Idiopathic inflammatory myopathies and the lung

Clinical Characteristics of Anti-Synthetase Syndrome: Analysis From the Classification Criteria for Anti-Synthetase Syndrome Project

OBJECTIVE

Anti-synthetase syndrome (ASSD) is a rare systemic autoimmune rheumatic disease (SARD) with significant heterogeneity and no shared classification criteria. We aimed to identify clinical and serological features associated with ASSD that may be suitable for inclusion in the data-driven classification criteria for ASSD.

METHODS

We used a large, international, multicenter "Classification Criteria for Anti-synthetase Syndrome" (CLASS) project database, which includes both patients with ASSD and controls with mimicking conditions, namely, SARDs and/or interstitial lung disease (ILD). The local diagnoses of ASSD and controls were confirmed by project team members. We employed univariable logistic regression and multivariable Ridge regression to evaluate clinical and serological features associated with an ASSD diagnosis in a randomly selected subset of the cohort.

RESULTS

Our analysis included 948 patients with ASSD and 1,077 controls. Joint, muscle, lung, skin, and cardiac involvement were more prevalent in patients with ASSD than in controls. Specific variables associated with ASSD included arthritis, diffuse myalgia, muscle weakness, muscle enzyme elevation, ILD, mechanic's hands, secondary pulmonary hypertension due to ILD, Raynaud phenomenon, and unexplained fever. In terms of serological variables, Jo-1 and non-Jo-1 anti-synthetase autoantibodies, antinuclear antibodies with cytoplasmic pattern, and anti-Ro52 autoantibodies were associated with ASSD. In contrast, isolated arthralgia, dysphagia, electromyography/magnetic resonance imaging/muscle biopsy findings suggestive of myopathy, inflammatory rashes, myocarditis, and pulmonary arterial hypertension did not differentiate between patients with ASSD and controls or were inversely associated with ASSD.

CONCLUSION

We identified key clinical and serological variables associated with ASSD, which will help clinicians and offer insights into the development of data-driven classification criteria for ASSD.

The role of multicriteria decision analysis in the development of candidate classification criteria for antisynthetase syndrome: analysis from the CLASS project

OBJECTIVES

To develop and evaluate the performance of multicriteria decision analysis (MCDA)-driven candidate classification criteria for antisynthetase syndrome (ASSD).

METHODS

A list of variables associated with ASSD was developed using a systematic literature review and then refined into an ASSD key domains and variables list by myositis and interstitial lung disease (ILD) experts. This list was used to create preferences surveys in which experts were presented with pairwise comparisons of clinical vignettes and asked to select the case that was more likely to represent ASSD. Experts' answers were analysed using the Potentially All Pairwise RanKings of all possible Alternatives method to determine the weights of the key variables to formulate the MCDA-based classification criteria. Clinical vignettes scored by the experts as consensus cases or controls and real-world data collected in participating centres were used to test the performance of candidate classification criteria using receiver operating characteristic curves and diagnostic accuracy metrics.

RESULTS

Positivity for antisynthetase antibodies had the highest weight for ASSD classification. The highest-ranked clinical manifestation was ILD, followed by myositis, mechanic's hands, joint involvement, inflammatory rashes, Raynaud phenomenon, fever, and pulmonary hypertension. The candidate classification criteria achieved high areas under the curve when applied to the consensus cases and controls and real-world patient data. Sensitivities, specificities, and positive and negative predictive values were >80%.

CONCLUSIONS

The MCDA-driven candidate classification criteria were consistent with published ASSD literature and yielded high accuracy and validity.

Patients with anti-PM/Scl-positive and idiopathic inflammatory myopathy resemble anti-synthetase syndrome

BACKGROUND

Anti-PM/Scl autoantibody has been associated with an overlap between polymyositis (PM) and systemic sclerosis (SSc). However, due to limited studies, the relevance of this autoantibody in patients with idiopathic inflammatory myopathies (IIMs) without SSc was analyzed.

METHODS

This single-center retrospective cohort study was conducted between 2004 and 2024. A total of 93 adult patients with IIMs (66 with dermatomyositis and 27 with PM - EULAR/ACR 2017) without SSc were included: 16 anti-PM/Scl(+) and 77 anti-PM/Scl(-). Patients with other types of IIMs, cancer-associated myositis, or overlap myositis, including SSc, as well as those with other myositis-specific and/or myositis-associated autoantibodies were excluded.

RESULTS

The median age, sex distribution, and median follow-up duration were comparable between the anti-PM/Scl(+) and anti-PM/Scl(-) groups. There were no differences in clinical and laboratory characteristics, except for a higher frequency of lung involvement, joint involvement, "mechanics' hand," "hiker's feet," and Raynaud's phenomenon, in contrast to a lower frequency of facial rash and "V"-neck sign in patients with anti-PM/Scl(+) than in those with anti-PM/Scl(-) (all P < 0.05). Furthermore, patients with anti-PM/Scl(+) exhibited a higher frequency of disease relapse (68.8% vs. 33.8%), disease activity (50.0% vs. 24.7%), and immunosuppressant use (methotrexate or azathioprine) at the last medical evaluation (all P < 0.05). Severe infection and death rates were comparable between the groups.

CONCLUSIONS

Anti-PM/Scl positivity was observed in 17.2% of the sample analyzed in the present study. Patients with this autoantibody present clinical manifestations resembling anti-synthetase syndrome, with increased disease relapse and activity rates.

Mortality Risk Prediction in Patients With Antimelanoma Differentiation-Associated, Gene 5 Antibody-Positive, Dermatomyositis-Associated Interstitial Lung Disease: Algorithm Development and Validation

BACKGROUND

Patients with antimelanoma differentiation-associated gene 5 antibody-positive dermatomyositis-associated interstitial lung disease (anti-MDA5+DM-ILD) are susceptible to rapidly progressive interstitial lung disease (RP-ILD) and have a high risk of mortality. There is an urgent need for a reliable prediction model, accessible via an easy-to-use web-based tool, to evaluate the risk of death.

OBJECTIVE

This study aimed to develop and validate a risk prediction model of 3-month mortality using machine learning (ML) in a large multicenter cohort of patients with anti-MDA5+DM-ILD in China.

METHODS

In total, 609 consecutive patients with anti-MDA5+DM-ILD were retrospectively enrolled from 6 hospitals across China. Patient demographics and laboratory and clinical parameters were collected on admission. The primary endpoint was 3-month mortality due to all causes. Six ML algorithms (Extreme Gradient Boosting [XGBoost], logistic regression (LR), Light Gradient Boosting Machine [LightGBM], random forest [RF], support vector machine [SVM], and k-nearest neighbor [KNN]) were applied to construct and evaluate the model.

RESULTS

After applying inclusion and exclusion criteria, 509 (83.6%) of the 609 patients were included in our study, divided into a training cohort (n=203, 39.9%), an internal validation cohort (n=51, 10%), and 2 external validation cohorts (n=92, 18.1%, and n=163, 32%). ML identified 8 important variables as critical for model construction: RP-ILD, erythrocyte sedimentation rate (ESR), serum albumin (ALB) level, age, C-reactive protein (CRP) level, aspartate aminotransferase (AST) level, lactate dehydrogenase (LDH) level, and the neutrophil-to-lymphocyte ratio (NLR). LR was chosen as the best algorithm for model construction, and the model demonstrated excellent performance, with an area under the receiver operating characteristic (ROC) curve (AUC) of 0.866, a sensitivity of 84.8%, and a specificity of 84.4% on the validation data set and an AUC of 0.90, a sensitivity of 85.0%, and a specificity of 83.9% on the training data set. Calibration curves and decision curve analysis (DCA) confirmed the model's accuracy and clinical applicability. Moreover, the model showed strong predictive performance in the external validation cohorts (cohort 1: AUC=0.836, 95% CI 0.754-0.916; cohort 2: AUC=0.915, 95% CI 0.871-0.959), indicating good generalizability. This model was integrated into a web-based tool to predict the 3-month mortality for patients with anti-MDA5+DM-ILD.

CONCLUSIONS

We successfully developed a robust clinical prediction model and an accompanying web tool to estimate the 3-month mortality risk for patients with anti-MDA5+DM-ILD.

The Role of Nailfold Videocapillaroscopy in the Diagnosis and Monitoring of Interstitial Lung Disease Associated with Rheumatic Autoimmune Diseases

Interstitial lung disease (ILD) is a severe complication of certain connective tissue diseases (CTDs) such as systemic sclerosis (SSc), mixed connective tissue disease (MCTD), idiopathic inflammatory myopathies (IIM), rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE), and it is associated with nailfold videocapillaroscopy (NVC) changes and increased morbidity and mortality rates. Early diagnosis is crucial in order to prevent the progression of ILD, prevent respiratory failure and enhance the patient's overall quality of life. The most common paraclinical investigations are high-resolution computed tomography (HRCT) and functional respiratory tests such as forced vital capacity (FVC) and the diffusing capacity of the lungs for carbon monoxide (DLCO). The most frequent CTD associated with both ILD and NVC changes is systemic sclerosis. The "late" scleroderma pattern was the most common abnormality identified in NVC results in SSc patients. Other autoimmune diseases were also correlated with ILD and NVC changes, especially when the Raynaud phenomenon was present. Low capillary density was associated with the presence and severity of ILD and a reduction in FVC and DLCO. NVC can also differentiate the capillaroscopic changes in some particular types of ILD, such as the usual interstitial pneumonia (UIP) pattern from the non-specific interstitial pneumonia (NSIP) pattern. Nevertheless, further extensive research is necessary in order to establish the diagnostic value of NVC in CTD-ILD in clinical practice.

Prevalence and risk surveillance of anti-mitochondrial antibody-positive myositis: Outcomes of a nationwide survey

BACKGROUND

Anti-mitochondrial antibody (AMA)-positive myositis is a chronic disease characterized by skeletal muscle atrophy and is associated with cardiac complications and restrictive ventilatory impairment. This study aimed to determine the prevalence, rate of organ complications, and prognostic risk factors of AMA-positive myositis.

METHODS

We conducted a cross-sectional study using a nationwide questionnaire from 2011 to 2021, enrolling participants from neurology departments at 811 facilities certified by the Japanese Society of Neurology.

RESULTS

A total of 380 patients were identified, with a prevalence rate of 0.3 per 100,000 persons. The frequencies of cardiac complications and restrictive ventilatory impairment were 53 and 33 %, respectively; whereas, those of cardiac device and respirator introduction were 32 and 22 %, respectively. The frequencies of recurrence, subacute exacerbation, no muscle strength improvement, cardiac device introduction, respirator introduction, and death were 29, 25, 54, 32, 22, and 12 %, respectively. According to univariate analysis, abnormal echocardiograms (odds ratio [OR], 5.43), restrictive ventilatory impairment (OR, 3.70), and inflammatory changes revealed by muscle biopsy (OR, 0.34) were associated with subacute exacerbations, whereas abnormal echocardiograms (OR, 8.00) and durations from onset to admission and diagnosis (OR, 2.99) were associated with cardiac device introduction. Multivariable analysis showed that restrictive ventilatory impairment was associated with recurrence (adjusted OR, 3.01), adjusted for the duration from onset to admission and diagnosis, and with subacute exacerbations (adjusted OR, 3.86), adjusted for abnormal echocardiograms and inflammatory changes.

CONCLUSIONS

AMA-positive myositis is characterized by severe and urgent organ complications, and anticipatory management is critical for management of this disease.

Efficacy and safety of a step-down regimen of low dosage of glucocorticoids combined with early administration of synthetic or biologic immunosuppressants in anti-synthetase syndrome: A pilot study

INTRODUCTION

Anti-synthetase syndrome (ASS) is a rare autoimmune disease characterized by the presence of anti-aminoacyl-transfer-RNA synthetase antibodies (ARS) and the involvement of muscles, skin, joints, and lungs. Despite increasing interest and evidence, optimal clinical management remains unclear due to a lack of randomized control trials. This study aims to evaluate the efficacy and safety of a treatment regimen involving early co-administration of glucocorticoids and immunosuppressants, with rapid prednisone tapering.

MATERIALS AND METHODS

We prospectively enrolled patients referred to our multidisciplinary "Myositis Clinic" with a diagnosis of ASS. Clinical, serological, instrumental and medications data were collected at baseline and at 6 and 12 months follow-up. According to treatment protocol, patients were treated with traditional synthetic immunosuppressants or rituximab (RTX) depending on clinical manifestations. Prednisone (PDN) was gradually tapered and eventually discontinued within 6 or 12 months.

RESULTS

A total of twenty-seven subjects were enrolled: arthritis, myositis and ILD were assessed in 9, 16 and 18 patients, respectively, and all of them had an active disease. RTX was administered after methotrexate (MTX) in 4 cases of refractory joint involvement and co-administration of a second immunosuppressant was necessary in 2 patients. When muscle involvement was present, first-line therapy was MTX, followed by mycophenolate mofetil (MMF) or RTX, which allowed to achieve low disease activity or remission, respectively. Eight ILD-patients were treated with MMF and switched to RTX in 5 cases of inefficacy, but all patients were in clinical remission at the end of follow-up. At 12 months, 12 patients discontinued PDN.

CONCLUSIONS

This study is the first to prospectively report on the efficacy and safety of a stepwise, steroid-sparing treatment ASS encompassing various domains. MTX, as well as other synthetic immunosuppressants, showed limited efficacy in ASS-related arthritis, while RTX emerged as a promising option. This study recommends early RTX use in case of arthritis, suggesting it as a pivotal treatment for ILD too, and raises questions regarding maintenance therapy and treatment-free remission.

One-year survival benefit of plasma exchange in idiopathic inflammatory myositis patients with progressive interstitial lung disease-a systemic review and meta-analysis

OBJECTIVES

This study aimed to systematically evaluate the efficacy of plasma exchange (PLEX) in patients with idiopathic inflammatory myositis (IIM) complicated by interstitial lung disease (ILD).

METHOD

We conducted a comprehensive literature search in Medline and EMBASE from their inception to August 2023, focusing on randomized controlled trials, cohort studies, and case-control studies involving IIM patients with ILD treated with PLEX compared to those treated with standard therapies. The primary outcome was the one-year survival rate. All the statistical analyses were performed using RevMan version 4.12.0.

RESULTS

Out of 438 retrieved studies, 16 were selected for full-text review. Six cohort studies involving 148 patients with anti-melanoma differentiation-associated gene 5 (MDA5)-positive dermatomyositis or antisynthetase syndrome-related dermatomyositis with rapidly progressive ILD refractory to standard treatments (including glucocorticoids, immunosuppressive agents, or intravenous immunoglobulin) met the inclusion criteria. Patients receiving PLEX in addition to other therapies demonstrated a greater one-year survival rate (relative risk [RR] 1.59, 95 % CI 0.96-2.65, I2 52 %) than did patients in the non-PLEX group. Significance was reached in a sensitivity analysis after excluding one outlier (RR 1.71, 95 % confidence intervals [CI] 1.30-2.25; I2 0 %). Additionally, there was a trend suggesting that PLEX improved lung function, radiographic outcomes, and key serum biomarkers, such as Krebs von den Lungen-6 and ferritin. Funnel plot asymmetry suggested publication bias due to the lack of reporting of negative trials. All studies had a low risk of bias.

CONCLUSIONS

As an adjunctive therapy, PLEX improved one-year survival in IIM patients with rapidly progressive ILD who were unresponsive to standard treatments.

Short-term efficiency of plasma exchange in combination with immunosuppressants and/or biologics in the treatment of idiopathic inflammatory myopathy with rapidly progressive interstitial lung disease: a systematic review and meta-analysis

OBJECTIVE

Rapidly progressive interstitial lung disease (RP-ILD) is a frequent and serious manifestation of idiopathic inflammatory myopathy (IIM) associated with poor outcomes. Plasma exchange (PE) can quickly remove pathogenic substances from the blood. Therefore, PE may be efficacious in IIM patients who have elevated levels of autoantibodies, cytokines and chemokines, fighting for time for immunosuppressive therapy. However, the value of adding PE to immunosuppressants remains unclear. The purpose of this study was to determine the short-term outcomes, including the survival rate at 6 months and change of the laboratory data, of PE in combination with immunosuppressants and/or biologics in the treatment of IIM-RP-ILD.

METHODS

We searched PubMed, Embase and Cochrane Library to find reports of interest published from inception to March 4, 2024. STATA 15.1 was used for data analysis. A fixed or random-effects model with inverse-variance weighting was used to estimate the pooled risk ratio (RR) and 95% confidence interval (CI).

RESULTS

Two hundred and thirty studies were identified. Eleven studies, including five retrospective cohort studies, four case-control studies and two case series, were included. PE was performed on 114 patients. The survival rate at 6 months was 80% (95%CI = 64%-92%), with moderate heterogeneity (I2=63.45%, p < 0.05). Moreover, the 6-month survival rate was significantly better in the PE group than in the non-PE group (RR, 1.34; 95% CI = 1.05-1.71, I2=30.7%; p = 0.194). ILD-related serum markers, including ferritin, KL-6 and anti-MDA-5 antibody titres, were significantly suppressed by a series of PE treatments (p < 0.05).

CONCLUSION

The application of PE therapy plus treatment with corticosteroids, immunosuppressants and/or biologics was effective for patients with IIM-RP-ILD. PE may have additional supportive effect in intractable disease.

Characteristics of Patients with Adult-Onset Dermatomyositis at 2 Tertiary Care Centres in Ontario, Canada

Dermatomyositis (DM) is an idiopathic inflammatory myopathy characterized by progressive muscle weakness and distinctive cutaneous findings. The exact incidence and prevalence of DM in the general population is largely unknown, and data on demographic and clinical features in patients in Canada are lacking. This study aimed to comprehensively evaluate the patients with DM in Southwestern Ontario, Canada. A retrospective chart review was conducted for patients with adult-onset DM at 2 tertiary care centres in Ontario, Canada, over a 13 year period. One hundred fourteen patients were included. The mean age was 59, and 80% of patients were female. Skin and muscle involvement coincided in 63% of patients, while skin predated muscle involvement in 11%. Most common characteristic skin manifestations included Gottron's papules (69%), Heliotrope sign (66%), V sign (61%), and Shawl sign (56%). Among the 114 patients, 88 (77%) were myopathic while 26/114 (23%) were clinically amyopathic dermatomyositis. In the myopathic type, upper extremity weakness, lower extremity weakness, and dysphagia were present in 87%, 81%, and 29% of patients, respectively. Elevated creatine kinase, C-reactive protein, lactate dehydrogenase, and erythrocyte sedimentation rate were found in 66%, 35%, 33%, and 32%, respectively. Lung disease was reported in 39%, particularly interstitial lung disease. Other associated features included malignancy, cardiovascular disease, and less commonly gastrointestinal disease. DM is a multifaceted autoimmune disease with distinct cutaneous and muscular findings. Our study results align with the growing body of evidence supporting DM as a complex systemic disease with the potential involvement of other organs such as the pulmonary, cardiovascular, and gastrointestinal systems.

Myositis-Associated Interstitial Lung Disease: The Experience of a Tertiary Center

Background: Interstitial lung disease (ILD) is a common extra-muscular manifestation of idiopathic inflammatory myopathies (IIMs), often associated with a poorer prognosis and increased mortality risk. Methods: This retrospective study aimed to characterize lung involvement and treatment response in an IIM cohort at a Portuguese tertiary center, followed between June 2016 and March 2024. We analyzed data from high-resolution computed tomography (HRCT) scans and pulmonary function tests (PFTs) to assess associations with autoantibody profiles and treatment regimens. Results: A total of 198 patients were included, with 69 (34.8%) exhibiting ILD. Antisynthetase syndrome (ASyS) and dermatomyositis were the most common diagnoses among IIM-ILD patients, with ASyS being significantly more frequent in this group than in non-ILD patients (p < 0.001). Anti-Jo1 and anti-MDA-5 antibodies were more frequent in ILD patients (p < 0.001 and p = 0.021), while anti-Mi2 antibodies were less common (p = 0.002). Non-specific interstitial pneumonia (NSIP) was the most common radiological pattern (69.5%). IIM-ILD patients presented with significantly lower forced vital capacity (FVC) and diffusing capacity of the lung for carbon monoxide (DLCO) compared to non-ILD patients (p < 0.001 for all values). Longitudinal analysis showed improved DLCO (p = 0.022) and stable or improved FVC (p = 0.097), especially with intravenous immunoglobulin (IVIg) and azathioprine (AZA). Combination therapies including IVIg with mycophenolate mofetil (MMF) or rituximab (RTX) also improved DLCO and FVC. Most ILD patients (89.6%) had stable HRCT patterns over time. Conclusions: Our findings highlight the potential for stabilizing or even improving lung function in IIM-ILD with appropriate immunosuppressive therapy, particularly with regimens incorporating IVIg and AZA, and combination therapies.

Lung imaging patterns in connective tissue disease-associated interstitial lung disease impact prognosis and immunosuppression response

OBJECTIVES

Interstitial lung disease (ILD) in CTDs has highly variable morphology. We aimed to identify imaging features and their impact on ILD progression, mortality, and immunosuppression response.

METHODS

Patients with CTD-ILD had high-resolution chest CT (HRCT) reviewed by expert radiologists blinded to clinical data for overall imaging pattern [usual interstitial pneumonia (UIP); non-specific interstitial pneumonia (NSIP); organizing pneumonia (OP); fibrotic hypersensitivity pneumonitis (fHP); and other]. Transplant-free survival and change in percent-predicted forced vital capacity (FVC) were compared using Cox and linear mixed-effects models adjusted for age, sex, smoking, and baseline FVC. FVC decline after immunosuppression was compared with pre-treatment.

RESULTS

Among 645 CTD-ILD patients, the most frequent CTDs were SSc (n = 215), RA (n = 127), and inflammatory myopathies (n = 100). NSIP was the most common pattern (54%), followed by UIP (20%), fHP (9%), and OP (5%). Compared with the case for patients with UIP, FVC decline was slower in patients with NSIP (by 1.1%/year, 95% CI 0.2, 1.9) or OP (by 3.5%/year, 95% CI 2.0, 4.9), and mortality was lower in patients with NSIP [hazard ratio (HR) 0.65, 95% CI 0.45, 0.93] or OP (HR 0.18, 95% CI 0.05, 0.57), but higher in fHP (HR 1.58, 95% CI 1.01, 2.40). The extent of fibrosis also predicted FVC decline and mortality. After immunosuppression, FVC decline was slower compared with pre-treatment in NSIP (by 2.1%/year, 95% CI 1.4, 2.8), with no change for UIP or fHP.

CONCLUSION

Multiple radiologic patterns are possible in CTD-ILD, including a fHP pattern. NSIP and OP were associated with better outcomes and response to immunosuppression, while fHP had worse survival compared with UIP.

Case report: Antisynthetase syndrome with positive anti-PL7/SSA/RO52 antibodies

Background

Antisynthetase syndrome (ASS) is a rare autoimmune disease characterized by the immune system attacking specific synthetase in the body. Due to the difficulty in clinical diagnosis, there is still a lack of effective treatment.

Methods

We report a case of a 50-year-old man who presented with progressive, symmetric limb weakness, starting from the lower limbs and gradually affecting the upper limbs. He was admitted to the intensive care unit (ICU) for treatment due to recurrent fever and coma. When he was admitted to the ICU, his limbs were almost unable to move, and the levels of creatine phosphokinase and muscle glycogen were significantly elevated (2449 u/l and 1857 ng/ml). The electromyogram showed myogenic injury, and the anti-PL7 antibody, anti-SSA antibody, and anti-Ro52 antibody were positive. Pathological biopsy of the left biceps brachii showed striated muscle necrosis and macrophage infiltration. He was finally diagnosed with ASS and received treatment with methylprednisolone (subsequently changed to prednisone) and traditional Chinese medicine (Buzhongyiqi Decoction and Shenlingbaizhu powder).

Results

After receiving 2 weeks of glucocorticoid and traditional Chinese medicine treatment, his muscle strength had basically recovered, reaching grade 5 in his limb muscles strength. During the 3-month follow-up period, his activity tolerance continued to improve.

Conclusion

We present a case of severe anti-PL7 positive ASS with positive anti-SSA/Ro52 antibody. The disease was relieved by glucocorticoid and traditional Chinese medicine treatment. This provides an effective approach for managing ASS.

High Prevalence of Myositis-Specific and Associated Antibodies in Patients with Pulmonary Hypertension

Pulmonary hypertension (PH) is a serious condition linked to immune-system dysfunction. Myositis-specific/associated antibodies (MSAs/MAAs) play a role in idiopathic inflammatory myopathy (IIM) and interstitial lung disease (ILD), but their significance in PH remains unclear. We believe the presence of these antibodies may be underestimated. This study analyzed adult PH patients without pre-existing IIM for MSA/MAA prevalence using a line-blot assay. We compared PH patients with and without ILD signs to a cohort clinically suspected of IIM/ILD (n = 558). Our PH cohort (n = 121) showed a significantly higher prevalence of overall weak positive MSAs/MAAs and positive overlap syndrome-associated MAAs than the suspected IIM/ILD group (p < 0.001). Notably, MSAs/MAAs were found in PH patients both with and without ILD, though more prevalent in those with ILD. Anti-synthetase and anti-overlap syndrome antibodies were the most common. Our study is the first to systematically show a high MSA/MAA prevalence in PH without IIM presentation. This highlights the need to consider PH when diagnosing MSA/MAA-associated conditions. We recommend MSA/MAA screening for newly diagnosed PH, especially in those with ILD, for early detection and potential immunomodulatory treatment. Further research should explore the link between MSAs/MAAs and PH, and the value of monitoring patients with weak MSA/MAA positivity over time.

Rapid Progression of Acute Interstitial Pneumonia in a Patient with Low MDA-5 Antibody Titer

BACKGROUND Melanoma differentiation associated gene-5 antibody (MDA-5 Ab) is one of the diagnostic autoantibodies that appears in idiopathic inflammatory myopathies (IIMs). Unlike when other autoantibodies are positive, when this antibody is positive, there is less characteristic muscle involvement. However, this MDA-5 Ab-positive myopathy presents extremely rapid progression of interstitial lung disease, resulting in a high mortality rate. Previous studies reported that the prognosis of this lung disease will be determined by the titer and suggest that low titers of MDA-5 antibody can indicate a good prognosis in associated interstitial lung disease. CASE REPORT Our case describes a 55-year-old woman who presented with acute respiratory symptoms and dyspnea. After hospitalization, symptoms and chest imaging worsened rapidly, and the radiology image of lung disease featured interstitial changes not seen in typical infections. We treated the patient with a high-flow oxygen nasal cannula, empirical antibiotics, and a systemic steroid. While treatment for a disease of unknown cause was continued, low titer of MDA-5 antibody was identified. CONCLUSIONS This case suggests 2 points to consider about non-infectious interstitial changes with acute respiratory distress syndrome. First, when treating rapidly progressing interstitial pneumonia of an unknown cause, it is recommended to consider lung involvement of MDA-5 Ab dermatomyositis. Second, a low titer of MDA-5 Ab can be associated with better prognosis in this MDA-5 Ab dermatomyositis-related lung disease.

Clinical profiles and treatment outcomes of outpatients with interstitial lung disease and mechanic's hands: A retrospective and observational cohort

Idiopathic inflammatory myopathies, especially antisynthetase syndrome, often appear outside of the muscles as interstitial lung disease (ILD). Another typical finding is the presence of mechanic's hands. The aim of the present study was to describe the clinical, functional, tomographic, and serological data of patients with ILD and mechanic's hands and their response to treatment and survival rates. This is a retrospective study of ILD with concurrent myopathy. Among the 119 patients initially selected, 51 had mechanic's hands. All the patients were screened for anti-Jo-1 antibodies. An expanded panel of myopathy autoantibodies was also performed in 27 individuals. Of the 51 patients, 35 had 1 or more antibodies. The most common were anti-Jo-1, anti-PL-7, and anti-PL-12, while of the associated antibodies, anti-Ro52 was present in 70% of the 27 tested individuals. A significant response to treatment was characterized by an increase in predicted forced vital capacity (FVC) of at least 5% in the last evaluation done after 6 to 24 months of treatment. A decrease in predicted FVC of at least 5%, the need for oxygen therapy, or death were all considered treatment failures. All patients were treated with corticosteroids, and 71% with mycophenolate. After 24 months, 18 patients had an increase in FVC, 11 had a decrease, and 22 remained stable. After a median follow-up of 58 months, 48 patients remained alive and three died. Patients with honeycombing on high-resolution chest tomography (log-rank = 34.65; P < .001) and a decrease in FVC ≥5% (log-rank = 18.28, P < .001) had a poorer survival rate. Patients with ILD and mechanic's hands respond well to immunosuppressive treatment.

Undercover lung damage in pediatrics - a hot spot in morbidity caused by collagenoses

Connective tissue represents the support matrix and the connection between tissues and organs. In its composition, collagen, the major structural protein, is the main component of the skin, bones, tendons and ligaments. Especially at the pediatric age, its damage in the context of pathologies such as systemic lupus erythematosus, scleroderma or dermatomyositis can have a significant negative impact on the development and optimal functioning of the body. The consequences can extend to various structures (e.g., joints, skin, eyes, lungs, heart, kidneys). Of these, we retain and reveal later in our manuscript, mainly the respiratory involvement. Manifested in various forms that can damage the chest wall, pleura, interstitium or vascularization, lung damage in pediatric systemic inflammatory diseases is underdeveloped in the literature compared to that described in adults. Under the threat of severe evolution, sometimes rapidly progressive and leading to death, it is necessary to increase the popularization of information aimed at physiopathological triggering and maintenance mechanisms, diagnostic means, and therapeutic directions among medical specialists. In addition, we emphasize the need for interdisciplinary collaboration, especially between pediatricians, rheumatologists, infectious disease specialists, pulmonologists, and immunologists. Through our narrative review we aimed to bring up to date, in a concise and easy to assimilate, general principles regarding the pulmonary impact of collagenoses using the most recent articles published in international libraries, duplicated by previous articles, of reference for the targeted pathologies.

Pulmonary Hypertension in Connective Tissue Diseases Other than Systemic Sclerosis

Pulmonary hypertension (PH) is a known complication of certain connective tissue diseases (CTDs), with systemic sclerosis (SSc) being the most common in the Western world. However, PH in association with non-SSc CTD such as systemic lupus erythematous, mixed connective tissue disease, and primary Sjögren's syndrome constitutes a distinct subset of patients with inherently different epidemiologic profiles, pathophysiologic mechanisms, clinical features, therapeutic options, and prognostic implications. The purpose of this review is to inform a practical approach for clinicians evaluating patients with non-SSc CTD-associated PH.The development of PH in these patients involves a complex interplay between genetic factors, immune-mediated mechanisms, and endothelial cell dysfunction. Furthermore, the broad spectrum of CTD manifestations can contribute to the development of PH through various pathophysiologic mechanisms, including intrinsic pulmonary arteriolar vasculopathy (pulmonary arterial hypertension, Group 1 PH), left-heart disease (Group 2), chronic lung disease (Group 3), chronic pulmonary artery obstruction (Group 4), and unclear and/or multifactorial mechanisms (Group 5). The importance of diagnosing PH early in symptomatic patients with non-SSc CTD is highlighted, with a review of the relevant biomarkers, imaging, and diagnostic procedures required to establish a diagnosis.Therapeutic strategies for non-SSc PH associated with CTD are explored with an in-depth review of the medical, interventional, and surgical options available to these patients, emphasizing the CTD-specific considerations that guide treatment and aid in prognosis. By identifying gaps in the current literature, we offer insights into future research priorities that may prove valuable for patients with PH associated with non-SSc CTD.

Pleural Diseases in Connective Tissue Diseases

Connective tissue diseases (CTD) are heterogeneous, immune-mediated inflammatory disorders often presenting with multiorgan involvement. With the advent of high-resolution computed tomography, CTD-related pleuritis-pleural thickening and effusion-is now increasingly recognized early in the disease trajectory. The natural history of CTD-related pleural effusions varies from spontaneous resolution to progressive fibrothorax with ventilatory impairment. Treatment of the underlying CTD is necessary to manage the pleural disease. Depending on the degree of symptom burden and physiological insult, specific treatment of pleural disease can include monitoring, repeated aspirations, systemic anti-inflammatory medication, and surgical decortication.

FAPi PET/CT for assessment and visualisation of active myositis-related interstitial lung disease: a prospective observational pilot study

Background

Interstitial lung disease (ILD) is a common manifestation of idiopathic inflammatory myopathies (IIM) and a substantial contributor to hospitalisation, increased morbidity, and mortality. In-vivo evidence of ongoing tissue remodelling in IIM-ILD is scarce. We aimed to evaluate fibroblast activation in lungs of IIM-patients and control individuals using ⁶⁸Ga-labelled inhibitor of Fibroblast-Activation-Protein (FAPi) based positronic emission tomography and computed tomography imaging (PET/CT).

Methods

In this prospective observational pilot study, consecutive patients with IIM and participants without rheumatic conditions or ILD serving as a control group were recruited at the Medical University of Vienna, Austria, and underwent FAPi PET/CT imaging. Standard-of-care procedures including clinical examination, assessment of severity of dyspnoea, high-resolution computed tomography (HR-CT), and pulmonary function testing (PFT) were performed on all patients with IIM at baseline and for patients with IIM-ILD at follow-up of 12 months. Baseline pulmonary FAPi-uptake was assessed by the maximum (SUVmax) and mean (SUVmean) standardized uptake values (SUV) over the whole lung (wl). SUV was corrected for blood pool background activity and target-to-background ratios (TBR) were calculated. We compared pulmonary FAPi-uptake between patients with IIM-ILD and those without ILD, as well as controls, and correlated baseline FAP-uptake with standard diagnostic tools such as HR-CT and PFT. For predictive implications, we investigated whether patients with IIM and progressive ILD exhibited higher baseline FAPi-uptake compared to those with stable ILD. Metrics are reported as mean with standard deviation (±SD).

Findings

Between November 16, 2021 and October 10, 2022, a total of 32 patients were enrolled in the study. Three participants from the control group were excluded due to cardiopulmonary disease. In individuals with IIM-ILD (n = 14), wlTBRmax and wlTBRmean were significantly increased as compared with both non-ILD-IIM patients (n = 5) and the control group (n = 16): wlTBRmax: 2.06 ± 1.04 vs. 1.04 ± 0.22 (p = 0.019) and 1.08 ± 0.19 (p = 0.0012) and wlTBRmean: 0.45 ± 0.19 vs. 0.26 ± 0.06 (p = 0.025) and 0.27 ± 0.07 (p = 0.0024). Similar values were observed in wlTBRmax or wlTBRmean between non-ILD IIM patients and the control group. Patients with progressive ILD displayed significantly enhanced wlTBRmax and wlTBRmean values at baseline compared to patients with stable ILD: wlTBRmax: 1.30 ± 0.31 vs. 2.63 ± 1.04 (p = 0.0084) and wlTBRmean: 0.32 ± 0.08 vs. 0.55 ± 0.19 (p = 0.021). Strong correlations were found between FAPi-uptake and disease extent on HR-CT (wlTBRmax: R = 0.42, p = 0.07; wlTBRmean: R = 0.56, p = 0.013) and severity of respiratory symptoms determined by the New York Heart Association (NYHA) classification tool (wlTBRmax: R = 0.52, p = 0.022; wlTBRmean: R = 0.59, p = 0.0073). Further, pulmonary FAPi-uptake showed inverse correlation with forced vital capacity (FVC) (wlTBRmax: R = -0.56, p = 0.012; wlTBRmean: R = -0.64, p = 0.0033) and diffusing capacity of the lungs for carbon monoxide (DLCO) (wlTBRmax: R = -0.52, p = 0.028; wlTBRmean: R = -0.68, p = 0.0017).

Interpretation

Our study demonstrates higher fibroblast activation in patients with IIM-ILD compared to non-ILD patients and controls. Intensity of pulmonary FAPi accumulation was associated with progression of ILD. Considering that this study was carried out on a small population, FAPi PET/CT may serve as a useful non-invasive tool for risk stratification of lung disease in IIM.

Funding

The Austrian Research Fund.

Review of Pulmonary Manifestations in Antisynthetase Syndrome

Antisynthetase syndrome (ASyS) is now a widely recognized entity within the spectrum of idiopathic inflammatory myopathies. Initially described in patients with a triad of myositis, arthritis, and interstitial lung disease (ILD), its presentation can be diverse. Additional common symptoms experienced by patients with ASyS include Raynaud's phenomenon, mechanic's hand, and fever. Although there is a significant overlap with polymyositis and dermatomyositis, the key distinction lies in the presence of antisynthetase antibodies (ASAs). Up to 10 ASAs have been identified to correlate with a presentation of ASyS, each having manifestations that may slightly differ from others. Despite the proposal of three classification criteria to aid diagnosis, the heterogeneous nature of patient presentations poses challenges. ILD confers a significant burden in patients with ASyS, sometimes manifesting in isolation. Notably, ILD is also often the initial presentation of ASyS, requiring pulmonologists to remain vigilant for an accurate diagnosis. This article will comprehensively review the various aspects of ASyS, including disease presentation, diagnosis, management, and clinical course, with a primary focus on its pulmonary manifestations.

Prognostic Role of Interferon-λ3 in Anti-Melanoma Differentiation-Associated Gene 5-Positive Dermatomyositis-Associated Interstitial Lung Disease

OBJECTIVE

Interferon-λ3 (IFNλ3) is a cytokine with antiviral functions on barrier surfaces, and it is associated with disease activity in autoimmune diseases. This study assessed the clinical significance of serum IFNλ3 levels in polymyositis/dermatomyositis (PM/DM)-associated interstitial lung disease (ILD).

METHODS

We measured serum IFNλ3 levels in 221 patients with PM/DM-ILD (155 in the derivation cohort, 66 in the validation cohort) and 38 controls. We evaluated factors associated with mortality risk among 79 patients with anti-melanoma differentiation-associated gene 5 (MDA5) antibody-positive DM-ILD.

RESULTS

Serum IFNλ3 levels at diagnosis were significantly higher in patients with PM/DM-ILD than in healthy controls. Remarkably, serum IFNλ3 levels were specifically increased in patients with anti-MDA5 antibody-positive DM-ILD in both the derivation and validation cohorts. In anti-MDA5 antibody-positive DM-ILD, patients with high IFNλ3 levels (>120 pg/mL) had significantly lower survival rates than those with low IFNλ3 levels (≤120 pg/mL). A multivariate analysis revealed that high IFNλ3 levels, as well as old age and low Pao2, were significantly associated with poor prognoses in patients with anti-MDA5 antibody-positive DM-ILD. In a classification analysis of patients with anti-MDA5 antibody-positive DM-ILD based on age, IFNλ3 level, and Pao2, patients with old age (>53 years), high IFNλ3 levels (>120 pg/mL), and low Pao2 (<75 mm Hg) had the worst survival. In lung pathologic analyses, IFNλ3-positive staining was observed in macrophages, airway epithelial cells, the pleural region, and intrapulmonary veins in patients with anti-MDA5 antibody-positive DM-ILD.

CONCLUSION

Serum IFNλ3 is a promising biomarker for identifying patients at high risk of poor outcomes in anti-MDA5 antibody-positive DM-ILD.

Pretreatment mortality risk prediction model in patients with polymyositis/dermatomyositis-associated interstitial lung disease

OBJECTIVES

Risk prediction for patients with polymyositis/dermatomyositis-associated interstitial lung disease (PM/DM-ILD) is challenging due to heterogeneity in the disease course. We aimed to develop a mortality risk prediction model for PM/DM-ILD.

METHODS

This prognostic study analysed patients with PM/DM-ILD admitted to Nanjing Drum Hospital from 2016 to 2021. The primary outcome was mortality within 1 year. We used a least absolute shrinkage and selection operator (LASSO) logistic regression model to identify predictive laboratory indicators. These indicators were used to create a laboratory risk score, and we developed a mortality risk prediction model by incorporating clinical factors. The evaluation of model performance encompassed discrimination, calibration, clinical utility and practical application for risk prediction and prognosis.

RESULTS

Overall, 418 patients with PM/DM-ILD were enrolled and randomly divided into development (n=282) and validation (n=136) cohorts. LASSO logistic regression identified four optimal features in the development cohort, forming a laboratory risk score: C reactive protein, lactate dehydrogenase, CD3+CD4+ T cell counts and PO2/FiO2. The final prediction model integrated age, arthralgia, anti-melanoma differentiation-associated gene 5 antibody status, high-resolution CT pattern and the laboratory risk score. The prediction model exhibited robust discrimination (area under the receiver operating characteristic: 0.869, 95% CI 0.811 to 0.910), excellent calibration and valuable clinical utility. Patients were categorised into three risk groups with distinct mortality rates. The internal validation, sensitivity analyses and comparative assessments against previous models further confirmed the robustness of the prediction model.

CONCLUSIONS

We developed and validated an evidence-based mortality risk prediction model with simple, readily accessible clinical variables in patients with PM/DM-ILD, which may inform clinical decision-making.

Radiological and histopathological features and treatment response by subtypes of interstitial pneumonia with autoimmune features: A prospective, multicentre cohort study

BACKGROUND

Patients with idiopathic interstitial pneumonia (IIP) have a favourable prognosis when they have interstitial pneumonia with autoimmune features (IPAF). However, precise IPAF-related findings from high-resolution computed tomography (HRCT) and lung histopathological specimens and the treatment response have not been fully determined. Therefore, this study was conducted to evaluate the relationship between findings on HRCT or lung histopathological specimens and the progression of interstitial pneumonia in patients with IPAF.

METHODS

This multicentre cohort study prospectively enrolled consecutive patients with IIP. At the diagnosis of IIP, we systematically evaluated 74 features suggestive of connective tissue diseases and followed them up. HRCT, lung specimens, serum antibodies, and the clinical course were also evaluated.

RESULTS

Among 222 patients with IIP, 26 (11.7%) fulfilled the IPAF criteria. During a median observation period of 36 months, patients with IPAF showed better survival than those without IPAF (p = 0.034). While histopathological findings were not related to IPAF, nonspecific interstitial pneumonia (NSIP) with organizing pneumonia (OP) overlap was the most prevalent HRCT pattern (p < 0.001) and the consolidation opacity was the most common radiological finding in IPAF (p = 0.017). Furthermore, in patients with IPAF, the diagnosis of COP or NSIP with OP overlap was associated with a higher increase in %FVC in 1 year than in those with idiopathic pulmonary fibrosis, NSIP, or unclassifiable IIP (p = 0.002).

CONCLUSIONS

This study shows the presence of consolidation opacity on HRCT and the diagnosis of COP or NSIP with OP overlap are associated with IPAF and its favourable treatment response in patients with IPAF.

Microarray analysis of microrna expression in peripheral blood mononuclear cells of patients with polymyositis and dermatomyositis

Background and Objectives

MicroRNAs (miRNAs) represent a new class of biomarkers in the context of connective tissue disorders. The miRNA expression profiles in peripheral blood mononuclear cells (PBMCs) of patients with polymyositis (PM) and dermatomyositis (DM) have not been fully elucidated. The objective is to investigate miRNAs expression profile in PBMCs of patients with PM/DM.

Methods

Microarray technology was used to identify differentially expressed miRNAs in PBMCs obtained from 6 untreated PM/DM patients and 3 healthy controls (HCs). TaqMan-based stem-loop real-time PCR detection was used for validation in a cohort of 34 PM/DM patients and 20 HCs.

Results

Microarray analysis revealed 38 differentially expressed miRNAs (24 up-regulated and 14 down-regulated) in PM/DM patients compared to HCs. Four miRNAs (miR-320a, miR-335-3p, miR-34a-5p and miR-454-3p) were chosen for real-time PCR validation. The expression of miR-34a-5p was significantly upregulated in PM/DM group (P < 0.05). In subgroup analysis, miR-34a-5p was significantly upregulated in interstitial lung disease (ILD) group and DM group (P < 0.001). The level of SIRT1, a validated target of miR-34a, was significantly lower in PBMCs of PM/DM patients compared with HCs.

Conclusions

MiR-34a-5p may potentially participate in the pathogenesis of PM/DM through SIRT1, and may serve as a potential new biomarker for PM/DM-ILD.

[Pulmonary involvement in idiopathic inflammatory myopathies]

Idiopathic inflammatory myopathies are rare systemic diseases with different types of pulmonary manifestations depending on the underlying aetiology; here, interstitial lung diseases (ILD) are the most frequently found patterns depending on the underlying disorder. There is a lack of sufficient prospective studies on this heterogeneous group of patients, particularly in case of ILD being involved. The diagnosis is based upon guideline recommendations for ILD and requires a multidisciplinary discussion within a team with specific expertise in this field. Myositis specific antibodies and myositis associated antibodies form an essential part of the diagnostic tools and may also be associated with a certain phenotype or disease progression. Anti-t-RNA-synthetase antibodies (Anti-ARS) and anti-melanoma differentiation-associated gene 5 antibodies (MDA5) play an important clinical role for treatment the estimation of response and prognosis. The most common ILD patterns are nonspecific interstitial pneumonia (NSIP) and organising pneumonia (OP) or a mixed pattern of both. Treatment is based on systemic steroids and early initiation of other immunosuppressant drugs. Evidence for this is, however, sparse, since most of the studies having investigated treatment modalities are of retrospective nature, even though some new prospective data may be useful for the establishment of treatment pathways in the future.

Clinical Features and Outcomes of Patients with Idiopathic Inflammatory Myositis-Associated Interstitial Lung Disease in Rural Appalachia: A Cross-Sectional Study

BACKGROUND

Idiopathic inflammatory myopathies (IIMs) are a group of autoimmune disorders often complicated by interstitial lung disease (ILD). The clinical characteristics and outcomes of IIM-associated ILD have been reported variably, but the literature on rural populations is scarce.

METHODS

A retrospective cross-sectional study was conducted at a rural tertiary academic medical center. Twenty-nine patients met the final inclusion criteria. The primary outcome was to assess the disease state and immunological and radiographic features of IIM-associated ILD. Secondary outcomes included disease progression, ILD exacerbation, mortality rate, and factors associated with poor outcome.

RESULTS

Dermatomyositis (n = 15, 51.72%) followed by polymyositis (n = 8, 27.58%) were predominant myopathies. The most common autoantibodies were anti-Jo1 antibodies (n = 11, 37.93%). Indeterminate usual interstitial pneumonitis (41.30%, n = 12) was the most common radiographic pattern followed by non-specific interstitial pneumonia (n = 5, 17.24%). ILD exacerbation (n = 14, 66.66%) and mortality rate (n = 6, 20.69%) were high. Albumin levels were significantly lower in patients who died.

CONCLUSIONS

The clinical characteristics of patients with IIM-associated ILD in rural Appalachia exhibit notable distinctions, and outcomes are worse compared to other populations. Larger studies are needed to investigate other prognostics factors and longitudinal trends of clinical characteristics and outcomes of IIM-associated ILD in rural populations.

Anti-MDA5 antibody-associated clinically amyopathic dermatomyositis diagnosed after the onset of pulmonary hypertension

Idiopathic inflammatory myopathies (IIM) are a group of highly heterogeneous systemic autoimmune diseases, of which clinically amyopathic dermatomyositis (CADM) is a distinct sub-type. Pulmonary hypertension (PH) is a life-threatening medical condition that can occur as a complication of connective tissue diseases. Herein, our report first suggests that PH can develop in CADM. A 48-year-old woman came to our hospital due to a 3 months history of facial edema and shortness of breath. Relevant examinations revealed Gottron's sign, normal creatinine kinase levels, elevated levels of mean pulmonary artery pressure, double-positive anti-MDA5 and anti-Ro52 antibodies, and typical pathological changes associated with myositis. The diagnosis of CADM combined with PH was considered. The patient responded well to the immunosuppression therapy and PH-related drug therapy. We provide further insights that patients with IIM need to undergo regular assessment of PH.

Advances in the identification and management of progressive pulmonary fibrosis: perspective from Chinese experts

Fibrosing interstitial lung diseases (FILDs) other than idiopathic pulmonary fibrosis (IPF) can develop into progressive pulmonary fibrosis (PPF) despite initial management. A substantial proportion of patients with non-IPF interstitial lung diseases (ILDs) progress to PPF, including connective tissue disease-associated ILD (such as rheumatoid arthritis-associated ILD, systemic sclerosis-associated ILD, and idiopathic inflammatory myositis-associated ILD), fibrosing hypersensitivity pneumonitis, and fibrosing occupational ILD. The concept of PPF emerged only recently and several studies have confirmed the impact of PPF on mortality. In addition to poor prognosis among patients with PPF, there remains a lack of consensus in the diagnosis and treatment of PPF across different types of ILDs. There is a need to raise awareness of PPF in FILDs and to explore measures to improve PPF diagnosis and treatment, which in turn could potentially reduce the progression from FILD to PPF. This review discusses the disease burden of PPF and recent advances in the management of PPF among patients with ILDs, including antifibrotic medications that have emerged as promising treatment options. Additionally, this review highlights the perspectives of expert Chinese physicians with regard to their experience in managing PPF in clinical practice.

Prevalence of myositis specific and associated antibodies in a cohort of patients affected by idiopathic NSIP and no hint of inflammatory myopathies

The presence of interstitial lung disease (ILD) is a common and fearsome feature of idiopathic inflammatory myopathies (IIM). Such patients show radiological pattern of non-specific interstitial pneumonia (NSIP). The present study aimed to assess the prevalence of myositis-specific and myositis-associated antibodies (MSA and MAA) in a cohort of patients with a previous diagnosis of NSIP and no sign or symptom of IIM. Secondly, it will be assessed whether patients displaying MSA and/or MAA positivity have a worse or a better outcome than idiopathic NSIP. All patients affected by idiopathic NSIP were enrolled. MSA and MAA were detected using EUROLINE Autoimmune Inflammatory Myopathies 20 Ag (Euroimmun Lubeck, Germany), line immunoassay. A total of 16 patients (mean age 72 ± 6.1 years old) were enrolled. Six out of 16 patients (37.5%) had significant MSA and/or MAA positivity: one displayed positivity of anti-PL-7 (+ +), one of anti-Zo (+ +), anti-TIF1γ (+ + +) and anti-Pm-Scl 75 (+ + +), one of anti-Ro52 (+ +), one of anti-Mi2β (+ + +), one of anti-Pm-Scl 75 (+ + +) and the latter of both anti-EJ (+ + +) and anti-Ro52 (+ + +).Two out of 7 seropositive patients showed a significant impairment of FVC (relative risk 4.8, 95% CI 0.78-29.5; p = 0.0350). Accordingly, among the 5 patients that started antifibrotic treatment during the observation time, 4 were seronegative. Our findings highlighted a potential autoimmune or inflammatory in idiopathic NSIP patients and also in those without significant rheumatological symptoms. A more accurate diagnostic assessment may ameliorate diagnostic accuracy as well as may provide new therapeutic strategy (antifibrotic + immunosuppressive). A cautious assessment of NSIP patients with a progressive and non-responsive to glucocorticoids disease course should therefore include an autoimmunity panel comprising MSA and MAA.

Serum bilirubin levels in primary Sjögren's syndrome: an association with interstitial lung disease

OBJECTIVE

We aimed to assess the association between serum bilirubin levels and interstitial lung disease (ILD) in patients with Primary Sjögren's syndrome (pSS).

MATERIALS AND METHODS

The retrospectively analysis included 89 consecutive patients with pSS, we collected the clinical materials of pSS patients from the electronic medical records, and all pSS patients were divide into pSS with ILD group and pSS without ILD group.

RESULTS

Serum bilirubin levels were significantly lower in pSS patients with ILD than those without ILD (p = 0.010). Serum bilirubin levels showed a significant negative correlation with erythrocyte sedimentation rate (ESR) (r = -0.321, p = 0.002) in patients with pSS. A multivariable logistic regression analysis confirmed that serum bilirubin presented an independent association with ILD in patients with pSS (OR = 0.841, 95%CI:0.728-0.972, p = 0.019).

CONCLUSION

Serum bilirubin is independently associated with ILD and therefore may be a promising marker of ILD in patients with pSS.

Anti-Cytosolic 5'-Nucleotidase 1A in the Diagnosis of Patients with Suspected Idiopathic Inflammatory Myopathies: An Italian Real-Life, Single-Centre Retrospective Study

BACKGROUND

Anti-cytosolic 5'-nucleotidase 1A (anti-cN1A) antibodies were proposed as a biomarker for the diagnosis of inclusion body myositis (IBM), but conflicting specificity and sensitivity evidence limits its use. Our study aimed to assess the diagnostic accuracy of anti-cN1A in a cohort of patients who underwent a myositis line immunoassay for suspected idiopathic inflammatory myopathies (IIM). We also assessed the agreement between two testing procedures: line immunoassay (LIA) and enzyme-linked immunoassay (ELISA).

MATERIALS AND METHODS

We collected retrospective clinical and serological data for 340 patients who underwent a myositis antibody assay using LIA (EUROLINE Autoimmune Inflammatory Myopathies 16 Ag et cN-1A (IgG) line immunoassay) and verification with an anti-cN1A antibody assay using ELISA (IgG) (Euroimmun Lubeck, Germany).

RESULTS

The serum samples of 20 (5.88%) patients (15 females, 5 males, mean age 58.76 ± 18.31) tested positive for anti-cN1A using LIA, but only two out of twenty were diagnosed with IBM. Seventeen out of twenty tested positive for anti-cN1A using ELISA (median IQR, 2.9 (1.9-4.18)).

CONCLUSIONS

Our study suggests excellent concordance between LIA and ELISA for detecting anti-cN1A antibodies. LIA may be a rapid and useful adjunct, and it could even replace ELISA for cN1A assay. However, the high prevalence of diseases other than IBM in our cohort of anti-cN1A-positive patients did not allow us to consider anti-cN1A antibodies as a specific biomarker for IBM.

Anti-Ro52/Anti-nuclear Matrix Protein 2 Positive Clinically Amyopathic Dermatomyositis Presented Only With Interstitial Lung Disease

This report contemplates a unique case of clinically amyopathic dermatomyositis (CADM) that presented as interstitial lung disease. The patient was a 55-year-old woman who showed up with progressive exercise intolerance and a dry cough without muscular or dermatological clinical manifestations. Diagnostic workup and imaging revealed the presence of interstitial lung disease, and further evaluation led to a positive autoimmune panel for anti-nuclear matrix protein 2 (anti-NXP2) and anti-Ro52 antibodies, establishing the diagnosis of anti-NXP2 plus anti-Ro52 antibodies-positive amyopathic idiopathic inflammatory dermatomyositis. The patient was started on intravenous corticosteroids. She showed improvement on her chest X-ray (CXR) and was then switched to oral corticosteroids. After six months of steroid treatment, corticosteroids were stopped, and the patient was re-evaluated one month later disease relapse.

Myositis interstitial lung disease and autoantibodies

The aim of this review is to examine and evaluate published literature associated with idiopathic inflammatory myopathies (IIM) and interstitial lung disease (ILD) based on myositis specific autoantibodies (MSA) and the potential clinical significance of each autoantibody subtype for the practicing clinician. The review is a comprehensive search of literature published in PubMed from the year 2005 and onward coinciding with the surge in the discovery of new MSAs. Additionally, we comment on recommended multidisciplinary longitudinal care practices for patients with IIM-ILD with regard to imaging and other testing. Treatment is not covered in this review.

Diagnosis and treatment of interstitial lung disease related to systemic autoimmune myopathies: a narrative review

Systemic autoimmune myopathies (SAMs) are rare diseases that lead to muscle inflammation and may be associated with a variety of systemic manifestations. Although there is great heterogeneity in the spectrum of extra-muscular involvement in SAMs, interstitial lung disease (ILD) is the most frequent lung manifestation. SAM-related ILD (SAM-ILD) presents significant variations according to geographic location and temporal trends and is associated with increased morbidity and mortality. Several myositis autoantibodies have been discovered over the last decades, including antibodies targeting aminoacyl-tRNA synthetase enzymes, which are associated with a variable risk of developing ILD and a myriad of other clinical features. In this review, the most relevant topics regarding clinical manifestations, risk factors, diagnostic tests, autoantibodies, treatment, and prognosis of SAM-ILD are highlighted. We searched PubMed for relevant articles published in English, Portuguese, or Spanish from January 2002 to September 2022. The most common SAM-ILD patterns are nonspecific interstitial pneumonia and organizing pneumonia. The combination of clinical, functional, laboratory, and tomographic features is usually sufficient for diagnostic confirmation, without the need for additional invasive methods. Glucocorticoids remain the first-line treatment for SAM-ILD, although other traditional immunosuppressants, such as azathioprine, mycophenolate, and cyclophosphamide have demonstrated some efficacy and, therefore, have an important role as steroid-sparing agents.

Role of CD14+ monocyte-derived oxidised mitochondrial DNA in the inflammatory interferon type 1 signature in juvenile dermatomyositis

OBJECTIVES

To define the host mechanisms contributing to the pathological interferon (IFN) type 1 signature in Juvenile dermatomyositis (JDM).

METHODS

RNA-sequencing was performed on CD4+, CD8+, CD14+ and CD19+ cells sorted from pretreatment and on-treatment JDM (pretreatment n=10, on-treatment n=11) and age/sex-matched child healthy-control (CHC n=4) peripheral blood mononuclear cell (PBMC). Mitochondrial morphology and superoxide were assessed by fluorescence microscopy, cellular metabolism by 13C glucose uptake assays, and oxidised mitochondrial DNA (oxmtDNA) content by dot-blot. Healthy-control PBMC and JDM pretreatment PBMC were cultured with IFN-α, oxmtDNA, cGAS-inhibitor, TLR-9 antagonist and/or n-acetyl cysteine (NAC). IFN-stimulated gene (ISGs) expression was measured by qPCR. Total numbers of patient and controls for functional experiments, JDM n=82, total CHC n=35.

RESULTS

Dysregulated mitochondrial-associated gene expression correlated with increased ISG expression in JDM CD14+ monocytes. Altered mitochondrial-associated gene expression was paralleled by altered mitochondrial biology, including 'megamitochondria', cellular metabolism and a decrease in gene expression of superoxide dismutase (SOD)1. This was associated with enhanced production of oxidised mitochondrial (oxmt)DNA. OxmtDNA induced ISG expression in healthy PBMC, which was blocked by targeting oxidative stress and intracellular nucleic acid sensing pathways. Complementary experiments showed that, under in vitro experimental conditions, targeting these pathways via the antioxidant drug NAC, TLR9 antagonist and to a lesser extent cGAS-inhibitor, suppressed ISG expression in pretreatment JDM PBMC.

CONCLUSIONS

These results describe a novel pathway where altered mitochondrial biology in JDM CD14+ monocytes lead to oxmtDNA production and stimulates ISG expression. Targeting this pathway has therapeutical potential in JDM and other IFN type 1-driven autoimmune diseases.

Spontaneous Pneumomediastinum and Subcutaneous Emphysema in Dermatomyositis: A Case Series and Literature Review

Background

Spontaneous pneumomediastinum and subcutaneous emphysema are rare and serious complications of dermatomyositis (DM).

Case Presentation

Our article presents two clinically heterogeneous cases of DM who developed pneumomediastinum and subcutaneous emphysema. The first was a 24-year-old lady with a recently diagnosed DM. She developed rapidly progressive pneumonia, interstitial lung disease (ILD), pneumomediastinum, subcutaneous emphysema, and acute respiratory distress syndrome (ARDS). She died despite treatment with steroids and immunosuppressants (methotrexate and mycophenolate mofetil (MMF)). The second was a 30-year-old man diagnosed with amyopathic DM. He developed pneumomediastinum prior to ILD, which worsened over time, and subcutaneous emphysema evolved. However, he recovered completely after corticosteroid, MMF, and rituximab.

Conclusion

Spontaneous pneumomediastinum and subcutaneous emphysema may complicate DM. Corticosteroids, immunosuppressants, and respiratory support are the mainstay of management for these conditions. Though they were reported to carry a poor prognostic value, the course and outcome are highly variable among the cases.

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.

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.

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.

Accuracy of power Doppler ultrasonography in the diagnosis and monitoring of idiopathic inflammatory myopathies

OBJECTIVES

No clear-cut guidelines exist for the use of imaging procedures for the diagnosis of idiopathic inflammatory myopathies (IIM). The aim of the present study was to assess the diagnostic accuracy of power Doppler ultrasonography (PDUS) score in IIM patients compared with a control group and its usefulness during follow-up.

METHODS

All patients evaluated in the Vasculitis and Myositis Clinic, Rheumatology Unit, University of Siena were prospectively collected. All patients underwent US examination of both thighs in axial and longitudinal scans, which were also performed twice (T1) or three times (T2).

RESULTS

Forty-five patients with IIM (median [interquartile range] age 55 [45-66] years; 35 female) were enrolled. Receiver operating characteristic curves distinguished patients and controls based on ∑power Doppler (PD), ∑oedema, ∑atrophy and CRP. The best cut-off value for ∑PD was 0.5, ∑oedema 1.5, ∑atrophy 0.5 and CRP 0.22 mg/dl. In a logistic regression analysis, the variables that most influenced diagnosis of IIM were ∑PD and ∑oedema (P = 0.017 and P = 0.013, respectively). ∑Oedema was lower at T1 (P = 0.0108) and T2 (P = 0.0012) than at T0. Likewise, ∑PD was lower at T1 (P = 0.0294) and T2 (P = 0.0420) than at T0. Physician global assessment was lower at T1 (P = 0.0349) and T2 (P = 0.0035) than at baseline.

CONCLUSION

Our findings show that PDUS is a reliable diagnostic tool in the differential diagnosis between inflammatory and non-inflammatory myopathies. Moreover, PDUS can be employed also during the follow-up of patients with IIM. A reduction in disease activity, measured by physician global assessment, led to a concomitant decrease in both oedema and PD, which was directly correlated with their rate of change. This underlines the close link between clinical assessment and PDUS findings, not only at diagnosis but also during monitoring.

Autoimmune Pulmonary Alveolar Proteinosis during the Treatment of Idiopathic Inflammatory Myopathy

Approximately 50% of idiopathic inflammatory myopathies (IIMs) are associated with interstitial lung disease (ILD). Typically, IIM-ILD manifests as nonspecific interstitial pneumonia. We herein report a rare case of a 78-year-old man with autoimmune pulmonary alveolar proteinosis (PAP) that developed during IIM treatment. The diagnosis of autoimmune PAP was based on detecting anti-granulocyte-macrophage colony-stimulating factor antibodies. We postulated that PAP may have been induced by IIM treatment with prednisolone. Our case suggests that the possibility of autoimmune PAP should be considered in patients with lung lesions during the clinical course of IIM.

Human epididymis protein 4 as a clinical biomarker in identifying interstitial lung disease in patients with idiopathic inflammatory myopathies

OBJECTIVE

Human epididymis protein 4 (HE4) can differentiate interstitial lung disease from patients with some rheumatic diseases. However, the clinical utility of HE4 in idiopathic inflammatory myopathies (IIM) remains unclear.

METHODS

80 IIM patients and 91 age and gender-matched healthy controls (HCs) were recruited. Clinical and laboratory data were recorded at baseline and 12 weeks. HE4 was tested by the method of electrochemical luminescence.

RESULTS

Compared to HCs, the levels of HE4 significantly elevated in IIM patients. Patients with elevated HE4 had a higher interstitial lung disease (ILD) prevalence. Among patients with ILD, histological patterns of organizing pneumonia had higher HE4 levels than non-specific interstitial pneumonia. Further, there was a positive correlation between HE4 and the semi-quantitative CT grade (r = 0.778, p < 0.001) and a negative relation between HE4 and the percentage of forced vital capacity (p < 0.001) and diffusing capacity of the lung for carbon monoxide (DLco) (p = 0.001). An optimal cut-off value of HE4 (79.6 pmol/L) for distinguishing IIM-ILD was analyzed by ROC analysis with an AUC of 0.733 (p = 0.002). Regression analysis revealed that elevated HE4 independently identified IIM-related ILD (OR 34.8, 95 %CI, 3.58-338.14, p = 0.002). With the improvement after treatment, serum HE4 levels were significantly decreased (p = 0.006), accompanied by improved DLco% (p = 0.012).

CONCLUSIONS

Serum HE4 was significantly elevated in patients with IIM and may be utilized as a serum biomarker to evaluate the disease severity and prognosis of IIM-related ILD.

Clinical features and outcomes of patients with myositis associated-interstitial lung disease

Introduction

Myositis associated interstitial lung disease (ILD) seems to be an under-recognized entity.

Methods

In this multicenter, retrospective study, we recorded between 9/12/2019 and 30/9/2021 consecutive patients who presented in five different ILD centers from two European countries (Greece, France) and received a multidisciplinary diagnosis of myositis associated-ILD. The primary outcome was all-cause mortality over 1 year in specific subgroups of patients. Secondary outcomes included comparison of disease characteristics between patients diagnosed with the amyopathic subtype and patients with evidence of myopathy at diagnosis.

Results

We identified 75 patients with myositis associated-ILD. Median age (95% CI) at the time of diagnosis was 64.0 (61.0-65.0) years. Antinuclear antibody testing was positive in 40% of the cohort (n = 30/75). Myopathy onset occurred first in 40.0% of cases (n = 30), ILD without evidence of myopathy occurred in 29 patients (38.7%), while 16 patients (21.3%) were diagnosed concomitantly with ILD and myopathy. The commonest radiographic pattern was cellular non-specific interstitial pneumonia (NSIP) and was observed in 29 patients (38.7%). The radiographic pattern of organizing pneumonia was significantly more common in patients diagnosed with the amyopathic subtype compared to patients that presented with myopathy [24.1% (n = 7/29) vs. 6.5% (n = 3/46), p = 0.03]. One year survival was 86.7% in the overall population. Kaplan-Meier analysis demonstrated significantly higher all-cause 1-year mortality in patients with the amyopathic subtype compared to patients with evidence of myopathy [H R 4.24 (95% CI: 1.16-15.54), p = 0.03]. Patients diagnosed following hospitalization due to acute respiratory failure experienced increased risk of 1-year all-cause mortality compared to patients diagnosed in outpatient setting [HR 6.70 (95% CI: 1.19-37.81), p = 0.03]. Finally, patients with positive anti-MDA5 presented with higher 1-year all-cause mortality compared to anti-MDA5 negative patients [HR 28.37 (95% CI: 5.13-157.01), p = 0.0001].

Conclusion

Specific ILD radiographic patterns such as NSIP and organizing pneumonia may herald underlying inflammatory myopathies. Hospitalized patients presenting with bilateral organizing pneumonia refractory to antibiotics should be meticulously evaluated for myositis associated-ILD even if there is no overt muscular involvement. Incorporation of ILD radiological patterns in the diagnostic criteria of inflammatory myopathies may lead to timely therapeutic interventions and positively impact patients' survival.

Validation of methods to identify people with idiopathic inflammatory myopathies using hospital episode statistics

OBJECTIVE

Hospital episode statistics (HES) are routinely recorded at every hospital admission within the National Health Service (NHS) in England. This study validates diagnostic ICD-10 codes within HES as a method of identifying cases of idiopathic inflammatory myopathies (IIMs).

METHODS

All inpatient admissions at one NHS Trust between 2010 and 2020 with relevant diagnostic ICD-10 codes were extracted from HES. Hospital databases were used to identify all outpatients with IIM, and electronic care records were reviewed to confirm coding accuracy. Total hospital admissions were calculated from NHS Digital reports. The sensitivity and specificity of each code and code combinations were calculated to develop an optimal algorithm. The optimal algorithm was tested in a sample of admissions at another NHS Trust.

RESULTS

Of the 672 individuals identified by HES, 510 were confirmed to have IIM. Overall, the positive predictive value (PPV) was 76% and sensitivity 89%. Combination algorithms achieved PPVs between 89 and 94%. HES can also predict the presence of IIM-associated interstitial lung disease (ILD) with a PPV of 79% and sensitivity of 71%. The optimal algorithm excluded children (except JDM code M33.0), combined M33.0, M33.1, M33.9, M36.0, G72.4, M60.8 and M33.2, and included M60.9 only if it occurred alongside an ILD code (J84.1, J84.9 or J99.1). This produced a PPV of 88.9% and sensitivity of 84.2%. Retesting this algorithm at another NHS Trust confirmed a high PPV (94.4%).

CONCLUSION

IIM ICD-10 code combinations in HES have high PPVs and sensitivities. Algorithms tested in this study could be applied across all NHS Trusts to enable robust and cost-effective whole-population research into the epidemiology of IIM.

Interstitial disease associated with connective tissue disease and vasculitis

Systemic autoimmune diseases comprise a complex, heterogeneous group of entities. Noteworthy among the pulmonary complications of these entities is interstitial involvement, which manifests with the same radiopathologic patterns as in idiopathic interstitial pneumonia. High-resolution computed tomography is the gold-standard imaging technique; it enables us to identify and classify the disease and to determine its extent, providing useful information about the prognosis. In this group of processes, the most common pattern of presentation is nonspecific interstitial pneumonia. It is essential for radiologists to work together in collaboration with other specialists to reach the correct diagnosis and enable appropriate, integrated treatment.

Clinical and Radiological Features of Interstitial Lung Diseases Associated with Polymyositis and Dermatomyositis

Polymyositis and dermatomyositis are autoimmune idiopathic systemic inflammatory diseases, characterized by various degrees of muscle inflammation and typical cutaneous lesions-the latter found in dermatomyositis. The underlying pathogenesis is characterized by a high level of uncertainty, and recent studies suggest diseases may have different immunopathological mechanisms. In polymyositis, components of the cellular immune system are involved, whereas in dermatomyositis, the pathogenesis is mainly mediated by the humoral immune response. The interstitial lung disease occurs in one-third of polymyositis and dermatomyositis patients associated with worse outcomes, showing an estimated excess mortality rate of around 40%. Lung involvement may also appear, such as a complication of muscle weakness, mainly represented by aspiration pneumonia or respiratory insufficiency. The clinical picture is characterized, in most cases, by progressive dyspnea and non-productive cough. In some cases, hemoptysis and chest pain are found. Onset can be acute, sub-acute, or chronic. Pulmonary involvement could be assessed by High Resolution Computed Tomography (HRCT), which may identify early manifestations of diseases. Moreover, Computed Tomography (CT) appearances can be highly variable depending on the positivity of myositis-specific autoantibodies. The most common pathological patterns include fibrotic and cellular nonspecific interstitial pneumonia or organizing pneumonia; major findings observed on HRCT images are represented by consolidations, ground-glass opacities, and reticulations. Other findings include honeycombing, subpleural bands, and traction bronchiectasis. In patients having Anti-ARS Abs, HRCT features may develop with consolidations, ground glass opacities (GGOs), and reticular opacities in the peripheral portions; nonspecific interstitial pneumonia or nonspecific interstitial pneumonia mixed with organizing pneumonia have been reported as the most frequently encountered patterns. In patients with anti-MDA5 Abs, mixed or unclassifiable patterns are frequently observed at imaging. HRCT is a sensitive method that allows one not only to identify disease, but also to monitor the effectiveness of treatment and detect disease progression and/or complications; however, radiological findings are not specific. Therefore, aim of this pictorial essay is to describe clinical and radiological features of interstitial lung diseases associated with polymyositis and dermatomyositis, emphasizing the concept that gold standard for diagnosis and classification-should be based on a multidisciplinary approach.