Acinar adipose tissue infiltration in salivary gland biopsy is associated with kynurenines-Interferon-γ pathway inflammation biomarkers.

OBJECTIVES: Assess if kynurenines metabolites are biomarkers of damage at labial salivary gland biopsy (LSGB). METHODS: This is a cross-sectional study including 99 patients with primary Sjögren's syndrome (AECG 2002 or ACR/EULAR 2017). Kynurenines were measured in plasma using liquid chromatography-tandem mass spectrometry. RESULTS: 95.9% were females, 51±12 years. Most had focal lymphocytic sialadenitis with focus score ≥1 (73.7%, n=73/99). The majority had mild to severe acinar atrophy (70.4%, n=57/81) and adipose infiltration (51.2%, n=39/80). Individuals with adipose infiltration were older (53.49±12.33 vs. 47.51±11.29 years, p=0.016), showed higher frequency of glandular dysfunction and higher kynurenines levels. Schirmer's test ≤ 5 mm/5min was found in 69.2% of individuals with adipose infiltration compared to 41% without (p=0.012) and unstimulated whole salivary flow (UWSF) was found in 87.2% compared to 70% without adipose infiltration (p=0.063). Additionally, individuals with adipose infiltration showed higher kynurenines metabolites compared with those without: quinolinic acid (503.35±193.30 vs. 427.35±285.76 nmol/L, p=0.029), kynurenine (1.99±0.6, 54 vs. 1.61±0.46 µmol/L, p=0.006), kynurenine/tryptophan ratio (KTR) (0.030±0.09 vs. 0.025±0.01, p=0.031) and anthranilic acid (03±4.96 vs. 16.46±5.24 nmol/L, p=0.022). CONCLUSIONS: Kynurenines are biomarkers of greater adipose infiltration in LSGB and glandular dysfunction suggesting that activation of interferon-γ pathway is involved in the salivary and lacrimal glands damage.

Identification of a Sjögren's syndrome susceptibility locus at OAS1 that influences isoform switching, protein expression, and responsiveness to type I interferons.

Sjögren's syndrome (SS) is a common, autoimmune exocrinopathy distinguished by keratoconjunctivitis sicca and xerostomia. Patients frequently develop serious complications including lymphoma, pulmonary dysfunction, neuropathy, vasculitis, and debilitating fatigue. Dysregulation of type I interferon (IFN) pathway is a prominent feature of SS and is correlated with increased autoantibody titers and disease severity. To identify genetic determinants of IFN pathway dysregulation in SS, we performed cis-expression quantitative trait locus (eQTL) analyses focusing on differentially expressed type I IFN-inducible transcripts identified through a transcriptome profiling study. Multiple cis-eQTLs were associated with transcript levels of 2'-5'-oligoadenylate synthetase 1 (OAS1) peaking at rs10774671 (PeQTL = 6.05 × 10-14). Association of rs10774671 with SS susceptibility was identified and confirmed through meta-analysis of two independent cohorts (Pmeta = 2.59 × 10-9; odds ratio = 0.75; 95% confidence interval = 0.66-0.86). The risk allele of rs10774671 shifts splicing of OAS1 from production of the p46 isoform to multiple alternative transcripts, including p42, p48, and p44. We found that the isoforms were differentially expressed within each genotype in controls and patients with and without autoantibodies. Furthermore, our results showed that the three alternatively spliced isoforms lacked translational response to type I IFN stimulation. The p48 and p44 isoforms also had impaired protein expression governed by the 3' end of the transcripts. The SS risk allele of rs10774671 has been shown by others to be associated with reduced OAS1 enzymatic activity and ability to clear viral infections, as well as reduced responsiveness to IFN treatment. Our results establish OAS1 as a risk locus for SS and support a potential role for defective viral clearance due to altered IFN response as a genetic pathophysiological basis of this complex autoimmune disease.

Aberrant cell signalling in PBMCs upon IFN-α stimulation in primary Sjögren's syndrome patients associates with type I interferon signature.

Primary Sjögren's syndrome (pSS) is a complex systemic autoimmune disease with heterogeneous disease manifestations. Genetic predisposition, hormonal and environmental factors are all thought to contribute to disease etiology and pathogenesis. A better understanding of the disease pathogenesis is required in order to establish new targeted therapies. We analysed MAPK/ERK and JAK/STAT signalling networks in peripheral blood mononuclear cells (PBMCs) upon stimulation with interferon alpha 2b (IFN-α2b) by flow cytometry to define potentially dysfunctional intracellular signalling pathways involved in disease pathogenesis. Cells derived from pSS patients displayed small but significant increases in basal phosphorylation levels of numerous signalling proteins compared to cells from healthy donors. The phosphorylation profiles following stimulation with IFNα2b differed significantly between pSS patients and healthy donors, especially regarding STAT1 Y701. PCA further grouped patients according to clinical characteristics. Type I IFN induced gene expression was found to negatively correlate with the IFN-α2b induced phosphorylation of STAT3 S727 in T cells and positively with pSTAT1 Y701 in B cells. Increases in pSTAT1 Y701 were associated with the presence of autoantibodies. Our results indicate involvement of both STAT3 S727 and STAT1 Y701 pathways in pSS patients. Therapies targeting these pathways might therefore be beneficial for certain subgroups of patients.

Assessment of major salivary gland ultrasonography in Sjögren's syndrome. A comparison between bedside and post-examination evaluations.

OBJECTIVES: Major salivary gland ultrasonography (SGUS) is a suitable diagnostic tool in Sjögren's syndrome (SS). We aimed to determine the more representative gland, projection and format most applicable for reproducible image analysis. METHODS: One investigator performed SGUS in patients with SS. Parotid and submandibular glands were examined in longitudinal and transverse planes and evaluated bedside using a simplified scoring system (0-3). Longitudinal and transverse images and videos of all glands were stored and later evaluated/graded by three investigators, at two time-points. Agreement was calculated using intraclass correlation coefficient (ICC). RESULTS: The ICC for static image and video scoring compared to bedside evaluation ranged from 0.131 to 0.882. Average ICC for longitudinal/transverse image was 0.667/0.662, and 0.683/0.510 for longitudinal/transverse video. Interobserver reliability was good to excellent (0.81-0.94). Intraobserver reliability scores ranged from fair to excellent (0.46-0.96). The correlation between image and video evaluations of all modalities and examiners was good to excellent (0.614-0.904). The best mean ICC was found for the longitudinal projection of the left parotid gland (0.861) and the lowest mean ICC was for the transverse projection of the left submandibular gland (0.66). CONCLUSIONS: Our study indicates a trend favouring longitudinal video of the parotid gland as preferred projection, gland and storage format.

T follicular-like helper cells in the peripheral blood of patients with primary Sjögren's syndrome.

Primary Sjögren's syndrome (pSS) is a chronic autoimmune disease characterized by exocrine gland dysfunction, mainly causing sicca symptoms. B cells have a prominent role in SS, and the T follicular helper (TFH ) cells provide B cells with survival- and specialization signals in germinal centers. Here we investigate peripheral TFH cells in pSS. Sixteen pSS patients and healthy controls were enrolled in the study, with thirteen women and three men in each group. Whole blood was collected and separated into PBMC and plasma, followed by cryopreservation. Plasma samples were analyzed for Ro52, Ro60 and La48 autoantibodies by indirect ELISA. For flow cytometric analysis, we defined four subsets of TFH-like cells within the CD3+CD4+CXCR5+ population, namely the ICOS-PD1-, ICOS-PD-1+, ICOS+PD-1- and ICOS+PD-1+ ("TFH") cells. We also investigated four CD19+ B cell subsets, the CD20+CD27+CD38- memory B cells, CD20+CD27+CD38+ memory B cells, CD20-CD27+CD38++CD138- plasmablasts and CD20-CD27+CD38++CD138+ plasma cells. We observed higher fractions of ICOS+PD-1- cells, ICOS+PD-1+ ("TFH ") cells and plasmablasts in pSS patients compared to controls, and lower frequencies of both types of memory B cells. The number of TFH cells correlated positively with the levels of plasmablasts and plasma cells in the pSS patients, but not in the controls. The pSS patients were stratified according to Ro52/Ro60/La48 serology, and a positive association was found between autoantibody levels and increased level of TFH cells, plasmablasts and plasma cells and lowered levels of memory B cells. We observed a higher response to Ro/La stimulation in pSS patients compared to controls of the memory B cells, although only significantly for the CD38- memory B cells. Overall, a pathological relation between the ICOS+ T follicular-like helper cells and B cells in pSS was observed, but further work should be conducted to explore their overall impact upon disease progression. This article is protected by copyright. All rights reserved.

The IRF5-TNPO3 association with systemic lupus erythematosus has two components that other autoimmune disorders variably share.

Exploiting genotyping, DNA sequencing, imputation and trans-ancestral mapping, we used Bayesian and frequentist approaches to model the IRF5-TNPO3 locus association, now implicated in two immunotherapies and seven autoimmune diseases. Specifically, in systemic lupus erythematosus (SLE), we resolved separate associations in the IRF5 promoter (all ancestries) and with an extended European haplotype. We captured 3230 IRF5-TNPO3 high-quality, common variants across 5 ethnicities in 8395 SLE cases and 7367 controls. The genetic effect from the IRF5 promoter can be explained by any one of four variants in 5.7 kb (P-valuemeta = 6 × 10(-49); OR = 1.38-1.97). The second genetic effect spanned an 85.5-kb, 24-variant haplotype that included the genes IRF5 and TNPO3 (P-valuesEU = 10(-27)-10(-32), OR = 1.7-1.81). Many variants at the IRF5 locus with previously assigned biological function are not members of either final credible set of potential causal variants identified herein. In addition to the known biologically functional variants, we demonstrated that the risk allele of rs4728142, a variant in the promoter among the lowest frequentist probability and highest Bayesian posterior probability, was correlated with IRF5 expression and differentially binds the transcription factor ZBTB3. Our analytical strategy provides a novel framework for future studies aimed at dissecting etiological genetic effects. Finally, both SLE elements of the statistical model appear to operate in Sjögren's syndrome and systemic sclerosis whereas only the IRF5-TNPO3 gene-spanning haplotype is associated with primary biliary cirrhosis, demonstrating the nuance of similarity and difference in autoimmune disease risk mechanisms at IRF5-TNPO3.

Influence of geolocation and ethnicity on the phenotypic expression of primary Sjögren's syndrome at diagnosis in 8310 patients: a cross-sectional study from the Big Data Sjögren Project Consortium.

OBJECTIVES: To analyse the influence of geolocation and ethnicity on the clinical presentation of primary Sjögren's syndrome (SjS) at diagnosis. METHODS: The Big Data Sjögren Project Consortium is an international, multicentre registry designed in 2014. By January 2016, 20 centres from five continents were participating. Multivariable logistic regression analyses were performed. RESULTS: We included 7748 women (93%) and 562 men (7%), with a mean age at diagnosis of primary SjS of 53 years. Ethnicity data were available for 7884 patients (95%): 6174 patients (78%) were white, 1066 patients (14%) were Asian, 393 patients (5%) were Hispanic, 104 patients (1%) were black/African-American and 147 patients (2%) were of other ethnicities. SjS was diagnosed a mean of 7 years earlier in black/African-American compared with white patients; the female-to-male ratio was highest in Asian patients (27:1) and lowest in black/African-American patients (7:1); the prevalence of sicca symptoms was lowest in Asian patients; a higher frequency of positive salivary biopsy was found in Hispanic and white patients. A north-south gradient was found with respect to a lower frequency of ocular involvement in northern countries for dry eyes and abnormal ocular tests in Europe (OR 0.46 and 0.44, respectively) and Asia (OR 0.18 and 0.49, respectively) compared with southern countries. Higher frequencies of antinuclear antibodies (ANAs) were reported in northern countries in America (OR=1.48) and Asia (OR=3.80) while, in Europe, northern countries had lowest frequencies of ANAs (OR=0.67) and Ro/La (OR=0.69). CONCLUSIONS: This study provides the first evidence of a strong influence of geolocation and ethnicity on the phenotype of primary SjS at diagnosis.

Defining disease activity states and clinically meaningful improvement in primary Sjögren's syndrome with EULAR primary Sjögren's syndrome disease activity (ESSDAI) and patient-reported indexes (ESSPRI).

OBJECTIVES: To define disease activity levels, minimal clinically important improvement (MCII) and patient-acceptable symptom state (PASS) with the primary Sjögren's syndrome (SS) disease activity indexes: European League Against Rheumatism (EULAR) SS disease activity index (ESSDAI) and EULAR SS patient-reported index (ESSPRI). METHODS: For 790 patients from two large prospective cohorts, ESSDAI, physician evaluation of disease activity, ESSPRI and patients' satisfaction with their current health status were recorded. Receiver operating characteristic curve analyses and anchoring methods were used to estimate disease activity levels of ESSDAI and the PASS of ESSPRI. At follow-up visit, patients and physicians assessed, respectively, whether symptoms and disease activity have improved or not. An anchoring method based on this evaluation was used to estimate MCII of ESSDAI and ESSPRI. RESULTS: Low-activity (ESSDAI<5), moderate-activity (5≤ESSDAI≤13) and high-activity (ESSDAI≥14) levels were defined. MCII of ESSDAI was defined as an improvement of at least three points. The PASS estimate was defined as an ESSPRI<5 points and MCII as a decrease of at least one point or 15%. CONCLUSIONS: This study determined disease activity levels, PASS and MCII of ESSDAI and ESSPRI. These results will help designing future clinical trials in SS. For evaluating systemic complications, the proposal is to include patients with moderate activity (ESSDAI≥5) and define response to treatment as an improvement of ESSDAI at least three points. For addressing patient-reported outcomes, inclusion of patients with unsatisfactory symptom state (ESSPRI≥5) and defining response as an improvement of ESSPRI at least one point or 15% seems reasonable.

Sjögren's syndrome patients with ectopic germinal centers present with a distinct salivary proteome.

OBJECTIVE: Clinical expression of SS shows considerable interpatient heterogeneity. Thus, the aim of this study was to assess whether individual salivary proteomic profiles provide a framework for identification of disease-phenotype-driven biomarker signatures. METHODS: Using a 187-plex capture antibody-based assay, proteomic biomarker profiles from unstimulated whole saliva were generated from a SS-cohort representing six clinically distinct disease phenotypes. Discriminant function analyses identified the most powerful biomarker signatures for correct recapitulation of each patient's status with respect to hyposalivation and histopathological features of salivary gland inflammation. In addition, gene ontology-based network analyses allowed systematic interpretation of the molecular patterns underlying these specific disease features. RESULTS: Presentation of hyposalivation was associated with significant alteration in 22 out of 119 reliably detectable biomarkers. Thereof, a 4-plex signature allowed accurate prediction of salivary gland function for >80% of the cases. With respect to histopathological features, the most distinct profiles were identified in conjunction with ectopic germinal centres. Selected from the 13 analytes relevant here, pregnancy-associated plasma protein A, thrombospondin 1 and peptide YY would recapitulate the presence or absence of tertiary lymphoid organization for 93.8% of the patients. Whereas functional annotation of alterations associated with hyposalivation identified the IL1 system as a dominant pro-inflammatory component, changes observed in context with ectopic lymphoid organization revealed specific shifts in chemotactic profiles and altered regulation of apoptotic processes. CONCLUSION: Multivariate analyses of a patient's salivary proteome could reliably recapitulate specific aspects of SS disease. Accessible and repetitively collectable, such biomarker signatures harbour great potential for patient subclassification and subsequent follow-up.

Atherosclerosis in Sjögren's syndrome: evidence, possible mechanisms and knowledge gaps.

Inflammation has been associated with higher cardiovascular risk in rheumatic autoimmune diseases like rheumatoid arthritis (RA) and systemic lupus erythematosus. More recently, primary Sjögren's syndrome (pSS) was also demonstrated as an independent risk factor for cardiovascular disease, emerging as a new interesting model to study atherosclerosis in autoimmune diseases. Patients with pSS have a higher prevalence of developing traditional cardiovascular risk factors like hypertension and dyslipidaemia predisposing for endothelial dysfunction and premature atherosclerosis. However, the disease-specific mechanisms for premature atherosclerosis in pSS are not fully understood. The aim of this review was to critically analyse the current literature on cardiovascular risks in pSS and to discuss the traditional and disease-associated risk factors. We also suggest possible new mechanisms that should be explored in future research to close the current knowledge gaps on the association of pSS, premature atherosclerosis, and clinical cardiovascular disease.

Serum calprotectin is a biomarker of carotid atherosclerosis in patients with primary Sjögren's syndrome.

OBJECTIVES: We aimed to identify the association of carotid atherosclerosis with the traditional risk factors, disease features, cytokine profile, and calprotectin in patients with primary Sjögren's syndrome (pSS). METHODS: 63 primary pSS patients and 63 age- and sex-matched healthy controls underwent carotid ultrasound, clinical and laboratory examination. The presence of carotid plaques was taken as carotid atherosclerosis. The covariates of carotid atherosclerosis were identified in univariate and multivariate regressions. RESULTS: Patients with pSS had higher prevalence of carotid atherosclerosis (13% vs. 2%, p<0.05) and higher serum levels of calprotectin, tumour necrosis factor receptor 2 (TNF-R2), hepatocyte growth factor (HGF), and monocyte chemoattractant protein-1 (MCP-1) than controls. Sex, menopause, and the prevalence of traditional cardiovascular did not differ between groups (all p>0.05). In univariate analyses, serum calprotectin, most traditional cardiovascular (age, male sex, metabolic syndrome, hypertension, hypertriglyceridaemia, and serum creatinine), and some disease-associated risk factors (glucocorticoid or saliva substitute use, constitutional domain of Eular-Sjögren's syndrome disease activity index - EULAR) were associated with a higher risk for plaque. In a multivariate analysis, having pSS and higher serum calprotectin were associated with carotid atherosclerosis independent of traditional risk factors. CONCLUSIONS: pSS have a higher prevalence of carotid atherosclerosis, which is associated with higher serum calprotectin level independent of traditional cardiovascular risk factors. Our findings suggest calprotectin as a biomarker of subclinical atherosclerosis in pSS.

Carbamylation of immunoglobulin abrogates activation of the classical complement pathway.

Post-translational modifications of proteins significantly affect their structure and function. The carbamylation of positively charged lysine residues to form neutral homoitrulline occurs primarily under inflammatory conditions through myeloperoxidase-dependent cyanate (CNO-) formation. We analyzed the pattern of human IgG1 carbamylation under inflammatory conditions and the effects that this modification has on the ability of antibodies to trigger complement activation via the classical pathway. We found that the lysine residues of IgG1 are rapidly modified after brief exposure to CNO- . Interestingly, modifications were not random, but instead limited to only few lysines within the hinge area and the N-terminal fragment of the CH2 domain. A complement activation assay combined with mass spectrometry analysis revealed a highly significant inverse correlation between carbamylation of several key lysine residues within the hinge region and N-terminus of the CH2 domain and the proper binding of C1q to human IgG1 followed by subsequent complement activation. This severely hindered complement-dependent cytotoxicity of therapeutic IgG1 . The reaction can apparently occur in vivo, as we found carbamylated antibodies in synovial fluid from rheumatoid arthritis patients. Taken together, our data suggest that carbamylation has a profound impact on the complement-activating ability of IgG1 and reveals a pivotal role for previously uncharacterized lysine residues in this process.

Validation of EULAR primary Sjögren's syndrome disease activity (ESSDAI) and patient indexes (ESSPRI).

OBJECTIVES: To validate the two recently developed disease activity indexes for assessment of primary Sjögren's syndrome (SS): the European League Against Rheumatism (EULAR) SS Patient Reported Index (ESSPRI) and the EULAR SS Disease Activity Index (ESSDAI). METHODS: A prospective international 6-month duration validation study was conducted in 15 countries. At each visit, physicians completed ESSDAI, SS disease activity index (SSDAI), Sjögren's Systemic Clinical Activity Index (SCAI) and physician global assessment (PhGA); and patients completed ESSPRI, Sicca Symptoms Inventory (SSI), Profile of Fatigue and Discomfort (PROFAD) and patient global assessment (PGA). Psychometric properties (construct validity, responsiveness and reliability) were evaluated and compared between scores. RESULTS: Of the 395 patients included, 145 (37%) and 251 (64%) had currently active or current or past systemic manifestations, respectively. EULAR scores had higher correlation with the gold standard than other scores (ESSDAI with PhGA: r=0.59; ESSRPI with PGA: r=0.70). Correlations between patient and systemic scores were very low (ranging from 0.07 to 0.29). All systemic scores had similar large responsiveness in improved patients. Responsiveness of patient scores was low but was significantly higher for ESSPRI compared with SSI and PROFAD. Reliability was very good for all scores. CONCLUSIONS: ESSDAI and ESSPRI had good construct validity. All scores were reliable. Systemic scores had a large sensitivity to change in patients whose disease activity improves. Patient scores had a small sensitivity to change, however, significantly better for ESSPRI. Systemic and patient scores poorly correlated, suggesting that they are 2 complementary components that should be both evaluated, but separately.

Diagnostic utility of major salivary gland ultrasonography in primary Sjögren's syndrome.

OBJECTIVES: To investigate major salivary gland ultrasonography (US) in relation to symptoms and findings of oral and ocular dryness, and autoimmune disease, for potential use in diagnosis and follow-up of patients with primary Sjögren's syndrome (pSS). METHODS: Patients with pSS were recruited from the Department of Rheumatology, Haukeland University Hospital. The parotid and submandibular salivary glands were examined by US using a simplified scoring system for glandular homogeneity and hypoechogenic areas. Scans were graded on a scale 0-3, grades 0-1 considered corresponding to normal/non-specific changes and grades 2-3 to pathological changes. Sicca symptoms of the mouth and eyes, salivary gland capacity, tear secretion, minor salivary gland inflammation, serum autoantibodies, and fatigue were also investigated. RESULTS: US was performed in 97 patients. Oral and ocular sicca symptoms correlated with US score and decreased saliva levels. Fatigue VAS correlated with oral sicca symptoms but was inversely correlated with age. Patients with normal/non-specific US findings tended to be older than patients with pathological US findings. US score correlated with unstimulated and stimulated salivary secretion and tear secretion. Minor salivary gland inflammation correlated with major salivary gland US findings, and lymphoid organisation, germinal centre (GC)-like structures, in the minor salivary gland tissue biopsies was seemingly related to US pathology. Serum autoantibodies against Ro/SSA and/or La/SSB were associated with US pathology. CONCLUSIONS: US findings in major salivary glands correlate with subjective and objective oral and ocular items as well as systemic autoimmune features of pSS. US represents a useful imaging tool for diagnostics and follow-up of pSS.

Genetic associations to germinal centre formation in primary Sjogren's syndrome.

BACKGROUND: Primary Sjögren's syndrome (pSS) is an autoimmune rheumatic disease mainly characterised by focal mononuclear cell infiltration in the salivary and lacrimal glands, and by the symptoms xerostomia and keratoconjunctivitis sicca. Germinal centre-like structures (GC) are found in the minor salivary glands of approximately 25% of patients. In this study, we aimed to assess genetic variations in pSS patients with GC-like formations (GC+) compared with patients without such formations (GC-). METHODS: Minor salivary gland biopsies from Swedish and Norwegian pSS patients (n=320) were evaluated for GC-like formations, identifying 76 GC+ and 244 GC- patients. A panel of 1536 single-nucleotide polymorphisms (SNPs) in 107 genes was genotyped. Minor allele frequencies in GC+ and GC- patients were compared using Fisher's exact test, and associations were considered significant when p<4.7×10(-4) and suggestive when p<0.01. RESULTS: In this case-only analysis, we identified two SNPs in CCL11 (eotaxin) associated with GC-like structures (p<4.7×10(-4), OR 0.45 and 0.41, respectively). A haplotype of the two minor alleles was associated with GC status with p=2.6×10(-4), OR 0.40. Suggestive associations (p<0.01) were found in SNPs in the B cell activation and/or GC-formation related genes AICDA, BANK1 and BCL2. Furthermore, SNPs in IL17A, ICA1, PKN1 and SNPs in the NF-κB pathway genes CARD8, IKBKE and TANK were found suggestively associated with GC-like structures. CONCLUSIONS: Our findings suggest that genetic variations may explain why ectopic GC-like structures are present in some pSS patients, and support the hypothesis that GC+ and GC- patients represent distinct disease phenotypes.

A possible genetic association with chronic fatigue in primary Sjögren's syndrome: a candidate gene study.

Fatigue is prevalent and disabling in primary Sjögren's syndrome (pSS). Results from studies in chronic fatigue syndrome (CFS) indicate that genetic variation may influence fatigue. The aim of this study was to investigate single nucleotide polymorphism (SNP) variations in pSS patients with high and low fatigue. A panel of 85 SNPs in 12 genes was selected based on previous studies in CFS. A total of 207 pSS patients and 376 healthy controls were genotyped. One-hundred and ninety-three patients and 70 SNPs in 11 genes were available for analysis after quality control. Patients were dichotomized based on fatigue visual analogue scale (VAS) scores, with VAS <50 denominated "low fatigue" (n = 53) and VAS ≥50 denominated "high fatigue" (n = 140). We detected signals of association with pSS for one SNP in SLC25A40 (unadjusted p = 0.007) and two SNPs in PKN1 (both p = 0.03) in our pSS case versus control analysis. The association with SLC25A40 was stronger when only pSS high fatigue patients were analysed versus controls (p = 0.002). One SNP in PKN1 displayed an association in the case-only analysis of pSS high fatigue versus pSS low fatigue (p = 0.005). This candidate gene study in pSS did reveal a trend for associations between genetic variation in candidate genes and fatigue. The results will need to be replicated. More research on genetic associations with fatigue is warranted, and future trials should include larger cohorts and multicentre collaborations with sharing of genetic material to increase the statistical power.

The neutrophil protein S100A12 is associated with a comprehensive ultrasonographic synovitis score in a longitudinal study of patients with rheumatoid arthritis treated with adalimumab.

BACKGROUND: The calcium-binding protein S100A12 correlates with measures of disease activity in patients with rheumatoid arthritis (RA). The protein reflects neutrophil activation and the present objective was to explore in a pilot study the associations between S100A12 and other inflammatory markers, clinical assessments as well as degree of synovitis detected by a comprehensive ultrasonography (US) examination in RA patients during biologic treatment. METHODS: Twenty patients with RA were examined clinically and by use of US as well as laboratory markers S100A12, calprotectin, C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) before starting adalimumab, with follow-up after 1, 3, 6 and 12 months. Ultrasonographic B-mode (BM) and power Doppler (PD) assessments of 78 joints, 36 tendons/tendon groups and 2 bursas were performed, and sum US scores calculated. Wilcoxon signed rank test assessed treatment response and Spearman rank correlation test was used to calculate correlations. RESULTS: The concentrations of S100A12 decreased after 3 months (p < 0.01) and significant correlations were found between S100A12 and the other laboratory markers during follow-up (0.50-0.62, p < 0.05). Of the clinical assessments, S100A12 had highest correlations with the assessor's global VAS (0.46-0.85, p < 0.05). Compared with CRP and ESR, S100A12 showed higher correlations with the sum US scores (both BM and PD), with median (range) correlation coefficients of 0.55 (0.35-0.78 (NS-p < 0.001)) for sum BM scores and 0.45 (0.27-0.75 (NS-p < 0.001)) for sum PD scores. CONCLUSIONS: The S100A12 protein was significantly associated with other inflammatory markers, clinical assessments as well as sum US scores, indicating that S100A12 is a potential marker of inflammation in RA patients.

Association of genes in the NF-κB pathway with antibody-positive primary Sjögren's syndrome.

Primary Sjögren's syndrome (SS) is a systemic autoimmune inflammatory disease characterized by focal lymphocytic infiltrates in the lachrymal and salivary glands and autoantibodies against the SSA/Ro and SSB/La antigens. Experimental studies have shown an activation of NF-κB in primary SS. NF-κB activation results in inflammation and autoimmunity and is regulated by inhibitory and activating proteins. Genetic studies have shown an association between multiple autoimmune diseases and TNFAIP3 (A20) and TNIP1 (ABIN1), both repressors of NF-κB and of IKBKE (IKKε), which is an NF-κB activator. The aim of this study was to analyse single nucleotide polymorphisms (SNPs) in the IKBKE, NFKB1, TNIP1 and TNFAIP3 genes for association with primary SS. A total of 12 SNPs were genotyped in 1105 patients from Scandinavia (Sweden and Norway, n = 684) and the UK (n = 421) and 4460 controls (Scandinavia, n = 1662, UK, n = 2798). When patients were stratified for the presence of anti-SSA and/or anti-SSB antibodies (n = 868), case-control meta-analysis found an association between antibody-positive primary SS and two SNPs in TNIP1 (P = 3.4 × 10(-5) , OR = 1.33, 95%CI: 1.16-1.52 for rs3792783 and P = 1.3 × 10(-3) , OR = 1.21, 95%CI: 1.08-1.36 for rs7708392). A TNIP1 risk haplotype was associated with antibody-positive primary SS (P = 5.7 × 10(-3) , OR = 1.47, 95%CI: 1.12-1.92). There were no significant associations with IKBKE, NFKB1 or TNFAIP3 in the meta-analysis of the Scandinavian and UK cohorts. We conclude that polymorphisms in TNIP1 are associated with antibody-positive primary SS.

Association between genetic variants in the tumour necrosis factor/lymphotoxin α/lymphotoxin ß locus and primary Sjogren's syndrome in Scandinavian samples.

OBJECTIVES: Lymphotoxin ß (LTB) has been found to be upregulated in salivary glands of patients with primary Sjögren's syndrome (pSS). An animal model of pSS also showed ablation of the lymphoid organisation and a marked improvement in salivary gland function on blocking the LTB receptor pathway. This study aimed to investigate whether single-nucleotide polymorphisms (SNP) in the lymphotoxin α (LTA)/LTB/tumour necrosis factor (TNF) gene clusters are associated with pSS. METHODS: 527 pSS patients and 532 controls participated in the study, all of Caucasian origin from Sweden and Norway. 14 SNP markers were genotyped and after quality control filtering, 12 SNP were analysed for their association with pSS using single marker and haplotype tests, and corrected by permutation testing. RESULTS: Nine markers showed significant association with pSS at the p=0.05 level. Markers rs1800629 and rs909253 showed the strongest genotype association (p=1.64E-11 and p=4.42E-08, respectively, after correcting for sex and country of origin). When the analysis was conditioned for the effect of rs1800629, only the association with rs909253 remained nominally significant (p=0.027). In haplotype analyses the strongest effect was observed for the haplotype rs909253G_rs1800629A (p=9.14E-17). The associations were mainly due to anti-Ro/SSA and anti-La/SSB antibody-positive pSS. CONCLUSIONS: A strong association was found between several SNP in the LTA/LTB/TNFα locus and pSS, some of which led to amino acid changes. These data suggest a role for this locus in the development of pSS. Further studies are needed to examine if the genetic effect described here is independent of the known genetic association between HLA and pSS.

Large molecular size EDTA-resistant complexes containing S100A12, ERAC, in serum during inflammatory conditions.

The pro-inflammatory, leukocyte-derived S100A12 protein occurs as calcium-dependent oligomers in serum, while EDTA plasma from the majority of healthy individuals contains only monomers. Addition of 5 mM EDTA to serum leads to a rapid dissociation of the oligomers in most samples. However, using gel permeation chromatography, we have found that sera from some patients and seemingly healthy individuals contain molecular complexes in the 400-1000 kDa range reacting with anti-S100A12 even in the presence of EDTA; for these we introduce the name ERAC (EDTA Resistant S100A12 Complexes). Based upon monoclonal antibodies and the lateral flow principle, we have developed a quantitative rapid ERAC test giving results within 10 minutes. The highest prevalence of ERAC positivity was found in sera from patients with concomitant rheumatoid arthritis and coronary heart disease. The structure of ERAC is not yet known. Further studies are needed to analyse the mechanism behind the appearance of ERAC and the possible association with inflammatory-related diseases.