Multiple clinical and biological autoimmune manifestations in 50 workers after occupational exposure to silica

Analysis of Immune Cell Subsets in Peripheral Blood from Patients with Engineered Stone Silica-Induced Lung Inflammation

Silicosis caused by engineered stone (ES-silicosis) is an emerging worldwide issue characterized by inflammation and fibrosis in the lungs. To our knowledge, only a few reports have investigated leukocyte/lymphocyte subsets in ES-silicosis patients. The present study was designed to explore the proportions of the main lymphocyte subsets in ES-silicosis patients stratified into two groups, one with simple silicosis (SS) and the other with a more advanced state of the disease, defined as progressive massive fibrosis (PMF). The proportions of B (memory and plasmablasts) cells, T (helper, cytotoxic, regulatory) cells, and natural killer (NK) (regulatory and cytotoxic) cells were investigated by multiparameter flow cytometry in 91 ES-silicosis patients (53 SS patients and 38 PMF patients) and 22 healthy controls (HC). Although the total number of leukocytes did not differ between the groups studied, lymphopenia was observed in patients compared to healthy controls. Compared with those in healthy controls, the proportions of memory B cells, naïve helper T cells, and the CD4+/CD8+ T cells' ratio in the peripheral blood of patients with silicosis were significantly decreased, while the percentages of plasma cells, memory helper T cells, and regulatory T cells were significantly increased. For the NK cell subsets, no significant differences were found between the groups studied. These results revealed altered cellular immune processes in the peripheral blood of patients with ES-silicosis and provided further insight into silicosis pathogenesis.

Environmental pollutants and phosphoinositide signaling in autoimmunity

Environmental pollution stands as one of the most critical challenges affecting human health, with an estimated mortality rate linked to pollution-induced non-communicable diseases projected to range from 20% to 25%. These pollutants not only disrupt immune responses but can also trigger immunotoxicity. Phosphoinositide signaling, a pivotal regulator of immune responses, plays a central role in the development of autoimmune diseases and exhibits high sensitivity to environmental stressors. Among these stressors, environmental pollutants have become increasingly prevalent in our society, contributing to the initiation and exacerbation of autoimmune conditions. In this review, we summarize the intricate interplay between phosphoinositide signaling and autoimmune diseases within the context of environmental pollutants and contaminants. We provide an up-to-date overview of stress-induced phosphoinositide signaling, discuss 14 selected examples categorized into three groups of environmental pollutants and their connections to immune diseases, and shed light on the associated phosphoinositide signaling pathways. Through these discussions, this review advances our understanding of how phosphoinositide signaling influences the coordinated immune response to environmental stressors at a biological level. Furthermore, it offers valuable insights into potential research directions and therapeutic targets aimed at mitigating the impact of environmental pollutants on the pathogenesis of autoimmune diseases. SYNOPSIS: Phosphoinositide signaling at the intersection of environmental pollutants and autoimmunity provides novel insights for managing autoimmune diseases aggravated by pollutants.

Colinet-Caplan Syndrome: History of an Outbreak of Autoimmune Disease in Scouring Powder Workers

The first modern description linking rheumatoid arthritis to occupational dust exposure is generally attributed to the British physician Anthony Caplan. In 1953, Caplan reported on a "peculiar" nodular pattern on chest radiographs of Welsh coal miners with rheumatoid arthritis that differed from the typical coal workers' pneumoconiosis. However, as early as 1950, the Belgian rheumatologist Émile Colinet described a similar case of rheumatoid arthritis and concomitant pulmonary opacities in a 30-year-old woman with silica exposure. Soon after, he published a second case. Although this condition initially was called Colinet-Caplan syndrome in the Francophone biomedical literature, Colinet's name was later dropped from the eponym. Because Colinet never clearly described the specific occupational context of his cases, Caplan syndrome has been misconstrued as uniquely a disease of coal miners. We attempted to reconstruct the working conditions of Colinet's patients and found that they were packing Vim, a silica-based scouring powder, at the Savonneries Lever Frères factory in Brussels, Belgium. Colinet's cases were only the first 2 in a series of reports of rheumatoid arthritis and other autoimmune diseases, mainly among young women, in those who worked in the production of silica-based scouring powder between the 1930s and 1980s across Europe. The largest outbreak involved 32 cases of autoimmune disease among 50 former workers of a Spanish scouring powder manufacturing facility. After silica in scouring powders was replaced with less hazardous materials later in the 20th century, no further cases have been reported. Although scouring powder disease is a historical phenomenon, autoimmune disorders linked to occupational exposure to silica and coal dust have not disappeared but instead are reemerging among those who work with silica-based artificial stone and in other dusty trades.

Silica associated systemic sclerosis: an occupational health hazard

A middle-aged male working in the sandblasting and stone-cutting industry was brought to the medicine department with skin tightness, dysphagia and discolouration of the skin for the last 1 year. On examination, he had skin thickening over the face and the extremities with restricted mouth opening. His hands were cold and showed peripheral cyanosis. Systemic examination was suggestive of diffuse cutaneous systemic sclerosis, further confirmed by the antinuclear antibody testing. Further, CT of the chest showed mediastinal lymphadenopathy with eggshell calcification and interstitial fibrosis consistent with silicosis and fibrotic non-specific interstitial pneumonitis. The patient was started on pulse monthly cyclophosphamide for six cycles, and steroids were given for 4 weeks and tapered. Tadalafil and amlodipine were given for his pulmonary artery hypertension and Raynaud's phenomenon, respectively. This case also highlights the importance of periodic screening of the workers exposed to silica dust to prevent silicosis.

The EXIMIOUS project—Mapping exposure-induced immune effects: connecting the exposome and the immunome

Immune-mediated, noncommunicable diseases—such as autoimmune and inflammatory diseases—are chronic disorders, in which the interaction between environmental exposures and the immune system plays an important role. The prevalence and societal costs of these diseases are rising in the European Union. The EXIMIOUS consortium—gathering experts in immunology, toxicology, occupational health, clinical medicine, exposure science, epidemiology, bioinformatics, and sensor development—will study eleven European study populations, covering the entire lifespan, including prenatal life. Innovative ways of characterizing and quantifying the exposome will be combined with high-dimensional immunophenotyping and -profiling platforms to map the immune effects (immunome) induced by the exposome. We will use two main approaches that “meet in the middle”—one starting from the exposome, the other starting from health effects. Novel bioinformatics tools, based on systems immunology and machine learning, will be used to integrate and analyze these large datasets to identify immune fingerprints that reflect a person’s lifetime exposome or that are early predictors of disease. This will allow researchers, policymakers, and clinicians to grasp the impact of the exposome on the immune system at the level of individuals and populations.

Association of Silicosis and Dermatomyositis: Case Report and Literature Review

The association between silicosis and autoimmune diseases is not uncommon. Silicosis is well correlated with rheumatoid arthritis and systemic lupus erythematosus. However, cases of dermatomyositis associated with silicosis are relatively understudied. We report a case of a 59-year-old man with a history of cardiac, respiratory, and systemic symptoms for the duration of a year, who present to the ER with acute dyspnea, fever, chest pain, and dry cough, and was diagnosed with silicosis and dermatomyositis. In this case report, we discuss the workup done in order to reach the diagnosis, as well as the pathological mechanism that might have led to the emergence of those two entities in the same patient.

Mine-site derived particulate matter exposure exacerbates neurological and pulmonary inflammatory outcomes in an autoimmune mouse model

The Southwestern United States has a legacy of industrial mining due to the presence of rich mineral ore deposits. The relationship between environmental inhaled particulate matter (PM) exposures and neurological outcomes within an autoimmune context is understudied. The aim of this study was to compare two regionally-relevant dusts from high-priority abandoned mine-sites, Claim 28 PM, from Blue Gap Tachee, AZ and St. Anthony mine PM, from the Pueblo of Laguna, NM and to expose autoimmune-prone mice (NZBWF1/J). Mice were randomly assigned to one of three groups (n = 8/group): DM (dispersion media, control), Claim 28 PM, or St. Anthony PM, subjected to oropharyngeal aspiration of (100 µg/50 µl), once per week for a total of 4 consecutive doses. A battery of immunological and neurological endpoints was assessed at 24 weeks of age including: bronchoalveolar lavage cell counts, lung gene expression, brain immunohistochemistry, behavioral tasks and serum autoimmune biomarkers. Bronchoalveolar lavage results demonstrated a significant increase in number of polymorphonuclear neutrophils following Claim 28 and St. Anthony mine PM aspiration. Lung mRNA expression showed significant upregulation in CCL-2 and IL-1ß following St. Anthony mine PM aspiration. In addition, neuroinflammation was present in both Claim 28 and St. Anthony mine-site derived PM exposure groups. Behavioral tasks resulted in significant deficits as determined by Y-maze new arm frequency following Claim 28 aspiration. Neutrophil elastase was significantly upregulated in the St. Anthony mine exposure group. Interestingly, there were no significant changes in serum autoantigens suggesting systemic inflammatory effects may be mediated through other molecular mechanisms following low-dose PM exposures.

Silicosis: An Update and Guide for Clinicians

This overview provides an update on silicosis epidemiology with review of exposures and emerging trends in acute and accelerated silicosis in the twenty-first century. The silicosis epidemics in mining, denim sandblasting, and engineering stone industries are highlighted. Clinical presentations of silicosis and silica-related conditions such as autoimmune, kidney, and mycobacterial disease, as well as lung cancer, are discussed. Important aspects of the new OSHA 2017 Silica Standard are presented. This review also includes practical guidance for clinicians to address questions that may arise when evaluating silica-exposed patients and to the public health responses needed following a diagnosis of silica-related disease.

Rheumatological Diseases in Denim Sandblasters with Silicosis: What Should Pulmonologists Look for?

OBJECTIVE

Silica exposure is not only the cause of silicosis, also associated rheumatological diseases like rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), and systemic sclerosis (SSc). This report will reveal the rheumatological diseases of silicosis patients who were exposed to silica while working as denim sandblasters. Additionally, we will describe some clinical and laboratory findings that will help pulmonologist suspect, recognize and manage rheumatological diseases related to silica exposure in patients with silicosis.

MATERIAL AND METHODS

We reviewed the records of 142 sandblasters diagnosed with silicosis and found ten silicosis cases who also had rheumatological diseases between the years 2009 and 2017. The occupational characteristics, serological, functional and radiological data, were collected for patients of silicosis with rheumatological diseases.

RESULTS

Ten silicosis patients with concomitant rheumatological diseases were found. Six patients among our cases had diagnosed SSc (4.2%), three of them had RA (2.1%), and one of them was being monitored for SLE (0.7%). The mean silica exposure time of the cases was 4.3±1.9 years (min: 1 max: 8). We also found elevated LD, sedimentation and CRP levels in our cases.

CONCLUSION

It should be kept in mind that, in silicosis cases with arthralgia, joint tenderness or sclerosis at the fingertips may be indicative of rheumatological diseases related to silica exposure, and in these cases, the unexplained elevations of sedimentation and CRP levels may also be a result of silica-induced rheumatological diseases.

Classical Examples of the Concept of the ASIA Syndrome

Autoimmune/inflammatory syndrome induced by adjuvants (ASIA) was first introduced in 2011 by Shoenfeld et al. and encompasses a cluster of related immune mediated diseases, which develop among genetically prone individuals as a result of adjuvant agent exposure. Since the recognition of ASIA syndrome, more than 4400 documented cases have been reported so far, illustrated by heterogeneous clinical manifestations and severity. In this review, five enigmatic conditions, including sarcoidosis, Sjögren's syndrome, undifferentiated connective tissue disease, silicone implant incompatibility syndrome (SIIS), and immune-related adverse events (irAEs), are defined as classical examples of ASIA. Certainly, these disorders have been described after an adjuvant stimulus (silicone implantation, drugs, infections, metals, vaccines, etc.) among genetically predisposed individuals (mainly the HLA-DRB1 and PTPN22 gene), which induce an hyperstimulation of the immune system resulting in the production of autoantibodies, eventually leading to the development of autoimmune diseases. Circulating autonomic autoantibodies in the sera of patients with silicone breast implants, as well as anatomopathological aspects of small fiber neuropathy in their skin biopsies have been recently described. To our knowledge, these novel insights serve as a common explanation to the non-specific clinical manifestations reported in patients with ASIA, leading to the redefinition of the ASIA syndrome diagnostic criteria.

Environmental factors in the pathogenesis of primary Sjögren's syndrome

Primary Sjögren's syndrome (SS) is a systemic autoimmune disease in which exocrine organs, primarily the salivary and lacrimal glands, are targets of chronic inflammation, leading to severe dryness of eyes and mouth. Fatigue and arthralgia are also common, and extraglandular manifestations involving the respiratory, nervous and vascular systems occur in a subset of patients. Persistent activation of the type I interferon system, and autoreactive B and T cells with production of disease-associated autoantibodies are central to the pathogenesis. Genetic polymorphisms that associate with an increased risk of SS have been described, though the risk-increase contributed by the respective variant is generally low. It is thus becoming increasingly clear that genetics cannot alone account for the development of SS and that other, presumably exogenous, factors must play a critical role. Relatively few studies have investigated exposure to potential risk factors prior to SS disease onset. Rather, many factors have been studied in prevalent cases. In this review, we summarize current literature on exogenous factors in the pathogenesis of SS including infections, hormones, smoking, solvents and additional compounds. We delineate for which factors there is current evidence of increased disease risk, and for which our present knowledge is confined to suggesting their role in SS pathogenesis. Finally, we outline future perspectives in the continued search for environmental risk factors for SS, a research area of great importance considering the possibilities for preventive measures.

Prevalence of Arthritis and Rheumatoid Arthritis in Coal Mining Counties of the United States

OBJECTIVE

Exposure to inhaled mineral dust, in particular silica, is associated with increased odds of rheumatoid arthritis (RA) and other autoimmune diseases. We studied the association of RA with work-related coal and silica exposure in the Appalachian region of the US.

METHODS

We carried out a random-digit dialed telephone survey in selected counties in Appalachia that had elevated coal workers' pneumoconiosis mortality. Our study cohort included men ages ≥50 with any employment history, and we assessed exposure to coal mining employment, other work-related dust, and ergonomic factors. We ascertained self-reported physician diagnosis of any arthritis and of RA with glucocorticoid treatment. We used multivariable logistic regression analysis to estimate the odds ratios (ORs) and associated population attributable fraction (PAF) estimates.

RESULTS

Among the 973 men who met study entry criteria (mean ± SD ages 66 ± 10 years; 54% ever smokers), 266 (27%) reported coal mining work and 189 (19%) reported other work-related silica exposure. There were 517 men (53%), who reported any arthritis and 112 (12%) whose disease met the study definition of RA. Adjusting for covariates, coal mining was associated with elevated odds of RA (OR 3.6 [95% confidence interval (95% CI) 2.1-6.2]), which accounted for a PAF of 33% (95% CI 26-40%) of the men studied. For any arthritis, the coal mining-associated OR was 2.3 (95% CI 1.6-3.2), with an associated PAF of 20% (95% CI 14-25%).

CONCLUSION

In this population of older males living in a coal mining region, we estimated that 20% of arthritis and 33% of RA may be attributable to coal mining work.

Genetic Associations and Environmental Exposures in the Aetiopathogenesis of Anti-Neutrophil Cytoplasmic Antibody- Associated Vasculitis: An Updated Review

Anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) represents a heterogeneous group of rare diseases characterised by necrotising inflammation of the small blood vessels and the presence of ANCA with specificity for proteinase-3 or myeloperoxidase. Genetic susceptibility along with malignancy, drug exposure, and environmental exposures to infectious agents and silica are involved in disease progression. To date, growing evidence has revealed that ANCA specificity defines homogeneous groups of patients more effectively than clinical diagnosis, since proteinase-3 ANCA and myeloperoxidase-ANCA are linked with different genetic backgrounds and epidemiologies. This review presents current and updated knowledge on the central aetiopathogenic role of genetic associations and environmental exposures in AAV; discusses the main mechanisms of ANCA immunogenesis; and highlights the value of ANCA specificity for future classification criteria.

Risk factors for the development of systemic sclerosis: a systematic review of the literature

OBJECTIVES

Although numerous studies have investigated the roles of various genetic, epigenetic and environmental factors that may impact its aetiology, SSc is still regarded as an idiopathic disease. Given that there is significant heterogeneity in what has been proposed to influence the development of SSc, this systematic review was conducted to assess the impacts of different factors on the aetiology of scleroderma.

METHODS

The search was performed in the PubMed, CINAHL and SCOPUS databases on 17 May 2017. Any study that made explicit reference to scleroderma or SSc that had information about the risk factors or epidemiology of the disease was included. The extracted outcome variables were prevalence, gender preponderance, geographical distribution, family history and various proposed environmental risk factors.

RESULTS

One thousand five hundred and seventy-four articles were screened for eligibility. Thirty-four articles were eligible for the systematic literature review.

CONCLUSION

Age between 45 and 64 years, female sex, positive family history and exposure to silica were found to be risk factors. There were conflicting findings regarding the impact of exposure to organic solvents and microchimerism. No relationship between infectious agents, alcohol consumption or cigarette smoking and the development of SSc was identified.

Environmental Basis of Autoimmunity

The three common themes that underlie the induction and perpetuation of autoimmunity are genetic predisposition, environmental factors, and immune regulation. Environmental factors have gained much attention for their role in triggering autoimmunity, with increasing evidence of their influence as demonstrated by epidemiological studies, laboratory research, and animal studies. Environmental factors known to trigger and perpetuate autoimmunity include infections, gut microbiota, as well as physical and environmental agents. To address these issues, we will review major potential mechanisms that underlie autoimmunity including molecular mimicry, epitope spreading, bystander activation, polyclonal activation of B and T cells, infections, and autoinflammatory activation of innate immunity. The association of the gut microbiota on autoimmunity will be particularly highlighted by their interaction with pharmaceutical agents that may lead to organ-specific autoimmunity. Nonetheless, and we will emphasize this point, the precise mechanism of environmental influence on disease pathogenesis remains elusive.

The global burden of SLE: prevalence, health disparities and socioeconomic impact

Systemic lupus erythematosus (SLE) is a multisystem autoimmune disease that can potentially lead to serious organ complications and even death. Its global burden - in terms of incidence and prevalence, differential impact on populations, economic costs and capacity to compromise health-related quality of life - remains incompletely understood. The reported worldwide incidence and prevalence of SLE vary considerably; this variation is probably attributable to a variety of factors, including ethnic and geographic differences in the populations being studied, the definition of SLE applied, and the methods of case identification. Despite the heterogeneous nature of the disease, distinct patterns of disease presentation, severity and course can often be related to differences in ethnicity, income level, education, health insurance status, level of social support and medication compliance, as well as environmental and occupational factors. Given the potential for the disease to cause such severe and widespread organ damage, not only are the attendant direct costs high, but these costs are sometimes exceeded by indirect costs owing to loss of economic productivity. As an intangible cost, patients with SLE are, not surprisingly, likely to endure considerably reduced health-related quality of life.

Overlap syndrome with Sjögren's syndrome and systemic sclerosis in a steel rolling mill worker: a case report

BACKGROUND

There are few reports about work-related factors associated with Sjögren's syndrome. We report a case of overlap syndrome with Sjögren's syndrome and systemic sclerosis.

CASE PRESENTATION

A 54-year-old man was admitted due to dyspnea on exertion. The results of physical examination and laboratory findings were compatible with Sjögren's syndrome with systemic sclerosis. The patient had no pre-existing autoimmune disease, and denied family history of autoimmune disease. The patient worked in the large-scale rolling department of a steel manufacturing company for 25 years. Hot rolling is a rolling process performed at between 1100 °C and 1200 °C, generating a high temperature and a large amount of fumes, involving jet-spraying of water throughout the process to remove the instantaneously generated oxide film and prevent the high generation of fumes. In this process, workers could be exposed to silica produced by thermal oxidation. Other potential toxic substances including nickel and manganese seemed to be less likely associated with the patient's clinical manifestations.

CONCLUSIONS

Occupational exposure to silica seemed to be associated with the patient's clinical manifestations of overlap syndrome with Sjögren's syndrome and systemic sclerosis. Although the underlying mechanism is still unclear, autoimmune disease including Sjögren's syndrome affects women more often than men and there was no family history of autoimmune disease. These suggested that there was an association between occupational silica exposure and the disease of the patient. Future research about the association between long-term low dose exposure to silica and the development of autoimmune diseases should be encouraged.

Silica, Silicosis, and Autoimmunity

Inhalation of dust containing crystalline silica is associated with a number of acute and chronic diseases including systemic autoimmune diseases. Evidence for the link with autoimmune disease comes from epidemiological studies linking occupational exposure to crystalline silica dust with the systemic autoimmune diseases systemic lupus erythematosus, systemic sclerosis, and rheumatoid arthritis. Although little is known regarding the mechanism by which silica exposure leads to systemic autoimmune disease, there is a voluminous literature on silica exposure and silicosis that may help identify immune processes that precede development of autoimmunity. The pathophysiology of silicosis consists of deposition of silica particles in the alveoli of the lung. Ingestion of these particles by macrophages initiates an inflammatory response, which stimulates fibroblasts to proliferate and produce collagen. Silica particles are encased by collagen leading to fibrosis and the nodular lesions characteristic of the disease. The steps in the development of silicosis, including acute and chronic inflammation and fibrosis, have different molecular and cellular requirements, suggesting that silica-induced inflammation and fibrosis may be mechanistically separate. Significantly, it is unclear whether silica-induced inflammation and fibrosis contribute similarly to the development of autoimmunity. Nonetheless, the findings from human and animal model studies are consistent with an autoimmune pathogenesis that begins with activation of the innate immune system leading to proinflammatory cytokine production, pulmonary inflammation leading to activation of adaptive immunity, breaking of tolerance, and autoantibodies and tissue damage. The variable frequency of these immunological features following silica exposure suggests substantial genetic involvement and gene/environment interaction in silica-induced autoimmunity. However, numerous questions remain unanswered.

Prospective risk of rheumatologic disease associated with occupational exposure in a cohort of male construction workers

BACKGROUND

The association between occupational exposure and autoimmune disease is well recognized for silica, and suspected for other inhalants. We used a large cohort to estimate the risks of rheumatoid arthritis, systemic lupus erythematosus, systemic sclerosis, and dermatomyositis associated with silica and other occupational exposures.

METHODS

We analyzed data for male Swedish construction industry employees. Exposure was defined by a job-exposure matrix for silica and for other inorganic dusts; those with other job-exposure matrix exposures but not to either of the 2 inorganic dust categories were excluded. National hospital treatment data were linked for International Classification of Diseases, 10(th) Revision-coded diagnoses of rheumatoid arthritis (seronegative and positive), systemic lupus erythematosus, systemic sclerosis, and dermatomyositis. The 2 occupational exposures were tested as independent predictors of prospective hospital-based treatment for these diagnoses using age-adjusted Poisson multivariable regression analyses to calculate relative risk (RR).

RESULTS

We analyzed hospital-based treatment data (1997 through 2010) for 240,983 men aged 30 to 84 years. There were 713 incident cases of rheumatoid arthritis (467 seropositive, 195 seronegative, 51 not classified) and 128 cases combined for systemic lupus erythematosus, systemic sclerosis, and dermatomyositis. Adjusted for smoking and age, the 2 occupational exposures (silica and other inorganic dusts) were each associated with increased risk of rheumatoid arthritis, systemic lupus erythematosus, systemic sclerosis, and dermatomyositis combined: RR 1.39 (95% confidence interval [CI], 1.17-1.64) and RR 1.31 (95% CI, 1.11-1.53), respectively. Among ever smokers, both silica and other inorganic dust exposure were associated with increased risk of rheumatoid arthritis (RRs 1.36; 95% CI, 1.11-1.68 and 1.42; 95% CI, 1.17-1.73, respectively), while among never smokers, neither exposure was associated with statistically significant increased risk of rheumatoid arthritis.

CONCLUSION

This analysis reaffirms the link between occupational silica and a range of autoimmune diseases, while also suggesting that other inorganic dusts may also impart excess risk of such disease.

Silicosis and chronic renal disease

BACKGROUND

Silica has been associated with end stage kidney disease and kidney dysfunction.

METHODS

Calculated glomerular filtration rate, history of kidney disease or chronic dialysis, elevated serum creatinine, and stages of chronic kidney disease among silicotics identified in Michigan's Silicosis Surveillance System from 1987 to 2009 were reviewed to determine the prevalence of kidney disease in confirmed cases of silicosis.

RESULTS

Twenty-four percent of 1,072 silicotics had a measure of kidney dysfunction (32.3% if diabetes or hypertension present vs. 20.2% if not). Sixty-nine percent of silicotics had Stage I or greater chronic kidney dysfunction versus 38.8% of the U.S. general population ≥60 years. No association was found between kidney function and measures of silica exposure.

CONCLUSIONS

Individuals with silicosis have an increased prevalence of kidney disease. More work to define the pathological changes associated with silica exposure is needed to understand the cause of silica's adverse effect on the kidney.

Primary Sjögren's syndrome and occupational risk factors: A case-control study

OBJECTIVES

A case-control study was carried out to investigate the relation between primary Sjögren's syndrome (pSS) and occupational exposure.

METHODS

One hundred seventy five cases of pSS followed up into the internal medicine departments of three French university hospitals from 2010 to 2013 were included. For each case, two age and gender matched controls were selected during the same period in the same departments. Occupational exposure was assessed retrospectively by industrial hygienists and occupational practitioners. Exposure to occupational factors such as organic solvents or silica was investigated using semiquantitative estimates of exposure. An exposure score was calculated for each subject based on probability, intensity, daily frequency, and duration of exposure for each period of employment. The final cumulative exposure score was obtained, taking into account all periods of employment.

RESULTS

Significant associations with pSS were observed for dichloromethane (OR 9.28, 95%CI 2.60-33.03), perchlorethylene (OR 2.64, 95%CI 1.20-5.77) chlorinated solvents (OR 2.95, 95%CI 1.77-4.93), benzene (OR 3.30, 95%CI 1.07-10.26), toluene (OR 4.18 95%CI 1.41-12.43), white spirit (OR 3.60, 95%CI 1.39-9.33), aromatic solvents (OR 3.03, 95%CI 1.41-6.50) and any types of solvents (OR 2.76, 95%CI 1.70-4.47). Risk of pSS was significantly associated with a high cumulative exposure score of occupational exposure to toluene (OR 4.69, 95%CI 1.42-15.45), white spirit (OR 3.30, 95%CI 1.07-10.26), aromatic solvents (OR 2.50, 95%CI 1.06-5.91) and any types of solvents (OR 2.25, 95%CI 1.20-4.22).

CONCLUSION

This work suggests the influence of occupational risk factors in the occurrence of pSS.

Sjögren's Syndrome and Silicosis - a Case Report

Sjögren’s syndrome is an autoimmune disease of unknown etiology where immune response to self-antigens is believed to result from interactions between genetic and environmental factors. We describe the case of a patient who has been diagnosed with Sjögren’s syndrome based on typical clinical and immunological parameters. The clinical picture was dominated by the respiratory symptoms, and radiographic and multislice computed tomography examination of the chest showed certain changes characteristic of pneumoconiosis. Given that the patient has worked in a foundry where he has been exposed to the silica dust, he was subject to examination by occupational health specialists under the suspicion of lung silicosis, who confirmed the silicosis. This case report points to the possible connection between a professional exposure to silica and Sjögren’s syndrome. Occupational exposure to silica is a possible risk factor for the development of autoimmune diseases, and in the evaluation of patients with connective tissue diseases it is important to consider work-related history.

Sjögren's syndrome: another facet of the autoimmune/inflammatory syndrome induced by adjuvants (ASIA)

Recently, a new syndrome, namely the "Autoimmune/inflammatory syndrome induced by adjuvants" (ASIA) has been defined. In this syndrome different conditions characterized by common signs and symptoms and induced by the presence of an adjuvant are included. The adjuvant is a substance capable of boosting the immune response and of acting as a trigger in the development of autoimmune diseases. Post-vaccination autoimmune phenomena represent a major issue of ASIA. Indeed, despite vaccines represent a mainstay in the improvement of human health, several of these have been implicated as a potential trigger for autoimmune diseases. Sjogren's Syndrome (SjS) is a systemic chronic autoimmune inflammatory disease characterized by the presence of an inflammatory involvement of exocrine glands accompanied by systemic manifestations. Own to the straight association between infectious agents exposure (mainly viruses) and sicca syndrome development, the possible link between vaccine and SjS is not surprising. Indeed, a few cases of SjS following vaccine delivery have been reported. At the same extent, the induction of SjS following silicone exposure has been described too. Thus, the aim of this review was to focus on SjS and its possible development following vaccine or silicone exposure in order to define another possible facet of the ASIA syndrome.

Occupational exposure in patients with the antisynthetase syndrome

Interstitial lung disease (ILD) is common in patients with myositis and is related with the presence of antisynthetase autoantibodies (aSA). Together with other manifestations, the resulting condition is known as the antisynthetase syndrome (ASS). Contact with certain environmental and occupational agents is also associated with the development of ILD. The objective of this study was to analyze occupational exposure and associated clinical manifestations in a cohort of patients with ASS. aSA had been identified by line immunoassay and confirmed by immunoprecipitation. Serial pulmonary function tests had been carried out to assess lung function. Thirty-two ASS patients and a control group of 32 myositis patients without aSA underwent a specific questionnaire interview to evaluate their cumulative exposure to biological dust, mineral dust, and gases/fumes up to disease onset. Comparisons were done with the Fisher exact test and Mann-Whitney test. Out from 32 ASS patients (median age, 42.7 yeras; IQR 32.2-52.5), twenty-six patients had anti-Jo-1, three anti-PL-12, and three anti-PL-7. Nine had polymyositis, 15 dermatomyositis, one amyopathic dermatomyositis, and seven pure ILD without myositis. Sixteen ASS patients (50 %) and seven (22 %) myositis patients without aSA had ever been highly exposed to dust, gases, or fumes (p < 0.05). A more than 10 % improvement in forced vital capacity occurred in 61 % of highly exposed patients and 23 % of those with low/no exposure (p = 0.06) over the observation period. In conclusion, a high percentage of patients with ASS had been exposed to dusts, gases, or fumes.

Silicone and scleroderma revisited

Silicone, a synthetic polymer considered to be a biologically inert substance, is used in a multitude of medical products, the most publicly recognized of which are breast implants. Silicone breast implants have been in use since the early 1960s for cosmetic and reconstructive purposes, and reports of autoimmune disease-like syndromes began appearing in the medical literature soon thereafter. Over the previous year, silicone implants have been suggested as playing a role in a new syndrome that encompasses a wide array of immune-related manifestations, termed ASIA ('Autoimmune Syndrome Induced by Adjuvant'). Scleroderma, a relatively rare connective tissue disease with skin manifestations and systemic effects, has also been described in association with silicone implantation and rupture. However, epidemiological studies and meta-analyses have failed to corroborate the clinical impression of silicone-induced scleroderma. The following review describes the mechanisms by which silicone may mediate autoimmunity in general, as well as the evidence for causal associations with more specific autoimmune syndromes in general, and scleroderma in particular.

Air pollution in autoimmune rheumatic diseases: a review

Air pollution consists of a heterogeneous mixture of gasses and particles that include carbon monoxide, nitrates, sulfur dioxide, ozone, lead, toxic by-product of tobacco smoke and particulate matter. Oxidative stress and inflammation induced by inhaled pollutants may result in acute and chronic disorders in the respiratory system, as well as contribute to a state of systemic inflammation and autoimmunity. This paper reviews the mechanisms of air contaminants influencing the immune response and autoimmunity, and it focuses on studies of inhaled pollutants triggering and/or exacerbating rheumatic diseases in cities around the world. Remarkably, environmental factors contribute to the onset of autoimmune diseases, especially smoking and occupational exposure to silica in rheumatoid arthritis and systemic lupus erythematosus. Other diseases such as scleroderma may be triggered by the inhalation of chemical solvents, herbicides and silica. Likewise, primary vasculitis associated with anti-neutrophil cytoplasmic antibody (ANCA) may be triggered by silica exposure. Only few studies showed that air pollutants could trigger or exacerbate juvenile idiopathic arthritis and systemic lupus erythematosus. In contrast, no studies of tropospheric pollution triggering inflammatory myopathies and spondyloarthropathies were carried out. In conclusion, air pollution is one of the environmental factors involved in systemic inflammation and autoimmunity. Further studies are needed in order to evaluate air pollutants and their potentially serious effects on autoimmune rheumatic diseases and the mechanisms involved in the onset and the exacerbation of these diseases.

Prevalence of connective tissue disease in silicosis (1985-2006)-a report from the state of Michigan surveillance system for silicosis

BACKGROUND

The risk of developing clinical connective tissue disease (CTD) has been reported to be increased among individuals with silica exposure.

METHODS

We reviewed the medical records of individuals reported to the Michigan Silicosis Surveillance system from 1985 to 2006 to confirm the diagnosis of silicosis and determine the presence of CTDs.

RESULTS

From 1985 to 2006, 1,022 cases were confirmed to have silicosis. Medical records of 790 cases were available. Thirty-three individuals had rheumatoid arthritis (RA) [prevalence 4.2% (prevalence ratio (RR) ranged from 2.26, 95% CI: 1.57-3.25 to 6.96, 95% CI: 2.93-16.53) depending on the reference rate used], two had scleroderma [prevalence 0.3% (RR 28.3, 95% CI: 6.09-129.98)], one had systemic lupus erythematosus [prevalence 0.1% (RR 2.53, 95% CI: 0.30-21.64)], two had Sjogrens syndrome [prevalence 0.3% (RR 0.42, 95% CI: 0.09-2.08)], and six had anti-neutrophil cytoplasm antibody (ANCA) vasculitis [prevalence 0.8% (RR 25.3, 95% CI: 6.34-101.04)]. There was no difference between those with and without CTD with respect to age, race, industry type, history of tuberculosis, application for workers' compensation, or severity of fibrotic changes on chest X-ray.

CONCLUSIONS

A two- to eightfold risk for RA and systemic lupus erythematosus, with a greater than 24-fold risk for scleroderma and ANCA vasculitis was found in individuals with silicosis. The most common CTD among silicotics in the Michigan disease registry was RA. Though not classically included in the category of CTD, ANCA-associated vasculitis was found to have a much greater prevalence amongst silicosis patients than the general population.

Goodpasture's Syndrome and Silica: A Case Report and Literature Review

We report a case of Goodpasture's syndrome following chronic low level and an acute, high level of exposure to crystalline silica. A 38-year-old male tilesetter was admitted to the emergency room with dyspnea and respiratory failure. He reported that his symptoms had developed over the previous week after inhaling a large amount of dust while dry-sanding and sweeping a silica-based product used to fill cracks in a cement floor. Over the following days, his pulmonary function declined and he developed acute renal failure. Tests of antiglomerular basement membrane antibody were positive and renal biopsy revealed global glomerulonephritis. He was diagnosed with Goodpasture's syndrome and treated with steroids, plasmapheresis, and hemodialysis. This man had a history of childhood asthma and a remote, one pack-year history of cigarette use. He used the flooring product for seven years prior to the inciting event, however, previous jobs had utilized significantly smaller amounts. Goodpasture's syndrome and other autoimmune diseases have been reported in association with silica exposure. The acute onset following high level silica exposure in this previously healthy man, suggest that clinicians should investigate silica exposure as a causal factor in cases of Goodpasture's syndrome.

Antinuclear antibody and rheumatoid factor in silica-exposed workers

A lot of workers in industries such as foundry, stonecutting, and sandblasting are exposed to higher than permissible levels of crystalline silica. Various alterations in humoral immune function have been reported in silicosis patients and workers exposed to silica dust. The aim of this study was to measure antinuclear antibody (ANA) and rheumatoid factor (RF) levels in foundry workers exposed to silica and to compare them with a control group without such exposure. ANA and RF were measured in 78 exposed and 73 non-exposed workers, and standard statistical methods were used to compare them. The two groups did not significantly differ in age and smoking. Mean work duration of the exposed and non-exposed workers was (14.9+/-4.72) years and (12.41+/-6.3) years, respectively. Ten exposed workers had silicosis. ANA was negative in all workers in either group. Its mean titer did not differ significantly between the exposed and control workers [(0.39+/-0.15) IU mL(-1) vs. (0.36+/-0.17) IU mL(-1), respectively]. RF was positive in two workers of each group. Other studies have reported an increase in ANA and RF associated with exposure to silica dust and silicosis.In contrast, our study suggests that exposure to silica dust does not increase the level of ANA and RF in exposed workers.

Changes of cytokine production and cell viability of peripheral blood mononuclear cells from silicosis patients: effect of in vitro treatment with acetylsalicylic acid

In this study, IL-6 and IL-12p40 production and cell viability of peripheral blood mononuclear cells from silicosis patients after in vitro stimulation were investigated. Furthermore, the effects of introducing acetylsalicylic acid to stimulated patients’ peripheral blood mononuclear cells on cytokine production and cell viability were determined. Nine patients with moderate silicosis, 11 with severe silicosis and 14 healthy subjects were recruited for this study. The level of IL-6 produced by patients peripheral blood mononuclear cells decreased depending on the stage of the disease. The addition of acetylsalicylic acid had significantly suppressive effect on the IL-6 production by lipopolysaccharide—stimulated patients’ peripheral blood mononuclear cells. Acetylsalicylic acid treatment of C3 binding glycoprotein—stimulated patients’ peripheral blood mononuclear cells led to significant upregulation of IL-12p40 production. Results showed a stage-dependent decrease of cell viability of peripheral blood mononuclear cells from silicosis patients. Acetylsalicylic acid significantly decreased cell viability entirely in stimulated peripheral blood mononuclear cells from patients with severe silicosis. In conclusion, this study showed that the disease progression affects peripheral blood mononuclear cells in patients with silicosis and causes functional changes that became apparent after stimulation. Our study demonstrated that in severe silicosis the treatment with acetylsalicylic acid, as an anti-inflammatory agent, might not be beneficial for patients.

Systemic sclerosis: environmental factors

Epidemiological evidence for the association between environmental and occupational risk factors and systemic sclerosis (SSc) has been extensively analyzed. Such exposures are frequently of long duration, and the inadequate classification of the type of exposure and other confounding variables may bias their estimated association with SSc. Environmental factors could be classified as occupational (silica, organic solvents), infectious (bacterial, viral), and non-occupational/non-infectious (drugs, pesticides, silicones). Understanding the link between environmental risk factors and the development of SSc is limited, due to the phenotypic and pathogenic heterogeneity of patients and disease, respectively, and also due to poor ability to assess environmental exposures quantitatively and the role of the gene-environment interactions in this disease. Global collaboration could increase the chance for a better use of the data obtained from a limited number of cases and also limited resources. Normalization and validation of biomarkers and questionnaires could also be very useful to reliably quantify environmental exposures.

Pneumoconiose reumatoide (síndrome de Caplan) com apresentação clássica

Apesar de rara, a pneumoconiose reumatoide, também chamada de síndrome de Caplan, pode ser diagnosticada entre trabalhadores expostos à sílica e entre pacientes com silicose, pneumoconiose dos mineiros de carvão e asbestose. A maior prevalência ocorre entre os silicóticos, apesar de ter sido descrita inicialmente em mineiros de carvão com pneumoconiose. O achado que define o tipo clássico da síndrome é a presença de nódulos reumatoides nos pulmões, independente da presença ou não de pequenas opacidades pneumoconióticas, ou de grandes opacidades de fibrose pulmonar maciça, associada ou não a um quadro de artrite reumatoide em atividade. Relatamos o caso de uma mulher com quadro de artrite reumatoide, diagnosticada 34 anos após exposição à sílica livre em uma indústria de porcelana por 7 anos, apresentando radiograma de tórax com opacidades arredondadas de 1 a 5 cm de diâmetro, distribuídas na periferia de ambos os pulmões. A biópsia transtorácica guiada por TC de um dos nódulos revelou tratar-se de nódulo reumatoide com macrófagos em paliçada, típico da síndrome de Caplan. São discutidos aspectos de diagnóstico da síndrome, classificação e ocorrência, ressaltando a importância da anamnese ocupacional em casos de artrite reumatoide com opacidades radiológicas pulmonares.

Occupational exposures and risk of systemic lupus erythematosus

This review summarizes the growing body of epidemiologic and experimental research pertaining to the relationship between SLE and occupational exposures, such as crystalline silica, solvents, and pesticides. Epidemiologic studies, using different designs in different settings, have demonstrated moderate to strong associations between occupational silica exposure and SLE. Recent experimental studies of silica in lupus-prone mice provide support for the idea that, in addition to its known adjuvant effect, silica exposure increases the generation of apoptotic material, an important source of self-antigen. Despite compelling experimental studies of the organic solvent trichloroethylene (TCE) in lupus-prone mice, there is little evidence of an overall association of SLE and occupational exposure to a broad classification of solvents in humans. However, there is a lack of data on SLE in occupational cohorts with exposures to TCE or other specific solvents. One epidemiologic study reported an association of pesticide mixing and SLE, while a recent experimental study reported accelerated disease in pesticide-treated lupus-prone mice. Other occupational exposures worth investigating include asbestos, metals, and UV radiation. Attention should also be given to the role of gene-environment interactions, which may require large, multi-site studies that collect both genetic material and occupational exposure data. The quality of exposure assessment is an important consideration in designing and evaluating these studies. The use of pre-clinical endpoints (e.g. high-titer autoantibodies) in occupational cohorts with well-characterized exposure histories may reveal occupational risk factors for autoimmunity, and may also provide baseline data for studies of determinants of progression to SLE.

State-of-the-science review of the occupational health hazards of crystalline silica in abrasive blasting operations and related requirements for respiratory protection

Excessive exposures to airborne crystalline silica have been known for over 100 years to pose a serious health hazard. Work practices and regulatory standards advanced as the knowledge of the hazards of crystalline silica evolved. This article presents a comprehensive historical examination of the literature on exposure, health effects, and personal protective equipment related to silica and abrasive blasting operations over the last century. In the early 1900s, increased death rates and prevalence of pulmonary disease were observed in industries that involved dusty operations. Studies of these occupational cohorts served as the basis for the first occupational exposure limits in the 1930s. Early exposure studies in foundries revealed that abrasive blasting operations were particularly hazardous and provided the basis for many of the engineering control and respiratory protection requirements that are still in place today. Studies involving abrasive blasters over the years revealed that engineering controls were often not completely effective at reducing airborne silica concentrations to a safe level; consequently, respiratory protection has always been an important component of protecting workers. During the last 15-20 yr, quantitative exposure-response modeling, experimental animal studies, and in vitro methods were used to better understand the relationship between exposure to silica and disease in the workplace. In light of Occupational Safety and Health Administration efforts to reexamine the protectiveness of the current permissible exposure limit (PEL) for crystalline silica and its focus on protecting workers who are known to still be exposed to silica in the workplace (including abrasive blasters), this state-of-the-science review of one of the most hazardous operations involving crystalline silica should provide useful background to employers, researchers, and regulators interested in the historical evolution of the recognized occupational health hazards of crystalline silica and abrasive blasting operations and the related requirements for respiratory protection.

Hypotheses on the etiology of antineutrophil cytoplasmic autoantibody associated vasculitis: the cause is hidden, but the result is known

The first description of what is now known as antineutrophil cytoplasmic autoantibody-associated necrotizing vasculitis appeared more than 140 yr ago. Since then, many aspects of the pathogenic pathway have been elucidated, indicating the involvement of antineutrophil cytoplasmic autoantibodies, but why antineutrophil cytoplasmic autoantibodies are produced in the first place remains unknown. Over the years, many hypotheses have emerged addressing the etiology of antineutrophil cytoplasmic antibody production, but no exclusive factor or set of factors can so far be held responsible. Herein is reviewed the most influential hypotheses regarding the causes of antineutrophil cytoplasmic antibody-associated vasculitis with the aim of placing in an epidemiologic background the different hypotheses that are centered on environmental and genetic influences.

Occupational exposures and risk of systemic lupus erythematosus: a review of the evidence and exposure assessment methods in population- and clinic-based studies

Epidemiologic and experimental research suggests a potential role of occupational exposures in the development of systemic lupus erythematosus (SLE). A plausible association has been identified in studies of occupational silica exposure and SLE, complemented by experimental studies in lupus-prone mice exploring potential mechanisms related to apoptosis and immune dysregulation. Experimental studies of the solvent trichloroethylene in lupus-prone mice provide evidence of effects on immune function, including increased production of autoantibodies and activation of CD4+ T cells. However, few studies of occupational solvent exposure and SLE have been conducted, and those that are available show little evidence of an association. There is some suggestion from the available studies of the potential influence of pesticides on SLE, but as with solvents, the specific type of pesticides that may be implicated is not known. Our understanding of the role of occupational exposures in SLE could be advanced by the development of larger, multisite or parallel studies that utilize similar questionnaire and exposure evaluation methods. Multiple studies using comparable exposure measures are needed to provide sufficient sample size for examining gene-environment interactions. We provide a general overview of data requirements and methods available for the assessment and evaluation of occupational exposures in clinical and population-based studies of SLE.

CD8+ T lymphocytes infiltrate predominantly in the inflammatory foci of MPO-ANCA-positive thoracic hypertrophic pachymeningitis in a patient with HLA-A24

Hypertrophic pachymeningitis (HP) is extremely rare and an inflammatory process that thickens the dura mater. A 59-year-old Japanese woman developed backache, became paraplegic, and magnetic resonance imaging revealed diffuse thickening of the thoracic dura mater encompassing the spinal cord. Although a test for myeloperoxidase antineutrophil cytoplasmic autoantibody (MPO-ANCA) was shown to be positive, vasculitis was not found and CD8(+) T lymphocytes that predominated in the inflammatory foci. Both interleukin (IL)-2 and IL-6 were markedly elevated in not only sera but also cerebrospinal fluids, very much higher in the latter. Human leukocyte antigen (HLA) typing revealed A24 positivity, suggesting this molecule was interacting with CD8(+) T lymphocytes. It was suggested that immunological disharmony and autoimmunity would play a pivotal role in the development of HP under genetic background of HLA-A24, and HP would be one feature of multiple organ involvement in ANCA-associated diseases.

Silica-associated systemic lupus erythematosus in an elderly man

The predominantly young woman-orientated systemic lupus erythematosus (SLE) is a disease that involves an extremely complicated and multifactorial interaction of various genetic and environmental factors. Crystalline silica (Si) may act as an immunoadjuvant to increase secretions of inflammatory endogenous substances and antibody production. In addition, previous studies have suggested that exposure to Si may induce SLE. Although the biologic mechanism of Si in SLE is unclear, defective apoptosis leading to the prolonged survival of pathogenic lymphocytes was thought to be one of mechanisms of Si-associated SLE (sSLE). In the present study, a rare case of an elderly man suffering from sSLE responded well to glucocorticoid therapy. The present findings were reviewed with reference to previous literature.

Environment and systemic lupus erythematosus: an overview

Systemic lupus erythematosus (SLE) is an autoimmune disease of unknown etiology that manifests as a pleomorphic systemic disease mainly affecting females. The variety of autoantibodies found in the serum of patients indicate that SLE is an autoimmune disease, but the mechanisms leading to the aberrant responses are not clearly understood although it is thought that a number of genetic and environmental factors may be involved. Environmental (or non-genetic) exposures could include infectious agents, chemicals or other compounds capable of modulating immune responses such as occupational/environmental pollutants or drugs, and behavioural factors such as smoking and diet. Environmental exposures may lead to the production of autoreactive T cells and autoantibodies, the stimulation of pro- and antiinflammatory cytokines, and target end-organ damage, but are not so convincing as agents causing SLE. Exposure to viruses increases antibody titres, but these may be the result of polyclonal B cell activation. The amount and timing of exposure to different environmental factors may play a significant and complex role in the pathogenesis of SLE and other autoimmune diseases. A better understanding of the etiopathogenetic mechanism of SLE is required in order to clarify the multiple interactions between environmental exposures and genetic factors.

Occupational silica and solvent exposures and risk of systemic lupus erythematosus in urban women

OBJECTIVE

To assess the risk of systemic lupus erythematosus (SLE) associated with occupational exposure to silica dust and organic solvents in an urban population.

METHODS

Women with SLE were identified through both community screening and hospital databases in 4 predominantly African American neighborhoods in Boston. Female control patients were volunteers from the same communities and were screened for the absence of connective tissue disease. Demographic factors, smoking history, and a detailed occupational history, including exposures to specific chemicals, were obtained by in-person interviews. The exposure assessment was based on independent evaluation of the occupational history by 2 reviewers who were blinded to each subject's disease status. The risks associated with exposure to silica and solvents were analyzed using multivariate conditional logistic regression models, adjusted for potential confounders.

RESULTS

Ninety-five patients and 191 age- and race-matched controls were included in this analysis. Exposure to silica for longer than 1 year was associated with SLE (odds ratio [OR] 4.3, 95% confidence interval [95% CI] 1.7-11.2). An exposure-response effect was seen for longer duration of exposures to silica (P for trend = 0.01). The association between occupational exposure to organic solvents and SLE was not statistically significant (OR 1.04, 95% CI 0.34-3.2).

CONCLUSION

Silica exposure from a variety of industrial occupations in urban areas is associated with an increased risk of SLE. A longer duration of exposure to silica dust is associated with greater risks. This study provides further impetus for additional research into the influence of modifiable exposures on the pathogenesis of SLE.