Clinical significance of myositis-specific autoantibodies

Effectiveness and safety of plasma exchange for anti-MDA5 antibody-positive clinically amyopathic dermatomyositis with rapidly progressive interstitial lung disease refractory to intensive immune suppression therapy: A case series

INTRODUCTION

Clinically amyopathic dermatomyositis (CADM) with anti-melanoma differentiation-associated gene 5 (MDA5) antibody (Ab) with rapidly progressive interstitial lung disease (RP-ILD) is often refractory for intensive immunosuppression. In this study, we verified the effectiveness and safety of plasma exchange (PEx) for this lethal disease.

METHODS

We retrospectively examined the clinical course and adverse effect (AE) of 12 patients with anti-MDA5 Ab-positive CADM between January 2017 and December 2021 in our hospital.

RESULTS

Five out of six patients treated with simple PEx using fresh frozen plasma or 5% albumin survived with or without home oxygen therapy. Multiple PEx (15-20 times) were required to achieve satisfactory improvement as well as remission of CADM. The AEs caused by PEx were resolved using conventional methods.

CONCLUSION

PEx might be a promising option for controlling the disease activity of anti-MDA5 Ab-positive CADM with severe RP-ILD and may contribute to better survival.

Current Biomarker Strategies in Autoimmune Neuromuscular Diseases

Inflammatory neuromuscular disorders encompass a diverse group of immune-mediated diseases with varying clinical manifestations and treatment responses. The identification of specific biomarkers has the potential to provide valuable insights into disease pathogenesis, aid in accurate diagnosis, predict disease course, and monitor treatment efficacy. However, the rarity and heterogeneity of these disorders pose significant challenges in the identification and implementation of reliable biomarkers. Here, we aim to provide a comprehensive review of biomarkers currently established in Guillain-Barré syndrome (GBS), chronic inflammatory demyelinating polyneuropathy (CIDP), myasthenia gravis (MG), and idiopathic inflammatory myopathy (IIM). It highlights the existing biomarkers in these disorders, including diagnostic, prognostic, predictive and monitoring biomarkers, while emphasizing the unmet need for additional specific biomarkers. The limitations and challenges associated with the current biomarkers are discussed, and the potential implications for disease management and personalized treatment strategies are explored. Collectively, biomarkers have the potential to improve the management of inflammatory neuromuscular disorders. However, novel strategies and further research are needed to establish clinically meaningful biomarkers.

Concomitant Use of Steroids and Immunotherapy in a Patient With Paraneoplastic Dermatomyositis and Gastroesophageal Adenocarcinoma

Idiopathic inflammatory myopathies (IIMs) are a heterogeneous group of autoimmune pathologies often associated with occult malignancies. Glucocorticoids (GCs) represent the initial therapy to control symptoms and avoid complications. Immune checkpoint inhibitors (ICIs) have shifted the paradigm of cancer treatment. Nivolumab has become the first-line therapy in combination with chemotherapy for untreated, unresectable, non-HER-2-positive advanced gastroesophageal adenocarcinoma. The use of ICIs increases the risk of immune-related adverse events (irAEs), especially in patients with autoimmune diseases, and patients receiving steroids or immunosuppressants might be associated with poorer immunotherapy efficacy. We describe the case of a 49-year-old male who was diagnosed with paraneoplastic dermatomyositis (PDM) and gastroesophageal adenocarcinoma. He was started on prednisone taper, and concomitantly, he was started on chemotherapy with fluorouracil, leucovorin, oxaliplatin, and docetaxel (FLOT), with administration of pegfilgrastim and dexamethasone during each cycle. Additionally, he was started on nivolumab. His course was complicated by worsening episodes of myopathies due to the immunotherapy, requiring adjustments to the prednisone taper. A positron emission tomography (PET) scan and repeat endoscopic ultrasonography with biopsy eight months after therapy initiation showed no major evidence of disease compared to prior. In our case, we exemplified the importance of multidisciplinary management for dosing and tapering of GCs and timing of ICI initiation, and we described the successful response to nivolumab in a patient with autoimmune disease concurrently receiving GCs.

The prognostic role of C-reactive protein to albumin ratio and anti-MDA5 antibody-positive in idiopathic inflammatory myopathy: a retrospective study

This cohort study aimed to identify the characteristics and risk factors of adult idiopathic inflammatory myopathy-associated interstitial lung disease (IIM-ILD) and further explore the prognostic factors of IIM-ILD. We extracted data regarding 539 patients with laboratory-confirmed idiopathic inflammatory myopathy (IIM) with or without interstitial lung disease (ILD) from the Second Xiangya Hospital of Central South University between January 2016 and December 2021. The regression analysis was conducted to identify the possible risk factors for ILD as well as mortality. Of 539 IIM patients, 343 (64.6%) were diagnosed with IIM-ILD. The median (IQR) baseline neutrophil-to-lymphocyte ratio (NLR), C-reactive protein to albumin ratio (CAR) and ferritin were 4.1371 (2.6994-6.8143), 0.1685 (0.0641-0.5456) and 393.6 (210.6-532.2), respectively. Risk factors associated with IIM-ILD were older age (p = 0.002), arthralgia (p = 0.014), lung infection (p = 0.027), hemoglobin (p = 0.022), high CAR (p = 0.014), anti-aminoacyl-tRNA synthetase (anti-ARS) antibody-positive (p < 0.001), and anti-MDA5 antibody-positive (p < 0.001). The IIM-ILD patients whose age at diagnosis of disease ≥ 59.5 (HR = 2.673, 95% CI 1.588-4.499, p < 0.001), NLR ≥ 6.6109 (HR = 2.004, 95% CI 1.193-3.368, p = 0.009), CAR ≥ 0.2506 (HR = 1.864, 95% CI 1.041-3.339, p = 0.036), ferritin ≥ 397.68 (HR = 2.451, 95% CI 1.245-4.827, p = 0.009) and anti-MDA5 antibody-positive (HR = 1.928, 95% CI 1.123-3.309, p = 0.017) had a higher mortality rate. High CAR and anti-MDA5 antibody-positive are more likely to be associated with a high mortality rate of IIM-ILD, which can be used as serum biomarkers, especially the CAR, a simple, objective tool to assess the prognosis of IIM.

Overlap Syndrome in a Male Presenting With Progressive Lower Limb Weakness: A Case Report

Overlap syndrome refers to a large group of inflammatory rheumatic conditions characterized by the co-existence of clinical manifestations that include different organ systems and meet the criteria of more than one rheumatic disease. Overlap syndromes are less common compared with the conditions they encompass, for example, the global prevalence of systemic lupus erythematosus (SLE) is estimated to be 43.7 per 100,000 persons, of which only around 3.4-6.3% present with SLE-myositis overlap. Although rare, overlap syndromes commonly include lupus, rheumatoid arthritis, scleroderma, and myositis. Because overlap syndrome can manifest in several ways and has an unpredictable course, it poses a challenge to multidisciplinary teams that examine and treat patients. Therefore, we must not disregard any signs and symptoms as they might have a huge impact on the progression of the disease and the overall outcome of the treatment. We present a rare case of SLE-myositis overlap syndrome in a 44-year-old male. He initially presented with gradual weakness in the proximal muscles of the bilateral lower limb. This patient was diagnosed as having SLE with positive 5g protein/24 hours, anti-nuclear, low C3, anti-U1RNP, anti-Ro, and anti-La antibodies, as well as membranous lupus nephritis evident by the results of renal biopsy. The diagnosis of myositis was also made according to the history and evaluation of the patient, the high titer of muscle enzymes creatine kinase level, and MRI result. Although the patient tested positive for anti-U1RNP, he did not meet the criteria of mixed connective tissue disease. Eventually, the patient was found to have overlap syndrome. The prevalence of overlap between SLE and myositis is relatively rare and varies from 3.4% to 6.3%. To our knowledge, no study has discussed or reported its prevalence among males.

Overlap syndrome involving anti-OJ antibody-positive polymyositis, systemic lupus erythematosus and Sjögren's syndrome: A case report and literature review

Anti-OJ antibody is relatively rarely detected in patients with anti-synthetase syndrome, which is polymyositis (PM)/dermatomyositis (DM) with anti-aminoacyl transfer RNA synthetase antibodies. There have been few case reports of anti-OJ antibody-positive PM/DM complicated by other connective tissue disorders. Herein, we report the case of a 33-year-old woman, who was admitted to our hospital with fever, muscle weakness, and dyspnea on exertion. She was diagnosed with anti-OJ antibody-positive PM, overlapping systemic lupus erythematosus (SLE), and Sjögren's syndrome (SS). Her symptoms and clinical findings improved after treatment with prednisolone 1 mg/kg/day without immunosuppressive agents. This is the first case of overlap syndrome with anti-OJ antibody-positive PM, SLE, and SS.

Prevalence and clinical associations of myositis antibodies in a large cohort of interstitial lung diseases

Background

Serologic testing for autoantibodies is recommended in interstitial lung diseases (ILDs), as connective tissue diseases (CTDs) are an important secondary cause. Myositis antibodies are associated with CTD-ILD, but clinical associations with other ILDs are unclear. In this study, associations of myositis antibodies in various ILDs were evaluated.

Methods

1463 ILD patients and 116 healthy subjects were screened for myositis antibodies with a line-blot assay on serum available at time of diagnosis. Additionally, bronchoalveolar lavage fluid (BALf) was analysed.

Results

A total of 394 patients demonstrated reactivity to at least one antibody, including anti-Ro52 (36.0%), anti-Mi-2β (17.3%) and anti-Jo-1 (10.9%). Anti-Jo-1 (OR 6.4; p<0.100) and anti-Ro52 (OR 6.0; p<0.001) were associated with CTD-ILD. Interestingly, anti-Mi-2β was associated with idiopathic pulmonary fibrosis (IPF; OR 5.3; p = 0.001) and hypersensitivity pneumonitis (HP; OR 5.9; p<0.001). Furthermore, anti-Mi-2β was strongly associated with a histological usual interstitial pneumonia (UIP) pattern (OR 6.5; p < 0.001). Moreover, anti-Mi-2β reactivity was identified in BALf and correlated with serum anti-Mi-2β (r = 0.64; p = 0.002). No differences were found in survival rates between ILD patients with and without serum Mi-2β reactivity (hazard ratio 0.835; 95% CI 0.442–1.575; p = 0.577).

Conclusion

In conclusion, novel associations of antibody Mi-2β with fibrotic ILD were found. Furthermore, serum anti-Mi-2β was associated with a histological UIP pattern and presence of anti-Mi-2β in BALf. Possibly, anti-Mi-2β could be implemented as a future diagnostic biomarker for fibrotic ILD.

Signal Recognition Particle in Human Diseases

The signal recognition particle (SRP) is a ribonucleoprotein complex with dual functions. It co-translationally targets proteins with a signal sequence to the endoplasmic reticulum (ER) and protects their mRNA from degradation. If SRP is depleted or cannot recognize the signal sequence, then the Regulation of Aberrant Protein Production (RAPP) is activated, which results in the loss of secretory protein mRNA. If SRP recognizes the substrates but is unable to target them to ER, they may mislocalize or degrade. All these events lead to dramatic consequence for protein biogenesis, activating protein quality control pathways, and creating pressure on cell physiology, and might lead to the pathogenesis of disease. Indeed, SRP dysfunction is involved in many different human diseases, including: congenital neutropenia; idiopathic inflammatory myopathy; viral, protozoal, and prion infections; and cancer. In this work, we analyze diseases caused by SRP failure and discuss their possible molecular mechanisms.

Clinical Features of Anti-Synthetase Syndrome Associated with Prognosis in Patients with Dermatomyositis and Polymyositis

We evaluated whether the clinical features of anti-synthetase syndrome (ASA)—myositis, fever, arthritis, mechanic’s hand, Raynaud’s phenomenon and interstitial lung disease—are relevant to prognosis in patients with dermatomyositis/polymyositis (DM/PM). A retrospective analysis was performed to identify patients diagnosed with DM/PM according to Bohan and Peter criteria. Clinical information, laboratory data and the presence of ASA clinical features at disease diagnosis were searched, and the outcomes of all-cause mortality, intensive care unit admission and disease remission at 1 year were assessed. Among the 86 patients included, fever (36.0%) and interstitial lung disease (26.7%) were the most common ASA clinical features. During the follow-up, 12 patients experienced death, and 7 of the 12 deaths (58.3%) occurred within 3 months of DM/PM diagnosis. Mortality was more frequently observed in those presenting with fever than in those without (25.8% versus 7.3%, p = 0.024). Multivariable Cox proportional analysis revealed that male sex (hazard ratio [HR] 5.53, 95% confidence interval [CI] 1.65, 18.49, p < 0.01) and fever (HR 4.20, 95% CI 1.26, 14.01, p = 0.02) independently predicted mortality. The clinical impact of fever was consistent in both sexes. Fever could be a warning signal heralding the poor outcome of mortality in patients with DM/PM, especially in early disease phases.

Myositis Antibodies and Interstitial Lung Disease

BACKGROUND

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

CONTENT

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

SUMMARY

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

Dermatomyositis Which Was Double Positive for Anti-MDA5 and Anti-ARS Antibodies That Was Successfully Treated by Intensive Immunosuppressive Therapy

Myositis-specific autoantibody is associated with the clinical phenotype and prognosis of dermatomyositis. Anti-melanoma differentiation-associated gene 5 (MDA5) and anti-aminoacyl-tRNA synthetase (ARS) antibodies are generally mutually exclusive. We herein present an extremely rare case of dermatomyositis which showed double positivity for anti-MDA5 and anti-ARS antibodies. There have been very few reported cases of double positive anti-MDA5, anti-ARS antibodies. In such cases, the clinical characteristics of each autoantibody can coexist. Thus, we should pay attention to the rapidly progressing features of anti-MDA5 as well as the chronic relapsing features of anti-ARS for the better management of this rare condition.

The Significance of Autoantibodies in Juvenile Dermatomyositis

Juvenile dermatomyositis is a chronic and rare autoimmune disorder classified into the spectrum of idiopathic inflammatory myopathies. Although this entity is mainly characterized by the presence of pathognomonic cutaneous lesions and proximal muscle weakness, the clinical manifestation can be highly heterogeneous; thus, diagnosis might be challenging. Current treatment recommendations for juvenile dermatomyositis, based mainly upon case series, include the use of corticosteroids, immunomodulatory, and immunosuppressive agents. Recently, several specific autoantibodies have been shown to be associated with distinct clinical phenotypes of classic dermatomyositis. There is a need to further evaluate their relevance in the formation of various clinical features. Furthermore, while providing more personalized treatment strategies, one should consider diversity of autoantibody-related subgroups of juvenile dermatomyositis.

[Anti-nuclear matrix protein 2 antibody-positive dermatomyositis with the preferential involvement of neck extensors: a case report]

A 68-year-old man with a 2-month history of progressive weakness and spontaneous pain in proximal limb muscles presented to our hospital with a dropped head. He started experiencing progressive dysphagia several days before admission. On admission, he had muscle weakness of the limbs and neck extensors with edema and induration in distal extremities. Laboratory tests showed elevation of muscle enzymes. FDG-PET/CT demonstrated multiple hypermetabolic lymph nodes, but the primary site was not identified; thus, metastatic carcinoma of unknown primary origin was considered. The patient was diagnosed with anti-nuclear matrix protein 2 antibody-positive paraneoplastic myopathy based on serum tests. Histological findings of the left biceps brachii muscle biopsy revealed severe variation in fiber size and perifascicular myofiber atrophy. Myofibers exhibited myxovirus resistance protein A expression predominantly in the perifascicular region. Following intravenous methylprednisolone pulse therapy and intravenous immunoglobulin, the patient's muscle strength improved with normalization of muscle enzyme levels. The dropped head was considered to have resulted from the preferential involvement of neck extensors based on the observed FDG-PET/CT uptake in neck extensors.

Charakteristika von Dermatomyositis-Patienten mit und ohne Malignom-Assoziation

HINTERGRUND

Die Dermatomyositis gehört zur Gruppe der seltenen, idiopathischen, inflammatorischen Myositiden. Für die paraneoplastische Form der Dermatomyositis wurde in der Vergangenheit ein Zusammenhang mit Malignomen erkannt. Faktoren, die für eine Malignom-Assoziation sprechen, werden bis heute untersucht.

PATIENTEN UND METHODIK

Es wurden retrospektiv über einen Zeitraum von 15 Jahren die Daten von 63 Patienten mit Dermatomyositis analysiert.

ERGEBNISSE

Folgende Faktoren gaben einen Hinweis für eine Dermatomyositis mit Malignom-Assoziation: ein höheres Patientenalter (> 52 Jahre [P = 0,001], > 65 Jahre [P = 0,002], ≥ 75 Jahre [P = 0,002]), eine kürzere Zeit zwischen Erstmanifestation und Erstdiagnose (Malignom-Gruppe: 59 Tage vs. Nicht-Malignom-Gruppe: 137 Tage [P = 0,022]), eine Hautbeteiligung in Form von Gottron-Zeichen (P = 0,045), zentrofazialen Erythemen (P = 0,036) oder typischen Erythemen an den Ober-/Unterarmen (P = 0,019), eine oropharyngeale Beteiligung (P = 0,015) und eine GPT-Erhöhung (P = 0,031). Folgende Faktoren sprachen eher gegen eine Malignom-Assoziation: ein jüngeres Patientenalter (≤ 52 Jahre [P = 0,001], 40-65 Jahre [P = 0,045]) und Juckreiz (P = 0,026).

SCHLUSSFOLGERUNGEN

In der Literatur finden sich heterogene Ergebnisse zu den genannten Faktoren hinsichtlich ihrer Eignung als Marker für eine Malignom-Assoziation. Erschwert ist die Faktorenfindung aufgrund kleiner Studienpopulationen, wenigen prospektiven und kontrollierten Studien, die Einordnung von Populationen als Myositis-Patienten ohne Differenzierung und eine inkonsistente Verwendung der Nomenklatur. Mit unserer Studie wollen wir einen wichtigen Beitrag zur Identifizierung von Risikofaktoren bei Dermatomyositis mit Malignom-Assoziation leisten.

Paraneoplastic dermatomyositis and prostate cancer: Myopathy regression under cancer-directed therapy

Prostate cancer is the second most frequent malignancy in men worldwide and the fifth leading cause of death. Dermatomyositis (DM) is a rare idiopathic inflammatory myopathy characterized by musculocutaneous manifestations. However, DM can also present as a paraneoplastic syndrome of an underlying neoplasm. We report a case of a 65-year-old man diagnosed with prostate adenocarcinoma in the setting of severe dysphagia, muscle weakness and a facial erythematous rash. At first, the DM-related symptoms resolved with the initial treatment for the underlying malignancy. Yet, they flared up as the tumor progressed. To sum up, DM is a rare systemic disorder with unknown etiology. There is a well-established association between DM and malignancy. Malignancy-headed therapy can improve DM manifestations and the recurrence of DM symptoms may act as an early warning of malignancy relapse.

Characteristics of dermatomyositis patients with and without associated malignancy

BACKGROUND

Dermatomyositis belongs to the rare idiopathic, inflammatory myositis group. A previously postulated link between some cases of dermatomyositis and malignancy has been established in recent years. Criteria suggestive of a malignancy association are still being explored.

PATIENTS AND METHODS

We retrospectively analyzed data from 63 patients with dermatomyositis over a period of 15 years.

RESULTS

The following criteria argue for cancer-associated dermatomyositis: older age (> 52 years [P = 0.001], > 65 years [P = 0.002], ≥ 75 years [P = 0.002]), shorter time between manifestation and diagnosis of dermatomyositis (malignancy group: 59 days vs. non-malignancy group: 137 days [P = 0.022]), typical skin involvement such as Gottron sign (P = 0.045), centrofacial erythema (P = 0.036) and typical erythema on the upper arms and forearms (P = 0.019), oropharyngeal involvement (P = 0.015) and increased ALT (P = 0.031). The following criteria argue for non-cancer-associated dermatomyositis: younger age (≤ 52 years [P = 0.001], 40-65 years [P = 0.045]) and pruritus (P = 0.026).

CONCLUSIONS

The aforementioned criteria have been documented in the literature, but reported findings are heterogenous concerning the suitability of their markers for malignancy association. Small study populations, few prospective controlled studies, summarization of different forms of myositis and inconsistent use nomenclature contribute to biased results. Our study aims to make an important contribution toward the identification of risk factors in cancer-associated dermatomyositis.

Assessment of antinuclear antibodies (ANA): National recommendations on behalf of the Croatian society of medical biochemistry and laboratory medicine

Antinuclear antibodies (ANA) represent a family of autoantibodies targeting ubiquitous cellular constituents and are a hallmark of systemic inflammatory autoimmune rheumatic diseases named connective tissue diseases (CTD). The gold standard method for ANA determination is indirect immunofluorescence (IIF) on the human laryngeal epidermoid carcinoma cell line type 2 substrate (HEp-2), but with increasing demand for ANA testing, novel methods eased for automation emerged, which allows testing by staff less experienced in this specific field of laboratory diagnostic. In 2016 The working group (WG) for laboratory diagnostics of autoimmune diseases as part of the Committee for the Scientific Professional Development of the Croatian Society of Medical Biochemistry and Laboratory Medicine (CSMBLM) published the data of a survey regarding general practice in laboratory diagnostics of autoimmune diseases in Croatia. Results indicated high diversity in the performance of autoantibody testing as well as reporting of the results and indicated the need of creating recommendations for the assessment of ANA that would help harmonize diagnostics of systemic autoimmune rheumatic diseases in Croatia. This document encompasses twenty-seven recommendations for ANA testing created concerning indications for ANA testing, preanalytical, analytical, and postanalytical issues, including rational algorithm and quality control assurance. These recommendations are based on the relevant international recommendations and guidelines for the assessment of ANA testing and relevant literature search and should help to harmonize the approach in ANA testing and clarify differences in interpretation of the results obtained using different methods of determination.

Reappraisal of the incidence, various types and risk factors of malignancies in patients with dermatomyositis and polymyositis in Taiwan

Our study aimed to investigate the incidence, risk factors and time to occurrence of malignancy in patients with dermatomyositis (DM) and polymyositis (PM). The electronic medical records of 1100 patients with DM and 1164 patients with PM were studied between January 2001 and May 2019. Malignancies after myositis were diagnosed in 61 (5.55%) patients with DM and 38 (3.26%) patients with PM. The cumulative incidence of malignancies in patients with DM were significantly higher than patients with PM (hazard ratio = 1.78, log-rank p = 0.004). Patients with DM had a greater risk of developing malignancy than those with PM at 40–59 years old (p = 0.01). Most malignancies occurred within 1 year after the initial diagnosis of DM (n = 35; 57.38%). Nasopharyngeal cancer (NPC) was the most common type of malignancy in patients with DM (22.95%), followed by lung, and breast cancers. In patients with PM, colorectal, lung and hepatic malignancies were the top three types of malignancy. The risk factors for malignancy included old age (≥ 45 years old) and low serum levels of creatine phosphokinase (CPK) for patients with DM and male sex and low serum levels of CPK for patients with PM. Low serum levels of CPK in patients with myositis with malignancy represented a low degree of muscle destruction/inflammation, which might be attributed to activation of the PD-L1 pathway by tumor cells, thus inducing T-cell dysfunction mediating immune responses in myofibers. A treatment and follow-up algorithm should explore the occurrence of malignancy in different tissues and organs and suggested annual follow-ups for at least 5.5 years to cover the 80% cumulative incidence of malignancy in patients with DM and PM.

Clinical impact of myositis-specific autoantibodies on long-term prognosis of juvenile idiopathic inflammatory myopathies: multicenter study

OBJECTIVES

This study aimed to investigate the clinical characteristics, treatment, and prognosis of juvenile idiopathic inflammatory myopathies (JIIM) in Japan for each myositis-specific autoantibody (MSA) profile.

METHODS

A multicenter, retrospective study was conducted using data of patients with JIIM at nine pediatric rheumatology centers in Japan. Patients with MSA profiles, determined by immunoprecipitation using stored serum from the active stage, were included.

RESULTS

MSA were detected in 85 of 96 cases eligible for the analyses. Over 90% of the patients in this study had one of the following three MSA types: anti-MDA5 (n = 31), anti-TIF1γ (n = 25), and anti-NXP2 (n = 25) antibodies. Gottron papules and periungual capillary abnormalities were the most common signs of every MSA group in the initial phase. The presence of interstitial lung disease (ILD) was the highest risk factor for patients with anti-MDA5 antibodies. Most patients were administered multiple drug therapies: glucocorticoids and methotrexate were administered to patients with anti-TIF1γ or anti-NXP2 antibodies. Half of the patients with anti-MDA5 antibodies received more than three medications including intravenous cyclophosphamide, especially patients with ILD. Patients with anti-MDA5 antibodies were more likely to achieve drug-free remission (29% vs 21%) and less likely to relapse (26% vs 44%) than others.

CONCLUSION

Anti-MDA5 antibodies are the most common MSA type in Japan, and patients with this antibody are characterized by ILD at onset, multiple medications including intravenous cyclophosphamide, drug-free remission, and a lower frequency of relapse. New therapeutic strategies are required for other MSA types.

Prevalence of Novel Myositis Autoantibodies in a Large Cohort of Patients with Interstitial Lung Disease

Connective tissue diseases (CTDs) are an important secondary cause of interstitial lung disease (ILD). If a CTD is suspected, clinicians are recommended to perform autoantibody testing, including for myositis autoantibodies. In this study, the prevalence and clinical associations of novel myositis autoantibodies in ILD are presented. A total of 1194 patients with ILD and 116 healthy subjects were tested for antibodies specific for Ks, Ha, Zoα, and cN1A with a line-blot assay on serum available at the time of diagnosis. Autoantibodies were demonstrated in 63 (5.3%) patients and one (0.9%) healthy control (p = 0.035). Autoantibodies were found more frequently in females (p = 0.042) and patients without a histological and/or radiological usual interstitial pneumonia (UIP; p = 0.010) and a trend towards CTD-ILDs (8.4%) was seen compared with other ILDs (4.9%; p = 0.090). The prevalence of antibodies specific for Ks, Ha, Zoα, and cN1A was, respectively, 1.3%, 2.0%, 1.4%, and 0.9% in ILD. Anti-Ha and Anti-Ks were observed in males with unclassifiable idiopathic interstitial pneumonia (unclassifiable IIP), hypersensitivity pneumonitis (HP), and various CTD-ILDs, whereas anti-cN1A was seen in females with antisynthetase syndrome (ASS), HP, and idiopathic pulmonary fibrosis (IPF). Anti-Zoα was associated with CTD-ILD (OR 2.5; 95%CI 1.11-5.61; p = 0.027). In conclusion, a relatively high prevalence of previously unknown myositis autoantibodies was found in a large cohort of various ILDs. Our results contribute to the awareness that circulating autoantibodies can be found in ILDs with or without established CTD. Whether these antibodies have to be added to the standard set of autoantibodies analysed in conventional myositis blot assays for diagnostic purposes in clinical ILD care requires further study.

Myositis-specific autoantibodies in adults with idiopathic inflammatory myopathy: correlations with diagnosis and disease activity

OBJECTIVE

To determine the relationship of myositis autoantibodies with the diagnosis and severity of idiopathic inflammatory myopathy (IIM) using the 2017 EULAR/ACR idiopathic inflammatory myopathy classification criteria and the myositis disease activity assessment tool (MDAAT).

METHODS

Patients who met the new diagnostic criteria were tested for serum myositis-specific autoantibodies (MSAs) and myositis-associated autoantibodies (MAAs), and then classified into different subgroups based on autoantibody positivity. Patients were also diagnosed with possible IIM, probable IIM, and definite IIM. The MDAAT was used to evaluate muscular and extramuscular disease activity. The relationships of diagnostic classification with positivity for different myositis autoantibodies were determined.

RESULTS

There were 118 patients, and 81% of them had one or more myositis autoantibody. Anti-Jo-1 was the most common MSA, and anti-Ro-52 was the most common MAA. Sixteen patients (14%) had possible IIM, 36 (31%) had probable IIM, and 66 (56%) had definite IIM. MSA-positive patients were significantly more common in the definite IIM group, but MAA positivity was unrelated to diagnostic classification. Positivity for MSAs or MAAs had no correlations with muscle disease activity. Extramuscular disease activity was greater in MSA-positive than MSA-negative patients, but MAA positivity had no significant association with extramuscular disease activity.

CONCLUSIONS

MSA positivity aids in the diagnosis of IIM. MSA positivity was associated with greater extramuscular disease activity. Improving the clinical application of MSAs may enhance the individualized treatment of patients with IMM. Key Points • In this paper, we explore the relationships between the myositis autoantibodies and the diagnosis and the disease activity of inflammatory myopathy. • Positive myositis-specific autoantibodies is associated with the establishment of diagnosis and higher extramuscular disease activity. • Thus, more extensive application of myositis autoantibodies maybe the key for further disease assessment and research.

Calcinosis Biomarkers in Adult and Juvenile Dermatomyositis

Dermatomyositis (DM) is a rare idiopathic inflammatory myopathy characterized by muscle weakness and cutaneous manifestations in adults and children. Calcinosis, a complication of DM, is the abnormal deposition of insoluble calcium salts in tissues, including skin, subcutaneous tissue, tendons, fascia, and muscle. Calcinosis is more commonly seen in juvenile DM (JDM), but also develops in adult DM. Although the mechanism of calcinosis remains unclear, several pathogenic hypotheses have been proposed, including intracellular accumulation of calcium secondary to an alteration of the cellular membrane by trauma and inflammation, local vascular ischemia, dysregulation of mechanisms controlling the deposition and solubility of calcium and phosphate, and mitochondrial damage of muscle cells. Identifying calcinosis biomarkers is important for early disease detection and risk assessment, and may lead to novel therapeutic targets for the prevention and treatment of DM-associated calcinosis. In this review, we summarize myositis autoantibodies associated with calcinosis in DM, histopathology and chemical composition of calcinosis, genetic and inflammatory markers that have been studied in adult DM and JDM-associated calcinosis, as well as potential novel biomarkers.

Patients with Interstitial Lung Disease Secondary to Autoimmune Diseases: How to Recognize Them?

The diagnostic assessment of patients with Interstitial Lung Disease (ILD) can be challenging due to the large number of possible causes. Moreover, the diagnostic approach can be limited by the severity of the disease, which may not allow invasive exams. To overcome this issue, the referral centers for ILD organized Multidisciplinary Teams (MDTs), including physicians and experts in complementary discipline, to discuss the management of doubtful cases of ILD. MDT is currently considered the gold standard for ILD diagnosis, but it is not often simple to organize and, furthermore, rheumatologists are still not always included. In fact, even if rheumatologic conditions represent a common cause of ILD, they are sometimes difficult to recognize, considering the variegated clinical features and their association with all possible radiographic patterns of ILD. The first objective of this review is to describe the clinical, laboratory, and instrumental tests that can drive a diagnosis toward a possible rheumatic disease. The secondary objective is to propose a set of first-line tests to perform in all patients in order to recognize any possible rheumatic conditions underlying ILD.

Interleukin-33/suppression of tumorigenicity 2 (IL-33/ST2) axis in idiopathic inflammatory myopathies and its association with laboratory and clinical parameters: a pilot study

Idiopathic inflammatory myopathies (IIM) are rare connective tissue diseases, which can lead to internal organ involvement. IL-33/ST2 pathway is involved in the pathogenesis of numerous diseases including autoimmune disorders. IL-33 fulfils cardioprotective function, while soluble ST2 (sST2) is a decoy receptor that reduces protective impact of IL-33. The aim of the study was to evaluate the concentrations of sST2 and IL-33 in sera of patients with IIM and evaluate its associations with the clinical course of the disease. Patients with IIM as well as age- and sex-matched healthy controls were recruited. Concentrations of sST2 and IL-33 were assessed with ELISA in sera of both patients and controls. Patients were asked to fill in the questionnaires concerning clinical symptoms and physical functioning. Concentrations of sST2 and IL-33 were correlated with the results of laboratory tests and clinical symptoms. Concentrations of sST2 were significantly higher in IIM group than in healthy subjects (median sST2 in IIM 26.51 vs in healthy controls 21.39; p = 0.03). In the majority of patients, IL-33 concentrations did not exceed the detection limit. Anti-SRP-positive patients presented significantly higher concentrations of sST2 as compared to anti-SRP-negative patients (p = 0.04). In patients with anti-Ro52 antibodies, sST2 concentrations were significantly lower than in anti-Ro52-negative patients (p = 0.02). Concentrations of sST2 correlated with the degree of disability evaluated with Health Assessment Questionnaire. sST2 is increased in patients with IIM and its concentration correlates with the degree of disability. In patients with anti-SRP antibodies, levels of sST2 are exceptionally high.

[Severe MDA5 dermatomyositis associated with cancer and controlled by JAK inhibitor]

Dermatomyositis is an idiopathic inflammatory myopathy with various clinical and serological profiles, including poor prognosis forms for which aggressive immunosuppressive treatment is warranted. We report the case of a 60-year-old woman referred to our hospital for an anti-melanoma differentiation-associated 5 gene antibody-positive dermatomyositis (MDA5 DM) with rapidly progressive interstitial pneumonia, typical cutaneous features and muscular impairment. Treatment with high-dose methylprednisolone, cyclophosphamide and gamma globulin was performed, but the patient remained corticodependant. Blood detection of positive interferon signature justified the administration of an anti-JAK1/2, leading to the clinical remission and the regression of the interferon signature. After 12 months of follow up, a small cell carcinoma was discovered, raising the question of a paraneoplastic syndrome, for which the most recent datas are quite reassuring for this kind of MDA5 DM. The presentation of this case is of twofold interest: describing one of the first report of successful treatment of intereronopathy MDA5 DM with ruxolitinib and highlighting an association with a cancer, which is not expected for this phenotype of dermatomyositis.