Focus on Myositis

Multiple genetic and environmental factors contribute to the risk of developing idiopathic inflammatory myopathies; both immune and non-immune related mechanisms are involved in the pathogenesis of these disorders, the understanding of which might lead to novel treatment approaches.

The idiopathic inflammatory myopathies are a group of disorders that involve inflammation of skeletal muscles and extramuscular manifestations. New classification criteria capture a broad range of these disorders but should be further defined in the future to incorporate new data.

Myositis-specific or myositis-associated antibodies can be found in most patients with myositis and are associated with distinct disease phenotypes. These antibodies also provide valuable insights into the pathogenesis of myositis and can help guide treatment.

Many immunosuppressive and immunomodulatory therapies are available to clinicians for managing myositis, and numerous biologic and small-molecule therapies are emerging that target implicated pathogenic targets. However, care must be taken when considering the numerous extramuscular complications of this disease.

The idiopathic inflammatory myopathies are characterized by muscle weakness and inflammation. A range of tools are available to evaluate outcomes in the treatment of myositis, including, among others, core set measures that were developed by international networks of myositis researchers.

Interstitial lung disease (ILD) is a major cause of death and disability in patients with polymyositis or dermatomyositis. To begin to improve patient outcomes, the clinical, demographic and therapeutic factors associated with poor prognosis for patients with ILD associated with polymyositis or dermatomyositis need to be identified.

What causes muscle fibre necrosis in necrotizing myopathy? The authors of a new study propose that specific autoantibodies contribute to disease via immune-mediated processes; but given that these processes also occur in muscular dystrophies, how likely is that these antibodies trigger muscle fibre necrosis?