Novel autoantibodies in Sjögren's syndrome: A comprehensive review

Emerging functions and clinical applications of exosomes in human oral diseases

Exosomes are cell-derived membranous vesicles of endosomal origin secreted by all type of cells and present in various body fluids. Exosomes are enriched in peptides, lipids, and nucleic acids, emerging as vital modulators in intercellular communication. Exosomes are increasingly being evaluated as biomarkers for diagnosis and prognosis of diseases, because the constituents of exosomes could be reprogrammed depending on the states of diseases. These features also make exosomes a research hotspot in oral diseases in recent years. In this review, we outlined the characteristics of exosomes, focused on the differential expressions and altered biological functions of exosomes in oral diseases, including oral squamous cell carcinoma, oral leukoplakia, periodontitis, primary Sjögren's syndrome, oral lichen planus, as well as hand foot and mouth disease. Besides, accumulated evidence documents that it is implementable to consider the natural nanostructured exosomes as a new strategy for disease treatment. Herein, we highlighted the therapeutic potential of exosomes in oral tissue regeneration, oncotherapy, wound healing, and their superiority as therapeutic drug delivery vehicles.

Update on disease pathogenesis, diagnosis, and management of primary Sjögren's syndrome

Primary Sjögren's syndrome (pSS) is a typical multisystem disease, characterized by lymphocytic infiltration of the exocrine glands leading to glandular dysfunction. Multiple systemic manifestations occur in those of serious conditions, with different courses and outcomes. Its pathogenesis is complex, and its diagnosis and management are being constantly updated and improved. We have failed to have much progress in targeted immunotherapy for pSS, and as yet this is still based on empirical treatment. Many studies have tried to define pSS more accurately, to study its pathogenesis, to find effective treatment strategies, opening up new avenues for early diagnosis and precise management of pSS.

Gut microbial dysbiosis in individuals with Sjögren's syndrome

BACKGROUND

Autoimmune diseases have been associated with changes in the gut microbiome. In this study, the gut microbiome was evaluated in individuals with dry eye and bacterial compositions were correlated to dry eye (DE) measures. We prospectively included 13 individuals with who met full criteria for Sjögren's (SDE) and 8 individuals with features of Sjögren's but who did not meet full criteria (NDE) for a total of 21 cases as compared to 21 healthy controls. Stool was analyzed by 16S pyrosequencing, and associations between bacterial classes and DE symptoms and signs were examined.

RESULTS

Results showed that Firmicutes was the dominant phylum in the gut, comprising 40-60% of all phyla. On a phyla level, subjects with DE (SDE and NDE) had depletion of Firmicutes (1.1-fold) and an expansion of Proteobacteria (3.0-fold), Actinobacteria (1.7-fold), and Bacteroidetes (1.3-fold) compared to controls. Shannon's diversity index showed no differences between groups with respect to the numbers of different operational taxonomic units (OTUs) encountered (diversity) and the instances these unique OTUs were sampled (evenness). On the other hand, Faith's phylogenetic diversity showed increased diversity in cases vs controls, which reached significance when comparing SDE and controls (13.57 ± 0.89 and 10.96 ± 0.76, p = 0.02). Using Principle Co-ordinate Analysis, qualitative differences in microbial composition were noted with differential clustering of cases and controls. Dimensionality reduction and clustering of complex microbial data further showed differences between the three groups, with regard to microbial composition, association and clustering. Finally, differences in certain classes of bacteria were associated with DE symptoms and signs.

CONCLUSIONS

In conclusion, individuals with DE had gut microbiome alterations as compared to healthy controls. Certain classes of bacteria were associated with DE measures.

Epithelial Cell Adhesion Molecule in Primary Sjögren's Syndrome Patients: Characterization and Evaluation of a Potential Biomarker

Objective

To determine the subcellular localization of epithelial cell adhesion molecule (EpCAM) in labial salivary gland (LSG) and evaluate the diagnostic use of the extracellular domain of EpCAM (EpEX) and intracellular domain (EpICD) for primary Sjögren's syndrome (pSS).

Methods

Immunohistochemical (IHC) analysis was conducted using EpEX and EpICD domain-specific antibodies on labial salivary gland biopsy (LSGB) from participants. Chi-square or Fisher's exact analysis, Mann-Whitney U-test, and Kruskal-Wallis test compared differences among groups. Independent risk factors of pSS were determined by multiple logistic regression analysis. Receiver-operator characteristic curves (ROC) were carried out to estimate the diagnostic value.

Results

Compared to non-SS controls, loss of membranous EpEX and EpICD expression was observed in LSGB of pSS patients, which occurred in parallel with increased accumulation of cytoplastic and nuclear EpICD. The subcellular EpEX/EpICD expressions were associated with various features of pSS patients, especially histopathological grade of LSGB. Furthermore, high IHC scores of membranous EpEX were independent risk factors for pSS, even for the pSS patients at early stage. The IHC scores of subcellular EpEX/EpICD were of great diagnostic value for pSS with high sensitivity (70-80%) and specificity (85-95%).

Conclusion

This study first found the aberrant expression pattern of EpCAM in LSG of pSS patients. The IHC scores of subcellular EpEX/EpICD were demonstrated to have the potential to act as diagnostic biomarkers for pSS.

Evaluation of patients with dry eye for the presence of primary or secondary Sjӧgren's syndrome

PURPOSE

To assess the frequency of Sjӧgren's syndrome (SS), either primary or secondary to rheumatic disease, in a cohort of patients with aqueous-deficient dry eye and to determine the most accurate objective test for diagnosis of SS.

METHODS

A total of 111 patients with dry eye were recruited from Minia University's ​Ophthalmology Outpatient Clinic (69 patients) and Rheumatology Outpatient Clinic (42 patients). The patients were screened for aqueous tear-deficient dry eye by abnormal test results of Schirmer test I (<10 mm) and tear-film break-up time (<10 seconds) in at least one eye. The diagnosis of SS was made according to the 2012 American College of Rheumatology​ criteria. A complete work up for SS was performed, including clinical examination, serological tests, ocular tests, and labial salivary-gland biopsy (LSGB).

RESULTS

Of the 111 patients, 58 had aqueous-deficient dry eye: 23 in the ophthalmology clinic cohort (group I) and 35 in the rheumatology clinic cohort (group II). Three patients had pSS, and its frequency was 13% in group I and 5.2% among all studied patients. The ocular staining score is the most diagnostic ocular test (sensitivity 100% and specificity 90.9%). Anti-SSA/Ro antibody is the most accurate serological method (sensitivity 33.3% and specificity 100%). LSGB histopathology is the most diagnostic method for SS, with sensitivity, specificity, and positive and negative predictive values of 100%.

CONCLUSION

SS was detected with reasonable frequency among dry-eye patients, particularly pSS. Screening of dry eye for SS can select SS patients early in the disease course.

Potential Implications of Long Noncoding RNAs in Autoimmune Diseases

Long noncoding RNAs (lncRNAs) are non-protein coding RNAs of more than 200 nucleotides in length. Despite the term “noncoding”, lncRNAs have been reported to be involved in gene expression. Accumulating evidence suggests that lncRNAs play crucial roles in the regulation of immune system and the development of autoimmunity. lncRNAs are expressed in various immune cells including T lymphocytes, B lymphocytes, macrophages, neutrophils, dendritic cells, and NK cells, and are also involved in the differentiation and activation of these immune cells. Here, we review recent studies on the role of lncRNAs in immune regulation and the differential expression of lncRNAs in various autoimmune diseases.