Recently, a number of myositis-specific and -associated autoantibodies (MSAs/MAAs) have been identified and well characterized, and commercial assays for their detection have become available.<b>Areas covered</b>: There is accumulating evidence showing the utility of MSAs/MAAs in diagnosis of DM and in predicting clinical courses and outcomes in patients with DM as convenient biomarkers, i.e. an association of ILD with anti-ARS, anti-MDA5 and anti-SAE; and malignancy with anti-TIF1-γ, anti-NXP2, and anti-SAE in adults.
Moreover, anti-MDA-5 is associated with amyopathic myositis and interstitial lung disease and anti-TIF-1γ and anti-NXP-2 with juvenile DM as well as malignancy in patients >40 years.
Autoimmunity tests showed positivity for antinuclear antibodies and anti-NXP2, a recently described antibody associated with juvenile DM and, more rarely, with paraneoplastic DM.