Discerning the kinetics of autoimmune manifestations in a model of Sjögren's syndrome

Ectopic follicles are non-encapsulated organized lymphoid structures that form at sites of inflammation and presumably contribute to the activation and differentiation of cells with autoreactive potential within target tissues. As such, directed targeting of ectopic follicles in settings of autoimmunity may provide a means to specifically inhibit the activation of autoreactive cells without impairing protective immune responses ongoing in peripheral lymphoid tissues. NOD·H2h4 mice are a non-diabetic strain of NOD mice which develop a Sjögren's syndrome-like disease which includes the formation of ectopic follicles in the salivary gland and characteristic Sjögren's autoantibodies. The goal of these studies was to better characterize the formation of ectopic follicles in this model and to explore their contribution to autoimmunity. Our studies show that by 8 weeks of age, young NOD·H2h4 mice spontaneously develop an abundance of splenic germinal centers, prior to the emergence of lymphocyte infiltration in the salivary gland tissue. Ectopic follicle formation in the salivary gland begins to appear in these mice between 12 and 16 weeks of age. Interestingly, anti-Ro and anti-La autoantibodies precede the development of ectopic follicles in young NOD·H2h4 mice. In contrast, production of anti-dsDNA antibodies is delayed and largely coincides with the formation of ectopic follicles in these mice. These data suggest that tertiary lymphoid structures may arise from the trafficking of activated T and B cells to sites of inflammation in non-lymphoid tissues. Furthermore, local presentation of autoantigens may then promote the expansion of autoreactive cells with specificities distinct from those generated in the splenic micro-environment.     

Sjögren's syndrome: Another facet of the autoimmune/inflammatory syndrome induced by adjuvants (ASIA)

Recently, a new syndrome, namely the “Autoimmune/inflammatory syndrome induced by adjuvants” (ASIA) has been defined. In this syndrome different conditions characterized by common signs and symptoms and induced by the presence of an adjuvant are included. The adjuvant is a substance capable of boosting the immune response and of acting as a trigger in the development of autoimmune diseases. Post-vaccination autoimmune phenomena represent a major issue of ASIA. Indeed, despite vaccines represent a mainstay in the improvement of human health, several of these have been implicated as a potential trigger for autoimmune diseases. Sjogren's Syndrome (SjS) is a systemic chronic autoimmune inflammatory disease characterized by the presence of an inflammatory involvement of exocrine glands accompanied by systemic manifestations. Own to the straight association between infectious agents exposure (mainly viruses) and sicca syndrome development, the possible link between vaccine and SjS is not surprising. Indeed, a few cases of SjS following vaccine delivery have been reported. At the same extent, the induction of SjS following silicone exposure has been described too. Thus, the aim of this review was to focus on SjS and its possible development following vaccine or silicone exposure in order to define another possible facet of the ASIA syndrome.     

Viral etiopathogenesis of Sjögren's syndrome: role of the hepatitis C virus

Patients with hepatitis C virus (HCV) chronic infection present some extrahepatic manifestations that may mimic the clinical, immunologic and histological manifestations of primary Sj?gren's syndrome (SS). Thus, HCV patients with sicca symptomatology and positive autoantibodies could be misdiagnosed as a 'primary' SS. Nevertheless, there are several clinical and immunologic features that could help us differentiate both processes.     

Primary biliary cirrhosis and Sjögren's syndrome: autoimmune epithelitis

Primary biliary cirrhosis (PBC) has been often coined a model autoimmune disease based on the homogeneity amongst patients, the frequency and similarity of antimitochondrial antibodies, including the highly directed immune response to pyruvate dehydrogenase (PDC-E2). A significant number of patients with PBC suffer from sicca and amongst these, there are patients who also have classic Sj?gren's syndrome. Indeed, both PBC and Sj?gren's syndrome are characterized by inflammation of target epithelial elements. Both diseases can be considered on the basis of a number of other related clinical aspects, including proposed unique apoptotic features of the target tissue, the role of secretory IgA, and the frequency with which both diseases overlap with each other. Indeed, PBC may be considered a Sj?gren's syndrome of the liver, whereas Sj?gren's syndrome can be equally discussed as PBC of the salivary glands. Dissection of the genetic predispositions for both diseases and especially the molecular basis of effector mechanisms, will become critical elements in developing new therapies.     

Immunohistopathology of Sjögren's syndrome

Sj?gren's syndrome (SS) is characterized by keratoconjunctivitis sicca and xerostomia, which occur in an autoimmune lacrimal and salivary gland disease characterized by lymphocyte infiltrates of exocrine glands and/or Sj?gren's syndrome autoantibody production. It has been reported that aquaporin-5 distribution is abnormal in SS, perhaps as a result of paracrine effect of TNF-alpha. Also the neurogenic regulation of the salivary gland is impaired in SS. Apart from functional changes, the syndrome is also characterized by structural abnormalities of the secretory acinar apparatus. The acinar basement membrane is abnormal as it lacks laminin alpha1 chain, which may impair its capability to induce the progenitor cells to differentiate to acinar cells. CRISP-3 and TMPRSS-2 can be used as androgen markers and LIV-1 and Cyr61 as estrogen markers to study the sexual dimorphism of the salivary glands. Patients with SS seem to have low concentrations of dehydroepiandrosterone, which may predispose women and the exocrine glands to this syndrome.     

Immunopathogenesis of Sjögren's syndrome

Sjögren's syndrome (SS) is an autoimmune disease characterized by the sicca symptoms of dry eyes and dry mouth. Glandular dysfunction is thought to arise from destruction associated with lymphocytic infiltration. The degree of glandular destruction, however, does not correlate with the severity of sicca symptoms, suggesting that other mechanisms are involved, including abnormalities in parasympathetic neurotransmission. Autoantibodies against the muscarinic acetylcholine receptor have been implicated in this process, but multiple other autoantibodies have been found. Cytokines elaborated in the inflammatory lesions also appear to be involved and dysregulation of apoptosis are also involved in the pathogenesis of SS. A new two-stage model of SS has been proposed. First, there is a lymphocyte-independent phase during which inappropriate apoptosis results in the generation of apoptotic autoantigens which then attract lymphocytes. Subsequently, in the second lymphocyte-dependent phase, an immune attack causes further cell death and salivary dysfunction. Although the disease generally takes a rather stable and benign course, patients with SS have a significant risk of developing B cell lymphoma.     

Pathogenesis of Sjögren's syndrome

The pathogenesis of Sj?gren's syndrome is poorly understood. Genetic and environmental factors appear to contribute to the development of this syndrome. Viral infection is one of the most likely environmental factors. The primary lesion of Sj?gren's syndrome is in the exocrine glands. A majority of the infiltrating cells in the lesion are CD(4+) CD45RO(+) memory T cells. Although antigen-presentation to T cells seems to occur in the exocrine tissues, these T cells are not fully activated. On the other hand, B cells comprise approximately 20% of the infiltrating cells, and several features of this syndrome are attributed to stimulated B cells. The presence of autoantibodies, such as anti-SS-A/Ro and SS-B/La antibodies, is one of the characteristic features and is associated with severe disorders. Some antibodies appear to play a direct pathogenic role, for example, in cases of congenital heart block and sicca symptoms. Chronic inflammation with possible T cell-dependent antigen stimulation appears to induce neoplastic transformation of lymphocytes.     

Sjögren's syndrome at the crossroad of polyautoimmunity

The coexistence of autoimmune diseases (i.e., polyautoimmunity) in Sj?gren's syndrome (SS) was investigated in a cross-sectional study involving 410 patients. Logistic regression analysis and the Rogers and Tanimoto index were used to evaluate risk factors and clustering, respectively. There were 134 (32.6%) patients with polyautoimmunity. The most frequent and closer coexistent diseases were autoimmune thyroid disease (21.5%), rheumatoid arthritis (8.3%), systemic lupus erythematosus (7.6%), and inflammatory bowel disease (0.7%) which together constituted a cluster group. There were 35 (8.5%) patients with multiple autoimmune syndrome. Besides disease duration, a history of habitual smoking and spontaneous abortion were found to be risk factors for the developing of polyautoimmunity. This study discloses a high prevalence of polyautoimmunity in SS, its associated risk factors and the grouping pattern of such a condition. These results may serve to define plausible approaches to study the common mechanisms of autoimmune diseases.     

Use of muscarinic agonists in the treatment of Sj?gren's syndrome.

Two muscarinic agonists (pilocarpine and cevimeline) have recently been approved for the treatment of symptoms of xerostomia in Sj?gren's syndrome (SS). These agents stimulate the M1 and M3 receptors present on salivary glands, leading to increased secretory function. The use of these agents emphasizes the importance of neuroendocrine mechanisms in SS, which is considered an autoimmune disorder. We review recent studies on the release of cytokines and metalloproteinases in SS-affected glands and their influence on the release of and response to neurotransmitters. Also, we review the structure and function of muscarinic receptors as they may relate to SS and the potential use of novel muscarinic agonists in SS.     

Autoimmune hepatitis in patients with primary Sj?gren's syndrome: a series of two-hundred and two patients

Based on the revised criteria of the American-European Consensus Group, we retrospectively established the diagnosis of primary or secondary Sjögren''s syndrome for 202 patients referred to a Sjögren''s syndrome clinic. Of these, 58 patients and 8 patients fulfilled criteria for primary and secondary Sjögren''s syndrome, respectively. Of the 58 patients with primary Sjögren''s syndrome, one (1.7%) had definite autoimmune hepatitis, as defined by the International Autoimmune Hepatitis Group diagnostic criteria. One additional symptomatic patient who did not fulfill criteria for primary Sjögren''s syndrome had definite autoimmune hepatitis. None of the patients with secondary Sjögren''s syndrome had definite autoimmune hepatitis. Two (1%) of the 194 patients with primary Sjögren''s syndrome or clinical symptoms had primary biliary cirrhosis. These values are lower than those reported by prior studies with smaller patient populations and likely represent a more accurate estimate of the true prevalence of these diseases in patients with primary Sjögren''s syndrome.     

A case of cholestatic autoimmune hepatitis and acute liver failure: an unusual hepatic manifestation of mixed connective tissue disease and Sjögren's syndrome

Although hepatomegaly is reported to occur occasionally in patients with mixed connective tissue disease (MCTD) or Sjögren''s syndrome (SS), autoimmune liver diseases such as primary biliary cirrhosis, sclerosing cholangitis, and autoimmune hepatitis in association with MCTD or SS have rarely been described. We report a case of severe cholestatic autoimmune hepatitis presenting with acute liver failure in a 40-yr-old female patient suffering from MCTD and SS. The diagnosis of MCTD and SS was made at the age of 38. The patient presented severe jaundice and elevation of conjugated bilirubin. The patient denied alcohol and drug use and had no evidence of viral hepatitis. On the 8th day of her hospitalization, the patient developed grade III hepatic encephalopathy. She was diagnosed as autoimmune hepatitis presenting with acute liver failure based on clinical features, positive FANA and anti-smooth muscle antibodies, negative anti-mitochondrial antibodies, high titers of serum globulin, liver biopsy findings, and a good response to corticosteroid therapy, The patient was managed with prednisolone and the clinical symptoms, liver function test results, and liver biopsy findings showed much improvement after steroid therapy.     

Amelioration of lacrimal gland inflammation by oral administration of K-13182 in Sjögren's syndrome model mice

Regulation of the adhesion of mononuclear cells to endothelial cells is considered to be a critical step for the treatment of inflammatory diseases, including autoimmune diseases. K-13182 was identified as a novel inhibitor for these adhesions. K-13182 inhibited the expression of vascular cell adhesion molecule-1 (VCAM-1, CD106) on human umbilical vein endothelial cells (HUVECs) and on mouse vascular endothelial cell line (MAECs) induced by tumour necrosis factor (TNF)-α. K-13182 also inhibited the adhesion of mononuclear cells to these HUVECs and MAECs, indicating that K-13182 suppressed these adhesions mediated by cellular adhesion molecules including VCAM-1. To evaluate the therapeutic effect in autoimmune disease model mice, K-13182 was orally administered to non-obese diabetic (NOD) mice as Sjögren''s syndrome (SS) model mice. Severe destructive inflammatory lesions were observed in the lacrimal glands of vehicle-treated control mice; however, 8-week administration of K-13182 inhibited the mononuclear cell infiltration into the inflammatory lesions of the lacrimal glands. In K-13182-treated mice, the decrease in tear secretion was also prevented compared to the control mice. In addition, the apoptosis and the expression of FasL (CD178), perforin, and granzyme A was suppressed in the lacrimal glands of K-13182-treated mice. Therefore, K-13182 demonstrated the possibility of therapeutic efficacy for the inflammatory region of autoimmune disease model mice. These data reveal that VCAM-1 is a promising target molecule for the treatment of autoimmune diseases as a therapeutic strategy and that K-13182 has the potential as a new anti-inflammatory drug for SS.     

A short review of the pathogenesis of Sjögren's syndrome

Sj?gren's syndrome can present in a heterogeneous manner with symptoms varying from systemic features such as unexplained fever, weight loss and neurological manifestations to the more typical symptoms of dry mucus membranes. There is discussion of the wide differential diagnosis, followed by a brief overview of the diagnosis, extraglandular manifestations and pathogenesis of primary Sj?gren's syndrome.     

Development of autoimmune exocrinopathy resembling Sjögren's syndrome in estrogen-deficient mice of healthy background

Although a number of autoimmune diseases are known to develop in postmenopausal women, the mechanisms by which estrogen deficiency influences autoimmune lesions remain unclear. We speculate that antiestrogenic actions might be a potent factor in the formation of pathogenic autoantigens. Previously, we have identified 120-kd alpha-fodrin as an important autoantigen in Sj?gren's syndrome (SS). When healthy C57BL/6 (B6) mice were treated with an ovariectomy (Ovx), we found a significant increase in TUNEL(+)-apoptotic epithelial cells in the salivary gland cells associated with alpha-fodrin cleavage during 2 and 3 weeks after Ovx. By contrast, no apoptotic cells were found in estrogen receptor-alpha knockout mice. In in vitro studies using primary cultured mouse salivary gland cells and human salivary gland cells, we found a cleavage product of 120-kd alpha-fodrin in cells that had undergone tamoxifen (Tam)-induced apoptosis through caspase activation, especially caspase-1. Adoptive transfer of alpha-fodrin-reactive T cells into Ovx-B6 and -SCID mice resulted in the development of autoimmune exocrinopathy quite similar to SS. These results suggest that estrogen deficiency exerts a crucial influence on autoantigen cleavage, and may cause, in part, autoimmune exocrinopathy in postmenopausal women.     

Classification criteria of Sjögren's syndrome

Sjögren's syndrome (SS) is a chronic, systemic autoimmune disease that affects typically the exocrine glands causing mucosal dryness. Dry eyes and mouth are considered by far the most common and early symptoms of the disease but systemic complications may also occur. In 1993, the preliminary European criteria were proposed and widely accepted, consisting of both subjective and objective criteria. Almost ten years later, these classification criteria were revised by introducing more stringent rules and precise diagnostic procedures leading to the currently used American-European Consensus Group (AECG) criteria. The AECG criteria have been largely employed to conduct epidemiologic and clinical studies of patients with SS and proved to be more specific compared to the preliminary European criteria. The recent American College of Rheumatology/Sjögren's International Collaborative Clinical Alliance (ACR/SICCA) criteria that are based exclusively on objective tests, the stringency of the AECG criteria and the potential therapeutic use of biologic agents in SS clearly set the need for new classification criteria. Whether the new diagnostic approach will further encompass subclinical and early forms of the disease remains to be addressed by the scientific community.