Objective.To address the clinical, serologic, pathologic, and immunogenetic features of sicca syndrome that occurs in systemic lupus erythematosus (SLE), as well as its similarities to, and differences from, sicca syndrome that occurs in primary Sjögren's syndrome (SS).Methods.A cohort of 283 consecutive unselected SLE patients was evaluated for the presence of associated SS using the American–European classification criteria. Clinical and laboratory parameters in SLE patients with SS (SLE–SS) were compared with those in SLE patients without SS (SLE–no SS) and with a group of 86 unselected patients with primary SS.Results.SS was identified in 26 SLE patients (9.2%); the SS preceded the development of lupus in 18 of them (69.2%). Compared with the SLE–no SS group, patients with SLE–SS were significantly older, had a higher frequency of Raynaud's phenomenon, anti‐Ro/SSA, anti‐La/SSB, and rheumatoid factor, but had a significantly lower frequency of renal involvement, lymphadenopathy, and thrombocytopenia. Compared with the primary SS group, SLE–SS patients displayed a clinically similar sicca syndrome, but were significantly younger and had an increased frequency of perivascular infiltrates in the salivary glands associated with anticardiolipin antibodies in the serum. SLE–SS patients had a high frequency of the DRB1*0301 allele. This HLA profile distinguished the SLE–SS group from the SLE–no SS group, who had an increased frequency of DRB1*1501 and DQB1*0602 alleles, but was similar to the HLA profile of the primary SS group, who had an increased frequency of DRB1*0301.Conclusion.SLE–SS appears to constitute a subgroup of patients with distinct clinical, serologic, pathologic, and immunogenetic features, in whom SS is expressed as an overlapping entity and is largely similar to primary SS.

The EULAR Sjögren's syndrome (SS) disease activity index (ESSDAI) is a systemic disease activity index that was designed to measure disease activity in patients with primary SS. With the growing use of the ESSDAI, some domains appear to be more challenging to rate than others. The ESSDAI is now in use as a gold standard to measure disease activity in clinical studies, and as an outcome measure, even a primary outcome measure, in current randomised clinical trials. Therefore, ensuring an accurate and reproducible rating of each domain, by providing a more detailed definition of each domain, has emerged as an urgent need. The purpose of the present article is to provide a user guide for the ESSDAI. This guide provides definitions and precisions on the rating of each domain. It also includes some minor improvement of the score to integrate advance in knowledge of disease manifestations. This user guide may help clinicians to use the ESSDAI, and increase the reliability of rating and consequently of the ability to detect true changes over time. This better appraisal of ESSDAI items, along with the recent definition of disease activity levels and minimal clinically important change, will improve the assessment of patients with primary SS and facilitate the demonstration of effectiveness of treatment for patients with primary SS.

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Objective. Exosomes are membrane vesicles of endosomal origin that are distinct from apoptotic bodies and are thought to represent an acellular mechanism for antigen transfer to classic antigen-presenting cells, as well as for direct antigen presentation with the capacity to induce immune response or tolerance. Nevertheless, it is not known whether exosomes are involved in the induction or regulation of immune responses against intracellular autoantigens that characterize autoimmune diseases. Exosomes have been shown to be secreted by several types of cells, whereas studies of non-neoplastic epithelial cells are lacking. This study was undertaken to investigate the capacity of nonneoplastic salivary gland epithelial cells (SGECs) to release exosomes, and to determine whether epithelial exosomes contain RNPs, which are major autoantigens in systemic rheumatic diseases.Methods. Exosomes were isolated by ultracentrifugation from culture supernatants of 26 non-neoplastic SGEC lines established from patients with various rheumatic disorders. They were analyzed by electron microscopy, immunoblotting, or immunoprecipitation.Results. All SGEC lines were found to release comparable and significant amounts of exosomes. Similar to other cell systems, exosome secretion was constitutive and was unrelated to activation or apoptotic processes. SGEC-derived exosomes were found to contain the autoantigenic Ro/SSA, La/SSB, and Sm RNPs, as well as epithelial-specific cytokeratins.Conclusion. SGECs constitutively secrete exosomes that contain the major autoantigens Ro/SSA, La/SSB, and Sm. This mechanism may represent a pathway whereby intracellular autoantigens are presented to the immune system with an immunogenic or tolerogenic outcome.Autoimmune diseases are characterized by the development of humoral responses against self antigens, most of which are intracellular proteins. Although thought to involve typical antigen-driven responses, the precise mechanism(s) involved in the presentation of such intracellular autoantigens to the immune system is unclear (1). Apoptosis and the resulting release of autoantigen-containing apoptotic vesicles are considered potential pathways for the generation of autoimmune responses (2).During the last decade, a novel cell-free mechanism of antigen presentation has been recognized (3) that involves small (30-100 nm) membrane vesicles, which are termed exosomes and are distinct from apoptotic bodies. These are different from the exosome protein complex, which is implicated in RNA processing and degradation processes. Exosomal vesicles are secreted following the fusion of multivesicular late endosome/lysosomes with the plasma membrane. Exosome production has been observed in a variety of cell types, including reticulocytes, platelets, cytotoxic T lymphocytes and B lymphocytes, dendritic cells, and neoplastic intestinal epithelial cells, whereas studies of non-neoplastic epithelial cells are lacking. Several physiologic roles have been assigned to exosomes, including the expulsion of obsolete membran...

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Objective. To evaluate the expression profile of infiltrating macrophages and dendritic cells (DCs) as well as of interleukin-18 (IL-18) and IL-12 in the minor salivary gland (MSG) lesions of patients with Sjögren's syndrome (SS), and to assess the relationship of these factors with disease parameters.Methods. Macrophages, DCs, T cells, B cells, proIL-18, mature IL-18, and IL-12 were detected by single-and double-labeling immunohistochemistry in MSG specimens from 21 patients with primary SS (13 of 21 tested for IL-12), 7 patients with secondary SS, and 9 disease control patients. Expression profiles were assessed for correlations with various disease parameters, including adverse predictors of lymphoma development.Results. MSGs from patients with SS (but not from disease controls) manifested increased infiltration by macrophages and DCs, strong expression of IL-18 by macrophages (particularly in B cell-rich areas and in germinal center-like structures in primary SS), and expression of IL-12 by mononuclear cell infiltrates. In primary SS, high infiltration by macrophages correlated with SG enlargement (P ‫؍‬ 0.01). The DC infiltration rate correlated positively with the macrophage infiltration rate (P ‫؍‬ 0.04), occurrence of SG enlargement (P ‫؍‬ 0.03), and presence of C4 hypocomplementemia (P ‫؍‬ 0.05), and inversely with serum C4 complement levels (P ‫؍‬ 0.001). The rate of infiltration by IL-18-expressing cells correlated positively with biopsy focus scores (P < 0.001), larger infiltrates of macrophages (P ‫؍‬ 0.01), DCs (P ‫؍‬ 0.01), and B cells (P ‫؍‬ 0.02), and SG enlargement (P ‫؍‬ 0.02), and negatively with serum C4 complement levels (P ‫؍‬ 0.02). The rate of infiltration by IL-12-expressing cells correlated inversely with that by IL-18-expressing cells (P ‫؍‬ 0.001), biopsy focus scores (P ‫؍‬ 0.003), and SG enlargement (P ‫؍‬ 0.01), and positively with serum C4 complement levels (P ‫؍‬ 0.05).Conclusion. In patients with primary SS, infiltration of the SG by macrophages and DCs and expression of IL-18 and IL-12 appear to play active roles in the expansion and organization of infiltrative injuries and have a correlation with certain predictors of lymphoma development.

Objective. To investigate the expression of B7 costimulatory molecules in the lymphoepithelial lesions of salivary gland (SG) biopsy tissues and in SG epithe-lial cell lines derived from patients with Sjögren's syndrome (SS). Methods. B7.1 and B7.2 protein expression was studied by immunohistochemistry in minor SGs obtained from 11 patients with SS and 10 disease control patients with nonspecific sialadenitis and in cultured SG epithelial cell lines obtained from minor SGs from 15 SS patients and 15 control patients. B7.1 and B7.2 messenger RNA (mRNA) expression by SG epithelial cell lines was examined by reverse transcription-polymerase chain reaction (RT-PCR). Results. In biopsy tissues from SS patients, but not control patients, ductal and acinar epithelial cells showed increased expression of both B7.1 and B7.2. Intense spontaneous B7.1 protein expression (as well as HLA-ABC, but not B7.2 or HLA-DR) was also found in 73% of SG epithelial cell lines from SS patients versus 13% of those from control patients (P < 0.01). Interferon-treatment induced, or up-regulated, B7.1, B7.2, and HLA-DR expression in all SG epithelial cell lines tested. B7.1 and B7.2 expression by SG epithelial cell lines was also verified at the mRNA level by RT-PCR. Conclusion. Human SG epithelia are intrinsically capable of expressing B7 proteins upon activation. In SS patients, the expression of B7 molecules by SG epithe-lial tissues and by SG epithelial cell lines indicates the activated status of SG epithelial cells in this disorder and, possibly, their capacity for presenting antigens to T cells.

SUMMARYCD40 has been identified in an expanding list of haematopoietic and non-haematopoietic cells and has received an increased interest based on its role in a variety of cell-mediated responses and its potential to participate in the pathogenesis of chronic inflammatory disorders. Sjögren's syndrome (SS) is an autoimmune exocrinopathy, which is characterized by chronic lymphocytic infiltration of exocrine glands and aberrant activation of epithelial tissues. We studied the expression of CD40 protein in cultured non-neoplastic salivary gland epithelial cell (SGEC) lines as well as in minor SG biopsies obtained from 17 SS patients and 12 controls. Immunocytochemical and flow cytometric analyses had revealed the occurrence of constitutively expressed CD40 molecules on the surface of long-term cultured SGEC lines, which could be further induced by interferon-gamma (IFN-g) and IL-1b cytokines, but not tumour necrosis factor-alpha (TNF-a), IL-4, IL-6, granulocyte-macrophage colony-stimulating factor (GM-CSF) or IFN-a. Triggering of SGEC through CD40 enhanced the surface expression of the adhesion molecule intercellular adhesion molecule-1 (ICAM-1)/CD54, but not MHC class I and class II (HLA-DR) molecules. Spontaneous CD40 expression was significantly higher in SGEC lines derived from SS patients, compared with controls (P < 0·001), which is suggestive of their intrinsically activated status. In SG biopsies, CD40 was constitutively expressed by lymphocytes, ductal epithelial cells and endothelial cells but not by other glandular cell types, such as acinar cells, myoepithelial cells and fibroblasts. In addition, CD40L staining was also detected in 30-50% of the infiltrating lymphocytes in the biopsies of SS patients. Our findings indicate the immunoregulatory potential of SGEC and lend further support to a model of intrinsic activation in salivary epithelia in SS, whereby these cells actively participate in the induction and maintenance of lymphocytic infiltrates of patients.