Sjögren's syndrome: why autoimmune epithelitis?

Immortalized Human Conjunctival Epithelial Cells Produce Functional Complement C3 and C4 Proteins

PURPOSE

The aim of this study was to assess whether complement proteins C3 and C4 are produced by immortalized human conjunctival epithelial (HCjE) cells.

METHODS

Supernatants and cell lysates from undifferentiated and differentiated HCjE cells were assayed for C3 and C4 by enzyme-linked immunosorbent assay. To measure complement protein function, supernatants and lysates were treated with heat-aggregated IgG, and soluble C5b-9 was measured.

RESULTS

C3 was upregulated in supernatants from differentiated HCjE cells compared with undifferentiated HCjE cells (556.55 ± 91.75 vs. 56.95 ± 12.09 ng/mL, P <0.001). C4 was also increased in supernatants but to a much lesser extent (0.599 ± 0.476 vs. 0.172 ± 0.0133 ng/mL, P = 0.03). From HCjE cell lysates, total C3 production was 9.03 times higher in differentiated HCjE cells ( P <0.001), whereas total C4 remained relatively unchanged. After activation with heat-aggregated IgG, sC5b-9 could be detected from both undifferentiated and differentiated HCjE cell lysates, but not in the HCjE supernatants.

CONCLUSIONS

HCjE cells produce C3 and C4 in sufficient quantities to support the formation of sC5b-9, confirming their biological activity and suggesting that HCjE cells likely produce all complement proteins C1 through C9.

The Role of Major Salivary Gland Ultrasound in the Diagnostic Workup of Sicca Syndrome: A Large Single-Centre Study

(1) Objective: To determine the diagnostic accuracy of major salivary gland ultrasonography (SGUS) in primary Sjogren's syndrome (SS), we used the Outcome Measures in Rheumatology Clinical Trials (OMERACT) scoring system on a large single-centre cohort of patients with sicca syndrome. (2) Method: We retrospectively collected the clinical, imaging and serological data of all the patients referred with a suspicion of SS who underwent SGUS and minor salivary glands biopsy. (3) Results: A total of 132 patients were included. The SGUS scores were correlated between the two sides (p < 0.001). The diagnostic cut-off for SS (AUROC: 0.7408) was 6 for the SGUS-global sum (sensitivity: 32.43%; specificity: 96.84%). The cut-off with the highest specificity for SS diagnosis was 7. In the patients with a final diagnosis of SS, the mean SGUS score was significantly higher (p < 0.001) than that of the non-SS patients (3.73 vs. 1.32 for the SGUS-global sum). A significant correlation was demonstrated between the SGUS scores and final SS diagnosis (p < 0.001), biopsy positivity (p < 0.001), ANA positivity (p = 0.016), Ro-SSA positivity (p = 0.01), and gland fibrosis (p = 0.02). (4) Conclusions: SGUS, using the OMERACT scoring system, has moderate sensitivity and high specificity for the diagnosis of SS. The scoring showed a strong and direct correlation with all the clinical hallmarks of SS diagnosis, such as the positivity of a labial salivary gland biopsy, ANA and Ro-SSA statuses, and salivary gland fibrosis. Because of its high specificity, a SGUS-global score > 6 could be therefore employed for the diagnosis of SS in the case of ANA negativity or the unavailability of a biopsy.

Unsolved mystery of Fas: mononuclear cells may have trouble dying in patients with Sjögren's syndrome

BACKGROUND

Patients with Sjögren's syndrome, like other patients with autoimmune disorders, display dysregulation in the function of their immune system. Fas and Fas Ligand (FasL) are among the dysregulated proteins.

METHODS

We studied Fas and FasL on IL-2Rα+ cells and in serum of patients with Sjögren's syndrome (n = 16) and healthy individuals (n = 16); both from same ethnic and geographical background. We used flow cytometry and enzyme-linked immunosorbent for this purpose. We also measured the expression of Bcl-2 and Bax by reverse transcription quantitative real-time PCR (RT-qPCR) and percentage of apoptotic and dead cells using Annexin V and 7-AAD staining in lymphocytes.

RESULTS

FasL was increased in patients' T and B cells while Fas was increased in patients' monocytes, T and B cells. No signs of increased apoptosis were found. sFas and sFasL in patients' serum were increased, although the increase in sFasL was not significant. We suspect an effect of non-steroidal anti-inflammatory therapy on B cells, explaining the decrease of the percentage Fas+ B cells found within our samples. In healthy individuals, there was a noticeable pattern in the expression of FasL which mutually correlated to populations of mononuclear cells; this correlation was absent in the patients with Sjögren's syndrome.

CONCLUSIONS

Mononuclear cells expressing IL-2Rα+ had upregulated Fas in Sjögren's syndrome. However, the rate of apoptosis based on Annexin V staining and the Bcl-2/Bax expression was not observed in mononuclear cells. We suspect a functional role of abnormal levels of Fas and FasL which has not been cleared yet.

Analysis of PTPN22 -1123 G>C, +788 G>A and +1858 C>T Polymorphisms in Patients with Primary Sjögren's Syndrome

BACKGROUND

Primary Sjögren's syndrome (pSS) is an autoimmune exocrinopathy characterized by lymphocytic infiltration, glandular dysfunction and systemic manifestations. Lyp protein is a negative regulator of the T cell receptor encoded by the tyrosine phosphatase nonreceptor-type 22 (PTPN22) gene. Multiple single-nucleotide polymorphisms (SNPs) in the PTPN22 gene have been associated with susceptibility to autoimmune diseases. This study aimed to investigate the association of PTPN22 SNPs rs2488457 (-1123 G>C), rs33996649 (+788 G>A), rs2476601 (+1858 C>T) with pSS susceptibility in Mexican mestizo subjects.

METHODS

One hundred fifty pSS patients and 180 healthy controls (HCs) were included. Genotypes of PTPN22 SNPs were identified by PCR-RFLP. PTPN22 expression was evaluated through RT-PCR analysis. Serum anti-SSA/Ro and anti-SSB/La levels were measured using an ELISA kit.

RESULTS

Allele and genotype frequencies for all SNPs studied were similar in both groups (p > 0.05). pSS patients showed 17-fold higher expression of PTNP22 than HCs, and mRNA levels correlated with SSDAI score (r² = 0.499, p = 0.008) and levels of anti-SSA/Ro and anti-SSB/La autoantibodies (r² = 0.200, p = 0.03 and r² = 0.175, p = 0.04, respectively). Positive anti-SSA/Ro pSS patients expressed higher PTPN22 mRNA levels (p = 0.008), with high focus scores by histopathology (p = 0.02). Moreover, PTPN22 expression had high diagnostic accuracy in pSS patients, with an AUC = 0.985.

CONCLUSIONS

Our findings demonstrate that the PTPN22 SNPs rs2488457 (-1123 G>C), rs33996649 (+788 G>A) and rs2476601 (+1858 C>T) are not associated with the disease susceptibility in the western Mexican population. Additionally, PTPN22 expression may be helpful as a diagnostic biomarker in pSS.

Not all autoantibodies are clinically relevant. Classic and novel autoantibodies in Sjögren’s syndrome: A critical review

Sjögren’s syndrome (SjS) is a heterogeneous systemic disease. The abnormal responses to La/SSB and Ro/SSA of both B-cells and T-cells are implicated as well as others, in the destruction of the epithelium of the exocrine glands, whose tissue characteristically shows a peri-epithelial lymphocytic infiltration that can vary from sicca syndrome to systemic disease and lymphoma. Despite the appearance of new autoantibodies, anti-Ro/SSA is still the only autoantibody included in the American College of Rheumatology/European League Against Rheumatism (ACR/EULAR) classification criteria and is used extensively as a traditional biomarker in clinical practice. The study and findings of new autoantibodies in SjS has risen in the previous decade, with a central role given to diagnosis and elucidating new aspects of SjS physiopathology, while raising the opportunity to establish clinical phenotypes with the goal of predicting long-term complications. In this paper, we critically review the classic and the novel autoantibodies in SjS, analyzing the methods employed for detection, the pathogenic role and the wide spectrum of clinical phenotypes.

Regulation of MMP9 transcription by ETS1 in immortalized salivary gland epithelial cells of patients with salivary hypofunction and primary Sjögren's syndrome

Primary Sjögren’s syndrome (pSS) patients exhibit enhanced degradation of the salivary epithelium initially through MMP9 overexpression. We assessed the expression of MMP9 and an associated transcription factor, ETS1, in primary salivary gland epithelial cells (SGECs) and investigated potential regulatory mechanism(s) in immortalized SGECs. SGECs and iSGECs were derived from pSS and/or xerostomic “sicca” patients. siRNA knockdown of ETS1 in iSGECs was performed to determine MMP9 mRNA (qRT-PCR) and protein expression (ELISA). ETS1 binding to MMP9 promoter was assessed by luciferase activity and binding confirmed by mutagenesis and ChIP. Effects of ETS1 overexpression on progenitor and Epithelial-Mesenchymal transition (EMT) associated markers were determined by Western blot. Expression of ETS1 and its phosphorylated form in iSGECs was determined by immunofluorescence microscopy. ETS1 and MMP9 were overexpressed in SGECs of pSS and non-pSS sicca patients with salivary gland lymphocytic infiltration compared to non-pSS sicca patients without infiltration. ETS1 siRNA knockdown reduced both MMP9 mRNA and protein levels. ETS1 overexpression affected the expression of EMT and progenitor cell markers. Lastly, ETS1 bound the MMP9 promoter within the DNA region of −296 bp to −339 bp. ETS1 may impair salivary function through direct transcriptional control of the MMP9 promoter. ETS1 upregulation may also affect other factors involved in repair of the dysfunctional pSS salivary epithelium.

Renal Involvement in Primary Sjogren's Syndrome: A Case Series of Three Cases with Various Clinicopathological Presentations

Sjogren's syndrome is a prevalent and underdiagnosed systemic disease that primarily affects epithelial tissue. It may affect renal function, either as an epithelial disease causing tubulointerstitial nephritis (TIN) or as an immune complex-mediated glomerulopathy. These lesions may cause a variety of clinical features, both overt and occult. The epithelial disease is mediated by B and T cells. The prevalence of renal involvement in primary Sjogren's syndrome has been reported to range approximately from 10% to 30%. Patients with renal involvement in primary Sjogren's syndrome may have renal manifestations, such as renal tubular acidosis (RTA) Type I, TIN, diabetes insipidus, nephrolithiasis, and Fanconi syndrome. Distal RTA was reported more commonly than proximal RTA, which can present as acute hypokalemic paralysis. We present three cases of primary Sjogren's syndrome with significant renal involvement and various clinicopathological presentations.

E-Cadherin Signaling in Salivary Gland Development and Autoimmunity

E-cadherin, the major epithelial cadherin, is located in regions of cell–cell contact known as adherens junctions. E-cadherin contributes to the maintenance of the epithelial integrity through homophylic interaction; the cytoplasmic tail of E-cadherin directly binds catenins, forming a dynamic complex that regulates several intracellular signal transduction pathways, including epithelial-to-mesenchymal transition (EMT). Recent progress uncovered a novel and critical role for this adhesion molecule in salivary gland (SG) development and in SG diseases. We summarize the structure and regulation of the E-cadherin gene and transcript in view of the role of this remarkable protein in SG morphogenesis, focusing, in the second part of the review, on altered E-cadherin expression in EMT-mediated SG autoimmunity.

Ultrasound-guided core needle biopsy compared with open biopsy: a new diagnostic approach to salivary gland enlargement in Sjögren's syndrome?

OBJECTIVE

Persistent (≥2 months) major salivary gland enlargement in primary SS (pSS) patients is a well-known sign of possible involvement by B cell lymphoma. The study aimed to evaluate the diagnostic accuracy and safety of US-guided core needle biopsy (CNB) of major salivary glands compared with open surgical biopsy.

METHODS

Prospective pSS patients (cases) with clinically persistent salivary gland enlargement underwent US-guided CNB and were compared with retrospective pSS patients (controls) submitted to open surgical biopsy. The features analysed were pre-biopsy clinical and laboratory findings, adequacy of the material for histology and diagnostic-rendered and biopsy-related complications (reported by the patient with a questionnaire and clinically verified).

RESULTS

Thirteen cases underwent US-guided CNB: in nine, biopsy was performed on the parotid gland and in four it was performed on the submandibular gland. Sufficient material was obtained for pathological diagnosis in all samples. The final diagnoses were 5 (38.5%) B cell lymphoma, 1 (7.7%) lymphoepithelial sialadenitis, 4 (30.7%) other sialadenitis (granulomatous consistent with sarcoidosis, IgG4-related disease, chronic sclerosing, diffuse chronic) and 3/13 (23.1%) miscellaneous lesions. Thirteen controls underwent open surgical biopsy of the parotid. In one, inadequate material was obtained, while in 12 (92.3%) the pathologic diagnoses were 4 (33.3%) B cell lymphoma, 2 (16.7%) lymphoepithelial sialadenitis, 4 (33.3%) uncertain lymphoproliferative lesions and 2 (16.7%) miscellaneous lesions. Six cases (46.1%) reported six transient complications and 12/13 (92.3%) controls had 2 persistent and 14 transient complications.

CONCLUSION

US-guided CNB represents a novel, clinically relevant and safe approach for the management of pSS patients with parotid or submandibular persistent enlargement.

Association between EBV serological patterns and lymphocytic profile of SjS patients support a virally triggered autoimmune epithelitis

Sjögren's syndrome (SjS) is characterized by lymphocytic infiltration of exocrine glands, i.e. autoimmune epithelitis. Lymphocytes are central in SjS pathogenesis, with B-cell hyperactivity mediated by T-cells. B-cells are main targets of Epstein-Barr virus (EBV) infection, a frequently-suggested trigger for SjS. We aimed to evaluate how the EBV infection modulates B and T-cell subsets in SjS, including as controls Rheumatoid arthritis patients (RA) and healthy participants (HC). SjS patients presented decreased CXCR5⁺T-cells, although IL21-secreting Tfh and Tfc cells were increased. Tfc were positively correlated with ESSDAI scores, suggesting their relevant role in SjS pathogenesis. As previously described, SjS patients showed expanded circulating naïve B-cell compartments. SjS patients had a higher incidence of EBV-EA-D-IgG⁺ antibodies, characteristic of recent EBV-infection/reactivation. SjS patients with past infection or recent infection/reactivation showed increased CXCR3⁺Th1 and CXCR3⁺Tfh1 cells compared to those without active infection. SjS patients with a recent infection/reactivation profile presented increased transitional B-cells compared to patients with past infection and increased plasmablasts, compared to those without infection. Our results suggest EBV-infection contributes to B and T-cell differentiation towards the effector phenotypes typical of SjS. Local lymphocyte activation at ectopic germinal centres, mediated by Tfh and Tfc, can be EBV-driven, perpetuating autoimmune epithelitis, which leads to gland destruction in SjS.

New frontiers in precision medicine for Sjogren's syndrome

Introduction: Sjögren's syndrome is a unique systemic autoimmune disease, placed in the center of systemic autoimmunity and at the crossroads of autoimmunity and lymphoproliferation. The diverse clinical picture of the disease, the inefficacy of current biologic treatments, and the co-existence with lymphoma conferring to the patients' morbidity and mortality force the scientific community to review disease pathogenesis and reveal the major implicated cellular and molecular elements.Areas covered: Biomarkers for early diagnosis, prediction, stratification, monitoring, and targeted treatments can serve as a tool to interlink and switch from the clinical phenotyping of the disease into a more sophisticated classification based on the underlying critical molecular pathways and endotypes. Such a transition may define the establishment of the so-called precision medicine era in which patients' management will be based on grouping according to pathogenetically related biomarkers. In the current work, literature on Sjogren's syndrome covering several research fields including clinical, translational, and basic research has been reviewed.Expert opinion: The perspectives of clinical and translational research are anticipated to define phenotypic clustering of high-risk pSS patients and link the clinical picture of the disease with fundamental molecular mechanisms and molecules implicated in pathogenesis.

Pathophysiologic role of Interleukin-33/ST2 in Sjögren's syndrome

Interleukin-33 (IL-33) is a member of the IL-1 family and has dual functions as a nuclear factor as well as a cytokine. The pivotal role of IL-33 as an active player contributing to aberrant local and systemic damage has been highlighted in several inflammatory and autoimmune diseases. Primary Sjögren's syndrome (pSS) is an autoimmune disease characterized by dry eyes and mouth syndrome due to local dysfunctions of exocrine glands, but also accompanied with systemic manifestations. The pathophysiology of pSS has been advocated as a conjecture of activated B and T cells as well as the production of inflammatory cytokines and autoantibodies, driving epithelial tissue damage and disease progression. In pSS, IL-33 is released in the extracellular space from damaged salivary cells upon pro-inflammatory stimuli and/or dysfunction of epithelial barrier. Counter-regulatory mechanisms are initiated to limit the pro-inflammatory actions of IL-33 as portrayed by an increase in the decoy receptor for IL-33, the soluble form of ST2 (sST2). In pSS and associated diseases, the levels of IL-33 are significantly elevated in the serum or tears of patients. Mechanistically, IL-33 acts in synergy with IL-12 and IL-23 on NK and NKT cells to boost the production of IFN-γ contributing to inflammation. TNF-α, IL-1β and IFN-γ in turn further increase the activation of IL-33/ST2 pathway, thereby constituting a vicious inflammatory loop leading to disease exacerbation. IL-33/ST2 axis is involved in Sjögren's syndrome and opens new perspectives as therapeutic target of one of the culprits in the inflammatory perpetuation.

Proteomics-based analysis indicating α-enolase as a potential biomarker in primary Sjögren's syndrome

Background

Primary Sjögren's syndrome (pSS) is a chronic autoimmune disease. Its etiology is not well understood. Salivary glands are the main target organ in pSS, investigating the changes of salivary protein in pSS patients may not only be a valuable way of identifying new biomarkers/antigens for pSS, but also of revealing the pathogenesis underlying this autoimmune disease. In the present study, we aimed to investigate new biomarkers and explore their potential role in pSS.

Methods

In this study, α-enolase (ENO1) was found to be overexpressed in pSS by 1D gel electrophoresis/mass spectrometry. The finding was verified by Western blots, immunohistochemistry (IHC), and polymerase chain reaction (PCR) results in both saliva and labial salivary glands. The expression level of immunoglobulin G (IgG) antibody to ENO1 was then tested by enzyme-linked immunosorbent assay (ELISA).

Results

ENO1 autoantibody was found to be overexpressed in pSS compared with healthy controls. The effects of ENO1 overexpression on rat submandibular gland cell line SMG-C6 was investigated in vitro. The expressions of proteins related to saliva secretion and immunomodulatory were upregulated in ENO1 overexpressed SMG-C6 cells.

Conclusions

Both ENO1 and anti-ENO1 autoantibody are overexpressed in pSS patients. Nevertheless, their potential role in the pathogenesis of pSS warrants further study.

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.

P2 Receptors as Therapeutic Targets in the Salivary Gland: From Physiology to Dysfunction

Although often overlooked in our daily lives, saliva performs a host of necessary physiological functions, including lubricating and protecting the oral cavity, facilitating taste sensation and digestion and maintaining tooth enamel. Therefore, salivary gland dysfunction and hyposalivation, often resulting from pathogenesis of the autoimmune disease Sjögren's syndrome or from radiotherapy of the head and neck region during cancer treatment, severely reduce the quality of life of afflicted patients and can lead to dental caries, periodontitis, digestive disorders, loss of taste and difficulty speaking. Since their initial discovery in the 1970s, P2 purinergic receptors for extracellular nucleotides, including ATP-gated ion channel P2X and G protein-coupled P2Y receptors, have been shown to mediate physiological processes in numerous tissues, including the salivary glands where P2 receptors represent a link between canonical and non-canonical saliva secretion. Additionally, extracellular nucleotides released during periods of cellular stress and inflammation act as a tissue alarmin to coordinate immunological and tissue repair responses through P2 receptor activation. Accordingly, P2 receptors have gained widespread clinical interest with agonists and antagonists either currently undergoing clinical trials or already approved for human use. Here, we review the contributions of P2 receptors to salivary gland function and describe their role in salivary gland dysfunction. We further consider their potential as therapeutic targets to promote physiological saliva flow, prevent salivary gland inflammation and enhance tissue regeneration.

Unusual Presentation of Polyautoimmunity and Renal Tubular Acidosis in an Adolescent With Hashimoto's Thyroiditis and Central Pontine Myelinolysis

Background: Hashimoto's thyroiditis is frequently associated with other autoimmune diseases and may include renal involvement. Case description: A 17-year-old female with previously diagnosed Hashimoto's thyroiditis and vitiligo was admitted to a pediatric intensive care unit with hypokalemic paralysis and acidosis, after having suffered from recurrent muscular weakness for approximately one year. A few days later she developed central pontine myelinolysis. After initial stabilization she was also diagnosed with distal renal tubular acidosis (dRTA) and tubular proteinuria which can occur in Sjögren's syndrome. Extended screening for autoimmune diseases additionally revealed celiac disease. Treatment with Prednisone and substitution of potassium quickly lead to the resolution of proteinuria and dRTA, but unilateral paralysis of the sixth nerve as a result of central pontine myelinolysis was irreversible. Conclusions: This is the rare case of polyautoimmunity including autoimmune thyroiditis, Sjögren's syndrome, vitiligo and celiac disease in an adolescent with few disease-specific symptoms. The diagnoses were made via a complicating nephritis causing dRTA and proteinuria. Delay in diagnosis lead to permanent neurological damage. This case highlights the need for pediatricians to be aware of rare accompanying diseases and their complications in "common" pediatric autoimmune diseases like Hashimoto's thyroiditis and celiac disease.

Mesenchymal Stem Cells Extract (MSCsE)-Based Therapy Alleviates Xerostomia and Keratoconjunctivitis Sicca in Sjogren's Syndrome-Like Disease

Sjogren’s syndrome (SS) is an autoimmune disease that manifests primarily in salivary and lacrimal glands leading to dry mouth and eyes. Unfortunately, there is no cure for SS due to its complex etiopathogenesis. Mesenchymal stem cells (MSCs) were successfully tested for SS, but some risks and limitations remained for their clinical use. This study combined cell- and biologic-based therapies by utilizing the MSCs extract (MSCsE) to treat SS-like disease in NOD mice. We found that MSCsE and MSCs therapies were successful and comparable in preserving salivary and lacrimal glands function in NOD mice when compared to control group. Cells positive for AQP5, AQP4, α-SMA, CK5, and c-Kit were preserved. Gene expression of AQP5, EGF, FGF2, BMP7, LYZ1 and IL-10 were upregulated, and downregulated for TNF-α, TGF-β1, MMP2, CASP3, and IL-1β. The proliferation rate of the glands and serum levels of EGF were also higher. Cornea integrity and epithelial thickness were maintained due to tear flow rate preservation. Peripheral tolerance was re-established, as indicated by lower lymphocytic infiltration and anti-SS-A antibodies, less BAFF secretion, higher serum IL-10 levels and FoxP3⁺ T_reg cells, and selective inhibition of B220⁺ B cells. These promising results opened new venues for a safer and more convenient combined biologic- and cell-based therapy.

Berunda Polypeptides: Biheaded Rapamycin Carriers for Subcutaneous Treatment of Autoimmune Dry Eye Disease

The USFDA-approved immunosuppressive drug rapamycin (Rapa), despite its potency, is limited by poor bioavailability and a narrow therapeutic index. In this study, we sought to improve bioavailability of Rapa with subcutaneous (SC) administration and to test its therapeutic feasibility and practicality in a murine model of Sjögren's syndrome (SS), a systemic autoimmune disease with no approved therapies. To improve its therapeutic index, we formulated Rapa with a carrier termed FAF, a fusion of the human cytosolic FK506-binding protein 12 (FKBP12) and an elastin-like polypeptide (ELP). The resulting 97 kDa FAF (i) has minimal burst release, (ii) is "humanized", (iii) is biodegradable, (iv) solubilizes two Rapa per FAF, and (v) avoids organic solvents or amphiphilic carriers. Demonstrating high stability, FAF remained soluble and monodisperse with a hydrodynamic radius of 8 nm at physiological temperature. A complete pharmacokinetic (PK) analysis of FAF revealed that the bioavailability of SC FAF was 60%, with significantly higher blood concentration during the elimination phase compared to IV FAF. The plasma concentration of Rapa delivered by FAF was 8-fold higher with a significantly increased plasma-to-whole blood ratio relative to free Rapa, 24 h after injection. To evaluate therapeutic effects, FAF-Rapa was administered SC every other day for 2 weeks to male non-obese diabetic (NOD) mice, which develop an SS-like autoimmune-mediated lacrimal gland (LG) inflammation and other characteristic features of SS. Both FAF-Rapa and free Rapa exhibited immunomodulatory effects by significantly suppressing lymphocytic infiltration, gene expression of IFN-γ, MHC II, type I collagen and IL-12a, and cathepsin S (CTSS) activity in LG compared to controls. Serum chemistry and histopathological analyses in major organs revealed no apparent toxicity of FAF-Rapa. Given its improved PK and equipotent therapeutic efficacy compared to free Rapa, FAF-Rapa is of further interest for systemic treatments for autoimmune diseases like SS.

The role of stroma and epithelial cells in primary Sjögren's syndrome

Primary SS (pSS) is a chronic autoimmune condition characterized by infiltration of the exocrine glands and systemic B cell hyperactivation. This glandular infiltration is associated with loss of glandular function, with pSS patients primarily presenting with severe dryness of the eyes and mouth. Within the affected glands, the infiltrating lymphocytes are organized in tertiary lymphoid structures. Tertiary lymphoid structures subvert normal tissue architecture and impact on organ function, by promoting the activation and maintenance of autoreactive lymphocytes. This review summarizes the current knowledge about the role of stromal cells (including endothelium, epithelium, nerves and fibroblasts) in the pathogenesis of pSS, in particular the interactions taking place between stromal cells and infiltrating lymphocytes. We will provide evidences pointing towards the driving role of stromal cells in the orchestration of the local inflammatory milieu, thus highlighting the need for therapies aimed at targeting this compartment alongside classical immunosuppression in pSS.

Involvement of Aquaporins in the Pathogenesis, Diagnosis and Treatment of Sjögren's Syndrome

Sjögren’s syndrome (SS) is a chronic autoimmune disease characterized by lymphocytic infiltration of salivary and lacrimal glands resulting in diminished production of saliva and tears. The pathophysiology of SS has not yet been fully deciphered. Classically it has been postulated that sicca symptoms in SS patients are a double step process whereby lymphocytic infiltration of lacrimal and salivary glands (SG) is followed by epithelial cell destruction resulting in keratoconjunctivitis sicca and xerostomia. Recent advances in the field of the pathophysiology of SS have brought in new players, such as aquaporins (AQPs) and anti AQPs autoantibodies that could explain underlying mechanistic processes and unveil new pathophysiological pathways offering a deeper understanding of the disease. In this review, we delineate the link between the AQP and SS, focusing on salivary glands, and discuss the role of AQPs in the treatment of SS-induced xerostomia.

The Cutaneous Spectrum of Lupus Erythematosus

Systemic lupus erythematosus is a complex autoimmune disease with a wide spectrum of clinical and immunopathological features. Cutaneous and articular manifestations are the most common signs in patients with systemic lupus erythematosus. We here review the pathogenesis and the new classification of cutaneous lupus erythemathosus with a discussion of the significance of the various cutaneous signs. The lesions are classified according to the level of the cellular infiltrate and tissue damage in the epidermis, dermis, and/or subcutis. Furthermore, cutaneous lesions pointing to the presence of a thrombotic vasculopathy and those due to a distinct inflammatory, neutrophilic-mediated reaction pattern are highlighted. Particular attention will be given in describing the histology of skin manifestation. Treatment options for cutaneous lupus erythemathosus have increased with the introduction of new biological therapies. However, the majority of the patients still benefit from antimalarials, which remain the cornerstone of treatment. The evaluation and management of cutaneous lupus erythemathosus patients depend on the clinical findings and associated symptoms.

Gene Therapy of Salivary Diseases

For many years, our research group worked to develop gene transfer approaches for salivary gland disorders that lacked effective conventional therapy. The purpose of this chapter is to describe and update key methods used in this process. As described in our original chapter from the 2010 volume, we focus on one clinical condition, irradiation-induced salivary hypofunction, and address the choice of transgene and vector to be used, the construction of recombinant viral vectors, how vector delivery is accomplished, and methods for assessing vector function in vitro and in an appropriate animal model.

TLR2 signals via NF-κB to drive IL-15 production in salivary gland epithelial cells derived from patients with primary Sjögren's syndrome

Toll-like receptors (TLRs) are pattern recognition receptors linking innate and adaptive immune responses, which resulted overexpressed in primary Sjögren's syndrome (pSS). Interleukin-15 (IL-15) is a pro-inflammatory cytokine which was recently demonstrated to be involved in pSS pathogenesis. The study was undertaken to clarify whether TLR2 is involved in the production of IL-15 in human salivary gland epithelial cells (SGEC) from pSS patients. SGEC primary cell cultures were established from pSS minor salivary gland tissues explanted from patients with a sure diagnosis of SS. After neutralization of TLR2 with a blocking monoclonal antibody, IL-15 production was assayed by immunoblotting and flow cytometry, IL-15 in the culture supernatants was measured by ELISA, and mRNA levels were assessed by RT-PCR and real-time PCR. The production of IL-15 by pSS SGEC decreased in culture supernatants and in protein lysates (p < 0.01) when TLR2 signaling was inhibited in pSS SGEC. In addition, a control at the transcriptional level was also detected; in fact, inhibition of nuclear factor (NF)-κB through the transfection of pSS SGEC with the dominant-negative inhibitory κBα proteins (IκBα) vector (IκBαDN) abrogated the stimulatory effect of TLR2 on IL-15 production. These data suggest that TLR2 activation is involved in the induction of IL-15 production by pSS SGEC and promotes inflammation through NF-κB activation. Therefore, therapeutic strategies that target TLR2/IL-15 pathway might be strong candidates for preventing or treating pSS.

Mouse Models of Primary Sjogren's Syndrome

Sjogren's syndrome (SjS) is a chronic autoimmune disorder characterized by immune cell infiltration and progressive injury to the salivary and lacrimal glands. As a consequence, patients with SjS develop xerostomia (dry mouth) and keratoconjunctivitis sicca (dry eyes). SjS is the third most common rheumatic autoimmune disorder, affecting 4 million Americans with over 90% of patients being female. Current diagnostic criteria for SjS frequently utilize histological examinations of minor salivary glands for immune cell foci, serology for autoantibodies, and dry eye evaluation by corneal or conjunctival staining. SjS can be classified as primary or secondary SjS, depending on whether it occurs alone or in association with other systemic rheumatic conditions, respectively. Clinical manifestations typically become apparent when the disease is relatively advanced in SjS patients, which poses a challenge for early diagnosis and treatment of SjS. Therefore, SjS mouse models, because of their close resemblance to the human SjS, have been extremely valuable to identify early disease markers and to investigate underlying biological and immunological dysregulations. However, it is important to bear in mind that no single mouse model has duplicated all aspects of SjS pathogenesis and clinical features, mainly due to the multifactorial etiology of SjS that includes numerous susceptibility genes and environmental factors. As such, various mouse models have been developed in the field to try to recapitulate SjS. In this review, we focus on recent mouse models of primary SjS xerostomia and describe them under three categories of spontaneous, genetically engineered, and experimentally induced models. In addition, we discuss future perspectives highlighting pros and cons of utilizing mouse models and current demands for improved models.

Growth Arrest-Specific 6 Protein in Patients with Sjögren Syndrome: Determination of the Plasma Level and Expression in the Labial Salivary Gland

Aims

Growth arrest-specific protein 6 (Gas6) is a vitamin K-dependent protein expressed by endothelial cells and leukocytes that are involved in cell survival, migration, and proliferation in response to inflammatory processes. The aim of this study was to assess the implications of Gas6 in Sjögren syndrome (SS) and its expression in the labial salivary gland.

Methods and Results

A total of 254 adults, including 159 with primary Sjögren syndrome (pSS), 34 with secondary Sjögren syndrome (sSS), and 61 normal controls, were recruited. Plasma Gas6 concentrations were determined, and Gas6 expressions in labial salivary gland (LSG) tissues from controls and pSS and sSS patients were also evaluated. Plasma Gas6 concentrations were significantly lower among patients with pSS than normal controls (13.5 ± 8.6 vs. 19.9 ± 13.4 ng/ml, p < 0.001). There were, however, no significant differences in plasma Gas6 levels between pSS and sSS patients (13.5 ± 8.6 vs. 16.9 ± 11.2 ng/ml, p = 0.068). In multivariate logistic regression analysis, after adjustment for white blood cell count, hemoglobin level, platelet count, lymphocyte count, and C3 and C4 levels, lower plasma Gas6 concentrations were significantly associated with an increased risk of SS. Moreover, by using a semi-quantitative scale to evaluate Gas6 expression in LSG tissues, Gas6 expression was found to be markedly lower in LSG tissues from pSS patients than in tissues from normal controls.

Conclusions

Decreased plasma Gas6 concentration and LSG expression were associated with pSS. As such, Gas6 may represent a novel independent risk factor for pSS, with a potential role in salivary gland inflammation and dysfunction.

Renal involvement in primary Sjögren's syndrome

SS is a prevalent and underdiagnosed systemic disease that primarily affects epithelial tissue. It may affect renal function either as epithelial disease causing tubulointerstitial nephritis or as an immune complex-mediated glomerulopathy. These lesions may cause a variety of clinical features, both overt and occult. The epithelial disease is mediated by B and T cells, notably the Th17 subtype. We review the prevalence of renal SS, its presentation, likely pathogenesis and treatment.

Monocytes from Sjögren's syndrome patients display increased vasoactive intestinal peptide receptor 2 expression and impaired apoptotic cell phagocytosis

Sjögren's syndrome (SS) is a chronic autoimmune disease characterized by salivary and lacrimal gland dysfunction. Clinical observations and results from animal models of SS support the role of aberrant epithelial cell apoptosis and immune homeostasis loss in the glands as triggering factors for the autoimmune response. Vasoactive intestinal peptide (VIP) promotes potent anti-inflammatory effects in several inflammatory and autoimmune disease models, including the non-obese diabetic (NOD) mouse model of SS. With the knowledge that VIP modulates monocyte function through vasoactive intestinal peptide receptors (VPAC) and that immune homeostasis maintenance depends strongly upon a rapid and immunosuppressant apoptotic cell clearance by monocytes/macrophages, in this study we explored VPAC expression on monocytes from primary SS (pSS) patients and the ability of VIP to modulate apoptotic cell phagocytic function and cytokine profile. Monocytes isolated from individual pSS patients showed an increased expression of VPAC2 subtype of VIP receptors, absent in monocytes from control subjects, with no changes in VPAC1 expression. VPAC2 receptor expression could be induced further with lipopolysaccharide (LPS) in pSS monocytes and VIP inhibited the effect. Moreover, monocytes from pSS patients showed an impaired phagocytosis of apoptotic epithelial cells, as evidenced by reduced engulfment ability and the failure to promote an immunosuppressant cytokine profile. However, VIP neither modulated monocyte/macrophage phagocytic function nor did it reverse their inflammatory profile. We conclude that monocytes from pSS patients express high levels of VPAC2 and display a deficient clearance of apoptotic cells that is not modulated by VIP.

Tear cathepsin S as a candidate biomarker for Sjögren's syndrome

OBJECTIVE

The diagnosis of Sjögren's syndrome (SS) in routine practice is largely a clinical one and requires a high index of suspicion by the treating physician. This great dependence on clinical judgment frequently leads to delayed diagnosis or misdiagnosis. Tear protein profiles have been proposed as simple and reliable biomarkers for the diagnosis of SS. Given that cathepsin S activity is increased in the lacrimal glands and tears of NOD mice (a murine model of SS), the aim of this study was to explore the clinical utility of using tear cathepsin S (CTSS) activity as a biomarker for SS.

METHODS

A method to measure CTSS activity in tears eluted from Schirmer's test strips was developed and validated. Schirmer's tests were performed and CTSS activity measurements were obtained in 278 female subjects, including 73 with SS, 79 with rheumatoid arthritis, 40 with systemic lupus erythematosus, 10 with blepharitis, 31 with nonspecific dry eye disease, and 12 with other autoimmune diseases, as well as 33 healthy control subjects.

RESULTS

The median tear CTSS activity in patients with SS was 4.1-fold higher than that in patients with other autoimmune diseases, 2.1-fold higher than that in patients with nonspecific dry eye disease, and 41.1-fold higher than that in healthy control subjects. Tear CTSS levels were equally elevated in patients with primary SS and those with secondary SS, independent of the Schirmer's test strip values or the levels of circulating anti-SSA or anti-SSB antibodies.

CONCLUSION

Markedly high levels of tear CTSS activity are suggestive of SS. CTSS activity in tears can be measured in a simple, quick, economical, and noninvasive manner and may serve as a novel biomarker for autoimmune dacryoadenitis during the diagnostic evaluation for SS.

Hypokalemic paralysis as a presenting manifestation of primary Sjögren's syndrome accompanied by vitamin D deficiency

Primary Sjögren's syndrome (pSS) is a chronic autoimmune disease characterized by progressive lymphocyte infiltration of the exocrine glands. Overt or latent renal tubular acidosis (RTA) is a common extraglandular manifestation of pSS.Vitamin D deficiency is associated with autoimmune disorders; however, the potential correlation between pSS and vitamin D deficiency is rarely discussed. The current patient presented with distal RTA, hypocalcemia, and hypophosphatemia that were found to be secondary to both vitamin D deficiency and pSS. In patients diagnosed with both distal RTA and vitamin D deficiency, clinicians should consider autoimmune diseases such as pSS, as a possible underlying etiology.

Destruction of salivary and lacrimal glands by Th1-polarized reaction in a model of secondary Sjögren's syndrome in lupus-prone female NZB × NZWF(1) mice

T helper (Th)1/Th2 balance determines the direction of some kinds of autoimmune diseases. The involvement of acini areas by CD4(+) helper T(Th) cell subset in submandibular and lacrimal glands are largely unknown in secondary Sjögren's syndrome (sSjS) with systemic lupus erythematosus (SLE). Submandibular and lacrimal glands were examined immunopathologically in lupus-prone female NZB × NZW(B/W)F(1) mice, model for human sSjS with SLE. Dacryoadenitis and sialoadenitis with renal failure developed with age. Infiltration of lymphoid cells (lymphocytes and plasma cells) expanded from the periductal areas in striated ducts to the acini, and the isolated foci in the acini were observed in those organs. The destruction of duct and acini epithelium, including the myoepithelium, was induced by interferon (IFN)-γ(+) and IgG2a(+) lymphoid cells, but not by interleukin(IL)-4(+), IL-5(+), IL-13(+), and IgG1(+) lymphoid cells. Compared with IL-5 and IL-13, high values of IFN-γ were produced systemically at various ages. Also local expression of IFN-γ mRNA was higher than that of IL-4 mRNA. The result suggests that the acini destruction in submandibular and lacrimal glands may be induced by systemic and local Th1 cell dominant reactions in lupus-prone B/WF(1) mice with sSjS.

Subgroups of Sjögren syndrome patients according to serological profiles

Sjögren Syndrome (SS) is a systemic, autoimmune disorder characterized by lymphocytic infiltration of the exocrine glands. Different clinical associations have been described for each of the diverse autoantibodies found in SS patients. Antibodies directed against the Ro/La ribonucleoprotein complexes have been correlated with younger age, more severe dysfunction of the exocrine glands and a higher prevalence of extraglandular manifestations. Anti-nuclear antibodies and rheumatoid factors have been associated to extraglandular manifestations and an active immunological profile, while cryoglobulins are markers of more severe disease and correlate to lymphoma development and death. Antibodies to cyclic citrullinated peptides are scarce in SS and have been linked in some cases to the development of non-erosive arthritis. Furthermore, the presence of anti-mitochondrial antibodies and anti-smooth muscle antibodies in the sera of primary SS patients is considered indicative of primary biliary cirrhosis and autoimmune hepatitis, respectively. In addition, anti-centromere antibodies have been associated with a clinical phenotype intermediate between primary SS and systemic sclerosis, while antibodies against carbonic anhydrase have been related to renal tubular acidosis. Finally, an association of anti-muscarinic antibodies with cytopenias and a higher disease activity has also been described in primary SS. In conclusion, although not all of the above mentioned antibodies are useful for predicting distinct patient subgroups in SS, knowledge of the clinical associations of the different autoantibody specificities encountered in SS can advance our understanding of the disease and improve patient management.

TLR2 ligation induces the production of IL-23/IL-17 via IL-6, STAT3 and NF-kB pathway in patients with primary Sjogren's syndrome

INTRODUCTION

The study was undertaken to investigate the interrelation of toll-like receptor (TLR) and interleukin (IL)-17 in the salivary glands of patients with primary Sjogren's syndrome (pSS) and to determine the role of TLR and IL-17 in the pathophysiology of pSS.

METHODS

The expressions of various TLRs, IL-17 and the cytokines involved in Th17 cell differentiation including IL-6, IL-23, tumor necrosis factor-alpha (TNF-α) and IL-1β were examined by immunohistochemistry in salivary glands of pSS patients. The IL-17 producing CD4+ T cells (Th17 cells) were examined by flow cytometry and confocal staining in peripheral mononuclear blood cells (PMBCs) and salivary glands of pSS patients. After PBMCs were treated with TLR specific ligands, the induction of IL-17 and IL-23 was determined using real-time PCR and ELISA. The signaling pathway that mediates the TLR2 stimulated production of IL-17 and IL-23 was investigated by using treatment with specific signaling inhibitors.

RESULTS

We showed that TLR2, TLR4, TLR6, IL-17 and the cytokines associated with Th17 cells were highly expressed in salivary glands of pSS patients but not in controls. The expressions of TLR2, TLR4 and TLR6 were observed in the infiltrating mononuclear cells and ductal epithelial cells, whereas IL-17 was mainly observed in infiltrating CD4+ T cells. The number of IL-17 producing CD4+ T cells was significantly higher in pSS patients both in PBMCs and minor salivary glands. The stimulation of TLR2, TLR4 and TLR6 additively induced the production of IL-17 and IL-23 from the PBMCs of pSS patients especially in the presence of TLR2 stimulation. IL-6, signal transducer and activator of transcription 3 (STAT3) and nuclear factor-kappaB (NF-kB) pathways were implicated in the TLR2 stimulated IL-17 and IL-23.

CONCLUSIONS

Our data demonstrate that TLR2 ligation induces the production of IL-23/IL-17 via IL-6, STAT3 and NF-kB pathway in pSS. Therefore, therapeutic strategies that target TLR/IL-17 pathway might be strong candidates for treatment modalities of pSS.

Dysfunction of lacrimal and salivary glands in Sjögren's syndrome: nonimmunologic injury in preinflammatory phase and mouse model

Sjögren's syndrome (SjS) is a chronic autoimmune disorder characterized by dry eyes and dry mouth due to dacryoadenitis and sialoadenitis with SS-A/Ro and/or SS-B/La autoantibodies in genetically predisposed individuals. Destruction of lacrimal and salivary glands by autoimmune reactions may lead to clinical manifestation. However, the mechanisms behind the decreased volume of secretions in tears and saliva are complex and are not fully understood. Exocrine gland dysfunction may precede autoimmunity (acquired immunity) or represent a process independent from inflammation in the pathogenesis of SjS. The preceded functional and morphologic changes of those tissues by nonimmunologic injury before the development of inflammation at the sites of target organs have been implicated. This paper focuses on the several factors and components relating to glandular dysfunction and morphologic changes by nonimmunologic injury during the preinflammatory phase in mouse model, including the factors which link between innate immunity and adaptive immunity.

Therapeutic strategies for SLE involving cytokines: mechanism-oriented therapies especially IFN-gamma targeting gene therapy

Systemic lupus erythematosus (SLE: lupus) is a chronic complicated autoimmune disease and pathogenesis is still unclear. However, key cytokines have been recognized. Interferon (IFN)-γ and also IFNalpha/beta are of particular importance. Depending on the concept that lupus is a helper T(Th)1 disease and that dendritic cells (DCs) determine the direction of lupus, balance shift of Th1/Th2 and immunogenic/tolerogenic DCs is reviewed for therapy. (IFN)-gamma- and IFN-alpha/beta-targeted (gene) therapies are introduced. These consist of Th1/Th2 balance shift and elimination of IFN-gamma and IFN-gamma-related cytokines such as (interleukin)IL-12 and IL-18. Other approaches include suppression of immunocompetent cells, normalization of abnormal T-cell function, costimulation blockade, B lymphocyte stimulator (Blys) blockade, and suppression of nephritic kidney inflammation. Moreover, balance shift of IFN-alpha/beta and tumor necrosis factor (TNF)-alpha together with regulatory T(Treg) cells are briefly introduced. Clinical application will be discussed.

Evaluation of quality of life in relation to anxiety and depression in primary Sjögren's syndrome

The aim of this study was to evaluate health-related quality of life (HR-QOL) in patients with primary Sjögren's syndrome (pSS) using both Short-Form 36 (SF-36) and World Health Organization Quality of Life Assessment-BREF (WHOQOL-BREF) questionnaires and to determine the effects of anxiety and depression on HR-QOL using the Hospital Anxiety-Depression Scale (HADS). In this cross-sectional study, 107 female patients with pSS (mean age 54.10 ± 10.2 years), fulfilling US-European Consensus Criteria and 109 female controls (mean age 53.4 ± 10.9 years) were included. Student's t test, Mann-Whitney U test, and analysis of variance (ANOVA) were used for statistical analysis. P values > 0.05 were accepted as significant. All domains of the SF-36, with the exception of "Vitality", and all domains of the WHOQOL-BREF with the exception of "Environment", were significantly lower in pSS patients compared with healthy controls. In pSS patients having anxiety according to HADS, the scores of all domains of WHOQOL-BREF were significantly lower, and in patients having depression according to HADS, three of four domains of WHOQOL-BREF were significantly lower compared with the rest of the group. However, the scores of two domains of the SF-36, namely "Role-Physical" and "Role-Emotional" domains, were significantly higher in pSS patients having depression according to HADS. We confirmed the presence of impaired HR-QOL in pSS. Whereas the presence of anxiety and/or depression generally showed a negative affect on HR-QOL, interestingly, depression seemed to improve the scores of "Role-Physical" and "Role-Emotional" domains of the SF-36. This surprising finding might be related to adaptation to changing health. Social support based upon cultural traditions might also have contributed.

[Frequency of systemic manifestations in patients with primary Sjögren's syndrome in Argentina]

Twenty to 71% of patients with Sjögren's syndrome (SS) will develop systemic manifestations.

OBJECTIVE

To characterize the clinical-serological presentation and the frequency of systemic manifestations in patients with primary SS.

METHODS

Retrospective study including patients with SS visited in "Hospital Británico de Buenos Aires" during the period from January 2000 to August 2008.

RESULTS

Forty-one patients fulfilled the 2002 American-European classification criteria for SS. All patients were women. Mean age at enrollment was 57.85 ± 12.42 years (range 26-79). Mean duration of the disease was 9.28 years (range 0.08-24). Thirty-three (80.49%) developed systemic manifestations. The most frequent were arthritis, cutaneous vasculitis and polyneuropathy. This group featured more frequently ANA titles ≥ 1/640 and hypocomplementemia; although no statistical significance was found. The frequency of systemic manifestations found was greater than reported in the literature.

CONCLUSIONS

A multidisciplinary approach focusing also on systemic manifestations should be the new standard for management of SS.

Gene therapy of salivary diseases

For many years, our laboratory has been developing gene transfer approaches for salivary gland disorders that currently lack effective therapy. The purpose of this chapter is to describe key methods used in this developmental process. Specifically, we focus on one clinical condition, irradiation-induced salivary hypofunction, and address the choice of transgene and vector to be used, the construction of recombinant viral vectors, how vector delivery is accomplished, and methods for assessing vector function in vitro and in an appropriate animal model.