Myositis-specific autoantibodies: an important tool to support diagnosis of myositis

The idiopathic inflammatory myopathies are characterised by muscle weakness, skin disease and internal organ involvement. Autoimmunity is known to have a role in myositis pathogenesis, and myositis specific autoantibodies, targeting important intracellular proteins, are regarded as key biomarkers aiding in the diagnosis of patients. In recent years a number of novel myositis autoantibodies including; anti-TIF1, anti-NXP2, anti-MDA5, anti-SAE, anti-HMGCR and anti-cN1A have been identified in both adult and juvenile patients. These autoantibodies correlate with distinct clinical manifestations, and importantly are found in the inclusion body, statin-induced, clinically amyopathic and juvenile groups of myositis patients that were previously believed to be mainly autoantibody negative.