[New insights in pathogenesis and therapy of sporadic inclusion body myositis (s-IBM)].

Sporadic inclusion body myositis (s-IBM) is a chronic progressive inflammatory myopathy which occurs preferentially in older patients. Histologic hallmarks are rimmed vacuoles and eosinophilic cytoplasmatic inclusions. The etiology is still unknown, but different pathogenetic mechanisms such as slow virus infection, autoimmunopathogenesis, myonuclear alterations, and mitochondrial defects have been implicated. A relation to neurodegenerative disorders and prion diseases has also been suggested. There is a poor response if any to immunosuppressive therapy. Stabilization of disease progression was shown only by intravenous immunoglobulin (IVIG) therapy. Future findings in the field of s-IBM pathogenesis may result in better therapeutic options.