In adult onset myositis, the presence of interstitial lung disease and myositis specific/associated antibodies are governed by HLA class II haplotype, rather than by myositis subtype

Distinct HLA associations with autoantibody-defined subgroups in idiopathic inflammatory myopathies

BACKGROUND

In patients with idiopathic inflammatory myopathies (IIM), autoantibodies are associated with specific clinical phenotypes suggesting a pathogenic role of adaptive immunity. We explored if autoantibody profiles are associated with specific HLA genetic variants and clinical manifestations in IIM.

METHODS

We included 1348 IIM patients and determined the occurrence of 14 myositis-specific or -associated autoantibodies. We used unsupervised cluster analysis to identify autoantibody-defined subgroups and logistic regression to estimate associations with clinical manifestations, HLA-DRB1, HLA-DQA1, HLA-DQB1 alleles, and amino acids imputed from genetic information of HLA class II and I molecules.

FINDINGS

We identified eight subgroups with the following dominant autoantibodies: anti-Ro52, -U1RNP, -PM/Scl, -Mi2, -Jo1, -Jo1/Ro52, -TIF1γ or negative for all analysed autoantibodies. Associations with HLA-DRB1∗11, HLA-DRB1∗15, HLA-DQA1∗03, and HLA-DQB1∗03 were present in the anti-U1RNP-dominated subgroup. HLA-DRB1∗03, HLA-DQA1∗05, and HLA-DQB1∗02 alleles were overrepresented in the anti-PM/Scl and anti-Jo1/Ro52-dominated subgroups. HLA-DRB1∗16, HLA-DRB1∗07 alleles were most frequent in anti-Mi2 and HLA-DRB1∗01 and HLA-DRB1∗07 alleles in the anti-TIF1γ subgroup. The HLA-DRB1∗13, HLA-DQA1∗01 and HLA-DQB1∗06 alleles were overrepresented in the negative subgroup. Significant signals from variations in class I molecules were detected in the subgroups dominated by anti-Mi2, anti-Jo1/Ro52, anti-TIF1γ, and the negative subgroup.

INTERPRETATION

Distinct HLA class II and I associations were observed for almost all autoantibody-defined subgroups. The associations support autoantibody profiles use for classifying IIM which would likely reflect underlying pathogenic mechanisms better than classifications based on clinical symptoms and/or histopathological features.

FUNDING

See a detailed list of funding bodies in the Acknowledgements section at the end of the manuscript.

Delphi-Based Consensus on Interstitial Lung Disease Screening in Patients with Connective Tissue Diseases (Croatian National-Based Study)

The aim of this study was to develop a Croatian Delphi-based expert consensus for screening interstitial lung disease (ILD) associated with connective tissue disease (CTD). A systematic literature review was conducted on risk factors for the development of ILD, prevalence and incidence of ILD, diagnostic and screening methods for ILD, and prognosis of ILD in idiopathic inflammatory myopathy (IIM), mixed connective tissue disease (MCTD), primary Sjögren's syndrome (pSS), rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), and systemic sclerosis (SSc) were performed. Based on the evidence found, experts developed questionnaires for screening and monitoring ILD in each CTD, which were provided via an online survey. Following the electronic survey, two screening algorithms were developed based on the consensus opinions. The detection strategy for ILD included high-resolution computed tomography (HRCT) in addition to pulmonary function testing for IIM, MCTD, and SSc. and pulmonary function testing for newly diagnosed pSS, RA and SLE. However, in patients with identified risk factors for ILD HRCT, these tests should also be performed. A screening strategy for early identification of patients with various CTD-ILD was first developed by a multidisciplinary team of rheumatologists, pulmonologists, and radiologists to identify early CTD patients at risk of ILD, a severe extra-articular manifestation of CTD.

Imputation of the major histocompatibility complex region identifies major independent variants associated with bullous pemphigoid and dermatomyositis in Han Chinese

As autoimmune skin diseases, both bullous pemphigoid (BP) and dermatomyositis (DM) show significant associations with the major histocompatibility complex (MHC) region. In fact, the coexistence of BP and DM has been previously reported. Therefore, we hypothesized that there may be a potential genetic correlation between BP and DM. Based on data for 312 BP patients, 128 DM patients, and 6793 healthy control subjects, in the MHC region, we imputed single-nucleotide polymorphisms (SNP), insertions and deletions (INDEL), and copy number variations (CNV) using the 1KGP phase 3 dataset and amino acids (AA) and SNP using a Han-MHC reference database. An association study revealed the most significant SNP associated with BP, namely, rs580921 (p = 1.06E-08, odds ratio [OR] = 1.61, 95% confidence interval [CI] = 1.37-1.90), which is located in the C6orf10 gene, and the most significant classic human leukocyte antigen (HLA) allele associated with DM, namely, HLA-DPB1*1701 (p = 6.56E-10, OR = 3.61, 95% CI = 2.40-5.42). Further stepwise regression analyses with rs580921 identified a threonine at position 163 of the HLA-B gene as a new independent disease-associated AA, and HLA-DPB1*1701 indicated that no loci were significant. Three-dimensional ribbon models revealed that the HLA-B AA position 163 (p = 3.93E-07, OR = 1.64, 95% CI = 1.35-1.98) located in the α2 domain of the HLA-B molecule was involved in the process of specific antigen presentation. The calculations showed that there was no significant genetic correlation between BP and DM. Our study identified three significant loci in the MHC region, proving that the HLA region was significantly correlated with BP and DM separately. Our research highlights the key role of the MHC region in disease susceptibility.

Association with HLA-DRβ1 position 37 distinguishes juvenile Dermatomyositis from adult-onset myositis

Objectives

Juvenile dermatomyositis (JDM) is a rare, severe autoimmune disease and the most common idiopathic inflammatory myopathy (IIM) of children. JDM and adult-onset dermatomyositis (DM) have similar clinical, biological and serological features, although these features differ in prevalence between childhood-onset and adult-onset disease, suggesting age of disease onset may influence pathogenesis. Therefore, a JDM-focused genetic analysis was performed using the largest collection of JDM samples to date.

Methods

Caucasian JDM samples (n = 952) obtained via international collaboration were genotyped using the Illumina HumanCoreExome chip. Additional non-assayed HLA loci and genome-wide SNPs were imputed.

Results

HLA-DRB1*03:01 was confirmed as the classical HLA allele most strongly associated with JDM (OR 1.66; 95% CI 1.46, 1.89; P = 1.4 × 10−14), with an independent association at HLA-C*02:02 (OR = 1.74; 95% CI 1.42, 2.13, P = 7.13 × 10−8). Analyses of amino acid positions within HLA-DRB1 indicated the strongest association was at position 37 (omnibus P = 3.3 × 10−19), with suggestive evidence this association was independent of position 74 (omnibus P = 5.1 × 10−5), the position most strongly associated with adult-onset DM. Conditional analyses also suggested the association at position 37 of HLA-DRB1 was independent of some alleles of the Caucasian HLA 8.1 ancestral haplotype (AH8.1) such as HLA-DQB1*02:01 (OR = 1.62; 95% CI 1.36, 1.93; P = 8.70 × 10−8), but not HLA-DRB1*03:01 (OR = 1.49; 95% CR 1.24, 1.80; P = 2.24 × 10−5). No associations outside the HLA region were identified.

Conclusions

Our findings confirm previous associations with AH8.1 and HLA-DRB1*03:01, HLA-C*02:02 and identify a novel association with amino acid position 37 within HLA-DRB1 which may distinguish JDM from adult DM.

Myositis Antibodies and Interstitial Lung Disease

BACKGROUND

Interstitial lung disease (ILD) comprises a heterogeneous group of inflammatory and fibrotic conditions, often resulting in progressive lung function decline and increased mortality. Connective tissue disease (CTD) should be considered in all patients with ILD, as distinguishing between CTD-ILD and other forms of fibrotic lung disease has important therapeutic and prognostic implications. The idiopathic inflammatory myopathies (IIM) represent a CTD subtype of growing interest to ILD experts. The expansion and availability of myositis-specific and myositis-associated antibody testing has allowed for improved disease detection and characterization.

CONTENT

In this review, we highlight the relationship between myositis antibodies and ILD. Select forms of IIM, such as the antisynthetase syndrome and clinically amyopathic dermatomyositis can present with rapidly progressive ILD, warranting timely disease diagnosis and management. Disease phenotypes, prevalence, laboratory testing, prognosis, and management strategies are described according to select myositis antibodies.

SUMMARY

Myositis antibodies provide valuable information for clinicians managing patients with ILD. This review aims to increase awareness of their role in disease detection, pathophysiology, and possibly therapeutics.

Role of MUC1 rs4072037 polymorphism and serum KL-6 levels in patients with antisynthetase syndrome

Mucin 1/Krebs von den Lungen-6 (KL-6) is proposed as a serum biomarker of several interstitial lung diseases (ILDs), including connective tissue disorders associated with ILD. However, it has not been studied in a large cohort of Caucasian antisynthetase syndrome (ASSD) patients. Consequently, we assessed the role of MUC1 rs4072037 and serum KL-6 levels as a potential biomarker of ASSD susceptibility and for the differential diagnosis between patients with ILD associated with ASSD (ASSD-ILD +) and idiopathic pulmonary fibrosis (IPF). 168 ASSD patients (149 ASSD-ILD +), 174 IPF patients and 523 healthy controls were genotyped for MUC1 rs4072037 T > C. Serum KL-6 levels were determined in a subgroup of individuals. A significant increase of MUC1 rs4072037 CC genotype and C allele frequencies was observed in ASSD patients compared to healthy controls. Likewise, MUC1 rs4072037 TC and CC genotypes and C allele frequencies were significantly different between ASSD-ILD+ and IPF patients. Additionally, serum KL-6 levels were significantly higher in ASSD patients compared to healthy controls. Nevertheless, no differences in serum KL-6 levels were found between ASSD-ILD+ and IPF patients. Our results suggest that the presence of MUC1 rs4072037 C allele increases the risk of ASSD and it could be a useful genetic biomarker for the differential diagnosis between ASSD-ILD+ and IPF patients.

Interstitial Lung Disease in Connective Tissue Disease: A Common Lesion With Heterogeneous Mechanisms and Treatment Considerations

Connective tissue disease (CTD) related interstitial lung disease (CTD-ILD) is one of the leading causes of morbidity and mortality of CTD. Clinically, CTD-ILD is highly heterogenous and involves rheumatic immunity and multiple manifestations of respiratory complications affecting the airways, vessels, lung parenchyma, pleura, and respiratory muscles. The major pathological features of CTD are chronic inflammation of blood vessels and connective tissues, which can affect any organ leading to multi-system damage. The human lung is particularly vulnerable to such damage because anatomically it is abundant with collagen and blood vessels. The complex etiology of CTD-ILD includes genetic risks, epigenetic changes, and dysregulated immunity, which interact leading to disease under various ill-defined environmental triggers. CTD-ILD exhibits a broad spectra of clinical manifestations: from asymptomatic to severe dyspnea; from single-organ respiratory system involvement to multi-organ involvement. The disease course is also featured by remissions and relapses. It can range from stability or slow progression over several years to rapid deterioration. It can also present clinically as highly progressive from the initial onset of disease. Currently, the diagnosis of CTD-ILD is primarily based on distinct pathology subtype(s), imaging, as well as related CTD and autoantibodies profiles. Meticulous comprehensive clinical and laboratory assessment to improve the diagnostic process and management strategies are much needed. In this review, we focus on examining the pathogenesis of CTD-ILD with respect to genetics, environmental factors, and immunological factors. We also discuss the current state of knowledge and elaborate on the clinical characteristics of CTD-ILD, distinct pathohistological subtypes, imaging features, and related autoantibodies. Furthermore, we comment on the identification of high-risk patients and address how to stratify patients for precision medicine management approaches.

HLA association with the susceptibility to anti-synthetase syndrome

OBJECTIVE

To investigate the human leukocyte antigen (HLA) association with anti-synthetase syndrome (ASSD).

METHODS

We conducted the largest immunogenetic HLA-DRB1 and HLA-B study to date in a homogeneous cohort of 168 Caucasian patients with ASSD and 486 ethnically matched healthy controls by sequencing-based-typing.

RESULTS

A statistically significant increase of HLA-DRB1*03:01 and HLA-B*08:01 alleles in patients with ASSD compared to healthy controls was disclosed (26.2% versus 12.2%, P=1.56E-09, odds ratio-OR [95% confidence interval-CI]=2.54 [1.84-3.50] and 21.4% versus 5.5%, P=18.95E-18, OR [95% CI]=4.73 [3.18-7.05]; respectively). Additionally, HLA-DRB1*07:01 allele was significantly decreased in patients with ASSD compared to controls (9.2% versus 17.5%, P=0.0003, OR [95% CI]=0.48 [0.31-0.72]). Moreover, a statistically significant increase of HLA-DRB1*03:01 allele in anti-Jo-1 positive compared to anti-Jo-1 negative patients with ASSD was observed (31.8% versus 15.5%, P=0.001, OR [95% CI]=2.54 [1.39-4.81]). Similar findings were observed when HLA carrier frequencies were assessed. The HLA-DRB1*03:01 association with anti-Jo-1 was unrelated to smoking history. No HLA differences in patients with ASSD stratified according to the presence/absence of the most representative non-anti-Jo-1 anti-synthetase autoantibodies (anti-PL-12 and anti-PL-7), arthritis, myositis or interstitial lung disease were observed.

CONCLUSIONS

Our results support the association of the HLA complex with the susceptibility to ASSD.

Geographical Latitude Remains as an Important Factor for the Prevalence of Some Myositis Autoantibodies: A Systematic Review

The idiopathic inflammatory myopathies (IIM) are characterized by muscular weakness, cutaneous manifestations, muscle damage revealed by increase of muscular enzymes, muscle biopsy, electromyography and changes on magnetic resonance imaging. However, the hallmark of these IIM, is the development of myositis specific antibodies (MSA) or myositis associated antibodies (MAA). The theories about their presence in the serum of IIM is not known. Some studies have suggested that some of these MSA, such as anti-Mi-2 increases according to the intensity of UV radiation. There is scarce information about the environmental factors that might contribute in order to be considered as triggering factors as UV radiation might be. In this review, we analyzed the reported prevalence of MSAs and MAAs regarding to their geographical location and the possible relation with UV radiation. We collected the prevalence data of fifteen MSA and thirteen MAA from 22 countries around the world and we were able to observe a difference in prevalence between countries and continents. We found differences in anti-PL7, anti-Ro52, anti-La and anti-Ku prevalence according to UV radiation level. Otherwise, we observed that anti-Mi-2 prevalence increases near to the Equator meanwhile anti-MJ/NXP2 and anti-ARS prevalence had an opposite behavior increasing their prevalence in the geographical locations farther to the Equator. Our results highlighted the importance to include the UV radiation and other environmental factors in IIM studies, in order to clarify its association with MSA and MAA prevalence as well as its possible role in the immunopathogenesis of these diseases.

Detection of multiple myositis-specific autoantibodies in unique patients with idiopathic inflammatory myopathy: A single centre-experience and literature review: Systematic review

INTRODUCTION

Myositis-specific autoantibodies (MSAs) are thought to be mutually exclusive in patients with idiopathic inflammatory myopathies (IIM) based on studies with immunoprecipitation-based (IP) detection methods. Recently, detection of multiple MSAs in unique patients is increasingly reported, but the extent of this phenomenon remains unclear.

METHODS

At our centre, we reviewed results from two line immunoassays and one dot immunoassay in 145 IIM patients and 240 controls for the presence of multiple MSAs. Pubmed and Embase were systematically searched for articles mentioning detection of multiple MSAs in IIM patients, published until February 2019. We assessed the frequency, detection method, the precise combinations and clinical phenotypes of participants with multiple MSAs.

RESULTS

At our centre, detection of multiple MSAs occurred in 3.4-8.3% of patients with IIM, depending on the assay. However, no cases with full concordance across all three assays were identified. Forty-four articles reported detection of multiple MSAs, representing a total of 133 cases, including four patients with a connective tissue disease other than IIM and two healthy controls. In 101 cases all MSAs were detected using only one detection method: 40 cases with IP-based methods (most frequently used technique) and 61 cases with other assay types. In most cases the phenotype of patients with multiple MSAs matched the predicted presentation associated with one MSA and in few cases the phenotype matched with both MSAs.

CONCLUSION

Detection of multiple MSAs in unique IIM patients is less rare than commonly accepted. Specificity issues of the commercially available multiplex immunoassays may, at least partly, explain the higher frequency compared to IP-based methods. 'True multiple MSA-positive' patients may exist, though they are most likely rare.

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.

Dermatomyositis autoantibodies: how can we maximize utility?

The past 15 years has seen significant advances in the characterization of myositis-specific autoantibodies (MSAs) and their associated phenotypes in patients with dermatomyositis (DM). As more careful studies are performed, it is clear that unique combinations of clinical and pathological phenotypes are associated with each MSA, despite the fact that there is considerable heterogeneity within antibody classes as well as overlap across the groups. Because risk for interstitial lung disease (ILD), internal malignancy, adverse disease trajectory, and, potentially response to therapy differ by DM MSA group, a deeper understanding of MSAs and validation and standardization of assays used for detection are critical for optimizing diagnosis and treatment. Like any test, the diagnostic sensitivity and specificity of assays for various MSAs is not perfect. Currently tests for MSAs are helpful at minimum for a clinician to assess relative risk or contribute to diagnosis and perhaps counsel the appropriate patient about what to expect. With international standardization and larger studies it is likely that more antibody tests will make their way into formal schemata for diagnosis and actionable risk assessment in DM. In this review, we summarize key considerations for interpreting the clinical and pathologic associations with MSA in DM and identify critical gaps in knowledge and practice that will maximize their clinical utility and utility for understanding disease pathogenesis.

Single Nucleotide Polymorphism in the IL17A Gene Is Associated with Interstitial Lung Disease Positive to Anti-Jo1 Antisynthetase Autoantibodies

Antisynthetase syndrome (ASSD) is a rare multisystemic connective tissue disease affecting the skin, joints, muscles, and lungs, characterized by anti-aminoacyl transfer-RNA-synthetases (anti-tRNA) autoantibodies production, being anti-Jo1 the most frequent. We included one-hundred twenty-one ASSD patients and 340 healthy subjects (HS), and also, we divided the case group into anti-Jo1 and non-anti-Jo1. Two single nucleotide polymorphisms (SNPs) in the IL17A gene were evaluated. Anti-Jo1 was the most common anti-tRNA antibody in our cohort, and the most frequent tomographic pattern was non-specific interstitial pneumonia (NSIP). Anti-Jo1 ASSD patients had higher levels of creatine phosphokinase than the non-anti-Jo1 group. Significant differences in genotype frequencies with rs8193036/CC between anti-Jo1 vs. non-anti-Jo1 ASSD patients (p < 0.001), maintaining the association after Bonferroni correction (p = 0.002). Additionally, in the anti-Jo1 group vs. HS comparison, we found a statistically significant difference with the same SNP (p = 0.018, OR = 2.91, 95% CI = 1.15-7.35), maintaining the association after Bonferroni correction (p = 0.036). The rs8193036/CC genotype in IL17A is associated with ASSD patients with anti-Jo1. Also, anti-Jo1 and non-anti-Jo1 patients display differences in genotype frequencies.

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.

A 65-year-old Woman With Persistent Dyspnea, Arthritis, and Raynaud's Phenomenon

Antisynthetase syndrome (AS) is a rare disease that affects patients with inflammatory myopathies such as polymyositis (PM) and dermatomyositis (DM). In patients with AS, up to 95% of patients develop antisynthetase syndrome-associated interstitial lung disease (AS-ILD). Although AS-ILD commonly occurs in patients with a well-established diagnosis of AS, it can be the first or only manifestation of an occult AS. The frequency of interstitial lung disease (ILD), myopathy, and skin involvement are often dependent on the type of myositis-specific antibodies present. AS-ILD patients who are positive for both anti-Jo-1 and anti-SSA/RO-52 autoantibodies often present with a severe degree of lung restriction on pulmonary function tests and radiologic imaging with an inadequate response toward immunosuppressive therapies. We describe a 65-year-old woman who presents with chronic dyspnea. She was initially diagnosed with corticosteroid-resistant cryptogenic organizing pneumonia based on the radiological findings on her CT chest. Her symptoms did not improve, and she suffered from intolerable corticosteroid-related side effects. Reviews of systems were positive for arthritis and Raynaud's phenomenon. She was found to have elevated inflammatory markers and autoantibodies such as anti-Jo-1, anti-RO-52, and anti-SSA. A diagnosis of AS-ILD resistant to corticosteroid therapy was made. Her lung function improved with combination therapy of mycophenolate and rituximab. Our case highlights that a detailed history and physical exam, compatible radiologic imaging, and autoantibodies are essential for the diagnosis of AS-ILD.

A major genetic determinant of autoimmune diseases is associated with the presence of autoantibodies in hypersensitivity pneumonitis

Background

Hypersensitivity pneumonitis is an immune-mediated disease triggered by exposure to organic particles in susceptible individuals. It has been reported that a subgroup of patients with hypersensitivity pneumonitis develops autoantibodies with or without clinical manifestations of autoimmune disease. However, the mechanisms involved in this process and the effect of the autoantibodies on clinical course in hypersensitivity pneumonitis is unknown. We evaluated the association between human leukocyte antigen (HLA) class II alleles and hypersensitivity pneumonitis patients with and without autoantibodies.

Methods

170 hypersensitivity pneumonitis patients were included. We analysed the presence of antinuclear antibodies, rheumatoid factor, anti-SSA/Ro, anti-SSB/La and anti-CCP at the time of diagnosis. In addition, in a subset of patients we evaluated anti-Scl-70, anti-neutrophil cytoplasmic antibody, and anti-DNA. HLA typing was performed using PCR sequence-specific primers in a high-resolution modality, including HLA-DRB1 and HLA-DQB1 loci. Statistical analysis was performed employing Epi-Info v7 and SPSS v20.

Results

60 hypersensitivity pneumonitis patients showed sera autoantibodies (HPAbs⁺), and 110 hypersensitivity pneumonitis patients did not (HPAbs⁻). The frequency of the allele HLA-DRB1*03:01 was remarkably increased in the HPAbs⁺ group (10.8% versus 0.45%; OR 30.14, 95% CI 3.83–237.1; p=1.65×10^-4 after Bonferroni's correction). Likewise, we found that the haplotype DRB1*03:01-DQB1*02:01, which is part of the 8.1 ancestral haplotype, a major genetic determinant of autoimmune diseases, confers significant risk to develop autoantibodies (OR 19.23, 95% CI 2.37–155.9; p=0.0088 after Bonferroni's correction). In addition, the HLA-DRB1*03:01 allele was associated with higher mortality in patients with hypersensitivity pneumonitis (adjusted OR 5.9, 95% CI 1.05–33.05; p=0.043).

Conclusions

A subset of hypersensitivity pneumonitis patients presents circulating autoantibodies and higher mortality that are associated with some alleles of 8.1 ancestral haplotype.

Alleles from 8.1 ancestral haplotype (#HLA-DRB1 and DQB1 loci) are associated with #autoantibodies production in #hypersensitivity #pneumonitis in a cohort of Mexican mestizo patientshttps://bit.ly/3bprPeB

Antisynthetase syndrome pathogenesis: knowledge and uncertainties

PURPOSE OF REVIEW

Antisynthetase syndrome (ASyS) is an acquired myopathy characterized by the presence of myositis-specific autoantibodies directed against tRNA-synthetases. ASyS is potentially life threatening due to lung involvement and treatment remains a challenge to date. With symptoms not limited to muscles but also involving lung, skin and joints, ASyS appears specific and has a particular pathogenesis, different from the other inflammatory myopathies. This review is intended to discuss the current understanding of ASyS pathogenesis, pointing its current knowledge and also the crucial prospects that may lead to critical improvement of ASyS care.

RECENT FINDINGS

Regarding ASyS pathogenesis, initiation of the disease seems to arise in a multifactorial context, with first lesions occurring within the lungs. This may lead to aberrant self-antigen exposure and tolerance breakdown. The consequences are abnormal activation of both innate and adaptive immunity, resulting in the patients with favourable genetic background to autoimmune-mediated organ lesions. Immune and nonimmune roles of the antigen, as well as antigen presentation leading to specific T-cell and B-cell activation and to the production of specific autoantibodies belong to the disease process.

SUMMARY

This work aims to detail ASyS pathogenesis understanding, from initiation to the disease propagation and target tissue lesions, in order to considering future treatment directions.

Autoantibodies in myositis

The discovery of novel autoantigen systems related to idiopathic inflammatory myopathies (collectively referred to as myositis) in adults and children has had major implications for the diagnosis and management of this group of diseases across a wide range of medical specialties. Traditionally, autoantibodies found in patients with myositis are described as being myositis-specific autoantibodies (MSAs) or myositis-associated autoantibodies (MAAs), depending on their prevalence in other, related conditions. However, certain MSAs are more closely associated with extramuscular manifestations, such as skin and lung disease, than with myositis itself. It is very rare for more than one MSA to coexist in the same individual, underpinning the potential to use MSAs to precisely define genetic and disease endotypes. Each MSA is associated with a distinctive pattern of disease or phenotype, which has implications for diagnosis and a more personalized approach to therapy. Knowledge of the function and localization of the autoantigenic targets for MSAs has provided key insights into the potential immunopathogenic mechanisms of myositis. In particular, evidence suggests that the alteration of expression of a myositis-related autoantigen by certain environmental influences or oncogenesis could be a pivotal event linking autoantibody generation to the development of disease.

Human leukocyte antigen in Japanese patients with idiopathic inflammatory myopathy

Objective: The human leukocyte antigen (HLA) is the strongest genetic risk factor for idiopathic inflammatory myopathy (IIM), and different HLA alleles have been reported to be associated with IIM susceptibility among different ethnic groups. In this study, we have investigated HLA alleles associated with IIM in Japanese patients.Methods: Genotyping of HLA-DRB1 and DPB1 were performed in 252 Japanese IIM patients (166 dermatomyositis [DM] and 86 polymyositis [PM] patients) and the association was analyzed with comparison to controls (n = 1026 for DRB1 and n = 413 for DPB1).Results: DRB1*08:03 was associated with IIM (p = 1.60 × 10^-5, pc = .0005, odds ratio [OR] 2.11, 95% confidence interval [CI] 1.52-2.92) and DM (p = .0004, pc = .0128, OR 2.06, 95%CI 1.40-3.02). DPB1*05:01 was also associated with IIM (p = .0001, pc = .0021, OR 1.96, 95%CI 1.38-2.77) and DM (p = .0005, pc = .0075, OR 2.05, 95%CI 1.37-3.08). DRB1*09:01 (p = .0012, pc = .0368, OR 0.35, 95% CI 0.18-0.69) and DPB1*04:01(p = .0004, pc = .0057, OR 0.05, 95% CI 0.00-0.85) were protectively associated with PM. Two locus analyses suggested that DRB1*09:01 and DPB1*04:01 were independently associated with PM.Conclusion: Protective associations of HLA were detected in Japanese PM patients.

Successful classification of macrophage-mannose receptor CD206 in severity of anti-MDA5 antibody positive dermatomyositis associated ILD

Objectives

Macrophage-mannose receptor, CD206, is a marker of alternatively activated macrophages. Activated macrophages play key roles in DM. Interstitial lung disease (ILD) is a leading cause of mortality in patients with DM/clinically amyopathic DM (CADM). In particular, patients with the anti-melanoma differential gene 5 antibody (MDA5) frequently develop fatal rapid progressive ILD. This study aimed to evaluate the clinical implications of alternatively activated macrophages in patients with CADM/DM-ILD with anti-MDA5 antibody (MDA5-CADM/DM-ILD).

Methods

We measured serum concentrations of soluble CD206 (sCD206) in 33 patients with MDA5-CADM/DM-ILD and 36 age- and sex-matched control subjects. Expression levels of CD206 in the lungs from MDA5-CADM/DM-ILD were also examined.

Results

Patients with MDA5-CADM/DM-ILD had higher levels of sCD206 than those in controls (P < 0.0001). Of the 33 patients, 10 MDA5-CADM/DM-ILD patients developed fatal respiratory failure. Concentrations of sCD206 in patients with fatal ILD cases were significantly higher than those in the survivors, and increased sCD206 levels were associated with a higher mortality rate (Log-rank test, P = 0.0009). Age- and gender-adjusted logistic regression analyses showed that sCD206 was an independent prognostic factor for MDA5-CADM/DM-ILD. Importantly, assessment by sCD206 together with PaO2 successfully divided into three groups by their prognosis (P < 0.005, respectively). Pathological analyses showed accumulations of CD206-positive macrophages in lungs from the fatal case rather than those in the non-fatal cases.

Conclusions

Levels of serum sCD206 are increased in MDA5-CADM/DM-ILD and associated with poor prognosis. sCD206 is a potential biomarker to predict the severity of MDA5-CADM/DM-ILD.

Focused HLA analysis in Caucasians with myositis identifies significant associations with autoantibody subgroups

Objectives

Idiopathic inflammatory myopathies (IIM) are a spectrum of rare autoimmune diseases characterised clinically by muscle weakness and heterogeneous systemic organ involvement. The strongest genetic risk is within the major histocompatibility complex (MHC). Since autoantibody presence defines specific clinical subgroups of IIM, we aimed to correlate serotype and genotype, to identify novel risk variants in the MHC region that co-occur with IIM autoantibodies.

Methods

We collected available autoantibody data in our cohort of 2582 Caucasian patients with IIM. High resolution human leucocyte antigen (HLA) alleles and corresponding amino acid sequences were imputed using SNP2HLA from existing genotyping data and tested for association with 12 autoantibody subgroups.

Results

We report associations with eight autoantibodies reaching our study-wide significance level of p<2.9×10^–5. Associations with the 8.1 ancestral haplotype were found with anti-Jo-1 (HLA-B*08:01, p=2.28×10^–53 and HLA-DRB1*03:01, p=3.25×10^–9), anti-PM/Scl (HLA-DQB1*02:01, p=1.47×10^–26) and anti-cN1A autoantibodies (HLA-DRB1*03:01, p=1.40×10^–11). Associations independent of this haplotype were found with anti-Mi-2 (HLA-DRB1*07:01, p=4.92×10^–13) and anti-HMGCR autoantibodies (HLA-DRB1*11, p=5.09×10^–6). Amino acid positions may be more strongly associated than classical HLA associations; for example with anti-Jo-1 autoantibodies and position 74 of HLA-DRB1 (p=3.47×10^–64) and position 9 of HLA-B (p=7.03×10^–11). We report novel genetic associations with HLA-DQB1 anti-TIF1 autoantibodies and identify haplotypes that may differ between adult-onset and juvenile-onset patients with these autoantibodies.

Conclusions

These findings provide new insights regarding the functional consequences of genetic polymorphisms within the MHC. As autoantibodies in IIM correlate with specific clinical features of disease, understanding genetic risk underlying development of autoantibody profiles has implications for future research.

Autoimmune diseases and 8.1 ancestral haplotype: An update

The aim of the present review is to provide an update of the current research into the pathogenesis of autoimmune diseases associated with 8.1 ancestral haplotype. This is a common Caucasoid haplotype carried by most people who type for HLA-B8, DR3. Numerous genetic studies reported that individuals with certain HLA alleles have a higher risk of specific autoimmune disorders than those without these alleles. However, much remains to be learned about the heritability of autoimmune conditions. Recently, progress and advances in the field of genome-wide-association studies have revolutionized the capacity to perform large, economically feasible, and statistically robust analyses of HLA within 8.1 ancestral haplotype, and understand its contribute to autoimmune events. In this paper, the characteristic features of this haplotype that might give rise to diverse autoimmune phenotypes are reviewed, focusing on the contribution of the HLA-DRB1 gene, the most polymorphic sequence within the HLA II region.

What does it mean if a patient is positive for anti-Jo-1 in routine hospital practice? A retrospective nested case-control study

Background:  It is widely believed that patients bearing auto-antibodies to histidyl tRNA synthetase (anti-Jo-1) very likely have a connective tissue disease including myositis and interstitial lung disease.  The value of positive tests in low disease prevalence settings such as those tested in routine care is unknown.  We sought to determine the value of anti-Jo-1 auto-antibodies in routine practice. Methods: Our study was a nested case control study within a retrospective cohort of all patients tested for anti-ENA our hospital, from any hospital department, between January 2013 and December 2014.  Data was extracted from electronic records of anti-Jo-1 positive patients and randomly selected ENA negative patients (ratio of 1:2), allowing for a minimum follow up of at least 12 months after first testing. Results: 4009 samples (3581 patients) were tested.  Anti-ENA was positive in 616 (17.2%) patients, 40 (1.1%) were anti-Jo-1 positive. Repeat ENA testing was done for 350/3581 (9.8%) patients (428 of 4009 (10.7%) samples) and in 7/40 (17.5%) of anti-Jo-1 positive patients. The median interval between the first and second request was 124 days (inter-quartile range 233 days).  The frequencies of interstitial lung disease (ILD), myositis and Raynaud's were comparable for anti-Jo-1 positive patients (n=40) and 80 randomly selected ENA negative controls.  Positive tests led to additional diagnostic testing in the absence of clinical disease.  Sensitivity of Jo-1 for ILD was 50% (CI 19-81%), specificity 68% (CI 59-77%), positive predictive value 12.5% (CI 4 to 27%) and negative predictive value 93.8% (CI 86-98%). Of 10 (25%) patients with high anti-Jo1 levels, 3 had ILD, one myositis and two a malignancy (disseminated melanoma and CML).  Conclusion: Anti-Jo-1 is uncommon in a heterogenous hospital population and is only weakly predictive for ILD.  Repeated test requests were common and potentially unnecessary indicating that controls over repeat requests could yield significant cost savings.

The utility of comprehensive autoantibody testing to differentiate connective tissue disease associated and idiopathic interstitial lung disease subgroup cases

Interstitial lung disease (ILD) comprises many heterogeneous disease groups, the largest being CTD-associated and those labelled as idiopathic out of necessity. The mechanisms causing ILD are poorly understood, but most CTD- and idiopathic-ILD cases can respond to immunosuppression, clearly suggesting a pathological role for inflammation. By contrast, corticosteroid immunosuppression causes harm without benefit in the feared idiopathic pulmonary fibrosis, suggesting that inflammation plays little pathological role, and where ILD progresses rapidly to lethal outcome even with anti-fibrotic drug use. Given the treatment response differences apparent between ILD subgroups, and the dangers and costs of corticosteroid and anti-fibrotic drug use, respectively, it has become vital in every ILD patient to make an accurate subgroup diagnosis, to optimize treatment selections. This review discusses why differentiating CTD- and idiopathic-ILD subgroup cases remains so problematic, and why existing comprehensive CTD-specific serology would, if generally available, represent an ideal biomarker tool to enhance ILD subgroup diagnostic accuracy.

HLA-DRB1 Alleles as Genetic Risk Factors for the Development of Anti-MDA5 Antibodies in Patients with Dermatomyositis

Objective.

Patients with polymyositis/dermatomyositis (PM/DM) who express anti-melanoma differentiation associated protein 5 (anti-MDA5) antibodies frequently present with interstitial lung disease (ILD). The aim of this study was to investigate the association of HLA-DRB1 with anti-MDA5 expression in PM/DM.

Methods.

The frequency of DRB1 alleles was compared among 70 patients with PM, 104 patients with DM, and 400 healthy controls in a Han Chinese population.

Results.

Frequencies of DRB1*04:01 [17.0% vs 1.3%, corrected p value (pc) = 3.8 × 10−8, OR 16.2, 95% CI 6.6–39.7] and *12:02 (42.6% vs 19.3%, pc = 0.008, OR 3.1, 95% CI 1.7–5.7) were significantly higher in anti-MDA5–positive patients with PM/DM compared with the controls. The frequencies of DRB1*04:01 (p = 5.2 × 10−6, OR 17.1, 95% CI 5.3–54.9) and *12:02 (p = 3.8 × 10−4, OR 3.1, 95% CI 1.7–5.7) in anti-MDA5–positive patients with DM-ILD were higher than in the controls, whereas the frequencies of DRB1*04:01 and *12:02 did not differ between the anti-MDA5–negative patients with DM-ILD and controls. No difference in the frequency of DRB1 alleles, other than *04:01, carrying the “shared epitope” (SE), i.e., *01:01, *01:02, *04:05, and *10:01, was observed between the controls and patients with DM stratified by the presence of anti-MDA5 and ILD.

Conclusion.

DRB1*04:01 and *12:02 confer susceptibility to anti-MDA5 antibody production in DM, which cannot be explained by the SE hypothesis.

Pulmonary manifestations of rheumatologic diseases

PURPOSE OF REVIEW

The present review intends to provide an overview of the diversity and complexity of pulmonary manifestations of rheumatologic diseases and gaps in knowledge to effectively manage them.

RECENT FINDINGS

Diffuse lung disease in children with rheumatologic diseases represents a heterogeneous group of autoimmune disorders. Despite their significant morbidity and mortality, we have limited understanding about their pathogenesis. Here, we provide an overview of the pathophysiology and current management approach of these disorders, highlighting tools which assist with diagnosis, risk stratification and therapy. In this context, we address the need to develop a standardized approach to diagnose at-risk patients with rheumatologic disease and to predict their progression and the need to develop robust studies which evaluate the factors and interventions that influence pulmonary disease outcome.

SUMMARY

Diffuse lung disease in children with rheumatologic diseases represents a heterogeneous group of severe autoimmune disorders. By adopting a collaborative research approach among multicenters to help diagnose, risk stratify, and understand disease progression, effective management decisions can be optimized to improve clinical outcome.

Factors Associated with Interstitial Lung Disease in Patients with Polymyositis and Dermatomyositis: A Systematic Review and Meta-Analysis

OBJECTIVES

Interstitial lung disease (ILD) is an extramuscular manifestation that results in increased morbidity and mortality from polymyositis (PM) and dermatomyositis (DM). The aim of this study was to systematically evaluate risk factors associated with the development of ILD in PM/DM.

METHODS

Observational studies were identified from searching PubMed, Medline, Embase, and the Cochrane Library. Pooled odds ratios (ORs) or standardized mean differences (SMDs) and corresponding 95% confidence intervals (CIs) were obtained for the relationships between risk factors and ILD in PM/DM using either fixed- or random-effects models, whichever were appropriate. Heterogeneity tests, sensitivity analyses, and publication bias assessments were also performed.

RESULTS

Twenty-three studies were selected for a meta-analysis that included 834 patients and 1245 control subjects. Risk factors that may have increased the risk of developing ILD in PM/DM patients included older age at diagnosis (SMD, 0.35; 95% CI, 0.18-0.52; P < 0.0001), arthritis/arthralgia (OR, 3.17; 95% CI, 1.99-5.04; P < 0.00001), fever (OR, 2.31; 95% CI, 1.42-3.76; P = 0.0007), presence of anti-Jo-1 antibodies (OR, 3.34; 95% CI, 2.16-5.16; P < 0.00001), elevated erythrocyte sedimentation rate (ESR; SMD, 0.48; 95% CI, 0.32-0.64; P < 0.00001), presence of anti-MDA5 antibodies (OR, 18.26; 95% CI, 9.66-34.51; P < 0.00001), and elevated C-reactive protein level (CRP; OR, 3.50; 95% CI, 1.48-8.28; P = 0.004). Meanwhile, malignancy (OR, 0.36; 95% CI, 0.18-0.72; P = 0.004) reduced the risk of developing ILD in PM/DM patients.

CONCLUSION

Our meta-analysis results suggest that the association between PM/DM and ILD may be due to such risk factors as older age at diagnosis, arthritis/arthralgia, fever, presence of anti-Jo-1 antibodies, elevated ESR, presence of anti-MDA5 antibodies, and elevated CRP level, while malignancy was associated with a reduced risk of developing ILD. Thus, these variables may be used to guide screening processes for ILD in patients with PM/DM.

Variation at HLA-DPB1 is associated with dermatomyositis in Chinese population

Dermatomyositis (DM) is a polygenic disorder characterized by inflammation of skeletal muscle and skin. To date, the exact etiopathogenesis of DM remains elusive. To explore the genetic basis of DM, we conducted genome-wide genotyping analysis of 127 patients and 1566 healthy controls by Illumina Human OmniZhongHua-8 BeadChips in the Chinese Han population. We investigated whether the three SNP (rs7750458, rs9501251 and rs9500928) at 6p21.32 in the HLA-DPB1 gene were significantly associated with DM (P < 5 × 10^-8 ) and identified two susceptibility loci at 7q34 (PIP, rs9986765, P = 7.45 × 10^-7 , odds ratio [OR] = 2.71) and 10q24.2 (CPN1, rs3750716, P = 9.04 × 10^-7 , OR = 4.39) with suggestive evidence. We imputed 6674 classical human leukocyte antigen (HLA) alleles, amino acids and SNP from the discovery dataset, and stepwise analysis revealed that HLA-DPB1*17 in class II HLA genes were significantly associated with DM susceptibility. This study represents the first genome-wide association study (GWAS) of DM in the Chinese Han population. For the first time, HLA-DPB1 was found to be associated with DM in this population. Moreover, we identified two novel suggestive susceptibility loci (PIP and CPN1) and confirmed four previously reported genes (DMB, DQA1, DQB1 and DRB1) having potential associations with DM in the Chinese Han population. Our GWAS results in this population should provide important information regarding the genetic etiopathogenesis of DM and facilitate the development of new therapies for the treatment of DM and the prevention of DM progression.

Idiopathic inflammatory myopathies and the lung

Idiopathic inflammatory myositis (IIM) is a group of rare connective tissue diseases (CTDs) characterised by muscular and extramuscular signs, in which lung involvement is a challenging issue. Interstitial lung disease (ILD) is the hallmark of pulmonary involvement in IIM, and causes morbidity and mortality, resulting in an estimated excess mortality of 50% in some series. Except for inclusion body myositis, these extrapulmonary disorders are associated with the general and visceral involvement frequently found in other CTDs including fever, Raynaud's phenomenon, arthralgia, nonspecific cutaneous modifications and ILD, for which the prevalence is estimated to be up to 65%. Substantial heterogeneity exists within the spectrum of IIMs, and each condition is associated with various frequencies and subtypes of pulmonary involvement. This heterogeneity is partly related to the presence of various autoantibodies encompassing anti-synthetase, anti-MDA5 and anti-PM/Scl. ILD is present in all subsets of IIM including juvenile myositis, but is more frequent in dermatomyositis and overlap myositis. IIM can also be associated with other presentations of respiratory involvement, namely pulmonary arterial hypertension, pleural disease, infections, drug-induced toxicity, malignancy and respiratory muscle weakness. Here, we critically review the current knowledge about adult and juvenile myositis-associated lung disease with a detailed description of therapeutics for chronic and rapidly progressive ILD.

Genome-wide association study identifies HLA 8.1 ancestral haplotype alleles as major genetic risk factors for myositis phenotypes

Autoimmune muscle diseases (myositis) comprise a group of complex phenotypes influenced by genetic and environmental factors. To identify genetic risk factors in patients of European ancestry, we conducted a genome-wide association study (GWAS) of the major myositis phenotypes in a total of 1710 cases, which included 705 adult dermatomyositis, 473 juvenile dermatomyositis, 532 polymyositis and 202 adult dermatomyositis, juvenile dermatomyositis or polymyositis patients with anti-histidyl-tRNA synthetase (anti-Jo-1) autoantibodies, and compared them with 4724 controls. Single-nucleotide polymorphisms showing strong associations (P<5×10(-8)) in GWAS were identified in the major histocompatibility complex (MHC) region for all myositis phenotypes together, as well as for the four clinical and autoantibody phenotypes studied separately. Imputation and regression analyses found that alleles comprising the human leukocyte antigen (HLA) 8.1 ancestral haplotype (AH8.1) defined essentially all the genetic risk in the phenotypes studied. Although the HLA DRB1*03:01 allele showed slightly stronger associations with adult and juvenile dermatomyositis, and HLA B*08:01 with polymyositis and anti-Jo-1 autoantibody-positive myositis, multiple alleles of AH8.1 were required for the full risk effects. Our findings establish that alleles of the AH8.1 comprise the primary genetic risk factors associated with the major myositis phenotypes in geographically diverse Caucasian populations.

Strategies for evaluating idiopathic inflammatory myopathy disease susceptibility genes

This review outlines the progress that has been made in understanding the genetics of the idiopathic inflammatory myopathies in the previous 2 years, with a particular focus on dermatomyositis and polymyositis. A recent genome-wide association study in dermatomyositis has confirmed the importance of the major histocompatibility region in this disease, and has suggested a shared genetic etiology with other autoimmune disorders. This has led to an ongoing study of additional immune-related loci using the Immunochip array. Candidate gene studies have identified novel risk associations in non-Europeans, such as STAT4 and HLA-DRB1 in the Japanese population. Evidence for gene-environment interactions has come from two recent studies implicating smoking status and statin use with HLA alleles. This review also touches on future approaches to genetic research in myositis, including bioinformatics tools to identify causal variants, HLA imputation from existing genetic data and statistical methods to investigate shared effects between subgroups of myositis.

Genetics of Interstitial Lung Disease: Vol de Nuit (Night Flight)

Interstitial lung disease (ILD) is a chronic, progressive fibrotic lung disease with a dismal prognosis. ILD of unknown etiology is referred to as idiopathic interstitial pneumonia (IIP), which is sporadic in the majority of cases. ILD is frequently accompanied by rheumatoid arthritis (RA), systemic sclerosis (SSc), polymyositis/dermatomyositis (PM/DM), and other autoimmune diseases, and is referred to as collagen vascular disease-associated ILD (CVD-ILD). Susceptibility to ILD is influenced by genetic and environmental factors. Recent advances in radiographic imaging techniques such as high-resolution computed tomography (CT) scanning as well as high-throughput genomic analyses have provided insights into the genetics of ILD. These studies have repeatedly revealed an association between IIP (sporadic and familial) and a single nucleotide polymorphism (SNP) in the promoter region of the mucin 5B (MUC5B). HLA-DRB1*11 alleles have been reported to correlate with ILD in European patients with SSc, whereas in Japanese patients with RA, the HLA-DR2 serological group was identified. The aim of this review is to describe the genetic background of sporadic IIP, CVD-ILD, drug-induced-ILD (DI-ILD), pneumoconiosis, and hypersensitivity pneumonitis. The genetics of ILD is still in progress. However, this information will enhance the understanding of the pathogenesis of ILD and aid the identification of novel therapeutic targets for personalized medicine in future.

Myositis registries and biorepositories: powerful tools to advance clinical, epidemiologic and pathogenic research

PURPOSE OF REVIEW

Clinical registries and biorepositories have proven extremely useful in many studies of diseases, especially rare diseases. Given their rarity and diversity, the idiopathic inflammatory myopathies, or myositis syndromes, have benefited from individual researchers' collections of cohorts of patients. Major efforts are being made to establish large registries and biorepositories that will allow many additional studies to be performed that were not possible before. Here, we describe the registries developed by investigators and patient support groups that are currently available for collaborative research purposes.

RECENT FINDINGS

We have identified 46 myositis research registries, including many with biorepositories, which have been developed for a wide variety of purposes and have resulted in great advances in understanding the range of phenotypes, clinical presentations, risk factors, pathogenic mechanisms, outcome assessment, therapeutic responses, and prognoses. These are now available for collaborative use to undertake additional studies. Two myositis patient registries have been developed for research, and myositis patient support groups maintain demographic registries with large numbers of patients available to be contacted for potential research participation.

SUMMARY

Investigator-initiated myositis research registries and biorepositories have proven extremely useful in understanding many aspects of these rare and diverse autoimmune diseases. These registries and biorepositories, in addition to those developed by myositis patient support groups, deserve continued support to maintain the momentum in this field as they offer major opportunities to improve understanding of the pathogenesis and treatment of these diseases in cost-effective ways.

HLA class II alleles may influence susceptibility to adult dermatomyositis and polymyositis in a Han Chinese population

Background

Polymyositis (PM) and dermatomyositis (DM) are idiopathic inflammatory myopathies. Genetic variability in human leukocyte antigen (HLA) genes plays an important role in the pathogenesis of PM and DM. However, few studies on the subject in Chinese populations have been reported thus far.

Methods

We studied the influence of HLA polymorphisms on DM and PM susceptibility by analyzing HLA-DRB1, HLA-DQA1, and HLA-DQB1 alleles in 71 adult DM patients, 20 adult PM patients, and 113 controls in a Han Chinese population.

Results

A positive association was found between HLA-DQA1*0104 and DM (p = 0.01; corrected p (p_corr) NS; odds ratio (OR) = 2.58; 95% confidence interval (CI): 1.18–5.64), while an inverse correlation was noted between HLA-DQB1*0303 and myositis patients with interstitial lung inflammation (p = 0.01; p_corr NS; OR = 0.25; 95% CI: 0.07–0.73). A positive relationship was also observed between HLA-DRB1*07 and DM (p = 0.01; p_corr NS; OR = 2.26; 95% CI: 1.12–4.59), while HLA-DRB1*03 seems to be protective against DM (p = 0.01; p_corr NS; OR = 0.26; 95% CI: 0.06–0.81). The lung complication was closely associated with HLA-DRB1*04 (p = 0.01; p_corr NS; OR = 2.82; 95% CI: 1.15–6.76) and HLA-DRB1*12 (p = 0.02; p_corr NS; OR = 2.52; 95% CI: 1.02–6.07). The frequency of HLA-DRB1*07 was significantly higher among myositis patients with dysphagia than among controls (p = 0.01; p_corr NS; OR = 4.78; 95% CI: 1.03–24.42). The putative haplotype DRB1*07-DQA1*01-DQB1*02 was positively correlated with DM (p = 0.03; p_corr NS; OR = 2.90; 95% CI: 1.02–8.93) and the lung complication (p = 0.02; p_corr NS; OR = 3.45; 95% CI: 1.04–11.58).

Conclusions

Our results demonstrate that HLA alleles may be involved in susceptibility to adult DM and PM in the Han Chinese population.

Clinical heterogeneity and outcomes of antisynthetase syndrome

The autoimmune connective tissue disease antisynthetase syndrome (ASS) is an inflammatory myopathy associated with myositis-specific autoantibodies, e.g. anti-tRNA-synthetase antibodies (ASA). Since 1976 eight different ASA have been rigorously identified, of which anti-hystidyl-tRNA synthetase (anti-Jo1) is the most prevalent. Other phenotype features of ASS include interstitial lung disease (ILD), Raynaud's phenomenon, polyarthritis, fever, and mechanic's hands. The clinical presentation of ASS varies greatly, as does the severity of involvement of different organs-both among patients and/or over the course of the disease. ILD has been associated with poor outcomes, but in general the heterogeneity of ASS prevents identification of robust prognosis indicators. Early identification of patients requiring aggressive immunosuppressive treatment is very challenging, and there are very few prospective trials available to help match treatment management to ASS clinical characteristics. This review will focus on the biological, clinical, functional, and morphological features of ASS associated with patient outcome. Our objective is to use compiled data on these subjects to discuss the usefulness of patient stratification in developing future prospective therapeutic trials.

Utility of anti-melanoma differentiation-associated gene 5 antibody measurement in identifying patients with dermatomyositis and a high risk for developing rapidly progressive interstitial lung disease: a review of the literature and a meta-analysis

OBJECTIVE

To assess the utility of anti-melanoma differentiation-associated gene 5 (anti-MDA5) antibody measurement for predicting a risk for developing rapidly progressive interstitial lung disease (RP-ILD) in patients with polymyositis/dermatomyositis (PM/DM).

METHODS

A single-center cohort of 64 consecutive Chinese patients with PM/DM was examined. Serum anti-MDA5 antibody was measured by enzyme-linked immunosorbent assay. For meta-analysis, we searched PubMed and the Institute for Scientific Information Web of Knowledge for original studies that measured anti-MDA5 antibodies in patients with PM/DM. We calculated pooled sensitivity, specificity, diagnostic odds ratio (DOR), and the summary receiver operating characteristic (sROC) curve.

RESULTS

In Chinese patients, anti-MDA5 antibodies were detected in 26 patients with classic DM or clinically amyopathic DM (CADM). Compared with anti-MDA5-negative patients, anti-MDA5-positive patients showed a higher prevalence of RP-ILD (P = 0.001). In a total of 233 patients with anti-MDA5 antibody, derived from 16 studies, a higher frequency of CADM was found in Japanese than in non-Japanese patients (74.7% versus 39.2%; P = 1.2 × 10(-7) ). Meta-analysis revealed that the pooled sensitivity and specificity of anti-MDA5 antibody for RP-ILD was 77% (95% confidence interval [95% CI] 64-87%) and 86% (95% CI 79-90%), respectively. The pooled DOR was 20.41 (95% CI 9.02-46.20) with a favorable area under the sROC curve of 0.89 (95% CI 0.63-0.98).

CONCLUSION

Detection of anti-MDA5 antibody is a valuable tool for identifying DM patients with a high risk for developing RP-ILD, but the distribution of classic DM and CADM in patients with this antibody varies among ethnic groups.

[Clinical phenotypes and prognosis of antisynthetase syndrome]

Antisynthetase syndrome (ASS) was first described in 1989 as an inflammatory myopathy associated with the presence of specific auto-antibodies, namely the anti-tRNA-synthetase antibodies (ASA). To date, the ASA family comprises eight different auto-antibodies, among which anti-hystidyl-tRNA-synthetase (anti-Jo1) is the most prevalent. In addition to myositis, a constellation of clinical features has also been described in ASS, including interstitial lung disease, Raynaud's phenomenon, polyarthritis, fever and mechanic's hands. Large variations in the distribution and the severity of each of these symptoms are reported from one patient to another, and also over the course of the disease. The heterogeneity of this autoimmune connective tissue disease has led to difficulties in the early identification of patients with a poor outcome (those who will require the most intensive treatments). Additionally, very few prospective trials have so far compared the efficacy of the different immunosuppressive drugs available, and evidence is lacking to help adapting therapeutic strategies to all of the different ASS clinical situations. We will review the different characteristics of ASS (namely biological, clinical, functional, and morphological ASS parameters) that have recently been shown to correlate with patients' outcome, our aim being to discuss the usefulness of patient stratification for elaborating targeted therapeutic trials for ASS in the future.

Myositis-specific and myositis-associated autoantibody profiles and their clinical associations in a large series of patients with polymyositis and dermatomyositis

OBJECTIVE

To analyze the prevalence of myositis-specific and myositis-associated autoantibodies and their clinical correlations in a large series of patients with dermatomyositis/polymyositis.

METHOD

This cross-sectional study enrolled 127 dermatomyositis cases and 95 polymyositis cases. The disease-related autoantibody profiles were determined using a commercially available blood testing kit.

RESULTS

The prevalence of myositis-specific autoantibodies in all 222 patients was 34.4%, whereas myositis-associated autoantibodies were found in 41.4% of the patients. The most frequently found autoantibody was anti-Ro-52 (36.9%), followed by anti-Jo-1 (18.9%), anti-Mi-2 (8.1%), anti-Ku (4.1%), anti-SRP (3.2%), anti-PL-7 (3.2%), anti-PL-12 (2.7%), anti-PM/Scl75 (2.7%), and anti-PM/Scl100 (2.7%). The distributions of these autoantibodies were comparable between polymyositis and dermatomyositis, except for a higher prevalence of anti-Jo-1 in polymyositis. Anti-Mi-2 was more prevalent in dermatomyositis. Notably, in the multivariate analysis, anti-Mi-2 and anti-Ro-52 were associated with photosensitivity and pulmonary disorders, respectively, in dermatomyositis. Anti-Jo-1 was significantly correlated with pulmonary disorders in polymyositis. Moreover, anti-Ro-52 was associated with anti-Jo-1 in both diseases. No significant correlation was observed between the remaining autoantibodies and the clinical and/or laboratory findings.

CONCLUSIONS

Our data are consistent with those from other published studies involving other populations, although certain findings warrant consideration. Anti-Ro-52 and anti-Jo-1 were strongly associated with one another. Anti-Ro-52 was correlated with pulmonary disorders in dermatomyositis, whereas anti-Jo-1 was correlated with pulmonary alterations in polymyositis.

Pulmonary hypertension in parenchymal lung disease

Idiopathic pulmonary arterial hypertension (IPAH) has been extensively investigated, although it represents a less common form of the pulmonary hypertension (PH) family, as shown by international registries. Interestingly, in types of PH that are encountered in parenchymal lung diseases such as interstitial lung diseases (ILDs), chronic obstructive pulmonary disease (COPD), and many other diffuse parenchymal lung diseases, some of which are very common, the available data is limited. In this paper, we try to browse in the latest available data regarding the occurrence, pathogenesis, and treatment of PH in chronic parenchymal lung diseases.