Immune-mediated necrotizing myopathy

Immune-mediated necrotizing myopathy (IMNM) is a newly identified subgroup of idiopathic inflammatory myopathies. It is defined as a rare and severe disease, with symmetrical and proximal muscle weakness and a characteristic histology. An autoimmune aspect of IMNM is suggested by its association with autoantibodies directed against signal recognition particle (SRP) and 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCR) in the majority of patients. Statin use is strongly associated with anti-HMGCR-positive IMNM. The pathophysiological mechanisms of this disease are still poorly understood, and as a result, no therapeutic strategy has been validated to date. The aim of this article is to provide an overview of the current knowledge about epidemiology, clinical features, and pathophysiology of IMNM, as well as treatment strategies. IMNM is a subject of widespread interest, with quick and meaningful advances being made. In recent years, huge progress has been made in terms of diagnosis and patient management. However, the understanding of pathophysiological mechanisms and treatment strategies still requires further investigation.