Research progress of sporadic inclusion body myositis

Abstract

Sporadic inclusion body myositis (sIBM) belongs to the idiopathic inflammatory myopathy (IIM). sIBM often affect old male over 50 years of age with usually insidious onset, followed by a slowly progressive muscle weakness and atrophy. Laboratory examination shows the muscle enzyme level in patients is normal or mildly elevated.Muscle biopsy is characterized with endomysial inflammatory cell infiltration, rimmed vacuoles within muscle fibers, amyloid deposition and decreased muscle fibers.Under electron microscope, tubular filament inclusion is often observed.The new standard for the diagnosis of sIBM was established by the european neuromuscular center (ENMC) in 2011.In recent years, researchers have discovered a new autoantibody, the anti-cN1A (cytoplasmic 5'-nucleotidase 1A, cN1A) autoantibody, and confirmed its correlation with sIBM.Inclusion body myositis responds to immunotherapy poorly.The prognosis of the patients is related with patients' age, involvement of muscle fiber, and the combination of other diseases.It is important to discusses the epidemiology, etiology, pathogenesis, clinical manifestation, diagnosis and treatment of sIBM. Key words: Sporadic inclusion body myositis; Idiopathic inflammatory myopathy; Rimmed vacuoles; European Neuromuscular Center; Anti cN1A autoantibodies