X chromosome dose and sex bias in autoimmune diseases: increased 47,XXX in systemic lupus erythematosus and Sjögren’s syndrome (BA4P.211)

Mechanism for female predominance in autoimmunity is unknown. We suspected an X chromosome dose effect and predicted if so, triple X (47,XXX, 1 in ~1,000 live female births) would be increased in female predominant diseases (systemic lupus erythematosus [SLE], primary Sjögren’s syndrome [SS], primary biliary cirrhosis [PBC] and rheumatoid arthritis [RA])compared to diseases without female predominance (sarcoidosis, granulomatosis with polyangiitis [GPA]) and healthy controls. We used single nucleotide polymorphism (SNP) arrays to identify 47,XXX and fluorescent in situ hybridization, or q-PCR to confirm when possible. 47,XXX was found in 7 of 2,948 SLE and 3 of 1,053 SS female patients, but in none of the 4,822 female controls (OR≥21.31, 95% CI: 2.36-∞, p=0.001 and OR≥22.95, 95% CI: 1.89-∞, p=0.006, respectively). One 47,XXX was present for every ~421 SLE women and ~351 SS women. In addition, we identified one 47,XXX from each of 1,159 women with PBC and 943 with sarcoidosis. No 47,XXX was identified among 453 women with RA or 247 with GPA. In conclusion, 47,XXX was present in excess among SLE and SS subjects as predicted by X chromosome dose effect. These estimated prevalence of SLE and SS with 47,XXX being respectively ~2.4 and ~2.8 times higher than in women with 46,XX and ~24 and ~39 times higher than in men with 46,XY. There was no increase of 47,XXX is other female-biased diseases, suggesting multiple pathways to such a bias in autoimmunity.

CD11c(+) dendritic cells rather than Langerhans cells are reduced in normal skin of immunosuppressed renal transplant recipients

The increased risk of squamous cell carcinomas (SCC) in renal transplant recipients (RTR) is related to impaired immunosurveillance as a consequence of immunosuppressive therapy. Since dendritic cells (DC) play an important role in immunosurveillance, we investigated the quantity of DC subsets and macrophages in normal skin of RTR and immunocompetent controls by immunohistochemistry. In this comparative study Langerhans' cells (LC) were present in similar numbers in RTR and controls. The number of CD11c+ DC was significantly reduced in RTR, particularly in patients on triple treatment therapy, compared with controls. Macrophages were significantly increased. Plasmacytoid DC were not detected in normal skin. The reduced quantity of CD11c+ DC and increased number of macrophages in normal skin of immunosuppressed RTR may contribute to the increased incidence of SCC in RTR. This finding underlines the role of DC subsets in immunosurveillance, and may have implications for our understanding of the effect of immunosuppression on DC subsets.

NCR3/NKp30 contributes to pathogenesis in primary Sjogren's syndrome

Primary Sjögren's syndrome (pSS) is a chronic autoimmune disease characterized by a lymphocytic exocrinopathy. However, patients often have evidence of systemic autoimmunity, and they are at markedly increased risk for the development of non- Hodgkin's lymphoma. Similar to other autoimmune disorders, a strong interferon (IFN) signature is present among subsets of pSS patients, although the precise etiology remains uncertain. NCR3/NKp30 is a natural killer (NK)-specific activating receptor regulating the cross talk between NK and dendritic cells and type II IFN secretion. We performed a case-control study of genetic polymorphisms of the NCR3/NKp30 gene and found that rs11575837 (G>A) residing in the promoter was associated with reduced gene transcription and function as well as protection to pSS. We also demonstrated that circulating levels of NCR3/NKp30 were significantly increased among pSS patients compared with controls and correlated with higher NCR3/NKp30 but not CD16-dependent IFN-γ secretion by NK cells. Excess accumulation of NK cells in minor salivary glands correlated with the severity of the exocrinopathy. B7H6, the ligand of NKp30, was expressed by salivary epithelial cells. These findings suggest that NK cells may promote an NKp30-dependent inflammatory state in salivary glands and that blockade of the B7H6/NKp30 axis could be clinically relevant in pSS.

Comparison of the American-European Consensus Group Sjogren's syndrome classification criteria to newly proposed American College of Rheumatology criteria in a large, carefully characterised sicca cohort

OBJECTIVE

To compare the performance of the American-European Consensus Group (AECG) and the newly proposed American College of Rheumatology (ACR) classification criteria for Sjögren's Syndrome (SS) in a well-characterised sicca cohort, given ongoing efforts to resolve discrepancies and weaknesses in the systems.

METHODS

In a multidisciplinary clinic for the evaluation of sicca, we assessed features of salivary and lacrimal gland dysfunction and autoimmunity as defined by tests of both AECG and ACR criteria in 646 participants. Global gene expression profiles were compared in a subset of 180 participants.

RESULTS

Application of the AECG and ACR criteria resulted in classification of 279 and 268 participants with SS, respectively. Both criteria were met by 244 participants (81%). In 26 of the 35 AECG+/ACR participants, the minor salivary gland biopsy focal score was ≥1 (74%), while nine had positive anti-Ro/La (26%). There were 24 AECG-/ACR+ who met ACR criteria mainly due to differences in the scoring of corneal staining. All patients with SS, regardless of classification, had similar gene expression profiles, which were distinct from the healthy controls.

CONCLUSIONS

The two sets of classification criteria yield concordant results in the majority of cases and gene expression profiling suggests that patients meeting either set of criteria are more similar to other SS participants than to healthy controls. Thus, there is no clear evidence for increased value of the new ACR criteria over the old AECG criteria from the clinical or biological perspective. It is our contention, supported by this report, that improvements in diagnostic acumen will require a more fundamental understanding of the pathogenic mechanisms than is at present available.

Association of genes in the NF-κB pathway with antibody-positive primary Sjögren's syndrome

Primary Sjögren's syndrome (SS) is a systemic autoimmune inflammatory disease characterized by focal lymphocytic infiltrates in the lachrymal and salivary glands and autoantibodies against the SSA/Ro and SSB/La antigens. Experimental studies have shown an activation of NF-κB in primary SS. NF-κB activation results in inflammation and autoimmunity and is regulated by inhibitory and activating proteins. Genetic studies have shown an association between multiple autoimmune diseases and TNFAIP3 (A20) and TNIP1 (ABIN1), both repressors of NF-κB and of IKBKE (IKKε), which is an NF-κB activator. The aim of this study was to analyse single nucleotide polymorphisms (SNPs) in the IKBKE, NFKB1, TNIP1 and TNFAIP3 genes for association with primary SS. A total of 12 SNPs were genotyped in 1105 patients from Scandinavia (Sweden and Norway, n = 684) and the UK (n = 421) and 4460 controls (Scandinavia, n = 1662, UK, n = 2798). When patients were stratified for the presence of anti-SSA and/or anti-SSB antibodies (n = 868), case-control meta-analysis found an association between antibody-positive primary SS and two SNPs in TNIP1 (P = 3.4 × 10(-5) , OR = 1.33, 95%CI: 1.16-1.52 for rs3792783 and P = 1.3 × 10(-3) , OR = 1.21, 95%CI: 1.08-1.36 for rs7708392). A TNIP1 risk haplotype was associated with antibody-positive primary SS (P = 5.7 × 10(-3) , OR = 1.47, 95%CI: 1.12-1.92). There were no significant associations with IKBKE, NFKB1 or TNFAIP3 in the meta-analysis of the Scandinavian and UK cohorts. We conclude that polymorphisms in TNIP1 are associated with antibody-positive primary SS.

Transcriptional landscapes of emerging autoimmunity: transient aberrations in the targeted tissue's extracellular milieu precede immune responses in Sjögren's syndrome

Introduction

Our understanding of autoimmunity is skewed considerably towards the late stages of overt disease and chronic inflammation. Defining the targeted organ’s role during emergence of autoimmune diseases is, however, critical in order to define their etiology, early and covert disease phases and delineate their molecular basis.

Methods

Using Sjögren’s syndrome (SS) as an exemplary rheumatic autoimmune disease and temporal global gene-expression profiling, we systematically mapped the transcriptional landscapes and chronological interrelationships between biological themes involving the salivary glands’ extracellular milieu. The time period studied spans from pre- to subclinical and ultimately to onset of overt disease in a well-defined model of spontaneous SS, the C57BL/6.NOD-Aec1Aec2 strain. In order to answer this aim of great generality, we developed a novel bioinformatics-based approach, which integrates comprehensive data analysis and visualization within interactive networks. The latter are computed by projecting the datasets as a whole on a priori-defined consensus-based knowledge.

Results

Applying these methodologies revealed extensive susceptibility loci-dependent aberrations in salivary gland homeostasis and integrity preceding onset of overt disease by a considerable amount of time. These alterations coincided with innate immune responses depending predominantly on genes located outside of the SS-predisposing loci Aec1 and Aec2. Following a period of transcriptional stability, networks mapping the onset of overt SS displayed, in addition to natural killer, T- and B-cell-specific gene patterns, significant reversals of focal adhesion, cell-cell junctions and neurotransmitter receptor-associated alterations that had prior characterized progression from pre- to subclinical disease.

Conclusions

This data-driven methodology advances unbiased assessment of global datasets an allowed comprehensive interpretation of complex alterations in biological states. Its application delineated a major involvement of the targeted organ during the emergence of experimental SS.

Variants at multiple loci implicated in both innate and adaptive immune responses are associated with Sjögren's syndrome

Sjögren’s syndrome is a common autoimmune disease (~0.7% of European Americans) typically presenting as keratoconjunctivitis sicca and xerostomia. In addition to strong association within the HLA region at 6p21 (P_meta=7.65×10⁻¹¹⁴), we establish associations with IRF5-TNPO3 (P_meta=2.73×10⁻¹⁹), STAT4 (P_meta=6.80×10⁻¹⁵), IL12A (P_meta =1.17×10⁻¹⁰), FAM167A-BLK (P_meta=4.97×10⁻¹⁰), DDX6-CXCR5 (P_meta=1.10×10⁻⁸), and TNIP1 (P_meta=3.30×10⁻⁸). Suggestive associations with P_meta<5×10⁻⁵ were observed with 29 regions including TNFAIP3, PTTG1, PRDM1, DGKQ, FCGR2A, IRAK1BP1, ITSN2, and PHIP amongst others. These results highlight the importance of genes involved in both innate and adaptive immunity in Sjögren’s syndrome.

Porphyromonas gingivalis facilitates the development and progression of destructive arthritis through its unique bacterial peptidylarginine deiminase (PAD)

Rheumatoid arthritis and periodontitis are two prevalent chronic inflammatory diseases in humans and are associated with each other both clinically and epidemiologically. Recent findings suggest a causative link between periodontal infection and rheumatoid arthritis via bacteria-dependent induction of a pathogenic autoimmune response to citrullinated epitopes. Here we showed that infection with viable periodontal pathogen Porphyromonas gingivalis strain W83 exacerbated collagen-induced arthritis (CIA) in a mouse model, as manifested by earlier onset, accelerated progression and enhanced severity of the disease, including significantly increased bone and cartilage destruction. The ability of P. gingivalis to augment CIA was dependent on the expression of a unique P. gingivalis peptidylarginine deiminase (PPAD), which converts arginine residues in proteins to citrulline. Infection with wild type P. gingivalis was responsible for significantly increased levels of autoantibodies to collagen type II and citrullinated epitopes as a PPAD-null mutant did not elicit similar host response. High level of citrullinated proteins was also detected at the site of infection with wild-type P. gingivalis. Together, these results suggest bacterial PAD as the mechanistic link between P. gingivalis periodontal infection and rheumatoid arthritis.

Clinical and epidemiological data indicates that chronic periodontal disease (PD), one of the most prevalent infectious inflammatory disease of mankind, is linked to systemic inflammatory diseases such as cardiovascular diseases (CVD), rheumatoid arthritis (RA) and chronic obstructive pulmonary disease (COPD). Nevertheless, the causative mechanisms of association between PD and chronic inflammatory diseases are very poorly understood. Recent findings suggest a causative link between periodontal infection and rheumatoid arthritis via bacteria-dependent induction of a pathogenic response to citrullinated epitopes. In present study we show that infection with viable periodontal pathogen Porphyromonas gingivalis but not another oral bacterium (Prevotella intermedia), exacerbated CIA, as manifested by earlier onset, accelerated progression and enhanced severity of the disease, including significantly increased bone and cartilage destruction. The ability of P. gingivalis to augment CIA was dependent on the expression of a unique enzyme peptidylarginine deiminase, which converts arginine residues in proteins to citrulline. This knowledge may create new perspectives in the treatment and prevention of RA in susceptible individuals.

A possible genetic association with chronic fatigue in primary Sjögren's syndrome: a candidate gene study

Fatigue is prevalent and disabling in primary Sjögren's syndrome (pSS). Results from studies in chronic fatigue syndrome (CFS) indicate that genetic variation may influence fatigue. The aim of this study was to investigate single nucleotide polymorphism (SNP) variations in pSS patients with high and low fatigue. A panel of 85 SNPs in 12 genes was selected based on previous studies in CFS. A total of 207 pSS patients and 376 healthy controls were genotyped. One-hundred and ninety-three patients and 70 SNPs in 11 genes were available for analysis after quality control. Patients were dichotomized based on fatigue visual analogue scale (VAS) scores, with VAS <50 denominated "low fatigue" (n = 53) and VAS ≥50 denominated "high fatigue" (n = 140). We detected signals of association with pSS for one SNP in SLC25A40 (unadjusted p = 0.007) and two SNPs in PKN1 (both p = 0.03) in our pSS case versus control analysis. The association with SLC25A40 was stronger when only pSS high fatigue patients were analysed versus controls (p = 0.002). One SNP in PKN1 displayed an association in the case-only analysis of pSS high fatigue versus pSS low fatigue (p = 0.005). This candidate gene study in pSS did reveal a trend for associations between genetic variation in candidate genes and fatigue. The results will need to be replicated. More research on genetic associations with fatigue is warranted, and future trials should include larger cohorts and multicentre collaborations with sharing of genetic material to increase the statistical power.

Characterization of monocyte-derived dendritic cells from immunosuppressed renal transplant recipients with and without squamous cell carcinomas

Renal transplant recipients (RTR) have a high risk of tumour development, especially cutaneous squamous cell carcinomas (SCC), due to long-term immunosuppressive therapy. RTR may develop multiple lesions over short time periods, and these are often more aggressive with a higher risk of local recurrence and metastasis resulting in increased morbidity and mortality in these patients. Therefore, we took the first step towards evaluating the possibility of generating a therapeutic vaccine based on monocyte-derived dendritic cells (moDC) for these patients. We analysed the phenotype and cytokine/chemokine profile of moDC from long-term immunosuppressed RTR with and without previous SCC. The number of peripheral blood mononuclear cells (PBMC) isolated per ml blood as well as the efficiency of generating moDC from peripheral blood mononuclear cells (PBMC) was similar in patients and immunocompetent controls. Phenotype and cytokine/chemokine profile of the moDC from immunosuppressed patients were similar to those from immunocompetent controls, making moDC-based immunotherapy a potential future treatment option for RTR with multiple SCC.

Type 1 regulatory T cells and regulatory B cells induced by tolerogenic dendritic cells

Dendritic cells (DC) are professional antigen-presenting cells that are capable of both activating immune responses and inducing tolerance. Several studies have revealed efficiency of therapeutic vaccination with tolerogenic DC (tolDC) in inhibition of experimental autoimmunity. The purpose of this study was to compare four different protocols for generation of tolDC - the antidiabetic drug troglitazone (TGZ DC), NF-κB inhibitor BAY 11-7082 (BAY DC), prostaglandin D2 metabolite 15d-PGJ2 (PGJ DC) and a combination of dexamethasone and 1α,25-dihydroxyvitamin D3 (DexVD3 DC) regarding phenotype, cytokine production and T cell stimulatory capacity. TGZ DC and BAY DC had a phenotype comparable to immature DC, while DexVD3 DC were more macrophage like. Analysis of cytokine production using cell culture supernatants from all DC populations revealed that DexVD3 DC were efficient producers of IL-10 and produced less pro-inflammatory cytokines. T cells primed with DexVD3 DC showed reduced proliferation, and further analyses of these T cells revealed that functionally effective type 1 regulatory T cells (Tr1) but not FoxP3(+) Treg were induced. Furthermore, DexVD3 DC promoted the induction of regulatory B cells (Breg). Together, these results indicate that DexVD3 DC have the best potential to be used in a tolerogenic antigen-presenting cell-based immunotherapy setting.

In vitro suppression of immune responses using monocyte-derived tolerogenic dendritic cells from patients with primary Sjögren's syndrome

INTRODUCTION

Therapeutic vaccination with antigen-specific tolerogenic dendritic cells (tolDC) might become a future option of individualized therapy for patients with autoimmune diseases. In this study, we tested the possibility of generating monocyte-derived tolDC from patients with primary Sjögren's syndrome (pSS). We analyzed phenotype, cytokine production and ability to suppress Ro/La-specific immune responses.

METHODS

Monocyte-derived tolDC from patients with pSS were generated in the presence of dexamethasone, vitamin D3 and lipopolysaccharide (DexVD3 DC). The phenotype was analyzed by flow cytometry and the cytokine profile was investigated using a 25-plex Luminex assay and ELISA. The capacity to both stimulate Ro/La-specific T cells and suppress this response was evaluated by autologous mixed lymphocyte reaction (MLR).

RESULTS

DC generated from patients with pSS had a similar phenotype and cytokine profile to those from healthy controls. DexVD3 DC from pSS patients induced little antigen-specific T cell proliferation, but DexVD3 DC-primed lymphocytes successfully suppressed Ro/La-specific T cell responses.

CONCLUSIONS

DexVD3 DC presenting Ro/La antigens might be a promising new therapeutic option for patients with pSS.

Glutaminyl cyclases as novel targets for the treatment of septic arthritis

BACKGROUND

Septic arthritis is a severe and rapidly debilitating disease mainly caused by Staphylococcus aureus. Here, we assess the antiarthritic efficiency of glutaminyl cyclase (QC) inhibitors.

METHODS

Mice were inoculated with an arthritogenic amount of S. aureus intravenously or by local administration into the knee joint. Animals were treated with QC inhibitors (PBD155 and PQ529) via chow during the experiment. QC and isoQC knockout mice were also analyzed for arthritis symptoms after local administration of bacteria.

RESULTS

Both QC inhibitors significantly delayed the onset of clinical signs of arthritis, and inhibitors significantly decreased weight loss in treated animals. Following intraarticular injection of S. aureus, PBD155-treated mice had lower levels of synovitis and bone erosion, as well as less myeloperoxidase in synovial tissue. Fluorescence-activated cell sorter analysis revealed that PBD155 treatment affected the expression pattern of adhesion molecules, preventing the upregulation of cells expressing CD11b/CD18.

CONCLUSION

The compounds investigated here represent a novel class of small molecular antiarthritic inhibitors. In our studies, they exerted strong antiinflammatory actions, and therefore they might be suited for disease-modifying treatment of infectious arthritis.

Low number of memory B cells in the salivary glands of patients with primary Sjögren's syndrome

We have previously shown that patients with primary Sjögren's Syndrome (pSS) show a significant reduction of autoantigen specific CD27(+) memory B cells and an abnormally elevated level of autoantibody producing plasma cells in peripheral blood (PB) compared to controls. Because both memory B cells and plasma cells have been detected in salivary glands (SG) of pSS patients, we aimed to study the B cell pattern in SG biopsies. Double immunohistochemical staining of CD20 and CD27 was carried out on paraffin-embedded SG tissue from 10 pSS patients to distinguish CD20(+)/CD27(+) memory B cells, and identify the CD20(+) glandular B cell zones (BCZ). Given that plasma blasts and plasma cells are CD27(++) and CD20(- ), additional CD138 single staining of serial sections allowed the distinction of CD27(++)/CD138(- ) plasma blasts located within the BCZ from CD27(++)/CD138(+) plasma cells that were found mostly on the periphery of the BCZ and also observed interstitially. Both BCZ and the memory B cell populations were then quantified. Contrary to what has been reported earlier through immunoflourescent staining of memory B cells in SG tissue, we have shown that there is a low number of memory B cells located within the glandular BCZ. Plasma blasts and plasma cells, however, were more abundant in the SG. Together our findings suggest that these low numbers of memory B cells in both PB and SG of pSS patients may be the result of activation of these cells into plasma cells at the site of inflammation.

Predictors for the development of non-Hodgkin lymphoma in primary Sjögren's syndrome

Sjögren's syndrome (SS) is a complex autoimmune disease with multi-organ involvement. Its most serious complication is the development of non-Hodgkin lymphoma (NHL). In cohorts of unselected patients with long observation, this lifetime risk is estimated to be 5 to 15%, or approximately 20 times increased risk compared to the general population. Being able to identify patients prone to malignancy would significantly aid in the process of customised treatment and strategy for follow-up. Among the established predictors for lymphoma development in SS, we recognize recurrent or permanent swelling of major salivary glands (SG), lymphadenopathy, cryoglobulinemia, splenomegaly, low complement levels of C4 and C3, lymphopenia, skin vasculitis or palpable purpura, M-component in serum or urine, peripheral neuropathy, glomerulonephritis and elevated beta2-microglobulin. More recent suggestions include some genetic factors, CD4 lymphocytopenia, and ectopic germinal center-like structures in minor SG biopsies. Despite these predictors, there remains a need for defining algorithms for NHL screening and patient follow-up in SS.