The pathogenesis of systemic sclerosis

The role of genetics and epigenetics in the pathogenesis of systemic sclerosis

Systemic sclerosis (SSc) is a complex autoimmune disease of unclear aetiology. A multitude of genetic studies, ranging from candidate-gene studies to genome-wide association studies, have identified a large number of genetic susceptibility factors for SSc and its clinical phenotypes, but the contribution of these factors to disease susceptibility is only modest. However, in an endeavour to explore how the environment might affect genetic susceptibility, epigenetic research into SSc is rapidly expanding. Orchestrated by environmental factors, epigenetic modifications can drive genetically predisposed individuals to develop autoimmunity, and are thought to represent the crossroads between the environment and genetics in SSc. Therefore, in addition to providing a comprehensive description of the current understanding of genetic susceptibility underlying SSc, this Review describes the involvement of epigenetic phenomena, including DNA methylation patterns, histone modifications and microRNAs, in SSc.

The association between vibration and vascular injury in rheumatic diseases: a review of the literature

Vascular manifestations can be seen early in the pathogenesis of inflammatory rheumatic diseases. Animal experiments, laboratory and clinical findings indicated that acute or long-term vibration exposure can induce vascular abnormalities. Recent years, in addition to Raynaud's phenomenon (RP), vibration as a risk factor for other rheumatic diseases has also received corresponding considered. This review is concentrated upon the role of vibration in the disease of systemic sclerosis (SSc). In this review, we are going to discuss the main mechanisms which are thought to be important in pathophysiology of vascular injury under the three broad headings of "vascular", "neural" and "intravascular". Aspects on the vibration and vascular inflammation are briefly discussed. And the epidemiological studies related to vibration studies in SSc and other rheumatic diseases are taken into account.

Dissection of the mechanism of traditional Chinese medical prescription-Yiqihuoxue formula as an effective anti-fibrotic treatment for systemic sclerosis

Background

Systemic sclerosis (SSc) is a connective tissue fibrotic disease for which there is no effective treatment. Traditional Chinese Medicine (TCM), such as the Yiqihuoxue formula used in Shanghai TCM-integrated Hospital, has shown the efficacy of anti-fibrosis in clinical applications. This study was aiming to dissect the anti-fibrotic mechanism of Yiqihuoxue treatment for SSc.

Methods

Bleomycin-induced mice and SSc dermal fibroblasts were treated with Yiqihuoxue decoction; NIH-3T3 fibroblasts were exposed to exogenous TGF-β1, and then cultured with or without Yiqihuoxue decoction. Luciferase reporter gene assay was used to determine the activity of Smad binding element (SBE). Quantitative reverse transcription-polymerase chain reaction (RT-PCR) was used to examine the mRNA levels of extracellular matrix (ECM) genes. The protein levels of type I collagen, Smad3 and phosphorylated-Smad3 (p-Smad3) were detected by western blotting. Student’s t-tests were used to determine the significance of the results.

Results

Bleomycin-induced mice, SSc dermal fibroblasts and TGF-β1-induced NIH/3T3 fibroblasts showed higher levels of ECM gene transcriptions and collagen production. In addition, the phosphorylation level of Smad3 and activity of SBE were significantly increased after exogenous TGF-β1 induction. Whereas, Yiqihuoxue treatment could obviously attenuate fibrosis in bleomycin-induced mice, down regulate ECM gene expressions and collagen production in SSc dermal fibroblasts and TGF-β1-induced NIH/3T3 fibroblasts. Furthermore, the aberrantly high phosphorylation level of Smad3 and activity of SBE in the TGF-β1-induced NIH/3T3 fibroblasts were also dramatically decreased by Yiqihuoxue treatment.

Conclusions

Yiqihuoxue treatment could effectively reduce collagen production via down-regulating the phosphorylation of Smad3 and then the activity of SBE, which are involved in the TGF-β pathway and constitutively activated in the progression of SSc.

DNA hypermethylation of the forkhead box protein 3 (FOXP3) promoter in CD4+ T cells of patients with systemic sclerosis

BACKGROUND

Systemic sclerosis (SSc) is a complex autoimmune disease that involves dysregulation of immune homeostasis. The failure of impaired regulatory T cells (Tregs) to maintain immune homeostasis plays a major role in the development of SSc. Transcriptional silencing of the forkhead box protein 3 gene (FOXP3) via hypermethylation of regulatory regions has been identified as a hallmark of committed Tregs and several autoimmune disorders.

OBJECTIVES

To investigate whether aberrant expression and methylation of FOXP3 occurs in CD4+ T cells of patients with SSc and their roles in the pathogenesis of SSc.

METHODS

FOXP3 expression in CD4+ T cells was measured by real-time quantitative reverse-itranscriptase polymerase chain reaction and western blot. Bisulfite sequencing was performed to determine the methylation status of the FOXP3 proximal promoter sequence. The percentage of Treg cells was estimated by flow cytometry.

RESULTS

Decreased FOXP3 expression was observed in CD4+ T cells from patients with SSc. The methylation levels of the FOXP3 regulatory sequences were elevated and inversely correlated with FOXP3 mRNA expression in patients with SSc. The number of Tregs was significantly reduced in patients with SSc. Treatment of SSc CD4+ T cells with a DNA methylation inhibitor, 5-azacytidine, reduced the mean methylation levels, and enhanced FOXP3 expression and Treg generation. The promoter methylation status and expression level of FOXP3 are significantly associated with disease activity.

CONCLUSIONS

The contribution of the hypermethylation of the FOXP3 promoter to decreased FOXP3 expression and the subsequent quantitative defects of Tregs may mediate the immune dysfunction in SSc.

Dose-escalation of human anti-interferon-α receptor monoclonal antibody MEDI-546 in subjects with systemic sclerosis: a phase 1, multicenter, open label study

Introduction

Type I interferons (IFNs) are implicated in the pathogenesis of systemic sclerosis (SSc). MEDI-546 is an investigational human monoclonal antibody directed against the type I IFN receptor. This Phase 1 study evaluated the safety/tolerability, pharmacokinetics (PK), immunogenicity, and pharmacodynamics (PD) of single and multiple intravenous doses of MEDI-546 in adults with SSc.

Methods

Subjects (≥18 years) with SSc were enrolled in an open-label, dose-escalation study to receive single (0.1, 0.3, 1.0, 3.0, 10.0, or 20.0 mg/kg), or 4 weekly intravenous doses (0.3, 1.0, or 5.0 mg/kg/week) of MEDI-546. Subjects were followed for 12 weeks. Safety assessments included adverse events (AEs), laboratory results, and viral monitoring. Blood samples were collected from all subjects for determination of PK, presence of anti-drug antibodies (ADAs), and expression of type I IFN-inducible genes.

Results

Of 34 subjects (mean age 47.4 years), 32 completed treatment and 33 completed the study. Overall, 148 treatment-emergent AEs (TEAEs) were reported (68.9% mild, 27.7% moderate). TEAEs included one grade 1 infusion reaction (5.0 mg/kg/week multiple dose). Of 4 treatment-emergent serious AEs (skin ulcer, osteomyelitis, vertigo, and chronic myelogenous leukemia (CML)), only CML (1.0 mg/kg/week multiple dose) was considered possibly treatment-related. MEDI-546 exhibited non-linear PK at lower doses. ADAs were detected in 5 subjects; no apparent impact on PK was observed. Peak inhibition of the type I IFN signature in whole blood was achieved within 1 day and in skin after 7 days.

Conclusion

The safety/tolerability, PK, and PD profiles observed in this study support further clinical development of MEDI-546.

Trial Registration

ClinicalTrials.gov NCT00930683

Autoantibodies to angiotensin and endothelin receptors in systemic sclerosis induce cellular and systemic events associated with disease pathogenesis

INTRODUCTION

Vasculopathy, inflammatory fibrosis and functional autoantibodies (Abs) are major manifestations of systemic sclerosis (SSc). Abs directed against the angiotensin II type 1 receptor (AT₁R) and endothelin-1 type A receptor (ETAR) are associated with characteristic disease features including vascular, inflammatory, and fibrotic complications indicating their role in SSc pathogenesis. Therefore, the impact of anti-AT₁R and anti-ETAR Abs on initiation of inflammation and fibrosis was analyzed.

METHODS

Anti-AT₁R and anti-ETAR Ab-positive immunoglobulin G (IgG) from SSc patients (SSc-IgG) was used for experiments. Healthy donor IgG served as a normal control, and AT₁R and ETAR activation was inhibited by antagonists. Protein expression was measured with ELISA, mRNA expression with real time-PCR, endothelial repair with a scratch assay, and collagen expression with immunocytochemistry. Transendothelial neutrophil migration was measured with a culture insert system, and neutrophil ROS activation with immunofluorescence. Neutrophils in bronchoalveolar lavage fluids (BALFs) were analyzed microscopically after passive transfer of SSc-IgG or NC-IgG into naïve C57BL/6J mice. KC plasma levels were quantified by a suspension array system. Histologic analyses were performed by using light microscopy.

RESULTS

Anti-AT₁R and anti-ETAR Ab-positive SSc-IgG induced activation of human microvascular endothelial cells (HMEC-1). Elevated protein and mRNA levels of the proinflammatory chemokine interleukin-8 (IL-8, CXCL8) and elevated mRNA levels of the vascular cell adhesion molecule-1 (VCAM-1) were induced in HMEC-1. Furthermore, activation of HMEC-1 with SSc-IgG increased neutrophil migration through an endothelial cell layer and activation of reactive oxygen species (ROS). SSc-IgG decreased HMEC-1 wound repair and induced type I collagen production in healthy donor skin fibroblasts. Effects of migration, wound repair, and collagen expression were dependent on the Ab-levels. Passive transfer of anti-AT1R and anti-ETAR Ab-positive SSc-IgG into naïve C57BL/6J mice increased neutrophil BALF counts. In parallel, increased levels of the murine functional IL-8 homologue, chemokine KC, were found in the plasma of SSc-IgG-treated mice as well as structural alterations of the lungs.

CONCLUSIONS

We conclude that angiotensin and endothelin-receptor activation via anti-AT₁R and anti-ETAR Abs mediate pathogenic effects, indicating their contribution to pathogenesis of SSc. Therefore, anti-AT₁R and anti-ETAR Abs could provide novel targets for therapeutic intervention in the treatment of SSc.

Cells from the skin of patients with systemic sclerosis secrete chitinase 3-like protein 1

Background

The chitinase-like protein, Chi3L1, is associated with increased fibrotic activity as well as inflammatory processes. The capacity of skin cells from systemic sclerosis (SSc) patients to produce Chi3L1, and the stimulation of its synthesis by cytokines or growth factors known to be associated with SSc, was investigated.

Methods

Cells were isolated from forearm and/or abdomen skin biopsies taken from SSc patients and normal individuals and stimulated with cytokines and growth factors to assess Chi3L1 expression. Chi3L1-expressing cells were characterized by immunohistochemical staining.

Results

Chi3L1 was not secreted by skin cells from normal individuals nor was its synthesis induced by any of the cytokines or growth factors investigated. In contrast, Chi3L1 secretion was induced by OSM or IL-1 in cells from all forearm biopsies of SSc patients, and endogenous secretion in the absence of cytokines was detected in several specimens. Patients with Chi3L1-producing cells at both the arm and abdomen had a disease duration of less than 3 years. Endogenous Chi3L1 production was not a property of the major fibroblast population nor of myofibroblasts, but rather was related to the presence of stem-like cells not present in normal skin. Other cells, however, contributed to the upregulation of Chi3L1 by OSM.

Conclusions

The emergence of cells primed to respond to OSM with increased Chi3L1 production appears to be associated with pathological processes active in SSc.

General significance

The presence of progenitor cells expressing the chilectin Chi3L1 in SSc skin appears to play a role in the initiation of the disease process.

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Cells isolated from the skin of scleroderma patients secrete Chi3L1.

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Chi3L1 production is stimulated by oncostatin M or interleukin 1.

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Patients with Chi3L1 producing cells have disease duration of < 3 years.

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Chi3L1 production is a property of stem-like cells not present in normal skin.

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Other cells contribute to Chi3L1 upregulation by oncostatin M.

[Oral manifestations of systemic sclerosis]

Nous rapportons l'observation d'une jeune femme de 26 ans ayant une sclérodermie systémique diffuse présentant une atteinte bucco-dentaire complexe: microstomie, hyperplasie gingivale, parodontite, dépôts tartriques, caries multiples et chevauchement dentaire antéro-inférieur. Nous discuterons à travers cette observation les manifestations bucco-dentaires de cette connectivite qui sont loin d’être rares mais souvent négligées par les cliniciens malgré leur retentissement fonctionnel majeur. Il convient de surveiller régulièrement l’état bucco-dentaire chez tout patient sclérodermique afin de diagnostiquer précocement ces atteintes. Diagnostiquées à un stade tardif les complications bucco-dentaires de la sclérodermie seront très difficiles à traiter.

Increased risk of acute myocardial infarction in systemic sclerosis: a nationwide population-based study

PURPOSE

Systemic sclerosis is a life-threatening autoimmune disease characterized by vasculopathy, which results in myocardial involvement in an extremely high percentage of patients. Nevertheless, there have been no large-scale epidemiological studies about the risk of acute myocardial infarction in patients with systemic sclerosis. The aims of this study were to evaluate the hazard ratio (HR) and risk factors of acute myocardial infarction in patients with systemic sclerosis, as well as to compare the risks of acute myocardial infarction among systemic sclerosis patients taking different immunosuppressors.

METHODS

The study cohort included 1344 patients with systemic sclerosis and 13,440 (1:10) age-, sex-, and comorbidity-matched controls during the period between 1997 and 2006, from the National Health Insurance Research Database. We compared the risk of acute myocardial infarction between patients with systemic sclerosis and controls and calculated the adjusted HRs for acute myocardial infarction in systemic sclerosis patients taking immunosuppressors and not taking immunosuppressors.

RESULTS

The incidence rates of acute myocardial infarction were 535 and 313 cases per 100,000 person-years for systemic sclerosis cohort and reference cohort, respectively (P <.001, unadjusted). After adjusting for age, sex, and underlying medical diseases on Cox proportional hazards model, systemic sclerosis was found to be an independent risk factor for acute myocardial infarction (HR 2.45). Other risk factors included hypertension (HR 2.08) and diabetes (HR 2.14). The multivariate adjusted HR for acute myocardial infarction did not decrease among the systemic sclerosis patients taking systemic steroids, penicillamine, cyclophosphamide, azathioprine, methotrexate, or cyclosporine.

CONCLUSION

Systemic sclerosis is independently associated with an increased risk of acute myocardial infarction. Immunosuppressors do not lower the risk of acute myocardial infarction in our study.

Role of endothelial to mesenchymal transition in the pathogenesis of the vascular alterations in systemic sclerosis

The pathogenesis of Systemic Sclerosis (SSc) is extremely complex, and despite extensive studies, the exact mechanisms involved are not well understood. Numerous recent studies of early events in SSc pathogenesis have suggested that unknown etiologic factors in a genetically receptive host trigger structural and functional microvascular endothelial cell abnormalities. These alterations result in the attraction, transmigration, and accumulation of immune and inflammatory cells in the perivascular tissues, which in turn induce the phenotypic conversion of endothelial cells and quiescent fibroblasts into activated myofibroblasts, a process known as endothelial to mesenchymal transition or EndoMT. The activated myofibroblasts are the effector cells responsible for the severe and frequently progressive fibrotic process and the fibroproliferative vasculopathy that are the hallmarks of SSc. Thus, according to this hypothesis the endothelial and vascular alterations, which include the phenotypic conversion of endothelial cells into activated myofibroblasts, play a crucial role in the development of the progressive fibrotic process affecting skin and multiple internal organs. The role of endothelial cell and vascular alterations, the potential contribution of endothelial to mesenchymal cell transition in the pathogenesis of the tissue fibrosis, and fibroproliferative vasculopathy in SSc will be reviewed here.

IL-17 in the rheumatologist's line of sight

Over the past decades, the identification of several new cytokines, including interleukin (IL)-17 and IL-23, and of new T helper cell subsets, including Th17 cells, has changed the vision of immunological processes. The IL-17/Th17 pathway plays a critical role during the development of inflammation and autoimmunity, and targeting this pathway has become an attractive strategy for a number of diseases. This review aims to describe the effects of IL-17 in the joint and its roles in the development of autoimmune and inflammatory arthritis. Furthermore, biotherapies targeting directly or indirectly IL-17 in inflammatory rheumatisms will be developed.

Neurologic involvement in scleroderma: a systematic review

OBJECTIVES

To perform a systematic review of neurologic involvement in Systemic sclerosis (SSc) and Localized Scleroderma (LS), describing clinical features, neuroimaging, and treatment.

METHODS

We performed a literature search in PubMed using the following MeSH terms, scleroderma, systemic sclerosis, localized scleroderma, localized scleroderma "en coup de sabre", Parry-Romberg syndrome, cognitive impairment, memory, seizures, epilepsy, headache, depression, anxiety, mood disorders, Center for Epidemiologic Studies Depression (CES-D), SF-36, Beck Depression Inventory (BDI), Beck Anxiety Inventory (BAI), Patient Health Questionnaire-9 (PHQ-9), neuropsychiatric, psychosis, neurologic involvement, neuropathy, peripheral nerves, cranial nerves, carpal tunnel syndrome, ulnar entrapment, tarsal tunnel syndrome, mononeuropathy, polyneuropathy, radiculopathy, myelopathy, autonomic nervous system, nervous system, electroencephalography (EEG), electromyography (EMG), magnetic resonance imaging (MRI), and magnetic resonance angiography (MRA). Patients with other connective tissue disease knowingly responsible for nervous system involvement were excluded from the analyses.

RESULTS

A total of 182 case reports/studies addressing SSc and 50 referring to LS were identified. SSc patients totalized 9506, while data on 224 LS patients were available. In LS, seizures (41.58%) and headache (18.81%) predominated. Nonetheless, descriptions of varied cranial nerve involvement and hemiparesis were made. Central nervous system involvement in SSc was characterized by headache (23.73%), seizures (13.56%) and cognitive impairment (8.47%). Depression and anxiety were frequently observed (73.15% and 23.95%, respectively). Myopathy (51.8%), trigeminal neuropathy (16.52%), peripheral sensorimotor polyneuropathy (14.25%), and carpal tunnel syndrome (6.56%) were the most frequent peripheral nervous system involvement in SSc. Autonomic neuropathy involving cardiovascular and gastrointestinal systems was regularly described. Treatment of nervous system involvement, on the other hand, varied in a case-to-case basis. However, corticosteroids and cyclophosphamide were usually prescribed in severe cases.

CONCLUSIONS

Previously considered a rare event, nervous system involvement in scleroderma has been increasingly recognized. Seizures and headache are the most reported features in LS en coup de sabre, while peripheral and autonomic nervous systems involvement predominate in SSc. Moreover, recently, reports have frequently documented white matter lesions in asymptomatic SSc patients, suggesting smaller branches and perforating arteries involvement.

Assessment of T regulatory cells and expanded profiling of autoantibodies may offer novel biomarkers for the clinical management of systemic sclerosis and undifferentiated connective tissue disease

In order to identify disease biomarkers for the clinical and therapeutic management of autoimmune diseases such as systemic sclerosis (SSc) and undifferentiated connective tissue disease (UCTD), we have explored the setting of peripheral T regulatory (T reg) cells and assessed an expanded profile of autoantibodies in patients with SSc, including either limited (lcSSc) or diffuse (dcSSc) disease, and in patients presenting with clinical signs and symptoms of UCTD. A large panel of serum antibodies directed towards nuclear, nucleolar, and cytoplasmic antigens, including well-recognized molecules as well as less frequently tested antigens, was assessed in order to determine whether different antibody profiles might be associated with distinct clinical settings. Beside the well-recognized association between lcSSc and anti-centromeric or dcSSC and anti-topoisomerase-I antibodies, we found a significative association between dcSSc and anti-SRP or anti-PL-7/12 antibodies. In addition, two distinct groups emerged on the basis of anti-RNP or anti-PM-Scl 75/100 antibody production among UCTD patients. The levels of T reg cells were significantly lower in patients with SSc as compared to patients with UCTD or to healthy controls; in patients with lcSSc, T reg cells were inversely correlated to disease duration, suggesting that their levels may represent a marker of disease progression.

Genetic polymorphisms of FOXP3 in Italian patients with systemic sclerosis

A case control study to evaluate the possible influence of FOXP3 polymorphisms (rs3761548 and rs2280883) in the susceptibility of systemic sclerosis in an Italian Caucasian population. Subgroup analysis was also performed to test association between these SNPs and specific disease phenotypes. The study groups consisted of 467 individuals: 228 patients (194 with limited cutaneous form and 34 with diffuse cutaneous form of the disease) and 239 healthy control subjects. Genotyping was performed by high resolution melting analysis. Genotype distribution and allele frequency of the FOXP3 polymorphisms were analyzed statistically, using χ(2) or Fisher exact test. Single-marker analysis of allelic and genotype frequencies revealed that SNP rs3761548 was not associated with systemic sclerosis susceptibility. Analysis of genotype and allele distributions of the rs2280883 genetic variant was associated, only in female subjects with systemic sclerosis, its limited subtype, and anti-centromere autoantibodies. Although these findings require replication in a larger set and other populations, FOXP3 rs2280883 may represent a novel susceptibility locus for systemic sclerosis in female subjects.

On the respiratory mechanics measured by forced oscillation technique in patients with systemic sclerosis

Background

Pulmonary complications are the most common cause of death and morbidity in systemic sclerosis (SSc). The forced oscillation technique (FOT) offers a simple and detailed approach to investigate the mechanical properties of the respiratory system. We hypothesized that SSc may introduce changes in the resistive and reactive properties of the respiratory system, and that FOT may help the diagnosis of these abnormalities.

Methodology/Principal Findings

We tested these hypotheses in controls (n = 30) and patients with abnormalities classified using spirometry (n = 52) and pulmonary volumes (n = 29). Resistive data were interpreted with the zero-intercept resistance (Ri) and the slope of the resistance (S) as a function of frequency. Reactance changes were evaluated by the mean reactance between 4 and 32 Hz (Xm) and the dynamic compliance (Crs,dyn). The mechanical load was evaluated using the absolute value of the impedance in 4 Hz (Z4Hz). A compartmental model was used to obtain central (R) and peripheral (Rp) resistances, and alveolar compliance (C). The clinical usefulness was evaluated by investigating the area under the receiver operating characteristic curve (AUC). The presence of expiratory flow limitation (EFL) was also evaluated. For the groups classified using spirometry, SSc resulted in increased values in Ri, R, Rp and Z4Hz (p<0.003) and reductions in Crs,dyn, C and Xm (p<0.004). Z4Hz, C and Crs,dyn exhibited a high diagnostic accuracy (AUC>0.90). In groups classified by pulmonary volume, SSc resulted in reductions in S, Xm, C and Crs,dyn (p<0.01). Xm, C and Crs,dyn exhibited adequate diagnostic accuracy (AUC>0.80). It was also observed that EFL is not common in patients with SSc.

Conclusions/Significance

This study provides evidence that the respiratory resistance and reactance are changed in SSc. This analysis provides a useful description that is of particular significance for understanding respiratory pathophysiology and to ease the diagnosis of respiratory abnormalities in these patients.

Interleukin-13-producing CD8+ T cells mediate dermal fibrosis in patients with systemic sclerosis

OBJECTIVE

Fibrosis is a major contributor to morbidity and mortality in systemic sclerosis (SSc). T cells are the predominant inflammatory infiltrate in affected tissue and are thought to produce cytokines that drive the synthesis of extracellular matrix (ECM) proteins by fibroblasts, resulting in excessive fibrosis. We have previously shown that aberrant interleukin-13 (IL-13) production by peripheral blood effector CD8+ T cells from SSc patients correlates with the extent of skin fibrosis. The present study was undertaken to investigate the role of IL-13 production by CD8+ T cells in dermal fibrosis, an early and specific manifestation of SSc.

METHODS

ECM protein production by normal dermal fibroblasts cocultured with SSc CD8+ T cell supernatants was determined by quantitative polymerase chain reaction and Western blotting. Skin-homing receptor expression and IL-13 production by CD8+ T cells in the peripheral blood of SSc patients were measured by flow cytometry. IL-13+ and CD8+ cells in sclerotic skin were identified by immunohistochemistry.

RESULTS

IL-13-producing circulating CD8+ T cells from patients with SSc expressed skin-homing receptors and induced a profibrotic phenotype in normal dermal fibroblasts, which was inhibited by an anti-IL-13 antibody. High numbers of CD8+ T cells and IL-13+ cells were found in the skin lesions of SSc patients, particularly during the early inflammatory phase of the disease.

CONCLUSION

These findings show that IL-13-producing CD8+ T cells are directly involved in modulating dermal fibrosis in SSc. The demonstration that CD8+ T cells homing to the skin early in the course of SSc are associated with accumulation of IL-13 is an important mechanistic contribution to the understanding of the pathogenesis of dermal fibrosis in SSc and may represent a potential target for therapeutic intervention.

Systemic sclerosis endothelial cells recruit and activate dermal fibroblasts by induction of a connective tissue growth factor (CCN2)/transforming growth factor β-dependent mesenchymal-to-mesenchymal transition

OBJECTIVE

Clinical evidence suggests that the vascular abnormalities of systemic sclerosis (SSc) precede the onset of fibrosis, but molecular cues accounting for a possible vascular connection of SSc fibrosis have been elusive, although they have been searched for intensively. Since we had previously shown that connective tissue growth factor (CCN2), endowed with fibroblast-oriented activities, was overexpressed by endothelial cells (ECs) from SSc patients, we undertook this study to investigate its role and mechanisms in fibroblast activation.

METHODS

Normal fibroblasts were challenged with conditioned medium of normal microvascular ECs (MVECs) and MVECs obtained from SSc patients with the diffuse form of the disease. Fibroblast invasion was studied using the Boyden chamber Matrigel assay. Fibroblast activation was evaluated by Western blotting and immunofluorescence of α-smooth muscle actin (α-SMA), vimentin, and type I collagen. Matrix metalloproteinase (MMP) production was evaluated by zymography and reverse transcription-polymerase chain reaction. Signal transduction and activation of the small GTPases RhoA and Rac1 were studied by Western blotting. Inhibition of SSc MVEC conditioned medium-dependent fibroblast activation was obtained by anti-CCN2 antibodies and the transforming growth factor β (TGFβ) antagonist peptide p17.

RESULTS

SSc MVEC CCN2 stimulated fibroblast activation and invasion. Such activities depended on CCN2-induced overexpression of TGFβ and its type I, II, and III receptors combined with overproduction of MMP-2 and MMP-9 gelatinases. All of these effects were reversed by the TGFβ antagonist peptide p17. Motility increase required Rac1 activation and RhoA inhibition and was inhibited by an MMP inhibitor. These features connoted a mesenchymal style of cell invasion. Since fibroblast activation also fostered overexpression of α-SMA, vimentin, and type I collagen, the CCN2-dependent increase in fibroblast activities recapitulated the characteristics of a mesenchymal-to-mesenchymal transition.

CONCLUSION

SSc MVECs recruit and activate dermal fibroblasts by induction of a CCN2/TGFβ-dependent mesenchymal-to-mesenchymal transition.

Acute retinal artery occlusion in systemic sclerosis: a rare manifestation of systemic sclerosis fibroproliferative vasculopathy

OBJECTIVES

To describe three patients with systemic sclerosis (SSc) who developed acute unilateral blindness in the absence of any common etiologic factor for blindness. In one patient, the affected eye required enucleation and was examined histopathologically.

METHODS

Following identification of the first patient with retinal artery occlusion at the Scleroderma Center of Thomas Jefferson University, every patient evaluated at the Center from May 2001 to December 2010 was prospectively assessed for the development of acute unilateral blindness. Two additional cases were identified. Here, we describe the clinical features, laboratory and ancillary examinations of the three patients with SSc who developed acute unilateral blindness and present the histopathological examination of one eye enucleated from one of the patients.

RESULTS

Clinical and angiographic studies were consistent with acute retinal artery occlusion. The histopathological studies showed severe retinal ischemic atrophy and concentric narrowing and fibrosis of small retinal vessels.

CONCLUSIONS

These findings suggest that acute retinal artery occlusion in these patients is a manifestation of the fibroproliferative vasculopathy characteristic of SSc.

Cross-language measurement equivalence of the Center for Epidemiologic Studies Depression (CES-D) scale in systemic sclerosis: a comparison of Canadian and Dutch patients

Objectives

Increasingly, medical research involves patients who complete outcomes in different languages. This occurs in countries with more than one common language, such as Canada (French/English) or the United States (Spanish/English), as well as in international multi-centre collaborations, which are utilized frequently in rare diseases such as systemic sclerosis (SSc). In order to pool or compare outcomes, instruments should be measurement equivalent (invariant) across cultural or linguistic groups. This study provides an example of how to assess cross-language measurement equivalence by comparing the Center for Epidemiologic Studies Depression (CES-D) scale between English-speaking Canadian and Dutch SSc patients.

Methods

The CES-D was completed by 922 English-speaking Canadian and 213 Dutch SSc patients. Confirmatory factor analysis (CFA) was used to assess the factor structure in both samples. The Multiple-Indicator Multiple-Cause (MIMIC) model was utilized to assess the amount of differential item functioning (DIF).

Results

A two-factor model (positive and negative affect) showed excellent fit in both samples. Statistically significant, but small-magnitude, DIF was found for 3 of 20 items on the CES-D. The English-speaking Canadian sample endorsed more feeling-related symptoms, whereas the Dutch sample endorsed more somatic/retarded activity symptoms. The overall estimate in depression scores between English and Dutch was not influenced substantively by DIF.

Conclusions

CES-D scores from English-speaking Canadian and Dutch SSc patients can be compared and pooled without concern that measurement differences may substantively influence results. The importance of assessing cross-language measurement equivalence in rheumatology studies prior to pooling outcomes obtained in different languages should be emphasized.

Systemic sclerosis

This review updates the clinician on the pathogenesis, differential diagnosis and spectrum of disease in systemic sclerosis. The wide range of current therapeutic options and future targeted molecular therapies are also explored.

Systemic sclerosis without antinuclear antibodies or Raynaud's phenomenon: a multicentre study in the prospective EULAR Scleroderma Trials and Research (EUSTAR) database

OBJECTIVE

To assess patients with SSc who present without circulating ANAs or RP.

METHODS

Five thousand three hundred and ninety patients who fulfilled the ACR criteria for SSc and were enrolled in the EULAR Scleroderma Trials and Research (EUSTAR) database were screened for the absence of both RP and circulating ANA. To differentiate SSc from its mimics, additional information was gathered using a standardized questionnaire.

RESULTS

Five thousand three hundred and seventy-eight (99.8%) of the 5390 SSc patients in the EUSTAR database had either detectable ANA or a history of RP. Twelve (0.2%) patients lacked both circulating ANA and RP. Details of the medical history could be obtained for seven patients. Three cases were compatible with ANA-negative and RP-negative SSc and were not typical of any known SSc mimic. Four patients had a malignancy: two had breast cancer, one had multiple myeloma with possible scleromyxoedema and one had bladder carcinoma. There was no temporal relationship between the onset of skin fibrosis and that of the tumour. Although no patient with confirmed nephrogenic systemic fibrosis was identified among the cases of ANA-negative and RP-negative SSc, the presentation of one patient could be compatible with that of nephrogenic systemic fibrosis other than for the absence of chronic kidney disease or of known prior gadolinium exposure.

CONCLUSION

We have identified a very small subgroup of SSc patients who lack both circulating ANA and RP, none of whom fulfils the diagnostic criteria for any known SSc mimic. Prospective studies are needed to elucidate the clinical presentation, evolution and outcome of such patients.

Implication of IL-2/IL-21 region in systemic sclerosis genetic susceptibility

OBJECTIVE

The interleukin 2 (IL-2) and interleukin 21 (IL-21) locus at chromosome 4q27 has been associated with several autoimmune diseases, and both genes are related to immune system functions. The aim of this study was to evaluate the role of the IL-2/IL-21 locus in systemic sclerosis (SSc).

PATIENTS AND METHODS

The case control study included 4493 SSc Caucasian patients and 5856 healthy controls from eight Caucasian populations (Spain, Germany, The Netherlands, USA, Italy, Sweden, UK and Norway). Four single nucleotide polymorphisms (rs2069762, rs6822844, rs6835457 and rs907715) were genotyped using TaqMan allelic discrimination assays.

RESULTS

We observed evidence of association of the rs6822844 and rs907715 variants with global SSc (pc=6.6E-4 and pc=7.2E-3, respectively). Similar statistically significant associations were observed for the limited cutaneous form of the disease. The conditional regression analysis suggested that the most likely genetic variation responsible for the association was the rs6822844 polymorphism. Consistently, the rs2069762A-rs6822844T-rs6835457G-rs907715T allelic combination showed evidence of association with SSc and limited cutaneous SSc subtype (pc=1.7E-03 and pc=8E-4, respectively).

CONCLUSIONS

These results suggested that the IL-2/IL-21 locus influences the genetic susceptibility to SSc. Moreover, this study provided further support for the IL-2/IL-21 locus as a common genetic factor in autoimmune diseases.

High prevalence of primary biliary cirrhosis and disease-associated autoantibodies in Japanese patients with systemic sclerosis

OBJECTIVE

To investigate the prevalence of primary biliary cirrhosis (PBC) and PBC-associated autoantibodies in Japanese systemic sclerosis (SSc) patients.

METHODS

Clinical data from 225 Japanese SSc patients were retrospectively obtained. Serum samples from these patients were examined for PBC-associated autoantibodies, anti-mitochondrial M2 antibodies (AMA), anti-sp100 antibodies (anti-sp100), and anti-gp210 antibodies (anti-gp210) by enzyme-linked immunosorbent assay.

RESULTS

Of 225 patients, 37 (16.4%) had AMA, 13 (5.8%) had anti-sp100, and 3 (1.3%) had anti-gp210. Three patients were positive for both AMA and anti-sp100, and 2 were positive for both AMA and anti-gp210. PBC was found in 22 (9.8%) patients positive for AMA with or without anti-sp100 or anti-gp210, but not in those with anti-sp100 or anti-gp210 without AMA. Furthermore, 13 patients lacking these three antibodies were diagnosed with or suspected of PBC by liver biopsy and/or their clinical manifestation. Multivariable analysis revealed that AMA and anti-centromere antibodies were independently associated with PBC in SSc patients, while anti-sp100 and anti-gp210 were not.

CONCLUSIONS

This study has demonstrated even higher prevalence of both PBC-associated autoantibodies and PBC in the Japanese SSc population than in the Caucasian SSc population. AMA and anti-centromere antibodies are likely to indicate increasing risk of PBC in SSc patients.

Systemic sclerosis-dermatological aspects. Part 1: Pathogenesis, epidemiology, clinical findings

Systemic sclerosis is a chronic inflammatory multiorgan disease belonging to the group of collagen-vascular disorders. With a prevalence of 10/100,000 inhabitants it may be regarded a rather rare disease. Its etiology and pathogenesis have still not been elucidated in detail, especially with regard to the differential involvement of skin and the cause of the clinically heterogeneous disease courses. Various components of the vasculature, connective tissue as well as the immune system are involved in a yet unknown sequence and significance. Patients need to be cared for in an interdisciplinary fashion depending on the individual organ involvement. Apart from the skin, the heart, kidneys and lungs are mainly affected in addition to frequent gastrointestinal and musculoskeletal symptoms. Clinically two distinct subsets may be separated, acral (also termed limited) and diffuse scleroderma, which are characterized by anti-centromere and anti-Scl-70/topoisomerase-1 antibodies, respectively. Recent data demonstrate a poor prognosis even in limited disease when pulmonary arterial hypertension develops at an early stage. In diffuse disease sudden and rapid onset will result in a sclerosis of major internal organs and early death in many cases.

Sphingosine-1-phosphate: a Janus-faced mediator of fibrotic diseases

Sphingosine-1-phosphate (S1P) is a pleiotropic lipid mediator that acts either on G protein-coupled S1P receptors on the cell surface or via intracellular target sites. In addition to the well established effects of S1P in angiogenesis, carcinogenesis and immunity, evidence is now continuously accumulating which demonstrates that S1P is an important regulator of fibrosis. The contribution of S1P to fibrosis is of a Janus-faced nature as S1P exhibits both pro- and anti-fibrotic effects depending on its site of action. Extracellular S1P promotes fibrotic processes in a S1P receptor-dependent manner, whereas intracellular S1P has an opposite effect and dampens a fibrotic reaction by yet unidentified mechanisms. Fibrosis is a result of chronic irritation by various factors and is defined by an excess production of extracellular matrix leading to tissue scarring and organ dysfunction. In this review, we highlight the general effects of extracellular and intracellular S1P on the multistep cascade of pathological fibrogenesis including tissue injury, inflammation and the action of pro-fibrotic cytokines that stimulate ECM production and deposition. In a second part we summarize the current knowledge about the involvement of S1P signaling in the development of organ fibrosis of the lung, kidney, liver, heart and skin. Altogether, it is becoming clear that targeting the sphingosine kinase-1/S1P signaling pathway offers therapeutic potential in the treatment of various fibrotic processes. This article is part of a Special Issue entitled Advances in Lysophospholipid Research.

Symptoms and esophageal motility based on phenotypic findings of scleroderma

Scleroderma esophagus is characterized by ineffective peristalsis and reduced esophageal sphincter pressure. Esophageal disease in scleroderma can precede cutaneous manifestations and has been associated with Raynaud's phenomenon (RP) and pulmonary fibrosis (PF). The objective of the study is to evaluate the impact of cutaneous findings, RP, and PF on demographics, symptoms, and esophageal motility in patients with scleroderma. Scleroderma patients with esophageal involvement were included after review of esophageal manometries and charts over a 6-year period. High-resolution esophageal manometry was performed. Patients completed a symptom questionnaire. The study enrolled 28 patients (22 females; mean age 50.3 ± 12.8 years) with scleroderma esophagus. Patients without skin involvement (n= 12) reported more severe heartburn (P= 0.02), while those with cutaneous findings (n= 16) had more frequent dysphagia with solids (P= 0.02). Patients with RP (n= 22) had lower amplitude of distal esophageal contractions (P= 0.01) than those without RP (n= 6). Patients with PF (n= 11) reported more severe coughing and wheezing (both P= 0.03) than those without lung disease (n= 17). This study highlights subgroups of patients with scleroderma esophagus according to phenotypic findings of dermatologic changes, RP, and PF. Heartburn and dysphagia are important symptoms that may be associated with different stages of disease progression based on skin changes in scleroderma. RP was associated with greater esophageal dysmotility. Coughing and wheezing were more severe in patients with PF.

Evidence that deletion at FCGR3B is a risk factor for systemic sclerosis

There is increasing evidence that gene copy number (CN) variation influences clinical phenotype. The low-affinity Fc receptor 3B (FCGR3B) located in the FCGR gene cluster is a CN polymorphic gene involved in the recruitment of polymorphonuclear neutrophils to sites of inflammation and their activation. Given the genetic overlap between systemic lupus erythematosus and systemic sclerosis (SSc) and the strong evidence for FCGR3B CN in the pathology of SLE, we hypothesised that FCGR3B gene dosage influences susceptibility to SSc. We obtained FCGR3B deletion status in 777 European Caucasian cases and 1000 controls. There was an inverse relationship between FCGR3B CN and disease susceptibility. CN of ≤ 1 was a significant risk factor for SSc (OR=1.55 (1.13-2.14), P=0.007) relative to CN ≥ 2. Although requiring replication, these results suggest that impaired immune complex clearance arising from FCGR3B deficiency contributes to the pathology of SSc, and FCGR3B CN variation is a common risk factor for systemic autoimmunity.

[Critical limb ischemia in systemic sclerosis]

Vascular complications are common in systemic sclerosis (SSc). Critical limb ischemia leading to gangrene or amputation occurs in more than 10% of these patients and hence is a common emergency. This report highlights the different pathogenetic mechanisms leading to critical ischemic events and provides guidance for the diagnosis and therapy. Apart from SSc-associated vasculopathy and peripheral arterial disease, thromboembolic events and rarely also vasculitis may cause critical limb ischemia. An interdisciplinary approach to the diagnosis and therapy of these lesions is mandatory. Therapy goals are the prevention of further ischemia and, if possible, revascularization as well as optimal pain management.

A prospective observational study of mycophenolate mofetil treatment in progressive diffuse cutaneous systemic sclerosis of recent onset

OBJECTIVE

A prospective observational study of mycophenolate mofetil (MMF) treatment in patients with diffuse progressive cutaneous systemic sclerosis (SSc) of recent onset.

METHODS

Twenty-five previously untreated consecutive patients with recent-onset (< 24 mo) diffuse progressive cutaneous SSc received MMF as the only disease-modifying therapy. Modified Rodnan skin score (mRSS) and affected body surface area (BSA) were compared from initiation of MMF to study end. Pulmonary function tests performed at the same institution before therapy and at study end were available in 15 patients. Histopathology and real-time PCR assessment of fibrosis-related gene expression were performed before and after treatment in skin biopsies from 3 patients.

RESULTS

At 18.2 ± 8.73 months of MMF therapy (median 2000 mg/day) the mRSS decreased from 24.56 ± 8.62 to 14.52 ± 10.9 (p = 0.0004) and the affected BSA from 36% ± 16% to 14% ± 13.3% (p = 0.00001). Pulmonary function tests remained stable from initiation of MMF to the end of the study. Skin histopathology showed a remarkable reduction in accumulation of fibrotic tissue. Real-time PCR of skin biopsies demonstrated a marked decrease in expression of fibrosis-related genes.

CONCLUSION

Patients with diffuse progressive cutaneous SSc of recent onset treated with MMF experienced marked improvement in skin involvement and stabilization of pulmonary function. Skin biopsies from 3 patients demonstrated histopathological improvement and decreased expression of fibrosis-related genes.

High prevalence of primary biliary cirrhosis and disease-associated autoantibodies in Japanese patients with systemic sclerosis

OBJECTIVE

To investigate the prevalence of primary biliary cirrhosis (PBC) and PBC-associated autoantibodies in Japanese systemic sclerosis (SSc) patients.

METHODS

Clinical data from 225 Japanese SSc patients were retrospectively obtained. Serum samples from these patients were examined for PBC-associated autoantibodies, anti-mitochondrial M2 antibodies (AMA), anti-sp100 antibodies (anti-sp100), and anti-gp210 antibodies (anti-gp210) by enzyme-linked immunosorbent assay.

RESULTS

Of 225 patients, 37 (16.4%) had AMA, 13 (5.8%) had anti-sp100, and 3 (1.3%) had anti-gp210. Three patients were positive for both AMA and anti-sp100, and 2 were positive for both AMA and anti-gp210. PBC was found in 22 (9.8%) patients positive for AMA with or without anti-sp100 or anti-gp210, but not in those with anti-sp100 or anti-gp210 without AMA. Furthermore, 13 patients lacking these three antibodies were diagnosed with or suspected of PBC by liver biopsy and/or their clinical manifestation. Multivariable analysis revealed that AMA and anti-centromere antibodies were independently associated with PBC in SSc patients, while anti-sp100 and anti-gp210 were not.

CONCLUSIONS

This study has demonstrated even higher prevalence of both PBC-associated autoantibodies and PBC in the Japanese SSc population than in the Caucasian SSc population. AMA and anti-centromere antibodies are likely to indicate increasing risk of PBC in SSc patients.

Pressure and pain in systemic sclerosis/scleroderma--an evaluation of a simple intervention (PISCES): randomised controlled trial protocol

Background

Foot problems associated with Systemic Sclerosis (SSc)/Scleroderma have been reported to be both common and disabling. There are only limited data describing specifically, the mechanical changes occurring in the foot in SSc. A pilot project conducted in preparation for this trial confirmed the previous reports of foot related impairment and reduced foot function in people with SSc and demonstrated a link to mechanical etiologies. To-date there have been no formal studies of interventions directed at the foot problems experienced by people with Systemic Sclerosis. The primary aim of this trial is to evaluate whether foot pain and foot-related health status in people with Systemic Sclerosis can be improved through the provision of a simple pressure-relieving insole.

Methods

The proposed trial is a pragmatic, multicenter, randomised controlled clinical trial following a completed pilot study. In four participating centres, 140 consenting patients with SSc and plantar foot pain will be randomised to receive either a commercially available pressure relieving and thermally insulating insole, or a sham insole with no cushioning or thermal properties. The primary end point is a reduction in pain measured using the Foot Function Index Pain subscale, 12 weeks after the start of intervention. Participants will complete the primary outcome measure (Foot Function Index pain sub-scale) prior to randomisation and at 12 weeks post randomisation. Secondary outcomes include participant reported pain and disability as derived from the Manchester Foot Pain and Disability Questionnaire and plantar pressures with and without the insoles in situ.

Discussion

This trial protocol proposes a rigorous and potentially significant evaluation of a simple and readily provided therapeutic approach which, if effective, could be of a great benefit for this group of patients.

Trial registration number

ISRCTN: ISRCTN02824122

Neurologic involvement in scleroderma en coup de sabre

Localized scleroderma is a rare disease, characterized by sclerotic lesions. A variety of presentations have been described, with different clinical characteristics and specific prognosis. In scleroderma en coup de sabre (LScs) the atrophic lesion in frontoparietal area is the disease hallmark. Skin and subcutaneous are the mainly affected tissues, but case reports of muscle, cartilage, and bone involvement are frequent. These cases pose a difficult differential diagnosis with Parry-Romberg syndrome. Once considered an exclusive cutaneous disorder, the neurologic involvement present in LScs has been described in several case reports. Seizures are most frequently observed, but focal neurologic deficits, movement disorders, trigeminal neuralgia, and mimics of hemiplegic migraines have been reported. Computed tomography and magnetic resonance imaging have aided the characterization of central nervous system lesions, and cerebral angiograms have pointed to vasculitis as a part of disease pathogenesis. In this paper we describe the clinical and radiologic aspects of neurologic involvement in LScs.

Novel imaging techniques for diffuse myocardial fibrosis

Diffuse myocardial fibrosis (DMF) is an important marker in many cardiac diseases, but its utility has been limited by the need for biopsy for its assessment. An accurate noninvasive method for DMF assessment could transform cardiology. This review explores the basic biology of DMF and then discusses the ability of various cardiac imaging modalities to evaluate this variable, speculating on how this area of research may develop over the next few years.

A GWAS follow-up study reveals the association of the IL12RB2 gene with systemic sclerosis in Caucasian populations

A single-nucleotide polymorphism (SNP) at the IL12RB2 locus showed a suggestive association signal in a previously published genome-wide association study (GWAS) in systemic sclerosis (SSc). Aiming to reveal the possible implication of the IL12RB2 gene in SSc, we conducted a follow-up study of this locus in different Caucasian cohorts. We analyzed 10 GWAS-genotyped SNPs in the IL12RB2 region (2309 SSc patients and 5161 controls). We then selected three SNPs (rs3790567, rs3790566 and rs924080) based on their significance level in the GWAS, for follow-up in an independent European cohort comprising 3344 SSc and 3848 controls. The most-associated SNP (rs3790567) was further tested in an independent cohort comprising 597 SSc patients and 1139 controls from the USA. After conditional logistic regression analysis of the GWAS data, we selected rs3790567 [P(MH)= 1.92 × 10(-5) odds ratio (OR) = 1.19] as the genetic variant with the firmest independent association observed in the analyzed GWAS peak of association. After the first follow-up phase, only the association of rs3790567 was consistent (P(MH)= 4.84 × 10(-3) OR = 1.12). The second follow-up phase confirmed this finding (P(χ2) = 2.82 × 10(-4) OR = 1.34). After performing overall pooled-analysis of all the cohorts included in the present study, the association found for the rs3790567 SNP in the IL12RB2 gene region reached GWAS-level significant association (P(MH)= 2.82 × 10(-9) OR = 1.17). Our data clearly support the IL12RB2 genetic association with SSc, and suggest a relevant role of the interleukin 12 signaling pathway in SSc pathogenesis.

Polymorphisms in the Interleukin 4, Interleukin 13, and Corresponding Receptor Genes Are Not Associated with Systemic Sclerosis and Do Not Influence Gene Expression

Objective.

Polymorphisms in the genes encoding interleukin 4 (IL4), interleukin 13 (IL13), and their corresponding receptors have been associated with multiple immune-mediated diseases. Our aim was to validate these previous observations in patients with systemic sclerosis (SSc) and scrutinize the effect of the polymorphisms on gene expression in various populations of peripheral blood leukocytes.

Methods.

We genotyped a cohort of 2488 patients with SSc and 2246 healthy controls from The Netherlands, Spain, United Kingdom, Italy, Germany, and France. Taqman assays were used to genotype single-nucleotide polymorphisms (SNP) in the following genes: (1) IL4 (−590C>T/rs2243250); (2) IL4 receptor alpha (IL4RA) (Q576R/rs1801275); (3) IL13 (R130Q/rs20541 and −1112C>T/rs1800925); and (4) IL13RA1 (43163G>A/rs6646259). The effect of these polymorphisms on expression of the corresponding genes was assessed using quantitative RT-PCR on RNA derived from peripheral blood B cells, T cells, plasmacytoid dendritic cells, monocytes, and myeloid dendritic cells. We investigated whether these polymorphisms influenced development of pulmonary complications over 15 years in patients with SSc.

Results.

None of the investigated polymorphisms was associated with SSc or any SSc clinical subtype. We did not observe any effect on transcript levels in the cell subtypes or on development of pulmonary complications.

Conclusion.

Our data showed that polymorphisms in IL4, IL13, and their receptors do not play a role in SSc and do not influence the expression of their corresponding transcript in peripheral blood cells.

Endothelin Receptor Antagonists for the Treatment of Raynaud's Phenomenon and Digital Ulcers in Systemic Sclerosis

Systemic sclerosis is a connective tissue disease characterized by fibrosis of the skin, internal organs, and widespread vasculopathy. Raynaud's phenomenon and digital ulcers are vascular manifestations of this disease and cause significant morbidity. Current treatments are only moderately effective in reducing the severity of Raynaud's in a portion of patients and typically do not lead to substantial benefit in terms of the healing or prevention of digital ulcers. Several studies have evaluated the efficacy of targeting the vasoconstrictor endothelin-1 for the treatment of systemic sclerosis-associated vascular disease. The purpose of this paper is to summarize the published studies and case reports evaluating the efficacy of endothelin receptor antagonists in the treatment of Raynaud's phenomenon and digital ulcers associated with systemic sclerosis.

Blocking TGFβ via Inhibition of the αvβ6 Integrin: A Possible Therapy for Systemic Sclerosis Interstitial Lung Disease

Interstitial lung disease (ILD) is a commonly encountered complication of systemic sclerosis (SSc) and accounts for a significant proportion of SSc-associated morbidity and mortality. Its pathogenesis remains poorly understood, and therapies that treat SSc ILD are suboptimal, at best. SSc ILD pathogenesis may share some common mechanisms with other fibrotic lung diseases, in which dysregulation of lung epithelium can contribute to pathologic fibrosis via recruitment or in situ generation and activation of fibroblasts. TGFβ, a master regulator of fibrosis, is tightly regulated in the lung by the integrin αvβ6, which is expressed at low levels on healthy alveolar epithelial cells but is highly induced in the setting of lung injury or fibrosis. Here we discuss the biology of αvβ6 and present this integrin as a potentially attractive target for inhibition in the setting of SSc ILD.

Novel identification of the IRF7 region as an anticentromere autoantibody propensity locus in systemic sclerosis

OBJECTIVE

Systemic sclerosis (SSc) and systemic lupus erythematosus (SLE) are related chronic autoimmune diseases of complex aetiology in which the interferon (IFN) pathway plays a key role. Recent studies have reported an association between IRF7 and SLE which confers a risk to autoantibody production. A study was undertaken to investigate whether the IRF7 genomic region is also involved in susceptibility to SSc and the main clinical features.

METHODS

Two case-control sets of Caucasian origin from the USA and Spain, comprising a total of 2316 cases of SSc and 2347 healthy controls, were included in the study. Five single nucleotide polymorphisms (SNPs) in the PHRF1-IRF7-CDHR5 locus were genotyped using TaqMan allelic discrimination technology. A meta-analysis was performed to test the overall effect of these genetic variants on SSc.

RESULTS

Four out of five analysed SNPs were significantly associated with the presence of anticentromere autoantibodies (ACA) in the patients with SSc in the combined analysis (rs1131665: p(FDR)=6.14 × 10(-4), OR=0.78; rs4963128: p(FDR)=6.14 × 10(-4), OR=0.79; rs702966: p(FDR)=3.83 × 10(-3), OR=0.82; and rs2246614: p(FDR)=3.83 × 10(-3), OR=0.83). Significant p values were also obtained when the disease was tested globally; however, the statistical significance was lost when the ACA-positive patients were excluded from the study, suggesting that these associations rely on ACA positivity. Conditional logistic regression and allelic combination analyses suggested that the functional IRF7 SNP rs1131665 is the most likely causal variant.

CONCLUSIONS

The results show that variation in the IRF7 genomic region is associated with the presence of ACA in patients with SSc, supporting other evidence that this locus represents a common risk factor for autoantibody production in autoimmune diseases.