Analysis of novel Sjogren's syndrome autoantibodies in patients with dry eyes

Updates in diagnostics, treatments, and correlations between oral and ocular manifestations of Sjogren's syndrome

Sjogren's syndrome (SS) is characterized as an autoimmune disorder targeting secretory glands, including the lacrimal and salivary glands, causing dry eye and dry mouth predominantly in women over the age of 40. In this review, we summarize recent advancements in SS diagnostics, treatments, and our understanding of correlations between oral and ocular manifestations of SS. Google Scholar and PubMed databases were utilized to search peer-reviewed papers since 2016 on SS diagnosis, treatment, and correlations between oral and ocular manifestations. For diagnostics, we discuss the updated SS classification criteria by the American College of Rheumatology/European League Against Rheumatism (ACR/EULAR), new biomarkers, and compare studies of current diagnostic methods with alternative technologies. For treatments, we discuss topical, systemic, and surgical treatment developments in the management of oral and ocular symptoms of SS as there is still no cure for the disorder. Finally, we report studies that directly suggest correlations between the ocular surface disease and oral disease in SS, as well as shared abnormalities in the microbiome and cytokine expression that may be correlated. We conclude by stating limitations to our review as well as paths moving forward. Elucidating correlations between oral and ocular manifestations may be the key to furthering our understanding of SS pathogenesis as well as defining new standards for diagnosis and treatment.

Dry eye in Sjögren's syndrome - characteristics and therapy

BACKGROUND

Sjögren's syndrome is an autoimmune disease, and its important feature is the lymphocyte infiltration of exocrine glands, including lacrimal glands. It contributes to defects of their activity and causes that one of the main manifestation of Sjögren's syndrome is dry eye. Unfortunately, the discrimination between dry eye related and non-related to Sjögren's syndrome is difficult at the initial stages of diseases. In addition, the available agents for the treatment of Sjögren's syndrome-related dry eye have limited efficacy.

AIM

The purpose of this study was to describe and emphasize differences between Sjögren's Syndrome-related dry eye and non-Sjögren's Syndrome-related dry eye together with the determination of novel therapeutic options for Sjögren's Syndrome-related dry eye.

METHOD

A review of the relevant papers describing characteristics of Sjögren's Syndrome-related dry eye and its therapy was conducted. This article is based on both pre-clinical and clinical evidences.

RESULTS

On the basis of our analysis, we indicated differences between Sjögren's Syndrome-related dry eye and non-Sjögren's Syndrome-related dry eye. Moreover, there are some novel markers that could be used in the diagnosis of Sjögren's Syndrome-related dry eye. In addition, expect artificial tear, other agents e.g. hydroxychloroquine can be effective in therapy of disease.

CONCLUSIONS

Sjögren's Syndrome-related dry eye is a disorder, whose diagnosis may be difficult and mistaken for non-Sjögren's Syndrome-related dry eye. However, Sjögren's Syndrome-related dry eye has some specific features. In addition, the development of newer and safer therapeutic agents for Sjögren's syndrome-related dry eye is needed, and therefore further clinical, randomized studies are necessary.

Biomarkers of B cell activation in autoimmune connective tissue diseases: More than markers of disease activity

B cells play a central role in the pathogenesis of many autoimmune diseases, acting as antigen-presenting cells, producing inflammatory cytokines, and acting as a source of autoantibodies after differentiating into plasma cells. In this review, we aim to summarize and synthesize the literature for the utility of biomarkers of B cell activation (plasma immunoglobulins (Ig), free light chains (FLCs), and beta-2 microglobulin (β2M)) in monitoring inflammatory rheumatic connective tissue diseases, such as Sjogren's syndrome (SS), systemic lupus erythematosus (SLE), dermatomyositis (DM), and systemic sclerosis (SSc). Clinically, it is quite difficult to gauge prognosis in these conditions as there, historically, have not been many quantitative markers of disease activity available. From our extensive literature review, Ig, FLC, and β2M may function as invaluable prognostic markers of ongoing disease activity, and potentially as biomarkers for response to therapy or disease relapse. They are inexpensive and unsophisticated tests that are vastly underused in the setting of autoimmune disease. However, clinicians still need to be aware of the potential of false positives in times of infection or plasma cell dyscrasia, as these disease states can artificially increase these biomarkers. Ultimately, the utility of serum Ig, FLCs, and β2M is clearly delineated in SS and SLE, and least investigated in DM, and additional prospective studies utilizing these biomarkers, and specific B cell targeted therapies are still needed.

The Diagnostic Performance of Early Sjögren's Syndrome Autoantibodies in Juvenile Sjögren's Syndrome: The University of Florida Pediatric Cohort Study

Objectives

The aim of this study was to evaluate the clinical validity of early Sjögren's syndrome (SS) autoantibodies (eSjA), which were originally marketed for early diagnosis of SS, for juvenile SS (JSS) in a recently identified pediatric cohort.

Methods

A total of 105 symptomatic subjects with eSjA results available were evaluated at the Center for Orphaned Autoimmune Disorders at the University of Florida and enrolled for this study. JSS diagnosis was based on the 2016 ACR/EULAR SS criteria. Demographic/clinical/laboratory parameters were compared between JSS (n = 27) and non-JSS (n = 78) for % positivity, sensitivity, and specificity of eSjA (SP1, anti-salivary protein; CA6, anti-carbonic anhydrase VI; PSP, anti-parotid secretory protein) and classic SS-autoantibodies (cSjA; ANA, SSA/SSB, RF, and others) either alone or in combination. Associations between eSjA and diagnostic/glandular parameters were also determined by Fisher's exact test.

Results

Compared to non-JSS, JSS patients exhibited sicca symptoms demonstrating reduced unstimulated salivary flow rate (USFR) and abnormal glandular features revealed by salivary gland ultrasound (SGUS). Among cSjA, ANA demonstrated the highest sensitivity of 69.2%, while SSA, SSB, and RF showed around 95% specificities for JSS diagnosis. The % positive-SSA was notably higher in JSS than non-JSS (56% vs. 5%). Of eSjA, anti-CA6 IgG was the most prevalent without differentiating JSS (37%) from non-JSS (32%). Sensitivity and specificity of eSjA were 55.6 and 26.9%, respectively. Autoantibodies with potentially applicable specificity/sensitivity for JSS were seen only in cSjA without a single eSjA included. There were no associations detected between eSjA and focus score (FS), USFR, SSA, SGUS, and parotitis/glandular swelling analyzed in the entire cohort, JSS, and non-JSS. However, a negative association between anti-PSP and parotitis/glandular swelling was found in a small group of positive-SSA (n = 19, p = 0.02) whereas no such association was found between anti-PSP-positive compared to anti-PSP-negative. JSS and non-JSS groups differed in FS, USFR, and EULAR SS Patient Reported Index Dryness/Mean in CA6/PSP/ANA, SP1, and SSA-positive groups, respectively. Additionally, a higher FS was found in RF-positive than RF-negative individuals.

Conclusions

eSjA underperformed cSjS in differentiating JSS from non-JSS. The discovery of clinical impact of eSjA on early diagnosis of JSS necessitates a longitudinal study.

Association Between Early Sjögren Markers and Symptoms and Signs of Dry Eye

PURPOSE

Animal models suggest that early markers of Sjögren syndrome (EMS)-antibodies against salivary protein 1, parotid secretory protein, and carbonic anhydrase 6 (CA6)-are more accurate signals of early Sjögren when compared with classic markers (anti-Ro and anti-La). To further understand the relationship between EMS and dry eye (DE), we compared symptoms and signs of DE in subjects who tested positive versus negative for EMS.

METHODS

In this cross-sectional study, patients at the Miami Veterans Affairs Eye Clinic who were tested for EMS underwent a standard ocular surface examination. Indications for EMS testing included DE symptoms in combination with dry mouth symptoms, low tear production, corneal staining, or a Sjögren disease-associated autoimmune disease. Statistical tests performed were the χ test, Fisher exact test, independent sample t test, and Spearman correlation.

RESULTS

Seventy-three percent of 44 patients tested positive for 1 or more EMS. CA6 IgG was most frequently elevated, followed by CA6 IgM and parotid secretory protein IgG. EMS-positive versus EMS-negative subjects were more likely to escalate DE treatment past artificial tears to topical cyclosporine (n = 32, 100% vs. n = 9, 75%, P = 0.02). There were no demographic or comorbidity differences between EMS-positive and EMS-negative subjects, and marker levels did not correlate with more severe tear film measures.

CONCLUSIONS

Most of the individuals with DE tested positive for 1 or more EMS antibodies, including men and Hispanics. Future studies will be needed to understand how to incorporate EMS data into the care of an individual with DE.

Disease-Specific Expression of Conjunctiva Associated Lymphoid Tissue (CALT) in Mouse Models of Dry Eye Disease and Ocular Allergy

Conjunctiva-associated tissue (CALT) is assumed to play a crucial role in the immune system of the ocular surface. Its function in several ocular surface diseases (OSD) is still not fully understood. This study investigates the function of CALT in mouse models of dry-eye disease and ocular allergy. Since antigen-presentation is the central similarity in the pathologies, this study focuses on antigen-presentation in CALT Morphology and the expression of CALT, which was investigated in mice after induction of dry-eye, ocular allergy, topical antigen-stimulation, and after local depletion of phagocytic cells. Antigen uptake was investigated after the application of fluorescent ovalbumin (OVA). OSD influences the appearance and morphology of CALT in a disease-dependent manner. Ocular allergy leads to an increase and dry-eye disease to a decrease in number and size of CALT. The development of CALT is dependent on the presence of APCs. Professional APCs are present in CALT, and soluble antigen is transported into the follicle. CALT appearance is disease-specific and indicative of differing functions. Although the specific involvement of CALT in OSD needs further study, the existence of functional APCS and antigen-uptake supports the hypothesis that CALT is an immunological key player at the ocular surface.

Current State of Knowledge on Primary Sjögren's Syndrome, an Autoimmune Exocrinopathy

Primary Sjögren's syndrome (pSS) is a chronic systemic autoimmune rheumatic disease characterized by lymphoplasmacytic infiltration of the salivary and lacrimal glands, whereby sicca syndrome and/or systemic manifestations are the clinical hallmarks, associated with a particular autoantibody profile. pSS is the most frequent connective tissue disease after rheumatoid arthritis, affecting 0.3-3% of the population. Women are more prone to develop pSS than men, with a sex ratio of 9:1. Considered in the past as innocent collateral passive victims of autoimmunity, the epithelial cells of the salivary glands are now known to play an active role in the pathogenesis of the disease. The aetiology of the "autoimmune epithelitis" still remains unknown, but certainly involves genetic, environmental and hormonal factors. Later during the disease evolution, the subsequent chronic activation of B cells can lead to the development of systemic manifestations or non-Hodgkin's lymphoma. The aim of the present comprehensive review is to provide the current state of knowledge on pSS. The review addresses the clinical manifestations and complications of the disease, the diagnostic workup, the pathogenic mechanisms and the therapeutic approaches.

Prevalence of Novel Candidate Sjögren Syndrome Autoantibodies in the Penn Sjögren's International Collaborative Clinical Alliance Cohort

PURPOSE

To evaluate the prevalence of novel candidate autoantibodies associated with Sjögren syndrome (SS) and their ability to identify those with SS among participants with dry eye enrolled in the Sjögren's International Collaborative Clinical Alliance (SICCA) study at the University of Pennsylvania (Penn).

METHODS

All participants previously underwent a full ocular and systemic evaluation for possible SS as part of the SICCA study. An enzyme-linked immunosorbent assay was used to detect IgG, IgA, and IgM autoantibodies to salivary protein 1 (SP-1), parotid secretory protein (PSP), and carbonic anhydrase 6 from previously banked baseline serum samples from SICCA study participants enrolled at Penn. The prevalence rate of each autoantibody, calculated by considering the presence of any isotype as antibody positive, was compared between participants with dry eye with SS (n = 81) or without SS (n = 129) using the Fisher exact test.

RESULTS

The prevalence of SP-1 IgM autoantibodies was higher in those with SS compared with those without SS (14% vs. 5%; P = 0.03). Similarly, the prevalence of PSP IgA autoantibodies was higher in those with SS compared with non-SS dry eye participants (21% vs. 11%; P = 0.048). There was no statistically significant difference in the prevalence of carbonic anhydrase 6 autoantibodies between those with or without SS (15% vs. 20%; P = 0.36).

CONCLUSIONS

In the Penn SICCA cohort, SP-1 IgM and PSP IgA autoantibodies were more prevalent in the serum of SS-related dry eye participants compared with those without SS. Further longitudinal studies are needed to determine the clinical significance of these findings.

Role of tear film biomarkers in the diagnosis and management of dry eye disease

In recent years, there has been increasing scientific interest in the use of tear film biomarkers in the diagnosis and management of dry eye disease (DED), owing to their potential important roles in the pathogenesis of ocular surface damage, as well as the technical feasibility of tear sample collection techniques. An Entrez PubMed search was conducted on March 2, 2019, to include papers investigating the use of tear film biomarkers in DED, and the results were classified according to whether the DED is associated with systemic inflammatory disease or not and further classified within each section according to the molecular nature of the biomarker for further discussion. A total of 58 relevant articles were reviewed. Certain cytokines, including interleukin-6 (IL-6), tumor necrosis factor-alpha, IL-17, and IL-8, were found by a number of studies to consistently reflect disease severity well and had strong correlations with tear film metrics and tests for ocular surface damage in dry eye without systemic inflammatory disease. For dry eye with systemic inflammatory disease, IL-17, IL-8, and IL-1 receptor antagonists were shown to be consistently higher in affected eyes and correlated well with ocular surface disease severity in more than one type of inflammatory disease. With the advancement in technology and lowered costs in the future, tear film biomarker counts would allow better diagnosis and monitoring of DED, as well as facilitate personalized treatment strategies.

Carbonic Anhydrase 6 Gene Variation influences Oral Microbiota Composition and Caries Risk in Swedish adolescents

Carbonic anhydrase VI (CA6) catalyses the reversible hydration of carbon dioxide in saliva with possible pH regulation, taste perception, and tooth formation effects. This study assessed effects of variation in the CA6 gene on oral microbiota and specifically the acidophilic and caries-associated Streptococcus mutans in 17-year old Swedish adolescents (n = 154). Associations with caries status and secreted CA6 protein were also evaluated. Single Nucleotide Polymorphisms (27 SNPs in 5 haploblocks) and saliva and tooth biofilm microbiota from Illumina MiSeq 16S rDNA (V3-V4) sequencing and culturing were analysed. Haploblock 4 (rs10864376, rs3737665, rs12138897) CCC associated with low prevalence of S. mutans (OR (95% CI): 0.5 (0.3, 0.8)), and caries (OR 0.6 (0.3, 0.9)), whereas haploblock 4 TTG associated with high prevalence of S. mutans (OR: 2.7 (1.2, 5.9)) and caries (OR: 2.3 (1.2, 4.4)). The TTG-haploblock 4 (represented by rs12138897(G)) was characterized by S. mutans, Scardovia wiggsiae, Treponema sp. HOT268, Tannerella sp. HOT286, Veillonella gp.1 compared with the CCC-haploblock 4 (represented by rs12138897(C)). Secreted CA6 in saliva was weakly linked to CA6 gene variation. In conclusion, the results indicate that CA6 gene polymorphisms influence S. mutans colonization, tooth biofilm microbiota composition and risk of dental caries in Swedish adolescents.

Clinical Correlations of Novel Autoantibodies in Patients with Dry Eye

Background

Diagnostic criteria for Sjögren's syndrome (SS) are continually being updated in pursuit of more precise and earlier diagnosis to prevent its complications. Owing to the high rate of false negative traditional serological markers, the need for better serological testing remains.

Objective

To investigate the clinical significance of three recently discovered novel autoantibodies, anti-salivary gland protein 1 (SP1), anti-carbonic anhydrase 6 (CA6), and anti-parotid secretory protein (PSP), in a cohort of dry eye patients with suspected underlying inflammatory/autoimmune disease.

Methods

Medical records of 136 patients with a primary diagnosis of dry eye who underwent laboratory testing between April 2014 and July 2017 were reviewed retrospectively. Data regarding demographic information, ocular and systemic symptoms, previous medical diagnoses, serological test results, and minor salivary gland biopsy results were collected. Dry eye evaluations included tear osmolarity, Schirmer test without anesthesia, conjunctival lissamine green staining, and corneal fluorescein staining in the order listed here.

Results

Of the 136 patients, 9 (9/136, 6.6%) presented with a history of SS, and 9 additional patients (9/127, 7%) received a new diagnosis of SS as a result of evaluations. Fifty-six patients (56/136, 41%) tested positive for at least one of the novel autoantibodies. Fifty-four percent (6/11) of patients with primary SS who underwent the novel serological testing had a positive anti-PSP. Of those, 2 (2/11, 18%) had negative traditional serology and had to undergo minor salivary gland biopsy for definitive diagnosis. Anti-CA6 was associated with increased corneal and conjunctival staining after adjusting for age, sex, and other serologic markers (HR = 1.5, 95% CI = 1.20-1.97, and p = 0.009 and HR = 1.4, 95% CI = 1.04-1.76, and p = 0.02, respectively).

Conclusions

This cross-sectional study demonstrated that anti-CA6 is seen in patients with severe aqueous-deficient dry eye. Whether these patients have an early stage of SS or a different type of autoimmune condition may be determined through longitudinal studies.

Novel autoantibodies in Sjögren's syndrome: A comprehensive review

Sjögren's syndrome is a systemic autoimmune disease characterized by immune- mediated injury of exocrine glands, as well as a diverse array of extraglandular manifestations. B cell over-activation is a key feature of the disease, attested by the wide spectrum of autoantibodies detected in these patients. Up to date, anti- Ro/SSA and anti-La/SSB antibodies are traditional biomarkers for disease classification and diagnosis. On the other hand, the detection of novel autoantibodies in SS has increased in the last years, opening a window of opportunity to denote particular stages of the disease, to establish clinical phenotypes, and to predict long-term complications such as lymphoma. For instance, anti-SP-1, anti-CA6 and anti-PSP antibodies occur in an earlier stage than anti-Ro/La antibodies, and may identify a subset of primary Sjögren's syndrome patients with mild or incomplete disease, whereas anti-cofilin-1, anti- alpha-enolase and anti-RGI2 antibodies are potential biomarkers of MALT lymphoma. Antibody detection is also important to elucidate new aspects of SS pathophysiology, and in the future to permit a phenotype-specific patient approach. Herein we review the literature regarding new autoantibodies in SS and attempt to dissect their usefulness as diagnostic tools, pathogenic role, identification of clinical phenotypes and as predictors of an overlap syndrome.

Prevalence of Novel Candidate Sjogren Syndrome Autoantibodies in the Dry Eye Assessment and Management (DREAM) Study

PURPOSE

To evaluate the prevalence of novel candidate Sjogren syndrome (SS) autoantibodies [salivary protein-1 (SP-1), parotid secretory protein, carbonic anhydrase 6] in the DRy Eye Assessment and Management (DREAM) cohort, a study evaluating the effectiveness of omega-3 fatty acid supplements for the treatment of dry eye.

METHODS

Participants underwent ocular surface examinations and serological testing for traditional and novel SS autoantibodies. Dry eye assessment and management participants were categorized into the following 3 groups: 1) no history of SS or other autoimmune diseases and negative traditional SS autoantibodies (n = 352); 2) no history of SS but a history of other autoimmune diseases (n = 66); and 3) those who met the 2012 American College of Rheumatology SS classification criteria (n = 52).

RESULTS

Eleven percent had a history of SS, and 6% of those without a history of SS most likely had undiagnosed SS. The SS group had a higher prevalence of SP-1 autoantibodies than the group without SS or other autoimmune diseases (33% vs. 19%; P = 0.02) but had no difference in carbonic anhydrase 6 (P = 0.31) or parotid secretory protein autoantibodies (P = 0.33). Participants who were positive for the traditional autoantibodies alone or positive for both traditional and novel autoantibodies had the highest scores for corneal (P = 0.002) and conjunctival staining (P < 0.001).

CONCLUSIONS

Data from this multicenter, prospective study demonstrated that one of the novel candidate autoantibodies, SP-1, is associated with underlying SS and that novel autoantibodies may be associated with worse ocular surface disease. Future longitudinal studies are needed to evaluate their utility in screening patients with dry eye for SS.

MicroRNA in Sjögren's Syndrome: Their Potential Roles in Pathogenesis and Diagnosis

Sjögren's syndrome (SS) or sicca syndrome was described by Swedish ophthalmologist Sjögren in the year 1933 for the first time. The etiology of the SS is multifunctional and includes a combination of genetic predisposition and environmental as well as epigenetic factors. It is an autoimmune disease characterized by features of systemic autoimmunity, dysfunction, and inflammation in the exocrine glands (mainly salivary and lacrimal glands) and lymphocytic infiltration of exocrine glands. In fact, the involvement of lacrimal and salivary glands results in the typical features of dry eye and salivary dysfunction (xerostomia). Only in one-third of the patients also present systemic extraglandular manifestations. T cells were originally considered to play the initiating role in the autoimmune process, while B cells were restricted to autoantibody production. In recent years, it is understood that the roles of B cells are multiple. Moreover, autoantibodies and blood B cell analysis are major contributors to a clinical diagnosis of Sjögren's syndrome. Recently, there has been rising interest in microRNA implication in autoimmunity. Unfortunately, to date, there are only a few studies that have investigated their participation in SS etiopathogenesis. The purpose of this work is to gather the data present in the literature to clarify this complex topic.