Occupational and environmental scleroderma. Systematic review and meta-analysis

Occupational silica exposure in an Australian systemic sclerosis cohort

Objective

To determine the frequency of self-reported occupational exposure to silica in SSc patients enrolled in the Australian Scleroderma Cohort Study, and to compare the disease characteristics of the silica-exposed patients with those of the non-exposed patients.

Method

Data collected over a 12-year period from 1670 SSc patients were analysed. We compared the demographic and clinical characteristics of those who reported occupational silica exposure with those who did not. A subgroup analysis of male patients was performed, as well as a multivariable analysis of correlates of silica exposure.

Results

Overall, 126 (7.5%) of the cohort reported occupational silica exposure. These individuals were more likely to be male (73 of 231, i.e. 31.6% males exposed) and to have worked in mining and construction industries. Those who reported silica exposure were younger at the onset of SSc skin involvement [odds ratio (OR) 0.9, P = 0.02], of male gender (OR 14.9, P < 0.001), have joint contractures (OR 1.8, P = 0.05) and have higher physical disability as defined by scleroderma HAQ (OR 1.4, P = 0.01).

Conclusion

The highest percentage of silica exposure was found in males. These patients were more likely to have the presence of certain clinical manifestations and Scl-70 antibody, which is known to confer a poor prognosis. These findings support the association between occupational silica exposure and the subsequent development of SSc. Further investigation is required to describe the range of clinical manifestations and disease course, including prognosis and treatment response, in those diagnosed with occupationally induced SSc compared with idiopathic SSc.

Systemic sclerosis in an anaesthetist

Introduction

Systemic sclerosis is a potentially devastating disease in which the aetiology and pathogenesis has not yet been fully understood. It has been associated with occupational exposure to silica, vinyl chloride, solvents and other chemical agents.

Case summary

In this paper, we present the case of an anaesthetist who developed scleroderma after an occupational exposure to volatile anaesthetic gases (halothane, sevoflurane, isoflurane and enflurane) in operating theatres with poor scavenging systems and we discuss the possible causal link between occupational exposure and the disease.

Conclusions

The case reported is the second that we are aware of in recent years. Reporting scleroderma cases in workers may be the first step in assessing the causal link between occupational exposure to anaesthetic gases and the disease.

Is exposure to environmental factors associated with a characteristic clinical and laboratory profile in systemic sclerosis? A retrospective analysis

To identify environmental factors (EF) in a large cohort of patients with systemic sclerosis (SSc) analyzing their clinical and laboratory presentation. A cohort of consecutive patients attended at a single Brazilian SSc outpatient clinic was analyzed regarding EF. Data were analyzed according to clinical, demographic and laboratory characteristics, as well as SSc subtype. In a cohort of 662 patients, 70 (10.6%) had known previous exposure to EF, predominantly organic solvents (51.4%), silica (20%), silicone (12.9%) and pesticides (11.4%). In the SSc cohort, patients with EF had a significantly higher frequency of male gender (p < 0.01), African-Brazilian ethnicity (p = 0.01), myopathy (p = 0.02), and pigmentary disorders (p = 0.04), with shorter disease duration (p = 0.01). When SSc subtypes were analyzed separately, there was positive association with male gender in limited (p < 0.01) and diffuse (p < 0.01) SSc, as well as African-Brazilian ethnicity (p = 0.04), severe interstitial lung disease (p < 0.01), myopathy (p = 0.02) and SD pattern at nailfold capillaroscopy (p = 0.01) in limited SSc, and negative association with esophageal hypomotility (p < 0.01) and ANA positivity (p = 0.02) in diffuse SSc. Multiple regression analyses showed that myopathy was independently associated with previous exposure to EF (OR = 2.09; 95% CI 1.15-3.82), especially silica exposure (OR = 3.09; 95% CI 1.67-5.73). This study showed that SSc patients with previous exposure to EF may have some specific clinical characteristics, mainly a higher frequency of myopathy, also showing more severe ILD, preferably in male and African-Brazilian patients, associated with a lower frequency of ANA positivity.

Mechanisms of Environment-Induced Autoimmunity

Although numerous environmental exposures have been suggested as triggers for preclinical autoimmunity, only a few have been confidently linked to autoimmune diseases. For disease-associated exposures, the lung is a common site where chronic exposure results in cellular toxicity, tissue damage, inflammation, and fibrosis. These features are exacerbated by exposures to particulate material, which hampers clearance and degradation, thus facilitating persistent inflammation. Coincident with exposure and resulting pathological processes is the posttranslational modification of self-antigens, which, in concert with the formation of tertiary lymphoid structures containing abundant B cells, is thought to promote the generation of autoantibodies that in some instances demonstrate major histocompatibility complex restriction. Under appropriate gene-environment interactions, these responses can have diagnostic specificity. Greater insight into the molecular and cellular requirements governing this process, especially those that distinguish preclinical autoimmunity from clinical autoimmunedisease, may facilitate determination of the significance of environmental exposures in human autoimmune disease.

Low dose intravenous immunoglobulin in addition to cyclophosphamide in systemic sclerosis : Single centre experience

AIM

Systemic sclerosis (SSc) is a rare chronic disease characterized by pathologic collagen deposits in the skin and internal organs. Although it is considered to be an autoimmune disease, immunosuppressants have a limited effect on severe SSc. Intravenous immunoglobulins (IVIG) have shown favorable effects in patients with SSc by suppressing the action of profibrotic cytokines, so they could have additional effect on standard treatment such as cyclophosphamide (CYC). This article presents the immunomodulatory effect of low-dose IVIG in addition to CYC in the treatment of severe SSc in this center during the last 9 years.

METHODS

This retrospective observational study analyzed the medical documentation of nine patients with SSc treated with low-dose IVIG (0.4 g/kg and month) together with intravenous CYC (600 mg/m² and month). The therapeutic effect on lung and skin manifestations was assessed.

RESULTS

Of the patients one had interstitial lung diseases (ILD), two had progressive skin diseases, and six had a combination of skin and lung involvement. The best results were achieved in skin changes, where complete healing of digital ulcers (DU) was recorded in every reported case. A decrease in the modified Rodnan skin score (mRSS) was noted in three patients and increased diffusion capacity of the lungs for carbon monoxide in another three patients.

CONCLUSION

The results of the study suggest that IVIG may be an additional treatment option together with CYC for patients for whom other therapies have failed, but further studies on the exact role of IVIG in the treatment of severe SSc are required.

The association between hepatitis B, hepatitis C and systemic sclerosis: a cross-sectional study

PURPOSE OF REVIEW

To investigate the association between systemic sclerosis (SSc) to chronic hepatitis B virus (HBV) and hepatitis C virus (HCV) carriage. We utilized the database of Clalit Health Services, the largest healthcare organization in Israel and performed a cross-sectional study.

RECENT FINDINGS

The study included 2431 SSc patients and 12 710 age-and-sex matched controls, HBV was found in 38 SSc patients (1.56%) and 64 controls (0.5%). HCV was found in 30 SSc patients (1.23%) and 83 controls (0.65%). In multivariable logistic regression model, HBV was found to be associated with smoking, dialysis treatment and SSc [odds ratio (OR) 2.97, 95% confidence interval (CI) 1.92-4.53]. HCV was found to be associated with dialysis treatment and SSc (OR 1.73, 95% CI 1.1-2.66). A trend was found between both HBV and HCV toward low socioeconomic status. SSc patients with HBV had demonstrated higher rates of end-stage renal disease requiring dialysis treatment.

SUMMARY

In our study, HBV and HCV were found to be associated with SSc. Common immune mechanisms or therapeutic modalities may serve as mediators of this association.

Deregulation of long noncoding RNAs ANCR, TINCR, HOTTIP and SPRY4-IT1 in plasma of systemic sclerosis patients: SPRY4-IT1 as a novel biomarker of scleroderma and its subtypes

Systemic sclerosis or systemic scleroderma (SSc) is an inflammatory autoimmune disease whose pathogenesis remains ambiguous; however, epigenetics, including long noncoding RNAs (lncRNAs) is an emerging paradigm. To date, the expression, role and clinical significance of most lncRNAs in SSc remain unelucidated. Herein, we investigated the plasma expression profiles of lncRNAs; ANCR, TINCR, HOTTIP, and SPRY4-IT1, which were linked to skin biology, in SSc patients and its subtypes, their potential as diagnostic tools and their correlations with autoantibodies and disease manifestations. Sixty-three SSc patients and thirty-five healthy volunteers were recruited. Autoantibody profile (anti-Scl-70, anti-centromere, anti-RNA polymeraseIII, anti-ribonucleoprotein, antinuclear, and anti-phospholipid antibodies) was determined. lncRNAs analysis was conducted using RT-qPCR. Plasma TINCR, HOTTIP, and SPRY4-IT1 upregulation and ANCR downregulation were observed in SSc patients compared with controls. SPRY4-IT1 was superior in SSc diagnosis in ROC analysis and predicted its risk in multivariate logistic analysis. Plasma SPRT4-IT1 was higher in diffuse than limited SSc. SPRY4-IT1 and HOTTIP were positively correlated with modified Rodnan skin score while ANCR showed a negative correlation only in limited SSc. ANCR and TINCR were positively correlated with disease duration and ESR, respectively. ANCR and SPRY4-IT1 were positively correlated with pulmonary hypertension. HOTTIP was positively correlated with antinuclear antibody. SPRY4-IT1 was positively correlated with HOTTIP in the whole group, and with TINCR only in diffuse SSc. We introduce plasma SPRY4-IT1, HOTTIP, ANCR and TINCR as novel candidate biomarkers for SSc, with SPRY4-IT1 could predict SSc diagnosis and discriminate its subtypes. Our findings widen the epigenetic landscape of SSc and provide surrogates for future predictive studies.

Systemic sclerosis: Advances towards stratified medicine

Epidemiological studies reporting demographic, clinical and serological factors predictive of various outcomes in systemic sclerosis (SSc) range from the prediction of mortality to the development and progression of disease manifestations. However, predicting the disease trajectory in the individual patient is a challenging but important step towards a stratified approach to disease management. Recent technological advances provide the opportunity for new subgroupings of disease based on risk stratification, through the systematic analysis of high-dimensional clinical data combined with genes, their transcription products and their corresponding translated proteins. In addition, these variables offer a rich vein of research to identify non-invasive biomarkers for predicting organ involvement and to assess disease activity and response to therapy. Selection of patients with a clinical phenotype or molecular signature relevant to the therapy under study combined with recent efforts to standardise outcome measures, show promise for improving clinical trial design and the identification of effective targeted therapies.

Viral pneumonia and pulmonary alveolar proteinosis: the cause and the effect, case report

Pulmonary alveolar proteinosis (PAP) is a rare lung disease characterized by the accumulation of amorphous lipoproteinaceous material in the distal air spaces due to defective surfactant clearance by alveolar macrophages. This leads to impaired gas exchange and arterial hypoxemia of varying degrees. Although autoimmune type of PAP is thought to be idiopathic, this focused report highlights the possible relationship between viral pneumonia and autoimmune PAP (APAP) in terms of causation, superinfection and effect of treatments. We report a newly diagnosed case of APAP with a possible viral causation "trigger" for the confirmed serum anti-granulocyte macrophage-colony stimulating factor (GM-CSF) antibody. To the best of our knowledge, this is the first report that describe and discuss this issue. The patient is a 38-year-old, ex-smoker woman who had had a progressively worsening dyspnea and a persistent, productive cough for more than 4 months. It was thought to be a community acquired pneumonia (CAP) case and was treated with multiple antibiotics which yielded no improvement in her condition. Physical examination revealed mild hypoxemia and minimal bilateral fine crepitations despite marked alveolar filling on chest X-ray (CXR). She underwent a bronchoscopic procedure that revealed PAP. The case also describes an acute flare up of the condition during the course of the disease caused by a confirmed H1N1 influenza infection. APAP should be considered in the differential diagnosis of recurrent pneumonia not responding to treatment. In this case report we suggest the possible role of viral causation "trigger" or cross-reactivity of GM-CSF antibodies that lead to APAP. We also describe the provided management, the response to the antiviral therapy and the diagnostic and management challenges that was encountered during the follow up.

Epigenetics of scleroderma: Integrating genetic, ethnic, age, and environmental effects

Scleroderma or systemic sclerosis is thought to result from the interplay between environmental or non-genetic factors in a genetically susceptible individual. Epigenetic modifications are influenced by genetic variation and environmental exposures, and change with chronological age and between populations. Despite progress in identifying genetic, epigenetic, and environmental risk factors, the underlying mechanism of systemic sclerosis remains unclear. Since epigenetics provides the regulatory mechanism linking genetic and non-genetic factors to gene expression, understanding the role of epigenetic regulation in systemic sclerosis will elucidate how these factors interact to cause systemic sclerosis. Among the cell types under tight epigenetic control and susceptible to epigenetic dysregulation, immune cells are critically involved in early pathogenic events in the progression of fibrosis and systemic sclerosis. This review starts by summarizing the changes in DNA methylation, histone modification, and non-coding RNAs associated with systemic sclerosis. It then discusses the role of genetic, ethnic, age, and environmental effects on epigenetic regulation, with a focus on immune system dysregulation. Given the potential of epigenome editing technologies for cell reprogramming and as a therapeutic approach for durable gene regulation, this review concludes with a prospect on epigenetic editing. Although epigenomics in systemic sclerosis is in its infancy, future studies will help elucidate the regulatory mechanisms underpinning systemic sclerosis and inform the design of targeted epigenetic therapies to control its dysregulation.

Scleroderma-like syndrome in a woman with silicone breast implants - case report and critical review of the literature

Various silicon compounds have been reported to stimulate autoimmune reactions in the human body. Based on case reports, a possible causal association between silicone breast implants and systemic sclerosis has been suggested since the end of the 1970s. Although the relationship between systemic sclerosis and silicone breast implants has been intensely investigated, no clear evidence of such an association has ever been found in epidemiological studies. Instead, it is now proposed that silicone breast implants can induce nonspecific symptoms of inflammatory diseases, despite not fulfilling the diagnostic criteria for a specific autoimmune disease. This phenomenon was named autoimmune syndrome induced by adjuvants (ASIA syndrome). ASIA syndrome is worth considering in the differential diagnosis in rheumatology patients. In this paper, we present a case of the scleroderma-like syndrome in a 48-year-old woman with a broken silicone breast implant and a review the current literature on this issue.

Unraveling SSc Pathophysiology; The Myofibroblast

Systemic sclerosis (SSc) is a severe auto-immune disease, characterized by vasculopathy and fibrosis of connective tissues. SSc has a high morbidity and mortality and unfortunately no disease modifying therapy is currently available. A key cell in the pathophysiology of SSc is the myofibroblast. Myofibroblasts are fibroblasts with contractile properties that produce a large amount of pro-fibrotic extracellular matrix molecules such as collagen type I. In this narrative review we will discuss the presence, formation, and role of myofibroblasts in SSc, and how these processes are stimulated and mediated by cells of the (innate) immune system such as mast cells and T helper 2 lymphocytes. Furthermore, current novel therapeutic approaches to target myofibroblasts will be highlighted for future perspective.

Occupational Lung Diseases: Underreported Diagnosis in Radiological Practice

Underreporting of occupational lung diseases is a widespread problem in clinical practice. In Europe there is not a common regulation even for the recognition of occupational cancers. Furthermore epidemiologic data on occupational interstitial lung diseases, in general, is limited by no standardized diagnostic criteria, varied physician awareness and training, limitations inherent to the various data sources, and the long latency period. Therefore, to optimize the management of the patient with occupational pathology, the collaboration and skills of the multidisciplinary at the service of the patient, play a fundamental role. In particular, radiologists should give substance to a clinical suspicion on an anamnestic basis and at the same time should recognize patterns of illness that can lead to the emergence of stories of misunderstood exposures. This article aims to provide an overview of the main occupational lung diseases with attention to diagnostic possibilities of the different imaging techniques. The issue of the radiological error is investigated, providing tools to minimize it in the daily practice.

Subradiological silicosis

The purpose of this commentary is to bring the neglected phenomenon of subradiological silicosis and its implications to the attention of readers. We define subradiological silicosis as silicosis detectable on pathological examination of lung tissue but not visible radiologically. For extent of the phenomenon, we draw on a study using a large South African autopsy database of deceased miners and chest radiographs taken in life. At an International Labour Organization threshold of >1/0 only 43% of all pathologically detected cases were detected on chest radiograph, and only 62% of those classified on pathology as "moderate or marked" silicosis. Subradiological silicosis has a number of implications for research and practice: for dose-response studies of silicosis; for studies of the relationship between silica and conditions such as tuberculosis, lung cancer, and autoimmune disease, including the mechanistic role of fibrogenesis; for prognostication in silica exposed workers; and for workers' compensation criteria.

Bank1 and NF-kappaB as key regulators in anti-nucleolar antibody development

Systemic autoimmune rheumatic disorders (SARD) represent important causes of morbidity and mortality in humans. The mechanisms triggering autoimmune responses are complex and involve a network of genetic factors. Mercury-induced autoimmunity (HgIA) in mice is an established model to study the mechanisms of the development of antinuclear antibodies (ANA), which is a hallmark in the diagnosis of SARD. A.SW mice with HgIA show a significantly higher titer of antinucleolar antibodies (ANoA) than the B10.S mice, although both share the same MHC class II (H-2). We applied a genome-wide association study (GWAS) to their Hg-exposed F2 offspring to investigate the non-MHC genes involved in the development of ANoA. Quantitative trait locus (QTL) analysis showed a peak logarithm of odds ratio (LOD) score of 3.05 on chromosome 3. Microsatellites were used for haplotyping, and fine mapping was conducted with next generation sequencing. The candidate genes Bank1 (B-cell scaffold protein with ankyrin repeats 1) and Nfkb1 (nuclear factor kappa B subunit 1) were identified by additional QTL analysis. Expression of the Bank1 and Nfkb1 genes and their downstream target genes involved in the intracellular pathway (Tlr9, Il6, Tnf) was investigated in mercury-exposed A.SW and B10.S mice by real-time PCR. Bank1 showed significantly lower gene expression in the A.SW strain after Hg-exposure, whereas the B10.S strain showed no significant difference. Nfkb1, Tlr9, Il6 and Tnf had significantly higher gene expression in the A.SW strain after Hg-exposure, while the B10.S strain showed no difference. This study supports the roles of Bank1 (produced mainly in B-cells) and Nfkb1 (produced in most immune cells) as key regulators of ANoA development in HgIA.

Genetics of immune-mediated inflammatory diseases

Immune-mediated inflammatory diseases (IMIDs) are characterized by dysregulation of the normal immune response, which leads to inflammation. Together, they account for a high disease burden in the population, given that they are usually chronic conditions with associated co-morbidities. Examples include systemic lupus erythematosus, rheumatoid arthritis, Crohn's disease and type 1 diabetes. Since the advent of genome-wide association studies, evidence of considerable genetic overlap in the loci predisposing to a wide range of IMIDs has emerged. Understanding the genetic risk and extent of genetic overlap between IMIDs may help to determine which genes control which aspects of the different diseases; it may identify potential novel therapeutic targets for a number of these conditions, and/or it may facilitate repurposing existing therapies developed originally for different conditions. The findings show that autoantibody-mediated autoimmune diseases cluster more closely with each other than autoantibody-negative diseases such as psoriasis, psoriatic arthritis, Crohn's disease and ankylosing spondylitis which, instead, form a seronegative genetic cluster. The genetic clustering largely mirrors the known response to existing biological therapies, but apparent anomalies in treatment response are discussed.

Blue toe syndrome as a first sign of systemic sclerosis

We describe an unusual case of blue toe syndrome as the primary and solitary manifestation of systemic sclerosis. The possible cause was long-term occupational exposure in construction work. Blue toe syndrome is a small vessel disease, characterised by the sudden development of painful, blue discolouration in one or more toes. The most common aetiology is atheroembolic disease; however, it can also appear in several conditions ranging from hypercoagulability disorders to underlying systemic diseases such as vasculitis or autoimmune diseases. Here, we describe the case of a 57-year-old man who presented with blue toe syndrome without underlying atheroembolic disease. He was found to have positive anticentromere antibodies, which indicated that systemic sclerosis was the likely primary underlying cause. An extensive systemic evaluation and a thorough physical examination revealed no other symptoms associated with systemic sclerosis. He was prescribed nifedipin and rosuvastatin, and showed complete resolution of symptoms after 3 months.

Genome-Wide DNA Methylation Analysis in Systemic Sclerosis Reveals Hypomethylation of IFN-Associated Genes in CD4+ and CD8+ T Cells

Epigenetic modifications, including DNA methylation, play an important role in the pathogenesis of autoimmune diseases. In this study, we characterized the DNA methylome in primary T cells of patients with systemic sclerosis. Genome-wide DNA methylation assays of CD4⁺ and CD8⁺ T cells from 24 systemic sclerosis patients and 24 matched controls were conducted and differentially methylated regions were validated. In the discovery stage, we found that hypomethylation of genes involved in the type I IFN signaling pathway was significantly enriched in both CD4⁺ (P = 7.59 × 10^-6) and CD8⁺ (P = 2.10 × 10^-8) differentially methylated regions. In the validation stage, we confirmed these changes for five type I IFN-associated genes. In addition, protein levels of both type I IFN-α (P < 0.0001) and β (P = 0.002) were significantly elevated in the sera of systemic sclerosis patients. Moreover, significant associations between type I IFN-α/β protein levels with the DNA methylation status as well as the expression profiles of these IFN-associated genes were confirmed. In conclusion, the type I IFN pathway is dysfunctional at the epigenetic level in systemic sclerosis patients, indicating that hypomethylation and upregulation of type I IFN-associated genes might be critical in systemic sclerosis pathogenesis.