Sjögren's syndrome: Infections that may play a role in pathogenesis, mimic the disease, or complicate the patient's course

Respiratory infection risk in primary Sjögren's syndrome complicated with interstitial lung disease: a retrospective study

OBJECTIVES

To explore clinical and laboratory characteristics of primary Sjögren's syndrome (pSS) complicated with interstitial lung disease (ILD) and investigate the risk factors for respiratory infections in pSS-ILD.

METHODS

A cohort of 162 pSS-ILD patients in Peking University People's Hospital from 2015 to 2020 were included, and all medical records were completely collected. We screened 53 patients suffering from respiratory infections as study cases, compared with 109 age- and sex-matched controls. Differences between infection group and control group were compared. Univariate and multivariate binary logistic regression tests were conducted to identify potential risk factors for respiratory infections in pSS-ILD patients.

RESULTS

Among 162 pSS-ILD patients, 32.72% (53/162) suffered from respiratory infections. The most frequent type of ILD was nonspecific interstitial pneumonia (32.08%, 51/159), and the most common type of pathogen was bacteria (64.25%, 34/53). Infection group showed higher levels of ESSDAI (P < 0.001), CRP (P < 0.001), ESR (P = 0.003), and C3 (P = 0.020) but lower level of DLCO-SB (P = 0.015). Univariate logistic model revealed that PAH and the use of glucocorticoid increased infection risk in pSS-ILD patients. On multivariate logistic regression analysis, PAH (OR = 3.993, 95% CI = 1.192-13.373, P = 0.025) and severe reduction of DLCO (DLCO-SB < 40%, OR = 4.625, 95% CI = 1.281-16.702, P = 0.019) were significantly associated with increased risk of respiratory infections in pSS-ILD patients.

CONCLUSION

Among pSS-ILD patients, the most frequent type of ILD was nonspecific interstitial pneumonia. In patients with infection, bacteria were the most common pathogen. Higher levels of ESSDAI, CRP, ESR, and C3 may be correlated with increased infection risk. PAH and reduction of DLCO were identified as independent risk factors. Key Points • ILD and infectious diseases severely affect pSS patient conditions. • Higher levels of ESSDAI, CRP, ESR, and C3 may be correlated with increased infection risks in pSS-ILD. • PAH and reduction of DLCO were identified as independent risk factors for lower respiratory infection.

Risk of primary Sjogren's Syndrome following human papillomavirus infections: a nationwide population-based cohort study

Introduction

Viral infection is an exogeneous factor for primary Sjogren's syndrome (pSS). This study investigated the association between human papillomavirus (HPV) infections and pSS through a nationwide population based cohort study.

Methods

Patients with HPV infections between January, 1999 and December, 2013 were included. The incidence of new-onset pSS in patients with HPV infections and non-HPV controls were derived. The multiple Cox regression model derived the risk of pSS in patients with HPV infections. Subgroup analysis and sensitivity analysis were performed to validate the association.

Results

During a follow-up period of 12 years, the adjusted hazard ratio (aHR) of pSS in patients with HPV infections was significantly higher than that in non-HPV controls (aHR=1.64, 95% CI=1.47-1.83, P<0.001). The risk of pSS increased with age and the risk increased by 2.64-fold (95% CI= 2.37-2.93) for those older than 45 years. The significant association between HPV infections and the risk of pSS persisted in the sensitivity analysis restricted in HPV infections that lasted over 12 months (aHR=1.63, 95%CI=1.45-1.83, P<0.0001). Subgroup analyses revealed that both male (aHR=1.83, 95%CI=1.47-2.28, P<0.0001) and female (aHR=1.58, 95%CI=1.40-1.79, P<0.0001) patients with HPV infections and HPV-infected patients aged between 16 and 45 years (aHR=1.60, 95%CI=1.34-1.91, P<0.0001) and over 45 years (aHR=1.67, 95%CI=1.46-1.91, P<0.0001) were associated with a significantly greater risk of pSS.

Conclusion

Patients with HPV infections presented with a significantly higher risk of pSS, regardless of age and sex.

Environmental factors in the pathogenesis of primary Sjögren's syndrome

Primary Sjögren's syndrome (SS) is a systemic autoimmune disease in which exocrine organs, primarily the salivary and lacrimal glands, are targets of chronic inflammation, leading to severe dryness of eyes and mouth. Fatigue and arthralgia are also common, and extraglandular manifestations involving the respiratory, nervous and vascular systems occur in a subset of patients. Persistent activation of the type I interferon system, and autoreactive B and T cells with production of disease-associated autoantibodies are central to the pathogenesis. Genetic polymorphisms that associate with an increased risk of SS have been described, though the risk-increase contributed by the respective variant is generally low. It is thus becoming increasingly clear that genetics cannot alone account for the development of SS and that other, presumably exogenous, factors must play a critical role. Relatively few studies have investigated exposure to potential risk factors prior to SS disease onset. Rather, many factors have been studied in prevalent cases. In this review, we summarize current literature on exogenous factors in the pathogenesis of SS including infections, hormones, smoking, solvents and additional compounds. We delineate for which factors there is current evidence of increased disease risk, and for which our present knowledge is confined to suggesting their role in SS pathogenesis. Finally, we outline future perspectives in the continued search for environmental risk factors for SS, a research area of great importance considering the possibilities for preventive measures.

Oral microbial flora of patients with Sicca syndrome

Primary sicca syndrome (pSS) is a systemic autoimmune disease. However, its exact etiology and pathogenesis remain elusive. Various infectious factors have been identified to be closely associated with the occurrence and development of PSS. The present study aimed to assess the composition of the oral microbial flora of patients with pSS in China in order to provide guidance for treatment. The microbial flora of nine patients with pSS and five healthy controls from East China was evaluated in saliva samples using high‑throughput sequencing. A high microbial diversity was detected in the pSS and control groups, with bacteroidetes, firmicutes and proteobacteria constituting the largest phyla in the two groups. Compared with the control group, bacteroidetes and actinobacteria were significantly more abundant in the pSS group, whereas proteobacteria were significantly less abundant. However, no significant differences in bacterial richness and diversity were observed between the two groups. According to a Kyoto Encyclopedia of Genes and Genomes linear discriminant analysis, genes regulating cell apoptosis and the immune and digestive systems were significantly upregulated in the pSS group compared with those in the control group. In conclusion, the present study provided basic data on the flora of the oral cavity in patients with pSS from East China and may serve as a reference for the treatment of this condition.

Risk of dementia among patients with Sjogren's syndrome: A nationwide population-based cohort study in Taiwan

OBJECTIVE

Autoimmunity may play a role in early-stage dementia. The association between Sjogren's syndrome (SS) and dementia remains unknown. This study was conducted to provide epidemiologic evidence for this relationship.

METHODS

This 12-year, nationwide, population-based, retrospective cohort study analyzed the risk of dementia in the SS cohort. We also investigated the incidence of dementia among patients with SS by using data from the Longitudinal Health Insurance Database 2000, maintained by the Taiwan National Health Research Institutes. To balance the prevalence of characteristics in the cohorts, we used the propensity score to match selected comorbidities in the two cohorts. We also analyzed the association between SS and dementia among patients with different potential risks by using a Cox proportional hazard model.

RESULTS

According to the analysis of data obtained from follow-up conducted during 2000-2012, the incidence of dementia in the SS cohort was 1.21-fold that in the control cohort (95% confidence interval [CI] = 1.02-1.45, p < 0.05). In the group older than 65years, the incidence of dementia was significantly high (adjusted hazard ratio [aHR] = 5.30, 95% CI = 4.26-6.60, p < 0.01). After adjustment for comorbidities, including Parkinson's disease (aHR = 2.98, 95% CI = 1.80-4.94), insomnia (aHR = 1.45, 95% CI = 1.14-1.85), and hypertension (aHR = 1.43, 95% CI = 1.19-1.71), the association between SS and dementia was still significant.

CONCLUSION

This 13-year, nationwide, population-based retrospective cohort study revealed patients with SS to have a higher risk of dementia.

Sjögren's syndrome: another facet of the autoimmune/inflammatory syndrome induced by adjuvants (ASIA)

Recently, a new syndrome, namely the "Autoimmune/inflammatory syndrome induced by adjuvants" (ASIA) has been defined. In this syndrome different conditions characterized by common signs and symptoms and induced by the presence of an adjuvant are included. The adjuvant is a substance capable of boosting the immune response and of acting as a trigger in the development of autoimmune diseases. Post-vaccination autoimmune phenomena represent a major issue of ASIA. Indeed, despite vaccines represent a mainstay in the improvement of human health, several of these have been implicated as a potential trigger for autoimmune diseases. Sjogren's Syndrome (SjS) is a systemic chronic autoimmune inflammatory disease characterized by the presence of an inflammatory involvement of exocrine glands accompanied by systemic manifestations. Own to the straight association between infectious agents exposure (mainly viruses) and sicca syndrome development, the possible link between vaccine and SjS is not surprising. Indeed, a few cases of SjS following vaccine delivery have been reported. At the same extent, the induction of SjS following silicone exposure has been described too. Thus, the aim of this review was to focus on SjS and its possible development following vaccine or silicone exposure in order to define another possible facet of the ASIA syndrome.

Autoimmunity and infection in Sjögren's syndrome

PURPOSE OF REVIEW

To summarize the recent developments concerning the potential viral pathomechanisms and involvement of viruses in Sjögren's syndrome, and to highlight the areas for future research and therapies.

RECENT FINDINGS

Activated IFN-1 pathway plays an important part in the autoimmune disease process of Sjögren's syndrome; therefore, several therapies aiming to reduce or inhibit the IFN-1 production and its effects may be a target for future treatment plans. Activated aryl hydrocarbon receptor may interact with latent Epstein-Barr virus (EBV) infection, which in turn may predispose to the development of Sjögren's syndrome. It is estimated that the population is 95% positive for EBV serology. Microbial factors may incite autoimmune disease. Although this hypothesis is proven in a few illnesses such as rheumatic fever, there is no definitive evidence of an infectious environmental trigger in Sjögren's syndrome. However, there are circumstantial data with regard to viruses and several potential mechanisms of disease. These include antigen mimicry, polyclonal lymphocyte activation, and infection-mediated innate end-organ inflammation. In addition, hepatitis C virus infection clearly causes a Sjögren's-syndrome-like illness.

SUMMARY

Data continue to implicate viral infection in the cause of Sjögren's syndrome, but there are no definitive studies incriminating a particular virus.