Interstitial lung disease associated with the idiopathic inflammatory myopathies: what progress has been made in the past 35 years?

A Case of Antisynthetase Syndrome in the Setting of SARS-Cov-2 Infection

Antisynthetase syndrome is a complex autoimmune disorder, and one of the key criteria for diagnosis is the presence of myositis. Additionally, evidence of interstitial lung disease (ILD) is another important indicator for diagnosis; other clinical features associated with antisynthetase syndrome include arthritis, unexplained and persistent fever, Raynaud's phenomenon, and the presence of mechanic's hands. We report a case of a 36-year-old male who presented to the emergency department with shortness of breath and proximal muscle weakness in the setting of severe acute respiratory syndrome coronavirus 2 (SARS-Cov-2) infection, as his inflammatory markers were elevated and he exhibited features suspicious for antisynthetase syndrome, he was started on methylprednisolone 40 mg intravenously every eight hours, and a myositis panel was checked. In addition, a chest computed tomography (CT) exhibited ground-glass opacities which were compatible with coronavirus disease 2019 (COVID-19). A magnetic resonance image (MRI) of both thighs was done, revealing significant swelling and confirming the suspicion of myositis as his muscle strength in his lower extremities took significant time to improve. As days passed, his muscle strength improved significantly and his creatine phosphatase kinase (CPK) values trended down, indicating that his myositis was improving as well. He was transitioned to oral prednisone 60 mg daily and was discharged home with a rheumatology follow-up to define long-term treatment. A myositis panel revealed anti-glycyl-transferRNA synthetase (EJ) autoantibody positivity and a diagnosis was established. Our case revealed how sometimes laboratory values do not necessarily correlate with disease severity and how we have to do a thorough history of present illness and physical exam to think about unusual diagnoses before putting laboratory data into context.

Antisynthetase Syndrome With Paraneoplastic Antibodies

Antisynthetase syndrome (ASyS) is an uncommon systemic autoimmune disorder characterized by the presence of autoantibodies targeting aminoacyl-transfer RNA (tRNA) synthetase. The syndrome displays a diverse range of clinical manifestations affecting multiple organs, thereby posing a diagnostic challenge. In this report, we present an unusual case of a patient diagnosed with ASyS, displaying positive anti-PL-12 antibodies along with paraneoplastic antibodies. To the best of our knowledge, this is the first documented case in the existing literature describing ASyS with the presence of anti-PL-12 antibodies and concomitant paraneoplastic antibodies in the context of ductal carcinoma in situ.

Predictive factors for progressive fibrosing interstitial lung disease in anti-synthetase syndrome

OBJECTIVES

Interstitial lung disease (ILD) is common in anti-synthetase syndrome (ASS). Progressive fibrosing ILD (PF-ILD) may develop in ILD with autoimmune features. Data on PF-ILDs in ASS as a group are scarce. This study aimed to explore the characteristics and predictors of PF-ILD in ASS patients.

METHODS

This retrospective study enrolled 96 ASS-ILD patients. Baseline clinical data were collected. PF-ILD assessments were conducted at every hospital visit during windows of 24 months after initial diagnosis. Phenotypic, survival features and predictors of PF-ILD were estimated through SPSS 22.0.

RESULTS

The results revealed that 35.42% (34/96) were evaluated to be PF-ILD with a median interval time of 14.73 months. Nonspecific interstitial pneumonia was the most common radiological pattern of PF-ILD. Ground glass opacity (GGO), traction bronchiectasis and reticulation were representative high-resolution computed tomography findings of this group. Compared with the non-progressive group, PF-ILD patients had higher frequencies of anti-Ro-52 antibodies (91.18% vs 66.13%, P = 0.007) and GGO in the lower + middle and lower + middle + upper zones of the left lung, as well as lower + middle zones in the right lung (85.30% vs 54.84%, P = 0.003; 64.71% vs 38.71%, P = 0.015; 82.35% vs 58.06%, P = 0.016). Multivariate Cox analysis identified that anti-Ro-52 antibody (hazards ratio [HR] 3.55, 95% CI 1.06-11.90, P = 0.040) and GGO in left lower + middle lung zones (HR 22.11, 95% CI 1.95-250.90, P = 0.012) were independent risk factors for PF-ILD.

CONCLUSIONS

PF-ILD was associated with poor prognosis. Over one-third of ASS-ILD patients may develop to PF-ILD. Anti-Ro-52 antibody positivity and GGO in left lower + middle lung zones were independent risk factors for PF-ILD in ASS patients.

"Management of myositis associated interstitial lung disease"

Idiopathic inflammatory myopathies (IIM) are rare disorders characterised by the presence of skeletal muscle inflammation, with interstitial lung disease (ILD) being the most frequent pulmonary manifestation. The spectrum of clinical presentations of myositis related ILD (M-ILD) encompasses a chronic process to a rapidly progressive ILD (RP-ILD); which is associated with a high mortality rate. The most effective treatments remain controversial and poses a unique challenge to both rheumatologists and respiratory physicians to manage. Given the rare heterogenous nature of M-ILD, there is a paucity of data to guide treatment. The cornerstone of existing treatments encompasses combinations of immunosuppressive therapies, as well as non-pharmacological therapies. In this review, we aim to summarize the current pharmacological therapies (including its dosing regimens and side effects profiles) and non-pharmacological therapies. Based on the existing literature to date, we propose a treatment algorithm for both chronic M-ILD and RP-ILD.

Mass spectrometry-based identification of new anti-Ly and known antisynthetase autoantibodies

OBJECTIVES

To discover new and detect known antisynthetase autoantibodies (ASAs) through protein immunoprecipitation combined with gel-free liquid chromatography-tandem mass spectrometry (IP-MS).

METHODS

IP-MS was performed using sera of individuals showing features of antisynthetase syndrome (ASyS) without (n=5) and with (n=12) previously detected ASAs, and healthy controls (n=4). New candidate aminoacyl-tRNA-synthetase (ARS) autoantigens identified through unbiased IP-MS were confirmed by IP-western blot. A targeted IP-MS assay for various ASA specificities was developed and validated with sera of patients with known ASAs (n=16), disease controls (n=20) and healthy controls (n=25). The targeted IP-MS assay was applied in an additional cohort of patients with multiple ASyS features or isolated myositis without previously detected ASAs (n=26).

RESULTS

Autoantibodies to cytoplasmic cysteinyl-tRNA-synthetase (CARS1) were identified by IP-MS and confirmed by western blot as a new ASA specificity, named anti-Ly, in the serum of a patient with ASyS features. Rare ASAs, such as anti-OJ, anti-Zo and anti-KS, and common ASAs could also be identified by IP-MS. A targeted IP-MS approach for ASA detection was developed and validated. Application of this method in an additional cohort identified an additional patient with anti-OJ autoantibodies that were missed by line and dot immunoassays.

DISCUSSION

CARS1 is the dominant cognate ARS autoantigen of the newly discovered anti-Ly ASA specificity. Rare and common ASA specificities could be detected by both unbiased and targeted IP-MS. Unbiased and targeted IP-MS are promising methods for discovery and detection of autoantibodies, especially autoantibodies that target complex autoantigens.

Clinical Outcomes With and Without Plasma Exchange in the Treatment of Rapidly Progressive Interstitial Lung Disease Associated With Idiopathic Inflammatory Myopathy

BACKGROUND/OBJECTIVE

A subset of patients with idiopathic inflammatory myopathy (IIM) develops highly fatal, rapidly progressive interstitial lung disease (RP-ILD). Treatment strategies consist of glucocorticoid and adjunctive immunosuppressive therapies. Plasma exchange (PE) is an alternative therapy, but its benefit is unclear. In this study, we aimed to determine whether PE benefited outcomes for patients with RP-ILD.

METHODS

In this medical records review study, we compared baseline characteristics and clinical outcomes for 2 groups of patients with IIM-related RP-ILD: those who received and did not receive PE.

RESULTS

Our cohort consisted of 15 patients, 9 of whom received PE. Baseline demographic characteristics and severity of lung, skin, and musculoskeletal disease between the 2 groups of patients were not significantly different. Five patients required mechanical ventilation (2, PE; 3, no PE). Plasma exchange was generally a third-line adjunctive treatment option. The PE group had a longer median (interquartile range) hospitalization (27.0 [23.0-36.0] days) than the non-PE group (12.0 [8.0-14.0] days) ( p = 0.02). There was a potential benefit in 30-day mortality improvement in those receiving PE (0% vs 33%, p = 0.14), with a statistically significant improvement in 2 important composite end points including 30-day mortality or need for lung transplant (0% vs 50%, p = 0.04) and 1-year mortality or need for lung transplant or hospital readmission for RP-ILD in those receiving PE (22% vs 83%, p = 0.04).

CONCLUSIONS

Plasma exchange may be an underutilized, safe salvage therapy for patients with IIM-related RP-ILD when other immunosuppressive therapies fail.

Decrease in cell counts and alteration of phenotype characterize peripheral NK cells of patients with anti-MDA5-positive dermatomyositis

OBJECTIVE

To investigate the levels and phenotypes of peripheral natural killer (NK) cells in anti-MDA5+ dermatomyositis (DM) patients, and their association with clinical features.

METHODS

Peripheral NK cell counts (NKCCs) were retrospectively collected from 497 patients with idiopathic inflammatory myopathies and 60 healthy controls. Multi-color flow cytometry was used to determine the NK cell phenotype in additional 48 DM patients and 26 healthy controls. The association of NKCC and NK cell phenotypes with the clinical features and prognosis were analyzed in anti-MDA5+ DM patients.

RESULTS

NKCC was significantly lower in anti-MDA5+ DM patients than in those with other IIM subtypes and healthy controls. A significant decrease in NKCC was associated with disease activity. Furthermore, NKCC < 27 cells/μL was an independent risk factor for 6-month mortality in anti-MDA5+ DM patients. In addition, identification of the functional phenotype of NK cells revealed significantly increased expression of the inhibitory marker CD39 in CD56^brightCD16^dimNK cells of anti-MDA5+ DM patients. CD39⁺NK cells of anti-MDA5+ DM patients showed increased expression of NKG2A, NKG2D, Ki-67, decreased expression of Tim-3, LAG-3, CD25, CD107a, and reduced TNF-α production.

CONCLUSION

Decreased cell counts and inhibitory phenotype are significant characteristics of peripheral NK cells in anti-MDA5+ DM patients.

Anti-synthetase syndrome associated interstitial lung disease after combination dual immune checkpoint inhibition

Immune checkpoint inhibitors (ICIs) unleash potent anti-tumour responses but with frequent off-target immune-mediated adverse events (irAE). ICIs can induce a spectrum of rheumatologic manifestations including inflammatory arthritis, Sjögren's syndrome, scleroderma and systemic lupus erythematosus. Here, we describe a case of antisynthetase syndrome associated interstitial lung disease (ILD) following dual Programmed Cell Death 1 and Cytotoxic T Lymphocyte-Associated Protein 4 checkpoint inhibition in a patient with metastatic melanoma. Initial treatment course was complicated by a number of irAEs including pneumonitis, colitis and thyroiditis. Suspicion of an underlying systemic rheumatic disease was heightened by the severe, relapsing and fibrosing nature of the interstitial pneumonitis. A diagnosis of amyopathic antisynthetase syndrome was made upon detection of circulating aminoacyl-tRNA synthetase (anti-EJ) autoantibodies. Intensification of induction immunosuppression followed by maintenance mycophenolate, prednisone and monthly intravenous immunoglobulin achieved long-term disease control. Detection of de novo ICI-induced inflammatory myositis ILD requires a high index of suspicion and carries important prognostic and treatment implications.

Anti-synthetase Syndrome: A Diagnostic Dilemma

Among the various inflammatory myopathies, the anti-synthetase syndrome (ASS) is a rare entity with autoantibodies directed against aminoacyl-transfer ribonucleic acid synthetase. Its clinical spectrum ranges from myopathy and non-erosive arthritis to dyspnea and cough of pulmonary interstitial disease and from hyperkeratotic skin changes to spasms of blood vessels causing Raynaud's phenomenon. We present a case of a 21-year-old female who had been suffering from fever, night sweats, and weight loss for two years and had remained undiagnosed. She came to our hospital with new-onset muscle weakness, small joint arthralgia, and skin changes. Physical examination showed inflammation involving multiple small joints and characteristic hyperkeratotic skin changes in the distal and lateral phalanges of the hands and feet. Raised creatine phosphokinase levels indicated the possibility of myositis along with positive anti-nuclear antibodies, suggesting an autoimmune rheumatic disorder. Inflammatory myositis was later confirmed on biopsy. Further investigations revealed positive anti-Jo1 antibodies. The diagnosis of ASS was made despite the absence of pulmonary signs and symptoms. The patient was promptly started on prednisone and azathioprine. She showed some improvement in muscle weakness at the end of two months and continues to improve albeit slowly. Due to the lack of awareness about the rare disease among the non-rheumatologists, there was a significant delay in the patient's diagnosis. It is, therefore, important for primary care physicians to obtain a comprehensive history and perform a detailed clinical examination to make timely referrals to specialized healthcare professionals.

Muscle pathology of antisynthetase syndrome according to antibody subtypes

Identification of antisynthetase syndrome (ASS) could be challenging due to inaccessibility and technical difficulty of the serology test for the less common non-Jo-1 antibodies. This study aimed to describe ASS antibody-specific myopathology and evaluate the diagnostic utility of myofiber HLA-DR expression. We reviewed 212 ASS muscle biopsies and compared myopathologic features among subtypes. Additionally, we compared their HLA-DR staining pattern with 602 non-ASS myositis and 140 genetically confirmed myopathies known to have an inflammatory component. We used t-test and Fisher's exact for comparisons and used sensitivity, specificity, positive and negative predictive values to assess the utility of HLA-DR expression for ASS diagnosis. RNAseq performed from a subset of myositis cases and histologically normal muscle biopsies was used to evaluate interferon (IFN)-signaling pathway-related genes. Anti-OJ ASS showed prominent myopathology with higher scores in muscle fiber (4.6 ± 2.0 vs. 2.8 ± 1.8, p = 0.001) and inflammatory domains (6.8 ± 3.2 vs. 4.5 ± 2.9, p  = 0.006) than non-OJ ASS. HLA-DR expression and IFN-γ-related genes upregulation were prominent in ASS and inclusion body myositis (IBM). When dermatomyositis and IBM were excluded, HLA-DR expression was 95.4% specific and 61.2% sensitive for ASS with a positive predictive value of 85.9% and a negative predictive value of 84.2%; perifascicular HLA-DR pattern is common in anti-Jo-1 ASS than non-Jo-1 ASS (63.1% vs. 5.1%, p < 0.0001). In the appropriate clinicopathological context, myofiber HLA-DR expression help support ASS diagnosis. The presence of HLA-DR expression suggests involvement of IFN-γ in the pathogenesis of ASS, though the detailed mechanisms have yet to be elucidated.

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.

Recurrent Exacerbations and Evolution into Polymyositis in a Patient with Interstitial Pneumonia with Autoimmune Features: A Case Report and Literature Review

Interstitial pneumonia with autoimmune features (IPAF) is a new disease entity proposed in 2015. Numerous questions regarding IPAF require clarification, including diagnostic criteria, standard managements for stable disease and exacerbation, and prognosis. We report a case of a 67-year-old Asian woman who presented with progressive dyspnea. Chest computed tomography (CT) scans revealed nonspecific interstitial pneumonia. Serologic testing indicated positive anti-Jo-1 without presence of extrathoracic manifestations. An IPAF diagnosis was made after a multidisciplinary discussion. The patient experienced a severe exacerbation requiring mechanical ventilation, and she was successfully salvaged with methylprednisolone pulse therapy and single-dose cyclophosphamide. During the one-year follow-up, she reported bilateral leg muscle weakness with noticeably elevated serum creatine kinase, suggesting polymyositis. The development of malignancy was also noted 15 months after the initial presentation, and the patient eventually died. This report demonstrated successful salvage treatment with glucocorticoid pulse therapy for IPAF with acute exacerbation. However, the maintenance therapy failed to control disease progression. The treatment strategies for exacerbation and stable disease in IPAF remain unknown and need further studies. Given the high risk of evolution into a defined connective tissue disease (CTD), regular evaluation of the clinical features and biomarkers of CTDs is essential for patients with IPAF.

Successful treatment of rapid progressive interstitial lung disease in a case of anti-Zo antibody positive anti-synthetase syndrome

BACKGROUND

Anti-synthetase syndrome (ASS) is a chronic multisystemic autoimmune disease characterized by detectable anti-aminoacyl-transfer-RNA antibodies. Interstitial lung disease (ILD) in anti-synthetase syndrome patients is often severe and rapidly progressive. Anti-Zo (phenylalanyl) antibody is reported rarely in ASS. Therefore, the appropriate treatment of anti-Zo positive ASS is unclear.

CASE PRESENTATION

Here we present a case of anti-Zo-positive ASS with rapid progressive ILD (RP-ILD) in a Chinese patient successfully treated with a combination of systemic corticosteroids and tacrolimus.

CONCLUSION

We reviewed 13 anti-Zo-positive ASS patients (including our case) and summarized clinical features that have some differences with other ASS. Anti-Zo-positive ASS is a rare autoimmune disease with a high burden of ILD, is often severe and rapidly progressive. Corticosteroids with tacrolimus may improve patient outcomes in anti-Zo antibody positive ASS with RP-ILD.

Antisynthetase Syndrome in a Patient with Pulmonary Embolism and Nonbacterial Thrombotic Endocarditis

Antisynthetase syndrome is a rare autoimmune disease within the subset of idiopathic inflammatory myopathies. The diagnostic criteria include the presence of an aminoacyl-tRNA synthetase antibody, and typical clinical findings, including myositis, mechanic's hands, Raynaud phenomenon, unexplained fever, and interstitial lung disease. We describe a case of a 59-year-old male who presented with a 1-month history of progressive purplish discoloration and pain of the fingertips, dyspnea, cough, weight loss, fatigue, and who developed progressive proximal muscle weakness and dysphagia. Investigations revealed pulmonic valve and mitral valve marantic endocarditis, pulmonary embolism, myositis, organizing pneumonia, and elevation of anti-OJ antibodies. He was diagnosed with antisynthetase syndrome and treated with high dose corticosteroids and mycophenolate mofetil with a fair response.

Cancer associated autoantibodies in idiopathic inflammatory myopathies: A retrospective cohort from a single center in China

OBJECTIVES

Idiopathic inflammatory myopathies (IIMs) are systemic, heterogeneous diseases, which mainly affect skeletal muscle. Myositis with cancer is often referred to as cancer-associated myositis (CAM), which is associated with poor prognosis. This study aimed to determine the cancer associated myositis-specific autoantibodies (MSAs) and to elucidate their associations with clinical features in Chinese patients with IIMs.

METHODS

This retrospective study enrolled 312 patients with IIMs who were treated at Tianjin Medical University General Hospital, China, from January 2015 to December 2020. Clinical data were collected. Serum MSAs, including anti-Mi-2, anti-TIF1-γ, anti-NXP2, anti-SAE, anti-MDA5, anti-SRP, anti-Jo-1, anti-PL-7, anti-PL-12, anti-OJ, anti-EJ and anti-HMGCR antibodies were detected. Cancer-associated MSAs, their phenotypic and survival features were estimated through SPSS 20.0.

RESULTS

The results revealed that anti-TIF1-γ antibody and anti-SAE antibody were cancer-associated autoantibodies with odds ratios (95% CI) of 8.70 (3.35-22.64) and 22.31 (4.32-115.05), respectively. Skin lesions, proximal weakness, dysphagia and dysarthria were observed more frequently in patients carrying anti-TIF1-γ antibody. By contrast, patients with anti-TIF1-γ antibody had a lower frequencies of fever, arthritis/arthralgia and interstitial lung disease (ILD). Anti-TIF1-γ antibody positive CAM comprised about half of CAM entities and had the characteristic of close temporal association with cancer detection/recurrence. Female-dominant, common reproductive system tumors were other clinical features of this subset. Besides, patients with anti-TIF1-γ antibody positive had significantly lower survival rates than the anti-TIF1-γ antibody negative group.

CONCLUSIONS

Anti-TIF1-γ antibody and anti-SAE antibody were cancer-associated autoantibodies. Anti-TIF1-γ antibody positive CAM was a subset that comprised about half of CAM entities and had the characteristic of poor prognosis.

Perioperative Management of Antisynthetase Syndrome: A Case Report

Antisynthetase syndrome is a rare idiopathic inflammatory multisystem disorder, which can lead to serious postoperative complications. Due to its low incidence, there is little literature on its anesthetic management. However, patients with this disease can suffer from serious complications secondary to muscle weakness and respiratory complications. Although the intraoperative and the immediate postoperative periods may be uneventful, complications may appear later. The characteristics of the disease can lead to a misdiagnosis in the case of respiratory acute failure. The objective of this clinical report is to discuss the perioperative management of patients suffering from antisynthetase syndrome, assess the usefulness of postoperative monitoring, and evaluate alternatives that could have been carried out to prevent the fatal outcome reported in this narrative.

Autoantigenic properties of the aminoacyl tRNA synthetase family in idiopathic inflammatory myopathies

OBJECTIVES

Autoantibodies are thought to play a key role in the pathogenesis of idiopathic inflammatory myopathies (IIM). However, up to 40% of IIM patients, even those with clinical manifestations of anti-synthetase syndrome (ASSD), test seronegative to known myositis-specific autoantibodies. We hypothesized the existence of new potential autoantigens among human cytoplasmic aminoacyl tRNA synthetases (aaRS) in patients with IIM.

METHODS

Plasma samples from 217 patients with IIM according to 2017 EULAR/ACR criteria, including 50 patients with ASSD, 165 without, and two with unknown ASSD status were identified retrospectively, as well as age and gender-matched sera from 156 population controls, and 219 disease controls. Patients with previously documented ASSD had to test positive for at least one of the five most common anti-aaRS autoantibodies (anti-Jo1, -PL7, -PL12, -EJ, and -OJ) and present with one or more of the following clinical manifestations: interstitial lung disease, myositis, arthritis, Raynaud's phenomenon, fever, or mechanic's hands. Demographics, laboratory, and clinical data of the IIM cohort (ASSD and non-ASSD) were compared. Samples were screened using a multiplex bead array assay for presence of autoantibodies against a panel of 117 recombinant protein variants, representing 33 myositis-related proteins, including all nineteen cytoplasmic aaRS. Prospectively collected clinical data for the IIM cohort were retrieved and compared between groups within the IIM cohort and correlated with the results of the autoantibody screening. Principal component analysis was used to analyze clinical manifestations between ASSD, non-ASSD groups, and individuals with novel anti-aaRS autoantibodies.

RESULTS

We identified reactivity towards 16 aaRS in 72 of the 217 IIM patients. Twelve patients displayed reactivity against nine novel aaRS. The novel autoantibody specificities were detected in four previously seronegative patients for myositis-specific autoantibodies and eight with previously detected myositis-specific autoantibodies. IIM individuals with novel anti-aaRS autoantibodies (n = 12) all had signs of myositis, and they had either muscle weakness and/or muscle enzyme elevation, 2/12 had mechanic's hands, 3/12 had interstitial lung disease, and 2/12 had arthritis. The individuals with novel anti-aaRS and a pathological muscle biopsy all presented widespread up-regulation of major histocompatibility complex class I. The reactivities against novel aaRS could be confirmed in ELISA and western blot. Using the multiplex bead array assay, we could confirm previously known reactivities to four of the most common aaRS (Jo1, PL12, PL7, and EJ (n = 45)) and identified patients positive for anti-Zo, -KS, and -HA (n = 10) that were not previously tested. A low frequency of anti-aaRS autoantibodies was also detected in controls.

CONCLUSION

Our results suggest that most, if not all, cytoplasmic aaRS may become autoantigenic. Autoantibodies against new aaRS may be found in plasma of patients previously classified as seronegative with potential high clinical relevance.

Utility of Myositis-Specific Autoantibodies for Treatment Selection in Myositis

Purpose of Review

Autoimmune myopathies (IMs) are a group of diseases characterized by muscle weakness and inflammatory infiltrates on the muscle biopsy. 'However, muscle involvement is not always present and other organs and tissues (lung, skin, and joints) are commonly affected. The most accepted classification for IM includes dermatomyositis, sporadic inclusion body myositis, immune-mediated necrotizing myopathy, polymyositis, and overlap myositis. Seventy percent of the autoantibodies that IM patients have are myositis-specific autoantibodies (MSAs). Importantly, MSAs are associated with specific clinical phenotypes in IM patients. The therapy of IMs consists of glucocorticoids, immunosuppressants, biologic, and immunomodulatory drugs, but there is recent evidence that patients with some types of MSAs respond better to certain treatments. The purpose of this review is to summarize the IM treatment from an autoantibody perspective.

Recent Findings

Each MSA is maybe associated with the activation of specific pathogenic pathways which can be effectively targeted by specific drugs. The last few years have shown multiple examples of successful treatments for each MSA group of patients as we will describe in the following paragraphs.

Summary

The adverse effects of the IM therapeutic agents and some patients' refractoriness call for a continued search for better and more targeted therapies. MSA groups should be considered for a treatment decision.

A rare presentation of anti-synthetase syndrome requiring intensive care in the midst of a COVID wave

A 24-year-old female with pneumonia two months prior presented with fever, cough and worsening dyspnea in the midst of a COVID-19 spike. Her initial episode was treated as COVID-19 pneumonia. On presentation, her chest CT was suggestive of bilateral lower zone organizing pneumonia with mild fibrosis and was attributed to post COVID sequelae with an infective exacerbation. Oral steroids and antibiotics were administered following which she had initial improvement and then subsequent deterioration requiring ICU care. A detailed clinical examination (in-person and virtually) at this point revealed the presence of pigmented rashes over the knuckles and weakness of hip muscles. Laboratory work showed elevated creatine kinase levels, positive anti-Ro and anti-Jo1 antibodies which pointed to a diagnosis of anti-synthetase syndrome (ASS). Unique attributes of this case include younger age of presentation in an atypical ethnic group and possibly incited by COVID-19 infection in the peak of a COVID-19 wave. The work-up, diagnosis and initial management of this patient was carried out through a hybrid ICU model which functioned as a traditional ICU in the day and a tele-ICU at night with an appropriate network of sub-specialists including Rheumatologists consulting, thus highlighting a collaborative model in a low resource setting capable of managing rare cases even in the midst of increasing critical care needs during the pandemic.

Antisynthetase syndrome and interstitial lung disease: A case report

Introduction

Myositis, Raynaud's phenomenon, fever, interstitial lung disease, mechanic's hands, and arthropathy are symptoms of Antisynthetase Syndrome (ASS), which is defined by the development of antibodies against t-ribonucleic acid (RNA) synthetase, particularly anti-Jo-1.

Case presentation

The case is about 29 years female with 1 month history of non-productive cough and dyspnea on exertion which was later diagnosed as ASS.

Discussion

The diagnosis of an inflammatory myopathy is based on clinical findings such as subacute development of symmetrical muscle weakness and signs such as laboratory investigations revealing skeletal muscle inflammation. Creatinine phosphokinase (CPK) is mainly used to demonstrate skeletal muscle involvement.

Conclusion

Interstitial lung disease is a frequent occurrence and is associated with a bad prognosis during the course of antisynthetase syndrome.

Promising Neutrophil-Associated Biomarkers in Lung Diseases of Patients with Antisynthetase Syndrome and Dermatomyositis

Objectives

Antisynthetase syndrome (ASS) and dermatomyositis (DM) are serious autoimmune diseases, with lungs being the most frequently involved organ and sometimes fatal. This study is aimed at clarifying the role of neutrophil-associated biological markers in suggesting ASS and DM-associated respiratory infections and interstitial lung diseases.

Methods

We carried out a retrospective review of the medical records of 46 cases of ASS and DM diagnosed at the Second Hospital of Zhejiang University College of Medicine, between January 2017 and December 2020. Serum myeloperoxidase (MPO), neutrophil elastase (NE), α1 anti-trypsin (AAT), and interleukin-6 (IL-6) were also detected.

Results

Gottron's sign is characteristic of dermatomyositis, while polyarthritis is more characteristic of ASS. Pulmonary function is worse in ASS than in DM patients. Patients with ASS and DM had abnormal lymphocyte and neutrophil counts compared to healthy subjects, but not in relation to lung function and rapid progression of interstitial lung disease (RP-ILD). Elevated serum NE, MPO, and IL-6 levels are suggestive of respiratory infections, whereas decreased circulating IL-6 is predictive of RP-ILD.

Conclusion

Our study identified the neutrophil-associated biomarkers MPO, NE, and IL-6 as promising indicators with different suggestive roles in respiratory infections and interstitial lung diseases in patients with ASS and DM.

A multidisciplinary approach to the diagnosis of antisynthetase syndrome

Antisynthetase syndrome is a subtype of idiopathic inflammatory myopathy, strongly associated with the presence of interstitial lung disease. Diagnosis is made by identifying myositis-specific antibodies directed against aminoacyl tRNA synthetase, and relevant clinical and radiologic features. Given the multisystem nature of the disease, diagnosis requires the careful synthesis of subtle clinical and radiological features with the interpretation of specialized autoimmune serological testing. This is provided in a multidisciplinary environment with input from rheumatologists, respiratory physicians, and radiologists. Differentiation from other idiopathic interstitial lung diseases is key; treatment and prognosis differ between patients with antisynthetase syndrome and idiopathic interstitial lung disease. In this review article, we look at the role of the multidisciplinary team and its individual members in the initial diagnosis of the antisynthetase syndrome, including the role of physicians, radiologists, and the wider team.

Evaluation of Interstitial Lung Disease in Idiopathic Inflammatory Myopathies Through Semiquantitative and Quantitative Analysis of Lung Computed Tomography

PURPOSE

To perform a semiquantitative and quantitative analysis of interstitial lung disease (ILD), through computed tomography (CT), in different serological subgroups of idiopathic inflammatory myopathies (IIM) patients, to find radiologic and clinical differences of disease related to serology.

MATERIALS AND METHODS

This was a prospective study, which included 98 IIM patients, divided into serological subgroups: anti-aminoacyl-transfer-RNA-synthetases (anti-ARS) positive and myositis-specific autoantibodies (MSA) negative.For each baseline CT the total semiquantitative score of Warrick (WS) and the automated software (Computer-Aided Lung Informatics for Pathology Evaluation and Rating) quantitative scores interstitial lung disease % (ILD%) and vascular-related structure % (VRS%) were calculated. Pulmonary function tests included total lung capacity % (TLC%), forced vital capacity % (FVC%), and diffusing capacity of the lung for carbon monoxide % (DLCO%).

RESULTS

Inverse correlations ( P <0.001) between the radiologic scores and the functional scores DLCO% and TLC% were found, the most relevant being between ILD% and DLCO% (ρ=-0.590), VRS% and DLCO% (ρ=-0.549), and WS and DLCO% (ρ=-0.471).Positive correlations between ILD% and VRS% (ρ=0.916; P <0.001), WS and ILD% (ρ=0.663; ρ<0.001), and WS and VRS% (ρ=0.637; P <0.001) were obtained.Statistically significant higher values of WS, ILD%, and VRS% were found in the anti-ARS group (WS=15; ILD%=11; VRS%=3.5) compared with the MSA negative one (WS=2.5; ILD%=0.84; VRS%=2.2).The nonspecific interstitial pneumonia pattern was dominant. No statistically significant differences emerged at pulmonary function tests.

CONCLUSIONS

In this study, ILD in anti-ARS-positive and MSA-negative groups was defined through semiquantitative and quantitative analysis of lung CT. The inverse correlations between the radiologic scores and TLC% and DLCO% ( P <0.001) confirm the role of lung CT in the evaluation of ILD in IIM.

Das Anti-Synthetase-Syndrom

Das Anti-Synthetase-Syndrom (ASyS) ist eine klinisch heterogene und seltene Autoimmunerkrankung, in der es zur Bildung von Autoantikörpern gegen Aminoacyl-tRNA-Synthetasen kommt. Klinisch findet man klassischerweise die Trias aus Myositis, Arthritis und prognosebestimmender interstitieller Lungenerkrankung. Wir berichten über einen 30-jährigen Patienten mit rezidivierenden Fieberschüben, symmetrischen Gelenkschwellungen, Muskelbeschwerden und progredienter Belastungsdyspnoe, bei dem in Zusammenschau des Nachweises von Anti-Jo-1-Antikörpern die Diagnose eines ASyS gestellt wurde. Unter einer Kombinationstherapie aus Glukokortikoiden und Azathioprin konnte eine Remission der Myositis und Arthritis sowie eine Regredienz der ILD-assoziierten Veränderungen im Thorax-CT erzielt werden. Die frühzeitige Erkennung der Erkrankung und die Bestimmung myositisspezifischer Antikörper sind für die Diagnostik und Prognostik der Erkrankung von zentraler Bedeutung. Betroffene Patient:innen können dadurch rasch einer adäquaten, auf ihre Organmanifestation abgestimmten Therapie zugeführt werden.

Integrating 16S rRNA gene sequencing and metabolomics to evaluate the association between gut microbiota and serum metabolites in patients with myositis

AIMS

Gut microbiota and metabolites have a profound impact on the maintenance of body health. In this study, we assessed the association between gut microbiota and serum metabolite changes in myositis using 16S rRNA gene sequencing and metabolomics to provide new ideas for screening and treating myositis.

METHODS AND RESULTS

Blood and fecal samples were collected from twenty myositis patients and twenty healthy control subjects. Then, 16S rRNA gene sequencing, enzyme-linked immunosorbent assays, and untargeted metabolomics study were performed to evaluate the relationship between gut microbiota and serum metabolites in patients with myositis. Compared to healthy control subjects, the blood samples from the patients with myositis had elevated levels of interleukin-4 (IL-4), tumor necrosis factor-α (TNF-α), and malondialdehyde (MDA), and decreased superoxide dismutase (SOD) levels. The increase in Bacteroidota (including Bacteroides and Parabacteroides, but not Prevotella) and the decrease in Firmicutes in the patients were accompanied by functional changes in amino acid and lipid metabolism. The gut microbiota (Bacteroides and Parabacteroides) were negatively correlated with the differential serum metabolites (glutamate and taurine). The differential serum metabolites (glutamate, pyrrolidonecarboxylic acid, and taurine) were also correlated with inflammatory factors (IL-4 and TNF-α) and oxidative stress indexes (MDA and SOD).

CONCLUSION

Dysbiosis of gut microbiota in patients with myositis was accompanied by changes in inflammatory factors, oxidative stress indexes, and small molecule metabolites in serum.

SIGNIFICANCE AND IMPACT OF STUDY

Blood and fecal biomarkers could be used for screening myositis.

Physical exercise for dermatomyositis and polymyositis: a systematic review and meta-analysis

Trials regarding physical exercise in dermatomyositis (DM) and polymyositis (PM) are heterogeneous. We aimed to summarize and critically analyze the available evidence to support the hypothesis that exercise is safe and improves strength and aerobic capacity. We performed a systematic review of clinical trials regarding physical exercise in dermatomyositis and polymyositis, without time restriction. We included studies from MEDLINE, EMBASE, SciELO, and Web of Science, published in English, Portuguese, or Spanish, and reporting outcomes related to safety, muscle performance, or aerobic capacity. The certainty of evidence was evaluated in accordance with the GRADE methodology. Meta-analysis was carried using pooled standardized mean differences (SMD) with 95% confidence interval as effect measure. We included 19 studies and 298 patients. The certainty of evidence was downgraded due to unbalanced confounding variables. The meta-analysis demonstrated improvements in strength (SMD [95% CI] = 0.61 [0.37-0.85], P < .00001) and aerobic capacity (SMD [95% CI] = 0.82 [0.29-1.34], P = .002), with no difference in creatine phosphokinase levels (SMD [95% CI] =  - 0.23 [- 0.5-0.03], P = .08) after the interventions. No exacerbation was reported, and results were favorable in all stages of disease and ages, but might be different in the future with new classification criteria for PM and the inclusion of other idiopathic inflammatory myopathies. Novel approaches such as blood flow restriction training and aquatic plyometric exercises were promising. Physical exercise in DM/PM patients of all ages is probably safe and moderately improves muscle strength and aerobic capacity.

Autoantibodies: Pathogenic or epiphenomenon

Idiopathic inflammatory myopathies (IIM) are heterogeneous autoimmune diseases. There are distinct subgroups, including antisynthetase syndrome, dermatomyositis, polymyositis, immune-mediated necrotizing myopathy, and sporadic inclusion body myositis. In patients with IIM, autoantibodies are present in up to 80% of the patients. These autoantibodies are often characterized as myositis-specific autoantibodies (MSA) or myositis-associated autoantibodies (MAA). The recognition of the importance of autoantibodies, especially MSA, is increasing in recent years. In this chapter, we provide an overview of the MSAs, including some new autoantibodies of interest as they target mainly muscle-specific autoantigen, in clinical classification, the measurement of the disease activity, and a possible role in the pathogenesis in the patients with IIM.

Antisynthetase syndrome with rare EJ-1 antibodies with antiphospholipid syndrome

We describe the first case of antisynthetase syndrome (ASS) with antibodies to anti-glycyl tRNA synthetase (EJ-1) with antiphospholipid syndrome (APLS). A 66-year-old man presented with progressive dyspnoea, fever, dry cough and proximal muscle weakness over several months on a background of cryptogenic organizing pneumonia. Examination revealed bibasal fine chest crackles, proximal muscle weakness of the upper and lower limbs, digital skin thickening and facial telangiectasias. Creatine kinase was elevated and autoimmune screening was positive for anti-EJ-1, anti-beta-2-glycoprotein, anti-Ro and anti-La antibodies. Computed tomography of the chest revealed a usual interstitial pneumonia pattern and a ventilation-perfusion scan demonstrated scintigraphic evidence of bilateral pulmonary emboli. A diagnosis of ASS and APLS was made. Immunosuppressive therapy including pulsed methylprednisolone, rituximab and mycophenolate was commenced with improvement in symptoms. This case highlights the importance of evaluation for ASS in idiopathic interstitial pneumonia, and APLS in ASS patients.

Clinical characteristics of idiopathic interstitial pneumonias with anti-Ro52/tripartite motif-containing 21 antibodies

Antibodies to Ro52/tripartite motif-containing 21 (TRIM21), referred to as anti-Ro52, are found in patients diagnosed with diverse systemic autoimmune rheumatic disease and associated with interstitial lung diseases. However, little is known about the clinical characteristics of anti-Ro52 in patients with idiopathic interstitial pneumonias (IIPs). We aimed to analyze the prevalence, co-existent autoantibodies, and clinical characteristics of anti-Ro52 in patients with IIP. The study enrolled 288 patients diagnosed with IIP. Clinical, laboratory and radiographic findings of IIP patients were compared between anti-Ro52 positives and negatives. Anti-Ro52 (20/288; 6.9%), anti-ARS (18/288; 6.3%), and anti-Ro60/SS-A (16/288; 5.6%) were the most common autoantibodies detected in IIP patients. Among 20 IIP patients who had anti-Ro52, anti-ARS was present in 8 (40%) patients. The criteria for interstitial pneumonia with autoimmune features (IPAF) were significantly better fulfilled by patients with anti-Ro52 than those without (P = 0.001). Meeting serological domain (P < 0.001) and Raynaud’s phenomenon (P = 0.009) were significantly more common in the anti-Ro52-positive patients. Anti-Ro52-positive IIP patients have clinical features consistent with IPAF. Anti-Ro52 may have an important role in detecting the autoimmune phenotype in IIP patients.

Possible future avenues for myositis therapeutics: DM, IMNM and IBM

Idiopathic inflammatory myopathies (IIMs) represent a heterogeneous group of systemic autoimmune diseases characterized by immune-mediated muscle injury. As insights into pathogenesis of IIM evolve, novel therapeutic strategies have become available to optimize outcomes. Herein, we summarize novel and emerging strategies in the management of dermatomyositis (DM), immunemediated necrotizing myopathy (IMNM), and inclusion body myositis (IBM).

Effect size of rituximab on pulmonary function in the treatment of connective-tissue disease-related interstitial lung disease: a systematic review and meta-analysis

BACKGROUND

Rituximab (RTX) has been previously reported as directed treatment in patients with connective-tissue disease-related interstitial lung diseases (CTD-ILD). A systematic assessment of treatment effect size on pulmonary function outcomes and related adverse effects in patients with CTD-ILD has not been previously reported.

METHODS

We performed a systematic review and meta-analysis of published reports from PubMed, Embase, and Cochrane Libraries. Randomized and non-randomized controlled trials, case-control, cohort, and case series (with five or more cases) containing individual pulmonary function data and adverse effects were included. Study endpoints were pre- and post-treatment change in percent predicted forced vital capacity (FVC %) and diffusion capacity for carbon monoxide (DLCO%), along with reported drug-related adverse events.

RESULTS

Twenty studies totaling 411 patients were identified with 14 included in the meta-analysis of pulmonary function and six in the descriptive review. Random effects meta-analysis of pre- and post-treatment pulmonary function findings demonstrated increases in FVC% (n = 296) (mean difference (MD) 4.57%, [95% CI 2.63-6.51]) and DLCO% (n = 246) (MD 5.0% [95% CI 2.71-7.29]) after RTX treatment. RTX treatment-related adverse effects were reported in 13.6% of the pooled cohort.

CONCLUSIONS

A systematic assessment of post-treatment effect size suggests a potential role for RTX in stabilizing or improving lung function in patients with CTD-ILD, with a modest but not insignificant adverse effect profile.

Antisynthetase Syndrome Post Shingrix and Pneumovax Vaccinations, Possible Correlation

This is a case report of a patient who developed acute progressive shortness of breath that started two days following the administration of Shingrix and Pneumovax vaccinations. Eight days after the onset of his symptoms he was diagnosed with acute interstitial pneumonitis based on CT scan of the chest which later appeared to be consistent with the diagnosis of antisynthetase syndrome in light of findings consistent with mechanic's hands on examination, elevated Anti-Jo-1 antibody titers and aldolase on laboratory studies.

Aminoacyl-tRNA Synthetases: On Anti-Synthetase Syndrome and Beyond

Anti-synthetase syndrome (ASSD) is an autoimmune disease characterized by the presence of autoantibodies targeting one of several aminoacyl t-RNA synthetases (aaRSs) along with clinical features including interstitial lung disease, myositis, Raynaud’s phenomenon, arthritis, mechanic’s hands, and fever. The family of aaRSs consists of highly conserved cytoplasmic and mitochondrial enzymes, one for each amino acid, which are essential for the RNA translation machinery and protein synthesis. Along with their main functions, aaRSs are involved in the development of immune responses, regulation of transcription, and gene-specific silencing of translation. During the last decade, these proteins have been associated with cancer, neurological disorders, infectious responses, and autoimmune diseases including ASSD. To date, several aaRSs have been described to be possible autoantigens in different diseases. The most commonly described are histidyl (HisRS), threonyl (ThrRS), alanyl (AlaRS), glycyl (GlyRS), isoleucyl (IleRS), asparaginyl (AsnRS), phenylalanyl (PheRS), tyrosyl (TyrRS), lysyl (LysRS), glutaminyl (GlnRS), tryptophanyl (TrpRS), and seryl (SerRS) tRNA synthetases. Autoantibodies against the first eight autoantigens listed above have been associated with ASSD while the rest have been associated with other diseases. This review will address what is known about the function of the aaRSs with a focus on their autoantigenic properties. We will also describe the anti-aaRSs autoantibodies and their association to specific clinical manifestations, and discuss their potential contribution to the pathogenesis of ASSD.

Clinical and pathological features of immune-mediated necrotising myopathies in a single-centre muscle biopsy cohort

OBJECTIVE

Immune-mediated necrotising myopathy (IMNM) is a subset of idiopathic inflammatory myopathies (IIM) characterized by significantly elevated creatine kinase level, muscle weakness and predominant muscle fibre necrosis in muscle biopsy. This study aimed to investigate the clinical and pathological characteristics of patients with IMNM in a single-centre muscle biopsy cohort.

METHODS

A total of 860 patients who had muscle biopsy reports in our centre from May 2008 to December 2017 were enrolled in this study. IMNM was diagnosed according to the 2018 European Neuromuscular Centre (ENMC) clinicopathological diagnostic criteria for IMNM.

RESULTS

The muscle biopsy cohort consisted of 531 patients with IIM (61.7%), 253 patients with non-IIM (29.4%), and 76 undiagnosed patients (8.8%). IIM cases were classified as IMNM (68[7.9%]), dermatomyositis (346[40.2%]), anti-synthetase syndrome (82[9.5%]), polymyositis (32[3.7%]), and sporadic inclusion body myositis (3[0.3%]). Limb girdle muscular dystrophy (LGMD) 2B and lipid storage myopathy (LSM) are the two most common non-IIM disorders in our muscle biopsy cohort. IMNM patients had a higher onset age (41.57 ± 14.45 vs 21.66 ± 7.86 and 24.56 ± 10.78, p < .0001), shorter duration (21.79 ± 26.01 vs 66.69 ± 67.67 and 24.56 ± 10.78, p < .0001), and more frequent dysphagia (35.3% vs. 3.4 and 6.3%, p = .001) than LGMD 2B and LSM patients. Muscle biopsy from IMNM showed more frequent muscle fibre necrosis (95.6% vs 72.4 and 56.3%, p < .0001), overexpression of major histocompatibility complex-I on sarcolemma (83.8% vs 37.9 and 12.9%, p < .0001), and CD4+ T cell endomysia infiltration (89.7% vs 53.6 and 50%, p < .0001) compared with those from LGMD 2B and LSM patients.

CONCLUSIONS

It is easy to distinguish IMNM from other IIM subtypes according to clinical symptoms and myositis specific antibodies profiles. However, distinguishing IMNM from disorders clinically similar to non-IIM needs combined clinical, serological and pathological features.

A New Method for the Assessment of Myalgia in Interstitial Lung Disease: Association with Positivity for Myositis-Specific and Myositis-Associated Antibodies

In this study, it was found that myositis-specific and myositis-associated antibodies (MSAs and MAAs) improved the recognition of idiopathic inflammatory myopathies (IIMs) in interstitial lung disease (ILD) patients. The objective of this study is to propose a clinical method to evaluate myalgia in respiratory settings as a possible tool for the recognition of MSA/MAA positivity in ILD patients. We prospectively enrolled 167 ILD patients with suspected myositis, of which 63 had myalgia evoked at specific points (M+ILD+). We also enrolled in a 174 patients with only myalgia (M+ILD-) in a rheumatological setting. The patients were assessed jointly by rheumatologists and pulmonologists and were tested for autoantibodies. M+ILD+ patients were positive for at least one MAA/MSA in 68.3% of cases, as were M-ILD+ patients in 48.1% of cases and M+ILD- patients in 17.2% of cases (p = 0.01 and <0.0001, respectively). A diagnosis of IIM was made in 39.7% of M+ILD+ patients and in 23.1% of the M-ILD+ group (p = 0.02). Myalgia was significantly associated with positivity for MSA/MAAs in ILD patients (p = 0.01, X2: 6.47). In conclusion, myalgia in ILD patients with suspected myositis is associated with MSA/MAA positivity, and could support a diagnosis of IIM. A significant proportion of M+ILD- patients also had MSA/MAA positivity, a phenomenon warranting further study to evaluate its clinical meaning.

Screening for Anti-HMGCR Antibodies in a Large Single Myositis Center Reveals Infrequent Exposure to Statins and Diversiform Presentation of the Disease

Background

The objective of this study is to assess the frequency of autoantibodies against 3-hydroxy-3-methyl-glutaryl-coenzyme A reductase (HMGCR) in a single center myositis cohort and to analyze associations with statin exposure, clinical features, and outcome of disease course.

Methods

A total of 312 patients with idiopathic inflammatory myopathies (IIMs) followed at the rheumatology clinic, Karolinska University Hospital, were identified in the Euromyositis registry between 1988 and 2014 and were classified according to the 2017 European Alliance of Associations for Rheumatology/American College of Rheumatology (EULAR/ACR) criteria. Available serum samples were analyzed for anti-HMGCR autoantibodies by ELISA. Positive sera were confirmed by immunoprecipitation. Clinical data were extracted from Euromyositis registry and medical records. Muscle samples were examined by two pathologists blinded to the subjects' autoantibody status.

Results

Of 312 patients, 13 (4.3%) were positive for anti-HMGCR. Two of the 13 (15%) anti-HMGCR-positive patients had histories of statin use versus 12 (4.2%) in the anti-HMGCR-negative group. In the anti-HMGCR-positive group, five (38%) had a clinical phenotype compatible with dermatomyositis. Muscle biopsies of patients with HMGCR autoantibodies showed findings consistent with immune-mediated necrotizing myopathy in all cases except for one. Five (38%) patients required treatment with intravenous immunoglobulin compared to seven (2.3%) without this antibody. At the last visit, seven patients had chronic, active disease course, and five of 13 patients were in remission, including three without treatment.

Conclusions

Patients with IIM related to anti-HMGCR autoantibodies may present with a wide range of symptoms, more than previously anticipated. When a broad approach to screening for these antibodies is applied, only a minority of patients was found to have previous statin exposure. The results of this study justify the addition of anti-HMGCR autoantibodies to routine diagnostic procedures in patients with myositis.

Single-Cell Transcriptomics Reveals Peripheral Immune Responses in Anti-Synthetase Syndrome-Associated Interstitial Lung Disease

OBJECTIVE

Interstitial lung diseases (ILDs) secondary to anti-synthetase syndrome (ASS) greatly influence the prognoses of patients with ASS. Here we aimed to investigate the peripheral immune responses to understand the pathogenesis of this condition.

METHODS

We performed single-cell RNA sequencing (scRNA-seq) of peripheral blood mononuclear cells (PBMCs) from 5 patients with ASS-ILD and 3 healthy donors (HDs). Flow cytometry of PBMCs was performed to replenish the results of scRNA-seq.

RESULTS

We used scRNA-seq to depict a high-resolution visualization of cellular landscape in PBMCs from patients with ASS-ILD. Patients showed upregulated interferon responses among NK cells, monocytes, T cells, and B cells. And the ratio of effector memory CD8 T cells to naïve CD8 T cells was significantly higher in patients than that in HDs. Additionally, Th1, Th2, and Th17 cell differentiation signaling pathways were enriched in T cells. Flow cytometry analyses showed increased proportions of Th17 cells and Th2 cells, and decreased proportion of Th1 cells in patients with ASS-ILD when compared with HDs, evaluated by the expression patterns of chemokine receptors.

CONCLUSIONS

The scRNA-seq data analyses reveal that ASS-ILD is characterized by upregulated interferon responses, altered CD8 T cell homeostasis, and involvement of differentiation signaling pathways of CD4 T cells. The flow cytometry analyses show that the proportions of Th17 cells and Th2 cells are increased and the proportion of Th1 cells is decreased in patients with ASS-ILD. These findings may provide foundations of novel therapeutic targets for patients with this condition.

Myositis-associated Interstitial Lung Disease: Clinical Characteristics and Factors Related to Pulmonary Function Improvement: A Latin-American Multicenter Cohort Study

BACKGROUND AND OBJECTIVES

ILD patients can be positive to highly specific autoantibodies of connective tissue diseases (CTD). Among them stand out myositis-specific and associated autoantibodies (MSA/MAA). There is limited knowledge about treatment response and prognosis of ILD patients positive to MSA/MAA (MSA/MAA-ILD). Our aim was to describe clinical, radiological and pulmonary function (PF) of MSA/MAA-ILD Latin-American patients and risk factors associated to PF at onset and long term follow up.

METHODS

Multicentric retrospective study of MSA/MAA-ILD patients evaluated between 2016 and 2018 in 3 ILD clinics in Latin America. Clinical, functional and tomographic variables were described. Variables associated with poor baseline PF and associated with functional improvement (FI) were analyzed in a multivariate logistic regression model.

RESULTS

We included 211 patients, 77.4% female, mean age 57 years old. Most frequent MSA/MAA were Ro-52 and Jo-1. Poor baseline PF was associated to ILD as initial diagnosis and NSIP/OP HRCT pattern. 121 patients were included in the follow up PF analysis: 48.8% remained stable and 33% had a significant FI. In multivariate analysis, OP pattern on HRCT was associated with FI. Systemic symptoms from the beginning and the absence of sclerodactyly showed a trend to be associated with FI.

CONCLUSIONS

Worse baseline PF could be related to the absence of extra-thoracic symptoms and "classic" antibodies in CTD (ANA), which causes delay in diagnosis and treatment. In contrast, FI could be related to the presence of extra-thoracic signs that allow timely diagnosis and therapy, and more acute and subacute forms of ILD, such as OP pattern.

Inflammatory myopathies: an update for neurologists

Idiopathic inflammatory myopathies (IIM) are a heterogenous group of treatable myopathies. Patients present mainly to the rheumatologist and neurologists, complaining of acute or subacute onset of proximal weakness. Extramuscular manifestations may occur, including involvement of the lungs, skin, and joints. Classically, the diagnosis used to be made based on the creatine kinase level increase, abnormalities in electroneuromyography and presence of inflammatory infiltrates in the muscle biopsy. Recently, the importance of autoantibodies has increased, and now they may be identified in more than half of IIM patients. The continuous clinicoseropathological improvement in IIM knowledge has changed the way we see these patients and how we classify them. In the past, only polymyositis, dermatomyositis and inclusion body myopathy were described. Currently, immune-mediated necrotizing myopathy, overlap myositis and antisynthetase syndrome have been considered the most common forms of IIM in clinical practice, increasing the spectrum of classification. Patients previously considered to have polymyositis, in fact have these other forms of seropositive IIM. In this article, we reviewed the new concepts of classification, a practical way to make the diagnosis and how to plan the treatment of patients suffering from IIM.

Performance of the 2017 EULAR/ACR classification criteria in anti-MDA5 associated idiopathic inflammatory myopathy

OBJECTIVE

To evaluate the performance of the 2017 EULAR/ACR classification criteria in a cohort of anti-MDA5 associated IIM patients.

METHODOLOGY

Consecutive adult patients with a clinical diagnosis of anti-MDA5 associated IIM from 10 hospitals in Hong Kong were recruited retrospectively. Clinical characteristics were collected by reviewing the electronic medical records. A commercial line-blot immunoassay was used to detect the myositis specific antibodies (MSA). Performance of the 2017 EULAR/ACR classification criteria was examined. Incorporation of the anti-MDA5 antibody in the EULAR/ACR criteria and the MSA-based criteria recently proposed by Casal-Dominguez et al. were also evaluated. Lastly, a new set of phenotypic-serological classification criteria specific for anti-MDA5 was proposed.

RESULTS

A hundred and twenty patients with anti-MDA5 associated IIM were recruited. The subgroups were exclusively DM (31.7%) and CADM (68.3%). Eight-six (71.7%) and 49 (40.8%) patients fulfilled the EULAR/ACR classification criteria and the Bohan/Peter criteria respectively. With the addition of Sontheimer's criteria for CADM, 76.7% the patients could be classified by the Bohan and Peter criteria. The sensitivity of the EULAR/ACR criteria could be improved to 98.3% if anti-MDA5 antibody was considered one of the criteria. The criteria by Casal-Dominguez et al. had 100% sensitivity in this cohort. Our newly proposed criteria for "anti-MDA5 syndrome" could also classify 97.5% of the patients.

CONCLUSIONS

Almost 30% of patients with clinical anti-MDA5 associated IIM could not be classified by the EULAR/ACR criteria. Modification of the existing criteria incorporating anti-MDA5 antibody or development of a new specific set of criteria for "anti-MDA5 syndrome" are suggested.

Echocardiographic Characteristics of Patients with Anti‐synthetase Syndrome

Right ventricular (RV) dysfunction and pulmonary hypertension (PH) occurs in approximately one‐third of patients with interstitial lung disease (ILD) and is associated with reduced 6‐minute walk distance (6MWD), and increased hospitalizations and mortality. Although the impact of RV dysfunction and PH has been well described in several types of ILD, data is scarce on antisynthetase syndrome. Therefore, we sought to examine the presence of RV dysfunction and PH in patients with antisynthetase syndrome and the impact on clinical outcomes. We conducted a retrospective study of patients with antisynthetase syndrome. Seventy‐five subjects were identified. Fifty‐one (68%) subjects had echocardiographic data. Patients were grouped into those with normal fractional area change (FAC) ≥ 35% and reduced FAC < 35%. Clinical, echocardiographic, and right heart catheterization data were compared between the two groups. Subjects with FAC < 35% had lower diffusion capacity of the lung for carbon monoxide (29% vs. 47%, p = 0.004), fibrotic features on computed tomography of the chest (79% vs. 33%, p = 0.005), larger RV diameter (5.4 vs. 3.9 cm, p < 0.001), higher right atrial pressures (8 vs. 5 mmHg, p = 0.02), and required supplemental oxygen more frequently (100% vs. 44%, p < 0.001) compared to those with FAC ≥ 35%. We found no difference in 6MWD and hospitalizations between the two groups. The presence of RV dysfunction in antisynthetase syndrome may identify patients at risk of poor outcomes.

Pathophysiological Mechanisms and Treatment of Dermatomyositis and Immune Mediated Necrotizing Myopathies: A Focused Review

Idiopathic inflammatory myopathies (IIM), collectively known as myositis, are a composite group of rare autoimmune diseases affecting mostly skeletal muscle, although other organs or tissues may also be involved. The main clinical feature of myositis is subacute, progressive, symmetrical muscle weakness in the proximal arms and legs, whereas subtypes of myositis may also present with extramuscular features, such as skin involvement, arthritis or interstitial lung disease (ILD). Established subgroups of IIM include dermatomyositis (DM), immune-mediated necrotizing myopathy (IMNM), anti-synthetase syndrome (ASyS), overlap myositis (OM) and inclusion body myositis (IBM). Although these subgroups have overlapping clinical features, the widespread variation in the clinical manifestations of IIM suggests different pathophysiological mechanisms. Various components of the immune system are known to be important immunopathogenic pathways in IIM, although the exact pathophysiological mechanisms causing the muscle damage remain unknown. Current treatment, which consists of glucocorticoids and other immunosuppressive or immunomodulating agents, often fails to achieve a sustained beneficial response and is associated with various adverse effects. New therapeutic targets have been identified that may improve outcomes in patients with IIM. A better understanding of the overlapping and diverging pathophysiological mechanisms of the major subgroups of myositis is needed to optimize treatment. The aim of this review is to report on recent advancements regarding DM and IMNM.

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.

Overlapping rheumatoid arthritis and antisynthetase syndrome with secondary Sjögren’s syndrome: a case report and review of the literature

Background

Overlap syndromes account for about 25% of autoimmune diseases. They are many possible combinations of known autoimmune diseases increasingly diagnosed with the identification of of a large number of autoantibodies. In this case report, we present a patient with rare overlapping rheumatoid arthritis–antisynthetase syndrome with associated secondary Sjögren’s syndrome atypically presenting without interstitial lung disease.

Case presentation

A 52-year-old Sinhalese female, a known patient with type 2 diabetes mellitus, presented with a history of symmetrical inflammatory-type polyarthritis with significant morning stiffness, proximal muscle weakness, pain, and roughening of the fingertips with associated sicca symptoms of 5 months duration. Examination revealed features of active joint inflammation, mechanic’s hand, xerostomia, and left-sided breast lump. Investigations confirmed the presence of rheumatoid arthritis with strongly positive rheumatoid factor (202 U/ml) and anti-cyclic citrullinated peptide antibody (717 U/ml). Antisynthetase syndrome was also diagnosed with borderline-positive anti-aminoacyl-tRNA antibodies but without interstitial lung disease. Sjögren’s syndrome was confirmed by the clinical history and histology and considered a secondary disorder. As her breast lump proved to be benign, no further interventions were done. She was started on sulfasalazine and methotrexate with steroid bridging therapy and achieved remission and had good control of the disease without any joint deformity or flare-up on 6-month clinic follow-up.

Discussion

Overlapping rheumatoid arthritis–antisynthetase syndrome is a very rare disease with disabling complications. Early identification of the atypical presentations of the overlap syndromes, by thorough investigations, helps physicians to prescribe proper disease-modifying antirheumatoid drugs and biological drugs. It also helps predict the prognosis of the patients before they develop complications.

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.

Treatment Outcomes of Infectious and Non-infectious Acute Exacerbation of Myositis-Related Interstitial Lung Disease

Introduction

Although respiratory infections are common causes of acute respiratory failure (ARF) in patients with myositis-interstitial lung disease (ILD), limited data are available regarding the treatment outcomes by the etiologies of acute exacerbation (AE) of myositis-related ILD (infectious vs. non-infectious). Our study aimed to investigate the treatment outcomes of AE in patients with myositis-related ILD focused on the infectious etiology.

Methods

A single center-based retrospective cohort was performed at Hanyang University Hospital between January 2000 and December 2018. A total of 36 patients with AE of myositis-related ILD were consecutively included. The exposure was the etiologies of AE in myositis-related ILD, and the outcome was in-hospital mortality. The infectious etiology was defined as confirmation of bacteria, virus, or fungus in samples obtained from the respiratory tract.

Results

Among the 36 patients, 17 were diagnosed with infectious AE. The overall in-hospital mortality rate of AE was 47.2%. Although the mortality rate in patients with infectious AE was lower (41.2%) than in those with non-infectious AE (52.6%), this difference was not statistically significant (p = 0.724). A survival analysis showed no significant difference in mortality between patients with infectious AE versus those with non-infectious AE [risk ratio = 0.78, 95% CI = 0.38–1.59].

Conclusion

Our study showed that infectious AE is an important cause of mortality in patients with myositis-related ILD, showing a similar risk of mortality as non-infectious AE.