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.

Repertoire Analysis of B-Cells Located in Striated Ducts of Salivary Glands of Patients With Sjögren's Syndrome

A major complication of primary Sjögren's syndrome (pSS) is development of mucosa associated lymphoid tissue (MALT) B-cell lymphoma, particularly in salivary glands. These lymphomas express FcRL4 and are characteristically associated with lymphoepithelial lesions. Neoplastic B-cells may be derived from non-neoplastic glandular intraductal B-cells, also virtually all expressing FcRL4. A characteristic feature of MALT lymphomas is the production of rheumatoid factors (RFs), which are largely encoded by stereotypic immunoglobulin variable heavy chain (IGHV) sequences. The aim of this study was to examine whether there is a relationship between the intraductal and periductal B-cells and whether the intraductal B-cells are selected for RF. RNA was extracted from laser-microdissected infiltrated ductal areas and periductal infiltrates from frozen parotid gland tissue sections of 5 pSS patients. PCR amplified IGHV transcripts were cloned into pCR™4-TOPO vector and subsequently sequenced. Microdissected ducts yielded 96 unique IGHV sequences derived from intraductal B-cells, while 119 unique IGHV sequences were obtained from periductal infiltrates. No major difference in VH-gene usage was observed between intraductal and periductal B-cells. Nearly all (>90%) IGHV sequences derived from both intraductal and periductal B-cells were mutated. Clonal expansions as defined by shared VDJ rearrangements were also present among both intraductal and periductal B-cells: in total 32 clones were found, from which 12 were located within ducts, 15 in periductal areas, and five clones shared members in both areas. We observed 12 IGHV rearrangements encoding for RF sequences from which two were derived from intraductal B-cells and 10 from periductal B-cells. Nine RF sequences were part of a clone. Together these findings indicate that intraductal and periductal B-cells are closely related to each other. Intraductal B-cells are most likely derived from periductal B-cells. We did not obtain evidence that RF-specific B-cells are enriched within the striated ducts. We speculate that in principle any activated B-cell can enter the striated ducts from the periductal infiltrate, irrespective of its antigenic specificity. Within the ducts, these B-cells may receive additional activation and proliferation signals, to further expand at these sites and by acquisition of driver-mutations develop toward lymphoma.

Geoepidemiology of Sjögren's syndrome in Latin America

OBJECTIVE

To evaluate the geoepidemiology of Sjögren's syndrome (SS) in Latin America.

METHODS

This was a three phase study in which original data from a Colombian cohort of patients with SS is presented, followed by a systematic review of Colombian and Latin American studies. Lastly, the geoepidemiology of SS in Latin America was assessed by comparing the clinical characteristics of the region with those of the rest of the world by means of a meta-analysis approach.

RESULTS

Data from 2970 patients from Latin America and 18019 patients from Europe, North America and Asia were analyzed. Colombian patients have a lower age at disease onset than those from other Latin American countries and a higher rate of positivity of antinuclear antibodies and rheumatoid factor. A significant difference in the proportion of female patients in Latin America compared with Europe and North America was observed. The spectrum of disease in Latin American was similar to North American patients, while strong differences were noticed between Latin American and European and Asian patients. Noteworthy, a paucity of reports including African and African-descendent patients was observed.

CONCLUSIONS

The clinical spectrum of SS differs between countries and continents. Genetic differences relying upon ancestry could explain these findings. However, environmental factors have proven to be important determinants in the development of autoimmune diseases (i.e., autoimmune ecology). Thus, ancestry and the autoimmune ecology should be considered in studies aimed to evaluate the geoepidemiology of SS and other autoimmune diseases.

Phosphatidylinositol 3-kinase delta pathway: a novel therapeutic target for Sjögren's syndrome

BACKGROUND

The phosphatidylinositol 3-kinase delta isoform (PI3Kδ) belongs to an intracellular lipid kinase family that regulate lymphocyte metabolism, survival, proliferation, apoptosis and migration and has been successfully targeted in B-cell malignancies. Primary Sjögren's syndrome (pSS) is a chronic immune-mediated inflammatory disease characterised by exocrine gland lymphocytic infiltration and B-cell hyperactivation which results in systemic manifestations, autoantibody production and loss of glandular function. Given the central role of B cells in pSS pathogenesis, we investigated PI3Kδ pathway activation in pSS and the functional consequences of blocking PI3Kδ in a murine model of focal sialoadenitis that mimics some features of pSS.

METHODS AND RESULTS

Target validation assays showed significant expression of phosphorylated ribosomal protein S6 (pS6), a downstream mediator of the phosphatidylinositol 3-kinase delta (PI3Kδ) pathway, within pSS salivary glands. pS6 distribution was found to co-localise with T/B cell markers within pSS aggregates and the CD138+ plasma cells infiltrating the glands. In vivo blockade of PI3Kδ activity with seletalisib, a PI3Kδ-selective inhibitor, in a murine model of focal sialoadenitis decreased accumulation of lymphocytes and plasma cells within the glands of treated mice in the prophylactic and therapeutic regimes. Additionally, production of lymphoid chemokines and cytokines associated with ectopic lymphoneogenesis and, remarkably, saliva flow and autoantibody production, were significantly affected by treatment with seletalisib.

CONCLUSION

These data demonstrate activation of PI3Kδ pathway within the glands of patients with pSS and its contribution to disease pathogenesis in a model of disease, supporting the exploration of the therapeutic potential of PI3Kδ pathway inhibition in this condition.

Shared Medical and Environmental Risk Factors in Dry Eye Syndrome, Sjogren's Syndrome, and B-Cell Non-Hodgkin Lymphoma: A Case-Control Study

Objectives

To assess whether there are shared exposures associated with Sjogren's syndrome (SS), dry eye syndrome (DES), and B-cell non-Hodgkin lymphoma (B-NHL), in order to determine whether they are etiologically related.

Methods

In a clinic-based case-control study, 702 participants (91 SS, 120 DES, 211 (age and sex frequency-matched) controls, and 280 B-NHL cases) were recruited and interviewed regarding exposures, medical history, and family history.

Results

Female predominance was noted in SS (ratio 9.2 : 1). Eye dryness was severest in SS compared to DES and controls (P < 0.001). Compared to controls, alcohol consumption was inversely associated with NHL, DES, and SS (odds ratio (OR) = 0.47, 95% confidence interval (CI): 0.31-0.71; OR = 0.54, 95% CI: 0.33-0.88; and OR = 0.26, 95% CI: 0.14-0.49, respectively), while a previous history of infection requiring hospitalization was positively associated with all three conditions: NHL (OR = 1.92; 95% CI: 1.23-2.99), DES (OR = 3.29; 95% CI: 1.97-5.47), and SS (OR = 4.74; 95% CI: 2.66-8.44). NHL patients were more likely to report first-degree relatives with hematologic cancer, while having first-degree relatives with an autoimmune disease (AID) was associated with SS (OR = 5.25; 95% CI: 2.59-10.63) and DES (OR = 3.55; 95% CI: 1.83-6.91) compared to controls.

Conclusions

Some exposures are associated with all three conditions (such as an inverse association with alcohol consumption and a positive association with serious past infection), while a family history of AID appears to be shared by DES and SS, but not NHL subjects. Shared risk factors for all three conditions indicate possible mutual etiological pathways.

Association between Helicobacter pylori infection and Sjögren syndrome: A meta-analysis

BACKGROUND

Helicobacter pylori has been proved as a risk factor of many diseases. There are some researches trying to find connection between H. pylori and Sjögren syndrome (SS). However, the conclusions of these studies are controversial. We conducted this meta-analysis to evaluate the association between H. pylori and SS.

METHODS

We searched PubMed and Embase databases for researches which include the data of H. pylori infection rate in SS and control groups. A fixed-effects model was used to analyze the risk odds ratio (OR) with 95% confidence intervals (CIs) according to the heterogeneity across the selected studies.

RESULTS

Nine studies with 1958 participants including 619 patients with SS met the inclusion criteria. The total infection rate of H. pylori was 53.83% (1054/1958). We found that the patients with SS had a significantly higher H. pylori infection rate than control groups (OR = 1.19, 95% CI: 1.01-1.41, P = .033). Subgroup analysis demonstrated a significantly higher H. pylori infection rate in patients with primary SS than controls (OR = 1.24, 95% CI: 1.03-1.50, P = .026).

CONCLUSION

This meta-analysis is the 1st meta-analysis about the association between H. pylori and SS. The pooled data suggested a significantly higher H. pylori infection rate in patients with SS. More prospective or multicenter retrospective researches could be conducted in the future.

Acquisition of N-Glycosylation Sites in Immunoglobulin Heavy Chain Genes During Local Expansion in Parotid Salivary Glands of Primary Sjögren Patients

Previous studies revealed high incidence of acquired N-glycosylation sites acquired N-glycosylation sites in RNA transcripts encoding immunoglobulin heavy variable region (IGHV) 3 genes from parotid glands of primary Sjögren’s syndrome (pSS) patients. In this study, next generation sequencing was used to study the extent of ac-Nglycs among clonally expanded cells from all IGVH families in the salivary glands of pSS patients. RNA was isolated from parotid gland biopsies of five pSS patients and five non-pSS sicca controls. IGHV sequences covering all functional IGHV genes were amplified, sequenced, and analyzed. Each biopsy recovered 1,800–4,000 unique IGHV sequences. No difference in IGHV gene usage was observed between pSS and non-pSS sequences. Clonally related sequences with more than 0.3% of the total number of sequences per patient were referred to as dominant clone. Overall, 70 dominant clones were found in pSS biopsies, compared to 15 in non-pSS. No difference in percentage mutation in dominant clone-derived IGHV sequences was seen between pSS and non-pSS. In pSS, no evidence for antigen-driven selection in dominant clones was found. We observed a significantly higher amount of ac-Nglycs among pSS dominant clone-derived sequences compared to non-pSS. Ac-Nglycs were, however, not restricted to dominant clones or IGHV gene. Most ac-Nglycs were detected in the framework 3 region. No stereotypic rheumatoid factor rearrangements were found in dominant clones. Lineage tree analysis showed in four pSS patients, but not in non-pSS, the presence of the germline sequence from a dominant clone. Presence of germline sequence and mutated IGHV sequences in the same dominant clone provide evidence that this clone originated from a naïve B-cell recruited into the parotid gland to expand and differentiate locally into plasma cells. The increased presence of ac-Nglycs in IGHV sequences, due to somatic hypermutation, might provide B-cells an escape mechanism to survive during immune response. We speculate that glycosylation of the B-cell receptor makes the cell sensitive to environmental lectin signals to contribute to aberrant B-cell selection in pSS parotid glands.

Germinal centres in diagnostic labial gland biopsies of patients with primary Sjögren's syndrome are not predictive for parotid MALT lymphoma development

OBJECTIVE

Patients with primary Sjögren's syndrome (pSS) have an increased risk of developing non-Hodgkin's lymphoma (NHL), particularly parotid gland mucosa-associated lymphoid tissue (MALT) lymphomas. Presence of germinal centres (GCs) in labial gland biopsies has been suggested as predictive factor for NHL. We assessed whether presence of GCs is increased in labial gland biopsies from patients with pSS who developed parotid MALT lymphoma, the dominant NHL-subtype in pSS, compared with patients with pSS who did not develop lymphoma.

METHODS

Eleven labial gland biopsies from patients with pSS that were taken prior to parotid MALT lymphoma development were compared with biopsies of 22 matched pSS controls (1:2) who did not develop lymphoma. Biopsies were evaluated for GCs (H&E and Bcl6).

RESULTS

Labial gland biopsies of pSS MALT lymphoma patients, revealed GCs in 2/11 (18%) H&E sections and 3/11 (27%) Bcl6 stained sections. In controls, GCs were present in 4/22 (18%) of H&E sections and 5/22 (23%) of Bcl6 stained sections.

CONCLUSION

Presence of GCs in labial gland biopsies does not differ between patients with pSS that develop parotid MALT lymphoma and patients with pSS who do not develop lymphoma. The presence of GCs in labial gland biopsies is therefore not a predictive factor for pSS-associated parotid MALT lymphomas.

Evaluation of ovarian reserve using anti-müllerian hormone and antral follicle count in Sjögren's syndrome: Preliminary study

AIM

The aim of this study was to determine ovarian reserve status using anti-müllerian hormone (AMH) level and antral follicle count (AFC) in patients with Sjögren's syndrome (SS).

METHODS

Twenty-four women with SS diagnosed according to the classification criteria proposed by the American-European Consensus Group and 25 healthy women as controls were enrolled in this study. Ovarian reserve was assessed on clinical findings, AFC, and serum AMH and reproductive hormone levels.

RESULTS

Compared with the healthy controls, in the SS patients, the duration of menstrual cycle was significantly shorter (P = 0.043); serum AMH (P = 0.001) and AFC (P = 0.001) were significantly lower, and serum luteinizing hormone (LH) was significantly higher (P = 0.019). The right (P = 0.555) and left ovarian (P = 0.386) volumes were also lower but this did not reach statistical significance. Serum follicle-stimulating hormone (P = 0.327), estradiol (P = 0.241), and prolactin (P = 0.55) were similar between the two groups.

CONCLUSIONS

Ovarian reserve may be reduced in SS patients. For the assessment of ovarian reserve, serum AMH and ovarian AFC with serum LH may be useful. Further studies with long-term follow-up are required to determine the course of ovarian reserve abnormalities and best possible biomarkers of reduced ovarian reserve in SS patients.

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

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

Towards inhibition of morbidity and mortality in Sjögren's syndrome: opportunities and challenges

In recent years considerable progress has been made in our understanding of the immunopathology of primary Sjögren's syndrome. Several genetic and environmental risk factors as well as cellular and molecular pathways have been identified, providing multiple targets for therapeutic strategies. Establishment of disease activity scores allows careful monitoring of therapeutic strategies and has set the stage for definition of clinical response criteria. Early detection of autoimmune symptoms before the onset of primary Sjögren's syndrome might trigger early intervention strategies to prevent immunopathology. New studies that indicated a strong association between lymphoid neogenesis and development of lymphoma and extra-glandular manifestations indicate that future therapeutic strategies should perhaps be directed at patients at risk for more severe disease. Several challenges remain, such as dissecting the causes and consequences of several types of IFN signatures or elucidating how viral triggering of the immune system is involved and could be targeted. The biggest challenge may be prevention of dryness since the causes of dryness remain elusive and could include non-immunological ones. In the coming years it will become clear to what extent novel drugs can prevent immunopathology and clinical symptoms like dryness and fatigue.