Dermatomyositis Clinical and Pathological Phenotypes Associated with Myositis-Specific Autoantibodies

Dermatomyositis is an idiopathic inflammatory myopathy with a variety of systemic and cutaneous manifestations. The myositis-specific autoantibodies (MSAs) are associated with phenotypic features and provide a tool for sub-classification of dermatomyositis patients. This review focuses on recent work characterizing the clinical features that accompany the MSAs in dermatomyositis. There is increasing recognition of the distinct clinical and pathological phenotypes associated with each MSA. Most of these features display considerable overlap between MSA groups. Despite this, there are notable differences between the typical combinations of cutaneous and systemic manifestations, response to therapy, prognosis, and disease sequelae that define each dermatomyositis MSA group. The MSAs may ultimately improve diagnosis and sub-classification of dermatomyositis patients. However, more work is needed to understand the pathologic basis for much of the heterogeneity found within these subgroups.