J Rheumatol
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The detection and characterization of a large array of autoantibodies, including at least 8 different antisynthetase, anti-SRP, -200/100 (HMGCR), -Mi-2, -CADM-140 (MDA5), -SAE, -p155, -MJ (NXP-2), and -PMS1, frequently associated with distinct and well-defined clinicopathological features, allowed for significant improvement in the definition and diagnosis of idiopathic inflammatory myopathies (IIM). Classification remains difficult, with lingering divergence between the different specialties involved in IIM care, but several categories clearly stand out, including dermatomyositis (DM), overlap myositis (OM), polymyositis, necrotizing myositis, and sporadic inclusion body myositis (s-IBM). Biopsy and histological analysis remain crucial, particularly in the absence of autoantibodies, to accurately specify the diagnosis and rule out mimics such as muscular dystrophies and metabolic myopathies. ⋯ Exercise, initially seen as potentially deleterious, recently was shown to be efficacious and safe. IIM can thus be reasonably well controlled in most cases, although aggressive disease remains refractory to treatment, including some cases of necrotizing myopathy. Sporadic IBM still seems resistant to all medications tested to date.