normal localization in the SMGs.

Proteomics of saliva, plasma, and salivary gland tissue in Sjögren's syndrome and non-Sjögren patients identify novel biomarker candidates

OBJECTIVE

The aim of this study was to characterize and compare the proteome in whole saliva, plasma, and salivary gland tissue in patients with primary Sjögren's syndrome (pSS) and patients having symptoms of pSS, but not fulfilling the classification criteria, and to search for diagnostic biomarker candidates for pSS.

METHODS

Liquid chromatography tandem mass spectrometry was conducted on whole saliva, plasma, and labial salivary gland tissue samples from 24 patients with pSS and 16 non-Sjögren control subjects (non-pSS). Gene Ontology (GO)-terms and Kyoto Encyclopedia of Genes and Genomes (KEGG)-pathways were applied for functional annotation.

RESULTS

1013 proteins were identified in whole saliva, 219 in plasma, and 3166 in salivary gland tissue. In saliva, 40 proteins differed significantly between the two groups. In pSS, proteins involved in immunoinflammatory processes were upregulated, whereas proteins related to salivary secretion were downregulated. The combination of neutrophil elastase, calreticulin, and tripartite motif-containing protein 29 yielded a receiver-operating characteristic (ROC) value of 0.97 (CI 0.93-1.00). Protein expression in plasma and salivary gland tissue did not differ between the patient groups.

CONCLUSION

The salivary proteome of patients with pSS differed from that of non-pSS patients, indicating that saliva proteomics represents a promising non-invasive diagnostic tool for pSS.

SIGNIFICANCE

Primary Sjögren's syndrome (pSS) is a chronic systemic autoimmune disease, which clinically may present with a wide variety of symptoms and signs. Symptoms of dry eyes and dry mouth due to lacrimal and salivary gland dysfunction are prominent, but not pathognomonic, and an extensive diagnostic work-up including blood tests and labial salivary gland biopsy is often required to distinguish pSS from non-pSS. In this study, we used high throughput proteomics and identified a non-invasive biomarker candidate comprising a combination of three different upregulated salivary proteins, which enables differentiation between patients with pSS and non-pSS patients with an accuracy of 97%. In the future, this could contribute to earlier, more accurate and less costly diagnosis of pSS.

MMP-9 Inhibition Suppresses Interferon-γ-Induced CXCL10 Production in Human Salivary Gland Ductal Cells

Gene expression profiling of lip salivary gland (LSG) has shown that C-X-C motif chemokine 10 (CXCL10) and matrix metalloproteinase 9 (MMP9) expression is upregulated in primary Sjögren's syndrome (pSS) patients. Although CXCL10 and MMP-9 are both associated with pSS pathogenesis, the potential relationship between these two factors has not been investigated. In this study, we used LSG sections from pSS patients and human salivary gland cell lines to investigate the relationship between CXCL10 and MMP-9. Immunofluorescence analyses revealed that CXCL10 and MMP-9 were co-expressed in the LSG of pSS patients, particularly in expanded ductal cells. Furthermore, RT-qPCR analyses on human salivary gland ductal NS-SV-DC cells confirmed that CXCL10 expression was induced by interferon (IFN)-γ, whereas that of MMP9 was stimulated by IFN-α, tumor necrosis factor-α, and interleukin-1β. Remarkably, MMP-9 inhibition in IFN-γ-stimulated NS-SV-DC cells significantly decreased CXCL10 mRNA and secreted protein levels. Further analyses established that MMP-9 inhibition in IFN-γ-stimulated NS-SV-DC cells decreased STAT1 phosphorylation and hence suppressed IFN-γ signaling. Collectively, these results suggest that in addition to its reported role in the destruction of acinar structures, MMP-9 is involved in the IFN-γ-induced production of CXCL10 in pSS lesions. We believe that our findings open the door to the development of novel treatments for pSS, based on the modulation of MMP-9 activity.

Sjögren Syndrome without Focal Lymphocytic Infiltration of the Salivary Glands

OBJECTIVE

Primary Sjögren syndrome (SS) is characterized by a focal lymphocytic infiltrate in exocrine glands. We describe patients who lacked this key feature.

METHODS

We evaluated patients with sicca in a comprehensive clinic at which medical, dental, and ophthalmological examinations were performed. All subjects underwent a minor salivary gland biopsy with focus score calculation. Extraglandular manifestations were also determined. We categorized subjects as high, intermediate, or low in terms of expression of interferon (IFN)-regulated genes.

RESULTS

About 20% (51 of 229, 22%) of those classified as having primary SS had a focus score of zero. Compared to those with anti-Ro positivity and a focus score > 1.0, the patients with focus score of zero (who by classification criteria must be anti-Ro-positive) were statistically less likely to have anti-La (or SSB) and elevated immunoglobulin, as well as less severe corneal staining. The focus score zero patients were less likely to have elevated expression of IFN-regulated genes in peripheral blood mononuclear cells than anti-Ro-positive SS patients with a focal salivary infiltrate.

CONCLUSION

There are only a few clinical differences between patients with primary SS with focus score zero and those with both anti-Ro and a focus score > 1.0. The small subset of focus score zero patients tested did not have elevated expression of IFN-regulated genes, but did have systemic disease. Thus, extraglandular manifestations are perhaps more related to the presence of anti-Ro than increased IFN. This may have relevance to pathogenesis of SS.

Toward better outcomes in Sjögren's syndrome: The promise of a stratified medicine approach

Sjögren's syndrome is a systemic autoimmune disease defined by its targeted inflammation of the salivary and lacrimal glands, resulting in dry mouth and eyes in the majority and persistent or recurrent salivary gland enlargement in a minority of those affected. Involvement of major organs, an increased risk of lymphoma, and autoantibodies against ubiquitous cellular ribonucleoproteins define some of its systemic features. Those affected have a high symptom burden and the development of disease-modifying therapies is thus an urgent need. A stratified medicine approach offers promise as a means of targeting specific therapies to patients for whom the mechanism of action is most relevant. Implementation of this approach will require an understanding of the pathophysiological processes underlying different patient subsets, and then identifying or developing a drug that targets this pathway. Such therapies would be most effective if implemented early in the disease course before the advent of adverse outcomes or glandular damage. This review will provide a disease overview followed by an analysis of the feasibility of a stratified medicine approach, focusing on the disease heterogeneity, predictors of disease progression and adverse outcomes, and recent advances in the development of relevant outcome measures and new therapies.

Minor salivary glands: Clinical, histological and immunohistochemical features of common and less common pathologies

Hundreds of minor salivary glands (MiSGs) are scattered in the oral cavity located at the submucosa layer. Beside their role in the oral cavity lubrication and immunity defence system, MiSGs are beneficial tissue source for diagnosing oral and non-oral related diseases. The advantage of MiSGs as a diagnostic tool reside on their fairly simple excisional procedure on one hand and negligible impact of the normal secretion capability of the salivary gland system on the other hand. The review focuses on pathologies related to developmental, reactive, metabolic, inflammatory and immunologic conditions, Iatrogenic causes and other undefined causes.

Primary Sjögren's syndrome and the eye

Primary Sjögren syndrome is an autoimmune disease that mainly affects exocrine glands such as the salivary and lacrimal glands. In addition, systemic involvement is common. Primary Sjögren syndrome is of particular interest to ophthalmologists as it constitutes an important differential diagnosis in conditions with dry eye disease. In addition, ocular tests for more precisely diagnosing and monitoring primary Sjögren syndrome have become increasingly important, and new therapeutics for local and systemic treatment evolve as a result of increased understanding of immunological mechanisms and molecular pathways in the pathogenesis of primary Sjögren syndrome. We provide an update of interest to ophthalmologists regarding pathogenesis, diagnosis, investigative procedures, and treatment options.

Aberrant MUC1 accumulation in salivary glands of Sjögren’s syndrome patients is reversed by TUDCA in vitro

Objectives

Xerostomia in SS patients has been associated with low quality and quantity of salivary mucins, which are fundamental for the hydration and protection of the oral mucosa. The aim of this study was to evaluate if cytokines induce aberrant mucin expression and whether tauroursodeoxycholic acid (TUDCA) is able to counteract such an anomaly.

Methods

Labial salivary glands from 16 SS patients and 15 control subjects, as well as 3D acini or human submandibular gland cells stimulated with TNF-α or IFN-γ and co-incubated with TUDCA, were analysed. mRNA and protein levels of Mucin 1 (MUC1) and MUC7 were determined by RT-qPCR and western blot, respectively. Co-immunoprecipitation and immunofluorescence assays for mucins and GRP78 [an endoplasmic reticulum (ER)-resident protein] were also performed. mRNA levels of RelA/p65 (nuclear factor-κB subunit), TNF-α, IL-1β, IL-6, SEL1L and EDEM1 were determined by RT-qPCR, and RelA/p65 localization was evaluated by immunofluorescence.

Results

MUC1 is overexpressed and accumulated in the ER of labial salivary gland from SS patients, while MUC7 accumulates throughout the cytoplasm of acinar cells; however, MUC1, but not MUC7, co-precipitated with GRP78. TUDCA diminished the overexpression and aberrant accumulation of MUC1 induced by TNF-α and IFN-γ, as well as the nuclear translocation of RelA/p65, together with the expression of inflammatory and ER stress markers in 3D acini.

Conclusion

Chronic inflammation alters the secretory process of MUC1, inducing ER stress and affecting the quality of saliva in SS patients. TUDCA showed anti-inflammatory properties decreasing aberrant MUC1 accumulation. Further studies are necessary to evaluate the potential therapeutic effect of TUDCA in restoring glandular homeostasis in SS patients.

Saliva: An all-rounder of our body

Saliva is a multifaceted bodily fluid that is often taken for granted but is indispensable for oral health and overall well-being in humans. Although mainly comprised of water (99.5%), proteins, ions and enzymes turn saliva into a viscoelastic solution that performs a variety of vital tasks. This review article gives a brief overview of the salivary gland system, as well as the composition, output and functions of saliva. It also addresses the current applications of saliva for diagnostic purposes, the clinical relevance of saliva in oral diseases as well as current treatment options.

Treatment of primary Sjögren's syndrome with hydroxychloroquine: a retrospective, open-label study

Objectives

To determine whether patients with primary Sjögren's syndrome (SS), diagnosed according to San Diego criteria, had improvement in their laboratory or clinical features during treatment with hydroxychloroquine (6–7 mg/kg/day) for at least two years., Methods: The study population included 50 consecutive patients with primary SS who were diagnosed according to San Diego criteria, and in whom hydroxychloroquine was suggested as treatment. This group included 10 patients who were early dropouts (side effects or desire not to take antimalarial drugs) and 40 patients who received drugs for at least two years (range 24-48 months). In a subset of SS patients, values for ESR (westergren) and quantitative immunoglobulins were available for comparison. Improvement with therapy was defined as: (a) ≥20% improvement in variables of tear flow (Schirmer's test I) or corneal integrity (rose Bengal): (b) ≥20% salivary function (flow rate); and (c) improvement in at least two of the following measures: physicians assessment of global disease activity by ≥ 20%, patient assessment of improvement in pain or fatigue by ≥20%, and ESR improved by ≥20mm/ hr.

Results

In a retrospective study of SS patients who completed the trial, a significant improvement was noted in ocular symptoms (pain and dryness) in patients (55 and 57%) and improved corneal integrity (rose Bengal straining) in 53% of patients. The Schirmer's test was improved by ≥ 2 mm/5 minutes in 50% in patients. Improvement was noted in oral symptoms (pain and dryness) in patients (57 and 60%) and salivary flow rate was increased in 82% of patients. In a subset of SS patients evaluated, the ESR improved by ≥20mm/hr in 17/32 patients (53%) and quantitative IgG level by ≥20% in 8/13 patients (61%). Physician global assessment of overall patient status and patient assessment of overall status indicated improvement in over 62% of patients.

Conclusion

In a retrospective study of patients fulfilling San Diego Criteria for SS, we found: (a) sustained improvement of local symptoms (painful eyes, painful mouth) and improvement of systemic manifestations (arthralgias and myalgias) after treatment with hydroxychloroquine 6-7 mg/kg/day over mean three-year follow-up; (b) laboratory analysis showed a significant improvement in their ESR and their quantitative IgG levels; (c) no significant late toxicity was observed in this study cohort. A prospective study of hydroxychloroquine in patients fulfilling San Diego criteria for SS is indicated.

The role of stroma and epithelial cells in primary Sjögren's syndrome

Primary SS (pSS) is a chronic autoimmune condition characterized by infiltration of the exocrine glands and systemic B cell hyperactivation. This glandular infiltration is associated with loss of glandular function, with pSS patients primarily presenting with severe dryness of the eyes and mouth. Within the affected glands, the infiltrating lymphocytes are organized in tertiary lymphoid structures. Tertiary lymphoid structures subvert normal tissue architecture and impact on organ function, by promoting the activation and maintenance of autoreactive lymphocytes. This review summarizes the current knowledge about the role of stromal cells (including endothelium, epithelium, nerves and fibroblasts) in the pathogenesis of pSS, in particular the interactions taking place between stromal cells and infiltrating lymphocytes. We will provide evidences pointing towards the driving role of stromal cells in the orchestration of the local inflammatory milieu, thus highlighting the need for therapies aimed at targeting this compartment alongside classical immunosuppression in pSS.

Distinct Regulation of CXCL10 Production by Cytokines in Human Salivary Gland Ductal and Acinar Cells

CXCL10, a CXC chemokine induced by interferon-gamma [IFN-γ], has been observed in a wide variety of chronic inflammatory disorders and autoimmune conditions. Although CXCL10 is known to be overexpressed in the salivary glands of individuals with primary Sjögren's syndrome (pSS), it is unclear which cells produce CXCL10 under what types of stimulations. Here, we investigated the precise molecular mechanisms by which CXCL10 was produced in human salivary gland ductal (NS-SV-DC) and acinar (NS-SV-AC) cell lines. Our results demonstrated that NS-SV-DC cells produced higher levels of CXCL10 compared to NS-SV-AC cells. In addition, our findings demonstrated that the regulator of the enhancement of CXCL10 was different between NS-SV-DC and NS-SV-AC cells, i.e., interferon-gamma (IFN-γ) had more potential than interferon-alpha (IFN-α), tumor necrosis factor (TNF)-α, and interleukin (IL)1-β in the induction of CXCL10 production in NS-SV-DC cells, whereas TNF-α had potential to induce CXCL10 production in NS-SV-AC cells. A Western blot analysis demonstrated that IFN-γ enhanced the production of CXCL10 via both the JAK/STAT1 pathway and the NF-κB pathway in NS-SV-DC cells, whereas TNF-α enhanced the production of CXCL10 via the NF-κB pathway in NS-SV-AC cells. The results of study suggest that the CXCL10 overexpression in the salivary glands is caused mainly by IFN-γ-stimulated salivary gland ductal cells. The enhanced production of CXCL10 by IFN-γ from ductal cells may result in the inflammation of pSS lesions.

Association of high 5-hydroxymethylcytosine levels with Ten Eleven Translocation 2 overexpression and inflammation in Sjögren's syndrome patients

Here, we determined the 5-hydroxymethylcytosine (5hmC), 5-methylcytosine (5mC), Ten Eleven Translocation (TETs), and DNA methyltransferases (DNMTs) levels in epithelial and inflammatory cells of labial salivary glands (LSG) from Sjögren's syndrome (SS)-patients and the effect of cytokines on HSG cells. LSG from SS-patients, controls and HSG cells incubated with cytokines were analysed. Levels of 5mC, 5hmC, DNMTs, TET2 and MeCP2 were assessed by immunofluorescence. In epithelial cells from SS-patients, an increase in TET2, 5hmC and a decrease in 5mC and MeCP2 were observed, additionally, high levels of 5mC and DNMTs and low levels of 5hmC were detected in inflammatory cells. Cytokines increased TET2 and 5hmC and decreased 5mC levels. Considering that the TET2 gene.promoter contains response elements for transcription factors activated by cytokines, together to in vitro results suggest that changes in DNA hydroxymethylation, resulting from altered levels of TET2 are likely to be relevant in the Sjögren's syndrome etiopathogenesis.

Synaptotagmin-1 overexpression under inflammatory conditions affects secretion in salivary glands from Sjögren's syndrome patients

Sjögren's syndrome (SS) is an autoimmune exocrinopathy associated with severe secretory alterations by disruption of the glandular architecture integrity, which is fundamental for a correct function and localization of the secretory machinery. Syt-1, PI(4,5)P₂ and Ca²⁺ are significant factors controlling exocytosis in different secretory cells, the Ca²⁺ role being the most studied. Salivary acinar cells from SS-patients show a defective agonist-regulated intracellular Ca²⁺ release together with a decreased IP3R expression level, and this condition may explain a reduced water release. However, there are not reports where Syt-1, PI(4,5)P₂ and Ca²⁺ in acinar cells of SS patients had been studied. In the present study, we analyzed the expression and/or localization of Syt-1 and PI(4,5)P₂ in acinar cells of labial salivary gland biopsies from SS-patients and control individuals. Also, we evaluated whether the overexpression of Syt-1 and the loss of cell polarity induced by TNF-α or loss of interaction between acinar cell and basal lamina, alters directionality of the exocytosis process, Ca²⁺ signaling and α-amylase secretion in a 3D-acini model stimulated with cholinergic or β-adrenergic agonists. In addition, the correlation between Syt-1 protein levels and clinical parameters was evaluated. The results showed an increase of Syt-1 mRNA and protein levels, and a high number of co-localization points of Syt-1/STX4 and PI(4,5)P₂/Ezrin in the acinar basolateral region of LSG from SS-patients. With regard to 3D-acini, Syt-1 overexpression increased exocytosis in the apical pole compared to control acini. TNF-α stimulation increased exocytic events in the basal pole, which was further enhanced by Syt-1 overexpression. Additionally, altered acinar cell polarity affected Ca²⁺ signaling and amylase secretion. Overexpression of Syt-1 was associated with salivary gland alterations revealing that the secretory dysfunction in SS-patients is linked to altered expression and/or localization of secretory machinery components together with impaired epithelial cell polarity. These findings provide a novel insight on the pathological mechanism implicated in ectopic secretory products to the extracellular matrix of LSG from SS-patients, which might initiate inflammation.

Cepharanthine Inhibits IFN-γ-Induced CXCL10 by Suppressing the JAK2/STAT1 Signal Pathway in Human Salivary Gland Ductal Cells

Cepharanthine, a biscolaurine alkaloid isolated from the plant Stephania cephalantha Hayata, has been reported to have potent anti-inflammatory properties. Here, we investigated the effects of cepharanthine on the expression of CXCL10 (a CXC chemokine induced by interferon-gamma [IFN-γ] that has been observed in a wide variety of chronic inflammatory disorders and autoimmune conditions) in IFN-γ-treated human salivary gland cell lines. We observed that IFN-γ-induced CXCL10 production in NS-SV-DC cells (a human salivary gland ductal cell line), but not in NS-SV-AC cells (a human salivary gland acinar cell line). Cepharanthine inhibited the IFN-γ-induced CXCL10 production in NS-SV-DC cells. A Western blot analysis showed that cepharanthine prevented the phosphorylation of JAK2 and STAT1, but did not interfere with the NF-κB pathway. Moreover, cepharanthine inhibited the IFN-γ-mediated chemotaxis of Jurkat T cells. These results suggest that cepharanthine suppresses IFN-γ-induced CXCL10 production via the inhibition of the JAK2/STAT1 signaling pathway in human salivary gland ductal cells. Our findings also indicate that cepharanthine could inhibit the chemotaxis of Jurkat T cells by reducing CXCL10 production.

Relationship of MR imaging of submandibular glands to hyposalivation in Sjögren's syndrome

OBJECTIVE

We analysed the correlation between magnetic resonance images of the parotid and submandibular glands and the salivary flow rate in patients with Sjögren's syndrome.

METHODS

We retrospectively reviewed magnetic resonance images (heterogeneous signal-intensity distribution and gland volume on T1- and fat-suppressed T2-weighted images, and multiple high-signal-intensity spots on magnetic resonance sialograms in the parotid and submandibular glands) obtained from 66 patients who were diagnosed with Sjögren's syndrome. We evaluated the relationship between these imaging features and their salivary flow rates in stimulated and unstimulated conditions.

RESULTS

We found that as the disease progressed, both the heterogeneous signal-intensity distribution and the volumes of the parotid and the submandibular glands were significantly related to the stimulated and the unstimulated salivary flow rate. These imaging features were more highly correlated in assessments of the submandibular gland than in those of the parotid gland for both stimulated and unstimulated salivary flow rates.

CONCLUSIONS

Magnetic resonance image features of heterogeneity and smaller volume in the submandibular gland are reliable for predicting hyposalivation related to the progression of Sjögren's syndrome.