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Objectives In order to address the reliability of commercial assays to identify myositis-specific and -associated autoantibodies, we aimed to compare the results of two commercial immunoassays with the results obtained by protein immunoprecipitation. Methods Autoantibody status was determined using radio-labelled protein immunoprecipitation for patients referred to our laboratory for myositis autoantibody characterization. For each autoantibody of interest, the sera from 25 different patients were analysed by line blot (Euroline Myositis Antigen Profile 4, EuroImmun, Lübeck, Germany) and dot blot (D-Tek BlueDiver, Diagnostic Technology, Belrose, NSW, Australia). Sera from 134 adult healthy controls were analysed. Results Overall commercial assays performed reasonably well, with high agreement (Cohen’s κ >0.8). Notable exceptions were the detection of rarer anti-synthetases with κ Conclusion The assays analysed do not perform well for all myositis-specific and -associated autoantibodies and overall false positives are relatively common. It is crucial that clinicians are aware of the limitations of the methods used by their local laboratory. Results must be interpreted within the clinical context and immunoprecipitation should still be considered in selected cases, such as apparently autoantibody-negative patients where anti-synthetase syndrome is suspected.

Objectives To describe the prevalence and clinical associations of autoantibodies to a novel autoantigen, eukaryotic initiation factor 3 (eIF3), detected in idiopathic inflammatory myositis. Methods Sera or plasma from 678 PM patients were analysed for autoantigen specificity by radio-labelled protein immunoprecipitation (IPP). Samples immunoprecipitating the same novel autoantigens were further analysed by indirect immunofluorescence and IPP using pre-depleted cell extracts. The autoantigen was identified through a combination of IPP and MALDI-TOF mass spectrometry, and confirmed using commercial antibodies and IPP-western blots. Additional samples from patients with DM (668), DM-overlap (80), PM-overlap (191), systemic sclerosis (150), systemic lupus erythematosus (200), Sjogren’s syndrome (40), rheumatoid arthritis (50) and healthy controls (150) were serotyped by IPP as disease or healthy controls. Results IPP revealed a novel pattern in three PM patients (0.44%) that was not found in disease-specific or healthy control sera. Indirect immunofluorescence demonstrated a fine cytoplasmic speckled pattern for all positive patients. Mass spectrometry analysis of the protein complex identified the target autoantigen as eIF3, a cytoplasmic complex with a role in the initiation of translation. Findings were confirmed by IPP-Western blotting. The three anti-eIF3-positive patients had no history of malignancy or interstitial lung disease, and had a favourable response to treatment. Conclusion We report a novel autoantibody in 0.44% of PM patients directed against a cytoplasmic complex of proteins identified as eIF3. Although our findings need further confirmation, anti-eIF3 appears to correlate with a good prognosis and a favourable response to treatment.

Objectives It has been over 10 years since the first report of autoantibodies directed against phenylalanyl tRNA synthetase (anti-Zo) in a patient with features of the anti-synthetase syndrome. In that time no further cases have been published. Here we aim to characterize more fully the clinical phenotype of anti-Zo–associated myositis by describing the clinical features of nine patients. Methods Anti-Zo was identified by protein-immunoprecipitation in patients referred for extended spectrum myositis autoantibody testing at our laboratory. Results were confirmed by immunodepletion using a reference serum. Medical records were retrospectively reviewed to provide detailed information of the associated clinical phenotype for all identified patients. Where possible, HLA genotype was imputed using Illumina protocols. Results Nine patients with anti-Zo were identified. The median age at disease onset was 51 years, and six patients were female. Seven patients had evidence of inflammatory muscle disease, seven of interstitial lung disease and six of arthritis. The reported pattern of interstitial lung disease varied with usual interstitial pneumonia, non-specific interstitial pneumonia and organizing pneumonia all described. Other features of the anti-synthetase syndrome such as RP and mechanics hands were common. HLA data was available for three patients, all of whom had at least one copy of the HLA 8.1 ancestral haplotype. Conclusion Patients with anti-Zo presenting with features of the anti-synthetase syndrome and interstitial lung disease is a common finding. Like other myositis autoantibodies, there is likely to be a genetic association with the HLA 8.1 ancestral haplotype.

Myositis autoantibodies can help subset patients into more homologous groups, aiding in diagnosis and helping to predict potential disease complications. In recent years, a number of novel myositis autoantibodies including anti-HMGCR, anti-SAE, anti-CN1A and anti-PUF60 have been identified and characterised, with the majority of myositis patients now having a detectable autoantibody. Preliminary studies have also led to the discovery of a number of emerging myositis autoantibodies including anti-SMN, anti-cortactin, anti-NPC and anti-FHL1, which when fully characterised may provide additional insight into disease pathogenesis as well as providing additional subsets in the serological classification of myositis. This chapter describes the prevalence and clinical associations of these new and emerging biomarkers.

Background The close temporal association between onset of some connective tissue diseases and cancer suggests a paraneoplastic association. Adult patients with scleroderma with anti-RNA polymerase III autoantibodies and adult patients with dermatomyositis with anti-transcriptional intermediary factor 1 (anti-TIF1) or anti-nuclear matrix protein 2 (anti-NXP2) autoantibodies have a significantly increased risk of developing cancer. Autoantibodies may serve as biomarkers for early detection of cancer and also could be relevant for prediction of responses to immune therapies. We aimed to test whether myositis and scleroderma specific or associated autoantibodies are detectable in individuals with lung cancer. Methods Serum from 60 Caucasian patients with lung cancer (30 with small cell lung cancer, 30 with non-small cell lung cancer) was screened for myositis and scleroderma specific and associated autoantibodies by radiolabelled immunoprecipitation. Results Anti-TIF1, anti-NXP2 or anti-RNA polymerase III autoantibodies were not detected in any of the 60 patients with lung cancer. Anti-glycyl-transfer RNA (tRNA) synthetase (anti-EJ) autoantibodies were detected in one patient with non-small cell lung cancer. No other known myositis or scleroderma autoantibodies were identified. Conclusions Myositis and scleroderma specific autoantibodies, including anti-TIF1, anti-NXP2 and anti-RNA polymerase III, are rare in patients with lung cancer without an autoimmune disease. We report here the first case of anti-EJ autoantibodies being detected in a patient with lung cancer without clinical or radiographic evidence of the anti-synthetase syndrome. Electronic supplementary material The online version of this article (10.1186/s13075-018-1678-9) contains supplementary material, which is available to authorized users.

Objectives: Autoantibodies targeting ubiquitously expressed nuclear antigens can be identified in most patients with SSc. Cytoplasmic autoantibodies (in otherwise ANA-negative sera) targeting eukaryotic initiation factor-2B (anti-eIF2B) have recently been identified in SSc with clinical associations to dcSSc disease and interstitial lung disease (ILD), although the majority of samples originated from a tertiary SSc-ILD centre. We investigated the prevalence and clinical associations of recently described SSc-specific (including anti-eIF2B) and other cytoplasmic autoantibodies in ANA-negative sera obtained from a large representative SSc cohort.Methods: ANA-negative sera from the Scleroderma Family Registry and DNA Repository underwent indirect immunofluorescence, radiolabelled protein immunoprecipitation (± immunodepletion) to identify anti-eIF2B and other CTD-related autoantibodies. The clinical phenotype of positive samples was evaluated.Results: Immunoprecipitation was performed on 128 ANA-negative samples (obtained from 3249 SSc patients). Anti-eIF2B antibodies were present in nine patients (7%), the majority of whom had dcSSc (8/9). SSc-ILD was present in all anti-eIF2B patients for whom chest imaging was available (7/9). Anti-synthetase autoantibodies (targeting PL12, PL7, OJ and Zo) were identified in seven patients (5.5%), all of whom fulfilled the 2013 ACR/EULAR classification criteria for SSc and had evidence of SSc-ILD where relevant outcomes were available for evaluation. Anti-RuvBL1/2 antibodies were identified in two patients with SSc-overlap syndromes.Conclusion: Anti-eIF2B antibodies are cytoplasmic SSc-specific autoantibodies with strong clinical associations with dcSSc and SSc-ILD found in ANA-negative sera. Anti-synthetase autoantibodies, and other recently discovered SSc-specific antibodies such as anti-RuvBL1/2, can also be identified in ANA-negative SSc.

Background:Since first described, our understanding of polymyositis (PM) has evolved substantially. Patients previously diagnosed with PM may now be better described as having an alternative diagnosis, including immune-mediated necrotizing myopathy (IMNM), connective tissue disease overlap myositis (CTD-OM), anti-synthetase syndrome (ASS) or inclusion body myositis (IBM).Objectives:To apply the current understanding of IIM subtypes to retrospectively review the diagnosis of patients classified as PM at our centre.Methods:We reviewed a cohort of 255 patients from a UK tertiary myositis clinic, with 37 patients classified as PM according to the EULAR/ACR IIM criteria and expert opinion (1). Consensus decisions made as to whether reclassification as an alternative IIM subtype would be appropriate in each case.Results:Thirty-seven patients with PM diagnosis according to EULAR/ACR IIM criteria and expert opinion were included in the analysis. Twenty-six patients (26/37, 68.4%) were female. The mean age at diagnosis was 57 years (SD 16.25) and mean follow up was 5.2 years (SD 4.8).After consensus discussions, ten patients (27%) retained classification as PM, representing 3.9% (10/255) of the original cohort of 255 patients. The remaining 27 were reclassified as follows: 7 CTD-OM (18.9%), 6 IMNM (16.2%), 6 unspecified myopathy (16.2%), 2 DM (5.4%), 1 IBM (2.7%), and 1 non-inflammatory myopathy (2.7%, myofibrillar myopathy). Four patients (10%) had insufficient data available to allow for a defined diagnosis.Of the 10 patients retaining classification as PM, 7 (70%) were female and mean age at diagnosis was 58.9 years. Clinical characteristics are represented in table 1. Mean CK at diagnosis was 2321 IU/L. Four patients (40%) were ANA positive, 8 patients (80%) were tested for the complete myositis antibody panel and 8 (80%) were specifically tested for the presence of HMGCR antibodies (figure 1). EMG revealed a myopathic pattern in 6/7 patients tested, while MRI demonstrated muscle oedema compatible with myositis in 3/5 of the patients that were tested. A complete muscle biopsy report was available in 8/10 PM-classified patients (80%), diffuse HLA-1 upregulation was present in 5 patients (50%), endomysial inflammatory infiltrates in 5 (50%) and perimysial infiltrates (in conjunction with endomysial infiltrates) in 3 (30%). No other specific features were found.Table 1.Clinical features.PM (n=10)CTD-OM (n=7)IMNM (n=6)All (n=37)Pyrexia0001 (2.7 %)Weight loss2 (20%)2 (28.6%)2 (33.3%)6 (16.2 %)Cutaneous rash01 (14.3%)02 (5.4 %)Mechanic’s hands1 (10%)2 (28.6%)04 (10.8 %)Sclerodactyly01 (14.3%)01 (2.7 %)Periungual erythema01 (14.3%)02 (5.3 %)Raynaud’s05 (71.4%)08 (21.6 %)Arthralgia05 (71.4%)08 (21.6 %)Arthritis02 (28.6%)05 (13.5 %)Muscle weakness10 (100%)7 (100%)6 (100%)36 (97.2%)Myalgia3 (30%)5 (71.4%)3 (50%)20 (54 %)Dysphagia3 (30%)5 (71.4%)1 (16.7%)13 (35.1 %)Interstitial lung disease (ILD)03 (42.9%)04 (10.5 %)Malignancy1 (9.1%)02 (33.3%)3 (8.1%)Conclusion:This study confirms that PM can now be considered a rare IIM subtype. A thorough examination, complete myositis antibody panel including HMGCR testing and careful interpretation of the biopsy results is recommended to accurately classify these patients.References:[1]Parker MJS, Oldroyd A, Roberts ME, Lilleker JB, Betteridge ZE, McHugh NJ, et al. The performance of the European League Against Rheumatism/American College of Rheumatology idiopathic inflammatory myopathies classification criteria in an expert-defined 10 year incident cohort. Rheumatol (United Kingdom). 2019 Mar 1;58(3):468–75Disclosure of Interests:None declared

Objectives To characterise the 10 year relationship between anti-transcriptional intermediary factor 1 antibody (anti-TIF1-Ab) positivity and cancer onset in a large UK-based adult dermatomyositis (DM) cohort. Methods Data from anti-TIF1-Ab positive/negative adults with verified diagnoses of DM from UKMYONET were analysed. Each patient was followed up until they developed cancer. Kaplan-Meier methods and Cox-proportional hazard modelling were employed to estimate cumulative cancer incidence. Results Data from 263 DM cases were analysed, with a total of 3,252 person-years and a median 11 years follow-up; 55 (21%) of DM cases were anti-TIF1-Ab positive. After 10 years of follow up, a higher proportion of anti-TIF1-Ab positive cases developed cancer, compared with anti-TIF1-Ab negative cases: 38% vs 15% (hazard ratio 3.4 [95% CI 2.2, 5.4]). All the detected malignancy cases in the anti-TIF1-Ab positive cohort occurred between 3 years prior to and 2.5 years after DM onset. No cancer cases were detected within the following 7.5 years in this group, whereas cancers were detected during this period in the anti-TIF1-Ab negative cases. Ovarian cancer was more common in the anti-TIF1-Ab positive vs negative cohort – 19% versus 2% respectively (p-value

ObjectivesIdiopathic 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.MethodsWe 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.ResultsWe report associations with eight autoantibodies reaching our study-wide significance level of p–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.ConclusionsThese 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.

Objectives To determine prevalence and co-existence of myositis specific autoantibodies (MSAs) and myositis associated autoantibodies (MAAs) and associated clinical characteristics in a large cohort of idiopathic inflammatory myopathy (IIM) patients. Methods Adult patients with confirmed IIM recruited to the EuroMyositis registry (n = 1637) from four centres were investigated for the presence of MSAs/MAAs by radiolabelled-immunoprecipitation, with confirmation of anti-MDA5 and anti-NXP2 by ELISA. Clinical associations for each autoantibody were calculated for 1483 patients with a single or no known autoantibody by global linear regression modelling. Results MSAs/MAAs were found in 61.5% of patients, with 84.7% of autoantibody positive patients having a sole specificity, and only three cases (0.2%) having more than one MSA. The most frequently detected autoantibody was anti-Jo-1 (18.7%), with a further 21 specificities each found in 0.2–7.9% of patients. Autoantibodies to Mi-2, SAE, TIF1, NXP2, MDA5, PMScl and the non-Jo-1 tRNA-synthetases were strongly associated (p, Highlights • Myositis specific autoantibodies very rarely coexist in the one individual allowing endotypes to be more precisely defined. • The association of anti-TIF1 and cancer-associated myositis is confirmed with a cut-off age of over 58 years. • In a large combined European myositis cohort associations of anti-SRP with carditis and anti-Mi-2 with cancer have emerged. • Myositis associated autoantibodies are strongly associated with having myositis in association with another connective tissue disease.

Introduction ILD represents a heterogeneous spectrum of subgroups, the biggest being IPF and connective tissue disease ILD (CTD-ILD). In IPF, a lack of biomarkers and the dangers of lung biopsy make the diagnosis dependant on HRCT. Usual Interstitial Pneumonia changes are typical of IPF, but can also occur in CTD-ILD, making misdiagnosis a possibility. While CTD-ILDs can respond to immunosuppression with corticosteroids and disease modifying drugs, these agents are ineffective and harmful in IPF, and therefore contraindicated (Raghu et al. N Eng J Med 2012; 366: 1968). Where possible, it is thus important to exclude a covert CTD-ILD in IPF patients. Previous studies have detected autoantibodies in 6%–38% of patients with idiopathic interstitial pneumonias (Song et al. Yonsei Med J 2015; 56: 676, Watanabe et al. Respir Med 2011; 105: 1238), but wide-ranging CTD serotyping has not been undertaken in a large UK IPF cohort. Methods The gold standard for autoantibody detection is immunoprecipitation (IP), which very occasionally detects anti-Ro, but no other, autoantibodies in normal subjects. IP of radio-labelled K562 cells was used to serotype 250 IPF patients recruited via UK-BILD. All satisfied the 2011 ATS/ERS diagnostic guidelines and had IPF-specific HRCT changes (Raghu et al. Am J Respir Crit Care Med 2011; 183: 788). Proteins recognised by autoantibodies from patients’ serum were fractionated by 9% SDS-PAGE gel, and identified by autoradiography. Known autoantigens were identified by direct comparison with antibody positive controls on the same gel. Results Four of 250 IPF patients (1.6%) were IP-positive for recognised CTD-specific autoantibodies, including one with an anti-synthetase (anti-OJ) and three with scleroderma or scleromyositis overlap-associated antibodies (anti-RNA Polymerase II, anti-PM-Scl and anti-Ku respectively). There were no clinical or radiographic characteristics which distinguished antibody positive from antibody negative cases. Conclusion Although CTD-specific autoantibodies were detected in only a tiny proportion of IPF patients, to suggest a possible misdiagnosis, this could have potentially serious therapeutic implications for individual patients. We recommend that, while IPF is clearly a robust diagnosis when made by multidisciplinary teams in tertiary centres, clinicians should endeavour to undertake comprehensive autoantibody testing in all IPF cases.

Objective Anti-nuclear autoantibodies are known to occur in 85-99% of Systemic Sclerosis (SSc) patients, with each SSc autoantibody correlating with a distinct clinical subset of patients. The objective of this study was to investigate novel SSc autoantibodies in the remaining autoantibody negative patients and establish clinical associations. Methods Serum samples and clinical data were collected from 548 SSc patients. Sera were tested for known SSc autoantibodies by routine serological techniques, with negative samples being further investigated by radiolabelled protein immunoprecipitation (IPP). Sera that immunoprecipitated a novel 30 kDa band were analysed by indirect immunofluorescence and IPP using depleted cell extracts to establish a common reactivity. Mass spectrometry (MS) was used to identify the novel autoantigen and findings were confirmed using commercial antibodies. Sera from 426 patients with other forms of connective tissue disease, 103 patients with rheumatoid arthritis, 114 patients with idiopathic ILD and 150 healthy controls were serotyped as controls. Results A novel autoantigen with a molecular weight of ∼30 kDa was recognised by seven sera with SSc, six of whom had interstitial lung disease (ILD) and by no controls. Six of the patients had diffuse cutaneous involvement and four had overlap features with other autoimmune diseases. Immunodepletion experiments indicated that all samples targeted the same autoantigen and MS identified the novel autoantigen as eIF2B (Eukaryotic Initiation Factor 2B). Conclusion We report a novel autoantibody (anti-eIF2B) in a small number of patients with SSc (approximately 1%) that is closely associated with diffuse cutaneous manifestations and the presence of ILD. This article is protected by copyright. All rights reserved.

Myositis is a heterogeneous group of autoimmune diseases, with different pathogenic mechanisms contributing to the different subsets of disease. The aim of this study was to test whether the autoantibody profile in patients with myositis is associated with a type I interferon (IFN) signature, as in patients with systemic lupus erythematous (SLE). Patients with myositis were prospectively enrolled in the study and compared to healthy controls and to patients with SLE. Autoantibody status was analysed using an immunoassay system and immunoprecipitation. Type I IFN activity in whole blood was determined using direct gene expression analysis. Serum IFN-inducing activity was tested using peripheral blood cells from healthy donors. Blocking experiments were performed by neutralizing anti-IFNAR or anti-IFN-α antibodies. Patients were categorized into IFN high and IFN low based on an IFN score. Patients with autoantibodies against RNA-binding proteins had a higher IFN score compared to patients without these antibodies, and the IFN score was related to autoantibody multispecificity. Patients with dermatomyositis (DM) and inclusion body myositis (IBM) had a higher IFN score compared to the other subgroups. Serum type I IFN bioactivity was blocked by neutralizing anti-IFNAR or anti-IFN-α antibodies. To conclude, a high IFN score was not only associated with DM, as previously reported, and IBM, but also with autoantibody monospecificity against several RNA-binding proteins and with autoantibody multispecificity. These studies identify IFN-α in sera as a trigger for activation of the type I IFN pathway in peripheral blood and support IFN-α as a possible target for therapy in these patients.

Background:Overlap syndromes are autoimmune disorders in which classification criteria of at least two connective tissue diseases (CTDs) are fulfilled. The Division of Clinical Immunology in Debrecen, Hungary oversees patients with idiopathic inflammatory myopathies (IIMs) since the 1980’s.Objectives:In a work called The Myositis Antibody Research Project, which is coordinated together with the Bath Institute for Rheumatic Diseases (UK), authors investigated 330 patients with myositis, all treated in this Hungarian center.Methods:The aim of this retrospective study was to investigate the frequency, clinical and serological parameters and therapeutic options in myositis – rheumatoid arthritis overlap cases in this group of 330 patients.Results:The frequency of overlap cases, as seen in literature, was 13.64%. The importance of myositis-associated antibodies (MAAs) can be seen on this results: 44.44% of overlap patients, while only 7.02% of not overlap patients were MAA positive. Out of our 45 overlap patients twenty-seven myositis - RA overlap patients could be identified. Among these 27 patients the women:men ratio was 12.5:1, PM:DM ratio was 2.375:1. Muscle weakness and sceletal involvement was present in every patient, myalgia in 77.78% and Raynaud’s phenomenon in 48.15% of the patients; general symptoms during disease relapse (fatigue, weight loss, fever) were present in 59.26%, 18.52% and 14.82%, respectively. Ten cases had seropositive rheumatoid arthritis, with high titer of rheumatoid factor. Authors underline the importance of lung involvement as internal organ manifestation: 8 patients had anti-synthetase antibodies (six anti-Jo-1, one anti-PL-7 and one anti-PL-12). In anti-PL-7 and anti-PL-12 positive patients interstitial lung disease (ILD) appeared some years before myositis and early agressive management of ILD resulted in fast remission of muscle weakness. Anti-Mi-2 and anti-SRP could be detected in two patients. Most frequent used disease modifying antirheumatic drugs were cyclophosphamide, methotrexate and cyclosporine, 19 patients received DMARD combination therapy. Biological therapy was used in 3 patients, intravenous or subcutaneous immuneglobulin in 4 patients and one patient with RA – myositis – antiphospholipid syndrome died because of asipartion pneumonia.Conclusion:Authors conclude that it is really challenging to treat these overlap cases: they form a very heterogenous group of patients and management has to be personalized.Disclosure of Interests:None declared

OBJECTIVES: Immune-mediated necrotizing myopathy (IMNM) is characterized by the predominant presence of necrotic muscle fibres in muscle biopsy and variable response to immunosuppressive treatment. The aims of this study were to analyse the temporal trend of IMNM incidence in our centre over the past 10 years and to explore the role of statins as possible causative agents.METHODS: A retrospective evaluation of muscle biopsy results, clinical and laboratory data, including antibody associations of all patients with idiopathic inflammatory myopathy newly diagnosed between 2004 and June 2014, was performed. Available sera were tested for the presence of anti-3-hydroxy-3-methylglutaryl coenzyme A reductase (anti-HMGCR) autoantibodies.RESULTS: Of 357 biopsied patients, 233 fulfilled criteria for inflammatory/immune-mediated myopathy, including 27 (11.6%) classified as IMNM. There were no patients with IMNM diagnosed between 2004 and 2007; subsequently, two to three cases of IMNM per year were seen during the period 2008-11, with a substantial increase to 18 cases (66.6% of all IMNM biopsies) in 2012-14. Thirteen of 27 patients (48%) had a history of statin use, 11 (85%) of whom had positive anti-HMGCR antibodies. There was no IMNM patient without a history of statin use who was anti-HMGCR antibody positive.CONCLUSION: Our data show an increasing incidence of IMNM, which is mainly accounted for by anti-HMGCR-positive IMNM associated with the use of statins.

Background The idiopathic inflammatory myopathies (IIM) represent a rare and heterogeneous group of multisystem autoimmune diseases. The rarity of IIM has hampered research efforts, resulting in remarkably limited therapeutic evidence. The EuroMyositis Registry was created to pool resources and expertise across the international IIM research community. Objectives To describe the phenotypic characteristics of different IIM subtypes. Associations with malignancy, interstitial lung disease (ILD), cardiac involvement and dysphagia were assessed. Methods Pooled data from the EuroMyositis Registry (from Belgium, China, Czech Republic, Hungary, Italy, Mexico, Norway, Sweden, Switzerland, UK, Vietnam) were obtained. Associations were assessed using logistic regression and multinomial logistic regression with polymyositis (PM) as the reference group. Results Data regarding 3,196 patients were analysed. The UK was the largest contributor (n=1,307). The most common diagnoses were dermatomyositis (34%), PM (32%) and connective tissue disease (CTD)-overlap myositis (15%). In those with anti-synthetase syndrome (7%), 85% had muscle weakness, 86% ILD and 58% arthritis. Overall, 43% had a myositis specific antibody, most commonly anti-Jo1 autoantibodies (20%). Glucocorticoid usage was noted in 98%. Most commonly used disease modifying agents were methotrexate (71%) and azathioprine (50%). Malignancy occurred in 9% and was associated with a diagnosis of dermatomyositis (Relative Risk Ratio [RRR] 1.68, 95% CI 1.09–2.56, p=0.018). Cardiac involvement occurred in 9%, most commonly in those with CTD-overlap myositis (13%), and was associated with a higher Health Assessment Questionnaire disability index (1 versus 0.75, OR 1.40, 95% CI 1.03–1.91, p=0.031). Dysphagia occurred in 39% and was associated with a diagnosis of CTD-overlap myositis (RRR 2.25, 95% CI 1.61–3.15, p Conclusions This large international cohort demonstrates the heterogeneity of IIM and the burden of associated malignancy, ILD, cardiac and gastrointestinal involvement. The EuroMyositis Registry facilitates international collaborative research outputs, underlining the benefits of harmonised data collection methodology between centres. Acknowledgements This work was supported by researchers at the National Institute for Health Research (NIHR) Biomedical Research Unit. The views expressed are those of the authors and not necessarily those of the UK National Health Service, the NIHR or the UK Department of Health Disclosure of Interest J. Lilleker: None declared, J. Vencovsky: None declared, G. Wang: None declared, L. Wedderburn Grant/research support from: The UK JDM Cohort and Biomarker study is supported by grants from the NIHR and Myositis UK, L. Diederichsen: None declared, J. Schmidt: None declared, P. Jordan: None declared, O. Benveniste: None declared, M. G. Danieli: None declared, K. Dankό: None declared, N. T. P. Thuy: None declared, M. Vazquez-Del Mercado: None declared, O. Molberg: None declared, B. De Paepe: None declared, J. De Bleecker: None declared, B. Maurer Grant/research support from: AbbVie, Protagen, EMDO, Novartis, Roche, Actelion, N. Pipitone Speakers bureau: GRAPPA Workshop, Alfa-Wassermann, N. McHugh: None declared, Z. Betteridge: None declared, P. New: None declared, R. Cooper: None declared, W. Ollier: None declared, J. Lamb Grant/research support from: MedImmune, N. S. Krogh: None declared, I. Lundberg Grant/research support from: Astra-Zeneca, Bristol-Myers Squibb, Consultant for: Bristol-Myers Squibb, Idera, H. Chinoy Grant/research support from: MedImmune, Novartis

We thank Cavagna et al 1 for their thoughtful analysis relating to our recent publication.2 Several important points are raised, many of which we also referred to. It is of great interest and reassurance that the demographics and clinical features of antisynthetase syndrome (ASS) are broadly similar between the AENEAS (American and European NEtwork of Anti-Synthetase syndrome) and EuroMyositis cohorts. Clearly the frequency of interstitial lung disease and arthritis differs due to the sources of case ascertainment. This highlights …

Objective.We aimed to establish the prevalence and clinical associations of anti-HMG-CoA-reductase (anti-HMGCR) in a large UK cohort with juvenile myositis.Methods.There were 381 patients investigated for anti-HMGCR using ELISA.Results.Anti-HMGCR autoantibodies were detected in 4 patients (1%). These children had no or minimal rash and significant muscle disease. Muscle biopsies were considered distinctive, with widespread variation in fiber size, necrotic fibers, and chronic inflammatory cell infiltrates; all had prolonged elevation of creatine kinase and all ultimately received biologic therapies.Conclusion.Anti-HMGCR in UK children with myositis are associated with severe disease that is poorly responsive to standard treatment.

The purpose of this study is to review recent advances in the diagnostic utility of autoantibodies in dermatomyositis.Alternative nonspecialist testing methods have been developed for anti-transcription intermediary factor 1 gamma, anti-MDA5 and anti-nuclear matrix protein 2, which are potentially exploitable by any hospital laboratory. Although these have yet to be validated for diagnostic use, it is likely that testing for myositis-specific antibodies will soon become readily available.The identification of myositis-specific autoantibodies provides both diagnostic and prognostic information and offers a unique opportunity to adopt a stratified approach to treatment. Their identification, in many cases, should prevent the need for invasive diagnostic tests such as muscle biopsy.

Objective. Alterations in phenotype and function of endothelial progenitor cells (EPCs) have been associated with poor vascular outcomes and impaired vascular repair in various conditions. Our hypothesis was that patients with PM and DM have dysregulation of EPCs driven by type I IFN and IL-18 similar to other autoimmune diseases. Methods. Quantification of circulating EPCs was performed by flow cytometry in patients with PM/DM and matched healthy controls. The ability of EPCs to differentiate into mature endothelial cells was investigated by light and fluorescence microscopy quantification in the presence or absence of PM/DM or control serum, neutralizing antibodies to type I IFN receptor or IL-18. Serum type I IFN activity was quantified by induction of type I IFN-inducible genes in HeLa cells. Circulating IL-18 concentrations were assessed by ELISA. Results. Circulating EPCs were significantly lower in PM/DM patients compared with controls. PM/DM EPCs displayed a decreased capacity to differentiate into mature endothelial cells and PM/DM serum significantly inhibited differentiation of control EPCs. This effect was reversed in the majority of samples with neutralizing antibodies to IL-18 or to type I IFN receptor or by a combination of these antibodies. Patients with associated impairments in EPC function had higher type I IFN serum activity. Conclusion. PM/DM is associated with dysregulation of EPC phenotype and function that may be attributed, at least in part, to aberrant IL-18 and type I IFN pathways. The implication of these vasculopathic findings for disease prognosis and complications remains to be determined.

There is increasing evidence of autoimmunity in dermatomyositis and polymyositis, with strong correlations between particular myositis-specific autoantibodies (MSAs) and clinical subsets. It is now clear that corresponding autoantigens are selectively targeted, have distinct adjuvant properties and are upregulated in target tissues, suggesting a role in disease pathogenesis. This review highlights recent findings including the identification of novel MSAs and studies investigating autoantigen properties and expression in both target tissues and tumours.During the review period, the clinical associations of anti-SAE and anti-p140 have been further described. Studies of autoantigen expression have demonstrated upregulation of Mi-2 in response to ultraviolet (UV) damage and expression of myositis-specific autoantigens in rat newborn skeletal muscle. The role of type I interferon and adjuvant activity has also been highlighted through the identification of the CADM140 autoantigen as MDA5, a protein involved in innate immunity.There are now a number of models indicating roles of autoantigens in disease pathogenesis. Our increased understanding of the autoantigenic properties of these targeted proteins will help to determine the mechanisms involved in the initiation and propagation of myositis. In turn, these findings may lead to therapeutic advances including the development of more targeted treatments.

The idiopathic inflammatory myopathies (IIMs)--DM and PM--have been historically defined by broad clinical and pathological criteria. These conditions affect both adults and children with clinical features including muscle weakness, skin disease, internal organ involvement and an association with cancer in adults. Using a clinico-serological approach, DM and PM can be defined into more homogeneous subsets. Over the last few years, myositis-specific autoantibodies (MSAs) have been better characterized including autoantibodies directed against the aminoacyl tRNA-synthetase enzymes, the signal-recognition particle and the Mi-2 protein. In addition, clinically significant novel autoantibodies--anti-CADM-140, anti-SAE (small ubiquitin-like modifier activating enzyme), anti-p155/140 and anti-p140--have been described in the adult and juvenile disease spectrum. MSAs are directed against cytoplasmic or nuclear components involved in key regulatory intracellular processes including protein synthesis, translocation and gene transcription. The striking association between unique serological profiles and distinct clinical phenotypes suggests that target autoantigens may play a role in disease induction and propagation. In this review, we discuss the clinical utility and pathogenic significance of MSAs in disease expression.

Introduction: Myositis is an autoimmune disease characterised by proximal muscle weakness. Aim: The aim of the authors was to determine the frequency of dermatomyositis-specific autoantibodies (anti-Mi-2, anti-transcriptional intermediary factor 1 gamma, anti-nuclear matrix protein 2, anti-small ubiquitin-like modifier activating enzyme, anti-melanoma differentiation-associated gene) in a Hungarian myositis population and to compare the clinical features with the characteristics of patients without myositis-specific antibodies. Method: Antibodies were detected using immunoblot and immunoprecipitation. Results: Of the 330 patients with nyositis, 48 patients showed dermatomyositis-specific antibody positivity. The frequency of antibodies in these patients was lower than those published in literature Retrospective analysis of clinical findings and medical history revealed that patients with dermatomyositis-specific autoantibody had more severe muscle weakness and severe skin lesions at the beginning of the disease. Conclusions: Antibodies seem to be useful markers for distinct clinical subsets, for predicting the prognosis of myositis and the effectiveness of the therapy. Orv. Hetil., 2015, 156(36), 1451–1459.

Idiopathic inflammatory myopathies are systemic autoimmune diseases characterized by progressive proximal muscle weakness. Cancer-associated myositis represents the worst prognostic group within this heterogeneous disease.The aim of this study was to reveal factors which increase the risk factors for association of cancerous disease in patients with myositis. Furthermore, the authors explored the most common types of associated malignancies in their patients with myositis and characterize the clinical findings in a sub-group of anti-p155/140 positive patients.In this retrospective study, myositis patients with and without associated cancer were analysed (32 and 64 patients, respectively). In addition, anti-p155/140 positive and negative groups were compared, irrespective to the presence of associated malignancies.The risk for associated malignancy was higher in patients with severe muscle and skin symptoms and those with dermatomyositis. Furthermore, increased risk for malignancy was noted in the presence of particular skin symptoms and the absence of systemic symptoms. The anti-p155/140 antibody was proved to be a feasible marker of an independent clinical sub-group which overlapped clinical characteristics with cancer-associated myositis.These results may help the identification of patients with myositis with a higher risk for associated malignancy.Bevezetés: Az idiopathiás inflammatoricus myopathiák szisztémás autoimmun betegségek, jellegzetességük a proximalis végtagövi izmok progresszív gyengesége. A heterogén betegségcsoport legrosszabb prognózisú alcsoportja a tumorral társult myositis. Célkitűzés: Jelen tanulmány célja, hogy felderítse azokat a tényezőket, amelyek társuló daganatos megbetegedés kialakulásának kockázatát fokozzák myositises betegek esetében. További célja, hogy meghatározza a myositissel gyakran társuló daganatok típusait; az anti-p155/140 antitest jelenlétével összefüggő klinikai kép jellegzetességeit, különös tekintettel az antitest és a tumorral társult myositis kapcsolatára. Módszer: A szerzők a vizsgálatban részt vevő betegek klinikai dokumentációinak retrospektív elemzésével összehasonlították a kialakított primer, tumorral nem társult (n = 64) és tumorral társult (n = 32) myositises betegcsoportokat; valamint anti-p155/140 antitest pozitív és negatív alcsoportokat a legfontosabb klinikai, laboratóriumi és immunológiai tulajdonságok szempontjából. Eredmények: Daganat kialakulásának kockázatát növelő tényezők a súlyos izom- és bőrtünetek, dermatomyositis diagnózisa, egyes bőrtünetek jelenléte és a szisztémás tünetek hiánya. Az anti-p155/140 antitest önálló szerológiai alcsoportot jelöl ki, amely tulajdonságaiban átfedést mutat a tumorral társult myositissel. Következtetések: A vizsgálat eredményei segíthetik a daganat kialakulásának nagyobb kockázatával bíró myositises betegek azonosítását. Orv. Hetil., 2014, 155(36), 1437–1444.

Objective.To determine the prevalence, distribution, and clinical manifestations of arthritis in a cohort of patients with idiopathic inflammatory myopathies (IIM). Associations with autoantibody status and HLA genetic background were also explored.Methods.Consecutive patients with IIM treated in a single center were included in this cross-sectional study (n = 106). History of arthritis, 68-joint and 66-joint tender and swollen joint index, clinical features of IIM, and autoantibody profiles were obtained by clinical examination, personal interview, and review of patient records. High-resolution genotyping in HLA-DRB1 and HLA-DQB1 loci was performed in 71 and 73 patients, respectively.Results.A combination of patients’ medical history and cross-sectional physical examination revealed that arthritis at any time during the disease course had occurred in 56 patients (53%). It was present at the beginning of the disease in 39 patients (37%) including 23 cases (22%) with arthritis preceding the onset of muscle weakness. On physical examination, 29% of patients had at least 1 swollen joint. The most frequently affected areas were wrists, and metacarpophalangeal and proximal interphalangeal joints. Twenty-seven out of the 29 anti-Jo1-positive patients had arthritis at any time during the course of their illness; this prevalence was significantly higher compared to patients without the anti-Jo1 autoantibody (p < 0.0001). No association of arthritis with individual HLA alleles was found.Conclusion.Our data suggest that arthritis is a common feature of myositis. It is frequently present at the onset of disease and it may even precede muscular manifestations of IIM. The most common presentation is a symmetrical, nonerosive polyarthritis affecting particularly the wrists, shoulders, and small joints of the hands. We have confirmed a strong association of arthritis with the presence of the anti-Jo1 antibody.

OBJECTIVE: The HLA 8.1 ancestral haplotype (HLA-B*08/DRB1*03/DQA1*05/DQB1*02) is associated with adult/juvenile idiopathic inflammatory myopathy (IIM), but confers a greater strength of association in patients possessing anti-Jo-1 or anti-PM-Scl antibodies. The HLA-DPB1 gene is centromeric to other HLA class II loci and separated by a recombination hotspot. We investigated whether HLA-DPB1 associations differ between anti-Jo-1 and anti-PM-Scl antibody-positive IIM cases. METHODS: Two hundred and thirty-three adult IIM patients (73% females, 49.4 +/- 13.6 years) with PM (n = 89), DM (n = 88) and myositis associated with another CTD (n = 55) and 85 juvenile DM patients (75% females, 6.2 +/- 3.6 years) were compared with 678 UK Caucasian controls. Patients/controls were genotyped for HLA-DPB1 and DRB1 alleles. Myositis-specific and associated antibodies were identified in cases using immunoprecipitation. RESULTS: HLA-DPB1*0101 was associated with IIM overall [22 vs 13% controls, corrected probability (P(corr)) = 2 x 10(-03); odds ratio (OR) 2.0; 95% CI 1.4, 2.9], PM (P(corr) = 7 x 10(-03); OR 2.5; 95% CI 1.5, 4.4) and anti-Jo-1 (P(corr) = 3 x 10(-5); OR 4.1; 95% CI 2.1, 7.8). No significant DPB1*0101 difference was present between anti-PM-Scl cases and controls. The HLA-DPB1*0101 association in IIM overall cases was dependent on the presence of DRB1*03. A number of HLA-DRB1*03/DPB1 haplotypes were identified, but only DRB1*03/DPB1*0101 was associated with anti-Jo-1 antibody-positive cases. CONCLUSIONS: The HLA-DRB1*03/DPB1*0101 haplotype is a risk factor for anti-Jo-1 antibody-positive IIM. Thus, although DRB1*03 is strongly associated with possession of either anti-Jo-1 or anti-PM-Scl, differing antibody associations are observed at the HLA-DPB1 locus.

There is increasing evidence that patients with polymyositis and dermatomyositis have specific clinico-serological profiles. Myositis-specific autoantibodies target intracellular proteins involved in key processes such as translocation and nuclear transcription, and are closely linked to patterns of disease expression. This review highlights the recent work on novel myositis-specific autoantibodies, their autoantigen targets, the relationship to clinical subsets and potential role in pathogenesis.During the annual review period novel autoantibodies have been described in adult-onset dermatomyositis (anti-SAE autoantibodies) and juvenile dermatomyositis (anti-p155/140 autoantibodies) (anti-MJ or anti-p140 autoantibodies). These findings are important because the function of the autoantigen targets may point to shared pathogenic pathways. Studies highlighting the potential role of autoantigen-driven responses and autoantibody production in disease initiation and propagation are discussed, as well as further evidence on the relationship between autoantigens and corresponding target tissues.Considerable progress has been made emphasizing the striking association between genotype, serotype and clinical phenotype in the myositis disease spectrum. Further characterization of the identity and function of autoantigen systems in target tissues will greatly facilitate investigation of models of autoimmunity in this disease.

Objectives: Autoantibodies to a novel autoantigen small ubiquitin-like modifier activating enzyme (SAE) associated with dermatomyositis (DM) have previously been identified. The aim of this study was to establish the frequency of anti-SAE autoantibodies in a UK myositis cohort and investigate clinicoimmunogenetic associations. Methods: Clinical data and sera were studied from 266 patients recruited to the Adult Onset Myositis Immunogenetic Collaboration. Myositis sera, control sera including 250 patients with other connective tissue diseases and 50 healthy participants were screened using radio-immunoprecipitation. Immunodepletion was performed on all sera immunoprecipitating 40 and 90 kDa bands to confirm the presence of anti-SAE. DNA from 202 patients with myositis was genotyped for human leucocyte antigen (HLA)-DRB1 and DQB1; DQA1 data were inferred. Results: Out of 266 patients with myositis, 11 (4%) were positive for anti-SAE, which was found exclusively in DM with a frequency of 8%. Patients with anti-SAE had a high frequency of cutaneous lesions including heliotrope (82%) and Gottron rash (82%). Of the 11, 9 (82%) had systemic features and 7 of 9 (78%) developed dysphagia. Of those nine, seven (78%) presented with skin disease before myositis onset. All patients with anti-SAE possessed at least one copy of HLA-DQB1*03. HLA-DRB1*04-DQA1*03-DQB1*03 was a significant risk factor in anti-SAE positive versus patients who were anti-SAE negative (haplotype frequency 18% vs 6%, p Conclusions: Anti-SAE is a myositis-specific autoantibody that identifies a subset of patients with adult DM. The majority of patients with anti-SAE presented with cutaneous disease and progressed to myositis with systemic features including dysphagia. This novel autoantibody has a strong association with the HLA-DRB1*04-DQA1*03-DQB1*03 haplotype.

OBJECTIVES: Myositis-specific autoantibodies (MSAs) may define homogeneous clinical subsets of adult patients with dermatomyositis (DM). Recently, there have been descriptions of novel autoantibodies in DM. This study was conducted to establish the clinical significance of anti-p155/140 autoantibodies in juvenile DM (JDM). METHODS: The first 116 children recruited to the JDM National Registry and Repository (UK and Ireland) were studied. Comprehensive clinical features were recorded and sera screened for anti-p155/140 autoantibodies using radio-immunoprecipitation. Sera from adults with DM (n = 20), PM (n = 25), SSc (n = 150), SLE (n = 40) and healthy subjects (n = 50) were used for comparison. Immunodepletion experiments were used to establish whether the p155/140 kDa targets recognized by JDM sera were the same as adult DM sera. RESULTS: Twenty-seven out of 116 (23%) JDM cases were positive for anti-p155/140 in comparison with 6/20 (30%) adults with DM. Immunodepletion confirmed that the 155/140 kDa proteins recognized by JDM and adult DM sera were the same targets. All other adult control sera were negative for anti-p155/140 autoantibodies. There was a higher frequency of males in the anti-p155/140-positive JDM group (P = 0.02). JDM patients with anti-p155/140 autoantibodies had significantly more cutaneous involvement including Gottron's papules (P = 0.003), ulceration (P = 0.005) and oedema (P = 0.013). The distribution of skin lesions was more extensive particularly periorbitally (P = 0.014) and over the small (P < 0.001) and large joints (P = 0.003). CONCLUSIONS: Anti-p155/140 autoantibodies are clinically significant in JDM and may define a clinical subset in terms of disease severity and outcome. The same autoantigen target is detected in adult DM patients

Objective. To examine single-nucleotide polymorphisms (SNPs) of the protein tyrosine phosphatase N22 gene (PTPN22) and to study the relationship between PTPN22 and the HLA region in patients with idiopathic inflammatory myopathies (IIMs). Methods. PTPN22 SNPs were assessed in a large, cross-sectional, case-control study from the UK involving patients with adult or juvenile IIM, comprising patients with polymyositis (PM) (n = 114), dermatomyositis (DM) (n = 102), myositis associated with another connective tissue disease (myositis-CTD overlap syndrome) (n = 64), or juvenile DM (n = 101), in comparison with 748 control subjects. Seventeen PTPN22 SNPs were genotyped using the Sequenom MassArray iPLEX platform. Serotyping for myositis-specific/myositis-associated autoantibodies (MSAs/MAAs) was performed by radioimmunoprecipitation. Results. A significant association was noted between the R620W variant (rs2476601) and IIM (corrected P [Pcorr] = 0.0009 versus controls), and specifically with the clinical subgroup of PM (Pcorr = 0.003 versus controls). A weaker association was noted with juvenile DM (Pcorr = 0.009 versus controls). No significant associations were noted after stratification by serologic subgroups. The association with the R620W variant was independent of alleles forming the HLA 8.1 haplotype. No other PTPN22 SNPs were associated with IIM. The PTPN22 haplotype containing the R620W T allele was the only haplotype significantly associated with IIM. Conclusion. The R620W variant is a significant risk factor for IIM, independent of the HLA 8.1 haplotype. Unlike that in the HLA region, risk is not increased in individuals possessing MSAs/MAAs. These results are further evidence that the PTPN22 gene confers autoimmune susceptibility. © 2008, American College of Rheumatology.

Objective Myositis-specific autoantibodies (MSAs) are directed against cell machinery proteins such as aminoacyl–transfer RNA synthetases, signal recognition particle, Mi-2, and CADM-140. Because serologic subsets can define patients with specific clinical manifestations, the identification of further MSAs may help to identify additional disease subsets within the myositis spectrum. Methods Sera from 20 adult patients with dermatomyositis (DM) were screened for autoantibodies. Two patients were further characterized due to the presence of the same novel immunoprecipitation (IP) pattern on sodium docecyl sulfate–polyacrylamide gel electrophoresis (SDS-PAGE) and similar clinical manifestations. Both patients presented with cutaneous disease, followed by proximal myositis 6 months later. Both patients had associated nonspecific interstitial pneumonia but no signs of malignancy. The novel targets were identified using a combination of IP, SDS-PAGE, and matrix-assisted laser desorption ionization–time-of-flight mass spectrometry. Results Indirect HEp-2 immunofluorescence on sera from both patients displayed a diffuse, coarse, speckled, nucleolar-sparing pattern. IP revealed the presence of previously uncharacterized bands at ∼40 kd and ∼90 kd in both patients. The novel targets were identified as the small ubiquitin-like modifier 1 (SUMO-1) activating enzyme A subunit and SUMO-1 activating enzyme B subunit. Conclusion These findings reveal previously uncharacterized autoantibodies directed against a protein involved in posttranslational modification, the SUMO activating enzyme, in 2 patients with DM who had similar clinical features, including severe skin disease and interstitial pneumonia.

Background B-cell activating factor of the TNF family (BAFF)is important for B cell maturationand plays a role in (auto)antibodies production. Elevated serum levels in relation to autoantibodies were documented in patients with IIMs. Promoter region of BAFF gene contains several known sites with single nucleotide polymorphism (SNPs). An association between rs9514828 (-871 C/T) SNP and susceptibility to idiopathic thrombocytopenic purpura was shown and possible relations to systemic lupus erythematosus, rheumatoid arthritis or Sjogren’s syndrome were suggested. Objectives To describe four BAFF SNPs located in the BAFF gene promoter in patients with IIMs and analyze relation of particular SNPs to serum BAFF (s-BAFF) levels in autoantibody positive patients. Methods Patients with polymyositis (n=146), dermatomyositis (DM, n=150), juvenile DM (n=11), inclusion body myositis (n=4) and 103 healthy individuals were included. Four SNPs located upstream in the BAFF gene (rs9514827 (-2841 T/C); rs3759467 (-2704 T/C); rs1041569 (-2701 T/A); rs9514828 (-871 C/T)) were analyzed by direct DNA sequencing. Levels of s-BAFF were measured using ELISA. Autoantibodies were detected with immunoprecipitation and Line blot assay. The chi square test for analysis of alleles and genotypes associations and SNPStats software for haplotype frequency studies wereused. Results Significantly higher frequency of -2701T allele was present in patients (18%) compared to healthy controls (12%) (p=0.029; OR 1.68 (CI 95%=1.05-2.7)). Additionally, increased -2841T allele (p=0.09), -2841TT, CT genotype (p=0.07) and -2701TT, AT genotype (p=0.08) frequencies were observed in patients. SNPs were in strong linkage disequilibrium and formed four common haplotypes (TTAC, CTAT, TCAC, TTTT), with significantly different frequency (> 9%) distributions between patients and controls (global P=0.038). Higher frequency of TTTT haplotype was present in patients (16%) compared to controls (9%; OR 1.99 (95% CI 1.15-3.47; P=0.015)) relative to the most frequent haplotype TTAC. Significantly higher s-BAFF levels were detected in patients compared to healthy controls (P Conclusions -2701T allele and TTTT haplotype in the four SNPs located upstream of the BAFF gene were associated with the presence of myositis. Patients with anti-Jo-1 antibodies have higher BAFF levels if they are carriers of -2704T allele. These findings point to differential genetic regulation of BAFF production in patients with IIMs, but need to be validated in the second independent cohort of patients. Acknowledgements Grant support of IGA -Ministry of Health of the Czech Republic NT/12438-4. Disclosure of Interest None Declared

Background Increased serum levels of B cell activating factor (BAFF) have been detected in patients with idiopathic inflammatory myopathies (IIM) [1], which in anti-Jo-1 positive patients correlate with serum autoantibody concentration. The correlation of BAFF expression with disease activity in IIM patients has recently been described. Objectives To investigate serum BAFF levels in anti-PM-Scl positive patients with co-existent myositis and to assess the association with clinical disease activity in a multi-center myositis cohort. Methods Serum BAFF levels of 37 anti-PM-Scl positive IIM patients from two European countries and in 57 healthy controls were measured using ELISA. Nineteen longitudinal serum samples with corresponding clinical data were also obtained. Clinical data were derived from the Euromyositis database (www.euromyositis.eu). Results Serum levels of BAFF in anti-PM-Scl positive PM/DM patients were significantly higher compared to healthy controls (P=0.008) , but there was no statistically significant difference between PM or DM patients (P>0.05) . BAFF levels correlated with both muscular (r=0.509, P=0.002) and extramuscular disease activity (r=0.487, P=0.003). There was a negative correlation with manual muscle test (MMT8) results - increased muscle weakness thus correlated with increased serum BAFF levels (r=-0.423, P=0.025) . The composite disease activity (DA) scores MITAX and MYOACT correlated positively with BAFF levels; MITAX: r=0.374, P=0.027 ; MYOACT: r=0.430, P=0.010. There was a correlation with disease activity (DA) of various systems: Constitutional DA (r=0.382, P=0.023) , Cutaneous DA (r=0.471, P=0.004) , Gastrointestinal DA (r=0.545, P=0.001) and Pulmonary DA (r=0.524, P=0.001) . Furthermore, longitudinal change (∆) in BAFF levels correlated with ∆Physician Global DA (r = 0.6834, P = 0.0035) , ∆Muscular DA (r=0.786, P , and ∆MITAX Score (r=0.672, P=0.002) . Change in BAFF correlated significantly also with ∆MYOACT (r=0.698, P=0.001) and with its components: ∆Cutaneous DA (r=0.491, P=0.033) , ∆Skeletal DA (r=0.588, P=0.008) , ∆Gastrointestinal DA (r=0.548, P=0.015) , ∆Pulmonary DA (r=0.491, P=0.039) and ∆Cardiovascular DA (r=0.471, P=0.042) . Conclusions Serum levels of BAFF are increased in anti-PM-Scl positive patients with IIM, where BAFF levels correlate with clinical disease activity assessments. Furthermore, longitudinal changes in BAFF levels over time also correlate with changes in disease activity measures. These findings indicate that BAFF is likely implicated in the pathogenesis of PM/DM. BAFF is thus a potential biomarker in IIM. References O Krystůfkova, T Vallerskog, S Barbasso Helmers, H Mann, I Půtova, J Bělacek, V Malmstrom, C Trollmo, J Vencovský, I E Lundberg, Increased serum levels of B cell activating factor (BAFF) in subsets of patients with idiopathic inflammatory myopathies, Ann Rheum Dis 2009;68:836-843 doi:10.1136/ard.2008.091405 Acknowledgements IGA -Ministry of Health of the Czech Republic NT/12438-4. Disclosure of Interest None Declared

Background Hydroxy-methyl-glutaryl Coenzyme-A reductase (HMGCR) inhibitors or statins are a well-acknowledged cause of a spectrum of myopathic consequences including an asymptomatic increase of creatine kinase (CK), myalgias, myositis and rhabdomyolysis. A unique autoantibody with specificity against 200-kd and 100-kd proteins has been recently associated with statin induced myositis (1) based on identification of cases with features of necrotizing myopathy. The 100kd autoantigen has been identified as HMGCR (2). We sought to further characterize cases of clinically suspected statin-induced myositis using clinical, serological and pathological data. Objectives The aim was to characterize statin induced myositis patients in a clinical setting and test the utility of the newly identified anti-200/100 autoantibody. Methods Patients with a statin induced myositis were identified from a large tertiary myositis referral centre in Salford, UK. Case records of all patients were reviewed with selected patients’ blood samples tested for anti-200/100 autoantibody. Clinical features, concomitant medications, co-morbidities, immunology, electromyography (EMG), magnetic resonance imaging (MRI) and muscle biopsies for each patient were reviewed. Results 10 patients were identified with a clinical diagnosis of statin induced myositis. Mean age of diagnosis was 59 years (70% male). Median CK level detected at onset was 1,750 IU/litre (range 28-11,984). 9/10 patients were on a lipophilic statin (simvastatin/atorvastatin) with 1 patient on a hydrophilic statin (rosuvastatin); mean daily dose of 39mg/day prior to symptom onset. 5/10 patients were on a concomitant medication known to interact with a statin (amiodarone, proton pump inhibitors, high dose vitamin D). 3/10 patients were anti-nuclear-antibody positive (2 had low titres, 1/100; 1 positive 1/1000), whilst 2 patients were anti-Ro antibody positive. 6 patients demonstrated some evidence of myositis on MRI, of which 3 patients exhibited myopathic changes on EMG. 8 patients had evidence of myopathic muscle on biopsy, 2 patients with type II fibre atrophy. Of the 7 patients tested for anti-HMGCR by Western blotting using a recombinant source, 6 tested positive. 2 patients who tested strongly 200/100 positive required immunosuppression and had biopsy features of necrosis, phagocytosis and regeneration. 2 further 200/100 positive patients (1 strong and 1 weak positive) had occasional necrotic fibres with little regenerative activity on biopsy and did not require further treatment. The remaining 2 200/100 positive patients had no features of necrosis on biopsy, one of whom required immunosuppression without corticosteroids. Conclusions EMG and MRI were non-specific in identifying patients with a statin induced myositis, whilst CK levels varied significantly in this group. A strongly positive anti-200/100 antibody in combination with a necrotizing myopathy on muscle biopsy could be useful clinically to identify which patients have an autoimmune element to their disease, hence may potentially benefit from immunosuppression. References Christopher-Stine L et al. Arthritis Rheum 2010;62(9):2757–66. Mammen AL et al. Arthritis Rheum. 2011 Mar;63(3):713-21. Acknowledgements MJ is a MRC Clinical Training Fellow funded by the North West England Medical Research Council Fellowship Scheme in Clinical Pharmacology and Therapeutics. Disclosure of Interest None Declared

Background Idiopathic inflammatory myopathies (IIM) are frequently accompanied by presence of autoantibodies. A correlation of anti-Jo-1 and anti-SRP antibody levels with disease activity and creatine kinase levels has been described. Recently a new anti-PM1α quantitative ELISA test detecting antibodies to the main epitope of PM-Scl-100 has become available. Objectives To investigate the prevalence of anti-PM1α autoantibodies and association with clinical symptoms, clinical disease activity and serum CK in a multicenter myositis cohort. Methods Two hundred and thirty eight consecutive patients with established IIM (103 DM, 99 PM, 8 JDM, 3 IBM and 25 IIM/CTD-overlap syndrome) were tested for the presence of anti PM-Scl autoantibodies by immunoblot and by immunoprecipitation. Eight additional anti-PM-Scl positive sera were also obtained. Serum levels of anti-PM1α autoantibodies were detected by ELISA kit (Dr. FOOKE Laboratorien GmbH, Neuss, DE). Clinical data were derived from the Euromyositis database (www.euromyositis.eu). Global and organ clinical disease activities were assessed by Myositis Activity Assessment Tool (MYOACT) 10 cm visual analogue scales. Results 19/238 (8%) patients (11 DM, 2 PM and 6 IIM/CTD-overlap syndrome (3 DM + SSc, 2 PM + SSc, 1 PM + SjS)) were positive for anti-PM-Scl in immunoblot, immunoprecipitation and anti-PM1α ELISA. 19 PM-Scl+ were 16/181 women and 3/57 men, average age 50.5 years (22.0 – 74.2) and average disease duration 3.0 years (0 – 11.6 years). Good agreement between detection tests was found. The most common clinical features among anti-PM-Scl positive patients were muscle weakness (96%), interstitial lung disease (77%), Raynaud’s phenomenon (69%) and mechanic’s hands (65%). One patient had a cancer. Anti-PM1α levels correlated with serum CK activity in the DM group (p=0.041, r=0.533) and with constitutional disease activity and seriousness of dysphagia in the PM group (p=0.048, r=0.768 and p=0.007, r=0.927). Furthermore longitudinal change in anti-PM1α levels correlated with HAQ scores in the whole group (p=0.016, r=0.730) and with global disease activity score in DM group (p=0.023, r=0.685), but not with other MYOACT parameters. Conclusions Anti-PM-Scl autoantibodies are detected in 8% of patients with myositis. They are more frequent in those with DM and overlap syndromes. Presence of these autoantibodies is associated with muscle weakness, ILD, Raynaud’s phenomenon and mechanic’s hands. Anti-PM1α levels correlate with serum CK levels in DM and their change is correlated with change of HAQ scores in the whole group and with MYOACT scores in DM group. This suggests that the quantitative measurement of anti-PM-1α may be a useful tool in the assessment of patients with this syndrome. Disclosure of Interest None Declared

Background and Objectives B-cell activating factor of the TNF family (BAFF) is important for B cell maturation and plays a role in (auto)antibodies production. Elevated serum levels in relation to autoantibodies were documented in patients with IIM. Promoter region of BAFF gene contains several known sites with single nucleotide polymorphism (SNPs). An association between Rs9514828 (–871 C/T) SNP and susceptibility to idiopathic trombocytopaenic purpura was shown and possible relations to systemic lupus erythematosus, rheumatoid arthritis or Sjogren’s syndrome were suggested but in IIM have not been studied yet. Here, we analysed relation of four BAFF SNPs located in the BAFF gene promoter with the development of IIM. Materials and Methods 146 patients with polymyositis (PM), 150 with dermatomyositis (DM), 11 patients with juvenile DM and 4 patients with inclusion body myositis and 103 healthy individuals were included. Four SNPs located upstream in the BAFF gene (Rs9514827 (–2841 T/C); Rs3759467 (–2704 T/C); Rs1041569 (–2701 T/A); Rs9514828 (–871 C/T)) were analysed by direct DNA sequencing. Serum levels of BAFF (s-BAFF) were evaluated using ELISA. Autoantibodies were detected with immunoprecipitation. The chi square test for analysis of alleles and genotypes associations and SNPStats software for haplotype frequency studies were used. Results Significantly higher frequency of –2701T allele was present in patients (18%) compared to healthy controls (12%) (P = 0.029; OR 1.684 (CI 95% = 1.050 – 2.699)). Additionally, increased –2841T allele (P = 0.086), –2841TT, CT genotype (P = 0.066) and –2701TT, AT genotype (P = 0.079) frequencies were observed in patients. SNPs were in strong linkage disequilibrium and formed four common haplotypes (TTAC, CTAT, TCAC, TTTT), with significantly different frequency (>9%) distributions between patients and controls (global P-value Conclusions We describe significant association of SNP (Rs1041569) with myositis and a relation of SNP (Rs3759467) to presence of anti-Jo-1 autoantibodies and s-BAFF levels. These results should be confirmed in an independent cohort of patients and possible relations of s-BAFF levels with disease activity and treatment should be considered. Acknowledgement IGA -Ministry of Health of the Czech Republic NT/12438–4.

Background and Objectives The idiopathic inflammatory myopathies (IIM) are systemic connective tissue diseases in which autoimmune pathology is responsible for promotion of chronic muscle inflammation and weakness. As in many other autoimmune diseases, the development of IIM is also associated with genes of HLA complex. The aim of this study was to determine the basic relation between alleles of HLA genes and IIM. Materials and Methods We have performed low to high resolution genotyping to characterise the allelic profiles of HLA-DRB1, -DQB1 and -DQA1 loci in a large group of single centre cohort of patients suffering from IIM (n = 269). The genomic DNA was prepared by standard DNA extraction methods and the HLA typing was done using the commercial LABType® SSO kit (One Lambda, USA). Statistical evaluation of results was done with chi-2 test and Fisher exact test. Autoantibody profiles were analysed with radioactive immunoprecipitation. Results The frequencies of HLA-DRB1*03:01 and -DRB1*16:01 alleles were increased in IIM patients and the difference reached statistical significance when compared to healthy controls (P Presence of HLA-DRB1*03:01 allele was associated with anti-Jo-1, anti-Ro52, or anti-Pm-Scl positivity in all IIM patients (P The DRB1*16:01 allele was associated with negativity of all studied autoantibodies, particularly in subgroup of DM patients (P Conclusions This study identifies different genetic background between patients with dermatomyositis and polymyositis in a homogenous population of patients from a single centre. Acknowledgement This work is supported by Internal Grant Agency of Ministry of Health of the Czech Republic NT/12438–4 and NT/13699.

Autoantibodies targeting intracellular proteins involved in key processes are detected in patients with idiopathic inflammatory myopathies. These myositis-specific autoantibodies have been increasingly demonstrated to correlate with distinct clinical phenotypes within the myositis spectrum. This review highlights the clinical associations of the myositis-specific autoantibodies, with particular attention to the recently identified and characterized novel myositis autoantibodies: p155/140, p140 (MJ), CADM-140 (MDA5), SAE, and 200/100.

Myositis specific autoantibodies (MSA), exclusively found in patients with Idiopathic Inflammatory Myopathies can be detected in approximately 60% of children with JDM. Anti-MDA5 antibodies, a subgroup of MSA, appear to be associated with clinically amyopathic myositis, rapidly progressive interstitial lung disease (RP-ILD) and a poor prognosis in adult East Asian dermatomyositis patients. Small studies in Japanese children with JDM have suggested similar disease phenotype. This contrasts dramatically with findings in predominantly Caucasian US adult populations where anti-MDA5 has been associated with a distinct cutaneous phenotype and no association with RP-ILD has been found.