The association between silica exposure and development of ANCA-associated vasculitis: systematic review and meta-analysis

Prevalence and Clinical Impact of Systemic Autoimmune Rheumatic Disease in Patients with Silicosis

BACKGROUND

Silicosis is associated with an increased risk of developing systemic autoimmune rheumatic disease (SARD). The prognostic implications of this association are poorly characterized. The aim of this study was to determine the prevalence of SARD and autoimmune markers in a cohort of patients with exposure to silica and assess their impact on prognosis.

METHOD

We performed a prospective observational study of all patients attending the dedicated silicosis clinic of our pulmonology unit between 2009 and December 2017. Diagnosis was confirmed by a rheumatologist according to Spanish Rheumatology Society criteria. Autoimmune markers, pulmonary function tests, radiological progression, visits to the emergency department and primary care center, and hospital admissions for respiratory causes, and mortality were analyzed.

RESULTS

Overall, 489 cases of silicosis and 95 cases of exposure were studied. In total, 54 (11.0%) patients with silicosis had SARD: 12 (2.4%) rheumatoid arthritis, 10 (2.0%) systemic lupus erythematosus, 10 (2.0%) systemic sclerosis, 3 (0.6%) Sjögren syndrome, 2 (0.4%) vasculitis associated with anti-neutrophil cytoplasmic antibodies (ANCA +), 6 (1.2%) psoriatic arthritis, 3 (0.6%) ankylosing spondylitis, and 8 (1.6%) other autoimmune diseases with no special features. The patients with SARD visited the emergency room more often (63.0 vs. 42.5%; p = 0.004), and progressed more rapidly (22.2 vs. 11.7%; p = 0.030).

CONCLUSIONS

The presence of systemic rheumatic autoimmune diseases involves radiological progression and a higher clinical impact.

Renal involvement in a silicosis patient - case report and literature review

A 43-year-old Chinese man with a silicosis history was admitted to our hospital due to bilateral lower extremity edema for 1 year, exacerbating with hematuria for 2 months. He started working as a coal miner 30 years ago, and was diagnosed as silicosis 3 months ago. Lab tests revealed hematuria 3+, proteinuria 3+, and a serum creatinine value 2.47 mg/dl on routine check. He was diagnosed with focal proliferative IgA nephropathy (IgAN) and acute tubulo-interstitial nephritis by renal biopsy. He was treated with corticosteroids and got a remission 4 months later. Immunohistochemical staining showed the deposition of macrophage receptor with collagenous structure (MARCO), nod-like receptor pyrin domain-containing-3 (NLRP3), Caspase-1, apoptosis-associated speck (ASC), interleukin (IL)-1β, and IL-18 in both glomerular and tubulo-interstitial areas. We proposed that the silicon exposure could be related to his kidney disease in the patient and NLRP3 mediated inflammation might be involved in its pathogenesis which needs further explorations.

ANCA associated vasculitis

Vasculitis is characterized by inflammation of the vascular wall. It reaches vessels of different sizes and locations, conditioning multisystem and complex manifestations that require a holistic approach. Antineutrophil cytoplasmic antibody-associated vasculitis has an annual incidence rate of 20 per million inhabitants. It is the result of the interaction of infectious, genetic and environmental factors and manifest itself with varied and unspecific symptoms, often reaching the general state, respiratory and renal systems. The combination of clinical, laboratory, imaging and fundamentally histological changes allows the diagnosis and classification of the extent / severity of the disease necessary for the decision of the therapeutics to be taken. Glucocorticoids are generally used; with methotrexate being considered when localized disease and cyclophosphamide, rituximab or azathioprine when generalized disease. A systematized approach can increase survival rates from 12% to 70% over a 5-year span.

Updates in antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis for the ENT surgeon

ENT involvement is common in ANCA-associated vasculitis (AAV), particularly in GPA and EGPA. Early recognition and treatment is important for good outcomes, yet evidence suggests that UK ENT surgeons may not consistently recognise the early features of AAV, despite a similar incidence to vestibular schwannoma. AAV is a rapidly advancing field, with significant developments in the understanding of its pathogenesis, classification and treatment over the past decade. Relevant vasculitis mimics are also discussed with a particular focus on the increasing prevalence of vasculitis mimics driven by an increase in recreational cocaine use, as well as the emergence and reclassification of several other vasculitis mimics in the head and neck. This article reviews key recent updates in the vasculitis literature, with a particular focus on those relevant to recognition and diagnosis of AAV for the ENT surgeon. Strengths and limitations of relevant diagnostic testing are discussed, and a method of evaluation of patients with features of AAV presenting to ENT services is outlined.

Personalized Medicine in ANCA-Associated Vasculitis ANCA Specificity as the Guide?

Anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is a small- to medium-vessel necrotizing vasculitis responsible for excess morbidity and mortality (1). The AAVs, which include granulomatosis with polyangiitis (GPA), microscopic polyangiitis (MPA), and eosinophilic granulomatosis with polyangiitis (EGPA), are among the most difficult types of vasculitis to treat. Although clinicopathologic disease definitions have been used traditionally to categorize patients into one of these three diagnoses, more recently ANCA specificity for either proteinase 3 (PR3) or myeloperoxidase (MPO) has been advocated for the purpose of disease classification (2). This is because differences in genetics, pathogenesis, risk factors, treatment responses, and outcomes align more closely with PR3- or MPO-ANCA type than with the clinocopathologic diagnosis. Moreover, classifying patients as GPA or MPA can be challenging because biopsies are not obtained routinely in most cases and existing classification systems can provide discrepant classification for the same patient (3). In this review, we address the recent literature supporting the use of ANCA specificity to study and personalize the care of AAV patients (Table 1). We focus particularly on patients with GPA or MPA.

Eosinophilic Granulomatosis with Polyangiitis: Clinical Pathology Conference and Review

Eosinophilic granulomatosis with polyangiitis (EGPA) (formerly Churg-Strauss syndrome) is a small vessel vasculitis associated with asthma and eosinophilia. Despite its rarity, continuous gains are being made in understanding the disease with knowledge advancements regarding its epidemiology, heterogeneous clinical manifestations, management, and outcomes. Large knowledge gaps remain, however, particularly surrounding pathophysiologic and diagnostic uncertainties. There is still an incomplete understanding of the interplay between the eosinophilic and vasculitic processes that are features of disease pathogenesis. EGPA is also a conceptually difficult disorder given its dual categorization with hypereosinophilic syndromes and systemic vasculitides and the absence of a biomarker that can reliably distinguish between the two. In addition, recent evidence points to distinct, but partly overlapping, disease phenotypes, yet there is insufficient understanding to inform phenotype-tailored therapies. EGPA also remains a diagnostic challenge in part because asthma may be the primary or predominant manifestation for years, and the chronic corticosteroid requirement may mask other disease features. Efforts are ongoing to better elucidate pathophysiologic mechanisms, resolve classification issues, better characterize disease manifestations, and further clarify disease subcategorization, all of which will translate into better diagnosis and treatment with the possibility of specifically adapted therapies.

Temporal and Cartographic Analyses of the Distribution within Spain of Mortality Due to Granulomatosis with Polyangiitis (1984⁻2016)

The aim is to conduct a descriptive, population-based study in order to assess temporal and spatial changes in mortality due to granulomatosis with polyangiitis (GPA) in Spain from 1984 to 2016. Mortality data were obtained from the Spanish Annual Death Registry. Deaths in which GPA was the underlying cause were selected using the 446.4 and M31.3 codes from the International Classification of Diseases, 9th and 10th revision. Annual average age at death and age-adjusted mortality rates were calculated. Geographic analysis was performed at municipality and district level. Variations in mortality according to the type of municipality (urban, agro-urban or rural), district and geographic location (degrees of latitude) were assessed using standardized mortality ratios (SMRs) and smoothed-SMRs. Over the whole period, 620 deaths due to GPA were identified. Age at death increased at an average annual rate of 0.78% over the period 1987–2016 (p < 0.05). Age-adjusted mortality rates increased by an annual average of 20.58% from 1984 to 1992, after which they fell by 1.91% a year (p < 0.05). The agro-urban category had the highest percentage (4.57%) of municipalities with a significantly higher GPA mortality rate than expected. Geographic analysis revealed four districts with a higher risk of death due to GPA, two in the North of Spain and two in the South. This population-based study revealed an increase in the age at death attributed to GPA. Age-adjusted mortality rates went up sharply until 1992, after which they started to decline until the end of the study period. Geographic differences in mortality risk were identified but further studies will be necessary to ascertain the reasons for the distribution of GPA disease.

Mepolizumab as the first targeted treatment for eosinophilic granulomatosis with polyangiitis: a review of current evidence and potential place in therapy

Mepolizumab is an anti-interleukin-5 (IL-5) humanized monoclonal antibody that binds to free IL-5. It induces bone marrow eosinophil maturation arrest and decreases eosinophil progenitors and subsequent maturation in the blood and bronchial mucosa. Its use has been extensively studied in severe eosinophilic asthma at a dose of 100 mg subcutaneously (SC) every 4 weeks and, more recently, in other hypereosinophilic syndromes. Eosinophilic granulomatosis with polyangiitis (EGPA) is an eosinophilic vasculitis that may involve multiple organs. Characteristic clinical manifestations are asthma, sinusitis, transient pulmonary infiltrates and neuropathy. Among the numerous pathways involved in the pathogenesis of EGPA, the Th-2 phenotype has a main role, as suggested by the prominence of the asthmatic component, in triggering the release of key cytokines for the activation, maturation and survival of eosinophils. In particular, IL-5 is highly increased in active EGPA and its inhibition can represent a potential therapeutic target. In this scenario, mepolizumab may play a therapeutic role. After some positive preliminary observations on the use of mepolizumab in small case series of EGPA patients with refractory or relapsing disease despite standard of care treatment, a randomized controlled trial was published in 2017. Mepolizumab at a dose of 300 mg administered by SC injection every 4 weeks proved effective in prolonging the period of remission of the disease, allowing for reduced steroid use. The positive results of this study, which met both of the primary endpoints, led to the approval in the USA of mepolizumab in adult patients with EGPA by the Food and Drug Administration in 2017. Therefore, mepolizumab can be officially considered as an add-on therapy with steroid-sparing effect in cases of relapsing or refractory EGPA. However, the most appropriate dose and duration of therapy still need to be determined. Future studies on larger multinational populations with prolonged follow-up are warranted.

The Burden of Silicosis in Michigan: 1988-2016

RATIONALE

Exposure to respirable crystalline silica causes silicosis, a preventable, progressive occupational lung disease. A more rigorous occupational health standard for silica could help protect silica-exposed workers.

OBJECTIVES

To describe trends over 29 years of silicosis surveillance in Michigan.

METHODS

Michigan law requires the reporting of silicosis. We confirmed the diagnosis of silicosis in reported cases using medical questionnaires, review of medical records, and chest radiographs. The Michigan Occupational Safety and Health Administration (OSHA) conducted enforcement inspections at the workplaces of the silicosis cases, including air monitoring for silica and evaluation of workplace medical surveillance programs.

RESULTS

The Michigan surveillance program identified 1,048 silicosis cases from 1988 to 2016, which decreased from 620 during 1988-1997, to 292 during 1998-2007, to 136 during 2008-2016. The cumulative incidence rate of silicosis decreased from 3.7 to 1.4 to 0.7 cases per 100,000 men 40 years of age and older in Michigan over the same three periods. African Americans had a higher cumulative incidence rate of silicosis, with 6.0 cases per 100,000 African American men 40 years of age and older in Michigan compared with 1.2 cases per 100,000 white men 40 years of age and older in Michigan. The cases identified had severe disease; 59% had progressive massive fibrosis or category 2 or 3 small opacities per B-reading classification of the chest radiograph. Seventeen percent reported ever having active tuberculosis. On spirometry, 76% of ever smokers and 72% of never smokers demonstrated either a restrictive or an obstructive pattern. Most (65%) had not applied for workers' compensation benefits; the percentage who applied for benefits decreased from 42% to 28-16% over the three periods. Thirty-four of 55 (62%) workplace inspections found exposures above the new OSHA 50 μg/m3 respirable crystalline silica permissible exposure limit, and only 11% of inspected companies screened their workers for silicosis.

CONCLUSIONS

Adults with confirmed cases of silicosis have advanced disease and morbidity. Most are not using workers' compensation to pay for their care. The new OSHA silica standard, which lowers the permissible exposure limit for silica and requires medical monitoring to identify workers with silicosis, will help reduce the burden of silica exposure. It is critical for pulmonologists to be vigilant to recognize and manage this preventable occupational lung disease.

Pathogenesis of ANCA-Associated Pulmonary Vasculitis

Antineutrophil cytoplasmic antibodies (ANCAs) are autoantibodies specific for antigens located in the cytoplasmic granules of neutrophils and lysosomes of monocytes. ANCAs are associated with a spectrum of necrotizing vasculitis that includes granulomatosis with polyangiitis, microscopic polyangiitis, and eosinophilic granulomatosis with polyangiitis. Pulmonary vasculitis and related extravascular inflammation and fibrosis are frequent components of ANCA vasculitis. In this review, we detail the factors that have been associated with the origin of the ANCA autoimmune response and summarize the most relevant clinical observations, in vitro evidence, and animal studies strongly indicating the pathogenic potential of ANCA. In addition, we describe the putative sequence of pathogenic mechanisms driven by ANCA-induced activation of neutrophils that result in small vessel necrotizing vasculitis and extravascular granulomatous necrotizing inflammation.

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.

The frequency of ANCA-associated vasculitis in a national database of hospitalized patients in China

BACKGROUND

Anti-neutrophil cytoplasmic autoantibody (ANCA)-associated vasculitis (AAV) is a group of life-threatening autoimmune diseases. The epidemiological data on AAV in China are limited. The aim of the present study is to investigate the frequency, geographical distribution, and ethnic distribution of AAV in hospitalized patients in China, and its association with environmental pollution.

METHODS

We investigated the hospitalized patients in a national inpatient database covering 54.1% tertiary hospitals in China from 2010 to 2015. Diagnosis of AAV was extracted according to the definition of International Classification of Diseases (ICD)-10 codes and free text. Variables from the front page of inpatient records were collected and analyzed, including frequency, geographic distribution, demographic characteristics and seasonal variations of AAV. The association between various environmental pollutants and frequency of AAV was further analyzed.

RESULTS

Among 43.7 million inpatients included in the study period, 0.25‰ (10,943) were diagnosed as having AAV. The frequency of AAV was relatively stable during the study period (from 0.34‰ in 2010 to 0.27‰ in 2015). The proportion of AAV increased with latitude (0.44‰ in Northern China and 0.27‰ in Southern China in 2015). Hospitalizations were mostly observed in winter (30.2%). The Dong population, an ethnic minority of the Chinese population, had the highest frequency of patients with AAV (0.67‰). We also found a positive association between the exposure to carbon monoxide and the frequency of AAV (R² = 0.172, p = 0.025). In Yunnan province, the frequency of AAV increased 1.37-fold after the Zhaotong earthquake, which took place in 2014.

CONCLUSIONS

Our present investigation of hospitalized patients provided epidemiological information on AAV in China for the first time. A spatial and ethnic clustering trend and an association between pollution and the frequency of AAV were observed.

Review of Non-Respiratory, Non-Cancer Physical Health Conditions from Exposure to the World Trade Center Disaster

After the World Trade Center attacks on 11 September 2001 (9/11), multiple cohorts were developed to monitor the health outcomes of exposure. Respiratory and cancer effects have been covered at length. This current study sought to review the literature on other physical conditions associated with 9/11-exposure. Researchers searched seven databases for literature published in English from 2002 to October 2017, coded, and included articles for health condition outcome, population, 9/11-exposures, and comorbidity. Of the 322 titles and abstracts screened, 30 studies met inclusion criteria, and of these, 28 were from three cohorts: the World Trade Center Health Registry, Fire Department of New York, and World Trade Center Health Consortium. Most studies focused on rescue and recovery workers. While many of the findings were consistent across different populations and supported by objective measures, some of the less studied conditions need additional research to substantiate current findings. In the 16 years after 9/11, longitudinal cohorts have been essential in investigating the health consequences of 9/11-exposure. Longitudinal studies will be vital in furthering our understanding of these emerging conditions, as well as treatment effectiveness.

Incidence of anti-neutrophil cytoplasmic antibody-associated vasculitis before and after the February 2011 Christchurch Earthquake

BACKGROUND

It has been suggested that environmental pollution from an earthquake might be associated with anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV).

AIM

To determine the incidence of AAV during the 3-year period before (period 1), and the 3 years following (period 2), the earthquake that occurred on 22 February 2011 in Christchurch, New Zealand.

METHODS

All ANCA tests performed in the Canterbury region for 3 years before the earthquake (period 1, 2007-2010), and for 3 years after the earthquake (period 2, 2011-2014) were examined. AAV was defined according to The European Medicines Agency classification algorithm. Medical records were reviewed and cases were included if they were newly diagnosed within the study period. Incidence was calculated using population data from the 2013 New Zealand census.

RESULTS

A total of 52 new cases of AAV was identified. The incidence in period 1 was 1.87/100 000/annum (95% C.I. 1.23-2.72), and for period 2 was 1.73/100 000/annum (95% C.I. 1.12-2.55). There was no statistically significant difference in incidence between the two study periods. There was no difference when analysing by myeloperoxidase (MPO) or proteinase-3 status, or restricting the analyses to those residing in an urban environment. The mean age at diagnosis for MPO AAV was significantly younger in period 2 than period 1 (61 years vs 71 years, P = 0.05). There were no other clinically important differences between the two groups.

CONCLUSION

This study does not support the hypothesis that an environmental agent, caused by dust pollution related to earthquake damage, has a causative role in the pathogenesis of AAV.

Pathophysiology of ANCA-associated Vasculitis

Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis is characterized as inflammation of small-sized to medium-sized blood vessels and encompasses several clinicopathologic entities including granulomatosis with polyangiitis, microscopic polyangiitis, eosinophilic granulomatosis with polyangiitis, and renal-limited ANCA-associated vasculitis. Over the past several decades, significant progress has been made in understanding the pathophysiology of ANCA-associated vasculitis. Although neutrophils contain a multitude of granular proteins, clinically significant autoantibodies are only recognized against myeloperoxidase and proteinase 3, both of which are present in the azurophilic granules. The propensity to develop these antibodies depends on a variety of predisposing factors such as microbial infection, genetic factors, environmental agents, and therapeutic drugs among others. These factors are usually associated with production of proinflammatory cytokines with capacity to prime the neutrophils. As a result a high proportion of neutrophils in circulation may be primed resulting in exposure of cytoplasmic proteins including myeloperoxidase and proteinase 3 on the surface of the neutrophils. Primed neutrophils are activated by interaction with ANCA in circulation. Activated neutrophils attach to and transmigrate through endothelium and accumulate within the vessel wall. These neutrophils degranulate and produce reactive oxygen radicals and ultimately die, causing tissue injury. Endothelial injury results in leakage of serum proteins and coagulation factors causing fibrinoid necrosis. B cells produce ANCAs, as well as neutrophil abnormalities and imbalances in different T-cell subtypes with excess of Th17, which perpetuate the inflammatory process.

Silicosis, then microscopic polyangiitis-antineutrophil cytoplasmic antibodies-associated vasculitis may be work-related disease in patients with silicosis

A 74-year-old man with silicosis was admitted to the hospital because of prolonged fever. After referral to internal medicine for persistent fever and renal dysfunction, workup revealed antineutrophil cytoplasmic antibodies (ANCA) positivity. He was diagnosed with microscopic polyangiitis (MPA). After treatment with immunosuppressive therapy, his condition improved. Herein, we discuss silica exposure and the risk of ANCA-associated vasculitis (AAV), particularly in terms of work-related diseases. Silica exposure is a notorious risk factor for developing AAV, which is potentially lethal when not identified. When we see a silicosis patient with new-onset prolonged fever and generalized fatigue, AAV should be taken into consideration. This case report provides beneficial information to reliably assess patients at high risk of developing AAV in primary care settings.

Occupational exposure to respirable crystalline silica and chronic non-malignant renal disease: systematic review and meta-analysis

Background

While occupational exposure to respirable silica is known to lead to lung disease, most notably silicosis, its association with chronic kidney disease is unclear.

Objectives

This review explores the association between occupational exposure to respirable silica and chronic non-malignant renal disease such as glomerulonephritis. The evidence has been collected and compiled. Possible sources of bias are thoroughly discussed.

Methods

Cohort studies with silica exposure and case–control studies of renal disease were searched in PubMed until January 2015. Two authors independently abstracted data; any disagreement was resolved by consulting a third reviewer. A meta-analysis was performed to evaluate the association to silica exposure.

Results

A total of 23 cohort and four case–control studies were included in the analysis. The meta-analysis of cohort studies yielded elevated overall SMRs for renal disease. Some studies, however, included dose–response analyses, most of which did not show a positive trend. The approaches and results of the case–control studies were very heterogeneous.

Conclusions

While the studies of cohorts exposed to silica found elevated SMRs for renal disease, no clear evidence of a dose–response relationship emerged. The elevated risk may be attributed to diagnostic and methodological issues. In order to permit a reliable estimation of a possible causal link, exposed cohorts should be monitored for renal disease, as the information from mortality studies is hardly reliable in this field.

Electronic supplementary material

The online version of this article (doi:10.1007/s00420-017-1219-x) contains supplementary material, which is available to authorized users.

Rheumatic diseases induced by drugs and environmental factors: the state-of-the-art - part two

The majority of rheumatic diseases belong to the group of autoimmune diseases and are associated with autoantibody production. Their etiology is not fully understood. Certain medications and environmental factors may have an influence on the occurrence of rheumatic diseases. Establishing a cause-effect relationship between a certain factor and disease induction is not always simple. It is important to administer the drug continuously or monitor exposure to a given factor in the period preceding the onset of symptoms. The lack of early diagnosed autoimmune disease, or finally the lack of symptoms within a few weeks/months after discontinuation of the drug/cessation of exposure, is also important.

The most frequently mentioned rheumatic diseases caused by drugs and environmental factors include systemic lupus erythematosus (SLE), scleroderma, systemic vasculitis, polymyositis, dermatomyositis, and Sjögren’s syndrome.

The objective of this study is to summarize current knowledge on rheumatic diseases induced by drugs and environmental factors.

Micro and nanoparticles as possible pathogenetic co-factors in mixed cryoglobulinemia

BACKGROUND

Mixed cryoglobulinemia (MC) is a rare multisystem disease whose aetiopathogenesis is not completely understood. Hepatitis C virus (HCV) infection may have a causative role, and genetic and/or environmental factors may also contribute.

AIMS

To investigate the presence and possible role of environmental agents in MC.

METHODS

We recruited 30 HCV-infected MC patients with different clinical manifestations and a control group of 30 healthy, sex-/age-matched volunteers. We collected serum samples from each patient and incubated at 4°C for 7 days to obtain cryoprecipitate samples. We used environmental scanning electron microscopy (ESEM) and energy dispersive X-ray spectroscopy microanalysis to verify the presence of microparticles (MPs) and nanoparticles (NPs) in serum and cryoprecipitate samples. We evaluated environmental exposure using a medical and occupational history questionnaire for each subject.

RESULTS

MC patients had a significantly higher risk of occupational exposure (OR 5.6; 95% CI 1.84-17.50) than controls. ESEM evaluation revealed a significantly higher concentration, expressed as number of positive spots (NS), of serum inorganic particles in MC patients compared with controls (mean NS 18, SD = 16 versus NS 5.4, SD = 5.1; P < 0.05). Cryoprecipitate samples of MC patients showed high concentrations of inorganic particles (mean NS 49, SD = 19). We found a strong correlation between NS and cryocrit (i.e. percentage of cryoprecipitate/total serum after centrifugation at 4°C) levels (P < 0.001).

CONCLUSIONS

In addition to HCV infection, MPs and NPs might play an important role in the aetiopathogenesis of MC.

Silica-Triggered Autoimmunity in Lupus-Prone Mice Blocked by Docosahexaenoic Acid Consumption

Occupational exposure to respirable crystalline silica (cSiO2, quartz) is etiologically linked to systemic lupus erythematosus (lupus) and other human autoimmune diseases (ADs). In the female NZBWF1 mouse, a widely used animal model that is genetically prone to lupus, short-term repeated intranasal exposure to cSiO2 triggers premature initiation of autoimmune responses in the lungs and kidneys. In contrast to cSiO2's triggering action, consumption of the ω-3 polyunsaturated fatty acid docosahexaenoic acid (DHA) prevents spontaneous onset of autoimmunity in this mouse strain. The aim of this study was to test the hypothesis that consumption of DHA will prevent cSiO2-triggered autoimmunity in the female NZBWF1 mouse. Mice (6 wk old) were fed isocaloric AIN-93G diets containing 0.0, 0.4, 1.2 or 2.4% DHA. Two wk after initiating feeding, mice were intranasally instilled with 1 mg cSiO2 once per wk for 4 wk and maintained on experimental diets for an additional 12 wk. Mice were then sacrificed and the lung, blood and kidney assessed for markers of inflammation and autoimmunity. DHA was incorporated into lung, red blood cells and kidney from diet in a concentration-dependent fashion. Dietary DHA dose-dependently suppressed cSiO2-triggered perivascular leukocyte infiltration and ectopic lymphoid tissue neogenesis in the lung. DHA consumption concurrently inhibited cSiO2-driven elevation of proinflammatory cytokines, B-cell proliferation factors, IgG and anti-dsDNA Ig in both bronchoalveolar lavage fluid and plasma. DHA's prophylactic effects were further mirrored in reduced proteinuria and glomerulonephritis in cSiO2-treated mice. Taken together, these results reveal that DHA consumption suppresses cSiO2 triggering of autoimmunity in female NZBWF1 mice as manifested in the lung, blood and kidney. Our findings provide novel insight into how dietary modulation of the lipidome might be used to prevent or delay triggering of AD by cSiO2. Such knowledge opens the possibility of developing practical, low-cost preventative strategies to reduce the risk of initiating AD and subsequent flaring in cSiO2-exposed individuals. Additional research in this model is required to establish the mechanisms by which DHA suppresses cSiO2-induced autoimmunity and to ascertain unique lipidome signatures predictive of susceptibility to cSiO2-triggered AD.

An update on dietary phenolic compounds in the prevention and management of rheumatoid arthritis

Certain nutritional components influence the cellular metabolism and interfere in the pathological inflammatory process, so that they may act as a coadjuvant in the treatment of many chronic inflammatory diseases, including rheumatoid arthritis (RA).

Two Cases of Tsunami Dust Pneumonia: Organizing Pneumonia Caused by the Inhalation of Dried Tsunami Sludge after the 2011 Great East Japan Earthquake

We report two cases of organizing pneumonia (OP) secondary to the inhalation of the dried tsunami sludge which formed during the 2011 Great East Japan Earthquake and the consequent tsunami. After the disaster, both of these patients had been engaged in the restoration work. About half a month later, they developed shortness of breath and pulmonary infiltrates. These patients were diagnosed with interstitial pneumonia. Their biopsy specimens revealed multifocal peribronchiolitis and OP. An electron probe microanalysis of these specimens demonstrated the presence of elements from the earth's crust in the inflammatory lesions. These two cases indicate that exposure to dried tsunami sludge can cause OP.

Association between environmental exposures and granulomatosis with polyangiitis in Canterbury, New Zealand

Introduction

Granulomatosis with polyangiitis (GPA) is a rare systemic vasculitis. While aetiology is unknown the prominent respiratory involvement suggests inhaled antigens may be involved. The aim of this study was to identify environmental risk factors associated with GPA in Canterbury, New Zealand.

Methods

A case-controlled study was undertaken. All GPA cases fulfilled American College of Rheumatology (ACR), Chapel Hill Consensus Criteria (CHCC) or the European Medicines Agency (EMA) criteria. Each case was gender matched with four controls - 2 musculoskeletal (osteoarthritis or fracture) and 2 respiratory (asthma or chronic obstructive pulmonary disease). One musculoskeletal control and one respiratory control were age matched with the case at the time of the interview (interview) and the remaining two controls were age matched at the time their case experienced the first symptom of vasculitis (index). A structured questionnaire to assess potential environmental agents was administered without blinding for case/control status. Data were analyzed using conditional logistic regression to allow for the individual matching of cases and controls to assess for association between environmental factors and GPA.

Results

49 cases and 196 controls were recruited. 53 % were male and the mean ± standard deviation (SD) age of the cases was 64.9 ± 12.4 years, interview controls 65.1 ± 12.4.years and index controls 53.9 ± 14.5 years. Any reported exposure to dust (specifically silica and grain dust) was associated with GPA, odds ratio (OR) 3.6 (95 % confidence interval (CI); 1.5–8.3, p = 0.003). Occupation as a farm worker was associated with GPA OR 3.43 (1.5–7.5, p = 0.002). Specific gardening activities were associated with GPA including digging (OR 3.2; 1.4–7.0; p = 0.003), mowing (OR 2.7; 1.3–5.8; p = 0.008) and planting (OR 2.6; 1.2–5.5; p = 0.013).

Conclusion

We have replicated findings from northern hemisphere studies identifying dust exposure as well as farm exposure as risk factors for the development of GPA. We have shown activities associated with exposure to inhaled antigens, in particular those related to farming or gardening activities may increase the risk of GPA.

The pathologist's view of silicosis in 1930 and in 2015. The Johannesburg Conference legacy

The 1930 International Labour Office Conference on silicosis in Johannesburg was a turning point in the history of silicosis and in the recognition of the associated pathologic patterns. Since 1930, pneumoconioses such as silicosis have become much rarer in developed countries and can now be diagnosed at an early stage based on clinical and radiologic criteria. However, in spite of these advances, pathologists must remember to look for silica in tissues, particularly when clinical and radiologic findings are more uncertain. Furthermore, nowadays pathologists essentially observe silicotic lesions as incidental findings adjacent to lung cancers. In addition to identifying the characteristic lesions, pathologists must also try to identify their causative agent, in the case of crystalline silica firstly by using polarized light examination, followed as appropriate by more sophisticated devices. Finally, pathologists and clinicians must always keep in mind the various implications of exposure to silica compounds in a wide range of diseases.

Enhancement of regulatory T cell-like suppressive function in MT-2 by long-term and low-dose exposure to asbestos

Asbestos exposure causes lung fibrosis and various malignant tumors such as lung cancer and malignant mesothelioma. The effects of asbestos on immune cells have not been thoroughly investigated, although our previous reports showed that asbestos exposure reduced anti-tumor immunity. The effects of continuous exposure of regulatory T cells (Treg) to asbestos were examined using the HTLV-1 immortalized human T cell line MT-2, which possesses a suppressive function and expresses the Treg marker protein, Foxp3. Sublines were generated by the continuous exposure to low doses of asbestos fibers for more than one year. The sublines exposed to asbestos showed enhanced suppressive Treg function via cell-cell contact, and increased production of soluble factors such as IL-10 and transforming growth factor (TGF)-β1. These results also indicated that asbestos exposure induced the reduction of anti-tumor immunity, and efforts to develop substances to reverse this reduction may be helpful in preventing the occurrence of asbestos-induced tumors.

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.

Microscopic polyangiitis associated with pleuropericarditis, pulmonary embolism and pulmonary hemorrhage as a complication of silicosis

Silica (silicon dioxide) occupational exposure has been linked to both pulmonary and extra-pulmonary toxicity. Silicosis is the major pulmonary toxicity, which has also been associated with the development of collagen-vascular disease and with anti-neutrophil cytoplasmic antibody (ANCA)-positive vasculitis, especially perinuclear anti-neutrophil cytoplasmic antibodies (P-ANCA). The most common pulmonary manifestations of microscopic polyangitis (MPA) are interstitial fibrosis and alveolar hemorrhage. We describe a patient who had unusual presentation of microscopic polyangitis, characterized by lung hemorrhage, rapidly progressive glomerulonephritis, pleuropericarditis and pulmonary embolism that was associated with a history of silica exposure and radiologic evidence for silicosis.

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.

Nested case-control study of selected systemic autoimmune diseases in World Trade Center rescue/recovery workers

OBJECTIVE

To test the a priori hypothesis that acute and chronic work exposures to the World Trade Center (WTC) site on or after September 11, 2001 were associated with risk of new-onset systemic autoimmune diseases.

METHODS

A nested case-control study was performed in WTC rescue/recovery workers who had received a rheumatologist-confirmed systemic autoimmune disease diagnosis between September 12, 2001 and September 11, 2013 (n = 59), each of whom was individually matched to 4 randomly selected controls (n = 236) on the basis of year of hire (±1 year), sex, race, and work assignment (firefighter or emergency medical service). Acute exposure was defined according to the earliest time of arrival (morning of 9/11 versus later) at the WTC site, and chronic exposure was defined as duration (number of months) of WTC site-related work. Rheumatologists were blinded with regard to each subject's exposure status. The conditional odds ratios (CORs) with 95% confidence intervals (95% CIs) for incident autoimmune disease were derived from exact conditional logistic regression models.

RESULTS

Rheumatoid arthritis was the most common autoimmune diagnosis (37% of subjects), followed by spondyloarthritis (22%), inflammatory myositis (14%), systemic lupus erythematosus (12%), systemic sclerosis (5%), Sjögren's syndrome (5%), antiphospholipid syndrome (3%), and granulomatosis with polyangiitis (Wegener's) (2%). The COR for incident autoimmune disease increased by 13% (COR 1.13, 95% CI 1.02-1.26) for each additional month worked at the WTC site. These odds were independent of the association between high acute exposure (working during the morning of 9/11) and disease outcome, which conveyed an elevated, but not statistically significant, risk (COR 1.85, 95% CI 0.86-3.89).

CONCLUSION

Prolonged work at the WTC site, independent of acute exposure, was an important predictor of post-9/11 systemic autoimmune diseases. The WTC Health Program should expand surveillance efforts for those with extended exposures, as early detection can facilitate early treatment, which has been shown to minimize organ damage and improve quality of life.

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.

Eosinophilic granulomatosis with polyangiitis: an overview

Eosinophilic granulomatosis with polyangiitis (EGPA) is a multisystemic disorder, belonging to the small vessel anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis, defined as an eosinophil-rich and necrotizing granulomatous inflammation often involving the respiratory tract, and necrotizing vasculitis predominantly affecting small to medium-sized vessels, associated with asthma and eosinophilia. EGPA pathogenesis is not well known: HLA-DRB1*04 and *07, HLA-DRB4 and IL10.2 haplotype of the IL-10 promoter gene are the most studied genetic determinants. Among the acquired pathogenetic factors, the exposure to different allergens, infections, vaccinations, drugs, and silica exposure have been involved. Eosinophils are the most characteristic cells in EGPA and different studies have demonstrated their role as effector and immunoregulatory cells. EGPA is considered as a disease with a prevalent activation of the Th-2 cellular-mediated inflammatory response and also humoral immunity plays an important role. A link between B and T inflammatory responses may explain different disease features. EGPA typically develops into three sequential phases: the allergic phase, distinguished by the occurrence of asthma, allergic rhinitis, and sinusitis, the eosinophilic phase, in which the main pathological finding is the eosinophilic organ infiltrations (e.g., lungs, heart, and gastrointestinal system), and the vasculitic phase, characterized by purpura, peripheral neuropathy, and constitutional symptoms. ANCA (especially pANCA anti-myeloperoxidase) are present in 40-60% of the patients. An elevation of IgG4 is frequently found. Corticosteroids and cyclophosphamide are classically used for remission induction, while azathioprine and methotrexate are the therapeutic options for remission maintenance. B-cell depletion with rituximab has shown promising results for remission induction.

Silicosis: geographic changes in research: an analysis employing density-equalizing mapping

BACKGROUND

A critical evaluation of scientific efforts is needed in times of modified evaluation criteria for academic personnel and institutions.

METHODS

Using scientometric benchmark procedures and density-equalizing mapping, we analysed the global scientific efforts on "silicosis" of the last 92 years focusing on geographical changes within the last 30 years, specifying the most productive authors, institutions, countries and the most successful cooperations.

RESULTS

The USA as the most productive supplier have established their position as center of international cooperation, followed in considerable distance by the United Kingdom, Germany and China. Asian countries, particularly China, catch up and are expected to excel the USA still in this decade.

CONCLUSION

The combination of scientometric procedures with density-equalizing mapping reveals a distinct global pattern of research productivity and citation activity. Modified h-index, citationrate and impact factor have to be discussed critically due to distortion by bias of self-citation, language and co-authorship.

Unmet needs in respiratory diseases : "You can't know where you are going until you know where you have been"--Anonymous

The care of patients with respiratory diseases has improved vastly in the past 50 years. In spite of that, there are still massive challenges that have not been resolved. Although the incidence of tuberculosis has decreased in the developed world, it is still a significant public health problem in the rest of the world. There are still over 2 million deaths annually from tuberculosis, with most of these occurring in the developing world. Even with the development of new pharmaceuticals to treat tuberculosis, there is no indication that the disease will be eradicated. Respiratory syncytial virus, severe acute respiratory syndrome, and pertussis are other respiratory infectious diseases with special problems of their own, from vaccine development to vaccine coverage. Asthma, one of the most common chronic diseases in children, still accounts for significant mortality and morbidity, as well as high health care costs worldwide. Even in developed countries such as the USA, there are over 4,000 deaths per year. Severe asthma presents a special problem, but the question is whether there can be one treatment pathway for all patients with severe asthma. Severe asthma is a heterogeneous disease with many phenotypes and endotypes. The gene for cystic fibrosis was discovered over 24 years ago. The promise of gene therapy as a cure for the disease has fizzled out, and while new antimicrobials and other pharmaceuticals promise improved longevity and better quality of life, the average life span of a patient with cystic fibrosis is still at about 35 years. What are the prospects for gene therapy in the twenty-first century? Autoimmune diseases of the lung pose a different set of challenges, including the development of biomarkers to diagnose and monitor the disease and biological modulators to treat the disease.

Prospective study to evaluate the association between systemic sclerosis and occupational exposure and review of the literature

INTRODUCTION

Systemic sclerosis (SSc) has complex pathogenesis and likely multifactorial causes. Environmental exposures have been suggested to play a role in SSc pathogenesis, including occupational exposure to pollutants and chemicals as well as use of drugs leading to modulation of immune response. Thus, this case-control study aimed to assess: the relationship between SSc and occupational exposure; and the risk of SSc related to occupational exposure in male and female patients.

METHODS

From 2005 to 2008, 100 patients with a definite diagnosis of SSc were included in the study; 3 age, gender, and smoking habits matched controls were selected for each patient. A committee of experts evaluated blindly occupational exposure to crystalline silica, white spirit, organic solvents, ketones, welding fumes, epoxy resins, and pesticides; an occupational exposure score was calculated for all subjects. Our findings were compared with previous data in the literature.

RESULTS

Increased ORs for SSc were found for: crystalline silica (p<0.0001), white spirit (p<0.0001), aromatic solvents (p=0.0002), chlorinated solvents (p=0.014), trichlorethylene (p=0.044), ketones (p=0.002) and welding fumes (p=0.021). Elevated risk associated with high final cumulative score in SSc was observed for: crystalline silica, white spirit, chlorinated solvents, trichlorethylene, aromatic solvents, any type of solvents, ketones and welding fumes. A marked association between SSc and occupational exposure was further found for: 1) crystalline silica, chlorinated solvents, trichloroethylene, white spirit, ketones and welding fumes in male patients; and 2) white spirit, aromatic solvents, any type of solvent and ketones in female patients. Finally, we did not find an association between SSc and: 1) the use of drugs that have been speculated to play a role in SSc onset (anorexigens, pentazocine, bromocriptine, l-tryptophan); 2) implants - that are prosthesis, silicone implants, and contact lenses; and 3) dyeing hair. In the literature, SSc has been associated with occupational exposure to silica and solvents, while the association between SSc and specific organic solvents and welding fumes has been anecdotally reported.

CONCLUSION

The following occupational factors have an impact in the development of SSc: crystalline silica, white spirit, aromatic solvents, chlorinated solvents, trichlorethylene, ketones and welding fumes. The risk of SSc appears to be markedly associated with high cumulative exposure. Finally, the association between SSc and occupational exposure may be variable according to gender.