The muscle tissue transcriptome of idiopathic inflammatory myopathy reflects the muscle damage process by monocytes and presence of skin lesions.

Our study highlights a significant involvement of monocytes in muscle damage and delineates pathological differences among IIM subtypes. DM was characterized by complement, interferon-α and -γ signaling, whilst ARS-DM was associated with OXPHOS. Distinctive gene expression variations in muscle specimens suggest that different pathologic mechanisms underlie muscle damage in each IIM phenotype.