This study provides the first evidence of a strong influence of geolocation and ethnicity on the phenotype of primary SjS at diagnosis.

Sjögren’s syndrome is a common autoimmune disease that presents with sicca symptoms and extraglandular features. Sjögren’s syndrome is presumably as common as RA; yet it is poorly understood, underdiagnosed and undertreated. From the usual identity as an autoimmune exocrinopathy to its most recent designate as an autoimmune epithelitis – the journey of SS is complex. We herein review some of the most important milestones that have shed light on different aspects of pathogenesis of this enigmatic disease. This includes role of salivary gland epithelial cells, and their interaction with cells of innate and adaptive immune system. Non-immune factors acting in concert or in parallel with immune factors may also be important. The risk genes identified so far have only weak association, nevertheless advances in genetics have enhanced understanding of disease mechanisms. Role of epigenetic and environmental factors are also being explored. SS also has some unique features such as congenital heart block and high incidence of lymphoma; disease mechanisms accounting for these manifestations are also reviewed.

Objective To characterize the systemic phenotype of primary Sjögren’s syndrome at diagnosis by analysing the EULAR-SS disease activity index (ESSDAI) scores. Methods The Sjögren Big Data Consortium is an international, multicentre registry based on worldwide data-sharing cooperative merging of pre-existing databases from leading centres in clinical research in Sjögren’s syndrome from the five continents. Results The cohort included 10 007 patients (9352 female, mean 53 years) with recorded ESSDAI scores available. At diagnosis, the mean total ESSDAI score was 6.1; 81.8% of patients had systemic activity (ESSDAI score ≥1). Males had a higher mean ESSDAI (8.1 vs 6.0, P < 0.001) compared with females, as did patients diagnosed at <35 years (6.7 vs 5.6 in patients diagnosed at >65 years, P < 0.001). The highest global ESSDAI score was reported in Black/African Americans, followed by White, Asian and Hispanic patients (6.7, 6.5, 5.4 and 4.8, respectively; P < 0.001). The frequency of involvement of each systemic organ also differed between ethnic groups, with Black/African American patients showing the highest frequencies in the lymphadenopathy, articular, peripheral nervous system, CNS and biological domains, White patients in the glandular, cutaneous and muscular domains, Asian patients in the pulmonary, renal and haematological domains and Hispanic patients in the constitutional domain. Systemic activity measured by the ESSDAI, clinical ESSDAI (clinESSDAI) and disease activity states was higher in patients from southern countries (P < 0.001). Conclusion The systemic phenotype of primary Sjögren’s syndrome is strongly influenced by personal determinants such as age, gender, ethnicity and place of residence, which are key geoepidemiological players in driving the expression of systemic disease at diagnosis.

The human body is an environmental niche which is home to diverse co-habiting microbes collectively referred as the human microbiome. Recent years have seen the in-depth characterization of the human microbiome and associations with diseases. Linking of the composition or number of the human microbiota with diseases and traits date back to the original work of Elie Metchnikoff. Recent advances in genomic technologies have opened up finer details and dynamics of this new science with higher precision. Microbe-rheumatoid arthritis connection, largely related to the gut and oral microbiomes, has showed up as a result -apart from several other earlier, well-studied candidate autoimmune diseases. Although evidence favouring roles of specific microbial species, including Porphyromonas, Prevotella and Leptotricha, has become clearer, mechanistic insights still continue to be enigmatic. Manipulating the microbes by traditional dietary modifications, probiotics, and antibiotics and by currently employed disease-modifying agents seems to modulate the disease process and its progression. In the present review, we appraise the existing information as well as the gaps in knowledge in this challenging field. We also discuss the future directions for potential clinical applications, including prevention and management of rheumatoid arthritis using microbial modifications.

Objective : To characterise the clinical features, immunological profile and outcome in a cohort of Asian Indian patients with primary Sjögren's syndrome (SS).Methods : Electronic medical records from a tertiary care teaching hospital in south India were screened for SS between 2004 and 2011. Patients fulfilling American European Consensus group (AECG) 2002 or American College of Rheumatology (ACR) 2012 classification criteria were included. Agglomerative hierarchical cluster analysis to identify patterns of associations between clinical and immunological features was done. Multivariate logistic regression to identify predictors of major systemic involvement was performed. Data on treatment and outcome were retrieved from electronic records.Results : Of 423 patients suspected to have SS, 332 fulfilled inclusion criteria. Only 8.3% of patients complained of sicca symptoms on their own at initial presentation. Younger age of onset, higher female to male ratio, paucity of cryoglobulinemia, Raynaud’s phenomenon and hyperglobulinemia were unique to this cohort. Cluster analysis revealed two subsets: The first cluster comprised of patients having a major systemic illness with high antibody titers and the second comprised of seronegative patients with mild disease. Over a third of SS cases had severe systemic manifestations necessitating treatment with immunosuppressants. In multivariate logistic regression analysis, anti-Ro and anti-La antibody positivity was associated with higher odds for systemic disease features (OR=2.67, P=0.03 and OR=3.25, P=0.003, respectively) whereas chronic pain was associated with lower odds (OR=0.4, p=0.032). Clinical improvement including symptomatic benefit in sicca and musculoskeletal features was noted with immunomodulators in the majority.Conclusion : Our cohort of patients with SS has characteristic clinical features; some of them are in contrast with previous observations reported in European patients. This cohort consisted of two distinct patient clusters. The first cluster was associated with major systemic illness and high antibody titers, where as the second cluster comprised of seronegative patients with mild disease. Association of antibody positivity with systemic features was further confirmed on logistic regression analysis.