Antisynthetase syndrome: Pulmonary computed tomography findings of adult patients with antibodies to aminoacyl-tRNA synthetases

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.

Comparison of Chest High-Resolution Computed Tomography Findings in Patients with Anti-Melanoma Differentiation-Associated Gene 5 Antibody-Positive and Antibody-Negative Progressive Pulmonary Fibrosis with Polymyositis/Dermatomyositis

Background/Objectives: This study compared chest high-resolution computed tomography (HRCT) findings between patients with anti-melanoma differentiation-associated gene 5 (MDA5) antibody-positive and antibody-negative progressive pulmonary fibrosis (PPF) with polymyositis/dermatomyositis (PM/DM). Methods: Of the 85 patients with PM/DM-interstitial lung disease (ILD), 17 were anti-MDA5 antibody-positive, and 68 were antibody-negative. Among these, 5 anti-MDA5 antibody-positive and 9 antibody-negative cases met the criteria for PPF and were enrolled in the study. The chest HRCT findings and the duration from treatment initiation to the appearance of key fibrotic changes were analyzed. Results: In the anti-MDA5-positive group, all patients were diagnosed with PPF within 6 months of treatment initiation, compared to only 22.2% in the anti-MDA5-negative group. While there was no difference between the anti-MDA5 antibody-positive and antibody-negative groups in terms of chest HRCT findings associated with PPF, the duration to the appearance of increased traction bronchiectasis and bronchiolectasis, and new ground-glass opacity with traction bronchiectasis was significantly shorter in the anti-MDA5-positive group (p = 0.016 and p = 0.023, respectively). The appearance of new fine reticulations and increased coarseness of reticular abnormalities tended to be shorter in the anti-MDA5 antibody-positive group than in the antibody-negative group. Conclusions: Pulmonary fibrosis in patients with anti-MDA5 antibody-positive ILD can rapidly progress within 6 months, despite immunosuppressive therapy. Frequent HRCT monitoring and early combination therapy with antifibrotic agents are crucial for managing the progression of fibrosis.

Idiopathic Inflammatory Myopathies-Associated Interstitial Lung Disease in Adults

Idiopathic inflammatory myopathies (IIM) are a heterogeneous group of autoimmune diseases characterized by muscle involvement and various extramuscular manifestations. Interstitial lung disease (ILD) is one of the most common extramuscular manifestations of IIM and is associated with significant mortality and morbidity. The clinical phenotypes, treatment responses, and prognosis of IIM-ILD are significantly related to myositis-specific antibody (MSA) profiles, with some racial differences. The features associated with MSA in IIM-ILD could also be relevant to cases of ILD where MSA is present but does not meet the criteria for IIM. The anti-melanoma differentiation-associated gene 5 antibody is highly associated with rapidly progressive ILD (RP-ILD), especially in Asian populations, and with characteristic cutaneous manifestations, such as skin ulcers. Radiologically, ground-glass opacities, consolidations, and nonsegmental linear opacities were more predominant than reticular opacities and honeycombing. While the mortality rate is still around 30%, the prognosis can be improved with early intensive therapy with corticosteroids and multiple immunosuppressants. In contrast, anti-aminoacyl-tRNA synthetase (ARS) antibodies are associated with chronic ILD, although RP-ILD is also common. Patients with anti-ARS antibodies often show lung-predominant presentations, with subtle muscle and skin involvement. Radiologically, reticular opacities, with or without consolidation, are predominant and may progress to honeycombing over time. Combination therapy with corticosteroids and a single immunosuppressant is recommended to prevent relapses, which often lead to a decline in lung function and fatal long-term outcomes. Significant advances in immunology and genetics holds promise for fostering more personalized approaches to managing IIMILD.

Lung ultrasound in the assessment of interstitial lung disease in patients with connective tissue disease: Performance in comparison with high-resolution computed tomography

OBJECTIVE

To investigate clinical relevance of performing lung ultrasound (LUS) in patients with connective tissue disease (CTD)-associated interstitial lung disease (ILD) in comparison with high-resolution computed tomography (HRCT).

METHODS

This single-centre study enrolled eligible patients with CTD-ILD from the prospective LUS registry. Total B-lines were detected by assessment at 14 sites via LUS. Forced vital capacity, diffusing lung capacity for carbon monoxide (DLCO), DLCO/alveolar volume, 6-minute walking distance, and the ILD-GAP index were used as ILD prognostic parameters. Correlations were examined using single and multiple regression analyses.

RESULTS

Sixty-seven patients were enrolled, including 29 with idiopathic inflammatory myopathy or anti-synthetase syndrome, 25 with systemic sclerosis (SSc), 10 with rheumatoid arthritis, and 3 with mixed CTD. The total number of B-lines correlated with ILD extent on HRCT in patients with CTD-ILD (r = 0.66; P < .001), particularly in patients with SSc-ILD (r = 0.78; P < .001). Total B-lines and ILD extent on HRCT showed comparable correlations with prognostic parameters, while multiple regression analysis revealed the limited benefit of performing LUS in addition to HRCT in predicting correlations with prognostic factors.

CONCLUSIONS

LUS serves as an alternative tool for assessing the severity and prognosis of patients with CTD-ILD.

Longitudinal Study of Patients with Connective Tissue Disease-Interstitial Lung Disease and Response to Mycophenolate Mofetil and Rituximab

Background/Objective: To investigate the effect of mycophenolate mofetil (MMF) and rituximab (RTX) on pulmonary function test (PFT) results in a mixed cohort of patients with connective tissue disease-associated interstitial lung disease (CTD-ILD), longitudinally followed up for 1 year in a single academic center. Methods: Patients with CTD-ILD were identified in electronic medical records from 1 January 2009 to 30 April 2019. Prescribed MMF and RTX doses, dosage changes, and therapy plans were analyzed individually with improvement in PFT outcomes determined using multivariable linear regression models during 12-month follow-up. Results: Forty-seven patients with CTD-ILD, treated with MMF, RTX, or both, were included. Patients on combined MMF and RTX had worse PFT outcomes at baseline compared with patients on monotherapy. Substantial improvement was observed among all PFT outcomes from baseline to 12 months, regardless of medication dosage or therapy plans. The diffusing capacity of the lungs for carbon monoxide (DLCO) worsened by an average of 7.21 mL/(min*mmHg) (95% CI, 4.08-10.33; p < 0.001) among patients on RTX compared to combined therapy. Patients on higher doses of MMF at baseline experienced an average increase of 0.93 (95% CI, 0.04-1.82) units in DLCO from baseline to 6 months (p = 0.04) and a 2.79% (95% CI, 0.61-4.97%) increase in DLCO from 6 to 12 months (p = 0.02) within patients on concurrent RTX at 6-month follow-up. Conclusions: The treatment of CTD-ILD with MMF and/or RTX was associated with overall improvement in PFT outcomes. Combined therapy resulted in significant improvements in DLCO compared with monotherapy. Higher doses of MMF also provided greater improvements in DLCO.

Relationship between high-resolution computed tomography quantitative imaging analysis and physiological and clinical features in antisynthetase syndrome-related interstitial lung disease

OBJECTIVES

To explore the association between the extent of CT abnormalities by quantitative imaging analysis (QIA) and clinical/physiological disease parameters in patients with antisynthetase syndrome associated interstitial lung disease (ARS-ILD).

METHODS

We analysed 20 patients with antisynthetase antibodies and active ILD enrolled in the Abatacept in Myositis-Associated Interstitial Lung Disease study. High-resolution chest CT was obtained at weeks 0, 24 and 48 and QIA scored the extent of ground glass (quantitative score for ground glass), fibrosis (quantitative score for lung fibrosis, QLF) and total ILD (quantitative ILD, QILD). Mixed-effects models estimated longitudinal QIA scores over time. Associations between QIA scores with clinical/physiological parameters were analysed longitudinally using repeated-measures mixed-effects models.

RESULTS

Patients were median age 57 years, 55% males and 85% white. Higher (worse) baseline QIA scores correlated with lower baseline forced vital capacity (FVC) and diffusing capacity adjusted for haemoglobin (DLCO). Longitudinal QIA trajectories trended towards improving scores during the trial, and patients on O2 at baseline had worsening QIA trajectories which were different from patients who were not on O2. Longitudinal QIA scores demonstrated strong associations with both FVC and DLCO over time. Higher QILD scores over time were also associated with worse dyspnoea scores, pulmonary visual analogue scale, physician and patient global disease activity, health status in 6/8 domains of the Short Form-36 and higher oxygen requirements. Patients with significant radiographic improvement at 48 weeks had higher baseline QLF, QILD and worse DLCO.

CONCLUSIONS

Longitudinal QIA scores associate with lung physiology, patient perception of respiratory status, overall disease activity and quality of life over time in ARS-ILD. QIA may allow reproducible monitoring of disease progression and response to therapy over time.

TRIAL REGISTRATION NUMBER

NCT03215927.

Secondary Pulmonary Alveolar Proteinosis Development during the Treatment for Anti-aminoacyl-tRNA Synthetase Antibody-positive Interstitial Lung Disease

A 70-year-old woman with anti-aminoacyl-tRNA synthetase (ARS) antibody-positive interstitial lung disease (ARS-ILD) received daily medications and regular cyclophosphamide cycles for recurring exacerbations. Approximately four years after immunosuppression initiation, the patient was admitted for progressive dyspnea on exertion. Chest computed tomography (CT) findings were suggestive of acute exacerbation. Despite intensified immunosuppressive treatment, the radiographic findings worsened, and serum Krebs von den Lungen-6 (KL-6) levels increased. A bronchoalveolar lavage fluid (BALF) examination revealed amorphous globules and alveolar macrophages with eosinophilic granules. Owing to negative anti-granulocyte-macrophage colony-stimulating factor antibody tests, a diagnosis of secondary pulmonary alveolar proteinosis (PAP) was established.

Interstitial lung disease associated with anti-aminoacyl-tRNA synthetase syndrome: quantitative evaluation of CT after initial treatment and long-term follow-up

BACKGROUND

Visual evaluation of interstitial lung disease (ILD)-related changes can generate intra- and inter-observer errors. However, recent deep learning (DL) algorithm advances have facilitated accurate lung segmentation, lesion characterization, and quantification.

PURPOSE

To evaluate the treatment response and long-term course in ILD associated with anti-aminoacyl-tRNA synthetase syndrome (anti-ARS ILD) using a DL algorithm.

MATERIAL AND METHODS

Patients with anti-ARS ILD who underwent both pre- and post-initial-treatment computed tomography (CT) (n = 68) were divided into two groups (responders and non-responders) according to forced vital capacity improvement after initial treatment. We also analyzed the CT images of patients for whom long-term follow-up CT (>5 years) was performed after post-treatment CT (n = 43). DL analysis was used to classify CT imaging features into five patterns: normal; ground-glass opacity (GGO); consolidation; fibrotic lesions; and emphysema.

RESULTS

The initial responder group had a larger volume of consolidation. Consolidation and GGO volumes decreased after initial treatment in both groups. However, whole-lung and normal-area volumes increased in the responder group; conversely, there was no significant increase in the non-responder group. At the long-term follow-up, fibrotic lesions significantly increased in both groups. The emphysema pattern increased significantly in both groups after initial treatment and long-term follow-up. Six of 26 (23.1%) responders and 8 of 17 (47.1%) non-responders were judged as having progressive pulmonary fibrosis.

CONCLUSION

DL-based analysis facilitated the chronological evaluation of anti-ARS ILD. During the long-term follow-up, anti-ARS ILD was associated with chronological progression, regardless of initial treatment efficacy.

Anti-aminoacyl tRNA synthetase antibodies showing the discrepancy between enzyme-linked immunosorbent assay and RNA-immunoprecipitation

Anti-aminoacyl-tRNA synthetase (ARS) antibodies are myositis-specific antibodies associated with anti-synthetase syndrome (ASSD). Some patients are positive for anti-ARS antibodies on enzyme-linked immunosorbent assay (ELISA) but negative on RNA-immunoprecipitation (RNA-IP) (the gold standard method). Whether these patients should be considered truly positive for anti-ARS antibodies remains unclear. Therefore, we investigated the clinical characteristics of these patients and verified the authenticity of their anti-ARS positivity. Patients who were positive for anti-ARS antibodies on ELISA were divided into the non-discrepant (positive on RNA-IP, n = 52) and discrepant (negative on RNA-IP, n = 8) groups. Patient clinical characteristics were compared between the groups. For each positive individual, the authenticity of anti-ARS antibody positivity on ELISA was cross-examined using protein-IP and western blotting. All patients in the discrepant group had lung involvement, including five (63%) with interstitial lung disease. The overall survival time was significantly lower in the discrepant group than in the non-discrepant group (p < 0.05). Validation tests confirmed the presence of anti-ARS antibodies in the sera of the discrepant group but indicated different reactivity from typical anti-ARS antibodies. In conclusion, some anti-ARS antibodies are detected by ELISA but not RNA-IP. Such anti-ARS antibody discrepancies need further elucidation to attain validation of the diagnostic process in ASSD.

A Review of Myositis-Associated Interstitial Lung Disease

There is a well-established relationship between different subsets of idiopathic inflammatory myopathies (IIMs, myositis) and interstitial lung disease (ILD), with lung complications sometimes presenting prior to myopathic manifestations. The subtypes of myositis include those that are strongly associated with ILD, such as polymyositis (PM) and dermatomyositis (DM). Research has shown that in certain patients, these can then be further divided into subtypes using myositis-specific antibodies (MSAs), which are specific for myositis, and myositis-associated antibodies (MAAs), which can be found in myositis in overlap syndromes with other connective tissue diseases (CTDs). Notably, certain MSAs and MAAs are associated with ILD in patients with myositis. The clinical presentations of ILD in patients with myositis can vary widely and can be insidious in onset and difficult to diagnose. As ILD can progress rapidly in some cases, it is essential that clinicians are able to identify and diagnose ILD in patients with myositis. For this reason, the aim of this review is to highlight the clinical features, diagnostic criteria, important histopathologic, laboratory, and radiographic features, and treatment modalities for those patients with myositis-associated ILD.

Treatment with low-dose nintedanib and tacrolimus in patients with progressive fibrosing interstitial lung diseases with anti-ARS antibody-positive dermatomyositis

Nintedanib has been demonstrated to inhibit the rate of forced vital capacity decline in patients with progressive fibrosing interstitial lung diseases (PF-ILD) at a dose of 200 or 300 mg/day in the INBUILD trial. Although concomitant use of nintedanib with P-glycoprotein inhibitors reportedly increases the plasma concentrations of the former, tacrolimus, a P-glycoprotein inhibitor, is often used to treat connective tissue diseases-related interstitial lung diseases. The optimal dose of nintedanib in combination with tacrolimus for the treatment of PF-ILD with connective tissue disease is unknown. We herein present two patients with PF-ILD with anti-aminoacyl-tRNA synthetase antibody-positive dermatomyositis who were successfully treated with low-dose nintedanib (<200 mg/day) in combination with tacrolimus.

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.

Relationship between idiopathic interstitial pneumonias (IIPs) and connective tissue disease-related interstitial lung disease (CTD-ILD): A narrative review

While idiopathic interstitial pneumonia (IIP) centering on idiopathic pulmonary fibrosis (IPF) is the most prevalent interstitial lung disease (ILD), especially in the older adult population, connective tissue disease (CTD)-related ILD is the second most prevalent ILD. The pathogenesis of IPF is primarily fibrosis, whereas that of other ILDs, particularly CTD-ILD, is mainly inflammation. Therefore, a precise diagnosis is crucial for selecting appropriate treatments, such as antifibrotic or immunosuppressive agents. In addition, some patients with IIP have CTD-related features, such as arthritis and skin eruption, but do not meet the criteria for any CTD, this is referred to as interstitial pneumonia with autoimmune features (IPAF). IPAF is closely associated with idiopathic nonspecific interstitial pneumonia (iNSIP) and cryptogenic organizing pneumonia (COP). Furthermore, patients with iNSIP or those with NSIP with OP overlap frequently develop polymyositis/dermatomyositis after the diagnosis of IIP. Acute exacerbation of ILD, the most common cause of death, occurs more frequently in patients with IPF than in those with other ILDs. Although acute exacerbation of CTD-ILD occurs at a low rate of incidence, patients with rheumatoid arthritis, microscopic polyangiitis, or systemic sclerosis experience more acute exacerbation of CTD-ILD than those with other CTD. In this review, the features of each IIP, focusing on CTD-related signatures, are summarized, and the pathogenesis and appropriate treatments to improve the prognoses of patients with various ILDs are discussed.

Presenting clinical and imaging features of patients with clinically amyopathic interstitial lung disease associated with myositis-specific autoantibodies

Background

Lung involvement in the context of idiopathic inflammatory myopathies has significant impact on outcome; early and accurate diagnosis is important but can be difficult to achieve. In particular, patients without clinically evident muscle involvement pose a significant diagnostic challenge.

Methods

A computer-assisted search was conducted to identify patients with amyopathic interstitial lung disease associated with the presence of myositis-specific autoantibodies. Medical records and chest imaging studies were reviewed to identify clinical and radiologic features at presentation.

Results

Of the 35 patients with amyopathic interstitial lung disease associated with myositis-specific autoantibodies, the median age was 65 years (range 43-78) and 20 were women (57%). Of the patients, 34% had previously visited the rheumatology department. Presenting symptoms consisted of dyspnea (94%), cough (43%), and arthritis (23%). Raynaud phenomenon, "mechanic hands," Gottron papules, and inspiratory crackles were present in 23, 31, 9, and 74% of patients, respectively. After a detailed history, none of the patients reported muscle weakness, while four (11%) exhibited increased CK levels; of these four, two had a concomitant increase in aldolase levels. Median FVC was 79% predicted (range: 49-135) and median DLco was 50% predicted (range: 17-103). HRCT pattern was suggestive of an alternative to UIP pattern in 31/33 (94%) patients; the most common imaging patterns were NSIP (49%) and NSIP/OP (39%).

Conclusion

In patients with NSIP and NSIP/OP pattern, the presence of amyopathic interstitial lung disease associated with myositis-specific autoantibodies should be considered even in the absence of clinical evident myositis.

A Review of Antisynthetase Syndrome-Associated Interstitial Lung Disease

Our objective in this review article is to present a clinical case of a patient with antisynthetase syndrome (ASyS) and provide an overview of the pathogenesis, classification criteria, antibody profiles, clinical features, and current knowledge of treatment options, focusing on interstitial lung disease (ILD). ASyS is an uncommon autoimmune disease with a heterogenous clinical presentation characterized by the presence of autoantibodies against an aminoacyl-tRNA synthetase and manifested by myositis, fever, inflammatory arthritis, Raynaud's phenomenon, mechanics hands, and ILD. ASyS-associated ILD (ASyS-ILD) is the most serious complication of ASyS, which may evolve to rapidly progressive ILD; therefore, it often requires thorough clinical and radiologic evaluation including recognition of a specific clinical phenotype associated with the antisynthetase antibodies (ASAbs) to guide therapeutic interventions.

The Relationship Between Anti-SSA-52 and Interstitial Lung Disease

OBJECTIVE

The aims of this study were to assess whether a relationship between anti-SSA-52 and interstitial lung disease (ILD) can be further defined, and to enhance screening, detection, and potentially guide treatment.

METHODS

A historical cohort study of 201 patients was conducted at a single tertiary care center between January 1, 2016 and December 31, 2020. All included patients were anti-SSA-52 antibody positive. Chart review was performed for laboratory values, symptoms, pulmonary function tests, treatment, and imaging. Chest computed tomographies were reviewed by chest radiologists.

RESULTS

Among anti-SSA-52 antibody-positive patients, ILD was found in 125 (62.2%) compared with 76 (37.8%) with no ILD (p = 0.001). For those with ILD, 78 (62.4%) were diagnosed with connective tissue disease (CTD)-associated ILD, 28 (22.4%) were diagnosed ILD only, and 19 (15.2%) met the criteria for interstitial pneumonia with autoimmune features. In patients with CTD-ILD, 18 (23.0%) had their ILD diagnosis made over 6 months before a CTD diagnosis, and an additional 43 (55.1%) had their ILD and CTD diagnosed within 6 months of each other (p < 0.001). Common computed tomography patterns were nonspecific interstitial pneumonia/organizing pneumonia overlap in 44 (35.2%), 25 (20.0%) nonspecific interstitial pneumonia, and 15 (12%) usual interstitial pneumonia. Twenty-eight (35.9%) had antisynthetase syndrome, followed by 16 (20.5%) with dermatomyositis, 10 (12.8%) with CTD overlap, and 6 (7.7%) with systemic scleroderma.

CONCLUSIONS

There was a significant association between anti-SSA-52 antibodies and ILD across a wide spectrum of rheumatological diagnoses. A significant portion of patients were diagnosed with ILD either at the same time or before their CTD diagnosis. Further study will be needed to assess effective treatment and response.

Combination of Prednisolone and Calcineurin Inhibitors Prevents Lung Function Decline in Patients with Anti-aminoacyl-tRNA Synthetase Antibody-Positive Polymyositis/Dermatomyositis

OBJECTIVE

Anti-aminoacyl-tRNA synthetase antibody-positive polymyositis/dermatomyositis-associ ated interstitial lung disease (ARS-ILD) has a good prognosis, with few cases progressing to respiratory failure. This study aimed to determine factors predictive of lung function changes in patients with ARS-ILD.

METHODS

We retrospectively studied 49 patients with ARS-ILD treated at Kurume University Hospital Hospital between 2000 and 2018. We followed 30 patients for more than 2 years after prednisolone (PSL) therapy, with or without calcineurin inhibitors (CNIs), evaluating clinical, physiological, computed tomography, pulmonary func tion, and serological data.

RESULTS

After treatment for 24 months, no significant differences were noted between clinical parameters and improvement in forced vital capacity (FVC), %FVC, % carbon monoxide diffusing capacity/alveolar volume (%DLCO), and %DLCO/alveolar volume. Conversely, the annual change of %FVC significantly correlated with the Medical Research Council dyspnea scale grade and %FVC at the first visit and treatment. Furthermore, the annual change of %DLCO/VA significantly correlated with the duration from the first visit to treatment initiation.

CONCLUSION

Compared with PSL monotherapy, combining PSL and CNI showed greater mitigation of %FVC decline. The time from onset of ARS-ILD to the first visit is critical for preventing a decline in lung function, and as such, patients should be monitored carefully.

Rituximab as the first-line therapy in anti-synthetase syndrome-related interstitial lung disease

Anti-synthetase syndrome (ASS) is an idiopathic inflammatory myopathy (IIM). In comparison to interstitial lung disease (ILD) in polymyositis and dermatomyositis (PM/DM), ILD in ASS is more frequent, has a more aggressive phenotype, a greater involvement of the lungs, and a more rapid onset of pulmonary symptoms. Continuous declines in predicted forced vital capacity (FVC) and dyspnea were the main features of patients who developed end-stage ILD. The severity of ASS at diagnosis dictates when and which immunosuppressant will be started. There is an experience for the usage of RTX in the first, second, and subsequent lines, as well as for reintroduction and salvage therapies. Not all ASS patients will develop severe illness and require intense immunosuppression. Some features associated with poor prognosis include older age, acute or subacute onset, lack of response to steroids, and lower baseline values for FVC and DLCO. Here we hypothesize that RTX should be the first line of treatment for high-risk ILD in ASS to preserve lung function and then maintenance therapy should be continued with the same or another drug depending on the recovery of lung function.

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.

Unmet needs and perspectives in rheumatoid arthritis-associated interstitial lung disease: A critical review

Rheumatoid arthritis (RA) is a chronic systemic autoimmune disease characterized by synovitis as the most common clinical manifestation, and interstitial lung disease (RA-ILD) represents one of the most common and potentially severe extra-articular features. Our current understanding of the mechanisms and predictors of RA-ILD is limited despite the demonstration that an early identification of progressive fibrosing forms is crucial to provide timely treatment with antifibrotic therapies. While high resolution computed tomography is the gold standard technique for the diagnosis and follow-up of RA-ILD, it has been hypothesized that serum biomarkers (including novel and rare autoantibodies), new imaging techniques such as ultrasound of the lung, or the application of innovative radiologic algorithms may help towards predicting and detecting early forms of diseases. Further, while new treatments are becoming available for idiopathic and connective tissue disease-associated forms of lung fibrosis, the treatment of RA-ILD remains anecdotal and largely unexplored. We are convinced that a better understanding of the mechanisms connecting RA with ILD in a subgroup of patients as well as the creation of adequate diagnostic pathways will be mandatory steps for a more effective management of this clinically challenging entity.

Antisynthetase syndrome-related interstitial lung disease (ASyS-ILD): longitudinal imaging findings

OBJECTIVES

Interstitial lung disease (ILD) impacts mortality in antisynthetase syndrome (ASyS). Computed tomographic (CT) patterns and evolution in ASyS ILD are not well described. We report longitudinal CT patterns in ASyS-ILD and their impact on survival.

METHODS

This is a monocentric retrospective study of 47 patients with ASyS-ILD. Longitudinal CT patterns and fibrosis severity (severity of radiographic features indicating fibrosis) were analyzed by two radiologists in consensus. The association between imaging features and survival was examined using univariate Cox regression analysis.

RESULTS

In total, 211 CT scans were analyzed with an average of 4 ± 2 CT scans/patient with a median follow-up of 79 months in 47 patients. Non-fibrotic patterns were present initially in 63.8% (n = 30) of patients, while fibrotic patterns occurred in 36.2% (n = 17). The initial non-fibrotic patterns/abnormalities resolved in 23.3% (n = 7), evolved in 6.7% (n = 2), persisted in 13.3% (n = 4), and progressed in 56.7% (n = 17), while initial fibrotic patterns persisted in 82.4% (n = 14) and progressed in 17.6% (n = 3). Radiographic progression of ILD (progression in CT pattern or increased fibrosis severity) occurred in 53.2% (n = 25) of patients. Advanced age and radiographic progression were associated with decreased survival (all p < 0.05). The presence of ground-glass opacities (GGO) and predominant lower lung distribution of abnormalities on initial CTs were associated with increased survival (all p < 0.05).

CONCLUSION

Progression occurred in 56.7% of ASyS-ILD patients presenting with non-fibrotic patterns. Fibrotic patterns tended to persist. Age and radiographic progression were associated with reduced survival while the initial presence of GGO and predominant lower lobe distribution were associated with increased survival.

KEY POINTS

• In ASyS-ILD, initial non-fibrotic patterns such as OP, cNSIP, or OP-cNSIP tended to progress to fNSIP. • Fibrotic patterns such as fNSIP or UIP in ASyS-ILD tended to persist without pattern changes. • GGO and lower lung predominance on initial CT were associated with better survival while advanced baseline age and radiographic ILD progression during follow-up were associated with decreased survival.

Immune checkpoint inhibitor-related pneumonitis with atypical radiologic features in a patient with anti-aminoacyl-tRNA synthetase antibody

A man with non-small-cell lung cancer who was negative for anti-nuclear antibodies was admitted for dyspnea after immune checkpoint inhibitor (ICI) administration. Computed tomography (CT) showed complexed radiologic features, including subpleural and basal predominant reticular shadow with cystic structures and peribronchovascular consolidation. Although we treated him with high-dose steroid under a diagnosis of ICI-related pneumonitis, he developed acute exacerbation of pneumonitis with progressive fibrosis and volume loss. A re-evaluation identified anti-aminoacyl-tRNA synthetase antibody in the serum collected before ICI administration. This case highlights the importance of re-evaluating pre-existing autoimmune disorders in patients who develop ICI-related pneumonitis with atypical radiologic features.

Imaging of Lung Disease Associated with Connective Tissue Disease

There is a well-known association between the connective tissue disorders (CTDs) and lung disease. In addition to interstitial lung disease, the CTDs may affect the air spaces and pulmonary vasculature. Imaging tests are important not only in diagnosis but also in management of these complex disorders. In the present review, key aspects of the imaging of CTD-reated diseases are discussed.

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.

Severe digital ischemia as an unrecognized manifestation in patients with antisynthetase autoantibodies: Case series and systematic literature review

Objective

Severe digital ischemia, including digital ulcers and gangrene, is considered rare in patients with antisynthetase antibodies. This study aimed to elucidate the clinical features of antisynthetase-positive patients complicated with digital ulcers and/or gangrene using a systematic literature review and case series in a single-center cohort.

Methods

A systematic literature review was conducted to identify reports describing antisynthetase-positive cases with digital ulcers and/or gangrene. Our cohort of consecutive patients with antisynthetase antibodies was stratified by the history of severe digital ischemia. Demographic and clinical features and outcomes in patients with severe digital ischemia identified in the systematic literature review and our cohort were compared with those in patients without severe digital ischemia in our cohort.

Results

The systematic literature review revealed 12 antisynthetase-positive patients with severe digital ischemia from one case series and eight case reports. Seven (7%) of 100 patients with antisynthetase antibodies in our cohort had a record of severe digital ischemia. Severe digital ischemia was often found at presentation and was associated with the classification of systemic sclerosis with or without myositis overlap. Clinical features associated with severe digital ischemia in antisynthetase-positive patients included Raynaud's phenomenon (p < 0.001), digital pitting scars (p = 0.001), and nailfold capillary abnormality (p = 0.02). Outcomes of severe digital ischemia were generally favorable with vasodilators.

Conclusion

Severe digital ischemia is an overlooked complication in antisynthetase-positive patients. Antisynthetase antibodies should be measured in patients presenting with digital ulcers or gangrene, especially in those with systemic sclerosis phenotype and features associated with antisynthetase antibodies in the absence of systemic sclerosis-specific autoantibodies.

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.

18F-FDG PET/CT and HRCT: a combined tool for risk stratification in idiopathic inflammatory myopathy-associated interstitial lung disease

OBJECTIVES

Rapidly progressive interstitial lung disease (RP-ILD) is a life-threatening form of idiopathic inflammatory myopathy (IIM)-associated interstitial lung disease (ILD). We aimed to assess the combination of ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography-computed tomography (PET/CT) and high-resolution computed tomography (HRCT) for the quantification of IIM-ILD activity and risk stratification for RP-ILD.

METHOD

Patients with IIM and undergoing ¹⁸F-FDG PET/CT were included in this retrospective study. Pulmonary FDG uptake was assessed using the maximum standardized uptake value (SUV_lung) and visual score (PET score). HRCT was evaluated using visual analysis (HRCT score). Multivariable logistic regression was used to identify risk factors for RP-ILD.

RESULTS

Seventy-three patients with IIM (17 with RP-ILD, 38 with non-RP-ILD, and 18 without ILD) were included. SUV_lung, PET score, and HRCT score were significantly higher in RP-ILD than in non-RP-ILD. Strong positive correlations were observed between SUV_lung, PET score, and the HRCT parameters. The area under the curve (AUC) of the PET score to differentiate between RP-ILD and non-RP-ILD (AUC = 0.860) was higher than that of the SUV_lung (AUC = 0.802) and HRCT scores (AUC = 0.806). We developed a risk score based on the number of positive risk factors (PET score > 18, HRCT score > 140, and positive anti-melanoma differentiation-associated gene 5 (MDA5) antibody) to differentiate between RP-ILD and non-RP-ILD (AUC = 0.955). Patients with higher risk scores had significantly worse prognoses.

CONCLUSIONS

¹⁸F-FDG PET/CT is useful for assessing disease activity in patients with IIM-ILD. The combination of PET score, HRCT score, and anti-MDA5 antibody can be used to identify patients at increased risk of RP-ILD and with poor prognoses.

Clinical experience in anti-synthetase syndrome: a monocentric retrospective analytical study

OBJECTIVES: Anti-synthetase syndrome (ASS) is a rare autoimmune disorder combining autoantibodies and specific clinical manifestations. One of the particularities of ASS is the pleiomorphic radiological presentation seen at the initial work-up. Evaluating treatment response can also be challenging and requires specific clinical, functional, biological and radiological monitoring. For these reasons, it is fundamental to identify specific radiological and clinical features of ASS for improved diagnosis and therapeutic approaches.METHODS: We retrospectively studied all patients suffering from ASS in the CHU of Liège from 2008 to 2019. We analysed the clinical features, pulmonary function tests (PFTs), computed tomography (CT), and longitudinal evolution with regard to patient treatment.RESULTS: In the whole cohort of 30 patients, we identified 19 with anti-JO1 antibodies, 5 with anti-PL12 antibodies and 6 with anti-PL7 antibodies. The sex ratio was slightly in favour of males. Interestingly, PL-12 syndrome was more likely to be present in younger patients than those associated with other antibodies. Overall, 77% of the overall cohort exhibited specific pulmonary involvement without any significant difference with regard to the severity assessed by PFT at diagnosis. In contrast, the radiological presentation was pleomorphic for anti-JO1 syndrome, and anti-PL12 syndrome exhibited mainly ground-glass opacities (GGOs) and reticular abnormalities, while those with anti-PL7 antibodies showed reticulations and bronchiectasis. Longitudinal CT analysis mainly showed a reduction in consolidations and GGOs with specific therapies.CONCLUSION: In our single-centre retrospective study, we found different profiles for different autoantibodies according to age and radiological appearance.

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.

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.

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

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

2020 guide for the diagnosis and treatment of interstitial lung disease associated with connective tissue disease

The prognosis of patients with connective tissue disease (CTD) has improved significantly in recent years, but interstitial lung disease (ILD) associated with connective tissue disease (CTD-ILD) remains a refractory condition, which is a leading cause of mortality. Because it is an important prognostic factor, many observational and interventional studies have been conducted to date. However, CTD is a heterogeneous group of conditions, which makes the clinical course, treatment responses, and prognosis of CTD-ILD extremely diverse. To summarize the current understanding and unsolved questions, the Japanese Respiratory Society and the Japan College of Rheumatology collaborated to publish the world's first guide focusing on CTD-ILD, based on the evidence and expert consensus of pulmonologists and rheumatologists, along with radiologists, pathologists, and dermatologists. The task force members proposed a total of 27 items, including 7 for general topics, 9 for disease-specific topics, 3 for complications, 4 for pharmacologic treatments, and 4 for non-pharmacologic therapies, with teams of 2-4 authors and reviewers for each item to prepare a consensus statement based on a systematic literature review. Subsequently, public opinions were collected from members of both societies, and a critical review was conducted by external reviewers. Finally, the task force finalized the guide upon discussion and consensus generation. This guide is expected to contribute to the standardization of CTD-ILD medical care and is also useful as a tool for promoting future research by clarifying unresolved issues.

A narrative review of interstitial lung disease in anti-synthetase syndrome: a clinical approach

Anti-synthetase syndrome (AS) is a rare autoimmune disorder characterized by the presence of aminoacyl-transfer RNA synthetase antibodies in conjunction with clinical features such as interstitial lung disease (ILD), Raynaud's phenomenon, nonerosive arthritis, and myopathy. AS distinguishes itself from other inflammatory myopathies by its significant lung involvement and rapidly progressive interstitial lung disease (AS-ILD), therefore the management of AS-ILD requires careful clinical, serologic and radiologic assessment. Glucocorticoids are considered the mainstay of therapy; however, additional immunosuppressive agents are often required to achieve disease control. Patient prognosis is highly dependent on early diagnosis and symptom recognition as the antibody profile is thought to influence therapy response. Since progressive ILD is the leading cause of morbidity and mortality, this review will discuss the clinical approach to patient with suspected AS, with particular emphasis on diagnosis and management of AS-ILD.

Chest high-resolution computed tomography in patients with connective tissue disease: pulmonary conditions beyond "the usual suspects"

The term "connective tissue diseases" (CTDs) refers to a heterogeneous group of autoimmune disorders, including systemic sclerosis, rheumatoid arthritis, Sjögren's syndrome, systemic lupus erythematosus, polymyositis, dermatomyositis, antisynthetase syndrome, and mixed connective tissue disease. Chest high-resolution computed tomography (HRCT) is the imaging method of choice for evaluating patients with known or suspected CTD-related interstitial lung disease (CTD-ILD), a complication accounting for substantial morbidity and mortality. While specific HRCT patterns and signs of CTD-ILD have been extensively described (hence the designation "the usual suspects"), the knowledge of various, less frequent conditions involving the lungs in patients with CTD would help the radiologist produce a clinically valuable report, thus potentially influencing patient management. This paper aims to provide an up-to-date review of various unusual pulmonary CTD-related conditions the radiologist should be aware of; namely, acute exacerbation of CTD-ILD, CTD-related interstitial lung abnormalities, lung amyloidosis, MALT lymphoma, antisynthetase syndrome, pleuroparenchymal fibroelastosis-like lesion, drug-induced ILD, combined pulmonary fibrosis and emphysema, and pulmonary hypertension. For each condition, the chest HRCT appearance and the key histopathological and clinical features are resumed, helping the radiologist participate actively in the multidisciplinary discussion of complex clinical cases.

Chest computed tomography findings of adult patients with antimelanoma differentiation-associated protein 5 antibody-positive interstitial lung disease

OBJECTIVES

Interstitial lung disease (ILD) associated with the antimelanoma differentiation-associated protein 5 (anti-MDA5) antibody is a rapidly progressive disease that requires timely, aggressive treatment. However, prompt diagnosis is difficult due to the longer time required for antibody detection. This study described the computed tomography (CT) findings of anti-MDA5 antibody-positive ILD (anti-MDA5-ILD).

METHODS

CT findings of 20 patients (7 men, 13 women; mean age, 53.6 ± 13.5 years) with anti-MDA5-ILD were retrospectively reviewed. All patients had clinical diagnoses of dermatomyositis, and 14 patients presented with amyopathic findings.

RESULTS

Bilateral ground-glass attenuation, air-space consolidation, and reticular shadows were observed in 20 (100%), 15 (75%), and 3 (15%) patients, respectively. The spread of air-space consolidation was 6.0 ± 5.6% (mean ± standard deviation). Univariate analysis revealed that high Krebs von den Lungen-6, high spread of consolidation, low partial pressure of oxygen, and low forced vital capacity were significant predictors for poor survival. The final radiological diagnoses were nonspecific interstitial pneumonia and organising pneumonia (OP) in 2 (10%) and 16 (80%) patients, respectively. Further, 30% of OP patients showed fibrosis.

CONCLUSION

The characteristic CT findings of patients with anti-MDA5-ILD were ground-glass attenuation, air-space consolidation, and less reticulation. These CT findings were compatible with those of OP.

High-Resolution CT Findings of Myositis-Related Interstitial Lung Disease

Myositis-related interstitial lung disease presents with a wide variety of lesions, ranging from chronic to acute. It can be divided into two main forms by the types of onsets, namely, chronic to subacute type showing nonspecific interstitial pneumonia (NSIP) or NSIP with an organizing pneumonia (OP)/fibrosing OP (FOP) pattern and acute type showing acute lung injury (ALI) to diffuse alveolar damage (DAD) pattern. Anti-aminoacyl tRNA Synthetase antibody-positive cases mainly show an NSIP or FOP pattern, whereas anti-melanoma differentiation-associated gene 5 antibody-positive cases show ALI to DAD pattern. Bilateral consolidation with or without ground-glass opacification with lower lobe predominance is common as a major pattern in all types, but the distribution or extent is sometimes different. The early detection of findings that indicate a rapid progressive course is vital. Diffuse cranio-caudal distribution and multiple ground-glass opacifications with random distribution might indicate a poorer prognosis.

High YKL-40 serum levels and its expression in the muscle tissues of patients with antisynthetase syndrome

BACKGROUND

The protein chitinase-3-like-1 (YKL-40) is rarely analyzed in patients with myositis. Therefore, we aimed to evaluate YKL-40 serum levels; correlate them with laboratory and clinical parameters, disease status, and treatment schemes; and analyze the YKL-40 expression in the muscle tissues of patients with antisynthetase syndrome (ASSD).

METHODS

This cross-sectional single-center study included 64 adult patients with ASSD who were age-, gender-, and ethnicity-matched to 64 healthy control individuals. Their YKL-40 serum levels were analyzed using the Enzyme-Linked Immunosorbent Assay (ELISA) kit method, while YKL-40 expression in muscle tissues was analyzed using an immunohistochemical technique. Disease status was assessed using the International Myositis Assessment and Clinical Studies Group (IMACS) set scores.

RESULTS

The patients' mean age was 44.8 ± 11.8 years, and median disease duration was 1.5 (0.0-4.0) years. These patients were predominantly female (82.8%) and Caucasian (73.4%). Most patients had stable disease. The median YKL-40 serum level was significantly higher in patients with ASSD when compared to the healthy individuals: 538.4 (363.4-853.1) pg/mL versus 270.0 (201.8-451.9) pg/mL, respectively; P < 0.001. However, YKL-40 serum levels did not correlate with any clinical, laboratory, disease status, or therapeutic parameters (P > 0.050), except tumor necrosis factor alpha (TNF-α) serum levels (Spearman's correlation, rho = 0.382; P = 0.007). YKL-40 was highly expressed by inflammatory cells found in muscle biopsy specimens.

CONCLUSIONS

High YKL-40 serum levels were observed in patients with ASSD and correlated positively with TNF-α serum levels. Moreover, YKL-40 was expressed by the inflammatory cells of the muscle tissue.

Antisynthetase Syndrome Masquerading as Hypersensitivity Pneumonitis

Interstitial lung diseases (ILDs) cover a wide heterogeneous group of disorders, both of unknown and known causes. Accurate diagnosis is essential but, at the same time, presents many challenges. Typically, the distinction between idiopathic pulmonary fibrosis and fibrotic hypersensitivity pneumonitis (HP) can prove extremely difficult. However, another major, but underestimated, challenge is the diagnosis of connective tissue disease-associated ILD (CTD-ILD), specifically when ILD is the initial manifestation or when extrapulmonary manifestations are subclinical. Antisynthetase syndrome (ASyS) is a characteristic example where lung involvement can be the predominant feature in the absence of other evidence suggestive of CTD. In ASyS, lung involvement can be the initial manifestation or muscle involvement can be subclinical with normal muscle enzymes. Furthermore, a negative antinuclear antibody test does not indicate autoantibody negativity in the context of ASyS. Imaging and pathology findings in ASyS are not specific and overlap with other ILDs. Finally, bronchoalveolar lavage can exhibit pronounced lymphocytosis (>30-40%). The latter, in combination with a history of exposure to an inciting antigen, can lead to an erroneous diagnosis of HP with obvious negative impact on patients' outcome. Herein, we report 3 female patients aged 61, 65, and 70 years and 1 male patient aged 43 years, with ASyS masquerading as HP and analyze the underlying reasons of misdiagnosis, aiming to raise awareness of the need for close collaboration between pulmonologists and rheumatologists.

Myositis-Related Interstitial Lung Disease: A Respiratory Physician's Point of View

Idiopathic inflammatory myositis (IIM) is an umbrella term for diseases of unknown origin that cause muscle inflammation. Dermatomyositis and polymyositis are IIMs that commonly cause interstitial lung disease (ILD). When a patient presents with ILD, the evaluation of whether the case displays the characteristics of myositis should be determined by interview, physical examination, imaging findings, the measurement of myositis-related antibodies, and the determination of disease severity after diagnosis. Rapidly progressing anti-melanoma differentiation-associated gene 5 antibody-positive ILD may require rapid multi-drug therapy, while anti-aminoacyl tRNA synthetase (ARS) antibody-positive ILD can be treated with anti-inflammatory drugs. Importantly, however, anti-ARS antibody-positive ILD often recurs and sometimes develops into fibrosis. Early diagnosis is crucial for treatment, and we therefore need to clarify the features of myositis associated with ILD and suspect these pathologies early. This section reviews what clinicians need to look for and what findings are evaluated in patients when diagnosing myositis associated with ILD.

Single Nucleotide Polymorphism in the IL17A Gene Is Associated with Interstitial Lung Disease Positive to Anti-Jo1 Antisynthetase Autoantibodies

Antisynthetase syndrome (ASSD) is a rare multisystemic connective tissue disease affecting the skin, joints, muscles, and lungs, characterized by anti-aminoacyl transfer-RNA-synthetases (anti-tRNA) autoantibodies production, being anti-Jo1 the most frequent. We included one-hundred twenty-one ASSD patients and 340 healthy subjects (HS), and also, we divided the case group into anti-Jo1 and non-anti-Jo1. Two single nucleotide polymorphisms (SNPs) in the IL17A gene were evaluated. Anti-Jo1 was the most common anti-tRNA antibody in our cohort, and the most frequent tomographic pattern was non-specific interstitial pneumonia (NSIP). Anti-Jo1 ASSD patients had higher levels of creatine phosphokinase than the non-anti-Jo1 group. Significant differences in genotype frequencies with rs8193036/CC between anti-Jo1 vs. non-anti-Jo1 ASSD patients (p < 0.001), maintaining the association after Bonferroni correction (p = 0.002). Additionally, in the anti-Jo1 group vs. HS comparison, we found a statistically significant difference with the same SNP (p = 0.018, OR = 2.91, 95% CI = 1.15-7.35), maintaining the association after Bonferroni correction (p = 0.036). The rs8193036/CC genotype in IL17A is associated with ASSD patients with anti-Jo1. Also, anti-Jo1 and non-anti-Jo1 patients display differences in genotype frequencies.

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.

Progressive fibrosing interstitial lung diseases: A new concept and indication of nintedanib

Many interstitial lung diseases (ILDs) are characterized by chronic progressive fibrosis. The antifibrotic agents may prevent disease progression of these diseases. Nintedanib is a triple tyrosine kinase inhibitor and has an antifibrotic effect. The proven beneficial effects of nintedanib in idiopathic pulmonary fibrosis (IPF) and systemic sclerosis (SSc)-associated ILD, nintedanib was intended for use in many other fibrotic lung diseases consistent with the concept described below. With this trial, the concept and definition of progressive fibrosing ILD (PF-ILD) were created, a type of fibrosing diseases that progresses with fibrosis measured in forced vital capacity and high-resolution CT findings and worsening of respiratory symptoms at a certain rate or faster. PF-ILDs are composed of idiopathic interstial pneumonias such as non-specific interstitial pneumonia and unclassifiable interstitial pneumonia and inhalation lung diseases such as chronic hypersensitivity pneumonia and connective tissue disease-associated ILD such as rheumatoid arthritis-related ILD and SSc-related ILD and sarcoidosis and so on. Nintedanib significantly reduced the annual rate of decline in forced vital capacity over 52 weeks compared with placebo. Nintedanib received marketing approval in the United States and Japan for the treatment of PF-ILDs. This review summarizes the new concept of PF-ILDs and effectiveness of nintedanib to PF-ILDs and discussion points to be solved in the future when using nintedanib for PF-ILDs.

Interstitial lung disease in patients with antisynthetase syndrome: a retrospective case series study

PURPOSE

Antisynthetase syndrome (ASS) is a rare systemic autoimmune condition associated to the presence of anti-aminoacyl-tRNA synthetase antibodies. Interstitial lung disease (ILD) is the most prevalent manifestation of ASS and is a major determinant of morbidity and mortality. The aim of this study was to describe the radiological characteristics of patients with ASS-associated-ILD in our institution.

MATERIALS AND METHODS

Medical records from 2014 to 2020 were retrospectively reviewed and patients with a diagnosis of ASS and evidence of ILD on HRCT were included. HRCT images were reviewed by two thoracic radiologists in consensus. Five HRCT patterns were defined: cellular non-specific interstitial pneumonia (NSIP), organizing pneumonia (OP), mixed NSIP/OP pattern, acute interstitial pneumonia (AIP) pattern and fibrotic pattern. Descriptive statistics was calculated for all variables.

RESULTS

Twenty-two patients with ASS who met inclusion criteria were included. The disease presented with the typical triad of ASS in 45% of patients, 55% had ILD only at the onset. Cellular NSIP was present in 27% of patients, OP in 23%, mixed NSIP/OP in 9%, AIP in 18% and a fibrotic pattern in 23%.

CONCLUSION

HRCT findings in ASS-associated ILD are often non-specific; nevertheless, it is important to consider this diagnosis, especially in patients presenting with acute onset of symptoms.

Antisynthetase syndrome - much more than just a myopathy

The aim of the study was to summarize current knowledge on antisynthetase syndrome (ASS), including its epidemiology, pathogenesis, proposed so far diagnostic criteria, heterogeneity of clinical manifestations, prognostic factors and therapeutic possibilities. PubMed database was screened for "antisynthetase syndrome" OR "antisynthetase antibodies" between February and April 2020. Aminoacyl-tRNA synthetases participate in the immune system activation as antigens, but also serve chemoattractive and cytokine-resembling roles, initiating innate and adaptive pathways. Exposure to various inhaled antigens may induce the autoimmune cascade leading to ASS. NK cells with its impaired INF-y production as well as formation of NETs by neutrophils contribute to pathogenesis. The prevalence of symptoms vary significantly depending on the study with muscular, articular and pulmonary involvement being the most frequently observed. Although classified as subtype of idiopathic inflammatory myopathies, myositis may not necessarily be the prominent manifestation. Since clinical presentation is heterogeneous and symptoms can emerge gradually, ASS could be considered as a heterogeneous spectrum rather than a homogenous disease entity. The currently available classification criteria do not fully correspond with the clinical patterns of the disease. Therapy is based on glucocorticosteroids and other immunosuppressive agents. Randomized controlled trials, dedicated for patients with ASS, are needed to form treatment algorithms.

Influenza H1N1 virus-associated pneumonia often resembles rapidly progressive interstitial lung disease seen in collagen vascular diseases and COVID-19 pneumonia; CT-pathologic correlation in 24 patients

Purpose

To describe computed tomography (CT) findings of influenza H1N1 virus-associated pneumonia (IH1N1VAP), and to correlate CT findings to pathological ones.

Methods

The study included 24 patients with IH1N1VAP. Two observers independently evaluated the presence, distribution, and extent of CT findings. CT features were divided into either classical form (C-form) or non-classical form (NC-form). C-form included: A.) broncho-bronchiolitis and bronchopneumonia type, whereas NC-forms included: B.) diffuse peribronchovascular type, simulating subacute rheumatoid arthritis-associated (RA) interstitial lung disease (ILD) and C.) lower peripheral and/or peribronchovascular type, resembling dermatomyositis-associated ILD and COVID-19 pneumonia. In 10 cases with IH1N1VAP where lung biopsy was performed, CT and pathology findings were correlated.

Results

The most common CT findings were ground-glass opacities (24/24, 100 %) and airspace consolidation (23/24, 96 %). C-form was found in 11 (46 %) patients while NC-form in 13 (54 %). Types A, B, and C were seen in 11(46 %), 4 (17 %), and 9 (38 %) patients, respectively. The lung biopsy revealed organizing pneumonia in all patients and 6 patients (60 %) showed incorporated type organizing pneumonia that was common histological findings of rapidly progressive ILD.

Conclusion

In almost half of patients of IH1N1VAP, CT images show NC-form pneumonia pattern resembling either acute or subacute RA or dermatomyositis-associated ILD and COVID-19 pneumonia.

Genetic Susceptibility to Antisynthetase Syndrome Associated With Single-Nucleotide Variants in the IL1B Gene That Lead Variation in IL-1β Serum Levels

The antisynthetase syndrome (ASSD) is an autoimmune disorder characterized by myositis, arthritis, mechanic's hands, fever, Raynaud phenomenon, and interstitial lung disease (ILD). We aimed to evaluate single-nucleotide polymorphisms in the interleukin 1B (IL1B) gene and their association between ILD with antisynthetase autoantibodies, as well as IL-1β serum levels. The most frequent antisynthetase autoantibody was anti-Jo1. The most frequent tomographic pattern was non-specific interstitial pneumonia, whereas in the anti-Jo1 subjects, it was organized pneumonia. Anti-Jo1 patients tend to have more significant arthritis, and Raynaud phenomenon have higher levels of creatinine phosphokinase. In the IL1B gene, the GG genotype and G allele of rs1143634 [odds ratio (OR) = 2.21 and OR = 2.60, respectively, p < 0.05] are associated with an increased risk, as well as with the dominant and recessive models (p < 0.05). This finding is maintained after logistic regression analysis adjusting for potential confounding variables (p < 0.05). Subjects with the rs16944/AG heterozygous genotype had higher serum levels of IL-1β compared to homozygous (p < 0.05). In conclusion, rs1143634 is associated with a higher risk of ASSD. Also, the GA genotype is associated with higher levels of IL-1β in ASSD patients.

Antisynthetase syndrome: A distinct disease spectrum

The discovery of novel autoantibodies related to idiopathic inflammatory myopathies (collectively referred to as myositis) has not only advanced our understanding of the clinical, serological, and pathological correlation in the disease spectrum but also played a role in guiding management and prognosis. One group of the myositis-specific autoantibodies is anti-aminoacyl-tRNA synthetase (anti-ARS or anti-synthetase) which defines a syndrome with predominant interstitial lung disease, arthritis, and myositis. Autoantibodies to eight aminoacyl-tRNA synthetases have been identified with anti-Jo1 the most common in all of idiopathic inflammatory myopathies. Disease presentation and prognosis vary depending on which anti-aminoacyl-tRNA synthetase antibody is present. In this review, we will discuss the clinical characteristics, overlap features with other autoimmune diseases, prognostic factors, and management of the antisynthetase syndrome.

Pulmonary involvement in antisynthetase syndrome

PURPOSE OF REVIEW

Lung involvement is a distinctive feature of antisynthetase syndrome (ASS) and it is considered a basic disease-classifying criterion. In this review, we go over clinical features, radiological patterns, prognostic factors, pathogenesis and treatment of lung involvement in ASS patients, focusing on the clinical differences linked to the different antibody specificities known so far.

RECENT FINDINGS

The lung is the most common extramuscular organ involved in ASS and has the greatest impact on patient prognosis. The pulmonary disease-defining manifestation in ASS is interstitial lung disease (ILD), yet a proportion of patients also develop pulmonary arterial hypertension and, less frequently, obstructive bronchiolitis or acute respiratory failure according to drivers not yet fully understood but likely associated with the underlying autoantibody pattern. Clinical presentation of pulmonary involvement can range from milder forms to a rapidly progressive disease which may lead to chronic lung damage if misdiagnosed and not properly treated.

SUMMARY

The knowledge of risk factors associated with progressive or refractory lung damage is important to identify and properly treat patients with the poorest prognosis. For those with a disease not responsive to conventional therapy the efficacy of other therapeutic option is under evaluation.