Immunocytochemical studies on desmin and vimentin in neuromuscular disorders

Desmin and vimentin are two intermediate filaments, abundant in fetal skeletal muscle, almost undetectable in mature skeletal muscle which increase in regenerating and partially damaged skeletal muscle fibers. To determine their content in neuromuscular disorders immunohistochemical studies of desmin and vimentin were performed on 53 human muscle specimens. The labelled streptavidin biotin technique (DAKO, LSAB Kit, alkaline phosphatase) was used. Strong staining intensity was seen in regenerating and partially damaged fibers of inflammatory myopathies and muscular dystrophy. Necrotic fibers lost their reactivity for both filaments. Type II glycogenosis showed an increased reactivity for desmin and vimentin. A mild increase in desmin and vimentin staining intensity was observed in the atrophic cells of spinal muscular atrophy, but not in the atrophic fibers from other disease entities. Weaker reactivity for desmin was noted in atrophic cells of myotonic dystrophy. The immunohistochemical study of desmin and vimentin in neuromuscular disorders is helpful in detecting degeneration, or regeneration changes, of muscle fibers and may provide clues to the pathogenesis of various muscular disorders.