Signal hyperintensities on brain magnetic resonance imaging in patients with primary Sjögren syndrome and frequent episodic tension-type headache: relation to platelet serotonin level and disease activity

Central Nervous System Involvement in Primary Sjögren's Syndrome: Narrative Review of MRI Findings

Central nervous system (CNS) involvement is one of the numerous extraglandular manifestations of primary Sjögren's syndrome (pSS). Moreover, neurological complaints precede the sicca symptoms in 25-60% of the cases. We review the magnetic resonance imaging (MRI) lesions typical for pSS, involving the conventional examination, volumetric and morphometric studies, diffusion tensor imaging (DTI) and resting-state fMRI. The most common radiological lesions in pSS are white matter hyperintensities (WMH), scattered alterations hyperlucent on T2 and FLAIR sequences, typically located periventricularly and subcortically. Cortical atrophy and ventricular dilatation can also occur in pSS. Whilst these conditions are thought to be more common in pSS than healthy controls, DTI and resting-state fMRI alterations demonstrate evident microstructural changes in pSS. As pSS is often accompanied by cognitive symptoms, these MRI alterations are expectedly related to them. This relationship is not clearly delineated in conventional MRI studies, but DTI and resting-state fMRI examinations show more convincing correlations. In conclusion, the CNS manifestations of pSS do not follow a certain pattern. As the link between the MRI lesions and clinical manifestations is not well established, more studies involving larger populations should be performed to elucidate the correlations.

Identification of definitive serum biomarkers associated with disease activity in primary Sjögren's syndrome

Background

In this study, we sought to identify definitive biomarkers associated with disease activity in primary Sjögren’s syndrome (pSS).

Methods

Serum protein concentrations in pSS patients and healthy controls (HCs) were comprehensively screened using high-throughput proteomic analysis, and differentially expressed proteins were extracted. Correlation between differentially expressed proteins and European League Against Rheumatism Sjögren’s Syndrome Disease Activity Index (ESSDAI) scores was analyzed and disease activity-associated biomarkers were identified. These biomarkers were validated by enzyme-linked immunosorbent assay (ELISA) in a separate pSS cohort.

Results

The serum concentrations of 1100 proteins were compared between 30 pSS patients and 30 HCs, with 82 differentially expressed proteins identified as pSS-associated proteins. Of these 82 proteins, 9 were identified as disease activity-associated biomarkers. These nine biomarkers underwent validation by ELISA in a separate pSS validation cohort (n = 58), with five proteins (CXCL13, TNF-R2, CD48, B-cell activating factor (BAFF), and PD-L2) subsequently being confirmed as candidate biomarkers. Of these five candidate biomarkers, CXCL13 exhibited the most significant correlation with the lymphadenopathy, glandular, and pulmonary domains of the ESSDAI. CXCL13, TNF-R2 and CD48 exhibited a positive correlation with the biological domain of the ESSDAI. TNF-R2 exhibited the most negative correlation with uptake in the submandibular gland on technetium 99m-pertechnetate salivary gland scintigraphy.

Conclusions

Our approach successfully identified serum biomarkers associated with disease activity in pSS patients. These markers might be potential therapeutic targets in pSS patients.

Electronic supplementary material

The online version of this article (doi:10.1186/s13075-016-1006-1) contains supplementary material, which is available to authorized users.

Serotonin transporter gene polymorphisms: Relation with platelet serotonin level in patients with primary Sjogren's syndrome

Significantly lower platelet serotonin level (PSL) in patients with primary Sjogren's syndrome (pSS) than in healthy controls has been reported in our prior studies. In the present report, we demonstrated effect of functional polymorphisms in the serotonin transporter gene (5-HTT) on PSL. We describe a group of 61 pSS patients and 100 healthy individuals subjects, who received PSL measurement in our prior study. All subjects were genotyped for the promoter 5-HTTLPR (L/S), rs25531 (A/G) and intronic 5-HTTVNTRin2 (l/s) polymorphisms. Overall, the presence of 5-HTTVNTRin2 ss genotype was associated with significantly lower PSL in pSS patients, not in healthy controls. Reduced PSL in pSS patients is in line with hypothesis of association between chronic immunoinflammation and 5-HT system dysregulation, identifying additional mechanisms such as altered 5-HT transport as potential genetic factor contributing to PSL depletion.

Beyond the Glands: An in-Depth Perspective of Neurological Manifestations in Sjögren's Syndrome

Primary Sjögren’s Syndrome (pSjS) is an autoimmune disease characterized by sicca (xerophthalmia or xerostomia) symptoms, anti-SS-A (Ro) or anti-SS-B (La) autoantibodies, and lymphocytic infiltrates in the exocrine glands. Disease incidence is estimated to be 0.1–3% of the general population with 0.4–3.1 million individuals in the US with women being nine times more likely to be afflicted with SjS than men. The frequency continues to rise accompanied with the multi-factorial etiology making it a challenging disease to manage and treat. Treatment of this disease remains problematic due to the lack of therapeutic treatments relying on replacement therapies such as artificial saliva and eye lubricants or immunosuppressive agents. To further complicate the management of the disease, there are number of multi-systemic manifestations specifically peripheral neuropathy associated with later stage of disease onset. Increasingly, there is mounting evidence that suggests the involvement of central nervous system. It remains to be determined the underlying cause and effect of the dysregulated immune response and the neuropathy associated with SjS. In this review, we provided an in-depth look at key neurological dysfunctions documented to occur in pSjS. Specifically, we discussed the prevalence, symptomology, and current treatments.