Abstract
Background
Antisynthetase syndrome (ASyS) is an idiopathic inflammatory myopathy characterized by interstitial lung disease (ILD), mechanic’s hands, fever, arthritis, and Raynaud’s phenomenon. Although several domestic and international reports have described the clinical manifestations of ASyS, regional differences in clinical characteristics, including skin involvement, remain poorly understood. This study aimed to compare the regional differences in clinical features of ASyS by comparing data of Japanese patients with ASyS with those of previously published cohorts.
Methods
We conducted a retrospective chart review of 48 patients with ASyS at Yokohama City University Hospital between 2010 and 2024 and compared their data with those of previously published cohorts using univariate analysis. A literature review was performed using the PubMed database, with the search results limited to articles published between January 2010 and December 2024.
Results
The mean age at onset was 56.5 ± 14.0 years, with a male-to-female ratio of 13:35. The prevalence of anti-Jo1 antibody was 35%. ILD and muscle weakness were observed in 97% and 52% of the patients, respectively. The most frequent skin involvement was Gottron’s sign (73%), followed by mechanic’s hands (65%) and periungual erythema (40%). A literature review using the same ASyS diagnostic criteria revealed that Asian cohorts, including ours, tend to have higher rates of ILD complications and a lower prevalence of anti-Jo1 antibodies than European cohorts. Furthermore, in the comparison of clinical manifestations with other Japanese and Asian cohorts, the rates of Raynaud’s phenomenon, muscle weakness, and malignant complications were nearly identical, although slight differences were observed in skin manifestations. By contrast, the European cohort was characterized by a high frequency of Raynaud’s phenomenon (39%), muscle weakness (85%), and anti-Jo1 antibody positivity (83%); meanwhile, ILD and mechanic’s hands were observed in 68% and 31%, respectively.
Conclusions
These results suggest that regional differences may exist in the clinical manifestations of ASyS, particularly in ILD prevalence, which may be linked to the underlying distribution of anti-aminoacyl transfer RNA synthetase antibody subtypes. A more detailed profiling of each antisynthetase antibody in a larger population is warranted to clarify these differences.
Keywords: Antisynthetase syndrome, Antisynthetase antibody, Cohort study, Clinical manifestation, Regional difference
Background
Antisynthetase syndrome (ASyS) is a systemic autoimmune disorder classified within the idiopathic inflammatory myopathies (IIMs), which includes polymyositis (PM), dermatomyositis (DM), and immune-mediated necrotizing myopathy [1]. Among patients with IIMs, anti-aminoacyl transfer RNA synthetase (ARS) antibodies, which are myositis-specific autoantibodies (MSAs), such as anti-Jo1, anti-PL-7, anti-PL-12, anti-EJ, anti-OJ, anti-KS, anti-Zo, and anti-Ha antibodies, are detected in 20–30% of cases [2]. The clinical manifestations of ASyS are characterized by a high frequency of interstitial lung disease (ILD), mechanic’s hands, fever, arthritis, and Raynaud’s phenomenon [3, 4]. However, ASyS lacks unified classification criteria, and methods for the detection of antibodies vary by country and region, creating challenges for consistent diagnosis and research. In addition, the clinical features of ASyS vary depending on the specific anti-ARS antibodies present. To elucidate these differences, cluster analyses have identified three clinically distinct phenotypes among patients with ASyS: one defined by ILD with autoimmune features/amyopathic DM; a second characterized by older age at diagnosis and a higher frequency of malignancy; and a third by younger age at diagnosis with a high prevalence of myositis, arthritis, DM pathognomonic skin involvement, mechanic’s hands, and fever [5]. Furthermore, in 2024, the international multi-center “Classification Criteria for Antisynthetase Syndrome (CLASS)” project analyzed a large database and identified specific clinical and serological variables associated with ASyS. These include arthritis, muscle involvement (diffuse myalgia, muscle weakness, and muscle enzyme elevation), ILD, mechanic’s hands, secondary pulmonary hypertension due to ILD, Raynaud phenomenon, and unexplained fever [6].
The prevalence of MSAs in DM can differ between children and adults, and patients with the same antibodies may present with different clinical manifestations [7]. Moreover, the prevalence of certain MSAs, such as anti-MDA5 antibody, has been reported to vary by region [8, 9]. However, potential regional differences in the clinical characteristics of ASyS remain poorly understood.
Therefore, we retrospectively investigated the clinical characteristics of patients with ASyS in a Japanese cohort and compared these findings with those of previously published cohorts to determine whether regional differences exist.
Methods
Patients
Data were collected from a retrospective chart review of Japanese patients diagnosed with ASyS at Yokohama City University Hospital between January 2010 and July 2024. Patients with ASyS fulfilled the diagnostic criteria proposed by Connors et al. [10] or the 2017 European League Against Rheumatism (EULAR)/American College of Rheumatology (ACR) Classification Criteria of IIMs [11]. This study was approved by the Institutional Review Board of Yokohama City University (approval No: B190800045).
Clinical and biologic data
Clinical and laboratory data were obtained from the medical records at the time of diagnosis and throughout the disease course. The collected data included age, sex, laboratory data, autoantibody status, age at ASyS onset, muscle weakness, dysphagia, ASyS-related skin involvement (Gottron’s papules, Gottron’s sign, heliotrope rash, mechanic’s hands, nailfold erythema, nailfold capillary abnormalities, shawl sign, V-neck sign, auricular erythema, clubbed finger, flagellate erythema, chilblains, palmar papules, and poikiloderma), Raynaud’s phenomenon, malignancy, fever, and ILD.
In addition to meeting the criteria proposed by Connors, the patients were clinically characterized into four phenotypic groups, in accordance with previous literature [5]: DM meeting the “definite” or “probable” diagnostic criteria by Bohan and Peter [12]; clinically amyopathic DM (CADM) meeting Sontheimer’s proposed criteria [13]; PM meeting the 2017 EULAR/ACR Classification Criteria [11]; and interstitial pneumonia with autoimmune features (IPAF) meeting the diagnostic criteria proposed by Fischer [14]. IPAF represents a classification of interstitial pneumonia with autoimmune features within the spectrum of idiopathic interstitial pneumonia, and anti-ARS antibody-positive IPAF may conceptually overlap with ASyS. ILD was defined as bilateral reticular opacity, the presence of consolidation, ground-glass opacity, and/or a honeycomb appearance on high-resolution chest computed tomography.
Anti-ARS and anti-Jo1 antibodies were detected using MESACUP™ anti-ARS tests and STACIA MEBLux test Jo1, respectively (MBL, Nagoya, Japan). ASyS-associated malignancy was defined as any malignancy observed within 3 years before or after the onset of ASyS [15]. Nailfold capillary abnormalities were detected using nailfold video capillaroscopy (TOKU Capillaro; Toku Corporation, Tokyo, Japan).
Literature review
A literature review was performed using the PubMed database. The search strategy combined Medical Subject Headings (MeSH) and free-text terms as follows: (“antisynthetase syndrome” OR “anti-synthetase syndrome” OR “anti-ARS antibody” OR “anti-aminoacyl tRNA synthetase antibody”) AND (cohort OR “cohort study” OR “observational study”). The search was limited to articles published between January 2010 and December 2024. Reference lists of relevant articles were also reviewed to identify additional studies. Studies were included if they: (1) reported clinical characteristics of patients with ASyS, (2) included ≥ 50 patients (relatively large cohort), and (3) fulfilled either the Connors diagnostic criteria [10], or the 2017 EULAR/ACR classification criteria [11].
Statistical analysis
Continuous and normally distributed variables are expressed as mean ± standard deviation. Nonparametric continuous variables are expressed as medians with interquartile ranges. In this study, there was no missing data. Fisher’s exact, Mann–Whitney U, and Wilcoxon tests were used for statistical analysis, as appropriate. All statistical analyses were conducted using the GraphPad Prism version 8.2 software (GraphPad Software, San Diego, CA, USA).
Results
Baseline patient profiles
A total of 48 patients with ASyS were included in the study. All 48 patients met the diagnostic criteria proposed by Connors et al. [10], while 35 met the 2017 EULAR/ACR Classification Criteria (“definite” or “probable”) [11] (Fig. 1). Baseline clinical characteristics of the patients are shown in Table 1. The median age was 54.0 (IQR, 46.0–67.0) years. The patients were clinically characterized into four clinical phenotypic groups: DM (20 patients [42%]), CADM (16 patients [33%]), PM (one patient [2%], and IPAF (11 patients [23%]). Among them, the anti-Jo1 antibody was positive in 35% (17 patients). ILD was found at a high frequency of 98% (47 patients), and ASyS-associated malignancy was found in 13% (6 patients) of the patients. The most frequent skin involvements were Gottron’s sign (73%), followed by mechanic’s hands (65%), periungual erythema (40%), nailfold capillary abnormalities (31%), shawl sign (21%), and heliotrope rash (19%). A comparison between males and females showed that the clinical phenotype DM was significantly more prevalent in females (P = 0.046), whereas CADM was significantly more common in males (P = 0.018). With respect to skin involvement, heliotrope rash (P = 0.048) was more common in males than in females.
Fig. 1.
Flowchart of study design. Flowchart showing patients who fulfilled the diagnostic criteria proposed by Connors et al. or the 2017 EULAR/ACR Classification Criteria of IIMs (“definite” or “probable”). IIMs, idiopathic inflammatory myopathies
Table 1.
Clinical characteristics of 48 patients with ASyS
| Variable | Total (n = 48) |
Male (n = 13) |
Female (n = 35) |
P value Male vs. female |
|---|---|---|---|---|
|
Age at onset (years), median (IQR) |
54.0 (46.0–67.0) |
49.0 (46.0–64.0) |
54.0 (47.5–69.0) |
0.547 |
| Clinical phenotype | ||||
| DM | 20 (42) | 2 (15) | 18 (51) | 0.046 |
| CADM | 16 (33) | 8 (62) | 8 (23) | 0.018 |
| PM | 1 (2) | 0 (0) | 1 (3) | 1.000 |
| IPAF | 11 (23) | 3 (23) | 8 (23) | 1.000 |
| The type of autoantibody | ||||
| Anti-Jo1 antibody positive | 17 (35) | 3 (23) | 14 (40) | 0.330 |
| Anti-SS-A antibody positive | 14 (29) | 2 (15) | 12 (34) | 0.292 |
| Fever | 9 (19) | 1 (8) | 6 (17) | 0.687 |
| ILD | 47 (98) | 13 (100) | 34 (97) | 1.000 |
| Raynaud’s phenomenon | 6 (13) | 0 (0) | 6 (17) | 0.171 |
| Malignancy | 6 (13) | 1 (8) | 5 (14) | 1.000 |
| Breast cancer | 2 (4) | 0 (0) | 2 (6) | |
| Lung cancer | 1 (2) | 0 (0) | 1 (3) | |
| Renal cancer | 1 (2) | 0 (0) | 1 (3) | |
| Skin cancer | 1 (2) | 0 (0) | 1 (3) | |
| Prostate cancer | 1 (2) | 1 (8) | 0 (0) | |
| Muscle involvement, n (%) | ||||
| Muscle weakness | 25 (52) | 7 (54) | 18 (51) | 1.000 |
| Dysphagia | 0 (0) | 0 (0) | 0 (0) | 1.000 |
| Skin involvement, n (%) | ||||
| Gottron’s sign | 35 (73) | 10 (77) | 25 (71) | 1.000 |
| Mechanic’s hands | 31 (65) | 8 (62) | 23 (66) | 1.000 |
| Nailfold erythema | 19 (40) | 5 (38) | 14 (40) | 1.000 |
| Nailfold capillary abnormalities | 15 (31) | 1 (8) | 12 (34) | 0.721 |
| Shawl sign | 10 (21) | 1 (8) | 9 (26) | 0.248 |
| Heliotrope rash | 9 (19) | 5 (38) | 4 (11) | 0.048 |
| Gottron’s papules | 8 (17) | 4 (31) | 4 (11) | 0.187 |
| V-neck sign | 6 (13) | 1 (8) | 5 (14) | 1.000 |
| Auricular erythema | 4 (8) | 1 (8) | 3 (9) | 1.000 |
| Clubbed finger | 3 (6) | 2 (15) | 1 (3) | 0.174 |
| Flagellate erythema | 2 (4) | 2 (15) | 0 (0) | 0.069 |
| Chilblains | 2 (4) | 0 (0) | 2 (6) | 1.000 |
| Palmar papule | 1 (1) | 0 (0) | 1 (3) | 1.000 |
| Poikiloderma | 1 (1) | 0 (0) | 1 (3) | 1.000 |
| Outcome | ||||
| Dead | 3 (6) | 0 (0) | 3 (9) | 0.553 |
IQR Interquartile range, ILD Interstitial lung disease, ASyS Antisynthetase syndrome, DM Dermatomyositis, ADM Amyopathic dermatomyositis, PM Polymyositis, IPAF Interstitial pneumonia with autoimmune feature
Differences in ILD prevalences and anti-Jo1 antibody positivity rates by region or country
We first investigated the regional differences in the prevalence of ILD and anti-Jo1 antibody positivity in patients with ASyS. To enable comparisons across regions, we extracted data of published cohorts that met the same criteria as our cohort and summarized them in Table 2 [16–21]. These reports were categorized into two: those from Asia (Japan, China, and Thailand) and Europe (multi-center cohorts in several European countries, Portugal, and Sweden). Interestingly, the Asian cohort, excluding one from Thailand (78%), exhibited ILD prevalence rates > 90%, whereas European cohorts showed a lower incidence, ranging from 69% to 80%. Indeed, a combined comparison of these cohorts showed that the incidence of ILD in patients with ASyS tends to be higher in Asia than in Europe. By contrast, all cohorts from the Asian region reported anti-Jo1 antibody positivity rates below 50% (27–50%), while European regions showed high rates ranging from 61 to 90%. Published data suggested that anti-Jo1 antibody positivity tends to be lower in Asian cohorts compared with European cohorts. Interestingly, the anti-Jo1 antibody positivity rate in the CLASS project, an international cohort, was 57%, falling between the average rates observed in Asian and European regions [6]. These results indicate significant regional differences in the clinical manifestations of ASyS, particularly regarding ILD prevalence and anti-Jo1 antibody positivity.
Table 2.
Region or country-wise ILD complication and anti-Jo1 antibody positivity rates among patients with ASyS
| Asian cohort | European cohort | ||||||||
|---|---|---|---|---|---|---|---|---|---|
| Our cohort | Sodsri et al. [16] |
Zhang et al. [17] |
Wang et al. [18] |
Hum et al. [19] |
Preger et al. [20] |
Martins et al. [21] |
Asia Total |
Europe Total |
|
| Year | 2025 | 2023 | 2023 | 2022 | 2024 | 2023 | 2022 | ||
| Country or region | Japan | Thailand | China | China | Europe | Sweden | Portugal | ||
| Race | Asian 100% | ND | Asian 100% | Asian 100% | ND | White 98% | ND | ||
| Sample size, n | 48 | 82 | 119 | 88 | 649 | 50 | 70 | 337 | 769 |
|
ASyS with ILD, n (%) |
47 (98) |
64 (78) |
111 (93) |
79 (90) |
441 (68) |
39 (80) |
53 (76) |
301 (89) |
533 (69) |
| ASyS with anti-Jo1 antibody, n (%) |
17 (35) |
22 (27) |
59 (50) |
42 (48) |
541 (83) |
45 (90) |
43 (61) |
140 (42) |
629 (82) |
ILD Interstitial lung disease, ASyS Antisynthetase syndrome, ND no data
Comparison of clinical manifestations between our cohort and Asian cohorts
To investigate the regional differences in the clinical manifestations of ASyS in detail, we first compared our cohort with previously reported Asian cohorts. For this comparison, we selected well-characterized cohorts from the Asian region that provided detailed descriptions of clinical features to minimize selection bias (Table 3). The mean age at onset; sex ratio; and prevalences of ILD, anti-Jo1 antibody positivity, Raynaud’s phenomenon, muscle weakness, and malignancy complications were nearly identical between our cohort and two large Japanese cohorts [4, 22]. Meanwhile, slight differences were observed in skin manifestations. The percentage of heliotrope rash was almost identical among the three cohorts; however, Gottron’s sign and mechanic’s hands were more prevalent in our cohort than in the other two Japanese cohorts. We then extended the comparison to other cohorts from the broader Asian region [17, 23]. The results were similar to those of the Japanese cohort comparison. Regarding skin manifestations, the prevalence of heliotrope rash remained comparable. Mechanic’s hands and shawl sign were frequently found in our cohort, whereas Gottron’s papules were predominant in the Asian cohort [23] (Table 3). Overall, these results suggest that, while minor variations in skin manifestations exist among Asian cohorts, other key clinical features of ASyS are generally consistent across the region.
Table 3.
Comparison of ASyS clinical manifestations between our cohort and Asian cohorts
| Variable | Japan | China | |||
|---|---|---|---|---|---|
| Our cohort | Hamaguchi et al. [22] |
Yamamoto et al. [5] |
Zhang et al. [17] |
Shi et al. [23] |
|
| Number of cases, n | 48 | 165 | 125 | 119 | 124 |
| Female, n (%) | 35 (73) | 130 (79) | 92 (74) | 88 (74) | 94 (76) |
|
Age at onset (years), mean (range) |
56.5 (27–87) |
53 (18–79) |
57.5 (45–68) |
54 [50–60] |
50.4 (mean) |
| Anti-Jo1 antibody positive, n (%) | 17 (35) | 59 (36) | 34 (27) | 59 (50) | 62 (50) |
| ILD, n (%) | 47 (98) | 155 (94) | 125 (100) | 111 (93) | 117 (94) |
| Raynaud’s phenomenon, n (%) | 6 (13) | 40 (24) | 17 (23) | 18 (15) | 12 (10) |
| Malignancy, n (%) | 6 (13) | 19 (12) | 5 (4) | - | 8 (7) |
| Muscle weakness, n (%) | 25 (52) | 95 (58) | 82 (66) | 53 (45) | 79 (64) |
| Skin involvement, n (%) | |||||
| Gottron’s sign (hand) | 23 (48) | 63 (38) | - | - | - |
| Gottron’s sign (elbow and/or knee) | 25 (52) | 51 (31) | - | - | - |
| Gottron’s sign | 35 (73) | - | 23 (18) | - | - |
| Gottron’s papules | 8 (17) | - | 50 (40) | 20 (17) | 55 (44) |
| Heliotrope rash | 9 (19) | 26 (16) | 33 (17) | 9 (19) | 0.485 |
| Mechanic’s hands | 31 (65) | 67 (41) | 64 (50) | 67 (56) | 57 (46) |
| Shawl sign | 10 (21) | - | - | 7 (6) | - |
| V-neck sign | 6 (13) | - | - | 10 (8) | - |
ILD Interstitial lung disease
Comparisons of clinical manifestations between our cohort and the European cohort
To further explore regional differences in the clinical characteristics of ASyS, we showed the clinical characteristics of our cohort and the European ASyS cohort (Table 4) [19]. Several clinical differences were observed between the two cohorts. The European cohort was characterized by a high frequency of Raynaud’s phenomenon (39%), muscle weakness (85%), and anti-Jo1 antibody positivity (83%), whereas ILD and mechanic’s hands were observed in 68% and 31%, respectively. Regarding skin manifestations in the European cohort, the reported frequencies were 22% for Gottron’s sign, 17% for nailfold erythema, 3% for shawl sign, and 4% for V-neck sign. These results indicate that the frequencies of organ involvement and skin manifestations differ markedly between Asian and European cohorts, even among patients with the same ASyS diagnosis.
Table 4.
Comparison of ASyS clinical manifestations between our cohort and European cohorts
| Variable | Our cohort | Hum et al. [19] |
|---|---|---|
| Number of cases | 48 | 649 |
| Female | 35 (73) | 425 (65) |
| Age at onset (years), median (IQR) | 54.0 (46.0–67.0) | 49 (36–60) |
| Anti-Jo1 antibody positive | 17 (35) | 541 (83) |
| ILD | 47 (98) | 441 (68) |
| Raynaud’s phenomenon | 6 (13) | 252 (39) |
| Malignancy | 6 (13) | 21 (3) |
| Muscle weakness | 25 (52) | 549 (85) |
| Skin involvement, n (%) | ||
| Gottron’s sign | 35 (73) | 141 (22) |
| Heliotrope rash | 9 (19) | 90 (14) |
| Mechanic’s hands | 31 (65) | 200 (31) |
| Nailfold erythema | 19 (40) | 110 (17) |
| Shawl sign | 10 (21) | 18 (3) |
| V-neck sign | 6 (13) | 28 (4) |
| Calcification | 0 (0) | 13 (2) |
| Skin ulcer | 0 (0) | 8 (1) |
ILD Interstitial lung disease, IQR Interquartile range
Discussion
This study examined the clinical manifestations of ASyS in a single-institution cohort and explored the regional differences in clinical characteristics. To date, the definition of ASyS has remained vague and broad; therefore, in this study, the same criteria were used for the eligible cohort for comparison. Interestingly, ILD complication rates in the Asian region were higher than those in the European region. By contrast, anti-Jo1 antibody positivity tended to be higher in the European cohorts than in the Asian cohorts. Furthermore, some regional differences were observed in muscle weakness and skin manifestations, such as Raynaud’s phenomenon. These differences may be influenced by multiple factors such as racial or regional variations in the prevalence of specific anti-ARS antibodies and human leukocyte antigen (HLA) genotypes.
The CLASS project identified several key clinical manifestations associated with ASyS diagnosis [6]. This project provided extensive international coverage of real-world data, resulting in reduced selection bias, which is common in small cohort studies. While these data are extremely useful for future diagnosis and clinical characterization of ASyS, the large amount of data across 30 countries may make it difficult to identify regional and racial differences. Indeed, a meta-analysis revealed that the global prevalence of ILD in patients with PM/DM is approximately 41%, with a higher prevalence in Asia than in North America and Europe [24]. In the analysis for each MSA, although the studies were limited by the small sample size due to the small population of juvenile anti-MDA5 antibody-positive DM, there were racial or regional differences as well; for example, the complication rate of ILD was as high as 80.6% in the Japanese cohort, but as low as 19% in the UK cohort and 25.7% in the North American cohort [9, 25, 26]. These reports indicate that the frequency of organ involvement can vary significantly according to region or race, even among patients with the same MSA.
The regional and/or racial differences observed in our study may be attributed to two primary factors: the prevalence of different anti-ARS antibodies (anti-Jo1, anti-PL-7, anti-PL-12, anti-EJ, anti-OJ, anti-KS, anti-Zo, and anti-Ha) and variations in HLA. It is well documented that clinical manifestations, course, and prognosis can differ depending on the type of anti-ARS antibody. For instance, myopathy is more frequent in patients positive for anti-Jo1 antibodies and less common in patients positive for non-Jo1 anti-ARS antibodies [22, 27]. Our analysis confirmed that the positivity rate for the anti-Jo1 antibody differed markedly among regions. Since the types and frequencies of other anti-ARS antibodies are also known to vary by population, these differing autoantibody profiles likely contribute to the observed variations in skin manifestations and prevalence of muscle weakness and ILD. Another potential contributor to regional variation is genetic predisposition, particularly involving HLA alleles, which are crucial for regulating immune responses and are implicated in various autoimmune diseases [28, 29]. A recent large immunogenetic analysis of 168 Caucasian patients with ASyS identified a statistically significant association between the HLA-DRB1*03:01 and HLA-B*08:01 alleles, while a decreased frequency of HLA-DRB1*07:01 was observed [30]. Interestingly, HLA-DRB1*03:01 allele was significantly more common in the anti-Jo1 positive group than in the anti-Jo1 negative group. Unfortunately, no comparable HLA analysis of patients with ASyS has been reported in Asian cohorts, precluding a direct comparison. However, it is plausible that underlying differences in HLA allele distribution could influence not only the susceptibility to ASyS but also its clinical characteristics across different populations.
This study has several limitations. First, this was a single-center retrospective study with a small number of enrolled patients. Second, there is a potential for evaluation bias based on clinical specificity, as ASyS is diagnosed in various departments (e.g., rheumatology, pulmonology, and dermatology), which may affect the evaluation of clinical manifestations. Third, statistical comparisons were limited to variables common across the selected cohorts, indicating that not all clinical characteristics could be compared. Therefore, our analysis alone cannot conclude that regional differences exist in the manifestation of ASyS. Fourth, no anti-ARS antibodies other than anti-Jo1 antibody were identified in our cohort, which prevented further analyses of anti-ARS antibody subtype-specific differences. Finally, the methods used for antibody detection (enzyme-linked immunosorbent assay, RNA immunoprecipitation, and line blot assays) varied between studies. These methodological differences may have affected the accuracy of the antibody positivity. Furthermore, our study did not include a detailed analysis of specific anti-ARS antibodies.
Conclusions
In conclusion, our findings suggest that regional differences may exist in the clinical features of ASyS, particularly in ILD prevalence, which may be linked to the underlying distribution of anti-ARS antibody subtypes. A more detailed profile analysis of each anti-ARS antibody using a standardized detection method in a larger population is warranted to further clarify these findings.
Acknowledgements
We would like to thank Editage (www.editage.com) for the English language editing.
Abbreviations
- ASyS
Antisynthetase syndrome
- IIMs
Idiopathic inflammatory myopathies
- ILD
Interstitial lung disease
- PM
Polymyositis
- DM
Dermatomyositis
- ARS
Aminoacyl transfer RNA synthetase
- CLASS
Classification Criteria for Antisynthetase Syndrome
- MSAs
Myositis-specific autoantibodies
- EULAR
European League Against Rheumatism
- ACR
American College of Rheumatology
- CADM
Clinically amyopathic dermatomyositis
- HLA
Human leukocyte antigen
Authors’ contributions
TW and YY conceived and designed the study. YO, MT, HK, IM, and MK collected data. TW and YY prepared the manuscript. All the authors read and approved the final manuscript.
Funding
No specific funding was received from any bodies in the public, commercial, or not-for-profit sectors for the work described in this article.
Data availability
All data generated or analyzed in this study are included in this published article and are available from the corresponding author on reasonable request.
Declarations
Ethics approval and consent to participate
This study was approved by the Institutional Review Board of Yokohama City University (approval no. B190800045). Consent to participate was not applicable.
Consent for publication
Not applicable.
Competing interests
The authors declare no competing interests.
Footnotes
Publisher’s note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Contributor Information
Tomoya Watanabe, Email: nabetomo@yokohama-cu.ac.jp.
Yukie Yamaguchi, Email: yui1783@yokohama-cu.ac.jp.
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Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.
Data Availability Statement
All data generated or analyzed in this study are included in this published article and are available from the corresponding author on reasonable request.