Several myositis-specific antibodies are detected in the serum of patients with IIM, the most frequent being antisynthetase antibodies, found in more than 20% of cases. Anti-Jo-1 is the most common, followed by anti-PL-12 and anti-PL-7. Patients with antisynthetase antibodies show a specific phenotype, known as antisynthetase syndrome (ASS), which includes myositis, ILD, arthritis, fever, Raynaud phenomenon, and skin thickening on the sides of the fingers, referred to as mechanic’s hands (Fig 2). Lung involvement is more common in patients with ASS than in antibody-negative cases, with a reported prevalence of ILD of 80% to 100%. Moreover, ILD can occur without muscle inflammation (amyopathic or hypomyopathic DM). Therefore, antisynthetase antibodies should always be tested, not only in patients with DM, but also in patients with ILD of unknown origin, because they seem to determine the frequency, course, and severity of lung disease, although there are no prospective studies to clarify this issue conclusively.