Immune-mediated necrotizing myopathy

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Immune-mediated necrotizing myopathy (IMNM) is a subgroup of the idiopathic inflammatory myopathies. There are three major subtypes based on autoantibodies, of which statin-associated autoimmune myopathy has been increasing in recent years. It is characterized by myopathological findings of multiple necrotic and regenerating fibers with little infiltration of inflammatory cells. [1] [2] [3]

Contents

Epidemiology

As many as 40% of patients previously diagnosed with polymyositis and 19% of "possible myositis" would be classified as IMNM, but with the increase in the use of statins in 2010s, the number of cases of immune-mediated necrotizing myopathy has also increased. It is considered that 20-40% of myositis cases are immune-mediated necrotizing myopathy. [1]

Classification

Depending on the autoantibody detected, it is classified into three major subtypes: anti-SRP antibody-positive immune-mediated necrotizing myopathy (30-40%), anti-HMGCR antibody-positive immune-mediated necrotizing myopathy (26-50%), and seronegative immune-mediated necrotizing myopathy (25-40%). [1]

References

  1. 1 2 3 Day, Jessica A.; Limaye, Vidya (2019). "Immune-mediated necrotising myopathy: A critical review of current concepts". Seminars in Arthritis and Rheumatism. 49 (3): 420–429. doi:10.1016/j.semarthrit.2019.04.002. ISSN   1532-866X. PMID   31109639.
  2. Milone, Margherita (2017). "Diagnosis and Management of Immune-Mediated Myopathies". Mayo Clinic Proceedings. 92 (5): 826–837. doi: 10.1016/j.mayocp.2016.12.025 . ISSN   1942-5546. PMID   28473041 . Retrieved 2025-04-11.
  3. Anquetil, Céline; Boyer, Olivier; Wesner, Nadège; Benveniste, Olivier; Allenbach, Yves (2019). "Myositis-specific autoantibodies, a cornerstone in immune-mediated necrotizing myopathy". Autoimmunity Reviews. 18 (3): 223–230. doi: 10.1016/j.autrev.2018.09.008 . ISSN   1873-0183. PMID   30639649.