AB0136 Induction of reg ia, a new auto-antigen in sjögren’s syndrome patients, in salivary duct epithelial cells by interleukin-6 and -11

AB0189 Interleukin-6/Stat Pathway is Responsible for the Induction of REG Iα, A New Auto-Antigen in SjÖGren's Syndrome Patients, in Salivary Duct Epithelial Cells

The regenerating gene, Reg, was originally isolated from a rat regenerating islet complementary DNA (cDNA) library, and its human homologue was named REG Iα. Recently, we reported that REG Iα messenger RNA (mRNA), as well as its product, was overexpressed in ductal epithelial cells in the salivary glands of Sjögren's syndrome patients. Furthermore, autoantibodies against REG Iα were found in the sera of Sjögren's syndrome patients, and the patients who were positive for the anti-REG Iα antibody showed significantly lower saliva secretion than antibody-negative patients. We found the mechanism of REG Iα induction in salivary ductal epithelial cells. Reporter plasmid containing REG Iα promoter (-1190/+26) upstream of a luciferase gene was introduced into human NS-SV-DC and rat A5 salivary ductal cells. The cells were treated with several cytokines (interleukin (IL)-6, IL-8, etc.), upregulated in Sjögren's syndrome salivary ducts, and the transcriptional activity was measured. IL-6 stimulation significantly enhanced the REG Iα promoter activity in both cells. Deletion analysis revealed that the -141∼-117 region of the REG Iα gene was responsible for the promoter activation by IL-6, which contains a consensus sequence for signal transducer and activator of transcription (STAT) binding. The introduction of small interfering RNA for human STAT3 abolished IL-6-induced REG Iα transcription. These results indicated that IL-6 stimulation induced REG Iα transcription through STAT3 activation and binding to the REG Iα promoter in salivary ductal cells. This dependence of REG Iα induction upon IL-6/STAT in salivary duct epithelial cells may play an important role in the pathogenesis/progression of Sjögren's syndrome.

Interleukin-6/STAT pathway is responsible for the induction of gene expression of REG Iα, a new auto-antigen in Sjögren׳s syndrome patients, in salivary duct epithelial cells

The regenerating gene (Reg) was isolated originally as a gene specifically over-expressed in regenerating pancreatic islets and constitute a growth factor family. Reg gene product (Reg) is important in the pathophysiology of various human inflammatory diseases. Recently, the possible involvement of human REG in the regeneration of salivary ductal epithelial cells of patients with primary Sjögren's syndrome (SS) was reported. However, the expression of the REG family genes in minor salivary glands (MSG) and the occurrence of anti-REG Iα autoantibodies in SS patients were obscured. In this study, we examined the expression of REG family genes in the MSG of SS and screened anti-REG Iα autoantibodies in SS. The mRNA levels of REG family genes in MSG were quantified using real-time reverse transcription-polymerase chain reaction (RT-PCR) and REG Iα expression in the MSG was analysed by immunohistochemistry. The mRNA level of REG Iα in the MSG of SS patients was significantly higher than that of control. REG Iα protein was expressed highly in SS ductal epithelial cells. Anti-REG Iα autoantibodies in the sera were found in 11% of SS. All the MSG in the anti-REG Iα autoantibody-positive group showed REG Iα expression, whereas only 40% showed REG Iα expression in the anti-REG Iα autoantibody-negative group. The anti-REG Iα autoantibody-positive group showed significantly lower saliva secretion and a higher ratio of grade 4 (by Rubin-Holt) in sialography. These data suggest strongly that autoimmunity to REG Iα might play a role in the degeneration of MSG ductal epithelial cells in primary SS.

Sjögren syndrome (SS) is an autoimmune disease characterized by diffuse lymphoid cell infiltrates in the salivary and lacrimal glands, resulting in symptoms of dry mouth and eyes due to insufficient secretion. Although it has been assumed that a combination of immunologic, genetic and environmental factors may play a key role in the development of autoimmune lesions in the salivary and lacrimal glands, little is known about the disease pathogenesis of SS in humans. We have identified the 120 kDa alpha-fodrin as an important autoantigen in the development of SS in both an animal model and SS patients, but the mechanism of alpha-fodrin cleavage leading to tissue destruction in SS remains unclear. Tissue-infiltrating CD4+ T cells purified from the salivary glands of a mouse model for SS bear a large proportion of Fas ligand and the salivary gland duct cells possess apoptotic receptor Fas. Anti-Fas antibody-induced apoptotic salivary gland cells result in specific alpha-fodrin cleavage to the 120 kDa fragment in vitro. Preincubation with a combination of calpain and caspase inhibitor peptides could be responsible for inhibition of the 120 kDa alpha-fodrin cleavage. Thus, an increase in apoptotic protease activities including calpain and caspases may be involved in the progression of alpha-fodrin proteolysis and tissue destruction in the development of SS.

Systemic and Local Interleukin-17 and Linked Cytokines Associated with Sjögren’s Syndrome Immunopathogenesis

AB0222 Monocyte-derived IL-32 expression correlates with the level of inflammation in salivary glands of sjÖgren’s syndrome

Salivary function provides host protection, assists in the initiation of food and fluid intake, and enables communication through speech. Without adequate salivary output, oral and pharyngeal health declines along with a person’s quality of life. The complaint of a dry mouth (xerostomia) and the objective finding of salivary dysfunction are common occurrences in older individuals, producing transient and permanent oral and systemic problems. Salivary dysfunction, however, is not a normal consequence of growing older, and is due to systemic diseases, medications, and head and neck radiotherapy. Diagnosis of salivary disorders begins with a careful medical history, head, and neck examination. While complaints of xerostomia may be indicative of a salivary gland disorder, salivary diseases can present without symptoms. Therefore, routine examination of salivary function must be part of any head, neck, and oral examination. Therapies are designed to prevent the development of oral and pharyngeal sequelae of salivary hypofunction. Current xerostomia-based treatments include replacement therapies and gustatory, masticatory, and pharmacological stimulants. Healthcare professionals can play a vital role in identifying patients at risk for developing salivary dysfunction, and should provide appropriate preventative and interventive techniques that will help preserve a person’s health, function, and quality of life.

New T-cell epitope of Ro/SS-A 52 kDa protein in labial salivary glands from patients with Sjögren's syndrome

Lacrimal Gland in Sjögren's Syndrome

Analysis of Lymphocyte Monoclonality in Patients with Sjögren's Syndrome Associated with Lymphoproliferative Disorder or Lymphoma.

Primary Sjogren's syndrome is an autoimmune disorder characterized by lymphocytic infiltration of the salivary and lacrimal glands, producing associated dry eyes (keratoconjunctivitis sicca), dry mouth, and intermittently swollen salivary glands. A high proportion of the infiltrating B lymphocytes express surface and cytoplasmic Ig bearing a kappa-L chain-associated CRI defined by reactivity with the murine mAb, 17.109. To determine the structural basis for CRI expression in this disease, we generated CRI+ lymphoblastoid cell lines and a cDNA library from lymphocytes extracted from Sjogren's syndrome patients' salivary gland biopsy specimens. Nucleic acid sequence analyses of the mRNA of one such 17.109-CRI+ lymphoblastoid cell line (NOV) reveals the expressed kappa light chain variable region gene (V kappa gene) to be homologous to Humkv325, a conserved V kappa gene used at relatively high frequency in certain B cell malignancies. In addition, synthetic oligonucleotides, corresponding to the first and third frameworks and the second complementarity determining region of the Humkv325 gene, were used to identify and isolate clones from a cDNA library generated from SS salivary gland lymphocytes. Clones annealing specifically with one or more of these oligonucleotide probes contained kappa light chain cDNA. The sequences corresponding to the variable region of two clones (Taykv320 and Taykv306) were homologous to Humkv325. The V kappa genes of four other cDNA clones (Taykv322, Taykv310, Taykv308, and Taykv312) most likely were generated somatically from the rearranged Humkv325 gene through a limited number of nucleic acid base substitutions. Our results suggest that the high frequency of 17.109-CRI expression in Sjogren's syndrome patients results from a multiclonal expansion of B cells using Humkv325, and that the expressed Humkv325 may undergo somatic diversification in an apparent Ag-driven response.

We attempted to determine whether cell adhesion molecules, including vascular cell adhesion molecule-1 (VCAM-1), intercellular adhesion molecule-1 (ICAM-1), and E-selectin (endothelial-leukocyte adhesion molecule-1; ELAM-1), are involved in the lymphoid cell infiltration of the salivary and lacrimal glands in Sjogren's syndrome (SS) patients. Both immunohistochemical analysis and the reverse-transcripts polymerase chain reaction (RT-PCR) were used to analyze the expression of VCAM-1, ICAM-1, ELAM-1, very late antigen 4 (VLA-4 [alpha 4,beta 1]), lymphocyte function-associated antigen-1 (LFA-1), interferon-gamma (IFN-gamma), tumor necrosis factor (TNF), and interleukin-1 beta (IL-1 beta). Immunohistochemical analysis of salivary gland biopsies from SS patients showed a marked expression of VCAM-1 and ICAM-1 in the venules surrounded by infiltrated CD4+ CD45RO+ T cells. E-selectin was expressed on vascular endothelium with weak intensity. Increased levels of VCAM-1, ICAM-1, IFN-gamma, and IL-1 beta mRNA were demonstrated by RT-PCR, whereas E-selectin mRNA were weakly expressed in SS lacrimal and salivary gland tissues. This is in contrast with strong expression of ELAM-1 in IL-1 beta-stimulated human umbilical vascular endothelial cells (HUVEC) in vitro. Cytokine-mediated up-regulation of VCAM-1 and ICAM-1 that facilitates the recruitment of VLA-4 and LFA-1 expressing T cells might contribute to lymphoid cell infiltration in the salivary and lacrimal glands in SS.

Background A third of Sjögren’s syndrome (SS) patients develop ectopic lymphoid structures (ELS) in their salivary glands (SG). ELS play an active role in autoimmunity and contribute to the development of MALT lymphoma. Interleukin 27 (IL-27) exerts key immunomodulatory actions on numerous immune cells but its role in the formation and regulation of ELS in the SG of SS is unknown. Here we used a murine model of SG ELS to elucidate the role of IL-27 and its interaction with IL-17 in the development, regulation and function of ELS. We extended our observations on a cohort of SS patients to identify IL-27 cellular source, target cells and functional properties in modulating CD4 T cells function. Methods A single dose of reporter-encoding adenovirus was delivered directly to the SG of wild-type (WT) and IL-27RA-deficient (KO) mice to trigger ELS formation. For IL-17 blockade, anti-mouse IL-17A antibody was used. ELS development and peripheral immune responses were tracked by immuno-histopathology, FACS, and qPCR. Minor SG biopsies were collected from SS and non-specific sialadenitis (sicca) patients. Peripheral blood mononuclear cells (PBMC) isolated from SS and rheumatoid arthritis (RA) patients and age/sex-matched healthy donors (HD). For in vitro experiments PBMCs were incubated with IL-27 and analysed by FACS and cytokines levels were measured in culture supernatants. Tissue IL-27 was assessed by multicolour immunofluorescence. Results In WT mice, SG ELS formation was preceded by upregulation of IL-27p28 and infiltration of IL-27 producing cells. KO mice displayed larger, more abundant ELS in the SG. Higher expression levels of ELS-related genes (Cxcl13, Ccl19, Ltb, Aid) compared to WT mice were measured. KO mice showed an uncontrolled SG Th17 response and systemic IL-17A blockade caused a reduction in ELS size and in the expression of ELS-related genes. In SS patients SG and serum, we observed higher expression levels of IL-27 transcripts and protein, compared to sicca. SG IL-27 was selectively increased in ELS+ patients. IL-27 staining was detected in the T cell-rich areas of SG ELS often co-localizing with DC-LAMP+ dendritic cells. While IL-27 was able to significantly downregulate IL-17 production in HD and RA, CD4 T cells from patients with SS failed to downregulate IL-17 but showed an aberrant IFNγ release upon IL-27 incubation. Conclusion The IL-27-mediated restriction of Th17 expansion plays a critical role in the regulation of germinal centre response. Both in murine inducible ELS and in patients with SS, dendritic cells appear as the main cellular source of IL-27. IL-27 consistently failed to downregulate IL-17 release in CD4 T cells from SS patients, albeit its expression was increased in the ELS+ subset of SS, suggesting that a profound dysregulation of the IL-27/IL-17 axis play an important role in ELS formation in this condition. Disclosures D. Lucchesi None. R. Coleby None. E. Pontarini None. E. Prediletto None. F. Rivellese None. D. Hill None. A. Derrac Soria None. S. Jones None. I. Humphreys None. N. Sutcliffe None. A. Tappuni None. C. Pitzalis None. G. Jones None. M. Bombardieri None.

SS represents a chronic autoimmune disease of salivary and lacrimal glands that may be accompanied by multi-organ systemic manifestations. Among the locally involved innate immune defense populations are macrophages, which have been linked to IL-12 and IL-23 that moderate T lymphocyte lineage commitment. To further an understanding of the immunopathologic sequelae associated with SS and to define therapeutic targets, we performed microarray analysis of target tissues from SS patients with severe histopathologic lesions compared to those with sicca symptomatology but negative minor salivary gland biopsy. We identified the expression of multiple genes, including members of the mammalian chitinase family, not previously associated with exocrinopathies, among the most highly expressed SS genes as compared to diseased, but non-SS tissues. Both chitinase-3-like-1 (CHI3L1/YKL-40) and chitinase 1 (CHIT1), highly conserved members of the mammalian chitinase-like glycoprotein family, one with and one lacking enzymatic activity, were evident at the transcriptome levels, as well as detected as glycoproteins within inflamed salivary glands. Monocyte to macrophage differentiation is accompanied by an increase in chitinase expression, which can be augmented by cytokine exposure. Since the elevated expression of these molecules corresponded with more advanced disease in SS patients, these observations suggested a potential immunopathologic involvement.