Autoantibodies in systemic sclerosis and fibrosing syndromes: clinical indications and relevance

Development of Pulmonary Hypertension in Over One-Third of Patients With Th/To Antibody-Positive Scleroderma in Long-Term Follow-Up

OBJECTIVE

This study was undertaken to describe clinical manifestations in patients with Th/To antibody-positive systemic sclerosis (SSc) during long-term follow-up.

METHODS

We performed a case-control study involving anti-Th/To antibody-positive patients with SSc who were newly referred to the University of Pittsburgh Medical Center and the Pittsburgh Scleroderma Center from 1980 to 2015. For every case, 2 anti-Th/To antibody-negative SSc patients (the first 2 consecutively seen after a case) were used as controls. Long-term disease manifestations and survival were then compared between cases and controls.

RESULTS

A total of 204 anti-Th/To antibody-positive SSc patients and 408 controls were identified. The cohort had a mean ± SD age of 52 ± 12.9 years, and 76% of individuals were women. Anti-Th/To antibody-positive patients more often presented without skin thickening (P < 0.0001) and had a higher rate of pulmonary hypertension (PH) (P < 0.0001) and interstitial lung disease (P = 0.05) compared to anti-Th/To antibody-negative SSc controls. Anti-Th/To antibody-positive SSc patients also had less frequent muscle and joint involvement than anti-Th/To antibody-negative SSc controls (P < 0.0001). After a median clinical follow-up period of 6.1 years (interquartile range 2.4-12.7), 38% of anti-Th/To-positive patients had developed PH compared to 15% of anti-Th/To antibody-negative SSc controls (P < 0.0001). The rate of PH classified as World Health Organization (WHO) Group 1 pulmonary arterial hypertension [PAH] was 23% in anti-Th/To-positive patients compared to 9% in anti-Th/To antibody-negative SSc controls (P < 0.0001). After adjusting for age and sex, anti-Th/To antibody positivity was associated with a hazard ratio (HR) of 3.3 (95% confidence interval 2.3-4.9) for increased risk of developing PH at 10 years of follow-up from the first scleroderma center visit.

CONCLUSION

This is the largest cohort of patients with anti-Th/To antibody-positive SSc with long-term follow-up data. The very high rate (38%) and associated independent risk of anti-Th/To antibody-positive patients developing PH in follow-up, particularly in WHO Group 1 PAH patients, is striking. Patients presenting with limited skin involvement should be tested for Th/To antibodies, and if present, careful monitoring for PH is warranted.

Clinical impact and prognosis of cryoglobulinemia and cryofibrinogenemia in systemic sclerosis

INTRODUCTION

An association of systemic sclerosis (SSc) with cryoglobulin and/or cryofibrinogenemia has been described. However, clinical, biological, morphological and prognostic implications are unknown. The objective of this study was to describe the phenotype and evaluate the prognosis of cryoglobulinemia and/or cryofibrinogenemia in the progression of SSc.

MATERIALS AND METHODS

Patients were included from the Systemic Scleroderma Toulouse Cohort (SSTC), between June 1, 2005 and May 31, 2018, and underwent a measurement of a cryoglobulin and/or cryofibrinogen in immunology laboratory at the Toulouse University Hospital Center. Patients with and without cryoglobulinemia >50 mg/l and patients with and without cryofibrinogenemia were compared to identified the impact of cryoprcipitate on the phenotype. Mortality based on cryoprecipitate was explored.

RESULTS

166 patients were included in the study. 43.3% and 46.6% had a cryoglobulinemia >50 mg/l and cryofibrinogenemia, respectively. Cryoglobulin >50 mg was not associated with microvascular damage. Cryoglobulin does not influence the phenotype. 5-and 10-years survival were 97.6% and 88.8% respectively in patients with cryoglobulinemia >50 mg/l versus 91.9% and 78.4% in patients without cryoglobulin>50 mg/l. 10-years survival was better for patients with cryoglobulinemia >50 mg/l (log-rank 0.0363). Cryofibrinogenemia was not associated with neoplasia, any clinical (in particular ischemic damage), biological or morphological features. Cryofibrinogenemia had no influence on the mortality of these patients.

CONCLUSION

Cryoglobulinemia and cryofibrinogenemia are frequent in SSc. The presence of cryoprecipitate (cryoglobulin or cryofibrinogen) not influence the phenotype and has not associated with a poor survival.

Clinical characteristics associated with small airways disease in systemic sclerosis

Objective:

Pulmonary manifestations of systemic sclerosis are a major cause of morbidity and mortality. Small airways disease can cause dyspnea and pulmonary function test abnormalities. We aimed to determine the prevalence of small airways disease and describe the characteristics associated with small airways disease in a cohort of systemic sclerosis patients.

Methods:

We performed a retrospective cohort study of adults with systemic sclerosis who met American College of Rheumatology/European League Against Rheumatism 2013 classification criteria and were evaluated at our institution between November 2000 and November 2015. Patients with prior lung transplantation were excluded. Small airways disease was defined as the presence of one or more of the following: airway-centered fibrosis on surgical lung biopsy, forced expiratory volume at 25–75% ⩽ 50% on pulmonary function tests, and/or high-resolution computed tomography scan of the chest with bronchiolitis, mosaic attenuation, or air trapping on expiratory views. The primary outcome was small airways disease diagnosis. We performed multivariable logistic regression to determine the association of clinical variables with small airways disease.

Results:

One-hundred thirty-six systemic sclerosis patients were included; 55 (40%) had small airways disease. Compared to those without small airways disease, a significantly greater proportion of those with small airways disease had interstitial lung disease, chronic obstructive pulmonary disease, pulmonary hypertension, and gastroesophageal reflux disease. On multivariable analysis, pulmonary hypertension (odds ratio = 2.91, 95% confidence interval = 1.11–7.65, p-value = 0.03), gastroesophageal reflux disease (odds ratio = 2.70, 95% confidence interval = 1.08–6.79, p-value = 0.034), and anti-topoisomerase I (anti-Scl-70) antibody positivity (odds ratio = 0.42, 95% confidence interval = 0.19–0.93, p-value = 0.033) were associated with diagnosis of small airways disease.

Conclusion:

Small airways disease is prevalent among systemic sclerosis patients; those with pulmonary hypertension or gastroesophageal reflux disease may have a higher risk of small airways disease.

Anti-Polymyositis/Scl Antibodies in Systemic Sclerosis: Clinical Associations in a Multicentric Spanish Cohort and Review of the Literature

OBJECTIVES

To assess the clinical profile of patients with anti-polymyositis/Scl (PM/Scl) antibodies in a cohort of Spanish patients with systemic sclerosis.

METHODS

From the Spanish Scleroderma Study Group database, we selected patients in whom PM/Scl antibodies had been tested. We compared demographic, clinical, laboratory, and survival data between patients with and without PM/Scl antibodies.

RESULTS

Seventy-two of 947 patients (7.6%) tested positive for PM/Scl antibodies. Patients with PM/Scl antibodies presented initially with more puffy fingers and arthralgias but less Raynaud phenomenon. Regarding cumulative manifestations, myositis and arthritis were more prevalent in patients with PM/Scl antibodies, as well as pulmonary fibrosis. On the contrary, patients with PM/Scl antibodies had less pulmonary hypertension. No difference in terms of survival at 5 and 10 years was noticed between the 2 groups.

CONCLUSIONS

In systemic sclerosis patients from Spain, PM/Scl antibodies are associated with a distinct clinical profile. However, PM/Scl antibodies did not influence survival.

Sine scleroderma, limited cutaneous, and diffused cutaneous systemic sclerosis survival and predictors of mortality

BACKGROUND

Systemic sclerosis (SSc) is associated with a variability of mortality rates in the literature.

OBJECTIVE

To determine the mortality and its predictors in a long-term follow-up of a bi-centric cohort of SSc patients.

METHODS

A retrospective observational study by systematically analyzing the medical records of patients diagnosed with SSc in Toulouse University Hospital and Ducuing Hospital. Standardized Mortality Ratio (SMR), mortality at 1, 3, 5, 10, and 15 years of disease and causes of death were described. Predictors of mortality using Cox regression were assessed.

RESULTS

Three hundred seventy-five patients were included: 63 with diffuse cutaneous SSc, 279 with limited cutaneous SSc, and 33 with sine scleroderma. The SMR ratio was 1.88 (95% CI 1.46-1.97). The overall survival rates were 97.6% at 1 year, 93.4% at 3 years, 87.1% at 5 years, 77.9% at 10 years, and 61.3% at 15 years. Sixty-nine deaths were recorded. 46.4% were SSc related deaths secondary to interstitial lung disease (ILD) (34.4%), pulmonary hypertension (31.2%), and digestive tract involvement (18.8%). 53.6% were non-related to SSc: cardiovascular disorders (37.8%) and various infections (35.1%) largely distanced those from cancer (13.5%). Four significant independent predictive factors were identified: carbon monoxide diffusing capacity (DLCO) < 70% (HR=3.01; p=0.0053), C-reactive protein (CRP) >5 mg/l (HR=2.13; p=0.0174), cardiac involvement (HR=2.86; p=0.0012), and the fact of being male (HR=3.25; p=0.0004).

CONCLUSION

Long-term data confirmed high mortality of SSc. Male sex, DLCO <70%, cardiac involvement, and CRP> 5mg/l were identified as independent predictors of mortality.

Clinical and Histopathological Features of Scleroderma-like Disorders: An Update

Scleroderma-like disorders include a set of entities involving cutis, subcutis and, sometimes, even muscular tissue, caused by several pathogenetic mechanisms responsible for different clinical–pathological pictures. The absence of antinuclear antibodies (ANA), Raynaud’s phenomenon and capillaroscopic anomalies constitutes an important element of differential diagnosis with systemic sclerosis. When scleroderma can be excluded, on the basis of the main body sites, clinical evolution, any associated pathological conditions and specific histological features, it is possible to make a correct diagnosis.

Safety and Efficacy of B-Cell Depletion with Rituximab for the Treatment of Systemic Sclerosis-associated Pulmonary Arterial Hypertension: A Multicenter, Double-Blind, Randomized, Placebo-controlled Trial

Rationale: Systemic sclerosis (SSc)-pulmonary arterial hypertension (PAH) is one of the most prevalent and deadly forms of PAH. B cells may contribute to SSc pathogenesis. Objectives: We investigated the safety and efficacy of B-cell depletion for SSc-PAH. Methods: In an NIH-sponsored, multicenter, double-blinded, randomized, placebo-controlled, proof-of-concept trial, 57 patients with SSc-PAH on stable-dose standard medical therapy received two infusions of 1,000 mg rituximab or placebo administered 2 weeks apart. The primary outcome measure was the change in 6-minute-walk distance (6MWD) at 24 weeks. Secondary endpoints included safety and invasive hemodynamics. We applied a machine learning approach to predict drug responsiveness. Measurements and Main Results: We randomized 57 subjects from 2010 to 2018. In the primary analysis, using data through Week 24, the adjusted mean change in 6MWD at 24 weeks favored the treatment arm but did not reach statistical significance (23.6 ± 11.1 m vs. 0.5 ± 9.7 m; P = 0.12). Although a negative study, when data through Week 48 were also considered, the estimated change in 6MWD at Week 24 was 25.5 ± 8.8 m for rituximab and 0.4 ± 7.4 m for placebo (P = 0.03). Rituximab treatment appeared to be safe and well tolerated. Low levels of RF (rheumatoid factor), IL-12, and IL-17 were sensitive and specific as favorable predictors of a rituximab response as measured by an improved 6MWD (receiver operating characteristic area under the curve, 0.88-0.95). Conclusions: B-cell depletion therapy is a potentially effective and safe adjuvant treatment for SSc-PAH. Future studies in these patients can confirm whether the identified biomarkers predict rituximab responsiveness. Clinical trial registered with www.clinicaltrails.gov (NCT01086540).

Sclerodermalike syndromes: Great imitators

Sclerodermalike syndromes (SLSs) comprise diseases with mucin deposition (eg, scleromyxedema, scleredema), with eosinophilia (eg, eosinophilic fasciitis), metabolic or biochemical abnormalities (eg, nephrogenic systemic fibrosis), or endocrine disorders (eg, POEMS syndrome, or polyneuropathy, organomegaly, endocrinopathy, monoclonal lymphoproliferative disorder, and hypothyroidism). Chronic graft-versus-host disease may also show sclerodermalike skin changes. Inherited progeria syndromes with early aging (eg, Werner syndrome) and a heterogeneous group of hereditary disorders with either skin thickening (eg, stiff skin syndrome) or atrophy and tightening (eg, acrogeria) can also imitate classic systemic sclerosis (SSc). In addition, SLSs can be provoked by several drugs, chemicals, or even physical injury (eg, trauma, vibration stress, radiation). In SLSs, the distribution of skin involvement seems to be atypical compared with SSc. The acral skin involvement is usually missing, and lack of Raynaud phenomenon, scleroderma-specific antinuclear antibodies, the absence of scleroderma capillary pattern, and internal organ manifestations indicate the presence of an SLS. Skin involvement is sometimes nodular, and the underlying tissues can also be affected. For the differential diagnosis, a skin biopsy of the deeper layers including fascia and muscle is required. Histology does not always allow differentiation between SSc and SLSs; therefore, the diagnosis is often based on the distribution, quality of cutaneous involvement, and other accompanying clinical features.

Prediction of therapeutic response before and during i.v. cyclophosphamide pulse therapy for interstitial lung disease in systemic sclerosis: A longitudinal observational study

There have been no established parameters to predict responsiveness to i.v. cyclophosphamide (IVCY) pulse therapy in combination with corticosteroids in patients with interstitial lung disease (ILD) related to systemic sclerosis (SSc). This retrospective study was conducted to determine predictive factors for efficacy of IVCY at the time of before and during the treatment. Thirty-two Japanese SSc patients, ever treated for ILD with IVCY in combination with prednisolone, were analyzed retrospectively. We performed detailed time-course analyses of parameters derived from blood samples and pulmonary function tests. With the exclusion of eight unclassified patients, 24 patients were classified into 14 good responders (GR) or 10 poor responders (PR) on the basis of changes in percent predicted diffusing capacity for carbon monoxide (DLco). Pretreatment percent predicted DLco was significantly reduced in PR compared with GR. In addition, serum parameters such as Krebs von den Lungen-6 (KL-6), surfactant protein D (SP-D) and C-reactive protein were significantly higher in PR than in GR. Furthermore, our time-course analyses revealed a transient increase in serum KL-6 levels with a peak at 3 months after the first infusion of cyclophosphamide, which showed no relation to therapeutic efficacy. Moreover, continuously high serum KL-6 levels (>2000 U/mL) and rapid decrease in SP-D levels (<200 ng/mL) during IVCY were remarkably characteristic of PR and GR, respectively. ILD severity/activity before treatment and variability of serum KL-6 and SP-D levels during treatment may be useful to predict therapeutic effects of IVCY on SSc-ILD.

Anti-nuclear autoantibodies in systemic sclerosis : News and perspectives

Systemic sclerosis is a connective tissue disorder characterized by microvascular damage and excessive fibrosis of the skin and internal organs. One hallmark of the immunological abnormalities in systemic sclerosis is the presence of anti-nuclear antibodies, which are detected in more than 90% of patients with systemic sclerosis. Anti-centromere antibodies, anti-DNA topoisomerase I antibodies, and anti-RNA polymerase III antibodies are the predominant anti-nuclear antibodies found in systemic sclerosis patients. Other systemic sclerosis-related anti-nuclear antibodies include those targeted against U3 ribonucleoprotein, Th/To, U11/U12 ribonucleoprotein, and eukaryotic initiation factor 2B. Anti-U1 ribonucleoprotein, anti-Ku antibodies, anti-PM-Scl, and anti-RuvBL1/2 antibodies are associated with systemic sclerosis overlap syndrome. Anti-human upstream binding factor, anti-Ro52/TRIM21, anti-B23, and anti-centriole antibodies do not have specificity to systemic sclerosis, but are sometimes detected in sera from patients with systemic sclerosis. Identification of each systemic sclerosis-related antibody is useful to diagnose and predict organ involvement, since the particular type of systemic sclerosis-related antibodies is often predictive of clinical features, severity, and prognosis. The clinical phenotypes are largely influenced by ethnicity. Currently, an immunoprecipitation assay is necessary to detect most systemic sclerosis-related antibodies; therefore, the establishment of an easy, reliable, and simple screening system is warranted.

Risk Factors for Future Scleroderma Renal Crisis at Systemic Sclerosis Diagnosis

OBJECTIVE

Systemic sclerosis (SSc) is a disease of autoimmunity, fibrosis, and vasculopathy. Scleroderma renal crisis (SRC) is one of the most severe complications. Corticosteroid exposure, presence of anti-RNA polymerase III antibodies (ARA), skin thickness, and significant tendon friction rubs are among the known risk factors at SSc diagnosis for developing future SRC. Identification of additional clinical characteristics and laboratory findings could expand and improve the risk profile for future SRC at SSc diagnosis.

METHODS

In this retrospective cohort study of the entire military electronic medical record between 2005 and 2016, we compared the demographics, clinical characteristics, and laboratory results at SSc diagnosis for 31 cases who developed SRC after SSc diagnosis to 322 SSc without SRC disease controls.

RESULTS

After adjustment for potential confounding variables, at SSc diagnosis these conditions were all associated with future SRC: proteinuria (p < 0.001; OR 183, 95% CI 19.1-1750), anemia (p = 0.001; OR 9.9, 95% CI 2.7-36.2), hypertension (p < 0.001; OR 13.1, 95% CI 4.7-36.6), chronic kidney disease (p = 0.008; OR 20.7, 95% CI 2.2-190.7), elevated erythrocyte sedimentation rate (p < 0.001; OR 14.3, 95% CI 4.8-43.0), thrombocytopenia (p = 0.03; OR 7.0, 95% CI 1.2-42.7), hypothyroidism (p = 0.01; OR 2.8, 95% CI 1.2-6.7), Anti-Ro antibody seropositivity (p = 0.003; OR 3.9, 95% CI 1.6-9.8), and ARA (p = 0.02; OR 4.1, 95% CI 1.2-13.8). Three or more of these risk factors present at SSc diagnosis was sensitive (77%) and highly specific (97%) for future SRC. No SSc without SRC disease controls had ≥ 4 risk factors.

CONCLUSION

In this SSc cohort, we present a panel of risk factors for future SRC. These patients may benefit from close observation of blood pressure, proteinuria, and estimated glomerular filtration rate, for earlier SRC identification and intervention. Future prospective therapeutic studies could focus specifically on this high-risk population.

Diagnostic criteria, severity classification and guidelines of systemic sclerosis

Several effective drugs have been identified for the treatment of systemic sclerosis (SSc). However, in advanced cases, not only their effectiveness is reduced but they may be also harmful due to their side-effects. Therefore, early diagnosis and early treatment is most important for the treatment of SSc. We established diagnostic criteria for SSc in 2003 and early diagnostic criteria for SSc in 2011, for the purpose of developing evaluation of each organ in SSc. Moreover, in November 2013, the American College of Rheumatology and the European Rheumatology Association jointly developed new diagnostic criteria for increasing their sensitivity and specificity, so we revised our diagnostic criteria and severity classification of SSc. Furthermore, we have revised the clinical guideline based on the newest evidence. In particular, the clinical guideline was established by clinical questions based on evidence-based medicine according to the New Minds Clinical Practice Guideline Creation Manual (version 1.0). We aimed to make the guideline easy to use and reliable based on the newest evidence, and to present guidance as specific as possible for various clinical problems in treatment of SSc.

Role of Autoantibodies in the Diagnosis of Connective-Tissue Disease ILD (CTD-ILD) and Interstitial Pneumonia with Autoimmune Features (IPAF)

The diagnosis of interstitial lung disease (ILD) requires meticulous evaluation for an underlying connective tissue disease (CTD), with major implications for prognosis and management. CTD associated ILD (CTD-ILD) occurs most commonly in the context of an established CTD, but can be the first and/or only manifestation of an occult CTD or occur in patients who have features suggestive of an autoimmune process, but not meeting diagnostic criteria for a defined CTD-recently defined as "interstitial pneumonia with autoimmune features" (IPAF). The detection of specific autoantibodies serves a critical role in the diagnosis of CTD-ILD, but there remains a lack of data to guide clinical practice including which autoantibodies should be tested on initial assessment and when or in whom serial testing should be performed. The implications of detecting autoantibodies in patients with IPAF on disease behaviour and management remain unknown. The evaluation of CTD-ILD is challenging due to the heterogeneity of presentations and types of CTD and ILD that may be encountered, and thus it is imperative that immunologic tests are interpreted in conjunction with a detailed rheumatologic history and examination and multidisciplinary collaboration between respiratory physicians, rheumatologists, immunologists, radiologists and pathologists.

The Clinical Relevance of Antifibrillarin (anti-U3-RNP) Autoantibodies in Systemic Sclerosis

Systemic sclerosis (SSc) is a heterogeneous autoimmune disease associated with several antinuclear autoantibodies useful to diagnosis and prognosis. The aim of the present multicentric study was to determine the clinical relevance of antifibrillarin autoantibodies (AFA) in patients with SSc. The clinical features of 37 patients with SSc positive for AFA (AFA+) and 139 SSc patients without AFA (AFA-) were collected retrospectively from medical records to enable a comparison between AFA- and AFA+ patients. Antifibrillarin autoantibodies were screened by an indirect immunofluorescence technique using HEp2 cells and identified by an in-house Western blot technique and/or an EliA test. Comparing AFA+ and AFA- patients, AFA+ patients were significantly younger at disease onset (36.9 versus 42.9; P = 0.02), more frequently male (P = 0.02) and of Afro-Caribbean descent (65% versus 7.7%; P < 0.001). At diagnosis, the Rodnan skin score evaluating the cutaneous manifestations was higher (13.3 versus 8.7; P = 0.01) and myositis was also more common in the AFA+ group (31.4% versus 12.2%; P < 0.01). Patients with AFA+ were not associated with diffuse cutaneous SSc or with lung involvement and no difference in survival was observed. Antifibrillarin autoantibodies are associated with patients of Afro-Caribbean origin and can identify patients with SSc who are younger at disease onset and display a higher prevalence of myositis.

Challenges and opportunities in treating inflammation associated with pulmonary hypertension

INTRODUCTION

Inflammatory cells are present in the lungs from patients with many, if not all, forms of severe pulmonary hypertension.

AREAS COVERED

Historically the first inflammatory cell identified in the pulmonary vascular lesions was the mast cell. T and B lymphocytes, as well as macrophages, are present in and around the pulmonary arterioles and many patients have elevated blood levels of interleukin 1 and 6; some patients show elevated levels of leukotriene B4. An overlap between collagen-vascular disease-associated pulmonary arterial hypertension (PAH) and idiopathic PAH exists, yet only a few studies have been designed that evaluate the effect of anti-inflammatory treatments. Here we review the pertinent data that connect PAH and inflammation/autoimmune dysregulation and evaluate experimental models of severe PAH with an emphasis on the Sugen/athymic rat model of severe PAH. Expert commentary: We postulate that there are several inflammatory phenotypes and predict that there will be several anti-inflammatory treatment strategies for severe PAH.

Scleroderma pathogenesis: a pivotal role for fibroblasts as effector cells

Scleroderma (systemic sclerosis; SSc) is characterised by fibrosis of the skin and internal organs in the context of autoimmunity and vascular perturbation. Overproduction of extracellular matrix components and loss of specialised epithelial structures are analogous to the process of scar formation after tissue injury. Fibroblasts are the resident cells of connective tissue that become activated at sites of damage and are likely to be important effector cells in SSc. Differentiation into myofibroblasts is a hallmark process, although the mechanisms and cellular origins of this important fibroblastic cell are still unclear. This article reviews fibroblast biology in the context of SSc and highlights the potentially important place of fibroblast effector cells in fibrosis. Moreover, the heterogeneity of fibroblast properties, multiplicity of regulatory pathways and diversity of origin for myofibroblasts may underpin clinical diversity in SSc, and provide novel avenues for targeted therapy.

Fibrosis--a lethal component of systemic sclerosis

Fibrosis is a pathological process characterized by excessive accumulation of connective tissue components in an organ or tissue. Fibrosis is produced by deregulated wound healing in response to chronic tissue injury or chronic inflammation, the hallmarks of rheumatic diseases. Progressive fibrosis, which distorts tissue architecture and results in progressive loss of organ function, is now recognized to be one of the major causes of morbidity and mortality in individuals with one of the most lethal rheumatic disease, systemic sclerosis (SSc). In this Review, we discuss the pathological role of fibrosis in SSc. We discuss the involvement of endothelium and pericyte activation, aberrant immune responses, endoplasmic reticulum stress and chronic tissue injury in the initiation of fibrosis in SSc. We then discuss fibroblast activation and myofibroblast differentiation that occurs in response to these initiating processes and is responsible for excessive accumulation of extracellular matrix. Finally, we discuss the chemical and mechanical signals that drive fibroblast activation and myofibroblast differentiation, which could serve as targets for new therapies for fibrosis in SSc.

Disease progression in systemic sclerosis-overlap syndrome is significantly different from limited and diffuse cutaneous systemic sclerosis

BACKGROUND

Systemic sclerosis (SSc)-overlap syndromes are a very heterogeneous and remarkable subgroup of SSc-patients, who present at least two connective tissue diseases (CTD) at the same time, usually with a specific autoantibody status.

OBJECTIVES

To determine whether patients, classified as overlap syndromes, show a disease course different from patients with limited SSc (lcSSc) or diffuse cutaneous SSc (dcSSc).

METHODS

The data of 3240 prospectively included patients, registered in the database of the German Network for Systemic Scleroderma and followed between 2003 and 2013, were analysed.

RESULTS

Among 3240 registered patients, 10% were diagnosed as SSc-overlap syndrome. Of these, 82.5% were female. SSc-overlap patients had a mean age of 48±1.2 years and carried significantly more often 'other antibodies' (68.0%; p<0.0001), including anti-U1RNP, -PmScl, -Ro, -La, as well as anti-Jo-1 and -Ku antibodies. These patients developed musculoskeletal involvement earlier and more frequently (62.5%) than patients diagnosed as lcSSc (32.2%) or dcSSc (43.3%) (p<0.0001). The onset of lung fibrosis and heart involvement in SSc-overlap patients was significantly earlier than in patients with lcSSc and occurred later than in patients with dcSSc. Oesophagus, kidney and PH progression was similar to lcSSc patients, whereas dcSSc patients had a significantly earlier onset.

CONCLUSIONS

These data support the concept that SSc-overlap syndromes should be regarded as a separate SSc subset, distinct from lcSSc and dcSSc, due to a different progression of the disease, different proportional distribution of specific autoantibodies, and of different organ involvement.

Frequency of disease-associated and other nuclear autoantibodies in patients of the German Network for Systemic Scleroderma: correlation with characteristic clinical features

Introduction

In the present study, we analysed in detail nuclear autoantibodies and their associations in systemic sclerosis (SSc) patients included in the German Network for Systemic Scleroderma Registry.

Methods

Sera of 863 patients were analysed according to a standardised protocol including immunofluorescence, immunoprecipitation, line immunoassay and immunodiffusion.

Results

Antinuclear antibodies (ANA) were detected in 94.2% of patients. In 81.6%, at least one of the autoantibodies highly associated with SSc or with overlap syndromes with scleroderma features was detected, that is, anti-centromere (35.9%) or anti-topoisomerase I (30.1%), followed in markedly lower frequency by antibodies to PM-Scl (4.9%), U1-ribonucleoprotein (U1-RNP) (4.8%), RNA polymerases (RNAPs) (3.8%), fibrillarin (1.4%), Ku (1.2%), aminoacyl-transfer RNA synthetases (0.5%), To (0.2%) and U11-RNP (0.1%). We found that the simultaneous presence of SSc-associated autoantibodies was rare (1.6%). Furthermore, additional autoantibodies were detected in 55.4% of the patients with SSc, of which anti-Ro/anti-La, anti-mitochondrial and anti-p25/p23 antibodies were most frequent. The coexistence of SSc-associated and other autoantibodies was common (43% of patients). SSc-associated autoantibodies disclosed characteristic associations with clinical features of patients, some of which were previously not acknowledged.

Conclusions

This study shows that five autoantigens (that is, centromere, topoisomerase I, PM-Scl, U1-RNP and RNAP) detected more than 95% of the known SSc-associated antibody responses in ANA-positive SSc patients and characterise around 79% of all SSc patients in a central European cohort. These data confirm and extend previous data underlining the central role of the determination of ANAs in defining the diagnosis, subset allocation and prognosis of SSc patients.

Coagulation and autoimmunity in scleroderma interstitial lung disease

OBJECTIVES

Interstitial lung disease in systemic sclerosis (SSc-ILD) is often an irreversible and progressive fibrosing process that now is the leading cause of scleroderma-related deaths. In this review we present our current understanding of the role played by coagulation and particularly by thrombin in autoimmune-mediated tissue injury and fibrosis, mainly as it relates to SSc-ILD.

METHODS

We used PubMed to search for articles published up to October 2010 for keywords referring to autoimmunity, coagulation, pulmonary fibrosis, and scleroderma.

RESULTS

SSc-ILD is an autoimmune disease associated with lymphocyte activation and release of various cytokines and growth factors. The production of autoantibodies is a central feature in SSc. Activation of the coagulation cascade with release of thrombin is 1 of the earliest events following tissue injury. Thrombin contributes to autoimmune responses by activating of pathogenic Th2 lymphocyte profile in SSc. Thrombin also modulates tissue repair responses, stimulates transformation of epithelial cells, endothelial cells, and fibroblasts into myofibroblast phenotype, and induces secretion of several pro-immune and profibrotic factors, which serve as antigens for pathogenic autoantibodies production in SSc-ILD.

CONCLUSIONS

The identification of links between autoimmunity and coagulation would provide new insights into the pathogenesis of pulmonary fibrosis associated with autoimmune diseases and further acknowledge the importance of thrombin in the development of SSc-ILD.

Increased production of a proliferation-inducing ligand (APRIL) by peripheral blood mononuclear cells is associated with antitopoisomerase I antibody and more severe disease in systemic sclerosis

OBJECTIVE

A proliferation-inducing ligand (APRIL), a member of the tumor necrosis factor (TNF) family, plays a crucial role in the survival of peripheral B cells, and may contribute to the pathogenesis of systemic sclerosis (SSc) through upregulation of autoantibody production and maintenance of autoimmune phenomena. We evaluated the capacity of peripheral blood mononuclear cells from patients with SSc (SSc-PBMC) to produce APRIL; and investigated correlations between production of APRIL by SSc-PBMC and clinical and laboratory features of the disease.

METHODS

PBMC from 20 patients with SSc and 14 healthy subjects were incubated in fetal calf serum-supplemented RPMI medium. APRIL levels were determined in cell culture supernatants by ELISA.

RESULTS

PBMC from patients with SSc produced significantly more APRIL (961 ± 151 pg/ml/10⁵ cells) than control PBMC (798 ± 219 pg/ml/10⁵ cells; p < 0.01). In patients with SSc, increased production of APRIL was associated with the presence of diffuse skin involvement, scleroderma lung disease, peripheral vasculopathy, greater capillary damage on capillaroscopy, and presence of anti-topoisomerase I (anti-topo I) antibodies. Multivariate regression analysis revealed anti-topo I antibodies as the only independent predictor of high production of APRIL by PBMC.

CONCLUSION

Production of APRIL is increased in SSc-PBMC and is associated with the presence of anti-topo I antibodies and more severe disease. Targeting the APRIL pathway might represent a therapeutic possibility for treatment of patients with SSc, in particular those with anti-topo I antibodies.

Serum endoglin levels in patients suffering from systemic sclerosis and elevated systolic pulmonary arterial pressure

Background. Pulmonary arterial hypertension (PAH) is the main cause of morbimortality in systemic sclerosis (SSc). Increased Eng expression has been demonstrated in SSc patients. Objective. Ascertaining serum levels of Eng in SSc patients with and without elevated systolic pulmonary arterial pressure (sPAP) and comparing them with that of healthy volunteers. Methods. A cross-sectional study was carried out. A commercial ELISA kit was used for measuring serum concentrations of Eng in 60 subjects: 40 patients with SSc with and without elevated sPAP, compared to 20 healthy control subjects. Elevated sPAP was detected by echocardiogram. Results. No association between positive Eng and elevated sPAP was found when compared to the SSc without elevated sPAP group (OR = 2.85; 0.65–12.88 95% CI; P = .11); however, an association was found between positive Eng and elevated sPAP compared to healthy controls (OR = 23.22; 2.46–1050.33 95% CI; P = .001), and weak association was found between the positive Eng with SSc without elevated sPAP group compared to healthy controls (OR = 8.14, 0.8–393.74 95% CI; P = .046). Conclusion. Raised serum levels of Eng in SSc patients compared to healthy controls were found, suggesting a role for Eng in SSc vasculopathy and not just in elevated sPAP. However, prospective studies are needed to verify such observations.

Regulatory T cells in the skin lesions and blood of patients with systemic sclerosis and morphoea

BACKGROUND

Systemic sclerosis (SSc) and morphoea are connective tissue diseases characterized by fibrosis of the skin. Although to date their pathogenesis has not been clearly defined, it is thought that autoimmunity may play a role in the development of the skin lesions observed in both these diseases. As regulatory T cells (Tregs) play a key role in the modulation of immune responses, it has recently been suggested that Treg impairment may lead to the development of autoimmune diseases.

OBJECTIVES

To investigate the presence of Tregs and their immunomodulatory cytokines, transforming growth factor (TGF)-beta and interleukin (IL)-10, in patients with SSc and morphoea.

PATIENTS/METHODS

Fifteen patients with SSc and 15 with morphoea were enrolled. Immunohistochemistry was applied to identify FoxP3+ (forkhead/winged helix transcription factor) Tregs, TGF-beta+ cells and IL-10+ cells in the skin, cytofluorometry to detect CD4+CD25+FoxP3+ Tregs in the blood, and enzyme-linked immunosorbent assays to analyse TGF-beta and IL-10 serum levels.

RESULTS

Fewer FoxP3+ Tregs and TGF-beta+ and IL-10+ cells were found in the skin of patients with scleroderma than in controls. Similarly, there were reduced TGF-beta and IL-10 serum levels and fewer circulating CD4+CD25brightFoxP3+ cells in patients with SSc or morphoea, than in controls.

CONCLUSIONS

The quantitative reduction of Tregs, together with that of TGF-beta and IL-10 serum levels, may be responsible for the loss of tolerance observed in both SSc and morphoea.

BANK1 functional variants are associated with susceptibility to diffuse systemic sclerosis in Caucasians

OBJECTIVE

To investigate the possible association of the BANK1 gene with genetic susceptibility to systemic sclerosis (SSc) and its subphenotypes.

METHODS

A large multicentre case-control association study including 2380 patients with SSc and 3270 healthy controls from six independent case-control sets of Caucasian ancestry (American, Spanish, Dutch, German, Swedish and Italian) was conducted. Three putative functional BANK1 polymorphisms (rs17266594 T/C, rs10516487 G/A, rs3733197 G/A) were selected as genetic markers and genotyped by Taqman 5 allelic discrimination assay.

RESULTS

A significant association of the rs10516487 G and rs17266594 T alleles with SSc susceptibility was observed (pooled OR=1.12, 95% CI 1.03 to 1.22; p=0.01 and pooled OR=1.14, 95% CI 1.05 to 1.25; p=0.003, respectively), whereas the rs3733197 genetic variant showed no statistically significant deviation. Stratification for cutaneous SSc phenotype showed that the BANK1 rs10516487 G, rs17266594 T and rs3733197 G alleles were strongly associated with susceptibility to diffuse SSc (dcSSc) (pooled OR=1.20, 95% CI 1.05 to 1.37, p=0.005; pooled OR=1.23, 95% CI 1.08 to 1.41, p=0.001; pooled OR=1.15, 95% CI 1.02 to 1.31, p=0.02, respectively). Similarly, stratification for specific SSc autoantibodies showed that the association of BANK1 rs10516487, rs17266594 and rs3733197 polymorphisms was restricted to the subgroup of patients carrying anti-topoisomerase I antibodies (pooled OR=1.20, 95% CI 1.02 to 1.41, p=0.03; pooled OR=1.24, 95% CI 1.05 to 1.46, p=0.01; pooled OR=1.26, 95% CI 1.07 to 1.47, p=0.004, respectively).

CONCLUSION

The results suggest that the BANK1 gene confers susceptibility to SSc in general, and specifically to the dcSSc and anti-topoisomerase I antibody subsets.

Skin disease: a cardinal feature of systemic sclerosis

Despite the heterogeneity of SSc, almost all patients have skin involvement. As such, skin manifestations are critical in the initial diagnosis of SSc and in the subsequent sub-classification into the different subsets of disease. The two principal subsets are lcSSc and dcSSc. The main difference between these two subsets is the speed of disease progression and the extent and severity of skin and visceral involvement; lcSSc has an insidious onset with skin involvement confined largely to the face and extremities. Whilst vascular manifestations of SSc such as pulmonary arterial hypertension are typically more common in lcSSc, patients in both subsets can develop ischaemic digital ulcers. In dcSSc, disease progression is very rapid, with skin thickening extending beyond the extremities and earlier, more widespread internal organ involvement. DcSSc is generally considered to be the more severe subset of the disease. Skin scores in SSc correlate inversely with survival and are considered a valuable marker of disease severity. Skin involvement is easily detectable and, using the modified Rodnan skin score, the degree of skin fibrosis can be quantified. As well as general management measures, a number of targeted therapies are commonly used for treatment of cutaneous manifestations of SSc. These include the intravenous prostanoid iloprost and the dual endothelin receptor antagonist bosentan, which is approved in Europe for the prevention of new digital ulcers.

Localized scleroderma and systemic sclerosis: is there a connection?

Excess fibrosis of the skin is a clinical hallmark of both localized scleroderma and systemic sclerosis. Localized scleroderma is generally thought to be a skin-limited disease whereas systemic sclerosis can have a wide range of internal organ involvement. Recent data suggest that a subset of patients with juvenile localized scleroderma can go on to develop systemic involvement of their disease. This raises the question of what the connection is, if any, between localized scleroderma and systemic sclerosis.

The immunobiology of systemic sclerosis

OBJECTIVES

Systemic sclerosis (SSc) is a chronic connective tissue disease characterized by vascular damage, autoimmunity, and excessive collagen deposition. Despite advances in disease-specific treatment of other rheumatologic diseases, disease-targeted treatment in SSc continues to be elusive. In this review, our goal was to place the contemporary immunobiology of SSc in the perspective of clinical medicine.

METHODS

We performed a PubMed search for the period from 1989 to 2007, using the keyword, "systemic sclerosis," resulting in a total of 9099 publications, including 1252 reviews. Articles were then selected based on their discussion of recent advances in the elusive pathogenesis of SSc. A final total of 259 articles were chosen for the review.

RESULTS

The SSc hallmarks of vascular damage, immunologic activation, and collagen deposition can be traced to 4 major factors: T-cells, fibroblasts, B-cells, and cytokines/chemokines. T-cells are a major component of the infiltrate in skin and lung, exhibiting increased expression of activation markers and showing signs of antigen-driven expansion. Preliminary data indicate that induction of oral tolerance with collagen, a target of SSc T-cell responses, is associated with clinical benefits. Although this suggests that T-cells participate in the pathogenesis of SSc, their precise role and antigen specificity largely remain to be elucidated. Defective numbers and functions of certain T-cell subsets, such as natural killer and gammadelta T-cells, may be involved in the failure to maintain tolerance. Other data suggest that gammadelta T-cells may themselves be effector cells in endothelial cell cytotoxicity. There are several lines of evidence for a pathogenic role of B-cells in SSc, in particular, through the production of autoantibodies. Antibody-dependent cell-mediated cytotoxicity is a primary pathogenic event in an animal model of SSc and is likely to be involved in human SSc. Nonetheless, there is as yet no convincing evidence for the pathogenicity of SSc-specific antibodies. SSc fibroblasts exhibit a specific phenotype characterized not only by excessive collagen production but also by increased responsiveness to and production of cytokines and chemokines. This phenotype is induced by a complex network of cytokines and chemokines but appears to be maintained in the absence of exogenous stimuli via the autocrine production of some of these factors by SSc fibroblasts themselves, particularly transforming growth factor, platelet-derived growth factor, monocyte chemoattractant protein 1, and interleukin-1.

CONCLUSIONS

Significant variations in laboratory data among patients suggest that the pathology reflects a heterogeneous disease. Nonetheless, the possibility of achieving clinical benefits by inducing oral tolerance highlights the importance of characterizing SSc T-cell antigens. It is hoped that the identification of some of the key players in the induction and maintenance of the SSc fibroblast phenotype may yield new disease-targeted treatment regimens for patients with SSc.

Rituximab: applications in dermatology

Rituximab is a chimeric anti-CD20 monoclonal antibody which has been used extensively for B-lymphocytic malignancies. In addition, applications for autoimmune diseases have emerged in recent years. Case reports support the use of rituximab in certain dermatologic conditions, including paraneoplastic pemphigus, pemphigus vulgaris, graft versus host disease, and cutaneous B-cell malignancies. Clinical trials are lacking and would be an appropriate next step.

The development of systemic sclerosis classification criteria

Systemic sclerosis (SSc) is a rare connective tissue disorder whose aetiology remains obscure, although environmental and genetic influences are likely to play a role. Disease registries have contributed to enhancing our understanding of this debilitating illness, but without sensitive, specific, and extensively validated classification criteria, accurate comparison between registries and the identification of patients suitable for clinical trials can be problematic. The American College of Rheumatology (ACR) criteria, published in 1980, have become outdated as our understanding of disease specific autoantibodies and nailfold capillaroscopy has improved. In addition, the sensitivity of the ACR criteria is low with respect to limited SSc. Although subsequent classification systems have been proposed, none has gained universal approval. The two- versus three-subset disease model remains a point of debate. Newly derived criteria are likely to draw upon the older classification systems as well as incorporating up-to-date diagnostic techniques and biomarkers. Validation will be critical before their use becomes widespread.

Is scleroderma an autoantibody mediated disease?

PURPOSE OF REVIEW

Research into the pathogenesis of systemic sclerosis and other fibrotic conditions is becoming increasingly broad and sophisticated. In the past year, several provocative studies have presented evidence that autoantibodies may actually cause the vascular damage and fibrosis characteristic of systemic sclerosis. These autoantibodies include antiendothelial cell, antifibrillin-1, anti-matrix metalloproteinases 1 and 3, and antiplatelelet-derived growth factor beta, each having its own unique mechanism. Such reports provide novel avenues to pursue in understanding this enigmatic disease.

Sklerodermie-assoziierte Autoantikörper – klinische und diagnostische Relevanz

In systemic sclerosis (SSc) and its variants, autoantibodies are the best known immunological aberration. In more than 95% of the patients, antinuclear antibodies or other autoantibodies can be detected. In about 90% of SSc patients with antinuclear antibodies, scleroderma associated autoantibodies highly specific for systemic sclerosis are found. These autoantibodies usually exclude each other in individual patients, and they are detectable early, persisting during the course of the disease. SSc patients characterized by scleroderma associated autoantibodies belong to disease subsets which are relatively homogeneous in clinical, genetic and prognostic terms. Besides these diagnostically relevant autoantibodies, numerous additional ones have also been described. These are neither SSc specific nor mutually exclusive, and their antigens have only been partially characterized. Some, however, are thought to be relevant to the as yet unanswered question of whether autoantibodies are directly involved in SSc pathogenesis.

The bleomycin-induced scleroderma model: what have we learned for scleroderma pathogenesis?

Scleroderma is a fibrotic condition characterized by immunologic abnormalities, vascular injury and increased accumulation of extracellular matrix (ECM) proteins in the skin. Although the etiology of scleroderma has not yet been fully elucidated, a growing body of evidence suggests that ECM overproduction by activated fibroblasts results from complex interactions among endothelial cells, lymphocytes, macrophages and fibroblasts, via a number of mediators, such as cytokines, chemokines and growth factors. For a better understanding of the pathophysiology of scleroderma, animal models are important tools. We established a murine model of cutaneous sclerosis by local treatment of bleomycin. This model reproduces several histological as well as biochemical aspects of human scleroderma. However, it must be emphasized that studying animal models cannot answer all the problems of human scleroderma. In this review, we introduce current insights into the pathogenesis of bleomycin-induced scleroderma, and discuss its contribution to our understanding of the pathogenesis of, and treatments for, human scleroderma.