Clinical features and outcomes of the patients with anti-glycyl tRNA synthetase syndrome

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.

Novel endotypes of antisynthetase syndrome identified independent of anti-aminoacyl transfer RNA synthetase antibody specificity that improve prognostic stratification

OBJECTIVES

To systemically analyse the heterogeneity in the clinical manifestations and prognoses of patients with antisynthetase syndrome (ASS) and evaluate the transcriptional signatures related to different clinical phenotypes.

METHODS

A total of 701 patients with ASS were retrospectively enrolled. The clinical presentation and prognosis were assessed in association with four anti-aminoacyl transfer RNA synthetase (ARS) antibodies: anti-Jo1, anti-PL7, anti-PL12 and anti-EJ. Unsupervised machine learning was performed for patient clustering independent of anti-ARS antibodies. Transcriptome sequencing was conducted in clustered ASS patients and healthy controls.

RESULTS

Patients with four different anti-ARS antibody subtypes demonstrated no significant differences in the incidence of rapidly progressive interstitial lung disease (RP-ILD) or prognoses. Unsupervised machine learning, independent of anti-ARS specificity, identified three endotypes with distinct clinical features and outcomes. Endotype 1 (RP-ILD cluster, 23.7%) was characterised by a high incidence of RP-ILD and a high mortality rate. Endotype 2 (dermatomyositis (DM)-like cluster, 14.5%) corresponded to patients with DM-like skin and muscle symptoms with an intermediate prognosis. Endotype 3 (arthritis cluster, 61.8%) was characterised by arthritis and mechanic's hands, with a good prognosis. Transcriptome sequencing revealed that the different endotypes had distinct gene signatures and biological processes.

CONCLUSIONS

Anti-ARS antibodies were not significant in stratifying ASS patients into subgroups with greater homogeneity in RP-ILD and prognoses. Novel ASS endotypes were identified independent of anti-ARS specificity and differed in clinical outcomes and transcriptional signatures, providing new insights into the pathogenesis of ASS.

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.

Analysis of the clinical features of antisynthetase syndrome: a retrospective cohort study in China

OBJECTIVE

To summarize the clinical, serological, and radiological characteristics of anti-synthetase syndrome (ASS) patients with different anti-aminoacyl-tRNA synthase antibody.

METHODS

Retrospective analysis was performed based on the clinical data of 88 patients diagnosed with ASS in Tianjin Medical University General Hospital from January 2015 to December 2020. The clinical data included general conditions, serological indexes, high-resolution CT (HRCT) characteristics, and pulmonary function manifestations.

RESULTS

Among the 88 patients, there were 17 males and 71 females. The anti-synthetase antibodies included anti-Jo-1 (n = 42), anti-PL-7 (n = 14), anti-PL-12 (n = 9), anti-EJ (n = 20), and anti-OJ (n = 3) antibodies. The most common clinical manifestations of ASS patients were interstitial lung disease (ILD) (90%, 79/88), followed by myositis (79.5%, 70/88), arthritis (50%, 44/88), and rash (50%, 44/88). The frequency of arthritis in the anti-Jo-1 antibody-positive group was higher than that of the anti-PL-7 and anti-EJ antibody groups (P = 0.004, P = 0.002, respectively). The frequency of Gottron's sign in the anti-PL-7 antibody positive group was higher than that of the anti-Jo-1 and anti-PL-12 antibody-positive groups (P = 0.006, P = 0.04). Isolated arthritis was the most frequent initial symptoms in anti-Jo-1 antibody-positive group (47.6%, 20/42), while isolated ILD was most frequent in patients with anti-EJ antibody (50%, 10/20), and isolated myositis in patients carrying anti-OJ (66.7%, 2/3). There were only 32 cases (36.4%) with the typical clinical triad (myositis, arthritis, ILD). In our cohort, 79 patients (90%) were complicated with ILD. Meanwhile, 7 out of 79 cases were classified into rapid progressive group with 6 cases (85.7%) carrying anti-Ro-52 antibody. The probability of reticular and honeycombing shadow in HRCT of patients with anti-EJ antibody positive was higher than that of other groups (P < 0.05).

CONCLUSION

ILD, myositis, and arthritis were the most common clinical manifestations in patients with ASS. Different antibody-positive patients have different initial symptoms. Patients with isolated arthritis, myositis, and ILD should be vigilant of ASS. The complication of anti-Ro-52 antibody in ASS patients was associated with rapidly progressive pulmonary interstitial disease. Patients with positive anti-EJ antibodies tend to have ILD as the first symptom, and with high occurrence of ILD, the HRCT showed more serious patterns, suggesting the correlation between anti-EJ antibodies and ILD. Key Points • Analyzing specific clinical manifestations in ASS patients with different ARS antibodies can raise awareness of the disease and reduce misdiagnosis. • Anti-EJ antibodies were correlated with ILD. • Anti-Ro-52 antibodies may correlate with RP-ILD in ASS patients.

An observational study of clinical recurrence in patients with interstitial lung disease related to the antisynthetase syndrome

OBJECTIVE

To describe the clinical characteristics and risk factors of clinical recurrence in interstitial lung disease related to antisynthetase syndrome (ARS-ILD).

METHODS

Patients diagnosed as ARS-ILD in Nanjing Drum Tower Hospital between January 2015 and November 2020 were retrospectively analyzed. Clinical information and treatment course were reviewed. The primary endpoint was the disease recurrence, and the secondary point was mortality. Univariate and multivariable Cox regression analyses were performed to identify risk factors for recurrence.

RESULTS

Totally, 132 patients with ARS-ILD received immunomodulation treatment from diagnosis. During follow-ups, sixty-nine patients showed recurrence, with a recurrency rate yielding 52.3%. The median duration from treatment initiation to recurrence was 11 (5-18) months. The median tapering course in the recurrence group was 8 (3-12.5) months, which was significantly shorter than the 16 (10-32) months in the no-recurrence group (p < 0.001). Fifty-eight patients experienced recurrence when the glucocorticoids (GC) dose dropped to 10 (9.375-15) mg/day. Twelve patients discontinued GC with a median treatment course of 11.5 (8-16.75) months, and 11 patients developed recurrence after discontinuing GC for 3 (1-4) months. Twelve patients died, with a mortality rate of 9.1%, and recurrence was not associated with increased mortality. The adjusted multivariate analysis showed that age, increased serum lactate dehydrogenase (LDH) level, relatively shorter tapering duration, and inappropriate GC discontinuation were associated with recurrence.

CONCLUSION

Recurrence of ARS-ILD was common during medication intensity reduction. Age, LDH, medication tapering duration, and discontinuation were risk factors for recurrence. Further efforts to reduce recurrence should take into consideration of these factors. Key Points • Recurrence is observed commonly with a recurrency rate 52.3% in patients with interstitial lung disease related to antisynthetase syndrome (ARS-ILD) when glucocorticoids (GC) tapering or discontinuation. • Age, increased serum lactate dehydrogenase (LDH) level, medication tapering duration, and GC discontinuation were identified to be significantly associated with the recurrence of ARS-ILD.

A multidisciplinary approach to the diagnosis of antisynthetase syndrome

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

Clinical features, prognostic factors, and survival of patients with antisynthetase syndrome and interstitial lung disease

Objective

This study aimed to analyze the clinical features and prognostic factors of imaging progression and survival in patients with antisynthetase syndrome (ASS) complicated by interstitial lung disease (ILD) in a large Chinese cohort.

Methods

Medical records, imaging, and serological data of 111 patients with ASS-ILD (positive for at least one of the following autoantibodies: anti-Jo1, anti-PL7, anti-PL12, and anti-EJ) from the Affiliated Yantai Yuhuangding Hospital of Qingdao University database were retrospectively investigated. According to the changes in high-resolution computed tomography (HRCT) outcomes at 1 year follow-up, Patients were categorized into three groups: the regression, stability, and deterioration groups. Univariate analysis was performed to evaluate the possible prognostic factors of ILD outcome and death, and multivariate analysis was performed to determine the independent predictors of ASS-ILD outcome and death by logistic regression.

Results

The number of CD3-CD19+ cells and initial glucocorticoid dosage were correlated with imaging progression, and may be independent risk factors for ILD deterioration. Dyspnea as the first symptom, hypohemoglobinemia, the serum ferritin level, oxygen partial pressure at diagnosis, and different treatment types were important factors affecting survival, and the initial serum ferritin level may be an independent risk factor for survival.

Conclusions

The clinical characteristics of patients with ASS-ILD with different antisynthetase antibody subtypes are different. An increase in the CD3-CD19+ cell level is an independent risk factor for the deterioration of HRCT imaging. Early intensive treatment with high-dose glucocorticoids can effectively improve imaging prognosis of ILD. Patients with significantly elevated serum ferritin levels should be treated intensively.

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

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

Immune-mediated necrotizing myopathy (IMNM): A myopathological challenge

This review is focused on the myopathological spectrum of immune mediated necrotizing myopathies (IMNMs) and its differentiation with other, potentially mimicking, inflammatory and non-inflammatory myopathies. IMNMs are a subgroup of idiopathic inflammatory myopathies (IIMs) characterized by severe clinical presentation with rapidly progressive muscular weakness and creatine kinase elevation, often requiring early aggressive immunotherapy, associated to the presence of muscle specific autoantibodies (MSA) against signal recognition particle (SRP) or 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCR). Muscle biopsy usually shows unspecific features consisting in prominent necrosis and regeneration of muscle fibres with mild or absent inflammatory infiltrates, inconstant and faint expression of major histocompatibility complex (MHC) class I and variable deposition of C5b-9 on sarcolemma. Several conditions could present similar histopathological findings leading to possible misdiagnosis of IMNM with other IIMs or non-inflammatory myopathies (nIMs) and viceversa. This review analyses the muscle biopsy data in IMNMs through a systematic revision of the literature from the last five decades. Several histopathological variables have been considered in both SRP- and HMGCR-IMNM, and compared to other IIMs - as dermatomyositis (DM) and anti-synthethase syndrome (ASS) - or other nIMs -as toxic myopathies (TM), critical illness myopathy (CIM) and muscular dystrophy (MD) - to elucidate similarities and differences among these potentially mimicking conditions. The major histopathological findings of IMNMs were: very frequent necrosis and regeneration of muscle fibres (93%), mild inflammatory component mainly constituted by scattered isolated (65%) CD68-prevalent (68%) cells, without CD8 invading/surrounding non-necrotic fibres, variable expression of MHC-I in non-necrotic fibres (56%) and constant expression of sarcoplasmic p62, confirming those that are widely considered the major histological characteristics of IMNMs. Conversely, only 42% of biopsies showed a sarcolemmal deposition of C5b-9 component. Few differences between SRP and HMGCR IMNMs consisted in more severe necrosis and regeneration in SRP than in HMGCR (p = 0.01); more frequent inflammatory infiltrates (p = 0.007) with perivascular localization (p = 0.01) and clustered expression of MHC-I (p = 0.007) in HMGCR; very low expression of sarcolemmal C5b-9 in SRP (18%) compared to HMGCR (56%) (p = 0.0001). Milder necrosis and regeneration, detection of perifascicular pathology, presence of lymphocytic inflammatory infiltrates and myofibre expression of MxA help to distinguish DM or ASS from IMNM. nIMs can present signs of inflammation at muscle biopsy. Low fibre size variability with overexpression of both MHC-I and II, associated with C5b-9 deposition, could could be observed in CIM, while increased connective tissue should lead to consider MD, or TM in absence of C5b-9 deposition. Nevertheless, these features are not constantly detected and muscle biopsy could not be diriment. For this reason, muscle biopsy should always be critically considered in light of the clinical context before concluding for a definite diagnosis of IMNM, only based on histopathological findings. More rigorous collection and analysis of muscle biopsy is warranted to obtain a higher quality and more homogeneous histopathological data in inflammatory myopathies.

Description and Analysis of a Novel Subtype of the Anti-Synthetase Syndrome Characterized by Frequent Attacks of Fever and Systemic Inflammation in a Single-Center Cohort Study

Objectives

The aim of this study was to investigate anti-synthetase syndrome (ASyS) patients who presented with recurrent episodes of fever and systemic inflammation.

Methods

A retrospective cohort of Chinese ASyS patients (n=126) in our center (between January 2013 and January 2020) was included. Patients presenting with concomitant autoimmune rheumatic diseases or malignancies were subsequently excluded. The number of non-infectious fever attacks and attack frequency were recorded and calculated. Patients with two or more attacks and within the upper three quartiles of attack frequency were defined as high-inflammation group. Univariate and multivariate analyses were carried out to characterize the high-inflammation subtype.

Results

Out of 113 eligible patients with an average of 5 years follow up, 25 patients were defined as the high-inflammation group (16 for anti-Jo1, 9 for anti-PL7), with an average of 1.12 attack/patient-year. Compared to low-inflammation group (0-1 attack only and a frequency lower than 0.5 attack/patient-year), the high-inflammation group had higher occurrence of fever and rapid progressive interstitial lung disease (RPILD) as the first presentation (84% vs. 21% and 40% vs. 9%, respectively, both p<0.01). Anti-PL-7 was related to the more inflammatory phenotype (p=0.014). Cumulative disease-modifying agent exposures (>=3) were much higher in the high-inflammation group (60% vs. 26%), while biological agents, i.e., rituximab and tocilizumab, showed better "drug survival" for Jo-1+ and PL-7+ ASyS patients with high inflammation, respectively, in our cohort.

Conclusions

ASyS with recurrent systemic inflammatory episodes reflects a subtype of more aggressive and refractory disease in the spectrum of ASyS. Increased awareness of this subtype might lead to more appropriate management.

Myositis specific antibodies are associated with isolated anti-Ro-52 associated interstitial lung disease

OBJECTIVES

Anti-Ro-52 antibody positivity might be associated with the presence of interstitial lung disease (ILD) among patients with autoimmune features. However, the clinical significance of isolated anti-Ro-52 positivity (i.e., the presence of anti-Ro52 antibodies but the absence of anti-Ro60 antibodies; anti-Ro52+-Ro60-) in patients with ILD is not clear.

METHODS

This is a prospective and observational study of Chinese ILD patients with isolated anti-Ro-52 positivity. According to their myositis-specific antibody (MSA) status, patients were split into groups, and their clinical and radiological features were compared.

RESULTS

Of the 158 enrolled patients with ILD and isolated anti-Ro-52 positivity (isolated anti-Ro-52-ILD), there were 130 patients with a positive MSA status and 28 patients with a negative MSA status. Anti-synthetase antibodies (ASAs) were found in 61.5% of patients with MSA+ ILD, and anti-melanoma differentiated-associated protein 5 (MDA-5) antibodies were found in the remaining 38.5% of patients. The anti-nuclear antibody (ANA) pattern was associated with ASA and anti-MDA-5 positivity (χ2=70.7, P < 0.001; Cramer's value 0.47, P < 0.001): ANA negativity was associated with anti-MDA-5 positivity, and cytoplasmic ANA positivity was associated with ASA positivity. There were statistically significant differences in the high-resolution CT patterns between patients with isolated anti-Ro-52 positivity with different MSA statuses (χ2=29.8, P < 0.001; Cramer's value 0.31, P < 0.001): OP pattern was more common in patients with anti-MDA-5 antibodies than in those without anti-MDA-5 antibodies.

CONCLUSIONS

Patients with isolated anti-Ro-52-ILD showed high positivity of MSA. Isolated anti-Ro-52 positivity with cytoplasmic ANA positivity was strongly associated with ASA+-ILD, while ANA negativity was associated with anti-MDA-5+-ILD.

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.