Two cases with autoantibodies to small ubiquitin‐like modifier activating enzyme: A potential unique subset of dermatomyositis‐associated interstitial lung disease

The presence of anti‐aminoacyl tRNA synthetase (ARS) or anti‐melanoma differential‐associated gene 5 (MDA5) is strongly related to interstitial lung disease (ILD) in patients with dermatomyositis (DM). Several studies suggest a potential relationship between ILD and anti‐small ubiquitin‐like modifier activating enzyme (SAE) antibody in DM patients, but detailed clinical characteristics of anti‐SAE‐associated ILD still remain unknown. We have experienced 2 cases who were positive for anti‐SAE antibody, who presented with ILD in the context of clinically amyopathic DM. These 2 patients had the following common ILD characteristics: an insidious course with preserved pulmonary function; a limited extent of pulmonary lesions with subpleural peripheral‐dominant small ground glass opacity/consolidation on high‐resolution computed tomography; and a favorable treatment response. These findings suggest that anti‐SAE‐associated ILD is unique in terms of clinical and imaging features and differs from ILD associated with anti‐ARS or anti‐MDA5 antibody.