Inflammatory myopathies and systemic disorders: a review of immunopathogenetic mechanisms and clinical features.

The inflammatory myopathies are a heterogeneous group of muscle diseases characterized by muscle degeneration mediated by inflammatory processes. They may be idiopathic, as in polymyositis, dermatomyositis and inclusion body myositis, or associated with systemic disorders such as malignancies, overlap syndromes, and retroviral infection. The pathogenesis of each disease is discussed together with more recent molecular and cellular immunology findings. Salient diagnostic, clinical and pharmacological features are also reviewed.