Abstract
Immunohistochemical examinations using monoclonal antibody against subunit IV of cytochrome c oxidase were carried out in the muscle of patients with various mitochondrial myopathies having histochemical partial deficiency of cytochrome c oxidase activity. The ragged red fibers showed positive reaction for the monoclonal antibody even in the histochemical cytochrome c oxidase deficient fibers. However, in the histochemical cytochrome c oxidase deficient fibers with normal histological appearance, the immunohistochemical reaction varied. While all fibers with immunohistochemical deficient reactivity for subunit IV of cytochrome c oxidase had no detectable histochemical cytochrome c oxidase activity, subunit IV protein deficiency was not the cause of all the histochemical cytochrome c oxidase deficient fibers.
