Anti-vimentin staining in muscle pathology.

The intermediate filaments of immature muscle fibres contain desmin and vimentin; vimentin is lacking in mature fibres. Regenerating fibres react with anti-vimentin antibodies and more intensely for desmin than mature fibres. The aim of the present study was to evaluate anti-vimentin staining for muscle pathology. Anti-vimentin-reactive fibres were found in 40 of 89 biopsies assessed. Fifteen patients with progressive destructive myopathy, infantile spinal muscular atrophy, clinically suspected Leigh's disease or unclassifiable congenital myopathy had between 1% and 95% vimentin-positive fibres. Less than 1% positive fibres were found in 25 patients with neuropathy with secondary myopathy or chronic myopathic conditions. Vimentin-positive fibres were lacking in 20 normal biopsies, in eight biopsies with neuropathic and in 21 biopsies with mild or non-destructive myopathic changes. We conclude that staining with anti-vimentin antibodies is a useful indicator for muscle fibre regeneration; it may help establish the diagnosis in infantile spinal muscular atrophy when the histopathology is non-characteristic. The high incidence of reactive fibres in some congenital or early-onset disorders may indicate developmental arrest.