The effect of cigarette smoking on the clinical and serological phenotypes of polymyositis and dermatomyositis

Idiopathic inflammatory myopathies related lung disease in adults

Interstitial lung disease (ILD) is common in idiopathic inflammatory myopathies in adults, especially in patients with antisynthetase syndrome and anti-MDA5 antibody-associated dermatomyositis. Pulmonary manifestations can range from subclinical ILD to rapidly progressive respiratory failure. Coexistent myositis, characteristic skin lesions, arthritis, and Raynaud's phenomenon are common. However, 16-65% of patients present with isolated lung disease. Detection of myositis-specific and myositis-associated antibodies can aid in diagnosis and disease characterisation. Chest imaging and pathology most commonly show non-specific interstitial pneumonia and organising pneumonia patterns. Immunosuppression is the mainstay of management with aggressive combination treatment for rapidly progressive disease and incremental escalation as needed for chronic ILD. The addition of antifibrotic agents is an option in progressive fibrotic disease, and lung transplantation can be considered in severe, end-stage disease. Most patients respond to treatment, but short-term mortality remains high for patients with rapidly progressive disease associated with anti-MDA5 antibody ILD.

The Impact of Tobacco Smoking on Systemic Sclerosis, Idiopathic Inflammatory Myositis, and Systemic Lupus Erythematosus

This narrative review aims specifically to explore the relationship between tobacco exposure and systemic sclerosis (SSc), idiopathic inflammatory myositis (IIM), and systemic lupus erythematosus (SLE). Relevant articles were obtained by searching key terms such as "tobacco," "smoking," "scleroderma," "myositis," "lupus," and "Sjögren's" in PubMed and Google Scholar databases. The selected articles ranged from the years 2010 to 2023. Inclusion criteria were based on the relevance and contribution to the field of study. Systemic sclerosis is a complex condition involving multiple immune cell lines that can be influenced by tobacco. However, the existing literature does not provide sufficient evidence to support an increased risk of SSc in smokers or the impact on treatment options. Cigarette smoking does increase the risk of skin ulcerations in SSc patients. In addition, cigarette smoking has been associated with IIM through genetic and molecular mechanisms. Smokers with dermatomyositis or polymyositis are at an elevated risk of atherosclerosis and interstitial lung disease. Similarly, smoking in patients with SLE increases the risk of organ damage, thrombosis, and disease severity compared with non-smokers. Smokers with SLE also have more difficulty in controlling disease flares compared with non-smokers. Tobacco exposure can lead to secondary complications in patients with IIM and SLE, although the course of treatment may not differ significantly. No definitive conclusions can be drawn to the clear relationship between tobacco smoking and Sjögren's's syndrome.

Effect of smoking on thrombotic antiphospholipid syndrome: a 10-year prospective cohort study

OBJECTIVES

Cigarette smoking is an established risk factor for autoimmune diseases. However, whether smoking plays a clear role in thrombotic APS (TAPS) has not been determined. We aimed to investigate the effects of smoking on the clinical characteristics and prognosis of TAPS.

METHODS

This was a prospective cohort study from 2013 to 2022. During the study period, 297 patients were diagnosed with TAPS, including 82 smokers and 215 non-smokers. After propensity score matching, 57 smokers and 57 non-smokers matched by age and sex were analysed.

RESULTS

Overall, smokers with TAPS had more cardiovascular risk factors than non-smokers, including hypertension (36.59% vs 14.42%, P < 0.001), obesity (15.85% vs 7.44%, P = 0.029), dyslipidaemia (64.63% vs 48.37%, P = 0.012) and hyperhomocysteinaemia (62.20% vs 36.28%, P < 0.001). Arterial thrombotic events were more common in smokers at diagnosis (62.20% vs 46.05%, P = 0.013), especially myocardial infarction, visceral thrombosis and peripheral vascular thrombosis. After matching, smokers showed balanced cardiovascular risk factors with non-smokers at baseline, but retained a higher prevalence of arterial thrombosis (59.65% vs 33.33%, P = 0.005), mainly distributed in cerebral vascular, cardiovascula and retinal vascular territories. During follow-up, smokers presented a tendency for more recurrent arterial thrombosis and less recurrent venous thrombosis. Smokers had significantly poorer outcomes for organ damage with higher Damage Index for APS score (median 2.00 vs 1.00, P = 0.008), especially in the cardiovascular (26.32% vs 3.51%, P = 0.001), gastrointestinal (15.79% vs 1.75%, P = 0.016) and ophthalmologic (10.53% vs 00.00%, P = 0.027) systems.

CONCLUSION

Smoking is related to increased arterial events and poor prognosis in TAPS patients. Patients with TAPS should be fully encouraged to avoid smoking.

Clinical Features and Immunogenetic Risk Factors Associated With Additional Autoantibodies in Anti-Transcriptional Intermediary Factor 1γ Juvenile-Onset Dermatomyositis

OBJECTIVE

Novel autoantibody specificities including anti-CCAR1 were recently discovered in adult patients with anti-transcriptional intermediary factor (TIF1)-positive dermatomyositis (DM) and were associated with attenuated cancer emergence. The aims of the present study were to examine whether these autoantibodies occur in patients with juvenile-onset DM (JDM) and to determine their associated features.

METHODS

Sera from 150 patients with anti-TIF1γ autoantibody-positive JDM in a cross-sectional cohort and 90 juvenile healthy controls were assayed for anti-CCAR1, anti-C1Z1, anti-IMMT, anti-TBL1XR1, and anti-Sp4 autoantibodies. Demographics, myositis autoantibodies, clinical features, medications, outcomes, and HLA-DRB1 and HLA-DQA1 alleles were compared between those with and without these autoantibodies.

RESULTS

Any one of the anti-TIF1γ-associated autoantibodies was present in 44 patients (29%) overall, including 25 (17%) with anti-Sp4, 22 (15%) with anti-TBL1XR1, 14 (9%) with anti-CCAR1, 2 (1%) with anti-C1Z1, and 2 (1%) with anti-IMMT autoantibodies. These anti-TIF1γ-associated autoantibodies frequently co-occurred. Patients with any of the anti-TIF1γ-associated autoantibodies had less frequent falling (34% [15] vs. 53% [56], P = 0.032) and lower peak muscle enzymes. None of the patients had cancer. Among White patients, HLA-DRB1*03 was protective against an anti-TIF1γ-associated autoantibody (odds ratio 0.20, 95% confidence interval 0.07-0.52).

CONCLUSION

Autoantibodies associated with anti-TIF1γ were found in isolation and in combination among a subset of patients with JDM. Patients with these autoantibodies had less severe muscle disease and were not enriched for HLA-DRB1*03. Additional autoantibodies among patients with positive anti-TIF1γ with JDM likely contribute to the heterogeneity of the anti-TIF1γ serologic subgroup.

Extracellular Vesicles in the Pathogenesis, Clinical Characterization, and Management of Dermatomyositis: A Narrative Review

Extracellular vesicles (EVs) are lipid-bilayer particles secreted from cells that primarily assist in cell-to-cell communication through the content of their cargo, such as proteins and RNA. EVs have been implicated in the pathogenesis of various autoimmune diseases, including dermatomyositis (DM), an inflammatory autoimmune disease characterized by distinct cutaneous manifestations, myopathy, and lung disease. We sought to review the role of EVs in DM and understand how they contribute to the pathogenesis and clinical characterization of the disease. We summarized the research progress on EVs in dermatomyositis based on recent publications. EV cargoes, such as double-stranded DNA, microRNA, and proteins, contribute to DM pathogenesis and mediate the proinflammatory response and cytokine release through signaling pathways such as the stimulator of interferon genes (STING) pathway. These nucleic acids and proteins have been proposed as disease-specific, stable biomarkers to monitor disease activity and responses to therapy. They also correlate with clinical parameters, inflammatory markers, and disease severity scores. Furthermore, some markers show an association with morbidities of DM, such as muscle weakness and interstitial lung disease. The continued study of EVs will help us to further elucidate our understanding of dermatomyositis.

The Role of Environmental Factors in the Development of Idiopathic Inflammatory Myopathies: a Narrative Review

PURPOSE OF REVIEW

This review aims to evaluate recent findings on the role of environmental factors in the development and clinical presentation of idiopathic inflammatory myopathies (IIMs).

RECENT FINDINGS

A targeted literature review was conducted to identify reports relevant to the association between environmental factors and IIMs published over the past three years. There has been an increasing number of publications dealing with the association of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection or vaccination with the development of IIMs, highlighting the significant role of the antiviral immune response in the pathogenesis of the disease. Traditional environmental factors associated with the pathogenic process of IIM subclassifications included drugs such as statins and immune checkpoint inhibitors, ultraviolet radiation, smoking, air pollutants, and vitamin D deficiency. Correlations of seasonality and residence with the onset of certain IIM subtypes suggest a potential role of environmental triggers in the pathogenic process. An interplay between genetic predisposition and various environmental factors might contribute to the development of IIMs as well as the heterogeneous clinical and serological presentation of IIMs. The growing evidence on the role of environmental factors in the development of IIMs provides important clues to elucidate the pathophysiology of these disease entities. The mechanisms underlying the interactions between genetic predisposition and environmental factors should be investigated in the future.

Epidemiology of the idiopathic inflammatory myopathies

The idiopathic inflammatory myopathies (IIMs) are a heterogeneous group of systemic autoimmune diseases that affect the skeletal muscles and can also involve the skin, joints, lungs and heart. The epidemiology of IIM is obscured by changing classification criteria and the inherent shortcomings of case identification using healthcare record diagnostic coding. The incidence of IIM is estimated to range from 0.2 to 2 per 100,000 person-years, with prevalence from 2 to 25 per 100,000 people. Although the effects of age and gender on incidence are known, there is only sparse understanding of ethnic differences, particularly in indigenous populations. The incidence of IIM has reportedly increased in the twenty-first century, but whether this is a genuine increase is not yet known. Understanding of the genetic risk factors for different IIM subtypes has advanced considerably. Infections, medications, malignancy and geography are also commonly identified risk factors. Potentially, the COVID-19 pandemic has altered IIM incidence, although evidence of this occurrence is limited to case reports and small case series. Consideration of the current understanding of the epidemiology of IIM can highlight important areas of interest for future research into these rare diseases.

Environmental exposures as risk factors for idiopathic inflammatory myopathies

Idiopathic inflammatory myopathies (IIM) are a heterogeneous group of rare autoimmune diseases, with increasing incidence rates observed in the recent years. The pathogenesis of IIM remains not fully understood, and the interaction of genetic and environmental factors is suspected. It is unclear whether the observed upward trend in the IIM incidence is solely due to improved access to effective diagnostics or perhaps due to increased exposure to external risk factors. The PUBMED database was thoroughly searched for articles describing environmental exposures potentially triggering the onset of IIM. The article summarizes the current knowledge available on this subject, taking into account various environmental factors, including among others UV radiation, infectious agents with SARS-CoV-2, inhaled particles, or iatrogenic effects. Limitations and unmet needs requiring further studies were highlighted.

Assessment of cardiovascular risk factors in patients with idiopathic inflammatory myopathies: a systematic review

We performed a systematic review of cardiovascular risk factors in idiopathic inflammatory myopathies (IIMs) and their cardiovascular outcomes, including acute coronary syndrome and stroke. A qualitative systematic review was conducted from January 1956 to December 2022 according to the PRISMA protocol using three electronic databases: PubMed, Web of Science, and Scopus. The studies were analyzed based on the following eligibility criteria: at least one combination of the terms described in the search strategy appeared in the title, written in English, Portuguese, or Spanish, and addressed risk factors for cardiovascular diseases in IIMs. Brief reports, reviews, papers addressing juvenile IIMs, congress proceedings, monographs, and dissertations were excluded. Twenty articles were included. According to the literature, most patients with IIMs are middle-aged North American or Asian women, with dyslipidemia and hypertension. The prevalence of the cardiovascular risk factors was generally low in IIMs, but with a high incidence of acute myocardial infarction. Further theoretical and prospective studies are needed to define the actual impact of each variable (e.g., hypertension, diabetes, smoking, alcoholism, obesity, and dyslipidemia) on the cardiovascular risk of patients with IIMs.

Autoantibodies Recognizing Specificity Protein 4 Co-occur With Anti-Transcription Intermediary Factor 1 and Are Associated With Distinct Clinical Features and Immunogenetic Risk Factors in Juvenile Myositis

OBJECTIVE

Autoantibodies recognizing specificity protein 4 (Sp4) were recently discovered in adults with idiopathic inflammatory myopathies (IIM). Anti-Sp4 autoantibodies co-occurred in patients with anti-transcription intermediary factor 1 (anti-TIF1) autoantibody-positive dermatomyositis (DM) and were associated with a reduced risk of cancer. In the present study, the prevalence and clinical features associated with anti-Sp4 autoantibodies in juvenile-onset IIM were investigated.

METHODS

Serum samples from 336 patients with juvenile myositis in a cross-sectional cohort and 91 healthy controls were screened for anti-Sp4 autoantibodies using enzyme-linked immunosorbent assay. Clinical characteristics, outcomes, and HLA alleles of those with and those without anti-Sp4 autoantibodies were compared.

RESULTS

Anti-Sp4 autoantibodies were present in 23 patients (7%) with juvenile myositis and were not present in any of the controls. Anti-Sp4 autoantibodies were found among each clinical myositis subgroup. The frequency of TIF1 autoantibody positivity was significantly higher among those with anti-Sp4 autoantibodies (21 [91%] versus 92 [30%], P < 0.001). In the anti-TIF1 autoantibody-positive subgroup, Raynaud's phenomenon (8 [38%] versus 2 [2%], P < 0.001) was more common and peak aspartate aminotransferase was significantly lower in those with anti-Sp4 autoantibodies. None of the patients with anti-Sp4 autoantibodies required a wheelchair. Among White patients, DQA1*04 and DRB1*08 were associated with anti-Sp4 autoantibodies.

CONCLUSION

Anti-Sp4 autoantibodies were found in patients with juvenile-onset IIM, predominantly those with coexisting anti-TIF1 autoantibodies. Patients with anti-Sp4 autoantibodies represent a phenotypic subset of anti-TIF1 autoantibody-positive myositis characterized by frequent Raynaud's phenomenon and less pronounced muscle involvement, similar to adults with these autoantibodies. Novel immunogenetic risk factors for White patients with IIM were identified among juveniles with anti-Sp4 autoantibodies.

Anti-synthetase syndrome masquerading as recurrent pneumonia

Anti-synthetase syndrome (ASS) is a rare inflammatory myopathy with a wide variety of clinical presentations. ASS-related interstitial lung disease (ASS-ILD) presents with rapid onset and progression, which could often be confused with other more common acute processes such as pneumonia, especially when ILD can be the sole manifestation. A woman in her 50s presented with recurrent dyspnoea for 2 months requiring multiple hospital admissions, and each time, she was diagnosed with multifocal pneumonia and treated with antibiotics. On admission, the evaluation revealed a markedly elevated creatine kinase level at 3258 U/L and a CT scan of the chest revealed worsening scattered ground-glass opacities. Given the concern for ILD as the cause of antibiotic failure, she underwent bronchoscopy with bronchoalveolar lavage which revealed non-specific interstitial pneumonia. A subsequent myositis panel revealed a positive anti-Jo-1 antibody, and she was diagnosed with ASS-ILD. She completed a course of intravenous immunoglobulin and methylprednisolone and experienced significant clinical improvement with the resolution of hypoxaemia and improved polyarthralgia.ASS could often be misdiagnosed as other more common acute lung processes, as a clinically subtle course can escape detection given its rarity, as well as its non-specific and highly variable presentations. This case highlights the importance of early suspicion and consideration of performing specific autoantibody testing when evaluating patients with a suspicion of undifferentiated autoimmune condition.

Skin disorders and interstitial lung disease: Part II-The spectrum of cutaneous diseases with lung disease association

Part 2 of this 2-part CME introduces dermatologists to noninfectious inflammatory skin diseases associated with pulmonary involvement. In many cases, dermatologists may be the first physicians recognizing respiratory complications associated with these diagnoses. Because pulmonary involvement is often the leading cause of morbidity and mortality, dermatologists should be comfortable screening and monitoring for lung disease in high-risk patients, recognizing cutaneous stigmata of lung disease in these patients and referring to pulmonary specialists, when appropriate, for prompt treatment initiation. Some treatments used for skin disease may not be appropriate in the context of lung disease and hence, choosing a holistic approach is important. Interstitial lung disease and pulmonary hypertension are the most common pulmonary complications and a significant cause of mortality in autoimmune connective tissue diseases, especially systemic sclerosis, dermatomyositis, and mixed connective tissue disease. Pulmonary complications, notably interstitial lung disease, are also common and life-threatening in sarcoidosis and vasculitis, while they are variable in neutrophilic and autoimmune blistering diseases.

Environmental Risks for Inflammatory Myopathies

This is an up-to-date review on external environmental factors for adult-onset idiopathic inflammatory myopathies (IIMs). Environmental factors with suggestive evidence including ultraviolet radiation, smoking, infectious agents (viruses in particular), pollutants, medications (ie, statin) and vitamin D deficiency are discussed. We also discuss the potential implications of environmental factors in IIM development, identify current challenges, and provide insight into future investigations.

Anti-FHL1 autoantibodies in juvenile myositis are associated with anti-Ro52 autoantibodies but not with severe disease features

OBJECTIVES

Four-and-a-half LIM domains 1 (FHL1) is a muscle-specific protein. Autoantibodies against FHL1 were recently discovered in adults with idiopathic inflammatory myopathies (IIMs) and were found to be associated with clinical features and outcomes indicative of increased disease severity. Anti-FHL1 autoantibodies have not been described in children. Here, the prevalence and clinical features associated with anti-FHL1 autoantibodies were examined in a large North American cohort of juvenile patients with IIM.

METHODS

Sera from 338 juvenile IIM patients and 91 juvenile healthy controls were screened for anti-FHL1 autoantibodies by ELISA. Clinical characteristics and HLA alleles of those with and without anti-FHL1 autoantibodies were compared among those with juvenile IIM.

RESULTS

Anti-FHL1 autoantibodies were present in 10.9% of juvenile IIM patients and 1.1% of controls. The frequency of anti-FHL1 autoantibodies among clinical and serologic subgroups did not differ. A higher percentage of Asian patients had anti-FHL1 autoantibodies (11% vs 0.7%; P = 0.002). Myositis-associated autoantibodies (MAAs) [odds ratio (OR) 2.09 (CI 1.03, 4.32)], anti-Ro52 autoantibodies specifically [OR 4.17 (CI 1.83, 9.37)] and V-sign rash [OR 2.59 (CI 1.22, 5.40)] were associated with anti-FHL1 autoantibodies. There were no differences in other features or markers of disease severity. No HLA associations with anti-FHL1 autoantibodies in Caucasian myositis patients were identified.

CONCLUSION

Anti-FHL1 autoantibodies are present in ∼11% of juvenile IIM patients and commonly co-occur with MAAs, including anti-Ro52 autoantibodies. In contrast to adult IIM, anti-FHL1 autoantibodies in juvenile myositis are associated with V-sign rash but not with other distinctive clinical features or worse outcomes.

The Genetics of Autoimmune Myositis

The idiopathic inflammatory myopathies (IIM) are rare, heterogeneous systemic autoimmune disorders, characterized by inflammation of skeletal muscle and multi-organ involvement. Studies to identify genetic risk factors and dysregulated gene expression in IIM aim to increase our understanding of disease pathogenesis. Genome-wide association studies have confirmed the HLA region as the most strongly associated region in IIM, with different associations between clinically-defined subgroups. Associated genes are involved in both the innate and adaptive immune response, while identification of variants reported in other autoimmune disorders suggests shared biological pathways. Targeted imputation analysis has identified key associated amino acid residues within HLA molecules that may influence antigen recognition. These amino acids increase risk for specific clinical phenotypes and autoantibody subgroups, and suggest that serology-defined subgroups may be more homogeneous. Recent data support the contribution of rare genetic variation to disease susceptibility in IIM, including mitochondrial DNA variation in sporadic inclusion body myositis and somatic mutations and loss of heterozygosity in cancer-associated myositis. Gene expression studies in skeletal muscle, blood and skin from individuals with IIM has confirmed the role of interferon signalling and other dysregulated pathways, and identified cell-type specific signatures. These dysregulated genes differentiate IIM subgroups and identify potential biomarkers. Here, we review recent genetic studies in IIM, and how these inform our understanding of disease pathogenesis and provide mechanistic insights into biological pathways.

The Geospatial Distribution of Myositis and Its Phenotypes in the United States and Associations With Roadways: Findings From a National Myositis Patient Registry

Background

Little is known about the spatial distribution of idiopathic inflammatory myopathies (IIM) in the United States (U.S.), or their geospatial associations.

Methods

We studied a national myositis patient registry, with cases diagnosed in the contiguous U.S. from 1985–2011 and comprised of dermatomyositis (DM, n = 484), polymyositis (PM, n = 358), and inclusion body myositis (IBM, n = 318) patients. To assess the association of myositis prevalence with distance from roads, we employed log-Gaussian Cox process models, offset with population density.

Results

The U.S. IIM case distribution demonstrated a higher concentration in the Northest. DM, IBM, and cases with lung disease were more common in the East, whereas PM cases were more common in the Southeast. One area in the West and one area in the South had a significant excess in cases of DM relative to PM and of cases with lung disease relative to those without lung disease, respectively. IIM cases tended to cluster, with between-points interactions more intense in the Northeast and less in the South. There was a trend of a higher prevalence of IIM and its major phenotypes among people living within 50 m of a roadway relative to living beyond 200 m. Demographic characteristics, rural-urban commuting area, and female percentage were significantly associated with the prevalence of IIM and with major phenotypes.

Conclusions

Using a large U.S. database to evaluate the spatial distribution of IIM and its phenotypes, this study suggests clustering in some regions of the U.S. and a possible association of proximity to roadways.

Recent advances in the diagnosis and management of interstitial pneumonia with autoimmune features: the perspective of rheumatologists

Interstitial pneumonia with autoimmune feature (IPAF) is a recently established disease entity that is comprised of interstitial lung diseases with evidence of autoimmune features but that does not fulfill the criteria for definite autoimmune rheumatic diseases. The classification criteria for IPAF were defined by the European Respiratory Society and American Thoracic Society in 2015. However, further studies to establish IPAF subgroups and treatment modalities for each subgroup are still needed. In this review, we discuss recent advances regarding IPAF and raise critical points for the diagnosis and management of patients with IPAF from the perspective of rheumatologists.

Comparison of relapsing polychondritis patients with and without central nervous system involvement: A retrospective study of 181 patients

The relapsing polychondritis (RP) patients with central nervous system (CNS) involvement were rare. We aimed to determine the clinical characteristics of RP patients with CNS involvement. The clinical data of 181 RP patients, hospitalized at Peking Union Medical College Hospital between December 2005 and February 2019, were collected. The patients were categorized into two subgroups: 25 RP patients with CNS involvement, and 156 RP patients without CNS involvement. The involvement of the ear was more frequent in RP patients with CNS involvement, compared with those of RP patients without CNS involvement (P < 0.01). After controlling sex and the admission age, logistic regression analysis revealed hypertension (odds ratio = 4.308, P = 0.006) and involvement of eye (odds ratio = 5.158, P = 0.001) and heart (odds ratio = 3.216, P = 0.025) were correlated with RP patients with CNS involvement, respectively. In addition, pulmonary infection (odds ratio = 0.170, P = 0.020), tracheal involvement (odds ratio = 0.073, P < 0.01), and involvement of laryngeal (odds ratio = 0.034, P = 0.001), costochondral joint (odds ratio = 0.311, P = 0.013), sternoclavicular joint (odds ratio = 0.163, P = 0.017) and manubriosternal joint (odds ratio = 0.171, P = 0.021) were associated with RP patients without CNS involvement, respectively. In contrast to RP patients without CNS involvement, the incidence of ear involvement was higher in RP patients with CNS involvement. After controlling the potential confounding factor sex and the admission age, hypertension and involvement of eye and heart were related with RP patients with CNS involvement, respectively.

Polishing the crystal ball: mining multi-omics data in dermatomyositis

Precision medicine, which recognizes and upholds the uniqueness of each individual patient and the importance of discerning these inter-individual differences on a molecular scale in order to provide truly personalized medical care, is a revolutionary approach that relies on the discovery of clinically-relevant biomarkers derived from the massive amounts of data generated by epigenomic, genomic, transcriptomic, proteomic, microbiomic, and metabolomic studies, collectively known as multi-omics. If harnessed and mined appropriately with the help of ever-evolving computational and analytic methods, the collective data from omics studies has the potential to accelerate delivery of targeted medical treatment that maximizes benefit, minimizes harm, and eliminates the “fortune-telling” inextricably linked to the prevailing trial-and-error approach. For a disease such as dermatomyositis (DM), which is characterized by remarkable phenotypic heterogeneity and varying degrees of multi-organ involvement, an individualized approach that incorporates big data derived from multi-omics studies with the results of currently available serologic, histopathologic, radiologic, and electrophysiologic tests, and, most importantly, with clinical findings obtained from a thorough history and physical examination, has immense diagnostic, therapeutic, and prognostic value. In this review, we discuss omics-based research studies in DM and describe their practical applications and promising roles in guiding clinical decisions and optimizing patient outcomes.

Environmental triggers of dermatomyositis: a narrative review

Dermatomyositis (DM) is an autoimmune disease that affects the skin, lungs, and muscle. Although the pathogenesis of DM is not completely understood, several environmental triggers have been linked to DM onset or flare. This article specifically examines the effects of herbal supplements, drugs, infections, ultraviolet (UV) radiation, and environmental pollutants on the onset or exacerbation of DM. Herbal supplements such as Spirulina platensis, Aphanizomenon flos-aquae, Chlorella, Echinacea, and Alfalfa have been implicated and are frequently used in health foods. Medications such as hydroxyurea, TNF-α inhibitors, immune checkpoint inhibitors (ICI), and penicillamine, as well as certain viral infections, such as parvovirus B19, coxsackie virus, polyomavirus, Epstein-Barr virus (EBV), hepatitis, influenza, and human immunodeficiency viruses (HIV) have been associated with DM onset. Bacterial infections and vaccinations have also been linked to the development of DM. Additional environmental factors, including UV radiation and air pollutants, such as silica, biological/mineral dust, and particulate air matter from vehicle and industrial emissions, may also play a role in DM pathogenesis. Overall, there is general agreement that an autoimmune attack of the skin, muscle, and lungs in DM can be triggered by various environmental factors and warrants further investigation.

Prevalence of interstitial lung disease in polymyositis and dermatomyositis: A meta-analysis from 2000 to 2020

OBJECTIVE

Interstitial lung disease (ILD) is the most important prognostic factor for mortality in patients with polymyositis (PM) and dermatomyositis (DM), but the prevalence of ILD in PM/DM may vary between countries. The aim of this study was to determine the overall prevalence of ILD in global patients with PM/DM.

METHODS

We performed a systematic literature review of studies published from Jan 1, 2000 to April 30, 2020 on ILD and PM/DM. We extracted data and pooled the prevalence by using a random-effect model due to high heterogeneity. Heterogeneity was assessed by subgroup analysis and sensitivity analysis.

RESULTS

A total of 34 studies with 10,130 patients were included in our meta-analysis. Pooled data demonstrated that the global prevalence of ILD in patients with PM/DM was 0.41 (95% confidence interval [CI] 0.35-0.48). However, this prevalence varied with geographical locations and time trends. The prevalence of ILD in PM/DM was 0.5 (95% CI 0.42-0.57) in Asia, 0.23 (95% CI 0.15-0.31) in America, and 0.26 (95% CI 0.18-0.34) in Europe. A higher prevalence of ILD was reported in studies published in 2011-2015 (0.43, 95% CI 0.34-0.52) and 2016-2020 (0.45, 95% CI 0.35-0.54), compared with those published in 2000-2010 (0.27, 95% CI 0.16-0.39). The pooled prevalence of ILD in patients with DM, PM, and clinically amyopathic dermatomyositis subtype was 0.42 (95% CI 0.35-0.49), 0.35 (95% CI 0.27-0.42), and 0.53 (95% CI 0.32-0.74), respectively. Patients with anti-Jo-1 and anti-melanoma differentiation-associated gene 5 antibodies were more likely to develop ILD than other myositis-specific autoantibodies.

CONCLUSION

The global prevalence of ILD in patients with PM/DM was approximately 41% and the condition was predominant in Asians. This highlights potential genetic and environmental differences in the pathogenesis of ILD in patients with PM/DM. More studies are required to elucidate the specific associations.

Epstein-Barr Virus and Systemic Autoimmune Diseases

Epstein-Barr Virus (EBV) is an extremely successful human herpes virus, which infects essentially all human beings at some time during their life span. EBV infection and the associated immune response results in production of antibodies (seroconversion), which occurs mainly during the first years of life, but may also happen during adolescence or later in life. Infection of adolescents can result in infectious mononucleosis, an acute serious condition characterized by massive lymphocytosis. Transmission of EBV mainly occurs through saliva but can rarely be spread through semen or blood, e.g. through organ transplantations and blood transfusions. EBV transmission through oral secretions results in infection of epithelial cells of the oropharynx. From the epithelial cells EBV can infect B cells, which are the major reservoir for the virus, but other cell types may also become infected. As a result, EBV can shuttle between different cell types, mainly B cells and epithelial cells. Moreover, since the virus can switch between a latent and a lytic life cycle, EBV has the ability to cause chronic relapsing/reactivating infections. Chronic or recurrent EBV infection of epithelial cells has been linked to systemic lupus erythematosus and Sjögren’s syndrome, whereas chronic/recurrent infection of B cells has been associated with rheumatoid arthritis, multiple sclerosis and other diseases. Accordingly, since EBV can shuttle between epithelial cells and B cells, the systemic autoimmune diseases often occur as overlapping syndromes with symptoms and characteristic autoantibodies (e.g. antinuclear antibodies and rheumatoid factors) reflecting epithelial and/or B cell infection.

Insights into pathogenesis and clinical implications in myositis-associated interstitial lung diseases

PURPOSE OF REVIEW

Interstitial lung diseases (ILDs) have been reported to be associated with myositis (including polymyositis and dermatomyositis). These myositis-associated ILDs carry significant morbidity and mortality. This review summarizes recent findings on myositis-associated ILD with a focus on pathogenesis and emerging treatment.

RECENT FINDINGS

Recent advances in genetics have revealed 22 myositis-associated genome-wide loci, which were significantly enriched in regulatory regions in immune cells. An analysis of such disease-associated loci elucidated potential drug targets (e.g., TYK2 targeted by tofacitinib). In another study, an intronic variant in WDFY4 in association with clinically amyopathic dermatomyositis (CADM) had an effect for higher expression of a truncated WDFY4 isoform. Truncated WDFY4 markedly enhanced the MDA5-mediated NF-κB activation and cell apoptosis, indicating the dysregulated WDFY4-MDA5 pathway as a novel pathogenesis of CADM. As a novel strategy, tofacitinib treatment showed a promising improvement in survival and clinical features of CADM-associated ILD.

SUMMARY

The genetic differences in the myositis-susceptible loci may explain the heterogeneous phenotypes and treatment responses in myositis-associated ILD. The understanding of pathogenesis with the genetic background as well as autoantibodies will enable the practice of personalized treatment in the management of the disease.

Genetics of idiopathic inflammatory myopathies: insights into disease pathogenesis

To review the advances that have been made in our understanding of the genetics of idiopathic inflammatory myopathies (IIM) in the past 2 years, with a particular focus on dermatomyositis and polymyositis.

Questions and Answers on Smoking in Patients With Diffuse ILD. Use of PICO Methodology

INTRODUCTION

The Smoking and the Diffuse Interstitial Lung Diseases (ILD) groups of ALAT and SEPAR collaborated in the preparation of this document.

MATERIALS AND METHODS

This document uses PICO methodology to answer various questions on the relationship between tobacco use and diffuse ILD.

RESULTS AND CONCLUSIONS

The main recommendations are: a) moderate level of evidence and strong recommendation to consider smoking as a risk factor for the development and/or modification of the progression of diffuse ILD; b) moderate level of evidence to identify an increase in mortality in diffuse ILD, irrespective of histologic pattern. Low evidence for ascribing it to smoking and strong recommendation for the early identification of patients with diffuse ILD. Further studies are needed to evaluate the effect of smoking cessation in patients with diffuse ILD; c) low level of evidence and weak recommendation for defining the impact of passive smoking in diffuse ILD; d) low level of evidence to demonstrate that smoking cessation improves the outcomes of patients diagnosed with diffuse ILD and strong recommendation to advise smoking cessation in smokers with diffuse ILD, and e) low level of evidence to support the clinical or epidemiological usefulness of active case finding for diffuse ILD in smoking cessation programs, and strong recommendation justifying the performance of spirometry in active case finding, based not on current smoking status, but on previous accumulated consumption, even in asymptomatic cases.

Association of African-American ethnicity and smoking status with total and individual damage index in systemic lupus erythematosus

INTRODUCTION

Smoking has been associated with increased incidence, severity of cutaneous lupus, and lupus activity. We looked at the association of both smoking and ethnicity with the individual damage items from the SLICC/ACR Damage Index.

METHODS

Poisson regression was used to model the total SLICC/ACR Damage Index score against ever smoking. Cox regression was used to assess the relationship between time to individual damage items and ever smoking. Furthermore, we compared SLICC/ACR Damage Index items among African-American and Caucasian ever smokers.

RESULTS

The study included 2629 patients, 52.6% Caucasian and 39.3% African-American. The prevalence of ever smokers was 35.8%. There was no significant difference in total SLICC/ACR Damage Index score between ever smokers and never smokers after adjustment for ethnicity, gender, age at diagnosis, and years of education. Ever smokers had more atherosclerotic cardiovascular damage and skin damage compared to non-smokers. Caucasian SLE patients who ever smoked were more likely to have muscle atrophy and atherosclerosis compared to Caucasian non-smokers. African-American patients who ever smoked were more likely to have skin damage compared to African-American non-smokers. African-Americans who smoked were more likely to have many more damage items (cataract, renal damage, pulmonary hypertension, cardiomyopathy, deforming or erosive arthritis, avascular necrosis, skin damage, and diabetes) compared to Caucasians who smoked.

CONCLUSION

Our analysis proved the major effect of smoking on cardiovascular and cutaneous damage. Surprisingly, cardiovascular damage items had higher hazard ratios in Caucasian smokers than non-smokers while skin damage items hazard ratios were higher in African-American smokers compared to non-smokers.Key Points• This study is the largest cohort study to date evaluating the effect of smoking on the cumulative SLICC/ACR Damage Index and its individual damage items.• It is the only study that examined the effect of smoking on individual items of the SLICC/ACR Damage Index in terms of Caucasians vs. African-American ethnicity.• Our analysis proved the major effect of smoking on cardiovascular and cutaneous damage. Compared to non-smokers, Caucasian smokers had higher risk of cardiovascular damage while African-American smokers had more skin damage.• African-Americans who smoked were more likely to have many more damage items (cataract, renal damage, pulmonary hypertension, cardiomyopathy, deforming or erosive arthritis, avascular necrosis, skin damage, and diabetes) compared to Caucasians who smoked.

Polymyositis and dermatomyositis - challenges in diagnosis and management

Polymyositis (PM) and dermatomyositis (DM) are different disease subtypes of idiopathic inflammatory myopathies (IIMs). The main clinical features of PM and DM include progressive symmetric, predominantly proximal muscle weakness. Laboratory findings include elevated creatine kinase (CK), autoantibodies in serum, and inflammatory infiltrates in muscle biopsy. Dermatomyositis can also involve a characteristic skin rash. Both polymyositis and dermatomyositis can present with extramuscular involvement. The causative factor is agnogenic activation of immune system, leading to immunologic attacks on muscle fibers and endomysial capillaries. The treatment of choice is immunosuppression. PM and DM can be distinguished from other IIMs and myopathies by thorough history, physical examinations and laboratory evaluation and adherence to specific and up-to-date diagnosis criteria and classification standards. Treatment is based on correct diagnosis of these conditions.

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Challenges of diagnosis and management influences the clinical research and practice of Polymyositis and dermatomyositis.

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Diagnostic criteria have been updated and novel therapies have been developed in PM/DM.

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Pathogenesis investigation and diagnosis precision improvement may help to guide future treatment strategies.

Recent developments in classification criteria and diagnosis guidelines for idiopathic inflammatory myopathies

Purpose of review

The aim of this review was to summarize key developments in classification and diagnosis of the idiopathic inflammatory myopathies (IIMs).

Recent findings

The recently published European League Against Rheumatism/American College of Rheumatology (EULAR/ACR) classification criteria for the IIMs provide a comprehensive, accurate and data-driven approach to identification of IIM cases appropriate for inclusion in research studies. Further, recent studies have advanced understanding of clinical manifestations of the IIMs and delineated the role of imaging, particularly magnetic resonance.

Summary

The recent publication of the EULAR/ACR classification criteria will potentially greatly improve IIM research through more accurate case identification and standardization across studies.

Future inclusion of newly recognized clinical associations with the MSAs may further improve the criteria's accuracy and utility. Clear and comprehensive understanding of associations between clinical manifestations, prognosis and multisystem involvement can aid diagnostic assessment; recent advances include delineation of such associations and expansion of the role of imaging.

Dermatomyositis etiopathogenesis: a rebel soldier in the muscle

PURPOSE OF REVIEW

The purpose of this article is to review the etiopathogenesis of dermatomyositis, including the predisposing factors, triggers, inflammatory cells, pathways and target antigens associated with dermatomyositis.

RECENT FINDINGS

During the last few years, we have made considerable progress in unveiling the etiopathogenesis of dermatomyositis. In the first place, we have defined genes within the major histocompatibility complex locus as the greatest genetic risk factor for the disease. Second, we have demonstrated that certain environmental factors, as well as tumors, may trigger certain dermatomyositis subtypes. Moreover, we have established the importance of the interferon pathway in dermatomyositis pathogenesis compared with other myositis subtypes. But probably, the most remarkable advance has been the discovery of multiple autoantibodies that define groups of patients with characteristic clinical features, prognosis and response to treatment.

SUMMARY

Dermatomyositis cause and pathogenesis have proven to be a complex and fascinating task for the scientific community and the last decade has been full of new findings on how the disease starts and how it causes damage to different organ systems. However, we have still more questions than answers in this topic, answers that will be critical to understanding autoimmunity and finding effective therapies to dermatomyositis.