Interferons as components of the complex web of reactions sustaining inflammation in idiopathic inflammatory myopathies

•IFN expression is associated with IM muscle pathology.•The IFN type 1 signature of DM is associated with perifascicular muscle fibre atrophy and disease activity.•IFN type 1 is an amenable therapeutic target currently under investigation for DM.

Evidence accumulates implicating interferons (IFNs) in the chronic inflammation associated with the idiopathic inflammatory mypathies (IM). Dermatomyositis in particular appears to display a strong IFN type 1 signature. Proposed pathogenic actions of IFNs include the upregulation of major histocompatibility complex class I on muscle fibres, and the induction of a plethora of pro-inflammatory factors, including cytokines and chemokines. This review brings together findings on IFNs and IFN-induced factors, sketching their roles in IM immunopathogenesis in general and dermatomyositis in particular, and offering a basis for exploring their potential therapeutic relevance.