Novel classification of idiopathic inflammatory myopathies based on overlap syndrome features and autoantibodies: analysis of 100 French Canadian patients

Clinical characteristics of idiopathic inflammatory myopathies related to anti-SRP: a single center experience

Idiopathic inflammatory myopathy (IIM) with autoantibodies recognizing the signal recognition particle (SRP) is characterized by prominent proximal weakness, infrequent extramuscular involvement, dramatically elevated creatine kinase levels, and myofiber necrosis with few inflammatory cell infiltrates in muscle tissue. To enhance understanding of the clinically used diagnosis and treatment of this disease, this study presents a single-center experience and analysis of a Chinese cohort with anti-SRP IIM. The most recent European Neuromuscular Center criteria were used to include Anti-SRP IIM patients from September 2016 to November 2019. Prior to treatment initiation, all sera were collected for the detection of anti-SRP autoantibodies and other myositis-related autoantibodies. Muscle strength, concurrent autoimmune conditions, comorbidities like interstitial lung disease (ILD), treatment outcomes, and follow-up results were also documented. Univariate logistic regression was employed to determine factors affecting prognosis. Among 271 patients with IIM, we identified 23 (8.5%) patients with anti-SRP IIM. Lower limb muscle weakness was frequently more severe. Interstitial lung disease (ILD) was observed in 50% of anti-SRP IIM patients. The presence of ILD may serve as a predictor of a poor prognosis, as revealed by univariate logistic regression analysis (odds ratio, 3.8, 95% CI: 1.0-6.8, p = 0.05).This Chinese Anti-SRP IIM cohort from Hunan province seems to have higher incidences of ILD, and associated ILD may be a risk factor for a poor prognosis. To fully understand the specific role of the anti-SRP autoantibody in this unique subset with ILD, further research is necessary.

273rd ENMC International workshop: Clinico-Sero-morphological classification of the Antisynthetase syndrome. Amsterdam, The Netherlands, 27-29 October 2023

Among the idiopathic inflammatory myopathies, patients harbouring an Antisynthetase syndrome exhibit a unique clinical picture, with characteristic signs such as myositis, interstitial lung disease, arthritis, rash, and/or fever. Characteristic morphological features on skeletal muscle biopsies differentiate Antisynthetase syndrome from other forms of myositis. Autoantibodies typically recognizing one of the members of the aminoacyl-tRNA synthetase family of proteins can be detected in the serum of such patients, with anti-Jo1 being most frequent. Until now, an international consensus definition of the Antisynthetase syndrome is lacking, hence this workshop has undertaken the task to inform about the clinical, morphological and autoantibody profiles of Antisynthetase syndrome. The authors also expand their aims by giving management and therapeutic strategies, and finally provide precise classification criteria for Antisynthetase syndrome.

Distinct Transcript-Level Expression Profiles and Unique Alternative Splicing in Inflammatory Myopathies

OBJECTIVE

The pathogenesis of inflammatory myopathies is poorly understood and there is a need to dissect the transcriptome in more granular ways beyond gene expression.

METHODS

We used a set of muscle RNA-sequencing data from different myositis subtypes grouped by their specific autoantibodies (n = 152). We quantified annotated RNA transcripts for each myositis subtype and identified uniquely expressed RNA as well as transcriptional similarities among myositis types. In addition, we quantified event-based alternative splicing with predicted protein changes. And finally, we searched for cryptic exons.

RESULTS

We saw considerable overlap in RNA expression among subtypes. In addition, MADCAM1 was previously shown to be uniquely expressed in Mi-2 myositis; we discovered it was two noncanonical transcripts that predominantly contributed to the observed increased expression. At the transcriptional level, dermatomyositis subtypes were least similar to inclusion body myositis (IBM) or Jo1, followed by HMGCR, then SRP and other dermatomyositis subtype. Additionally, we discovered many alternative splicing events that were unique by myositis subgroup, including events in muscle dystrophy genes and one event in SRP72, which was seen uniquely in SRP myositis. Finally, we looked for previously reported cryptic exons in IBM and did not find them.

CONCLUSION

The large degree of transcriptional overlap among myositis subtypes reinforces the need to use disease (in addition to healthy) controls to find unique features of autoimmune disease. Unique alterations in the transcriptome that are seen in one myositis subtype and not others advance our understanding of distinct disease pathology.

Prompt response to rituximab in a patient with resistant polymyositis with complications of dysphagia and dysphonia: a case report

Introduction and importance

Polymyositis is an inflammatory process, primarily affecting proximal muscles, characterized by elevated muscle enzymes and distinctive electromyography patterns.

Case presentation

The authors present a case of a 33-year-old male patient experiencing complications of polymyositis, including pharyngeal and laryngeal involvement leading to dysphagia and dysphonia. Steroids and intravenous immunoglobulin (IVIG) therapy proved ineffective. Subsequently, rituximab was administered, resulting in significant improvement in dysphagia, dysphonia, and proximal muscles within 3 days of the initial rituximab dose. Additionally, there was a remarkable decrease in creatine phosphokinase (CPK) levels.

Clinical discussion

Immune-mediated myopathies (IMM) are rare diseases characterized by muscle inflammation and weakness. This case of probable polymyositis, diagnosed through clinical features and elevated CPK, was complicated by the patient's lack of response to glucocorticoids and IVIG therapy. Remarkably, rituximab treatment led to rapid improvement in muscle strength and symptoms, highlighting its potential effectiveness in refractory cases of polymyositis.

Conclusions

Primary treatment for cases of polymyositis typically involves the use of glucocorticoids. However, approximately half of the patients do not respond adequately to corticosteroids alone. Alternatives, in such cases, encompass IVIG therapy and rituximab.

Issues in autoantibody tests used in the classification criteria for autoimmune rheumatic diseases: the laboratory autoimmunologist's perspective

Classification criteria of autoimmune rheumatic diseases are an important means to define homogenous groups of patients that can be compared across studies for clinical trials and research purposes. The measurement of autoantibodies is a relevant aspect in the definition of classification criteria, with a significant weight in the scores necessary to classify patients with autoimmune rheumatic diseases. The impact of autoantibodies has gradually increased over the years, contributing to the evolution and improvement of the classification criteria. However, these criteria often do not take into consideration how autoantibodies are measured, i.e. differences in diagnostic accuracy of the methods. This is a critical point especially when obsolete analytical methods that are no longer used in many clinical laboratories are taken into consideration. In this review we have critically examined assays and methods for the determination of autoantibodies that are (or could be) included among the classification criteria of autoimmune rheumatic diseases in light of more recent evidence and technology evolution.

Clinical relevance of positively determined myositis antibodies in rheumatology: a retrospective monocentric analysis

BACKGROUND

The increased availability of myositis autoantibodies represents new possibilities and challenges in clinical practice (Lundberg IE, Tjärnlund A, Bottai M, Werth VP, Pilkington C, de Visser M, et al. 2017 European League Against Rheumatism/American College of Rheumatology classification criteria for adult and juvenile idiopathic inflammatory myopathies and their major subgroups. Ann Rheum Dis. 2017;76:1955-64. https://doi.org/10.1136/annrheumdis-2017-211468 .). The aim of this study was to perform a retrospective data analysis of patient cases with positive myositis autoantibodies to analyse their significance in routine rheumatology practice.

METHODS

A monocentric analysis of all the orders used to determine myositis autoantibodies from July 2019 to May 2022 in the Department of Rheumatology, Krankenhaus Porz am Rhein, Cologne, Germany, was carried out.

RESULTS

In the defined time interval, a total of 71,597 laboratory values for the antibodies mentioned above were obtained. A total of 238 different positive autoantibodies ​​were detected in 209 patients. Idiopathic inflammatory myopathy was diagnosed in 37 patients (18%), and inflammatory rheumatic diseases other than idiopathic inflammatory myopathy were diagnosed in 90 patients (43%). No inflammatory rheumatic disease was diagnosed in 82 patients (39%). General clusters of clinical manifestations were observed.

CONCLUSIONS

In our cohort, we were able to show that a relevant proportion of patients with positive myositis antibodies did not have idiopathic inflammatory myopathies or inflammatory rheumatic diseases. This finding indicates the importance of myositis autoantibodies in this group of patients. However, further studies on the course of symptoms and examination results in patients without inflammatory rheumatic diseases and with positive myositis antibodies are necessary.

Combination of Sjögren's syndrome and anti-Ku syndrome complicated by the development of mucosa-associated lymphoid tissue lymphoma: case review and systematic review of the literature

The frequency of antibodies to Ku varies in various autoimmune diseases. In 2019, Spielmann et al. identified two types of anti-Ku syndrome based on a hierarchical clustering analysis. Sjögren's syndrome occurs both in the first type of anti-Ku syndrome and in the second type. Despite the fact that increased tissue expression of Ku proteins was noted in lymphocytic cells with focal sialoadenitis of the minor salivary glands in patients with primary Sjogren's syndrome, only 49 cases of a combination of anti-Ku antibodies and manifestations of Sjogren's syndrome have been described in the literature. Some researchers examined patients for the presence of Sjogren's syndrome only if they had anti-Ro or anti-La antibodies, although in the literature, there are descriptions of Sjogren's syndrome in the presence of only isolated anti-Ku antibodies, as in our case. Literature data on glandular and extraglandular manifestations of Sjögren's syndrome in anti-Ku-positive patients are limited. Below, we present the first case of Sjögren's syndrome in combination with the first type of anti-Ku syndrome complicated by the development of mucosa-associated lymphoid tissue (MALT) lymphoma. The article also provides a systematic review of the literature on the association of Sjögren's syndrome with anti-Ku antibodies.

Treatment strategies in MDA5-positive clinically amyopathic dermatomyositis: a single-center retrospective analysis

Melanoma differentiation-associated protein 5 (MDA5) antibody positive amyopathic dermatomyositis (DM) is a rare inflammatory disease. So far, there is no official treatment guideline in MDA5 amyopathic dermatomyositis, but early and aggressive immunosuppressive combination treatment can induce a stable remission. We retrospectively analyzed a cohort of eight patients (male n = 5) that were diagnosed with MDA5-positive amyopathic DM. Patient data comprised demographics, CT-guided diagnosis of pulmonary involvement, pulmonary function testing including forced vital capacity (FVC) and diffusing capacity for carbon monoxide (DLCO) data on baseline and mean long-term follow-up of 51 months (24-92 months) to evaluate treatment strategies. Depending on severity of organ involvement treatments were individualized including cyclophosphamide, immunoglobulins and plasmapheresis. Simultaneously, oral treatment with tacrolimus was commenced in four of the eight patients. Most patients received remission maintenance therapy with a combination of tacrolimus, rituximab and low dose steroids. In all patients, improvement in FVC was recorded and five patients achieved an improvement in DLCO. An improvement in the CT imaging morphological findings was observed in four patients. Awareness for the entirety of all clinical and disease-related findings of amyopathic DM is crucial, and remission maintenance is often achieved with a combination of tacrolimus and rituximab.

A variety of death modes of neutrophils and their role in the etiology of autoimmune diseases

Neutrophils are important in the context of innate immunity and actively contribute to the progression of diverse autoimmune disorders. Distinct death mechanisms of neutrophils may exhibit specific and pivotal roles in autoimmune diseases and disease pathogenesis through the orchestration of immune homeostasis, the facilitation of autoantibody production, the induction of tissue and organ damage, and the incitement of pathological alterations. In recent years, more studies have provided in-depth examination of various neutrophil death modes, revealing nuances that challenge conventional understanding and underscoring their potential clinical utility in diagnosis and treatment. This review explores the multifaceted processes and characteristics of neutrophil death, with a focus on tailored investigations within various autoimmune diseases. It also highlights the potential interplay between neutrophil death and the landscape of autoimmune disorders. The review encapsulates the pertinent pathways implicated in various neutrophil death mechanisms across diverse autoimmune diseases while also charts possible avenues for future research.

Anti-SAE autoantibody in dermatomyositis: original comparative study and review of the literature

OBJECTIVE

Among specific autoantibodies in DM, the anti-small ubiquitin-like modifier activating enzyme (SAE) antibody is rare. We aim to describe the clinical characteristics, cancer prevalence, and muscle pathology of anti-SAE-positive DM.

METHODS

Patients with a diagnosis of DM and sera positive for the anti-SAE antibody were recruited from 19 centres in this retrospective observational study. The available muscular biopsies were reviewed. We conducted a comparison with anti-SAE-negative DM and a review of the literature.

RESULTS

Of the patients in the study (n = 49), 84% were women. Skin involvement was typical in 96% of patients, with 10% having calcinosis, 18% ulceration and 12% necrosis; 35% presented with a widespread skin rash. Muscular disease affected 84% of patients, with mild weakness [Medical Research Council (MRC) scale 4 (3, 5)], although 39% of patients had dysphagia. Muscular biopsies showed typical DM lesions. Interstitial lung disease was found in 21% of patients, mainly with organizing pneumonia pattern, and 26% of patients showed dyspnoea. Cancer-associated myositis was diagnosed in 16% of patients and was responsible for the majority of deaths, its prevalence being five times that of the general population. IVIG therapy was administered to 51% of the patients during the course of the disease. Comparison with anti-SAE-negative DM (n = 85) showed less and milder muscle weakness (P = 0.02 and P = 0.006, respectively), lower creatinine kinase levels (P < 0.0001) and less dyspnoea (P = 0.003).

CONCLUSION

Anti-SAE positive DM is a rare subgroup associated with typical skin features but a potentially diffuse rash, a mild myopathy. Interstitial lung disease defines an organizing pneumonia pattern. Cancer associated DM prevalence is five times that of the general population.

TRIAL REGISTRATION

ClinicalTrials.gov, http://clinicaltrials.gov, NCT04637672.

From data to diagnosis: how machine learning is revolutionizing biomarker discovery in idiopathic inflammatory myopathies

Idiopathic inflammatory myopathies (IIMs) are a heterogeneous group of muscle disorders including adult and juvenile dermatomyositis, polymyositis, immune-mediated necrotising myopathy and sporadic inclusion body myositis, all of which present with variable symptoms and disease progression. The identification of effective biomarkers for IIMs has been challenging due to the heterogeneity between IIMs and within IIM subgroups, but recent advances in machine learning (ML) techniques have shown promises in identifying novel biomarkers. This paper reviews recent studies on potential biomarkers for IIM and evaluates their clinical utility. We also explore how data analytic tools and ML algorithms have been used to identify biomarkers, highlighting their potential to advance our understanding and diagnosis of IIM and improve patient outcomes. Overall, ML techniques have great potential to revolutionize biomarker discovery in IIMs and lead to more effective diagnosis and treatment.

Single-cell profiling of muscle-infiltrating T cells in idiopathic inflammatory myopathies

Idiopathic inflammatory myopathies (IIM) are rare autoimmune systemic diseases characterized by muscle weakness and the presence of muscle-infiltrating T cells. IIM represent a clinical challenge due to heterogeneity of symptoms and variability of response to immunosuppressive treatment. Here, we performed in-depth single-cell sequencing on muscle-infiltrating T cells and peripheral blood memory T cells in six patients with recently diagnosed IIM. We identified tissue resident memory T-cell (TRM ) signatures including the expression of HOBIT, XCL1 and CXCR6 in the muscle biopsies of all patients with IIM. Clonally expanded T-cell clones were mainly found among cytotoxic and TRM implying their role in the disease pathogenesis. Finally, identical expanded T-cell clones persisting at follow-up in the muscle tissue of two patients suggest their involvement in disease chronicity. Our study reveals a muscle tissue resident memory T-cell signature in patients with IIM and a transcriptomic map to identify novel therapeutic targets in IIM.

Anti-SMN autoantibodies in mixed connective tissue disease are associated with a severe systemic sclerosis phenotype

OBJECTIVES

The survival of motor neuron (SMN) complex has an essential role in the assembly of small nuclear ribonucleoproteins (RNP). Recent reports have described autoantibodies (aAbs) to the SMN complex as novel biomarkers in anti-U1RNP+ myositis patients. The aim of this study was to compare phenotypic features of anti-U1RNP+ mixed connective tissue disease (MCTD) patients with and without anti-SMN aAbs.

METHODS

A retrospective MCTD cohort was studied. Addressable laser bead immunoassay was used to detect specific anti-SMN aAbs with <300 mean fluorescence intensity (MFI) as normal reference range, 300-999 MFI as low-titre and ≥1000 MFI as high-titre positivity. Comparison of clinical features between anti-SMN+ and anti-SMN- subgroups used two-tailed Fisher's exact test, and logistic regression analyses.

RESULTS

Sixty-six patients were included. Median age at MCTD diagnosis was 40.6 years, and duration of follow-up was 12 years. Based on the highest available titre, 39 (59%) were anti-SMN+: 10 (26%) had low titre and 29 (74%) had high titre. Anti-SMN+ patients had a higher frequency of fingertip pitting scars (anti-SMN+ 23% vs anti-SMN- 4%, p=0.04), lower gastrointestinal (GI) involvement (26% vs 4%, p=0.04), and myocarditis (16% vs 0%, p=0.04). The combined outcome of pitting scars and/or lower GI involvement and/or myositis and/or myocarditis was highest among high-titre anti-SMN+ patients: adjusted OR 7.79 (2.33 to 30.45, p=0.002).

CONCLUSIONS

Anti-SMN aAbs were present in 59% of our MCTD cohort. Their presence, especially at high-titres, was associated with a severe systemic sclerosis (scleroderma) phenotype including myositis, myocarditis and lower GI involvement.

255th ENMC workshop: Muscle imaging in idiopathic inflammatory myopathies. 15th January, 16th January and 22nd January 2021 - virtual meeting and hybrid meeting on 9th and 19th September 2022 in Hoofddorp, The Netherlands

The 255th ENMC workshop on Muscle Imaging in Idiopathic Inflammatory myopathies (IIM) aimed at defining recommendations concerning the applicability of muscle imaging in IIM. The workshop comprised of clinicians, researchers and people living with myositis. We aimed to achieve consensus on the following topics: a standardized protocol for the evaluation of muscle images in various types of IIMs; the exact parameters, anatomical localizations and magnetic resonance imaging (MRI) techniques; ultrasound as assessment tool in IIM; assessment methods; the pattern of muscle involvement in IIM subtypes; the application of MRI as biomarker in follow-up studies and clinical trials, and the place of MRI in the evaluation of swallowing difficulty and cardiac manifestations. The following recommendations were formulated: In patients with suspected IIM, muscle imaging is highly recommended to be part of the initial diagnostic workup and baseline assessment. MRI is the preferred imaging modality due to its sensitivity to both oedema and fat accumulation. Ultrasound may be used for suspected IBM. Repeat imaging should be considered if patients do not respond to treatment, if there is ongoing diagnostic uncertainty or there is clinical or laboratory evidence of disease relapse. Quantitative MRI is established as a sensitive biomarker in IBM and could be included as a primary or secondary outcome measure in early phase clinical trials, or as a secondary outcome measure in late phase clinical trials. Finally, a research agenda was drawn up.

Joint and muscle inflammatory disease: A scoping review of the published evidence

OBJECTIVES

Polyarthritis is commonly reported in idiopathic inflammatory myositis patients, but few studies have focused on the overlap of myositis with rheumatoid arthritis which is a difficult diagnosis in the absence of well-defined diagnostic criteria. The primary objective of this scoping review was to map the field of research to explore the potential diagnoses in patients presenting with both myositis and polyarthritis.

METHODS

Two electronic databases (MEDLINE/PubMed® and Web of Science®) were systematically searched using the terms (myositis OR 'inflammatory idiopathic myopathies') AND (polyarthritis OR 'rheumatoid arthritis') without any publication date limit.

RESULTS

Among individual records, 280 reports met inclusion criteria after full-text review. There was heterogeneity in the definition of overlap myositis as well as the characteristics of rheumatoid arthritis. In many studies, key data were lacking; rheumatoid factor status was reported in 56.8% (n=151), anti-citrullinated proteins antibodies status in 18.8% (n=50), and presence or absence of bone erosions in 45.1% (n=120) of the studies. Thirteen different diagnoses were found to associate myositis with polyarthritis: antisynthetase syndrome (29.6%, n=83), overlap myositis with rheumatoid arthritis (16.1%, n=45), drug-induced myositis (20.0%, n=56), rheumatoid myositis (7.5%, n=21), inclusion body myositis (1.8%, n=5), overlap with connective tissue disease (20.0%, n=56), and others (5.0%, n=14).

CONCLUSION

The spectrum of joint and muscle inflammatory diseases encompasses many diagnoses including primitive and secondary myositis associated with RA or arthritis mimicking RA. This review highlights the need for a consensual definition of OM with RA to better individualise this entity from the numerous differential diagnoses.

Subcutaneous tissue involvement in idiopathic inflammatory myopathies: Systematic literature review including three new cases and hypothetical mechanisms

INTRODUCTION

Involvement of subcutaneous tissue in idiopathic inflammatory myopathies (IIM) is poorly known.

METHODS

We conducted a systematic review of the literature regarding panniculitis and lipodystrophy/lipoatrophy in juvenile and adult IIM via PubMed/Medline, Embase and Scopus databases. Three local observations are included in this review. Epidemiological, clinical, paraclinical and therapeutic data were collected.

RESULTS

Panniculitis appears to be more common in adults than in juveniles. It was mainly localised in the upper and lower limbs. Panniculitis improved in most cases with steroids and panniculitis and myositis had a similar course in 83.3% and 72.2% of cases in juveniles and adults, respectively. Lipodystrophy appeared to be more frequent in juveniles and was only observed in dermatomyositis in both juveniles and adults. Lipodystrophy was mainly partial in juveniles and adults. The median time from myositis to the diagnosis of lipodystrophy was 6 years [0-35] and 2.5 years [0-10] in juveniles and adults, respectively. Lipodystrophy was associated with anti-TIF1 gamma auto-antibody positivity, a polycyclic/chronic course of myositis and the occurrence of calcinosis and might be an indicator of poor disease control.

CONCLUSION

Adipose tissue involvement, particularly lipodystrophy, occurs almost exclusively in dermatomyositis. The insidious onset and lack of awareness of the diagnosis may underestimate its prevalence. Larger studies are needed to identify possible risk factors in these patients, to better potential underlying pathophysiological process, in order to discuss potential therapeutic targets.

A novel overlap syndrome: Rheumatoid arthritis, Sjogren's syndrome, antiphospholipid syndrome, and dermatomyositis

Key Clinical Message

This is an extremely rare case that has not been presented or discussed in the literature to the best of our knowledge. The overlap of connective tissue disease is a challenge for physicians and patients, and it needs special care and regular clinical and laboratory follow-up.

Abstract

This report describes a rare case of overlapping connective tissue diseases in a 42-year-old female with rheumatoid arthritis, Sjogren's syndrome, antiphospholipid syndrome, and dermatomyositis. The patient presented with a hyperpigmented erythematous rash, muscle weakness, and pain, highlighting the challenges of diagnosis and treatment that require regular clinical and laboratory follow-up.

Marked Efficacy of a Therapeutic Strategy in a Patient With Necrotizing Myopathy Associated With Anti-signal Recognition Particle (SRP) Autoantibodies

Necrotizing autoimmune myopathy (NAM) is a rare muscular disorder characterized by severe proximal muscle weakness. Risk factors include statin use, malignancy, and connective tissue diseases. The current study presents the first case of NAM in Saudi Arabia in a 26-year-old female who presented with proximal upper and lower limb weakness, dysphagia, dysarthria, and dyspnea with no previous medical or surgical history and was not on medication. Targeted myopathic antibody analysis revealed antibodies to signal recognition particles (SRP), and the serum creatinine kinase level reached 9308 U/L. A diagnosis of NAM was made, and the patient was started on the management plan. We discussed an interesting case progression and adverse effect challenges, as well as the management of these difficult-to-treat conditions.

Myositis autoantibodies detected by line blot immunoassay: clinical associations and correlation with antibody signal intensity

The aim of this study is to assess the relationship between myositis specific (MSA) and myositis associated (MAA) antibodies and diagnosis (including idiopathic inflammatory myopathies [IIM] and other systemic autoimmune diseases [SAID]), and to explore the impact of antibody signal intensity in diagnostic accuracy. We retrospectively reviewed all the serum samples obtained from patients tested for MSA/MAA by line immunoassay (LIA) between 01/01/2018 and 31/12/2020 in Ramón y Cajal University Hospital (Spain). Clinical true positive (CTP) MSAs and MAAs were defined as those patients with IIM or SAID with phenotypes expected of that MSA/MAA. Patients who did not have a phenotype compatible with that antibody were classified as clinical false positive (CFP). One hundred and thirty positive samples were analysed. Forty-six patients (33.38%) were classified as IIM, forty-two (32.3%) as SAID and forty-two (32.3%) as non-IIM/SAID. Among these 130 patients, 164 MSA/MAA were detected. Eighty-five (51.8%) positive MSA/MAA were classified as CTP, and seventy-nine (48.2%) as CFP. Strongly positive antibodies were more frequently CTP (35/47, 74.5%) than weak positives (54/68, 36.8%), (p ˂ 0.001). Antibodies classified as CTP had a higher signal intensity than CFP (36.77 AU vs 20.00 AU, CI95% 7.79-22.09, p ˂ 0.001). The probability of a CFP was associated to negative ANA, low ANA titer, and multiple positive MSA/MAA (p ˂ 0.001). In this study, we confirmed that CFP results using LIA are frequent, and are associated with low signal intensity MSA/MAA, negative ANA, lower titer ANA, and with multiple positive samples.

Scleromyositis: A distinct novel entity within the systemic sclerosis and autoimmune myositis spectrum. Implications for care and pathogenesis

Systemic sclerosis and autoimmune myositis are both associated with decreased quality of life and increased mortality. Their prognosis and management largely depend on the disease subgroups. Indeed, systemic sclerosis is a heterogeneous disease, the two predominant forms of the disease being limited and diffuse scleroderma. Autoimmune myositis is also a heterogeneous group of myopathies that classically encompass necrotizing myopathy, antisynthetase syndrome, dermatomyositis and inclusion body myositis. Recent data revealed that an additional disease subset, denominated "scleromyositis", should be recognized within both the systemic sclerosis and the autoimmune myositis spectrum. We performed an in-depth review of the literature with the aim of better delineating scleromyositis. Our review highlights that this concept is supported by recent clinical, serological and histopathological findings that have important implications for patient management and understanding of the disease pathophysiology. As compared with other subsets of systemic sclerosis and autoimmune myositis, scleromyositis patients can present with a characteristic pattern of muscle involvement (i.e. distribution of muscle weakness) along with multisystemic involvement, and some of these extra-muscular complications are associated with poor prognosis. Several autoantibodies have been specifically associated with scleromyositis, but they are not currently integrated in diagnostic and classification criteria for systemic sclerosis and autoimmune myositis. Finally, striking vasculopathic lesions at muscle biopsy have been shown to be hallmarks of scleromyositis, providing a strong anatomopathological substratum for the concept of scleromyositis. These findings bring new insights into the pathogenesis of scleromyositis and help to diagnose this condition, in patients with subtle SSc features and/or no autoantibodies (i.e. "seronegative" scleromyositis). No guidelines are available for the management of these patients, but recent data are showing the way towards a new therapeutic approach dedicated to these patients.

Tertiary lymphoid structures in the primary tumor site of patients with cancer-associated myositis: A case-control study

Objective

To investigate histologic features of immunological components in the primary tumor site of patients with cancer-associated myositis (CAM) by focusing on tumor-infiltrating lymphocytes (TILs) and tertiary lymphoid structures (TLSs), which play major roles in antitumor immunity.

Methods

Cancer-associated myositis patients were selected from the single-center idiopathic inflammatory myopathy cohort based on the availability of primary tumor specimens obtained before the introduction of immunomodulatory agents. Control cancer subjects without CAM were selected from the cancer tissue repository at a ratio of 1:2 matched for demographics and cancer characteristics of CAM cases. A series of immunohistochemical analyses was conducted using sequential tumor sections. TLS was defined as an ectopic lymphoid-like structure composed of DC-LAMP⁺ mature dendritic cells, CD23⁺ follicular dendritic cells (FDCs) and PNAd⁺ high endothelial venules. TLS distribution was classified into the tumor center, invasive margin, and peritumoral area.

Results

Six CAM patients and 12 matched non-CAM controls were eligible for the study. There was no apparent difference in the density or distribution of TILs between the groups. TLSs were found in 3 CAM patients (50%) and 4 non-CAM controls (33%). TLSs were exclusively located at the tumor center or invasive margin in CAM cases but were mainly found in the peritumoral area in non-CAM controls. FDCs and class-switched B cells colocalized with follicular helper T cells were abundantly found in the germinal center-like area of TLSs from CAM patients compared with those from non-CAM controls.

Conclusion

The adaptive immune response within TLSs in the primary tumor site might contribute to the pathogenic process of CAM.

Management of Cancer-Associated Myositis

Purpose of the Review

Cancer-associated myositis (CAM) is defined as when cancer appears within 3 years of myositis onset. Dermatomyositis and seronegative immune–mediated necrotizing myopathy are the phenotypes mostly related to cancer. In general, treatment principles in myositis patients with and without CAM are similar. However, some aspects of myositis management are particular to CAM, including (a) the need for a multidisciplinary approach and a close relationship with the oncologist, (b) the presence of immunosuppressive and antineoplastic drug interactions, and (c) the role of the long-term immunosuppressive therapy as a risk factor for cancer relapse or development of a second neoplasm. In this review, we will also discuss immunotherapy in patients treated with checkpoint inhibitors as a treatment for their cancer.

Recent Findings

Studies on cancer risk in patients treated with long-term immunosuppressive drugs, in autoimmune diseases such as systemic lupus erythematosus or rheumatoid arthritis, and in solid organ transplant recipients have shed some light on this topic. Immunotherapy, which has been a great advance for the treatment of some types of malignancy, may be also of interest in CAM, given the special relationship between both disorders.

Summary

Management of CAM is a challenge. In this complex scenario, therapeutic decisions must consider both diseases simultaneously.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40674-022-00197-2.

Clinical Significance of Antinucleolar Antibodies: Biomarkers for Autoimmune Diseases, Malignancies, and others

Nucleolar staining is one of the standard patterns in immunofluorescence antinuclear antibodies (ANA), seen in 5-9% of ANA in various conditions. Antinucleolar antibodies (ANoA) are classified into 3 patterns in the International Consensus on ANA Patterns (ICAP) classification; AC-8 homogeneous pattern, AC-9 clumpy pattern, and AC-10 punctate pattern. Specificities known to show AC-8 include anti-Th/To, -PM-Scl, -nucleophosmin/B23, -nucleolin/C23, -No55, and others. AC-9 is seen by anti-fibrillarin/U3RNP and AC-10 by anti-RNA polymerase I and hUBF/NOR-90. ANoA has been classically known to be associated with scleroderma (SSc) and the characterization of nucleolar antigens identified several autoantigens recognized by SSc autoantibodies. The clinical association of anti-Th/To, PM-Scl, fibrillarin/U3RNP, and RNA polymerase I with SSc or SSc-overlap syndrome is well established, and commercial assays are developed. Anti-hUBF/NOR90, nucleophosmin/B23, and nucleolin/C23 are known for decades and reported in systemic autoimmune rheumatic diseases (SARDs), malignancies, graft versus host disease (GVHD), and others; however, their clinical significance remains to be established.

Current and new targets for treating myositis

As treatment of refractory idiopathic inflammatory myopathies (IIM) has been challenging, there is growing interest in assessing new therapies that target various pathways implicated in the pathogenesis of IIM. In the largest clinical trial to date, rituximab was studied in adult and juvenile myositis, but the primary outcome was not met despite 83 percent of subjects with refractory myositis meeting the definition of improvement. The U.S. Food and Drug Administration (FDA) has recently granted approval to Octagam 10% immune globulin intravenous (IVIg), for the treatment of adult dermatomyositis based on impressive results from a double-blind placebo-controlled trial. Anti-tumor necrosis factor (anti-TNF) utility in IIM is not recommended and recent reports suggest this therapy may induce systemic autoimmune disease including myositis. Further, anti-IL6 therapy cannot be recommended as a recent trial of tocilizumab failed to reach its primary endpoint. Further studies are needed to assess the role of newer therapies such as abatacept (inhibition of T cell co-stimulation), sifalimumab (anti-IFNα), Janus kinase [JAK] inhibitors, apremilast (phosphodiesterase 4 inhibitor), and KZR-616 (selective inhibitor of the immunoproteasome) given their biological plausibility and encouraging recent small-case series results. The future of IIM therapy will depend on exploring biomarkers implicated in the etiopathogenesis of IIM, improvements in myositis classification based on serological and histopathological features, and well-designed controlled clinical trials using validated consensus outcome measures.

Impact of dysphagia and its severity on long-term survival and swallowing function outcomes in patients with idiopathic inflammatory myopathies other than inclusion body myositis

OBJECTIVE

To investigate the impact of dysphagia on long-term survival and swallowing function outcomes in patients with idiopathic inflammatory myopathy other than inclusion body myositis.

METHODS

We retrospectively evaluated consecutive patients with idiopathic inflammatory myopathy other than inclusion body myositis to investigate the impact of dysphagia and its severity assessed using the Food Intake LEVEL Scale on survival and swallowing function outcomes. Time-to-event analyses were used, including Kaplan-Meier curves with log-rank (trend) test, cumulative incidence with Gray's test, and Cox proportional hazards models.

RESULTS

Of the 254 patients, 26 were dysphagic, including eight severe (Food Intake LEVEL Scale [FILS] score 2, 3) and six most severe (FILS score 1) cases; 210 were non-dysphagic, and 18 were indeterminate cases. During the 5 years after myositis diagnosis, 15 (57.7%) dysphagic and 31 (14.8%) non-dysphagic patients died, and dysphagic patients had significantly shorter survival. However, multivariate analysis showed that shorter survival was significantly associated with baseline age-adjusted Charlson Comorbidity Index (hazard ratio [HR] 1.57, 95% confidence interval [CI] 1.36-1.82]), but not with dysphagia (HR 1.46, 95% CI 0.69-3.10). Dysphagia severity was significantly associated with delayed recovery of dysphagia. In 20 non-severe or severe dysphagic cases, 19 restored swallowing function within 1 year. The most severe cases had a significantly higher cumulative probability of death before recovery from dysphagia than severe cases.

CONCLUSION

The poor survival of dysphagic myositis patients was largely confounded by advanced age and comorbid malignancies. However, patients with the most severe dysphagia had a significantly worse swallowing function and survival prognosis than those with milder dysphagia.

Clinical, Serological, and Genetic Characteristics of a Hungarian Myositis-Scleroderma Overlap Cohort

Overlap myositis is a distinct subgroup of idiopathic inflammatory myositis (IIM) with various clinical phenotypes. The aim of this study was to determine the clinical, serological, and genetic features of systemic sclerosis (SSc)-IIM overlap patients. It was a retrospective study using clinical database of 39 patients, fulfilling both the criteria of SSc and IIM. 56.4% of the patients had limited cutaneous, 43.6% had diffuse cutaneous SSc, whereas 7.7% of the patients had dermatomyositis and 92.3% polymyositis. The two diseases occurred simultaneously in 58.97%, while 10.26% in myositis and 30.77% in scleroderma were initially diagnosed. The frequencies of organ involvement were interstitial lung disease 71.8%, dysphagia 66.7%, cardiac involvement 41%, pulmonary arterial hypertension (PAH) 30.8%, and renal involvement 12.8%, respectively. The presence of human leukocyte antigen (HLA) − DRB1∗03 and DQA1∗051∗01 alleles were significantly higher in the overlap patients than in healthy controls (82.35% vs. 27.54%; p < 0.0001 and 88.24% vs. 30.16; p < 0.0001). Certain clinical parameters, such as fever at diagnosis (41.67% vs. 7.41%, p = 0.0046), cardiac involvement (83.33% vs. 22.22%, p = 0.0008), subcutaneous calcinosis (41.66 vs. 11.11, p = 0.01146), and claw hand deformity (25% vs. 11.11%, p = 0.00016) were significantly associated with the presence of PAH. Upon comparison, the overlap patients and anti-Jo-1 positive antisynthetase patients showed similarities in terms of genetic results and major clinical features; however, SSc-IIM overlap patients could be distinguished with higher erythrocyte sedimentation rate (ESR) level, more frequent presence of Raynaud's phenomenon (p < 0.0001; OR: 20.00), dysphagia (p < 0.0001; OR: 15.63), and infrequent livedo reticularis (p < 0.01; OR: 0.11). SSc-IIM overlap myositis is a unique group within IIM-s possessing characteristic clinical features.

The Role of Quantitative and Semi-quantitative [18F]FDG-PET/CT Indices for Evaluating Disease Activity and Management of Patients With Dermatomyositis and Polymyositis

Idiopathic inflammatory myopathies (IIM) are considered systemic diseases involving different organs and some subtypes are associated with increased cancer risk. In this review, we provide a comprehensive summary of the current use and potential applications of (semi-)quantitative [18F]FDG-PET/CT indices in patients with IIM focusing on dermatomyositis and polymyositis. Visual interpretation and (semi-)quantitative [18F]FDG-PET indices have a good overall performance to detect muscle activity but objective, robust and standardized interpretation criteria are currently lacking. [18F]FDG-PET/CT is a suitable modality to screen for malignancy in patients with myositis and may be a promising tool to detect inflammatory lung activity and to early identify patients with rapidly progressive lung disease. The latter remains to be determined in large, prospective comparative trials.

Incidence of systemic autoimmune myopathies and their risk of cancer in Leeds, UK: an 11-year epidemiological study

Objectives

The aims were to identify all incident adult cases of systemic autoimmune myopathies (SAMs) in the city of Leeds, UK, and to estimate the risk of cancer in SAMs as compared with the general population.

Methods

Cases of SAMs were ascertained by review of all muscle biopsy reports from the Neuropathology Laboratory. A review of medical records was undertaken for each case to review the clinical diagnosis and collect epidemiological data such as age, ethnicity, sex and comorbidities, including cancer. Leeds denominator population numbers were publicly obtainable.

Results

A total of 206 biopsy reports were identified and, after review, 50 incident cases were included in the study between June 2010 and January 2021. Of the 50 cases, 27 were male and 23 were female. The mean incidence rate of SAMs in Leeds throughout the study period was 7.42/1 000 000 person-years. The proportion of SAMs cases with a confirmed malignancy was 22%. Compared with the general population, the relative risk of cancer was significantly greater in the SAMs population (31.56; P < 0.01).

Conclusions

The incidence rate of SAMs in Leeds was consistent with data from previous literature; however, disagreement exists between different methods of SAMs case inclusion due to varying clinical criteria and definitions. SAMs are associated with an increased risk of cancer, but the pathogenesis of this relationship still requires investigating. This study supports the practice of malignancy screening and long-term surveillance in patients with SAMs.

Muscle Biopsy: A Requirement for Precision Medicine in Adult-Onset Myopathy

Muscle biopsy is a fundamental procedure to assist the final diagnosis of myopathy. With the recent advances in molecular diagnosis, serology tests, and mechanism-based classification in myopathy, the précised diagnosis for myopathy required the applications of multiple tools. This study intends to reappraise the benefit of muscle biopsy in adult-onset myopathy under the setting of an optimized muscle biopsy protocol and comprehensive serology tests. A one-group pretest-posttest study design was used. The pre- and post-biopsy diagnoses and treatments in 69 adult patients were compared. Muscle biopsy yielded 85.5% of definitive diagnoses, including changes in pre-biopsy diagnoses (40.6%) and narrowing down the suspicious myopathies (49.3%). The demographic data and clinical parameters between the group “with change” and “without change” after biopsy were not different. Among those with changes in diagnosis, 39.3% also had a corresponding shift in treatment, which benefits the patients significantly. Regarding the most common adult-onset myopathy, idiopathic inflammatory myopathy (IIM), 41% of patients with pre-biopsy diagnosis as IIM had changes in their IIM subtype diagnosis, and 53% was finally not IIM after muscle biopsy. Although there have been advances in molecular diagnosis recently, muscle biopsy still undoubtedly critically guided the diagnosis and treatment of adult-onset myopathy in the era of precision medicine.

Hsp90 Levels in Idiopathic Inflammatory Myopathies and Their Association With Muscle Involvement and Disease Activity: A Cross-Sectional and Longitudinal Study

Background

Heat shock proteins (Hsp) are chaperones playing essential roles in skeletal muscle physiology, adaptation to exercise or stress, and activation of inflammatory cells. We aimed to assess Hsp90 in patients with idiopathic inflammatory myopathies (IIM) and its association with IIM-related features.

Methods

Hsp90 plasma levels were analyzed in a cross-sectional cohort (277 IIM patients and 157 healthy controls [HC]) and two longitudinal cohorts to assess the effect of standard-of-care pharmacotherapy (n=39 in early disease and n=23 in established disease). Hsp90 and selected cytokines/chemokines were measured by commercially available ELISA and human Cytokine 27-plex Assay.

Results

Hsp90 plasma levels were increased in IIM patients compared to HC (median [IQR]: 20.2 [14.3–40.1] vs 9.8 [7.5–13.8] ng/mL, p<0.0001). Elevated Hsp90 was found in IIM patients with pulmonary, cardiac, esophageal, and skeletal muscle involvement, with higher disease activity or damage, and with elevated muscle enzymes and crucial cytokines/chemokines involved in the pathogenesis of myositis (p<0.05 for all). Plasma Hsp90 decreased upon pharmacological treatment in both patients with early and established disease. Notably, Hsp90 plasma levels were slightly superior to traditional biomarkers, such as C-reactive protein and creatine kinase, in differentiating IIM from HC, and IIM patients with cardiac involvement and interstitial lung disease from those without these manifestations.

Conclusions

Hsp90 is increased systemically in patients with IIM. Plasma Hsp90 could become an attractive soluble biomarker of disease activity and damage and a potential predictor of treatment response in IIM.

Autoantibodies against Four-and-a-Half-LIM Domain 1 (FHL1) in Inflammatory Myopathies: Results from an Australian Single-Center Cohort

Objectives

To determine the prevalence and associations of autoantibodies targeting a muscle-specific autoantigen, four-and-a-half-LIM-domain 1 (FHL1), in South Australian patients with histologically-confirmed idiopathic inflammatory myopathies (IIM) and in patients with SSc.

Material and methods

Sera from patients with IIM (n = 267) from the South Australian Myositis Database (SAMD), SSc (n = 174) from the Australian Scleroderma Cohort Study (ASCS) and healthy controls (HC, n = 100) were analysed for anti-FHL1 autoantibodies by Enzyme-Linked ImmunoSorbent Assay (ELISA).

Results

Autoantibodies to FHL1 were more frequent in patients with IIM (37/267, 13.8%) compared with SSc (12/174, 7%) (P < 0.02) and HC (2/100, 2%) (P < 0.001). The most common IIM subtypes among FHL1⁺ IIM patients were (32%) and IBM (2/37, 32%). No statistically significant differences in muscular or extra-muscular manifestations of IIM were found when comparing patients who were anti-FHL1⁺ with their anti-FHL1^– counterparts. In 29/37 (78%) anti-FHL1⁺ patients, no myositis-specific autoantibodies (MSA) were present. In FHL1⁺ muscle biopsies, there was less frequent infiltration by CD45⁺ cells (P = 0.04). There was a trend for HLA alleles DRB1*07 and DRB1*15 to be more frequent in anti-FHL1⁺ compared with anti-FHL1^– patients (9/25 vs 19/113, P = 0.09 and 8/25 vs 15/114, P = 0.09, respectively).

Conclusions

We report a substantial prevalence (13.8%) of anti-FHL1 autoantibodies in a large cohort of patients with histologically confirmed IIM; 75% of these cases did not have a detectable myositis-specific autoantibody. Anti-FHL1 autoantibodies were also detected in a subgroup of patients with SSc (7%), indicating that anti-FHL1 autoantibodies may not be myositis-specific. The trend towards an HLA-DR association might indicate a specific immune response to the FHL1 protein.

Cancer screening in idiopathic inflammatory myopathies: Ten years experience from a single center

OBJECTIVE

There is a well-recognized association between cancer and myositis, so cancer screening at diagnosis is recommended. We aim to report the results of our cancer screening strategy and to ascertain the reliability of using PET/CT to identify cancer-associated myositis (CAM) in a large cohort of patients with myositis from a single center over 10 years.

METHODS

This retrospective observational study included all patients diagnosed with any type of myositis except for inclusion body myositis. Cancer screening strategy was individualized according to clinical and serological data, including PET/CT as the main test to detect occult cancer (OC). Procedures derived from a positive PET/CT were registered. Qualitative data expressed as percentages, and quantitative data as the median with the interquartile range were analyzed. A ROC curve was used to estimate the reliability of PET/CT for CAM diagnosis.

RESULTS

Seventy-seven out of 131 patients underwent a PET/CT for OC screening. The performance of the PET/CT in patients with myositis at disease onset yielded an area under the curve ROC of 0.87 (0.73-0.97) for CAM diagnosis. Invasive procedures in 7 (9%) patients without a final diagnosis of cancer did not cause derived complications. Patients not evaluated for OC did not develop cancer after a median follow-up of 3.3 years (1.7-6.7).

CONCLUSION

Cancer screening strategy should be individualized. PET/CT at myositis onset seems to be an efficient approach to rule out CAM. This practice does not seem to significantly increase harm to patients related to the additional tests needed to clarify inconclusive results.

Myositis, Osteomyelitis and a Parasymphyseal Stress Fracture in a Paediatric Patient

The limping child and painful hip are common presentations in many paediatric emergency units. Typically caused by mild self-limiting events, less commonly, they may be implicated in one of a group of inflammatory myopathies, or myositis. Diagnosis of this condition can be extremely difficult, and is aided by thorough clinical assessment, radiological imaging, and extensive blood serum testing. Myositis with associated osteomyelitis and a pathological fracture is an incredibly rare finding, described in this case report in a seven-year-old child. 

[Clinical and immunological characteristics of 88 cases of overlap myositis]

OBJECTIVE

To investigate the clinical and immunological characteristics of overlap myositis (OM) patients.

METHODS

The data of 368 patients with idiopathic inflammatory myopathies (IIMs) admitted to Peking University People's Hospital from January 2004 to August 2020 were analyzed retrospectively, including demographic characteristics, clinical characteristics (including fever, Gottron' s sign/papules, Heliotrope rash, V-sign, Shawl sign, Mechanic' s hands, skin ulceration, periungual erythema, subcutaneous calcinosis, dysphagia, myalgia, myasthenia, arthritis, Raynaud' s phenomenon, interstitial lung disease, pulmonary hypertension and myocardial involvement), laboratory characteristics, immunological characteristics [including antinuclear antibodies, rheumatoid factors, myositis-associated autoantibodies (MAAs) and myositis-specific autoantibodies (MSAs)] and survival. The clinical and immunological characteristics and prognostic differences of OM and non-OM were compared. The Kaplan-Meier and Log Rank methods were used to analyze the survival.

RESULTS

A total of 368 patients were included. 23.9% (88/368) of IIMs patients were OM patients. Among the 88 OM patients, 85.2% (75/88) of them were female, and the median interval between disease onset and diagnosis was 13.5 months. The incidence of overlapped connective tissue diseases in the OM patients was dermatomyositis (DM) in 60.2%, polymyositis (PM) in 3.4%, immune-mediated necrotizing myopathy (IMNM) in 2.3% and anti-synthetase syndrome (ASS) in 34.1%. Compared with the non-OM patients, the proportion of the females in the OM patients was higher (85.2% vs. 72.1%, P=0.016), the OM patients had longer disease duration [13.5(4.5, 48.0) months vs. 4.0(2.0, 12.0) months, P < 0.001]. As for clinical characteristics, compared with the non-OM patients, the incidence of V-sign (25.0% vs. 44.6%, P=0.001) and periungual erythema (8.0% vs. 19.6%, P=0.013) were lower; the incidence of Raynaud's phenomenon (14.8% vs. 1.8%, P < 0.001), interstitial pneumonia (88.6% vs. 72.1%, P=0.001), pulmonary hypertension (22.7% vs. 7.5%, P < 0.001) and myocardial involvement (18.2% vs. 9.3%, P=0.033) were higher. As for immunological characteristics, compared with the non-OM patients, the incidence of elevated aspartate aminotransferase (AST) (31.8% vs. 45.0%, P=0.035) was lower and elevated C-reactive protein (CRP) (58.0% vs. 44.6%, P=0.037) was higher; the positive rates of antinuclear antibodies (ANA) (85.1% vs. 63.4%, P=0.001) and rheumatoid factors (RF) (40.2% vs. 17.8%, P < 0.001) and anti-Ro-52 (71.6% vs. 56.1%, P=0.038) in serum were higher. There was no significant difference in the survival between the OM patients and non-OM patients.

CONCLUSION

Pulmonary hypertension and myocardial involvement were frequently observed in OM.

Idiopathic inflammatory myopathies

Idiopathic inflammatory myopathies (IIM), also known as myositis, are a heterogeneous group of autoimmune disorders with varying clinical manifestations, treatment responses and prognoses. Muscle weakness is usually the classical clinical manifestation but other organs can be affected, including the skin, joints, lungs, heart and gastrointestinal tract, and they can even result in the predominant manifestations, supporting that IIM are systemic inflammatory disorders. Different myositis-specific auto-antibodies have been identified and, on the basis of clinical, histopathological and serological features, IIM can be classified into several subgroups - dermatomyositis (including amyopathic dermatomyositis), antisynthetase syndrome, immune-mediated necrotizing myopathy, inclusion body myositis, polymyositis and overlap myositis. The prognoses, treatment responses and organ manifestations vary among these groups, implicating different pathophysiological mechanisms in each subtype. A deeper understanding of the molecular pathways underlying the pathogenesis and identifying the auto-antigens of the immune reactions in these subgroups is crucial to improving outcomes. New, more homogeneous subgroups defined by auto-antibodies may help define disease mechanisms and will also be important in future clinical trials for the development of targeted therapies and in identifying biomarkers to guide treatment decisions for the individual patient.

Myositis-Specific Antibodies and Myositis-Associated Antibodies in Patients With Idiopathic Inflammatory Myopathies From the PANLAR Myositis Study Group

BACKGROUND

Dermatomyositis (DM) and polymyositis (PM) are forms of idiopathic inflammatory myopathies (IIMs), which are associated with the production of autoantibodies that are useful in the diagnosis and prognosis of the disease.

OBJECTIVE

The aim of this study was to determine the frequency of antinuclear autoantibodies (ANAs), myositis-specific autoantibodies (MSAs), and myositis-associated autoantibodies (MAAs) in 6 Latin American countries.

METHODS

Two hundred ten patients with IIM were included in this cross-sectional study from 2014 to 2017: 112 from Mexico, 46 from Colombia, 20 from Peru, 16 from the Dominican Republic, 10 from Argentina, and 6 from Guatemala. Antinuclear autoantibodies were detected by indirect immunofluorescence on HEp-2 cells. MSAs and MAAs were tested by a line immunoassay method. Mann-Whitney U and χ2 tests were used for statistical analysis.

RESULTS

Of the 210 IIM patients, 139 (66.2%) had DM, 59 (28%) PM, and 12 (5.7%) juvenile DM. The mean age was 43.5 (6-79 years); 158 (75.2%) were female, and 52 (24.8%) were male. The overall frequency of ANA was 60%. The most frequent patterns were fine speckled (AC-4) (78.3%) and cytoplasmic (AC-19) (6.45%). The most frequent MSA were anti-Mi-2 (38.5%) and anti-Jo-1 (11.9%). Anti-Mi-2 was more frequent in patients from Colombia (40.1%). The MAA more frequent were anti-Ro-52/TRIM21 (17.6%) and anti-PM-Scl75 (7.5%).

CONCLUSIONS

This is the first study of ANA, MSA, and MAA in patients from 6 countries from the Panamerican League against Rheumatism myositis study group. We observed a general prevalence of 60% of ANA. In relation to MSA and MAA, anti-Mi-2 was the more frequent (38.5%).

Association between clinical phenotypes of dermatomyositis and polymyositis with myositis-specific antibodies and overlap systemic autoimmune diseases

The aim of this study was to evaluate the association between clinical phenotypes of dermatomyositis (DM) and polymyositis (PM) with myositis-specific antibodies (MSAs), and overlap diagnosis of systemic autoimmune diseases.This cross-sectional study was conducted on 67 patients with DM and 27 patients with PM recruited from a regional hospital in southern Taiwan. Clinical phenotypes of DM and PM were assessed and MSAs were measured using a commercial line blot assay. The association of clinical phenotypes of DM and PM with MSAs and overlap diagnosis of systemic autoimmune diseases was performed using univariate and multiple logistic regression analyses.Clinically, patients with DM and PM and overlap diagnosis of systemic sclerosis were associated with a higher risk of interstitial lung diseases (ILDs) (odds ratio [OR] = 6.73; P = .048), Raynaud phenomenon (OR = 7.30; P = .034), and malignancy (OR = 350.77; P = .013). The risk of malignancy was also associated with older age (OR 1.31; P = .012), and male patients were associated with a higher risk of fever. For MSAs, anti-aminoacyl-tRNA synthetase antibodies were associated with ILD, antinuclear antibody were associated with a lower risk of arthritis, anti-transcription intermediary factor 1-gamma antibodies were associated with milder symptoms of muscle weakness, anti-Ku antibodies were associated with overlap diagnosis of systemic lupus erythematosus, and anti-Ro52 antibodies were associated with the development of Raynaud phenomenon and Sjögren syndrome.MSAs and overlap diagnosis of systemic sclerosis were significantly associated with clinical phenotypes of DM and PM. Physicians should be vigilant for malignancy in older DM and PM patients with overlap diagnosis of systeic sclerosis. The possibility of developing ILD in patients with overlap diagnosis of systemic sclerosis or serum positivity of anti-aminoacyl-tRNA synthetase antibodies should be considered.

Biomarker und Histologie bei idiopathischen inflammatorischen Myopathien

Die idiopathischen inflammatorischen Myopathien (IIM) sind eine Gruppe entzündlicher Muskelerkrankungen für deren Diagnosestellung, Verlaufsbeurteilung, Prognoseabschätzung und Risikostratifizierung Biomarker eine jeweils essentielle Rolle spielen. Biomarker in diesem Kontext können sowohl „herkömmliche“ serologische Marker wie Muskelenzyme oder Autoantikörper, histologische Marker wie entitätsspezifische inflammatorische Muster, aber auch genomische und genetische Marker sein. Der vorliegende Artikel gibt einen Überblick über bewährte und innovative Marker.

Polymyositis: is there anything left? A retrospective diagnostic review from a tertiary myositis centre

OBJECTIVE

The current classification criteria for idiopathic inflammatory myopathy (IIM) retain PM as a major disease subgroup. However, evolution in the understanding of IIM has suggested that many of these patients could be better described as having an alternative diagnosis. In the present study, we apply the latest understanding of IIM subtyping to retrospectively review PM diagnoses in a large cohort of IIM patients.

METHODS

Within a previously reported cohort of 255 patients from a UK tertiary myositis clinic, 37 patients classified as PM according to both the EULAR/ACR IIM criteria and expert opinion were identified. Clinical data and complementary tests were reviewed, and consensus decisions regarding final classification were reached in each case.

RESULTS

Nine (9/37, 24.3%) patients remained classified as PM, 3.5% (9/255) of the original cohort; these PM patients were seronegative for myositis antibodies, responsive to immunosuppression, and in 4/7 (57.1%) patients where muscle biopsy was performed had HLA-1 upregulation and endomysial inflammatory infiltrates. Immune-mediated necrotizing myopathy (5/37, 13.5%) and connective tissue disease overlap myositis (7/37, 19%) were the main alternative diagnoses. The remaining patients were diagnosed as: unspecified myopathy (6/37, 16%), dermatomyositis (2/37, 5%), cancer-associated myopathy (3/37, 8.1%), and non-inflammatory myopathy (1/37, 3%, myofibrillar myopathy). Four patients (4/37, 10%) had insufficient data available to confidently reclassify.

CONCLUSION

Our study confirms that PM can now be considered a rare IIM subgroup. A thorough examination, complete myositis autoantibody panel, and careful interpretation of the biopsy results is recommended to confirm the correct IIM sub-type.

Recognising the spectrum of scleromyositis: HEp-2 ANA patterns allow identification of a novel clinical subset with anti-SMN autoantibodies

Objective

To describe systemic sclerosis (SSc) with myopathy in patients without classic SSc-specific and SSc-overlap autoantibodies (aAbs), referred to as seronegative scleromyositis.

Methods

Twenty patients with seronegative scleromyositis diagnosed by expert opinion were analysed retrospectively for SSc features at myositis diagnosis and follow-up, and stratified based on HEp-2 nuclear patterns by indirect immunofluorescence (IIF) according to International Consensus of Autoantibody Patterns. Specificities were analysed by protein A−assisted immunoprecipitation. Myopathy was considered an organ involvement of SSc.

Results

SSc sine scleroderma was a frequent presentation (45%) at myositis diagnosis. Myositis was the most common first non-Raynaud manifestation of SSc (55%). Lower oesophagal dysmotility was present in 10 of 11 (91%) investigated patients. At follow-up, 80% of the patients met the American College of Rheumatology/EULAR SSc classification criteria. Two-thirds of patients had a positive HEp-2 IIF nuclear pattern (all with titers ≥1/320), defining three novel scleromyositis subsets. First, antinuclear antibody (ANA)-negative scleromyositis was associated with interstitial lung disease (ILD) and renal crisis. Second, a speckled pattern uncovered multiple rare SSc-specific aAbs. Third, the nuclear dots pattern was associated with aAbs to survival of motor neuron (SMN) complex and a novel scleromyositis subset characteriszed by calcinosis but infrequent ILD and renal crisis.

Conclusions

SSc skin involvement is often absent in early seronegative scleromyositis. ANA positivity, Raynaud phenomenon, SSc-type capillaroscopy and/or lower oesophagal dysmotility may be clues for scleromyositis. Using HEp-2 IIF patterns, three novel clinicoserological subsets of scleromyositis emerged, notably (1) ANA-negative, (2) ANA-positive with a speckled pattern and (3) ANA-positive with nuclear dots and anti-SMN aAbs.

Idiopathische inflammatorische Myopathien: Aktuelles zu Diagnose und Klassifikation

Auf dem Sektor der Kollagenosen ist der wissenschaftliche Fortschritt bei der Myositis in den letzten 15–20 Jahren bemerkenswert. Durch kontinuierliche Forschung und intensive Vernetzung der Myositis-Experten ist es gelungen, neue Untergruppen zu identifizieren und somit für die Prognose wichtige Organmanifestationen rechtzeitig zu erkennen. Vor dem Hintergrund dieser Neuerungen verfolgt diese Übersichtsarbeit sowohl das Ziel, möglichst alle Facetten der Erkrankung zu präsentieren, als auch die moderne Einteilung der idiopathischen inflammatorischen Myopathien zu erläutern. Außerdem werden die neuen Klassifikationskriterien vorgestellt, die die Kriterien von Bohan und Peter aus dem Jahr 1975 abgelöst haben. Im Artikel werden ihre Stärken und Schwächen sowie ihr Optimierungspotenzial diskutiert.

The aetiopathogenic significance, clinical relevance and therapeutic implications of vasculopathy in idiopathic inflammatory myopathy

It is 120 years since 'angiomyositis' was included alongside 'polymyositis' and 'dermatomyositis' in an attempt to propose a taxonomy that reflected the major clinical characteristics of idiopathic inflammatory myopathy (IIM). Endothelial injury, perivascular inflammation and capillary loss are important histological findings in affected tissues in IIM. Overt vascular clinical features including RP and abnormal nailfold capillaroscopy (NC) are also common in IIM. Despite the presence of endothelial injury, perivascular inflammation and capillary loss in affected tissues in IIM, and the presence of clinical features such as RP and NC abnormalities, the pathogenic and therapeutic implications of vasculopathy in IIM have been somewhat overlooked. RP and NC abnormalities are not always present, providing a valuable opportunity to explore aetiopathogenic factors driving vasculopathy within autoimmune rheumatic disease. The present review examines the aetiopathogenic, prognostic and therapeutic significance of vasculopathy in IIM. We describe the prevalence and clinical relevance of vasculopathy in IIM, and consider how vasculopathy may be better utilized to support improved IIM diagnosis and disease classification. Areas of unmet research need are highlighted where relevant.

Long-term efficacy of adding intravenous immunoglobulins as treatment of refractory dysphagia related to myositis: a retrospective analysis

OBJECTIVE

Dysphagia is a life-threating manifestation of idiopathic inflammatory myopathies (IIM). However, we lack a univocal protocol for its treatment. The aim of this retrospective analysis was to evaluate the effectiveness of a step-up strategy by adding a 1-day pulse of IVIGs to immunosuppressants in IIM patients with refractory dysphagia diagnosed by Eating Assessment Tool (EAT)-10 and fibreoptic endoscopic evaluation of swallowing (FEES).

METHODS

Dysphagia was defined as a pharyngo-oesophageal disturbance associated with EAT-10 score ≥3 and at least one FEES abnormality among propulsion failure, solid or liquid stasis. Eighteen out of 154 IIM patients had FEES-confirmed dysphagia and underwent 1 day IVIG 2 g/kg repeated 1 month apart for 3 months, because of dysphagia refractory to high-dose glucocorticoids with methotrexate and/or azathioprine. Clinical characteristics along with myositis-specific antibodies and muscle histopathological findings were studied in FEES-dysphagia IIM and IIM control patients.

RESULTS

After three monthly doses of IVIG, EAT-10 score dropped with complete recover of defective propulsion and progressive decrease in percentage of both solid and liquid stasis. At 52-weeks' follow-up, reached in 12 patients, all these parameters were stable or further improved. An improvement in manual muscle strength test and a steroid-sparing effect of IVIG were also observed. Anti-PM/Scl 75/100 antibodies were much more frequent in the FEES-dysphagia group, while anti-Jo1 antibody was rarely detected.

CONCLUSION

Our treatment schedule with 2 g/kg IVIG was effective for IIM-associated refractory dysphagia assessed by the combination of EAT-10 and FEES. These findings need to be prospectively tested in a larger cohort of IIM patients.

Intravenous immunoglobulins as first-line treatment in idiopathic inflammatory myopathies: a pilot study

OBJECTIVES

We explored efficacy and safety of IVIg as first-line treatment in patients with an idiopathic inflammatory myopathy.

METHODS

In this investigator-initiated phase 2 open-label study, we included 20 adults with a newly diagnosed, biopsy-proven idiopathic inflammatory myopathy, and a disease duration of less than 9 months. Patients with IBM and prior use of immunosuppressants were excluded. The standard treatment regimen consisted of IVIg (Privigen) monotherapy for 9 weeks: a loading dose (2 g/kg body weight) and two subsequent maintenance doses (1 g/kg body weight) with a 3-week interval. The primary outcome was the number of patients with at least moderate improvement on the 2016 ACR/EULAR Total Improvement Score. Secondary outcomes included time to improvement, the number of patients requiring rescue medication and serious adverse events.

RESULTS

We included patients with DM (n = 9), immune-mediated necrotizing myopathy (n = 6), non-specific myositis/overlap myositis (n = 4) and anti-synthetase syndrome (n = 1). One patient was excluded from analyses because of minimal weakness resulting in a ceiling effect. Eight patients (8/19 = 42.0%; Clopper-Pearson 95% CI: 19.6, 64.6) had at least moderate improvement by 9 weeks. Of these, six reached improvement by 3 weeks. Seven patients required rescue medication due to insufficient efficacy and prematurely ended the study. Three serious adverse events occurred, of which one was pulmonary embolism.

CONCLUSION

First-line IVIg monotherapy led to at least moderate improvement in nearly half of patients with a fast clinical response in the majority of responders.

TRIAL REGISTRATION

Netherlands Trial Register identifier, NTR6160.

Autoantibody profiles delineate distinct subsets of scleromyositis

OBJECTIVE

Scleromyositis remains incompletely characterized owing in part to its heterogeneity. The purpose of this study was to explore the role of autoantibody profiles to define subsets of scleromyositis.

METHODS

Subjects with scleromyositis from a prospective cohort were divided into 3 groups based on autoantibody profiles: subjects with SSc-specific autoantibodies (anti-centromere, -topoisomerase 1, -RNA polymerase III, -Th/To, -fibrillarin), subjects with SSc-overlap autoantibodies (anti-PM/Scl, -U1RNP, -Ku), and subjects without SSc-related autoantibodies. Clinical features, laboratory tests, and histopathological findings were retrieved and compared between groups.

RESULTS

Of 42 scleromyositis subjects (79% female, mean age at diagnosis 55 years, mean disease duration 3.5 years), 8 (19%) subjects had SSc-specific autoantibodies, 14 (33%) SSc-overlap autoantibodies and 20 (48%) had no SSc-related autoantibodies. One-third had no skin involvement, a finding more frequent in the SSc-overlap subjects and those without SSc-related autoantibodies. Proximal and distal weakness was common and head drop/bent spine was found in 50% of the SSc-specific and 35% of the subjects without SSc-related autoantibodies. Of note, the group without SSc-related autoantibodies had the only cases of severe cardiac systolic dysfunction (n = 1) and scleroderma renal crisis (n = 1), as well as 3 out of the 4 cancers and 3 out of the 4 deaths.

CONCLUSION

In this carefully phenotyped series of scleromyositis subjects, absence of SSc-related autoantibodies was common and associated with distinct features and poor prognosis. Future studies are needed to validate these results and possibly identify novel autoantibodies or other biomarkers associated with scleromyositis.

Histopathological features of systemic sclerosis-associated myopathy: A scoping review

BACKGROUND

Scleromyositis (SM) is an emerging subset of myositis associated with features of systemic sclerosis (SSc) but it is currently not recognized as a distinct histopathological subset by the European NeuroMuscular Center (ENMC). Our aim was to review studies reporting muscle biopsies from SSc patients with myositis and to identify unique histopathological features of SM.

METHODS

A scoping review was conducted and included all studies reporting histopathological findings in SSc patients with myositis searching the following databases: PubMed, MEDLINE, EMBASE, CINAHL and EBM-Reviews. Clinical, serological, and histopathological data were extracted using a standardized protocol.

RESULTS

Out of 371 citations, 77 studies that included 559 muscle biopsies were extracted. Fifty-seven percent (n = 227/400) had inflammatory infiltrates, predominantly T cells, which were endomysial (49%), perimysial (42%) and perivascular (41%). Few studies (18%, n = 8/44) evaluated the presence of B-cells. Myofiber atrophy was present in 48% (n = 104/218) of biopsies, and was predominantly perifascicular in 19% (n = 6/31), with necrosis reported in 56% (n = 162/290) of cases. Sarcolemmal MHC-I upregulation was found in 72% (n = 64/89) of biopsies. Non-specified C5b-9 deposition was described in 39% of muscle biopsies (n = 28/72). Neurogenic features were present in 23% (n = 44/191); endomysial fibrosis was reported in 35% (n = 120/340); and rimmed vacuoles were observed in 32% (n = 11/34) of biopsies. Capillaropathy, such as capillary dropout and/or ultrastructural endothelial abnormalities, was reported in 33% (n = 43/129) of cases. Reported ENMC categories were mainly polymyositis (21%), non-specific myositis (19%), immune-mediated necrotizing myopathy (16%), and dermatomyositis (8%). Histopathological features were analyzed according to serological subtypes in 28 studies, including anti-PM-Scl (n = 48), -Ku (n = 23) and -U1RNP (n = 90). Most of these biopsies demonstrated inflammatory infiltrates (range 49-85%) as well as MHC-I expression (range 63-81%). Necrosis was associated with anti-Ku (85%) and anti-U1RNP (73%), while anti-Ku was also associated with neurogenic features and rimmed vacuoles in 57% and 25% of cases, respectively.

CONCLUSION

Our review suggests that SM is characterized by heterogeneous pathological features using definitions included in current histopathological criteria. Whether a distinct histopathological signature exists in SM remains to be determined. SSc-specific and SSc-associated autoantibodies may help define more homogeneous histopathological subsets.

Comparison of the 2017 EULAR/ACR Criteria with Clinicoserologic Criteria for the Classification of Idiopathic Inflammatory Myopathies in Korean Patients

PURPOSE

To investigate correlations between myositis-specific autoantibodies (MSA) or myositis-associated antibodies (MAA) and clinical features, thereby demonstrating the utility of clinicoserologic classification in idiopathic inflammatory myopathies (IIM) patients.

MATERIALS AND METHODS

We conducted a multicenter study of 108 adult patients (age ≥18 years) who were diagnosed with IIM by Peter and Bohan criteria or 2004 European Neuromuscular Centre (ENMC) criteria. Clinical data were obtained by medical record review. Immunoblot assay with Euroline strip (EUROIMMUN, Germany) was performed using the sera of dermatomyositis (DM, n=56), polymyositis (PM, n=45), amyopathic DM (n=5), DM sine dermatitis (n=1), and immune mediated necrotizing myopathy (n=1) patients. Patients were classified based on two classifications: 2017 EULAR/ACR and novel clinicoserologic classification.

RESULTS

According to 2017 EULAR/ACR criteria, DM and PM were the most and the second most frequent entities. Overlap myositis was the major entity of IIM, and the frequency of PM was significantly lower when applying clinicoserologic classification criteria. Sixty-nine (63.9%) patients had one or more MSA, and 61 (56.5%) patients had one or more MAA. Interstitial lung disease was closely associated with anti-MDA5 and anti-ARS, and DM-specific skin lesions were frequently observed in patients with anti-TIF1γ, anti-SRP, and anti-MDA5.

CONCLUSION

The clinicoserologic criteria based on MSA/MAA positivity could reflect more precise clinical features of IIM. Establishment of a laboratory system routinely available to screen for MSA/MAA status will be beneficial to provide precise diagnosis and proper management of IIM patients.