Detection of enterovirus specific RNA sequences in muscle biopsy specimens from patients with adult onset myositis.

A subgenomic cDNA probe with broad specificity for a range of enteroviruses was used to test by an in situ hybridisation technique for the presence of enterovirus specific genomic sequences in muscle biopsy samples obtained from patients with chronic adult myositis. Virus specific RNA sequences were detected in 6/13 (46%) patients with idiopathic polymyositis or dermatomyositis. Control samples obtained from an equal number of patients suffering from other muscle disorders were negative. A monoclonal antibody specific for an enterovirus group was used to probe for viral antigens by indirect immunoperoxidase staining; all biopsy samples from test and control groups were negative.