Role of dendritic cells in dermatomyositis

Abstract

Background Dermatomyositis (DM) is a rare idiopathic inflammatory myopathy characterized by the combination of progressive muscle weakness and distinct cutaneous manifestations. It affects both adults and children and may involve multiple organ systems beyond skin and skeletal muscle, most notably the lungs. Clinically, DM typically presents with symmetric proximal muscle weakness leading to functional impairment, while distal muscle strength is usually preserved. Pathognomonic skin findings such as Gottron papules, Gottron’s sign, and heliotrope rash are key diagnostic features. Pulmonary involvement, particularly interstitial lung disease, represents a major prognostic determinant. Methods This thesis provides a narrative review of the current literature on DM, focusing on clinical presentation, diagnostic approaches, and underlying immunopathogenic mechanisms. Diagnostic strategies including clinical assessment, laboratory testing, imaging modalities, electrophysiological studies, and histopathological evaluation are discussed. Special emphasis is placed on recent advances in immunology, particularly the role of dendritic cells and type I interferon–mediated pathways. Results The diagnosis of dermatomyositis relies on a combination of characteristic clinical features and supportive laboratory, imaging, and histopathological findings. Elevated muscle enzymes and the presence of myositis-specific autoantibodies contribute to disease classification and prognostic stratification. Magnetic resonance imaging and electromyography provide non-invasive evidence of muscle inflammation, while muscle biopsy remains the diagnostic gold standard, demonstrating perifascicular atrophy, inflammatory infiltrates, and complement-mediated microangiopathy. Recent evidence highlights the central role of plasmacytoid and myeloid dendritic cells in driving chronic inflammation through excessive type I interferon production. This interferon signature is closely associated with systemic manifestations, including interstitial lung disease. Conclusion Dermatomyositis is a complex multisystem autoimmune disease with heterogeneous clinical manifestations and outcomes. Immunopathogenic mechanisms involving dendritic cells and type I interferon signaling play a pivotal role in disease development and progression. A comprehensive diagnostic approach integrating clinical, serological, imaging, and histopathological findings is essential for accurate classification and prognostic assessment. Improved understanding of these immune-mediated processes may facilitate earlier diagnosis and support the development of targeted therapeutic strategies, particularly for patients with severe extramuscular involvement.

Datum der Bewilligung	2026
Originalsprache	Englisch
Gradverleihende Hochschule	Medizinische Universität Graz
Betreuer/-in	Helmut Popper (Betreuer*in) & Monica Dorazio (Mitbetreuer*in)