Histopathology, salivary flow and ultrasonography of the parotid gland: three complementary measurements in primary Sjögren's syndrome

Clinical value of salivary gland ultrasonography in evaluating secretory function, disease activity, and lymphoma risk factors in primary Sjögren's syndrome

INTRODUCTION/OBJECTIVES

Salivary gland ultrasonography (SGUS) has been investigated for its diagnostic usefulness in replacing invasive minor salivary gland biopsy (MSGB) in primary Sjögren's syndrome (pSS). However, its broader clinical value remains unclear. This study aimed to assess the clinical significance of SGUS in evaluating secretory function, disease activity, and lymphoma risk factors in pSS.

METHOD

One hundred fifty pSS patients who visited Seoul St. Mary's Hospital between January 2019 and July 2023 were included. Parameters related to secretory function, disease activity, and lymphoma risk factors were obtained. Associations between SGUS grades and secretory function or disease activity parameters were determined. Subgroup analyses based on SGUS grade or the presence of lymphadenopathy (LAP) in SGUS were also performed.

RESULTS

SGUS grades correlated significantly with parameters of salivary gland secretory function and disease activity. Higher SGUS grades were associated with higher scores of overall EULAR Sjögren's Syndrome Disease Activity Index (ESSDAI), ESSDAI glandular domain, EULAR Sjögren's Syndrome Patient Reported Index (ESSPRI) dryness domain, and physician or patient global assessment. Patients with the highest SGUS grade (overall score = 6) showed higher prevalence of laboratory risk factors or extraglandular manifestations related to lymphoma development than others. Detection of LAP by SGUS was associated with reduced salivary flow rates and higher ESSDAI, ESSPRI scores, and patient global assessments.

CONCLUSIONS

Our results suggest that SGUS grades and the presence of LAP in SGUS findings are associated with clinical parameters representing secretory function and disease activity in pSS. High SGUS grades are associated with risk factors for lymphoma development. Key Points • SGUS grades showed significant correlations with clinical parameters related to salivary gland function and disease activity in patients with pSS. • pSS patients with the highest SGUS grade exhibited a higher prevalence of laboratory risk factors or extraglandular manifestations potentially related to lymphoma development compared to others. • These associations were more pronounced in the parotid gland than in the submandibular gland. • LAP identified by SGUS showed significant associations with clinical parameters related to the quality of life of patients with pSS.

Imaging of the Major Salivary Glands in Rheumatic Disease

Salivary gland involvement is a common feature of rheumatologic disease. The authors review the anatomy of the major salivary glands and the uses of imaging modalities such as ultrasound, MRI, computed tomography, sialography, and scintigraphy in evaluating the major salivary glands in rheumatologic disease.

Clinical stratification of 1318 Primary Sjögren's Syndrome patients

OBJECTIVE

Primary Sjögren's Syndrome (pSS) is a complex autoimmune disorder characterized by diverse clinical manifestations yet lacking effective therapeutic strategies currently. This study aims to gain a thorough understanding of the clinical landscape of pSS and further delineate its clinical subtypes, thereby enabling the efficient management for pSS.

METHODS

We conducted a cross-sectional observational study of 1318 pSS patients. The pSS patients were categorized and compared based on gender, anti-SSA antibodies, and labial salivary gland biopsies (LGSB). Unsupervised clustering analysis was employed to identify pSS subtypes using systemic involvement among patients. Furthermore, we assessed clinical and biological variances among these subtypes.

RESULTS

Through group comparisons, we observed more pronounced extraglandular manifestations among male patients, SSA-negative group, and those with positive LGSB results. Based on systemic involvement, pSS patients were categorized into four groups. C1 exhibited minimal systemic involvement, lacking hematologic or serologic manifestations, with the lowest ESSDAI scores. C2 presented with serologic changes in all patients, partial joint involvement, and no hematologic systemic manifestations. C3 lacked joint involvement but all members displayed hematologic systemic involvement, with higher rates of renal, cutaneous, and systemic manifestations. C4 encompassed patients with joint and hematologic involvement, displaying the highest ESSDAI scores. The positivity rates of antibodies, immunological parameters, and inflammatory markers exhibited significant differences among the groups. Furthermore, notable variances were observed in the expression of peripheral blood transcriptomic modules among these groups.

CONCLUSION

In this cohort study, we summarized the clinical characteristics of Chinese patients with pSS and identified four distinct subgroups of pSS based on systemic involvement, revealing clinical and molecular disparities that unveil distinct pathobiological endotypes. Our findings hold significant implications for clinical management.

Connecting salivary gland inflammation to specific symptoms in Sjögren's disease

INTRODUCTION

The complex nature of Sjögren's Disease (SjD) necessitates a comprehensive and patient-centered approach in both diagnosis and management. This narrative review emphasizes the need for a holistic understanding of the connection between salivary gland inflammation and oral symptoms in SjD.

AREAS COVERED

The intricate relationship between salivary gland inflammation and dry mouth is explored, highlighting the variability in associations reported in studies. The association of the severity of xerostomia and degree of inflammation is also discussed. The frequent presence of recurrent sialadenitis in SjD further accentuates the connection of compromised salivary gland function and inflammation. The review additionally discusses local inflammatory factors assessed through salivary gland biopsies, which could potentially serve as predictors for lymphoma development in SjD. Insights into compromised quality of life and hypercoagulable state and their association with salivary gland inflammations are provided. Advancements in noninvasive imaging techniques, particularly salivary gland ultrasonography and color Doppler ultrasound, offer promising avenues for noninvasive assessment of inflammation.

EXPERT OPINION

There is a need for longitudinal studies to unravel the connections between salivary gland inflammation and oral symptoms. This will enhance management strategies and optimize treatment outcomes for SjD patients.

Influencing Factors, Reference Range and Repeatability of Salivary Gland Ultrasound Viscoelastic Imaging in Healthy Adults

OBJECTIVE

The study aimed to determine the influencing factors, reference range, the changes of salivary gland secretion function and repeatability of measurements taken from ultrasound (US) viscoelastic imaging in the salivary glands of healthy adults.

METHODS

From August 2023 to October 2023, 206 healthy adults were recruited. In November 2023, 50 healthy adults were recruited for acid stimulation testing. All volunteers underwent conventional and viscoelastic US of the salivary glands. The viscoelasticity values in different regions of interest (ROI), observers, genders, ages, body mass index (BMI) groups and before and after acid stimulation were compared separately. A two-sided 95% reference range was estimated accordingly.

RESULTS

There was no difference in the E-mean and V-mean values among different ROIs (p > 0.05). The intra-group correlation coefficient values between the different observers were all >0.908. Except for the influence of age on the E-mean value of the parotid gland, the V-mean of the parotid gland, the E-mean and V-mean of the submandibular gland were not affected by age, gender or BMI. Finally, differences were detected in the E-means and V-means of the parotid and submandibular glands before and after acid stimulation (p < 0.05).

CONCLUSION

US viscoelastic imaging is a simple and reliable technique for evaluating the stiffness and viscosity of salivary glands in healthy adults. It also can be used to dynamically evaluate the changes of salivary gland secretion function.

More severe parotid gland histopathology in paediatric-onset than in adult-onset Sjögren's disease

OBJECTIVES

The aim of this study was to assess the histopathological features of the parotid glands in patients with paediatric-onset Sjögren's disease (pedSjD) in comparison to patients with adult-onset Sjögren's disease (adSjD).

METHODS

This study was performed in Groningen, the Netherlands. Patients with pedSjD from a diagnostic paediatric cohort (n=19), patients with adSjD from a diagnostic adult cohort (n=32) and patients with adSjD who participated in a clinical trial (n=42) with a baseline parotid gland biopsy were included. Parotid gland biopsies were analysed after (immuno)histological staining for SjD-related histopathological markers and compared between groups.

RESULTS

All characteristic histopathological features of adSjD were also observed in pedSjD. There were no significant differences in lymphoepithelial lesions or immunoglobulin A (IgA)/IgG plasma cell shift between the pedSjD and the adSjD cohorts. However, compared with the diagnostic adSjD cohort (with comparable total EULAR Sjögren's Syndrome Disease Activity Index (ESSDAI) scores), pedSjD showed more severe lymphocytic infiltration as reflected by a higher focus score (p=0.003), a higher relative surface area of CD45+ infiltrate (p=0.041), higher numbers of B and T lymphocytes/mm2 (p=0.004 and p=0.029, respectively), a higher B/T lymphocyte ratio (p=0.013), higher numbers of CD21+ follicular dendritic cell networks/mm2 (p=0.029) and germinal centres (GC)/mm2 (p=0.002). Compared with the trial adSjD cohort, with significant higher total ESSDAI scores (p=0.001), only the B/T lymphocyte ratio and numbers of GC/mm2 were significantly higher in the pedSjD cohort (p=0.023 and p=0.018, respectively).

CONCLUSION

Patients with pedSjD exhibit more pronounced histopathological features compared with patients with adSjD at diagnosis. Notably, the histopathology of patients with pedSjD aligns more closely with that observed in an adSjD clinical trial cohort, with even stronger B lymphocyte involvement.

Case Series of Changes in Greyscale and Power Doppler Signals on Salivary Gland Ultrasonography after Treatment in Patients with Sjögren's Syndrome

The usefulness of greyscale (GS) in salivary gland ultrasonography for Sjögren's syndrome (SS) has been established; however, limited information is currently available on power Doppler signals (PDs), and changes after treatment remain unknown. PDs are considered to represent glandular inflammation, which indicates the worsening of GS in later years. We examined the changes in PDs in three immunosuppressant-treated SS patients. PDs decreased, along with GS and markers of disease activity, after treatment. PDs have the potential to provide insights into glandular inflammation in real time; however, large-scale studies on their clinical usefulness are needed.

Anti-centromere antibody positivity is an independent variable associated with salivary gland ultrasonography score in Sjögren's syndrome

Sjögren's syndrome (SS) is an autoimmune disease characterized by periductal lymphocytic infiltration of the salivary and lacrimal glands. SS also exhibits extra-glandular manifestations and specific autoantibodies. Salivary gland ultrasonography (SGUS) is a common procedure used to assess the severity of glandular involvement. However, the association between SGUS and extra-glandular lesions remains poorly understood. This study aimed to identify clinical indices, including disease activity, associated with glandular involvement using SGUS in patients with SS. We included 115 patients with SS and 90 without SS. Patients with SS had significantly higher ultrasonography (US) score than patients without SS. Multivariate analysis revealed focus score, Saxon test positivity, and anti-centromere antibody (ACA) positivity as independent variables associated with the US score in patients with SS. In addition, these results were similar to those obtained in patients with primary SS. Patients with SS and ACA positivity had higher US score and an increased prevalence of hyperechoic bands in the parotid glands and submandibular glands. In conclusion, this study indicated that ACA positivity is associated with the US score in patients with SS. These results suggest that US findings in patients with ACA positivity might show specific changes in the salivary glands, especially fibrosis.

Diagnostic accuracy of ultrasonography in relation to salivary gland biopsy in Sjögren's syndrome: a systematic review with meta-analysis

OBJECTIVES

To evaluate the accuracy of major salivary gland ultrasonography (SGUS) in relation to minor salivary gland biopsy (mSGB) in the diagnosis of Sjögren's syndrome (SS).

METHODS

A systematic review and meta-analysis were performed. Ten databases were searched to identify studies that compared the accuracy of SGUS and mSGB. The risk of bias was assessed, data were extracted, and univariate and bivariate random-effects meta-analyses were done.

RESULTS

A total of 5000 records were identified; 13 studies were included in the qualitative synthesis and 10 in the quantitative synthesis. The first meta-analysis found a sensitivity of 0.86 (95% CI: 0.74-0.92) and specificity of 0.87 (95% CI: 0.81-0.92) for the predictive value of SGUS scoring in relation to the result of mSGB. In the second meta-analysis, mSGB showed higher sensitivity and specificity than SGUS. Sensitivity was 0.80 (95% CI: 0.74-0.85) for mSGB and 0.71 (95% CI: 0.58-0.81) for SGUS, and specificity was 0.94 (95% CI: 0.87-0.97) for mSGB and 0.89 (95% CI: 0.82-0.94) for SGUS.

CONCLUSIONS

The diagnostic accuracy of SGUS was similar to that of mSGB. SGUS is an effective diagnostic test that shows good sensitivity and high specificity, in addition to being a good tool for prognosis and for avoiding unnecessary biopsies. More studies using similar methodologies are needed to assess the accuracy of SGUS in predicting the result of mSGB. Our results will contribute to decision-making for the implementation of SGUS as a diagnostic tool for SS, considering the advantages of this method.

Targeting plasma cells in systemic autoimmune rheumatic diseases - Promises and pitfalls

Plasma cells are the antibody secretors of the immune system. Continuous antibody secretion over years can provide long-term immune protection but could also be held responsible for long-lasting autoimmunity in case of self-reactive plasma cells. Systemic autoimmune rheumatic diseases (ARD) affect multiple organ systems and are associated with a plethora of different autoantibodies. Two prototypic systemic ARDs are systemic lupus erythematosus (SLE) and Sjögren's disease (SjD). Both diseases are characterized by B-cell hyperactivity and the production of autoantibodies against nuclear antigens. Analogues to other immune cells, different subsets of plasma cells have been described. Plasma cell subsets are often defined dependent on their current state of maturation, that also depend on the precursor B-cell subset from which they derived. But, a universal definition of plasma cell subsets is not available so far. Furthermore, the ability for long-term survival and effector functions may differ, potentially in a disease-specific manner. Characterization of plasma cell subsets and their specificity in individual patients can help to choose a suitable targeting approach for either a broad or more selective plasma cell depletion. Targeting plasma cells in systemic ARDs is currently challenging because of side effects or varying depletion efficacies in the tissue. Recent developments, however, like antigen-specific targeting and CAR-T-cell therapy might open up major benefits for patients beyond current treatment options.

Salivary ultrasonography and histopathologic evaluation of secondary Sjögren's syndrome in rheumatoid arthritis patients

Novel modalities, such as salivary ultrasonography (SGUS) and shear wave elastography (SWE), have previously been introduced to evaluate Sjögren's syndrome (SS). However, in secondary SS (sSS), the diagnostic performance of SGUS and its relationship with clinicopathological characteristics have not yet been clearly defined. In this study, we aimed to investigate sSS in RA patients using SGUS and SWE and sought to determine its pathological correlations. Thirty-one RA patients who presented with sicca symptoms were included to be evaluated on SS, and were compared with 18 primary SS (pSS) patients. All subjects were assessed through SGUS, SWE, and conventional diagnostic approaches for SS, including minor salivary gland biopsy (MSGB). In SGUS evaluation, two separate scoring systems, suggested by Hocevar and OMERACT, were used. Among 31 RA patients with sicca symptoms, 19 (61.2%) were diagnosed as sSS. Similar to pSS, SGUS showed good diagnostic performance (sensitivity 68.4% and 78.9%, and specificity 91.7% and 75.0% for Hocever and OMERACT, respectively) in differentiating sSS from RA patients with simple sicca symptoms. The sSS and pSS patients exhibited significantly higher lymphoid infiltration areas in MSGB than RA patients without SS. Focus score and lymphoid infiltration areas correlated well with sonographic severity. Severity of fibrosis in MSGB showed better positive correlation with SWE than with SGUS. Similar to pSS, SGUS shows good diagnostic performance for sSS in RA patients. SWE reflects histopathologic chronicity of MSGB well in both pSS and sSS.

Why do drug treatments fail in Sjögren's disease? Considerations for treatment, trial design and interpretation of clinical efficacy

INTRODUCTION

Despite ongoing efforts to develop effective therapeutics, no disease-modifying drugs have been officially licensed for the indication of Sjögren's disease (SjD). This is partly due to heterogeneity in disease manifestations, which complicates drug target selection, trial design and interpretation of clinical efficacy in SjD.

AREAS COVERED

Here, we summarize developments and comment on challenges in 1) identifying the right target for treatment, 2) selection of the primary study endpoint for trials and definition of clinically relevant response to treatment, 3) inclusion criteria and patient stratification, 4) distinguishing between disease activity and damage and 5) establishing the effect of treatment considering measurement error, natural variation, and placebo or nocebo responses.

EXPERT OPINION

Targets that are involved in both the immune cell response and dysregulation of glandular epithelial cells (e.g. B-lymphocytes, type-I interferon) are of particular interest to treat both glandular and extra-glandular manifestations of SjD. The recent development of composite study endpoints (CRESS and STAR) may be a crucial step forward in the search for clinically effective systemic treatment of patients with SjD. Important additional areas for future research are symptom-based and/or molecular pathway-based patient stratification, prevention of irreversible damage, and establishing the effect of treatment.

Diagnostic Evaluation Using Salivary Gland Ultrasonography in Primary Sjögren's Syndrome

The purpose of this study is to investigate the clinical manifestations in patients with early primary Sjögren's syndrome (pSS) based on the severity score found by salivary gland ultrasonography. Thirty-five newly diagnosed patients with early pSS were enrolled and divided into mild (score 0-1) and severe (score 2-3) groups according to the salivary gland ultrasonography grade (SGUS) scores at baseline. Clinical evaluation, ESSPRI and ESSDAI index values, sicca symptoms of the mouth, salivary capacity, and serum autoantibodies and cytokines were investigated. The mean age of pSS patients at diagnosis was 49.9 ± 11.9 years, and the mean duration of sicca symptoms was 0.58 years. ESSPRI (EULAR Sjögren's syndrome patient report index) and ESSDAI (EULAR Sjögren's syndrome disease index) scores were 15.97 and 4.77, respectively. Clinical manifestations, including the low production of saliva and autoantibody production, such as antinuclear antibodies, rheumatoid factor, and anti-SSA antibody, were found. A higher prevalence of rheumatoid factor (p = 0.0365) and antinuclear antibody (p = 0.0063) and a higher elevation of total IgG (p = 0.0365) were found in the severe group than in the mild group. In addition, the elevated titer of IL-25 was detected in the severe group than in the mild group. This observation indicated that salivary gland ultrasonography grade (SGUS) scans may help physicians diagnose pSS and the elevated titer of IL-25 in patients may be implicated in the pathogenesis of pSS.

Diagnostic value of ultrasound evaluation of major salivary glands for Sjögren's syndrome based on the novel OMERACT scoring system

OBJECTIVE

The novel Outcome Measures in Rheumatology Clinical Trials (OMERACT) scoring system was used to evaluate the diagnostic effectiveness of major salivary gland ultrasonography (SGUS) for Sjögren's syndrome (SS).

MATERIALS AND METHODS

SGUS was performed on the parotid glands (PGs) and submandibular glands of 242 patients (145 patients with SS and 97 patients without SS) using the OMERACT scoring system (grade 0-3). We also evaluated the association of SGUS scores with unstimulated whole salivary flow rate (UWSF), stimulated whole salivary flow rate (SWSF), and labial salivary gland biopsy (LSGB) results.

RESULTS

The SGUS scores were significantly higher for the SS group than for the non-SS group (p < 0.001). Using a cutoff value of 8 for the total score yielded the highest sensitivity (76%), specificity (90%), and area under the receiver operating characteristic curve (AUC, 0.828). The correlation between SGUS scores and salivary gland function was moderate to good. A cutoff value of 10 for the total score was more effective in predicting SWSF outcomes than UWSF outcomes (sensitivity: 73% > 58%, specificity: 98% > 87%, and AUC: 0.856 > 0.723). The association of OMERACT scores with LSGB results was fair to moderate. Among 61 anti-SSA-negative patients, 17 had positive PG scores (including ten SS and seven non-SS patients), and 44 had negative PG scores (including 37 non-SS and seven SS patients).

CONCLUSION

The OMERACT scoring system had good sensitivity and excellent specificity, demonstrating excellent diagnostic potential for SS and efficacy in assessing salivary gland function. Negative SGUS results may help reduce unnecessary biopsies in anti-SSA-negative patients.

[Evaluation of morphological activity of primary Sjogren's syndrome on bioptates of minor salivary glands]

BACKGROUND

The results of the morphological study of the minor salivary glands can be used to assess the activity of the primary Sjogren's syndrome and to decide on adequate therapy.The existing protocol of The Sjögren's International Clinical Collaborative Alliance (SICCA) prescribes the methodology for examining biopsy specimens for suspected Sjögren's disease, however, experts interpret data from the analysis of histological preparations differently.

OBJECTIVE

To identify morphological forms of sialadenitis, as well as to determine the focus score in Russian patients based on the retrospective analysis of minor salivary glands biopsies of patients with primary Sjogren's syndrome.

MATERIAL AND METHODS

Biopsies of minor salivary glands were studied in 92 patients with primary Sjogren's syndrome and 42 patients without rheumatic disease.

RESULTS

Focal lymphocytic sialadenitis was detected in 69 patients with primary Sjogren's syndrome. The focus score in patients with primary Sjogren's syndrome was 7.32 (2.8-14.17). In patients without rheumatic diseases, this index was 0.48 (p<0.05). Patients with confluent lymphocytic foci need immunohistochemical examination and dynamic monitoring to exclude lymphoproliferative diseases.

CONCLUSION

The index of morphological activity of sialadenitis in primary Sjogren's syndrome ranges from 2.8 to 14.17 and reflects the activity of the underlying disease.It should be taken into account in the diagnosis and prescription of adequate therapy. Further study of the correlations of morphological and clinical and laboratory parameters will lead to clarification of the criterion signs of the disease.

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.