Characteristics of Chinese patients with primary Sjögren's syndrome: preliminary report of a multi-centre registration study

Identification and Validation of IFI44 as a Novel Biomarker for Primary Sjögren's Syndrome

Background

Primary Sjögren's syndrome (pSS) is an autoimmune condition marked by lymphocyte infiltration in the exocrine glands. Our study aimed to identify a novel biomarker for pSS to improve its diagnosis and treatment.

Methods

The gene expression profiles of pSS were obtained from the Gene Expression Omnibus (GEO) database. The specific differentially expressed genes (DEGs) were screened by the Least Absolute Shrinkage and Selection Operator (LASSO), Random Forest (RF), and Recursive Feature Elimination with Support Vector Machines (SVM-RFE). A biomarker was picked out based on correlation and diagnostic performance, the connection between the biomarker and clinical traits and immune infiltrating cells was explored, and the biomarker's protein expression level in the serum of pSS patients was detected by enzyme-linked immunosorbent assay (ELISA). The competitive endogenous RNA (ceRNA) network regulated by the biomarker was predicted to verify the reliability of the biomarker in diagnosing pSS.

Results

IFI44, XAF1, GBP1, EIF2AK2, IFI27, and IFI6 showed prominent diagnostic ability, with the high accuracy (AUC = 0.859) and significance (R ≥ 0.8) of IFI44 within the training dataset. IFI44 strongly exhibited a negative correlation with resting NK cells, macrophages M0, and eosinophils, and a positive correlation with activated dendritic cells, naive B cells, and activated CD4 memory T cells. Furthermore, IFI44 was significantly positively correlated with clinical traits such as IgG, SSA, SSB, ANA, and ESSDAI, with its protein expression level in the serum of pSS patients being notably elevated compared to controls (p < 0.001). Finally, the ceRNA regulatory network showed that hsa-miR-944, hsa-miR-9-5p, hsa-miR-126-5p, and hsa-miR-335-3p were significantly targeted IFI44, suggesting that IFI44 may serve as a dependable biomarker for pSS.

Conclusion

In this study, we dug out IFI44 as a biomarker for pSS, systematically studied the potential regulatory mechanism of IFI44, and verified its reliability as a biomarker for pSS.

Recommendations on cutaneous and hematological manifestations of Sjögren's disease by the Brazilian Society of Rheumatology

Sjogren's disease (SjD) is an autoimmune disease that is characterized not only by the sicca symptoms it causes but also by its systemic nature, which is capable of several and not yet fully understood extraglandular manifestations. To gain a clearer understanding of these manifestations as well as a better practical approach, a panel of experts from the Brazilian Society of Rheumatology conducted a systematic review and meta-analysis on the identification of epidemiologic and clinical features of the extraglandular manifestations present in ESSDAI (EULAR Sjogren´s syndrome disease activity index), followed by a voting panel with recommendations for clinical practice. This publication is complementary to others already published and covers cutaneous and hematological manifestations, with prevalence data generated by a meta-analysis of 13 clinical or laboratory manifestations and 6 clinical management recommendations.

Epidemiology of Sjögren's: A Systematic Literature Review

INTRODUCTION

Primary Sjögren's is a multi-system autoimmune disease affecting patients' physical, mental, and emotional wellbeing. The epidemiology of Sjögren's is not well understood, and up-to-date epidemiological evidence is needed to improve knowledge and awareness of Sjögren's among patients and healthcare professionals, and to ascertain the global burden of disease. The objective of this research was to conduct a de novo systematic literature review (SLR) to identify and synthesise evidence on global epidemiology of primary Sjögren's.

METHODS

This SLR was conducted in May 2021 by searching MEDLINE and Embase databases, relevant conference proceedings, websites of registries, and health technology assessment agencies and databases. Publications were systematically screened for English language articles reporting on the incidence, prevalence, age at symptom onset, and age at diagnosis for people with primary Sjögren's.

RESULTS

Of 3510 records identified, 68 publications were included, representing 62 unique studies. Studies reported on age at symptom onset (16/62; 25.8%) and age at diagnosis (43/62; 69.4%) more frequently than incidence (7/62; 11.3%) and prevalence (9/62; 14.5%). Primary Sjögren's was found to have the highest incidence and prevalence in females and in older age groups (incidence: ≥65 years; prevalence: ≥75 years). Average age at onset and diagnosis of primary Sjögren's ranged between 34-57 years and 40-67 years, respectively.

CONCLUSIONS

This SLR identified a paucity of incidence and prevalence data for primary Sjögren's, highlighting a need for further epidemiological studies. The global Sjögren's community must work together to follow the defined classification criteria of primary Sjögren's and reporting guidelines for incidence and prevalence data to allow for meaningful epidemiological comparisons across studies, settings, and countries.

Human umbilical cord mesenchymal stem cells improve disease characterization of Sjogren's syndrome in NOD mice through regulation of gut microbiota and Treg/Th17 cellular immunity

BACKGROUND

For the unclear pathogenesis of Sjogren's syndrome (SS), further exploration is necessary. Mesenchymal stem cells (MSCs) and derived exosomes (MSCs-exo) have exhibited promising results in treating SS.

OBJECT

This study aimed to investigate the effect and mechanism of human umbilical cord MSCs (UC-MSCs) on SS.

METHODS

Nonobese Diabetic (NOD) mouse splenic T cells were co-cultured with UC-MSCs and UC-MSCs-exo, and interferon-gamma (IFN-γ), interleukin (IL)-6, IL-10, prostaglandin E2 (PGE2), and transforming growth factor-β1 (TGF-β1) levels in the supernatant were assessed by quantitative real-time polymerase chain reaction and enzyme-linked immunosorbent assay. Co-cultured T cells were injected into NOD mice via the tail vein. The inflammatory cell infiltration in the intestine and the submandibular gland was characterized by hematoxylin-eosin staining. Treg/Th17 homeostasis within the spleen was determined by flow cytometry. Gut microbiota was detected by 16S rRNA sequencing, and the relationship between differential microbiota and Treg/Th17 cytokines was analyzed by the Pearson correlation coefficient.

RESULTS

UC-MSCs, UC-MSCs-exo, and NOD mouse splenic T cells were successfully cultured and identified. After T cells were co-cultured with UC-MSCs and UC-MSCs-exo, both IFN-γ and IL-6 were decreased while IL-10, PGE2, and TGF-β1 were increased in transcriptional and translational levels. UC-MSCs and UC-MSCs-exo partially restored salivary secretion function, reduced Ro/SSA antibody and α-Fodrin immunoglobulin A levels, reduced inflammatory cell infiltration in the intestine and submandibular gland, raised proportion of Treg cells, decreased IFN-γ, IL-6, IL-2, IL-17, lipopolysaccharide, and tumor necrosis factor-alpha levels, and raised IL-10, Foxp3, and TGF-β1 levels by affecting co-cultured T cells. The intervention of UC-MSCs and UC-MSCs-exo improved intestinal homeostasis in NOD mice by increasing microbiota diversity and richness. Additionally, differential microbiota was significantly associated with Treg/Th17 cytokine levels.

CONCLUSION

Human UC-MSCs and UC-MSCs-exo improved disease characterization of SS in NOD mice through regulation of gut microbiota and Treg/Th17 cellular immunity.

Hyperglobulinemia predicts increased risk of mortality in primary Sjögren's syndrome: Based on a Chinese multicentre registry

OBJECTIVE

To investigate whether primary Sjögren's syndrome (pSS) patients with hyperglobulinemia have an increased risk of all-cause mortality.

METHODS

Patients who registered in the Chinese Rheumatism Data Centre from May 2016 to July 2021 and met the 2002 American European Consensus Group criteria or 2016 American College of Rheumatology /European League Against Rheumatism classification criteria for Sjögren's syndrome were included. Hyperglobulinemia was defined as any elevated serum levels of immunoglobulin G (IgG), immunoglobulin A (IgA), or immunoglobulin M (IgM). The primary outcome was all-cause death. Data for demographic and clinical characteristics, laboratory results, disease activity, damage scores, and treatments were evaluated.

RESULTS

A total of 9527 pSS patients were included in the analysis, of whom 4236 (44.5%) had at least one kind of elevated immunoglobulin level among IgG, IgA, and IgM. Patients with hyperglobulinemia had a significantly increased risk of death (crude hazard ratio 2.60; 95% confidence interval 1.91-3.55; adjusted hazard ratio 1.90; 95% confidence interval 1.20-3.01). The risk of death was positively correlated with IgG level (P trend <.001). The 5-, 10-, and 15-year survival rates of patients with hyperglobulinemia were 96.9%, 92.3%, and 87.9%, respectively, and significantly lower than the corresponding rates of 98.8%, 97.9%, and 96.4% in patients without hyperglobulinemia.

CONCLUSIONS

Hyperglobulinemia is an independent risk factor for increased all-cause mortality in pSS patients. The risk of death is positively correlated with IgG level.

Screening biomarkers for Sjogren's Syndrome by computer analysis and evaluating the expression correlations with the levels of immune cells

Background

Sjögren's syndrome (SS) is a systemic autoimmune disease that affects about 0.04-0.1% of the general population. SS diagnosis depends on symptoms, clinical signs, autoimmune serology, and even invasive histopathological examination. This study explored biomarkers for SS diagnosis.

Methods

We downloaded three datasets of SS patients' and healthy pepole's whole blood (GSE51092, GSE66795, and GSE140161) from the Gene Expression Omnibus (GEO) database. We used machine learning algorithm to mine possible diagnostic biomarkers for SS patients. Additionally, we assessed the biomarkers' diagnostic value using the receiver operating characteristic (ROC) curve. Moreover, we confirmed the expression of the biomarkers through the reverse transcription quantitative polymerase chain reaction (RT-qPCR) using our own Chinese cohort. Eventually, the proportions of 22 immune cells in SS patients were calculated by CIBERSORT, and connections between the expression of the biomarkers and immune cell ratios were studied.

Results

We obtained 43 DEGs that were mainly involved in immune-related pathways. Next, 11 candidate biomarkers were selected and validated by the validation cohort data set. Besides, the area under curves (AUC) of XAF1, STAT1, IFI27, HES4, TTC21A, and OTOF in the discovery and validation datasets were 0.903 and 0.877, respectively. Subsequently, eight genes, including HES4, IFI27, LY6E, OTOF, STAT1, TTC21A, XAF1, and ZCCHC2, were selected as prospective biomarkers and verified by RT-qPCR. Finally, we revealed the most relevant immune cells with the expression of HES4, IFI27, LY6E, OTOF, TTC21A, XAF1, and ZCCHC2.

Conclusion

In this paper, we identified seven key biomarkers that have potential value for diagnosing Chinese SS patients.

Predictive value of bone marrow megakaryocyte count for immunotherapeutic response in primary Sjögren's syndrome patients with severe immune thrombocytopenia: A single-center case-control study in China

OBJECTIVES

To investigate potential predictors of treatment response in primary Sjögren's syndrome (pSS) patients with severe immune thrombocytopenia (ITP), with a focus on bone marrow megakaryocyte (MK) count.

METHODS

This case-control study included patients with pSS and severe ITP who were admitted to Peking Union Medical College Hospital and met the 2002 AECG or 2016 American College of Rheumatology / European League Against Rheumatism criteria for SS. Patients who had overlap other connective tissue diseases and with thrombocytopenia that could be explained by other causes were excluded. Severe ITP was defined as platelet count <20 × 10⁹ /L. Response was evaluated at 3 months after treatment.

RESULTS

Sixty-eight eligible patients were included: 34 (50%) achieved complete remission (CR), 18 (26%) partial remission (PR) and 16 (24%) were non-responders (NRs). Fewer infections were found in the CR group (24%) than in the PR (50%) and NR (56%) groups (P = 0.04). The MK count (CR 32 vs PR 36 vs NR 4 per slide, P < 0.001) in the NR group was significantly lower than in the other groups. MK count >6.5 per slide predicted good treatment response, with 85.7% sensitivity, 88.1% specificity and 0.866 area under the curve. Logistic regression indicated that patients with more MKs were more likely to respond to immunotherapy (crude odds ratio [OR] 1.45, 95% CI 1.2-2.0, adjusted OR 1.68, 95% CI 1.2-2.7).

CONCLUSIONS

MK count predicted response to immunosuppressive treatment in pSS patients with severe ITP. These patients are recommended to have bone marrow aspiration before treatment initiation. Clinicians should be aware of screening for infections during clinical practice.

Renal tubular acidosis and associated factors in patients with primary Sjögren's syndrome: a registry-based study

OBJECTIVES

To investigate the clinical features and factors associated with primary Sjögren's syndrome (pSS)-associated renal tubular acidosis (RTA).

METHOD

This case-control study was based on a multicenter pSS registry established by the Chinese Rheumatism Data Center. Patients with pSS, including those with RTA and those without renal involvement, between May 2016 and March 2020 were included in the analysis. Demographic, clinical, and laboratory data were also collected. Univariate and multivariate logistic regression analyses were used to identify factors that were associated with pSS-RTA.

RESULTS

This study included 257 pSS patients with RTA and 4222 patients without renal involvement. Significantly younger age at disease onset (40.1 ± 14.1 vs. 46.2 ± 13.1 years, P < 0.001), longer diagnosis interval (15.0 interquartile range [IQR] [1.0, 48.0] vs. 6.0 IQR [0, 34.0] months, P < 0.001), higher EULAR Sjögren's syndrome disease activity index (9 IQR [5, 15] vs. 3 IQR [0, 8], P < 0.001), and a higher prevalence of decreased estimated glomerular filtration rate (25.0% vs. 6.6%, P < 0.001) were observed in pSS patients with RTA than in those without renal involvement. Factors that were independently associated with pSS-RTA included age at disease onset ≤ 35 years (odds ratio [OR] 3.00, 95% confidence interval [CI] 2.27-3.97), thyroid disorders (OR 1.49, 95% CI 1.04-2.14), subjective dry mouth (OR 3.29, 95% CI 1.71-6.35), arthritis (OR 1.57, 95% CI 1.10-2.25), anti-SSB antibody positivity (OR 1.80, 95% CI 1.33-2.45), anemia (OR 1.67, 95% CI 1.26-2.21), elevated alkaline phosphatase level (OR 2.14, 95% CI 1.26-3.65), decreased albumin level (OR 1.61, 95% CI 1.00-2.60), and elevated erythrocyte sedimentation rate (OR 1.78, 95% CI 1.16-2.73).

CONCLUSIONS

Delayed diagnosis and decreased kidney function are common in pSS patients with RTA. pSS should be considered in patients with RTA, and early recognition and treatment may be useful in slowing the deterioration of renal function in patients with pSS-RTA. Key Points • pSS patients with RTA have earlier disease onset and higher disease activity than pSS patients without RTA, but the diagnosis was frequently delayed. • Decreased kidney function are common in pSS patients with RTA. • Sjögren's syndrome should be considered in young female patients with unexplained RTA, whereas RTA should be screened in pSS patients with early disease onset and elevated ALP level.

Risk factors for hypertension in primary Sjögren's syndrome patients: a nomogram was constructed

Cardiovascular disease (CVD) is one of the main causes of death in primary Sjögren' s syndrome (pSS) patients, while hypertension is considered an independent risk factor for CVD in pSS patients and its prevalence is increased compared with the general population. In order to identify risk factors of hypertension in patients with pSS, this study included 293 pSS patients admitted in the Third People's Hospital of Chengdu from April 2011 to August 2020 and 195 pSS patients admitted in Sichuan Provincial People's Hospital from January 2011 to June 2018. The multiple logistic regression was used to screen risk factors and nomogram was drawn based on regression coefficients. Then C-index and calibration plot were used to estimate its discrimination and calibration, respectively. Compared with pSS patients without hypertension, those with hypertension were older, higher in blood pressure, longer in duration of pSS, and had higher rates of smoking, xerophthalmia, xerostomia, previous use of botanicals, NSAIDs, and statins. Moreover, they were more likely to have pulmonary interstitial fibrosis and had higher levels of serum lipids and renal function indicators (all P < 0.05). Finally, a nomogram based on four significant factors (age, duration of pSS, LDL-c, and anti-SSA antibody) was constructed. Its' C-index is 0.812 (95% CI: 0.754-0.870), and it shows a good calibration. C-index value of 0.721 and good calibration still could be reached in external verification. Clinicians can use it in pSS population for early detection of hypertension and if necessary, early preventive measures could be taken to reduce its occurrence.

Hsa_circ_0008301 as a potential biomarker of disease activity for primary Sjogren's syndrome: Increased expression in peripheral blood of patients with primary Sjogren's syndrome

OBJECTIVES

To explore the expression level, association with disease activity and clinical significance of hsa_circ_0008301 in the peripheral blood of patients with primary Sjögren's syndrome (pSS).

METHODS

We selected 70 pSS patients hospitalized under the Rheumatology service line at the General Hospital of Ningxia Medical University from September 2018 to June 2021 as the disease group, in which general data and clinical indicators were collected. Fifty-three patients with healthy physical examinations for the same period were selected as the healthy control group, and 32 patients with non-pSS rheumatic diseases were selected as the disease control group. We collected peripheral blood samples and used fluorescence quantitative PCR to detect the expression level of hsa_circ_0008301. In addition, we analyzed the association of the expression level of hsa_circ_0008301 with the clinical characteristics and disease activity of pSS patients. A receiver operating characteristic curve was used to evaluate the diagnosis and the disease activity value of hsa_circ_0008301 in patients with pSS. Meanwhile, we analyzed the differential expression of hsa_circ_0008301 in 24 pSS patients selected from the disease group before and after treatment.

RESULTS

The relative expression of hsa_circ_0008301 in the peripheral blood of pSS patients was significantly higher than that in the control groups including healthy control group and disease control group. The expression level of hsa_circ_0008301 was high in pSS patients with a course of disease ≥ 10 years, fatigue symptoms, platelets < 100*10^9/L, erythrocyte sedimentation rate ≥ 50 mm/h, immunoglobulin IgG > 16 g/L, complement C3 < 0.9 g/L, ESSDAI score ≥ 5 and positively correlated with the above groups. Furthermore, ROC analysis showed that hsa_circ_0008301 was statistically significant between pSS patients and healthy controls. We selected patients from the disease group before and after treatment and showed that the expression level of hsa_circ_0008301 decreased significantly after treatment, compared with before. The area under the curve (AUC) was 0.825 (95% CI: 0.754 ∼ 0.897; P < 0.0001). The AUC of hsa_circ_0008301 in pSS patients and the disease control group was 0.673 (95% CI: 0.563 ∼ 0.782; P = 0.005), the sensitivity was 40.00%, the specificity was 93.70%, the optimal truncation value was > 0.0420, and the maximum Youden index was 0.337. In addition, ROC analysis revealed that hsa_circ_0008301 was statistically significant between disease-active patients and stable patients. The AUC value was 0.681 (95% CI: 0.553 ∼ 0.809; P = 0.010), the sensitivity was 65.90%, the specificity was 72.40%, the optimal truncation value was > 0.0285, and the maximum Youden index was 0.383. ROC analysis indicated that hsa_circ_0008301 has some value in the diagnosis and disease activity of patients with pSS. Comparison of 24 pSS patients selected from the disease group before and after treatment showed that the expression level of hsa_circ_0008301 decreased significantly after treatment compared with before treatment (Z =  - 4.257, P < 0.0001). ROC analysis indicated that hsa_circ_0008301 has some value in the diagnosis and disease activity of patients with pSS.

CONCLUSIONS

Hsa_circ_0008301 is expressed in higher levels in the peripheral blood of patients with pSS, which is related to the disease activity. It may be involved in the occurrence and development of pSS and may have a potential biomarker for the disease.

[Evaluation of ocular surface status and function in primary Sjögren's syndrome with hypothyroidism]

OBJECTIVE

To explore the effect of hypothyroidism (HT) on the ocular surface status of patients with primary Sjögren's syndrome-related dry eye (pSS-DED).

METHODS

The cross-sectional study included 36 patients with pSS-DED who were treated at the dry eye clinic of Peking University Third Hospital from December 2020 to June 2021, of whom 12 were pSS-DED patients combined with HT. In the same period, 24 patients with simple dry eye disease (DED) were served as a control group. All the patients filled out the Ocular Surface Disease Index (OSDI) questionnaire, and performed tear film break-up time (BUT), Schirmer test, tear meniscus height, corneal/conjunctival fluorescein staining, meibomian gland secretion capacity, meibum evaluation and confocal microscope examination.

RESULTS

(1) Compared with pSS-DED and simple DED patients, pSS-DED +HT patients had lower average BUT [(2.7±0.8) s], Schirmer test [(4.9±4.8) mm] and tear meniscus height [(0.13±0.03) mm], and the difference was statistically significant (F=12.43, P < 0.01; F=6.96, P < 0.01; F=3.31, P < 0.05). (2) Compared with DED and pSS-DED patients, the meibomian gland secretion capacity and meibomian trait scores of pSS-DED+HT patients were mainly distributed in the high division. There were statistically significant differences in the distribution of secretion capacity of meibomian glands (χ²=10.72, P < 0.05) and meibomian trait assessment scores (χ²=8.34, P < 0.05) among the three groups. (3) Serum total thyroxine and serum free thyroxine levels in the pSS-DED+HT patients showed positive correlation (P < 0.05, P < 0.05) with their BUT (r=0.60, 0.60), Schirmer's test (r=0.64, 0.66) and tear river height (r=0.61, 0.62), independent of lid gland secretory capacity; no significant correlation was found between thyroid-stimulating hormone, anti-thyroglobulin antibody and lid gland secretory capacity. Thyroid hormone, anti-thyroglobulin antibody, and thyroid peroxidase antibody were not found to be significantly correlated with ocular surface status. (4) Compared with pSS-DED, the fiber density of the subbasal nerve plexus in pSS-DED+HT group decreased (t=2.06, P < 0.05), and the curvature score increased (t=2.13, P < 0.05).

CONCLUSION

The ocular surface condition of pSS-DED patients with HT is worse than that of pSS-DED and DED patients. The main manifestations are that tear secretion, tear film stability, secretory function of the meibomian glands, meibum trait and fiber density of the subbasal nerve plexus decrease while the curvature increases. The mechanism might be related to the decrease in thyroid hormone production.

Potential Mechanisms of White Peony against Primary Sjögren’s Syndrome Based on Network Pharmacology and Molecular Docking

Background

Multiple system and organ damage occurs with the continuous progression of primary Sjögren's syndrome (pSS), and the lack of specific drugs against this disease is a huge challenge. White peony (WP), a widely used traditional Chinese herb, has been confirmed to have a therapeutic value in pSS. However, the specific mechanisms of WP in the treatment of pSS are unknown.

Methods

The active ingredients and their targets in WP were searched on the Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform (TCMSP), and disease-related targets were collected from GeneCards, Online Mendelian Inheritance in Man (OMIM), and the Therapeutic Target Database (TTD). The overlapping targets were acquired by taking the intersection. A protein-protein interaction (PPI) network was structured using the STRING database. A disease-drug-ingredient-target (D-D-I-T) network was built using Cytoscape software. By filtering twice, core targets were acquired. Gene Ontology (GO) and Kyoto Encyclopedia Gene and Genome (KEGG) pathway enrichment analysis were accompanied by R packages. Finally, molecular docking was used to verify the abovementioned results.

Results

In total, we screened 88 WP-related targets, 1480 pSS-related targets, and 32 overlapping targets. D-D-I-T Network analysis displayed six main active ingredients of WP, which played a significant therapeutic role in pSS. Further topological analysis selected seven core target genes, including IL-6, TNF, PPARγ, AKT1, CASP3, NOS3, and JUN. GO and KEGG analysis were used to elucidate pharmacological mechanisms, mainly acting in the AGE-RAGE signaling pathway. Molecular docking proved that paeoniflorin bound well with core targets.

Conclusion

Our study revealed that IL-6, TNF, AKT1, CASP3, NOS3, and JUN may be pathogenic target genes, and PPARγ may be a protective target gene. The main active ingredients of WP mainly played a therapeutic role via the AGE-RAGE signaling pathway. These findings provide a fundamental and theoretical basis for the clinical application of WP.

The IL-33/ST2 Axis Promotes Primary Sjögren's Syndrome by Enhancing Salivary Epithelial Cell Activation and Type 1 Immune Response

The molecular mechanisms of primary Sjögren's syndrome (pSS) are poorly understood. In this study, we explored the role of the IL-33/ST2 axis in the development of pSS. In the mouse model of experimental Sjögren's syndrome, we found that the saliva flow rate at weeks 4 and 30 was preserved in IL-33^-/- and ST2^-/- mice, compared with that of wild-type mice. At week 30 of experimental Sjögren's syndrome induction, the histological score, anti-nuclear Ab levels, and numbers of Th1 and B cells in draining lymph nodes of the salivary gland were lower in the IL-33^-/- and ST2^-/- mice, whereas Th17 cells and regulatory T cells were not changed. Primary salivary gland epithelial cells expressed the IL-33 receptor ST2. After stimulation with rIL-33, salivary gland epithelial cells increased the transcriptional levels of CD86 and CCL2, accompanied by the activation of the NF-κB inflammatory pathway. There was a synergistic effect between rIL-33 and rIL-12 in augmenting the production of IFN-γ in CD4⁺ T cells. In the pSS patients, the expression of IL-33 was elevated in the labial salivary gland, with the number of IL-33⁺ cells positively correlated with the score of the EULAR (European Alliance of Associations for Rheumatology) Sjögren's syndrome disease activity index (ESSDAI). ST2 was highly expressed in the cytoplasm of ductal epithelial cells, with low levels of expression in lymphatic infiltration sites. Our data suggest that the IL-33/ST2 axis may promote the development of pSS by enhancing salivary epithelial cell activation and the type 1 immune response.

Is Chinese herbal formula (nourishing Yin therapy) effective and well tolerated as an adjunct medication to hydroxychloroquine in the treatment of primary Sjögren's syndrome? A meta-analysis of randomised controlled trials

Background:

Previously, data mining methodology was used to identify 71 patented prescriptions in Chinese patent databases, indicating that Yin-nourishing therapy (YNT) may be an adjunct medication to hydroxychloroquine in the treatment of primary Sjögren’s syndrome (pSS). The purpose of this study was to investigate effects of the addition of YNT, which includes tonifying liver and kidney therapy (TLKT) and replenishing Qi and nourishing Yin therapy (RQNYT), in the treatment of pSS.

Methods:

Fourteen databases (including Chinese, English, Japanese, Korean and Latin databases) were searched to identify randomised controlled trials (RCTs) of YNT plus hydroxychloroquine (YNTPH) versus hydroxychloroquine alone in patients with pSS. Relevant publications up to June 2021 were selected. A meta-analysis and trial sequential analysis (TSA) were performed using Review Manager 5.3, Stata 14.0 and TSA 0.9 software. The quality of identified studies was assessed based on the Cochrane risk of bias tool and GRADE (grading of recommendations, assessment, development and evaluation) criteria.

Results:

We included five RCTs with a total of 345 participants. Pooled results indicated significant differences in short-term outcomes, which were assessed via European League Against Rheumatism (EULAR) Sjögren’s Syndrome Patient Reported Index (ESSPRI), EULAR Sjögren’s Syndrome Disease Activity Index (ESSDAI), tear production, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and immunoglobulin G (IgG) results when YNTPH was compared with hydroxychloroquine use alone (p < 0.05). No significant difference in salivary flow rate was reported. The most common side effect reported for both groups was gastrointestinal reaction. Sensitivity analyses suggested that heterogeneity might be ascribed to clinical methodology. Subgroup analyses revealed heterogeneities regarding salivary flow rate were eliminated. TLKT appeared to be better than RQNYT for improving salivary flow rate. TSA only supported changes in ESSPRI, ESSDAI and ESR values. For all studies, the quality of evidence was low.

Conclusion:

YNTPH may be an effective complementary therapy. Current evidence, however, is insufficient for determining whether YNTPH is more effective than hydroxychloroquine alone. Well-designed RCTs are needed to determine the role of YNT in pSS treatment.

Cancer incidence in primary Sjögren's syndrome: Data from the French hospitalization database

The relationship between cancer and primary Sjögren's syndrome (pSS) is uncertain. While the increased risk of hematological malignancies is well-known, data on the comparative incidence of solid neoplasms is conflicting. This study aimed to explore the associations between cancer and pSS. This nationwide population-based retrospective study from the French health insurance database (PMSI) evaluated patients hospitalized with new-onset pSS from 2011 to 2018 against age- and sex-matched hospitalized controls (1:10). The incidence of hematological malignancies and solid neoplasms was compared between the two groups. Mortality and multiple cancer incidence were also evaluated. Adjusted Hazard Ratios (aHR) calculations included confounding factors, such as low socioeconomic status. Among 25,661 hospitalized patients with pSS versus 252,543 matched patients (median follow-up of 3.96 years), we observed a higher incidence rate of lymphomas (aHR, 1.97 [95% CI, 1.59-2.43]), Waldenström macroglobulinemia (aHR, 10.8 [6.5-18.0]), and leukemia (aHR, 1.61 [1.1-2.4]). Thyroid cancer incidence was higher (aHR, 1.7 [1.1-2.8]), whereas bladder and breast cancer incidences were lower (aHR, 0.58 [0.37-0.89] and 0.60 [0.49-0.74], respectively). pSS patients with breast cancer exhibited a lower mortality rate. A limitation was that the database only encompasses hospitalized patients, and immunological and histological details are not listed. We confirmed the increased risk of hematological malignancies and thyroid cancers among patients with pSS. The lower risk of breast cancer suggests a role of hormonal factors and raises questions of the concept of immune surveillance within breast tissue. Epidemiological and translational studies are required to elucidate the relationships between pSS and cancer.

The Efficiency of Hydroxychloroquine for the Treatment of Primary Sjögren's Syndrome: A Systematic Review and Meta-Analysis

Objectives: This meta-analysis was conducted to evaluate the effects of hydroxychloroquine (HCQ) in the treatment of primary Sjögren's syndrome (pSS). Methods: Nine databases were searched for data collection. We used clinical features, including involvement in superficial tissues and visceral systems, and experimental findings, including Schirmer's test, unstimulated salivary flow rate (uSFR), C-reactive protein (CRP), erythrocyte sedimentation rate (ESR) and immunoglobulins (IgG, IgM and IgA) as major outcome measures. The Downs and Black quality assessment tool and RevMan 5.3 were used to assess the methodological quality and statistical analysis, respectively. Results: Thirteen studies with pSS patients, consisting of two randomized controlled studies, four retrospective studies and seven prospective studies were analyzed. Results showed that HCQ treatment significantly improved the oral symptoms of pSS patients compared to non-HCQ treatment (P = 0.003). Similar trends favoring HCQ treatment were observed for uSFR (p = 0.05), CRP (p = 0.0008), ESR (p < 0.00001), IgM (p = 0.007) and IgA (p = 0.05). However, no significant improvement was observed in other clinical features, including ocular involvement, fatigue, articular lesions, pulmonary, neurological and lymphoproliferative symptoms, renal organs and other experimental parameters in the HCQ treatment group compared to the non-HCQ treatment group. Conclusion: HCQ treatment showed moderate efficacy to improve oral symptoms, uSFR, ESR, CRP, IgM and IgA. However, HCQ could not alleviate organ-specific systemic involvement. Systematic Review Registration:We have registered on the PROSPERO [https://www.crd.york.ac.uk/PROSPERO/], and the registration number is identifier [CRD42020205624].

The Multiple Roles of B Cells in the Pathogenesis of Sjögren's Syndrome

Primary Sjögren’s syndrome (pSS) is a chronic autoimmune disease characterized by lymphocytic infiltration and tissue destruction of exocrine glands such as salivary glands. Although the formation of ectopic lymphoid tissue in exocrine glands and overproduction of autoantibodies by autoreactive B cells highlight the critical involvement of B cells in disease development, the precise roles of various B cell subsets in pSS pathogenesis remain partially understood. Current studies have identified several novel B cell subsets with multiple functions in pSS, among which autoreactive age-associated B cells, and plasma cells with augmented autoantibody production contribute to the disease progression. In addition, tissue-resident Fc Receptor-Like 4 (FcRL4)⁺ B cell subset with enhanced pro-inflammatory cytokine production serves as a key driver in pSS patients with mucosa-associated lymphoid tissue (MALT)-lymphomas. Recently, regulatory B (Breg) cells with impaired immunosuppressive functions are found negatively correlated with T follicular helper (Tfh) cells in pSS patients. Further studies have revealed a pivotal role of Breg cells in constraining Tfh response in autoimmune pathogenesis. This review provides an overview of recent advances in the identification of pathogenic B cell subsets and Breg cells, as well as new development of B-cell targeted therapies in pSS patients.

Stimulated whole salivary flow rate: The most appropriate technique for assessing salivary flow in Sjögren syndrome

BACKGROUND

We sought to determine the most appropriate method for measuring salivary flow to aid the diagnosis of Sjögren's syndrome (SS). Specifically, we compared the unstimulated whole salivary flow rate (UWSFR) with the stimulated whole salivary flow rate (SWSFR).

MATERIAL AND METHODS

This case-control study comprised one group of 103 patients with SS and a control group of 50 healthy people. We measured the UWSFR and SWSFR in both groups according to the guidelines established by Navacet [1993].

RESULTS

The UWSFR and SWSFR were significantly lower in the patient group compared with the controls (p < 0.01). Among the participants in the patient group, we found a decreased UWSFR in 84 individuals (81.5%) and a decreased SWSFR in 90 individuals (87.4%). We encountered difficulties obtaining saliva in 37 (35.9%) patients during the UWSFR test, and in 12 (11.7%) patients during the SWSFR test. There was no significant statistical difference in the UWSFR or SWSFR between patients with primary and secondary SS.

CONCLUSIONS

Compared with the UWSFR, the SWSFR is a more suitable and effective method for measuring salivary flow in patients with SS, as well as for qualitative analysis of the obtained saliva.

Factors Associated With Renal Involvement in Primary Sjögren's Syndrome: A Meta-Analysis

Background: Renal impairment is a critical complication in primary Sjögren's syndrome (pSS), resulting in chronic renal disease and even death. This meta-analysis was designed to find out the relevant factors of renal involvement in pSS.

Methods: PubMed, EMBASE, Cochrane Library, Scopus, and Web of Science were systemically searched until August 30, 2019. Studies were selected according to inclusion criteria, and data was extracted by two researchers independently. The Newcastle-Ottawa Scale was applied for quality assessment. Random- and fixed-effects models were used in this meta-analysis based on the result of the heterogeneity test. Meanwhile, a sensitivity analysis was conducted to investigate the cause of heterogeneity. Publication bias was shown in the funnel plot and evaluated further by Begg's and Egger's tests.

Results: Of the 9,989 articles identified, five articles enrolling 1,867 pSS patients were included in the final analysis, 533 with and 1,334 without renal involvement. There was no statistical significance in age and gender between these two groups. According to the meta-analysis, anti-SSB antibody, and arthralgia showed a significant association with renal involvement in pSS, the overall odds ratio (OR) values of which were 1.51 (95% CI, 1.16–1.95) and 0.59 (95% CI, 0.46–0.74), respectively. On the other hand, the overall OR values of anti-SSA antibody, rheumatoid factor, dry eyes, and labial salivary gland biopsy were just 0.90 (95% CI, 0.49–1.64), 1.05 (95% CI, 0.59–1.86), 0.60 (95% CI, 0.34–1.06), and 1.38 (95% CI, 0.98–1.95), respectively.

Conclusion: The presence of anti-SSB antibody is positively associated with renal involvement in pSS, while arthralgia is inversely associated. Large-scale prospective cohort studies are needed in the future to identify further risk factors.

Clinical features and outcomes from the Singapore Sjögren's syndrome study

OBJECTIVE

To study the clinical features, treatment and outcomes of primary Sjögren's Syndrome (pSS) in a Singapore cohort from an outpatient rheumatology clinic.

METHODS

Computerised Physician Order entry records of patients who fulfilled the 2016 ACR-EULAR classification criteria for pSS between 1993 and 2013 were retrospectively analysed.

RESULTS

There were 102 patients, of which 96 (94.1%) were females, and 91 (89.2%) Chinese. Mean age at diagnosis was 49.3 ± 11.8 years, mean disease duration was 9.0 ± 4.6 years. The most common manifestations were keratoconjunctivitis sicca (99.0%), xerostomia (96.1%), arthralgia/arthritis (56.9%). Exocrine glandular enlargement comprised parotidomegaly (28, 27.5%), with concurrent submandibular and lacrimal gland enlargement in one. The nervous system (15.7%) was the most commonly affected internal organ, with peripheral nervous system (peripheral neuropathy, mononeuritis multiplex) involvement more common than central. Hydroxychloroquine was most frequently used (88.2%), followed by methotrexate (7.8%) and azathioprine (6.9%). Pulsed intravenous (IV) methylprednisolone 500 mg/day for 3 days was used in 5 patients followed by oral (4) or IV cyclophosphamide (1) for cardiomyopathy and interstitial lung disease (1), and neurological involvement (4). These comprised neuromyelitis optica, transverse myelopathy, cranial neuropathy, mononeuritis multiplex and/or peripheral neuropathy alone or in combination. Intravenous immunoglobulins (2.0%) was used for sensory neuropathy and mononeuritis multiplex; rituximab (1.0%) in 1 patient for treatment of non-Hodgkin's B-cell lymphoma. There were no deaths.

CONCLUSION

Musculoskeletal manifestations were common, with the nervous system (peripheral more than central) the most common internal organ involved. Lymphoma was uncommon despite up to one-third of the cohort developing glandular enlargement.

Thyroid Function in 35 Patients with Gitelman Syndrome

Objective. In this study, we aimed to analyze thyroid function and related risk factors for thyroid dysfunction in 35 patients with Gitelman syndrome (GS). Methods. This study included 35 patients with GS who were referred to West China Hospital of Sichuan University from Aug 2013 to Jan 2018. General patient characteristics were collected, and thyroid function was assessed. To evaluate the potential contribution of hypokalemia to thyroid dysfunction, 636 patients who were clinically diagnosed with primary aldosteronism (PA) during the same period were included as the control group; these patients were divided into a hypokalemia group ( $N=528$ ) and a normokalemia group ( $N=108$ ). Logistic regression was used to screen for significant determinants of thyroid dysfunction in the GS patients. Results. Patients with GS had a significantly different prevalence of subclinical hypothyroidism, hypothyroidism, and hyperthyroidism than patients with hypokalemic PA and normokalemic PA (28.6%, 2.9%, and 11.4% vs. 15.5%, 6.1%, and 0.7% vs. 8.3%, 4.6%, and 2.8%, $P<0.001$ ). No significant difference was observed in the distribution of thyroid function between the hypokalemic PA group and the normokalemic PA group ( $P>0.05$ ). No significant differences were seen in the positive rates of thyrotropin receptor antibody (TRAb), thyroglobulin antibody (TGAb), and thyroid peroxidase antibody (TPOAb) among the three groups ( $P>0.05$ ). In the logistic regression, only sex (OR, 7.4; 95% CI, 1.555-35.479; $P=0.012$ ) was significantly correlated with thyroid dysfunction in GS patients. Conclusion. GS is complicated with a greater rate of thyroid dysfunction than primary aldosteronism. The risk of thyroid dysfunction in female patients with GS is higher than that in male patients.

Myasthenia Gravis Coexisting With Primary Sjögren's Syndrome: Report of Three Cases and Literature Review

Objective: The coexistence of myasthenia gravis (MG) and primary Sjögren's syndrome (pSS) is rarely reported. This study aims to describe the clinical features, treatment and outcome of MG coexisting with pSS.

Materials and Methods: Herein we reported three cases with the two coexisting diseases, and also searched the PubMed, Medline databases, and China Wanfang databases for the relevant case reports written in English, Chinese, or Japanese with detailed data.

Results: We reviewed a total of 17 patients with both diseases. Fifteen patients were female. The median age at onset was 48 years (range 28–78 years). MG was the initial disease in nine of 17 cases. The median interval between the onsets of the two diseases was 30 months (range 7 months to 20 years). The symptoms of MG included fatigable ptosis (64.7%), bulbar symptoms (58.8%), muscle fatigability (64.7%), diplopia (64.7%), dyspnea (23.5%), and facial paralysis (5.9%). Anti-acetylcholine receptor antibody was positive in 70.6% patients. All the patients had sicca symptoms. Manifestations of pSS also included swollen exocrine glands (23.5%), joint pain (23.5%), hair loss (11.8%), leukopenia (11.8%), recurrent oral ulcers (5.9%), Raynaud phenomenon (5.9%), and fever (5.9%). ANA positivity was present in 70.6% patients, anti-SSA positivity in 47.1%, and double positivity of anti-SSA and anti-SSB in 17.6%. There were 12 patients (70.6%) with two autoimmune diseases (pSS and MG), and five patients with more than two autoimmune diseases. Cholinesterase inhibitors were the most commonly prescribed drugs (82.4%). Seven patients received thymectomy and one patient improved after the operation. Two patients were given intravenous methylprednisolone pulse therapy, and four patients oral steroids combined with immunosuppressants initially. Intravenous immunoglobulin and plasma exchange were used in two patients, respectively, for the respiratory failure. All the patients improved following treatment except one patient who died of MG crisis due to medication withdrawal.

Conclusion: The coexistence of SS with MG is quite rare. The onset of MG may occur before or after the diagnosis of SS. Co-morbidity with MG does not seem to adversely affect the course of SS. Thus, controlling the progress of MG is the critical aspect of treatment.