Dermatomyositis, polymyositis, and Coxsackie-B-virus infection.

Coxsackie-B-virus-specific probes prepared by reverse transcription of purified virus genomic RNA and molecular cloning techniques were used in quantitative slot-blot hybridisations to test for the presence of virus RNA in skeletal muscle biopsy samples. The samples tested were from two patients with adult polymyositis, seven with juvenile dermatomyositis, four with Duchenne muscular dystrophy, and six normal controls. Of the nine patients with inflammatory muscle disease, five were positive for Coxsackie-B-virus RNA; no viral sequences were found in the ten Duchenne muscular dystrophy and control biopsy samples.