Mechanisms underlying sex differences in autoimmunity.

Autoimmune diseases are a leading cause of disability worldwide. Most autoimmune diseases occur more often in women than men, with rheumatic autoimmune diseases being among those most highly expressed in women. Several key factors, identified mainly in animal models and cell culture experiments, are important in increasing autoimmune disease in females. These include sex hormones, immune genes including those found on the X chromosome, sex-specific epigenetic effects on genes by estrogen and the environment, and regulation of genes and messenger RNA by microRNAs found in extracellular vesicles. Evidence is also emerging that viruses as well as drugs or toxins that damage mitochondria may contribute to increased levels of autoantibodies against nuclear and mitochondrial antigens, which are common in many autoimmune diseases. The purpose of this Review is to summarize our current understanding of mechanisms that may determine sex differences in autoimmune disease.

IL-27 promotes pathogenic T cells in a mouse model of Sjögren's disease.

Sjögren's disease (SjD) is a chronic autoimmune disease characterized by focal lymphocytic inflammation in lacrimal and salivary glands. We recently identified IL-27 as a requisite signal for the spontaneous SjD-like manifestations in nonobese diabetic (NOD) mice. Here, we define T cell-intrinsic effects of IL-27 in lacrimal gland disease in NOD mice. IL-27 receptor was required by both CD4 T effector (Te) cells and CD8 T cells to mediate focal inflammation. Intrinsic IL-27 signaling was associated with PD-1 and ICOS expressing T follicular helper (Tfh)-like CD4 Te cells within lacrimal glands, including subsets defined by CD73 or CD39 expression. CD8 T cells capable of IL-27 signaling also expressed PD-1 with subsets expressing ICOS and CD73 demonstrating a T follicular cytotoxic (Tfc)-like cell phenotype and others expressing a CD39hi exhausted-like phenotype. These findings suggest IL-27 is a key early signal driving a follicular-type response in lacrimal gland inflammation in NOD mice.

A Case of Granulomatosis with Polyangiitis Masquerading as Community Acquired Pneumonia.

Granulomatosis with polyangiitis (GPA) has a multitude of presentations, including appearing as a refractory community-acquired pneumonia (CAP) or an isolated localized pulmonary disease. This case describes a patient suspected to have a CAP before further workup and lung biopsy revealed his diagnosis of GPA. This case report demonstrates GPA's diverse presentations, critical complications such as diffuse alveolar hemorrhage (DAH) and cardiac tamponade, and nuanced management options.

Pediatric rheumatologists' perspectives on diagnosis, treatment, and outcomes of Sjögren disease in children and adolescents.

BACKGROUND: Sjögren disease in children and adolescents (pedSD) presents differently than adult disease. Diagnosis and classification are controversial, optimal treatment is unknown and outcomes are poorly understood. Here, we describe the current perspectives of pediatric rheumatologists on diagnosis, treatment, and outcomes of pedSD. METHODS: A voluntary, 17-question survey was distributed to providers in the Childhood Arthritis and Rheumatology Research Alliance and/or the American College of Rheumatology Childhood Sjögren's Study Group at the 2020 Convergence Virtual Conference. Findings are reported using descriptive statistics and chi-square testing. RESULTS: Of 465 eligible providers, 157 (34%) responded with 135 (29%) completing the survey. The majority (85%) saw five or fewer patients with pedSD in the past year. Parotitis, dry eye and/or dry mouth, and constitutional symptoms were among the most specific and common clinical features. Most providers (77%) used clinical judgment guided by adult criteria for diagnosis. The vast majority (86-99%) of survey participants indicated routine use of serologic testing, while salivary gland ultrasound, minor salivary gland biopsy and other diagnostic tests were less often used. The most commonly prescribed systemic immunomodulators were hydroxychloroquine, corticosteroids, methotrexate, rituximab, and mycophenolate. Seven providers reported malignancy in a patient with pedSD, including one death. CONCLUSIONS: Pediatric rheumatologists diagnose and treat pedSD; however, most only see a few patients per year and rely on clinical judgment and laboratory testing for diagnosis. Treatment frequently includes systemic immunomodulators and malignancies are reported. More studies are needed to better understand natural history, risk factors, and the impact of interventions on outcomes.

Sex differences in comorbidities associated with Sjögren's disease.

Background: Little is known about the association of comorbidities with sex and age at diagnosis in Sjögren's disease. We tested the hypothesis that sex differences occur in comorbidities in patients with Sjögren's disease. Methods: Patients with Sjögren's disease were identified from 11/1974 to 7/2018 in the Mayo Clinic electronic medical record and assessed for 22 comorbidities according to sex and age at diagnosis. Results: Of the 13,849 patients identified with Sjögren's disease, 11,969 (86%) were women and 1,880 (14%) men, primarily white (88%) with a sex ratio of 6.4:1 women to men. The mean age at diagnosis was 57 years for women and 59.7 years for men, and 5.6% had a diagnosis of fibromyalgia at Sjögren's diagnosis. Men with Sjögren's disease were more likely than women to be a current or past smoker. The average time to diagnosis of comorbidities after diagnosis of Sjögren's disease was 2.6 years. The top comorbidities in patients with Sjögren's disease were fibromyalgia (25%), depression (21.2%) and pain (16.4%). Comorbidities that occurred more often in women were hypermobile syndromes (31:1), CREST (29:1), migraine (23:1), Ehlers-Danlos syndrome (EDS) (22:1), Raynaud's syndrome (15:1), SLE (13:1), systemic sclerosis (SSc) (13:1), and fibromyalgia (12:1). Women with Sjögren's disease were at increased risk of developing hypermobile syndromes (RR 7.27, CI 1.00-52.71, p = 0.05), EDS (RR 4.43, CI 1.08-18.14, p = 0.039), CREST (RR 4.24, CI 1.56-11.50, p = 0.005), migraine (RR 3.67, CI 2.39-5.62, p < 0.001), fibromyalgia (RR 2.26, CI 1.92-2.66, p < 0.001), Raynaud's syndrome (RR 2.29, CI 1.77-2.96, p < 0.001), SLE (RR 2.13, CI 1.64-2.76, p < 0.001), and SSc (RR 2.05 CI 1.44-2.92; p < 0.001). In contrast, men with Sjögren's were at increased risk for developing myocardial infarction (RR 0.44, CI 0.35-0.55, p < 0.001), atherosclerosis/CAD (RR 0.44, CI 0.39-0.49, p < 0.001), cardiomyopathy (RR 0.63, CI 0.46-0.86, p = 0.003), stroke (RR 0.66 CI 0.51-0.85, p = 0.001), and congestive heart failure (RR 0.70, CI 0.57-0.85, p < 0.001). Conclusions: The top comorbidities in Sjögren's disease were fibromyalgia, depression, and pain. Women with Sjögren's disease had a higher relative risk of developing fibromyalgia, depression, pain, migraine, hypermobile syndrome, EDS and other rheumatic autoimmune diseases. Men with Sjögren's disease had higher risk of developing cardiovascular diseases.

Recurrent or persistent salivary gland enlargement in children: When is it Sjögren's?

OBJECTIVES: To describe characteristic features in children with recurrent or persistent salivary gland enlargement and to propose a diagnostic algorithm with specific consideration for Sjögren's disease (SD). METHODS: In this single-center, prospective study, 45 patients < 18 years, with recurrent or persistent salivary gland enlargement of unknown etiology were enrolled from 2006 to 2019. We collected detailed clinical information to characterize this group of patients including specific details of their major salivary gland signs and symptoms. We compared clinical, laboratory and radiological parameters between 4 groups based on the results of labial salivary gland biopsy (LSGB) and between patients who met existing SD criteria or not. RESULTS: 44 patients, with a mean age of 6.8 years and female to male ratio 21:23 were observed over a mean of 3.8 years. Characteristics of salivary gland swelling episodes varied considerably between individuals, but the majority experienced ≤5 episodes per year, lasting ≤ 1 week, with swelling affecting either or both glands. Ocular and oral dryness symptoms were observed only in 25% and 59% patients, respectively. The majority were positive for ANA, but negative for SD-specific antibodies. A total of 75% patients fulfilled at least one of the existing SD criteria. CONCLUSION: SD is a major cause of recurrent salivary gland enlargement in children. For children meeting adult criteria, the diagnosis of SD is clear. However, for the many children without dryness symptoms, objective dryness, or SD-specific antibodies, further workup including a combination of salivary gland imaging and histopathological examination can help establish the diagnosis of SD.

Treatment strategies for Sjögren's syndrome with childhood onset: a systematic review of the literature.

OBJECTIVES: SS with childhood onset is a rare autoimmune disease characterized by heterogeneous presentation. The lack of validated classification criteria makes it challenging to diagnose. Evidence-based guidelines for treatment of juvenile SS are not available due to the rarity of disease and the paucity of research in this patient population. This systematic review aims to summarize and appraise the current literature focused on pharmacological strategies for management of SS with childhood onset. METHODS: PubMed and MEDLINE/Scopus databases up to December 2020 were screened for suitable reports highlighting pharmacological treatment of SS with childhood onset using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2009 reporting checklist. Animal studies were excluded. RESULTS: A total of 43 studies (34 case reports, 8 mini case series and 1 pilot study) were eligible for analysis. The studies retrieved included girls in 88% (120/137) of cases and had very low confidence levels. HCQ was prescribed for parotid swelling, as well as in association with MTX and NSAIDs in patients with arthritis and arthralgia. Corticosteroids such as long courses of oral prednisone and i.v. methylprednisolone were commonly prescribed for children with severe disease presentations. Rituximab was mainly indicated for mucosa-associated lymphoid tissue lymphoma and renal and nervous system complications. Other conventional DMARDs were prescribed in selected cases with extraglandular manifestations. CONCLUSION: Various therapies are used for the management of juvenile SS and are prescribed based on expert clinician's opinion. There are currently no good-quality studies that allow clinical recommendations for treatment of SS with childhood onset.

Unique Aspects of Pediatric Sjögren Disease.

Sjögren disease increasingly is recognized in pediatric patients. Clinical features, primarily parotitis and sicca symptoms, and results of diagnostic tests may be different from those in adult disease. Adult criteria fail to capture most pediatric patients. Pediatric-specific criteria are urgently needed to define the natural history of the disease, identify risk and prognostic factors, and evaluate the impact of therapeutics and other interventions on disease course in young patients.

Dataset-chemokines, cytokines, and biomarkers in the saliva of children with Sjögren's syndrome.

Sjögren's syndrome is an autoimmune disease that can also occur in children. The disease is not well defined and there is limited information on the presence of chemokines, cytokines, and biomarkers (CCBMs) in the saliva of children that could improve their disease diagnosis. In a recent study [1], we reported a large dataset of 105 CCBMs that were associated with both lymphocyte and mononuclear cell functions [2] in the saliva of 11 children formally diagnosed with Sjögren's syndrome and 16 normal healthy children. Here, we extend those findings and use the Mendeley dataset [2] to identify CCBMs that have predictive power for Sjögren's syndrome in female children. Datasets of CCBMs from all saliva samples and female children saliva samples were standardized. We used machine learning methods to select Sjögren's syndrome associated CCBMs and assessed the predictive power of selected CCBMs in these two datasets using receiver operating characteristic (ROC) curves and associated areas under curve (AUC) as metrics. We used eight classifiers to identify 16 datasets that contained from 2 to 34 CCBMs with AUC values ranging from 0.91 to 0.94.

Characterization of Type I Interferon-Associated Chemokines and Cytokines in Lacrimal Glands of Nonobese Diabetic Mice.

Type I interferons (IFNs) are required for spontaneous lacrimal gland inflammation in the nonobese diabetic (NOD) mouse model of Sjögren's disease, but the consequences of type I IFN signaling are not well-defined. Here, we use RNA sequencing to define cytokine and chemokine genes upregulated in lacrimal glands of NOD mice in a type I IFN-dependent manner. Interleukin (IL)-21 was the highest differentially expressed cytokine gene, and Il21 knockout NOD mice were relatively protected from lacrimal gland inflammation. We defined a set of chemokines upregulated early in disease including Cxcl9 and Cxcl10, which share a receptor, CXCR3. CXCR3+ T cells were enriched in lacrimal glands with a dominant proportion of CXCR3+ regulatory T cells. Together these data define the early cytokine and chemokine signals associated with type I IFN-signaling in the development of lacrimal gland inflammation in NOD mice providing insight into the role of type I IFN in autoimmunity development.

Clinical and laboratory features of patients with focal lymphocytic sialadenitis on minor salivary gland biopsy for sicca symptoms: A single-center experience.

ABSTRACT: Minor salivary gland biopsy (MSGB) is often used in patients lacking specific autoantibodies (seronegative patients) to confirm the presence of focal lymphocytic sialadenitis (FLS), which would suggest a diagnosis of Sjogren syndrome. There are no current guidelines indicating when to refer patients for MSGB. The objective of our study was to ascertain distinguishing clinical and laboratory features among individuals with sicca symptoms based on their serologic and histopathologic status, and to identify factors associated with FLS.Using a cross-sectional study design, patients ages 18 years or older with sicca symptoms who had MSGB performed at the University of Iowa from January 2000 to December 2016 were selected for chart reviews. The clinical and laboratory features of patients with and without FLS were analyzed using exact univariate and multivariable logistic regression, with Bonferroni correction for multiple comparisons.We identified 177 patients who had MSGB performed and available clinical data. A total of 133 patients had FLS, 37 (27.8%) were seropositive (positive-anti-Sjogren syndrome type A [SSA] and/or anti-Sjogren syndrome type B) and 96 (72.2%) were seronegative. Dry eyes (unadjusted odds ratio [OR]: 5.17, 95% confidence interval [CI]: 1.16-26.30; adjusted odds ratio [aOR]: 12.58, 95% CI: 1.70-167.77) and the presence of anti-SSA (OR: 7.16, 95% CI: 1.70-64.24; aOR: 8.82, 95% CI: 1.73-93.93) were associated with FLS. Smoking (aOR 0.27, 95% CI: 0.11-0.63) and antihistamine use (aOR 0.23, 95% CI: 0.08-0.63) were associated with lower odds of FLS.Our study suggests that dry eyes and anti-SSA positivity are associated with FLS. Smoking and antihistamine use were associated with lower odds of FLS. In the appropriate clinical context, seronegative patients with sicca symptoms and no smoking history could be considered for MSGB. A thorough medication and smoking history should be performed in all patients before referral for MSGB.

Childhood-onset of primary Sjögren's syndrome: phenotypic characterization at diagnosis of 158 children.

OBJECTIVES: To characterize the phenotypic presentation at diagnosis of childhood-onset primary SS. METHODS: The Big Data Sjögren Project Consortium is an international, multicentre registry using worldwide data-sharing cooperative merging of pre-existing clinical SS databases from the five continents. For this study, we selected those patients in whom the disease was diagnosed below the age of 19 years according to the fulfilment of the 2002/2016 classification criteria. RESULTS: Among the 12 083 patients included in the Sjögren Big Data Registry, 158 (1.3%) patients had a childhood-onset diagnosis (136 girls, mean age of 14.2 years): 126 (80%) reported dry mouth, 111 (70%) dry eyes, 52 (33%) parotid enlargement, 118/122 (97%) positive minor salivary gland biopsy and 60/64 (94%) abnormal salivary US study, 140/155 (90%) positive ANA, 138/156 (89%) anti-Ro/La antibodies and 86/142 (68%) positive RF. The systemic EULAR Sjögren's syndrome disease activity index (ESSDAI) domains containing the highest frequencies of active patients included the glandular (47%), articular (26%) and lymphadenopathy (25%) domains. Patients with childhood-onset primary SS showed the highest mean ESSDAI score and the highest frequencies of systemic disease in 5 (constitutional, lymphadenopathy, glandular, cutaneous and haematological) of the 12 ESSDAI domains, and the lowest frequencies in 4 (articular, pulmonary, peripheral nerve and CNS) in comparison with patients with adult-onset disease. CONCLUSIONS: Childhood-onset primary SS involves around 1% of patients with primary SS, with a clinical phenotype dominated by sicca features, parotid enlargement and systemic disease. Age at diagnosis plays a key role in modulating the phenotypic expression of the disease.

A distinguishing profile of chemokines, cytokines and biomarkers in the saliva of children with Sjögren's syndrome.

OBJECTIVE: SS is an autoimmune disease most commonly diagnosed in adults but can occur in children. Our objective was to assess the presence of chemokines, cytokines and biomarkers (CCBMs) in saliva from these children that were associated with lymphocyte and mononuclear cell functions. METHODS: Saliva was collected from 11 children diagnosed with SS prior to age 18 years and 16 normal healthy children. A total of 105 CCBMs were detected in multiplex microparticle-based immunoassays. ANOVA and t test (0.05 level) were used to detect differences. Ingenuity Pathway Analysis (IPA) was used to assess whether elevated CCBMs were in annotations associated with immune system diseases and select leukocyte activities and functions. Machine learning methods were used to evaluate the predictive power of these CCBMs for SS and were measured by receiver operating characteristic (ROC) curve and area under curve (AUC). RESULTS: Of the 105 CCBMs detected, 43 (40.9%) differed in children with SS from those in healthy study controls (P < 0.05) and could differentiate the two groups (P < 0.05). Elevated CCBMs in IPA annotations were associated with autoimmune diseases and with leukocyte chemotaxis, migration, proliferation, and regulation of T cell activation. The best AUC value in ROC analysis was 0.93, indicating that there are small numbers of CCBMs that may be useful for diagnosis of SS. CONCLUSION: While 35 of these 43 CCBMs have been previously reported in SS, 8 CCBMs had not. Additional studies focusing on these CCBMs may provide further insight into disease pathogenesis and may contribute to diagnosis of SS in children.

Childhood Sjögren syndrome: features of an international cohort and application of the 2016 ACR/EULAR classification criteria.

OBJECTIVE: Sjögren syndrome in children is a poorly understood autoimmune disease. We aimed to describe the clinical and diagnostic features of children diagnosed with Sjögren syndrome and explore how the 2016 ACR/EULAR classification criteria apply to this population. METHODS: An international workgroup retrospectively collected cases of Sjögren syndrome diagnosed under 18 years of age from 23 centres across eight nations. We analysed patterns of symptoms, diagnostic workup, and applied the 2016 ACR/EULAR classification criteria. RESULTS: We identified 300 children with Sjögren syndrome. The majority of patients n = 232 (77%) did not meet 2016 ACR/EULAR classification criteria, but n = 110 (37%) did not have sufficient testing done to even possibly achieve the score necessary to meet criteria. Even among those children with all criteria items tested, only 36% met criteria. The most common non-sicca symptoms were arthralgia [n = 161 (54%)] and parotitis [n = 140 (47%)] with parotitis inversely correlating with age. CONCLUSION: Sjögren syndrome in children can present at any age. Recurrent or persistent parotitis and arthralgias are common symptoms that should prompt clinicians to consider the possibility of Sjögren syndrome. The majority of children diagnosed with Sjögren syndromes did not meet 2016 ACR/EULAR classification criteria. Comprehensive diagnostic testing from the 2016 ACR/EULAR criteria are not universally performed. This may lead to under-recognition and emphasizes a need for further research including creation of paediatric-specific classification criteria.

Childhood Sjogren's syndrome: An Italian case series and a literature review-based cohort.

OBJECTIVE: Sjogren's syndrome (SS) is a chronic autoimmune disease with a highly variable presentation. This study aims to describe childhood SS (cSS) features to help guide clinicians in their consideration of and workup for cSS. METHODS: We retrospectively reviewed medical records of patients with cSS referred to three Italian pediatric rheumatology centers from 2015 to 2019 and we conducted a literature review of cSS. Statistical analysis was performed to detect associations between clinical/laboratory features. RESULTS: We reviewed 12 cases (9 female) followed in 3 Italian centers and 240 cases (191 female) in the published literature reporting individual information. The median age at disease onset was 10 years for both cohorts. The most frequently reported clinical SS-specific feature was parotitis in both cohorts (67% each). Extraglandular manifestations were very common and joint involvement was the most frequent. In the cluster analysis, we identified a significant association between parotitis and younger patients (< 11 years). We verified the presence of the main SS features (exocrine gland inflammation, exocrine gland dysfunction, and presence of autoantibodies) in the Italian cohort and the literature review-based cohort: 92% and 80% of the cohorts, respectively, had at least 2/3 main characteristics. CONCLUSION: We described cSS features with relative frequencies and we found that parotid involvement was related to cSS in younger patients. The majority of patients showed various combinations of exocrine gland inflammation, exocrine gland dysfunction, and presence of autoantibodies giving a theoretical basis for future research to pave the way for the development of cSS specific diagnostic criteria.

Toll-Like Receptor 7 Is Required for Lacrimal Gland Autoimmunity and Type 1 Diabetes Development in Male Nonobese Diabetic Mice.

Sjögren syndrome (SS) is an immunologically complex, chronic autoimmune disease targeting lacrimal and salivary glands. Nonobese diabetic (NOD) mice spontaneously develop inflammation of lacrimal and salivary glands with histopathological features similar to SS in humans including focal lymphocytic infiltrates in the affected glands. The innate immune signals driving lymphocytic infiltration of these glands are not well-defined. Here we evaluate the role of Toll-like receptor (TLR) 7 in the development of SS-like manifestations in NOD mice. We created a Tlr7 knockout NOD mouse strain and performed histological and gene expression studies to characterize the effects of TLR7 on autoimmunity development. TLR7 was required for male-specific lacrimal gland inflammation but not for female-specific salivary gland inflammation. Moreover, TLR7 was required for type 1 diabetes development in male but not female NOD mice. RNA sequencing demonstrated that TLR7 was associated with a type I interferon (IFN) response and a type I IFN-independent B cell response in the lacrimal glands. Together these studies identify a previously unappreciated pathogenic role for TLR7 in lacrimal gland autoimmunity and T1D development in male NOD mice adding to the growing body of evidence supporting sex differences in mechanisms of autoimmune disease in NOD mice.

CD226 Deletion Reduces Type 1 Diabetes in the NOD Mouse by Impairing Thymocyte Development and Peripheral T Cell Activation.

The costimulatory molecule CD226 is highly expressed on effector/memory T cells and natural killer cells. Costimulatory signals received by T cells can impact both central and peripheral tolerance mechanisms. Genetic polymorphisms in CD226 have been associated with susceptibility to type 1 diabetes and other autoimmune diseases. We hypothesized that genetic deletion of Cd226 in the non-obese diabetic (NOD) mouse would impact type 1 diabetes incidence by altering T cell activation. CD226 knockout (KO) NOD mice displayed decreased disease incidence and insulitis in comparison to wild-type (WT) controls. Although female CD226 KO mice had similar levels of sialoadenitis as WT controls, male CD226 KO mice showed protection from dacryoadenitis. Moreover, CD226 KO T cells were less capable of adoptively transferring disease compared to WT NOD T cells. Of note, CD226 KO mice demonstrated increased CD8+ single positive (SP) thymocytes, leading to increased numbers of CD8+ T cells in the spleen. Decreased percentages of memory CD8+CD44+CD62L- T cells were observed in the pancreatic lymph nodes of CD226 KO mice. Intriguingly, CD8+ T cells in CD226 KO mice showed decreased islet-specific glucose-6-phosphatase catalytic subunit-related protein (IGRP)-tetramer and CD5 staining, suggesting reduced T cell receptor affinity for this immunodominant antigen. These data support an important role for CD226 in type 1 diabetes development by modulating thymic T cell selection as well as impacting peripheral memory/effector CD8+ T cell activation and function.