New observations in reducing body myopathy.

Numerous autofluorescent reducing bodies were found in deltoid and biceps muscle biopsies of a 7-year-old girl with progressive, asymmetric muscle weakness. The structures were composed of tubular filaments as seen by electronmicroscopy. They seemed to have formed around nuclei. An excess of two unidentified proteins was found in muscle homogenates. This patient, like one previously reported, had high serum titers of antibodies to coxsackievirus, but her serum, when tested by indirect immunocytochemistry, did not react with the reducing bodies.