Potential therapeutic targets for idiopathic inflammatory myopathies.

The inflammatory myopathies essentially comprise three diseases with different immunopathologic features. Dermatomyositis (DM) is a complement-mediated microangiopathy. The immune response in polymyositis (PM) and sporadic inclusion body myositis (IBM) is a CD8+ T-cell-mediated cellular reaction against an unknown muscle fiber antigen. The multiple immune factors that guide inflammatory cell diapedesis and trafficking have been elucidated over the past two decades. Many of these molecules can now be targeted by monoclonal antibodies and other pharmacologic approaches. Randomized controlled trials are being started on a number of new agents to find out whether more specific immune interventions than the currently used glucocorticosteroids can treat DM and PM patients with fewer side effects, and may represent a first treatment modality for IBM, an entity unresponsive to all currently available pharmacological treatments.