[Immunostaining of anti-Fas IgG1 antibody in diseased human muscle].

Immunostaining of the Fas antigen using the anti-Fas IgG1 antibody was performed on biopsied human diseased muscles. The immunostaining showed negative results in the control muscles. In dystrophinopathy [DMD and BMD], positivity was seen mainly in type 2 fibers with no correlation to the opaque fibers and histochemical Ca2+ loading fibers in DMD. In DMD carriers, a relative correlation was seen between dystrophin-negative and Fas-positive fibers. In distal myopathy with rimmed vacuoles, fibers with positive staining in the vacuoles but negative in their membranes were seen at high frequency. In FSH, a very low frequency of positivity was seen. And in myotonic dystrophy, positivity was seen in the type 2 fibers containing the internal nuclei. In inflammatory myopathies, strong positivity was seen in the medium size fibers, and mild to moderate positivity in the fibers facing the perimysium. In neurogenic muscular disorders, fibers with concave borders or highly atrophic fibers showed Fas-positivity. In conclusion, there was no disease-specific Fas reaction in the human pathologic muscle samples, but the high positivity was apparent in some myopathies. This fact of Fas antigen would reflect a pathologic state in the skeletal muscle.