Parkinsonism and Sjögren's Syndrome: A Fortuitous Association or a Shared Immunopathogenesis?

Regional brain function study in patients with primary Sjögren's syndrome

BACKGROUND

Primary Sjögren's syndrome (pSS) manifests a spectrum of neuropsychological symptoms, primarily cognitive impairment, but the mechanism of central nervous system damage remains unclear. This study sought to analyze differences in the static and dynamic fractional amplitude of low-frequency fluctuation (fALFF) and region homogeneity (ReHo) between pSS patients and healthy controls (HCs), aiming to elucidate regional brain function alterations and investigate underlying mechanisms.

METHODS

Using stringent inclusion and exclusion criteria, 68 pSS patients and 69 HCs were assessed, including rs-fMRI, neuropsychological assessments, and laboratory tests. Static fALFF (sfALFF), static ReHo (sReHo), dynamic fALFF (dfALFF), and dynamic ReHo (dReHo) were calculated separately using two-sample t-tests to identify differences in brain regions between the two groups. Correlations between these regions and disease duration, laboratory indicators, and neuropsychological test scores were also examined.

RESULTS

Static index analysis revealed increased sfALFF in the right supplementary motor area in pSS patients, with significant decreases in sReHo in the left orbital media frontal gyrus, left caudate nucleus, and right precuneus lobe. Dynamic index analysis showed significant increases in dfALFF in the left supplementary motor area and dReHo in the right dorsolateral superior frontal gyrus. Furthermore, sReHo in the right precuneus lobe negatively correlated with NCT-A scores (P = 0.005), and dReHo in the right dorsolateral superior frontal gyrus negatively correlated with DST scores (P = 0.007).

CONCLUSION

PSS patients experience notable changes in regional brain function, as evidenced by alterations in both static and dynamic brain indicators. Integrating these metrics provides a holistic view of the brain function alterations in pSS patients.

Diversity of central nervous system manifestations in Sjogren's Disease: a case-based review

Sjogren's disease (SjD) is a chronic and disabling autoimmune disease, predominantly characterized by dryness of the mouth and eyes, resulting from lymphocytic infiltration of exocrine glands. While these are the most prominent symptoms, extra-glandular manifestations are also common. Studies suggest that up to 70% of SjD patients experience neurological symptoms, which interestingly often precede the hallmark dryness. Although every structure of the nervous system can be affected, disorders of peripheral nervous system (PNS) are more common than central nervous system (CNS) involvement. The CNS manifestations can range from subtle to severe, with some patients experiencing a rapid progression of symptoms. The literature documents cases where patients initially diagnosed with Creutzfeldt-Jakob disease, neurosarcoidosis, temporary hemiplegia, neuromyelitis optica, or epilepsy were ultimately diagnosed as having SjD. Here, we present five SjD patient cases, each with a different manifestation of CNS involvement, along with an overview of the current understanding of CNS disorders in the course of the disease. In four cases, the neurological manifestations appeared before the onset of sicca symptoms. In one patient, diagnosis was delayed by 15 years due to an atypical presentation. After receiving immunosuppression, all patients experienced notable alleviation of their symptoms.

Identification and verification of inflammatory biomarkers for primary Sjögren's syndrome

INTRODUCTION

Primary Sjögren's syndrome (pSS) is an autoimmune disease characterized by inflammatory infiltration, and dysfunction of the salivary and lacrimal glands. This research aimed to explore the disease pathogenesis and improve the diagnosis and treatment of pSS by mining inflammation-associated biomarkers.

METHODS

Five pSS-related datasets were retrieved from the Gene Expression Omnibus (GEO) database. Inflammation-associated biomarkers were determined by the least absolute shrinkage and selection operator (LASSO) and support vector machines recursive feature elimination (SVM-RFE). Single sample gene set enrichment analysis (ssGSEA) was implemented to profile the infiltration levels of immune cells. Real-time quantitative PCR (RT-qPCR) verified the expression of biomarkers in clinical samples.

RESULTS

Four genes (LY6E, EIF2AK2, IL15, and CXCL10) were screened as inflammation-associated biomarkers in pSS, the predictive performance of which were determined among three pSS-related datasets (AUC > 0.7). Functional enrichment results suggested that the biomarkers were involved in immune and inflammation-related pathways. Immune infiltration analysis revealed that biomarkers were notably connected with type 2 T helper cells, regulatory T cells which were significantly expressed between pSS and control. TESTOSTERONE and CYCLOSPORINE were predicted to take effect by targeting CXCL10 and IL15 in pSS, respectively.

CONCLUSION

Four inflammation-associated biomarkers (LY6E, EIF2AK2, IL15, and CXCL10) were explored, and the underlying regulatory mechanisms and targeted drugs associated with these biomarkers were preliminarily investigated according to a series of bioinformatics methods based on the online datasets of pSS, which provided a reference for understanding the pathogenesis of pSS. Key Points • Inflammation-associated biomarkers (LY6E, EIF2AK2, IL15, and CXCL10) were firstly identified in Sjögren's syndrome based on LASSO and SVM-RFE analyses. • CXCL10, EIF2AK2 and LY6E were prominently positively correlated with immature B cells, while IL15 were significantly negatively correlated with memory B cells in Sjögren's syndrome. • LY6E, EIF2AK2, IL15, and CXCL10 were significantly more highly expressed in clinical Sjögren's syndrome samples compared to healthy control samples, which was consistent with the analysis results of the GEO database. •LY6E, EIF2AK2, IL15, and CXCL10 might be used as the biomarkers for the treatment and diagnosis of Sjögren's syndrome.

Subacute Progressive Hearing Loss and Lower Body Parkinsonism in Primary Sjögren's Syndrome

In primary Sjögren's syndrome, it is extremely rare to observe subacute progressive lower-body parkinsonism with severe sensory hearing loss responsive to corticosteroid therapy. Sjögren's syndrome can cause heterogeneous symptoms; therefore, its diagnosis and introduction of treatment are prone to be delayed, particularly in cases without sicca symptoms or seronegative cases, which are more likely to be seen in patients with neurological complications. This report may help clinicians identify atypical early neurological symptoms in primary Sjögren's syndrome.

Causal relationships between Sjögren's syndrome and Parkinson's disease: A Mendelian randomization study

BACKGROUND

Epidemiological and observational studies have indicated an association between Sjögren's syndrome (SS) and Parkinson's disease (PD). However, consistent conclusions have not been reached due to various limitations. In order to determine whether SS and PD are causally related, we conducted a Mendelian randomization study (MR) with two samples.

METHODS

Data for SS derived from the FinnGen consortium's R9 release (2495 cases and 365 533 controls). Moreover, data for PD were acquired from the publicly available GWAS of European ancestry, which involved 33 674 cases and 449 056 controls. The inverse variance weighted, along with four other effective methodologies, were employed to comprehensively infer the causal relationships between SS and PD. To assess the estimation's robustness, a number of sensitivity studies were performed. To determine the probability of reverse causality, we performed a reverse MR analysis.

RESULTS

There was no evidence of a significant causal effect of SS on PD risks based on the MR [odds ratio (OR) = 1.03; 95% confidence interval (CI) = 0.95-1.11; p = .45]. Similarly, no evidence supported the causal effects of PD on SS (OR = 0.92; 95% CI = 0.81-1.04; p = .20). These findings held up under rigorous sensitivity analysis.

CONCLUSIONS

MR bidirectional analysis did not reveal any cause-and-effect relationship between SS and PD, or vice versa. Further study of the mechanisms that may underlie the probable causal association between SS and PD is needed.

Risk of dementia or Parkinson's disease in the presence of Sjögren's syndrome: A systematic review and meta-analysis

Objective

Evidence from observational studies suggests that Sjögren's syndrome (SS) may contribute to an elevated risk of Parkinson's disease (PD) and dementia. However, few studies have been undertaken to summarize and assess the consistency of the data quantitatively. Therefore, we evaluated the risk of dementia and PD in SS patients through a systematic review and meta-analysis approach.

Methods

Two reviewers independently conducted a systematic search of PubMed, Embase, and Web of Science databases (updated to February 14, 2022) to identify published literature on the association between SS and dementia or PD. The risk estimates of dementia or PD in patients with SS were pooled using fixed or random-effects models.

Results

Of the 631 studies initially searched, 10 were eventually included. Pooled results suggested that the risk of developing dementia significantly increased in patients with SS (HR = 1.24, 95% CI: 1.15-1.33, P < 0.001), and such risk in females with SS was similar to that in males. The risk of PD was 1.36 times higher in SS (HR = 1.36, 95% CI: 1.23-1.50, P < 0.001). The association between SS and PD risk appeared to occur primarily in female patients (female: HR = 1.28, 95% CI: 1.21-1.35; P < 0.001 vs. male: HR = 1.00, 95% CI: 0.87-1.16, P = 0.962, respectively). No significant effect of age was observed on the risk of developing PD and dementia in SS patients.

Conclusion

Our study supports that people with SS are at higher risk of PD and dementia than the general population. Further studies are needed to elucidate the underlying mechanisms and to assess whether interventions for SS have the potential to affect dementia and PD development.

Movement disorders in systemic autoimmune diseases: Clinical spectrum, ancillary investigations, pathophysiological considerations

With the advances in neuroimmunology especially due to the discovery of new neuronal antibodies, the recognition of treatable antibody-related movement disorders has recently received much attention. In contrast, the identification and characterisation of movement disorders associated with systemic autoimmune diseases remains a substantially unexplored area. Beyond the classic few associations such as chorea and antiphospholipid syndrome, or ataxia and coeliac disease, movement disorders have been reported in association with several systemic autoimmune diseases, however a clear image of clinical phenotypes, investigations, and treatment outcomes in these conditions has never been drawn. In this review, we analyse data from approximately 300 cases and summarise the epidemiological, clinical and diagnostic features of movement disorders associated with systemic autoimmune diseases, and the available knowledge about treatment and outcomes. We highlight that movement disorders in systemic autoimmune conditions are frequently the only or among a few presenting manifestations and are mostly treatable disorders responding to immunotherapy or dietary modifications. We point out the pertinent combination of clinical features and investigations which can suggest the underlying autoimmune nature of these movement disorders, and thus address the most appropriate treatment.

Impact of Sjogren's syndrome on Parkinson's disease: A nationwide case-control study

Objective

To investigate whether Sjogren’s syndrome would have an influence on the development of Parkinson’s disease.

Methods

A population-based case-control study was conducted. Participants consisted of 7716 subjects with newly diagnosed Parkinson’s disease and a population of 75129 matched control subjects between 2000 and 2010. We measured the risk of Parkinson’s disease in association with Sjogren’s syndrome by using adjusted odds ratios.

Results

A total of 143 Parkinson’s disease subjects (1.9%) and 893 control subjects (1.2%) suffered from Sjogren’s syndrome (p < 0.001). The crude odds ratio for Parkinson’s disease among subjects with Sjogren’s syndrome was 1.56 (95% CI 1.30–1.86; p < 0.01). After adjustment for potential confounders which have been proposed that would increase the risk of development of Parkinson’s disease, Sjogren’s syndrome was found to be significantly associated with the risk of Parkinson’s disease with an odds ratio of 1.37 (95% CI 1.15–1.65; p < 0.01).

Conclusion

This study preliminarily proposed that Sjogren’s syndrome was significant associated with an increased risk of Parkinson’s disease.