Regional differences in clinical manifestations of antisynthetase syndrome: a comparison between Asian and European cohorts.

backgroundAntisynthetase 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.

methodsWe 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.

resultsThe 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.

conclusionsThese 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.