Idiopathic Inflammatory Myopathies: Myositis-Specific Antibodies, Disease Subsets, and Emerging Therapies

This chapter reviews the rapidly evolving nosology of idiopathic inflammatory myopathies, with emphasis on the clinical and prognostic significance of myositis-specific and myositis-associated autoantibodies in delineating disease subtypes including dermatomyositis, anti-synthetase syndrome, immune-mediated necrotizing myopathy, and overlap myositis. The chapter also evaluates current immunosuppressive regimens and investigational biological therapies targeting type I interferon and JAK–STAT pathways.