Primary versus Secondary Sjögren Syndrome: Is It Time To Reconsider These Terms?

Parasympathetic neurons derived from human pluripotent stem cells model human diseases and development

Autonomic parasympathetic neurons (parasymNs) control unconscious body responses, including "rest-and-digest." ParasymN innervation is important for organ development, and parasymN dysfunction is a hallmark of autonomic neuropathy. However, parasymN function and dysfunction in humans are vastly understudied due to the lack of a model system. Human pluripotent stem cell (hPSC)-derived neurons can fill this void as a versatile platform. Here, we developed a differentiation paradigm detailing the derivation of functional human parasymNs from Schwann cell progenitors. We employ these neurons (1) to assess human autonomic nervous system (ANS) development, (2) to model neuropathy in the genetic disorder familial dysautonomia (FD), (3) to show parasymN dysfunction during SARS-CoV-2 infection, (4) to model the autoimmune disease Sjögren's syndrome (SS), and (5) to show that parasymNs innervate white adipocytes (WATs) during development and promote WAT maturation. Our model system could become instrumental for future disease modeling and drug discovery studies, as well as for human developmental studies.

Epidemiology of Sjögren syndrome

Sjögren syndrome is a phenotypically varied autoimmune disorder that can occur alone in primary Sjögren syndrome or in association with other connective tissue diseases (CTDs), including rheumatoid arthritis, systemic lupus erythematosus (SLE) and systemic sclerosis (SSc). The estimation of the prevalence and incidence of Sjögren syndrome varies depending on diagnostic criteria and study design, making it difficult to estimate geographical and temporal trends. Nonetheless, disease phenotype is influenced by geographical origin, which is a risk factor for systemic activity. Whether mortality in primary Sjögren syndrome is increased compared with that of the general population is not yet known, but extra-glandular manifestations, in particular lymphomas, are clear risk factors for mortality. In CTDs associated with Sjögren syndrome, lymphoma risk seems higher than that of patients with CTD alone, and there is potentially lower disease activity in SLE with Sjögren syndrome and in SSc with Sjögren syndrome than in SLE or SSc alone.

Phases and Natural History of Sjögren's Disease: A New Model for an Old Disease?

Sjögren's disease (SjD) is an archetypal and heterogenous autoimmune disorder that is characterized by exocrine glandular dysfunction. A proportion of patients develop severe extraglandular manifestations, such as cryoglobulinemia, and have an increased risk of lymphoma, both of which can adversely affect quality of life and occasionally mortality. As with most autoimmune disorders, the pathogenesis is poorly understood and difficult to predict, and, frustratingly, there is a lack of targeted therapies to cure this disease. We review the disease manifestations of SjD and propose a staged model for understanding the evolution of pathology. In longitudinal studies, most patients remain relatively stable in terms of their laboratory and clinical parameters. However, in the setting of various risk factors, a proportion of patients develop severe symptoms and/or lymphoma. We discuss potential underlying mechanisms for disease progression and the strengths and limitations of using a staged model to correlate the pathogenesis and spectrum of manifestations in SjD. Ultimately, understanding how and why some patients remain relatively stable, whereas others progress and develop florid systemic disease and a fraction develop lymphoma, is key to developing preventative and therapeutic treatments.

Sjögren's Syndrome Treatments in the Microbiome Era

Sjögren's syndrome (SS) is a chronic autoimmune disease characterized by inflammatory cell infiltration of the salivary and lacrimal glands, resulting in acinar epithelial cell atrophy, cell death, and loss of exocrine function. At least half of SS patients develop extraglandular inflammatory disease and have a wide range of systemic clinical manifestations that can affect any organ system, including connective tissues. As many as 3.1 million people in the U.S. suffer from SS, a disease that causes severe impairment. Women are nine times more likely than men to be affected by this condition. Unfortunately, there is currently no effective treatment for SS, and the available options only provide partial relief. Treatment involves using replacement therapies such as artificial saliva and eye lubricants, or immunosuppressive agents that have limited efficacy. The medical community recognizes that there is a significant need for more effective treatments for SS. Increasing evidence demonstrates the links between the dysfunction of the human microbial community and the onset and development of many human diseases, signifying the potential use of microorganisms as an alternative strategy to conquer these issues. The role of the microbiome in controlling immune function of the human host in the context of autoimmune diseases like SS is now becoming better understood and may help to enable new drug development strategies. Natural probiotics and synthetic biology applications hold promise for novel treatment approaches to solve the encryption of many complex and multifactorial immune disorders, like SS.

Polyautoimmunity in systemic lupus erythematosus patients: New insights from a cross-sectional study

Objective

To assess the frequency of polyautoimmunity (PolyA) in a cohort of Colombian patients with systemic lupus erythematosus (SLE) and to identify associated factors.

Methods

This is an analytical cross-sectional study in a specialized center., a comprehensive review of the medical records of SLE patients was performed from 2015 to 2020 in order to obtain demographic, clinical data, laboratory, and treatment information. Associations between PolyA, demographic, and characteristics of the disease were explored.

Results

A total of 463 patients were included in the analysis. The average age was 47.3 ± 15 years. Most of this population were female (87.4%), whom were diagnosed with SLE in a long-term SLE (10.6 ± 10.1 years). Out of the total patients, 34.7% were diagnosed with PolyA. Among the most frequent clinical criteria for SLICC, arthritis (65%), kidney impairment (39.5%), and alopecia (34.8%) were found. The most frequent SLE-associated PolyA were antiphospholipid syndrome (APS) and Sjögren's syndrome (SS) (16.63% and 10.58%, respectively). PolyA-associated factors were age, xerophthalmia, central nervous system occlusion, and deep vein thrombosis (DVT). In contrast, renal impairment was significantly less frequent in PolyA patients after multivariate analysis.

Conclusion

The results have showed associated factors with PolyA like age, xerophthalmia, central nervous system occlusion, and deep vein thrombosis in this cohort. On the other hand, lupus nephritis was less frequent in patients with PolyA. This study provides a spotlight of a specific SLE population as real-life evidence for a better characterization of PolyA in the future.

Nucleic acid-sensing toll-like receptors: Important players in Sjögren’s syndrome

Sjögren’s syndrome (SS) is a chronic systemic autoimmune disease that affects the salivary and lacrimal glands, as well as other organ systems like the lungs, kidneys and nervous system. SS can occur alone or in combination with another autoimmune disease, such as systemic lupus erythematosus (SLE) or rheumatoid arthritis. The etiology of SS is unknown but recent studies have revealed the implication of the activation of innate immune receptors, including Toll-like receptors (TLRs), mainly through the detection of endogenous nucleic acids, in the pathogenesis of systemic autoimmune diseases. Studies on SS mouse models suggest that TLRs and especially TLR7 that detects single-stranded RNA of microbial or endogenous origin can drive the development of SS and findings in SS patients corroborate those in mouse models. In this review, we will give an overview of the function and signaling of nucleic acid-sensing TLRs, the interplay of TLR7 with TLR8 and TLR9 in the context of autoimmunity, summarize the evidence for the critical role of TLR7 in the pathogenesis of SS and present a possible connection between SARS-CoV-2 and SS.

Multi-Omic Biomarkers for Patient Stratification in Sjogren's Syndrome-A Review of the Literature

Sjögren's syndrome (SS) is a heterogeneous autoimmune rheumatic disease (ARD) characterised by dryness due to the chronic lymphocytic infiltration of the exocrine glands. Patients can also present other extra glandular manifestations, such as arthritis, anaemia and fatigue or various types of organ involvement. Due to its heterogenicity, along with the lack of effective treatments, the diagnosis and management of this disease is challenging. The objective of this review is to summarize recent multi-omic publications aiming to identify biomarkers in tears, saliva and peripheral blood from SS patients that could be relevant for their better stratification aiming at improved treatment selection and hopefully better outcomes. We highlight the relevance of pro-inflammatory cytokines and interferon (IFN) as biomarkers identified in higher concentrations in serum, saliva and tears. Transcriptomic studies confirmed the upregulation of IFN and interleukin signalling in patients with SS, whereas immunophenotyping studies have shown dysregulation in the immune cell population frequencies, specifically CD4⁺and C8⁺T activated cells, and their correlations with clinical parameters, such as disease activity scores. Lastly, we discussed emerging findings derived from different omic technologies which can provide integrated knowledge about SS pathogenesis and facilitate personalised medicine approaches leading to better patient outcomes in the future.

Sjögren's syndrome

Sjögren’s syndrome (SjS) is an autoimmune disease characterized by the triad of sicca symptoms, fatigue and pain. This diagnosis is usually made in women at the average age of 60 years. Diagnosis is made when sicca symptoms persist for more than three months, after the exclusion of possible differential diagnoses, and using the ACR/EULAR 2016 classification criteria for SjS. Many organs can be affected in the course of this disease. Xerosis cutis and pruritus are the most common skin manifestations, followed by leukocytoclastic vasculitis and subacute cutaneous lupus erythematosus. In addition, SjS patients often have myoarthralgia and neuropsychiatric symptoms. In the long term, attention must be paid to the increased risk of cardiovascular disease and lymphoma. Due to the multiorgan involvement in SjS patients, interdisciplinary care is required.

Hypokalemic Quadriparesis As Initial Presentation of Secondary Sjogren Syndrome With Associated Autoimmune Thyroiditis: A Case Report

Sjögren's syndrome is an autoimmune disorder typically presenting as dry mouth and eyes (sicca syndrome). However, the disease can involve any organ, complicating diagnosis. Renal involvement may manifest as distal renal tubular acidosis, leading to hypokalemia. We report a case of a 25-year-old woman presenting with progressive quadriparesis and vomiting. She had severe hypokalemic paralysis due to distal renal tubular acidosis. The patient was diagnosed with secondary Sjögren syndrome with autoimmune thyroiditis. She recovered completely with potassium supplementation.

Diagnostic value of salivary gland ultrasonography for secondary Sjögren syndrome in patients with systemic lupus erythematosus

BACKGROUND

Salivary gland ultrasound (SGUS) is a reliable technique for assessing the salivary glands in patients with primary Sjögren's syndrome (SS); however, the role of SGUS for diagnosis of secondary SS (sSS) in patients with systemic lupus erythematosus (SLE) was not examined.

OBJECTIVE

To assess the diagnostic value of SGUS for sSS in patients with SLE, and to investigate the relationship between SGUS findings with clinical and laboratory characteristics of patients with SLE.

PATIENTS AND METHODS

This cross-sectional study included 49 patients with SLE. The diagnosis of sSS was confirmed according to the 2016 ACR/EULAR criteria. Salivary gland US was performed for all patients and graded using a validated Hočevar scoring system. A complete clinical and laboratory workup for SLE was assessed. Schirmer's test and the ocular staining were performed.

RESULTS

Of the 49 patients with a mean age of 30.2 ± 9.6 years, 98% were female. 19 (38.8%) had sSS. SGUS changes consistent with sSS (≥17) were found in 29 (59.2%) of the patients. Patients with higher SGUS score had more sicca findings as well as positive anti-Ro, anti-La antibodies, and poorer psychological stress (p < 0.05). The SGUS (≥17) showed a sensitivity of 84.2% and a specificity of 56.7% for sSS diagnosis, with an area under the curve of 0.77 (95% CI: 0.63, 0.91).

CONCLUSION

We propose salivary gland ultrasound as a non-invasive method in the diagnostic workup for sSS in patients with SLE. Further studies to confirm the diagnostic value of SGUS in a larger sample of patients with sSS will be necessary.

Salivary Gland Function, Development and Regeneration

Salivary glands produce and secrete saliva, which is essential for maintaining oral health and overall health. Understanding both the unique structure and physiological function of salivary glands, as well as how they are affected by disease and injury will direct the development of therapy to repair and regenerate them. Significant recent advances, particularly in the OMICS field, increase our understanding of how salivary glands develop at the cellular, molecular and genetic levels; the signaling pathways involved, the dynamics of progenitor cell lineages in development, homeostasis and regeneration and the role of the extracellular matrix microenvironment. These provide a template for cell and gene therapies as well as bioengineering approaches to repair or regenerate salivary function.

Spatial transcriptomics of the lacrimal gland features macrophage activity and epithelium metabolism as key alterations during chronic inflammation

The lacrimal gland (LG) is an exocrine gland that produces the watery part of the tear film that lubricates the ocular surface. Chronic inflammation, such as Sjögren's syndrome (SS), is one of the leading causes of aqueous-deficiency dry eye (ADDE) disease worldwide. In this study we analyzed the chronic inflammation in the LGs of the NOD.B10Sn-H2b/J (NOD.H-2b) mice, a mouse model of SS, utilizing bulk RNAseq and Visium spatial gene expression. With Seurat we performed unsupervised clustering and analyzed the spatial cell distribution and gene expression changes in all cell clusters within the LG sections. Moreover, for the first time, we analyzed and validated specific pathways defined by bulk RNAseq using Visium technology to determine activation of these pathways within the LG sections. This analysis suggests that altered metabolism and the hallmarks of inflammatory responses from both epithelial and immune cells drive inflammation. The most significant pathway enriched in upregulated DEGs was the "TYROBP Causal Network", that has not been described previously in SS. We also noted a significant decrease in lipid metabolism in the LG of the NOD.H-2b mice. Our data suggests that modulation of these pathways can provide a therapeutic strategy to treat ADDE.

Therapeutic Potential of Anti-Interferon α Vaccination on SjS-Related Features in the MRL/lpr Autoimmune Mouse Model

Sjögren’s syndrome (SjS) is a frequent systemic autoimmune disease responsible for a major decrease in patients’ quality of life, potentially leading to life-threatening conditions while facing an unmet therapeutic need. Hence, we assessed the immunogenicity, efficacy, and tolerance of IFN-Kinoid (IFN-K), an anti-IFNα vaccination strategy, in a well-known mouse model of systemic autoimmunity with SjS-like features: MRL/MpJ-Faslpr/lpr (MRL/lpr) mice. Two cohorts (with ISA51 or SWE01 as adjuvants) of 26 female MRL/lpr were divided in parallel groups, “controls” (not treated, PBS and Keyhole Limpet Hemocyanin [KLH] groups) or “IFN-K” and followed up for 122 days. Eight-week-old mice received intra-muscular injections (days 0, 7, 28, 56 and 84) of PBS, KLH or IFN-K, emulsified in the appropriate adjuvant, and blood samples were serially collected. At sacrifice, surviving mice were euthanized and their organs were harvested for histopathological analysis (focus score in salivary/lacrimal glands) and IFN signature evaluation. SjS-like features were monitored. IFN-K induced a disease-modifying polyclonal anti-IFNα antibody response in all treated mice with high IFNα neutralization capacities, type 1 IFN signature’s reduction and disease features’ (ocular and oral sicca syndrome, neuropathy, focus score, glandular production of BAFF) improvement, as reflected by the decrease in Murine Sjögren’s Syndrome Disease Activity Index (MuSSDAI) modelled on EULAR Sjögren’s Syndrome Disease Activity Index (ESSDAI). No adverse effects were observed. We herein report on the strong efficacy of an innovative anti-IFNα vaccination strategy in a mouse model of SjS, paving the way for further clinical development (a phase IIb trial has just been completed in systemic lupus erythematosus with promising results).

Smoking, Obesity, and Risk of Primary Sjögren Syndrome

I read the paper by Servioli et al¹ conducting a 1:3 case-control study to evaluate the association between smoking status and primary (p-) Sjögren syndrome (SS). ORs (95% CIs) of current and former smokers compared to never smokers for pSS were 0.34 (0.14-0.85) and 1.27 (0.80-2.03), respectively. In contrast, there was no significant association of smoking status with antinuclear antibody, anti-SSA, anti-SSB, or rheumatoid factor positivity.

Emerging Role of microRNAs and Long Non-Coding RNAs in Sjögren's Syndrome

Sjögren’s Syndrome (SS) is a chronic autoimmune inflammatory disease. It is considered a multifactorial pathology, in which underlying genetic predisposition, epigenetic mechanisms and environmental factors contribute to development. The epigenetic regulations represent a link between genetic predisposition and environmental factors. Recent studies suggested a regulatory role for non-coding RNAs in critical biological and disease processes. Among non-coding RNAs, microRNAs (miRNAs) and long non-coding RNAs (lncRNAs) play a critical role in the post-transcriptional mRNA expression, forming a complex network of gene expression regulation. This review aims to give an overview of the latest studies that have investigated the role of miRNAs and lncRNAs in the SS. We included papers that investigated the expression of non-coding RNAs on different tissues, in particular on peripheral blood mononuclear cells and salivary glands. However, regarding the involvement of non-coding RNAs genetic variability in SS susceptibility very few data are available. Further research could help to elucidate underlying pathogenic processes of SS and provide new opportunities for the development of targeted therapies.

A 77-Year-Old Woman With Sjogren Syndrome Experiencing Progressive Dyspnea on Exertion and Nonproductive Cough

CASE PRESENTATION

A 77-year-old woman was referred to our interstitial lung disease unit. She presented with a history of progressive dyspnea on exertion and nonproductive, persistent cough over the previous year. She was diagnosed with Sjogren syndrome two years ago by a rheumatologist. In the context of Sjogren syndrome, she reported chronic xerostomia and xerophthalmia for the last 5 years. Her history was also notable for the presence of arterial hypertension and hypothyroidism. She denied the presence of shortness of breath, chest pain, arthralgia, muscle weakness, weight loss, night sweats, and fatigue. She reported exposure to house mold. There was no family history of respiratory diseases. The patient never smoked and denied alcohol consumption, illicit drug use, or any occupational exposures.

TLR7 Signaling Drives the Development of Sjögren's Syndrome

Sjögren’s syndrome (SS) is a chronic systemic autoimmune disease that affects predominately salivary and lacrimal glands. SS can occur alone or in combination with another autoimmune disease like systemic lupus erythematosus (SLE). Here we report that TLR7 signaling drives the development of SS since TLR8-deficient (TLR8ko) mice that develop lupus due to increased TLR7 signaling by dendritic cells, also develop an age-dependent secondary pathology similar to associated SS. The SS phenotype in TLR8ko mice is manifested by sialadenitis, increased anti-SSA and anti-SSB autoantibody production, immune complex deposition and increased cytokine production in salivary glands, as well as lung inflammation. Moreover, ectopic lymphoid structures characterized by B/T aggregates, formation of high endothelial venules and the presence of dendritic cells are formed in the salivary glands of TLR8ko mice. Interestingly, all these phenotypes are abrogated in double TLR7/8-deficient mice, suggesting that the SS phenotype in TLR8-deficient mice is TLR7-dependent. In addition, evaluation of TLR7 and inflammatory markers in the salivary glands of primary SS patients revealed significantly increased TLR7 expression levels compared to healthy individuals, that were positively correlated to TNF, LT-α, CXCL13 and CXCR5 expression. These findings establish an important role of TLR7 signaling for local and systemic SS disease manifestations, and inhibition of such will likely have therapeutic value.

Sjögren syndrome associated with protein-losing enteropathy: case-based review

The association between Sjögren's syndrome (SS) and protein-losing enteropathy (PLE) was scarcly reported. To analyze the clinical, therapeutic, and outcome characteristics of patients with SS and PLE and also to delineate the potential mechanisms and pathways connecting the gut to SS targeted organ's pathology. Systematic screening was conducted using PubMed/MEDLINE, LILACS, SciELO, Web of Science, and Cochrane, dating 1980 to 2020. SS and PLE were the key words. Eighteen patients with SS and PLE were summarized. The patient's ages ranged between 20 and 88 years, and only 4 were males. Primary SS was observed in most cases. Anti-Ro was detected in 100% of the cases while anti-La was reported in 64% of them. The clinical manifestations were protein loss, edema of the lower limbs, pleural effusion, ascites, facial edema, anasarca, diarrhea, and weight loss. Among these clinical manifestations, edema of the lower limbs was the most severe. Albumin concentration was 0.9-3.4 g/dL which increased to 2.8-4.3 g/dL after treatment. Small bowel biopsy was performed in all of the cases. Concerning the therapy, all the patients received systemic glucocorticoids. All of them improved. The period of onset of improvement ranged from 3 weeks to 36 months (an average of 3 months). The early diagnosis and appropriate therapy of PLE in patients with anti-Ro positive SS and who present edema, anasarca, or hypoalbuminemia is vital for a beneficial outcome. An excellent clinical improvement in all the cases was observed when treated early enough by cortico-therapy, thus preventing patient's deterioration, complications, and reducing morbidity and potential mortality.

Interstitial Pneumonia with Autoimmune Features (IPAF): A Single-Centre, Prospective Study

Objectives

Interstitial pneumonia with autoimmune features (IPAF) refers to patients with interstitial lung disease and autoimmune features not fulfilling the classification criteria for a specific connective tissue disease. We sought to study the characteristics, disease progression, response to treatment and complications of patients with IPAF in 1-year follow-up period.

Methods

Clinical and laboratory findings, comorbidities, medications, pulmonary function tests (PFTs), chest HRCT and complications during the one-year follow-up period were documented for each of the 39 enrolled patients with IPAF.

Results

The mean age at the time of IPAF diagnosis was 63.2 (±11) years, and 62% of patients were female. The most common clinical features were arthritis (82%) and rash (54%-not included in the IPAF criteria). Antinuclear antibodies (ANA) (59%) and non-specific interstitial pneumonia (NSIP-61.5%) were the most prevalent autoantibodies and radiological pattern respectively. PFTs at 12 months from baseline stabilized or improved in 79.5% of patients (p> 0.05). Infections were observed in 23.1% of patients during the first and in 12.8% during the second semester of follow-up. Two patients (5.1%) required hospitalization. All infections occurred in patients with non-usual interstitial pneumonia (UIP) pattern (p=0.02).

Conclusions

Arthritis and rash are among the most common features in IPAF suggesting rash could be included into IPAF criteria. Almost 80% of patients had stable/improved PFTs at the end of follow-up. Infections occurred mainly in the first semester of treatment and in patients with non-UIP radiological pattern probably due to higher doses of corticosteroids used in these patients.

Disease activity and patient-reported outcomes in patients with rheumatoid arthritis and Sjögren’s syndrome enrolled in a large observational US registry

The objective of this study was to compare rheumatoid arthritis (RA) disease activity and patient-reported outcomes (PROs) in a national sample of patients with RA with/without Sjögren’s syndrome (SS). Adults with RA from a large observational US registry (Corrona RA) with known SS status between 22 April 2010 and 31 July 2018 and a visit 12 (± 3) months after index date were identified (n = 36,256/52,757). SS status: determined from a yes/no variable reported at enrolment into the Corrona RA registry and follow-up visits. Index date: date that SS status was recorded (yes/no). Patients received biologic or targeted synthetic disease-modifying antirheumatic drugs as part of standard care. Patients with RA only were followed for ≥ 12 months to confirm the absence of SS. Patients were frequency- and propensity-score matched (PSM) 1:1 and stratified by disease duration and treatment response-associated variables, respectively. Clinical Disease Activity Index (CDAI) and PROs 12 months after index visit were compared in patients with and without SS. Baseline characteristics in 283 pairs of PSM patients were balanced. Mean change in CDAI score was numerically lower in patients with RA and SS than patients with RA only (8.8 vs 9.3). Reductions in PROs of pain, fatigue and stiffness were two- to threefold lower for patients with RA and SS versus RA only. Reductions in RA disease activity and RA-related PROs were lower in patients with RA and SS versus those with RA only. Our data indicate that SS adds to treatment challenges; physicians may wish to consider SS status when managing patients with RA.

Prevalence of Sjögren's syndrome associated with rheumatoid arthritis in the USA: an observational study from the Corrona registry

The objectives of this analysis were to assess the prevalence of Sjögren’s syndrome (SS) associated with rheumatoid arthritis (RA) and to compare baseline characteristics of patients with RA with and without SS. Adult patients with RA from a large observational US registry (Corrona RA), with ≥ 1 visit for assessment of SS status between 22 April 2010 and 28 February 2018, were considered. Patients with RA with versus without SS were compared. SS status was determined from a yes/no variable and reported at enrollment into the Corrona RA registry and follow-up visits. Outcomes were unadjusted prevalence of SS in patients with RA, prevalence of SS by RA disease duration, and baseline characteristics in patients with RA by SS status. Of 24,528 eligible patients, 7870 (32.1%) had a diagnosis of RA and SS. The unadjusted overall rate for SS prevalence in patients with RA was 0.30 (95% confidence interval 0.29, 0.31). SS prevalence increased with increasing RA duration. Patients with RA with versus without SS were more likely to be older, female, and seropositive; had a longer RA duration; higher disease activity; and a higher incidence of comorbidities (hypertension, cardiovascular disease, malignancies, and serious infections), erosive disease, and subcutaneous nodules at index date. Patients with RA and SS had a higher disease burden than those with RA only. The prevalence of SS increased as duration of RA increased. RA with SS was associated with seropositivity, more severe RA, extra-articular manifestations, and comorbidities.

Key Points • The overall prevalence of SS among patients with RA was 30%. • The prevalence of SS increased with increasing RA disease duration. • Identifying specific clinical characteristics of patients with RA with SS, such as a greater incidence of extra-articular manifestations and comorbidities, may help clinicians to better characterize this patient population.

Classification criteria for secondary Sjögren's syndrome. Current state of knowledge

Dryness of mucosa and eyes is the most recognizable symptom of Sjögren’s syndrome (SS). Secondary SS (sSS) is diagnosed when symptoms of SS coexist with other systemic connective tissue disease. The sSS is often identified based on the symptoms of dryness in the presence of other connective tissue disease, making the diagnosis of sSS very subjective. The goal of this work was to summarize previously used and current criteria for the diagnosis of sSS. Classification criteria for sSS, which are universally accepted standards, do not exist. The diagnosis of sSS still depends on the experience of the investigator. Histopathological examination of minor salivary glands appears to be crucial for characterization of patients with sSS due to a specific picture of the disease and repeatability of the test.