Expression of Fas antigen is not associated with apoptosis in human myopathies.

To determine whether the Fas-Fas-ligand mediated apoptosis occurs in the pathologic process of human muscle diseases, we examined the expression of Fas antigen, Fas-ligand messenger RNA, and chromosomal DNA fragmentation in the muscle cells of patients with a variety of human muscle disorders. The present study demonstrated that the Fas antigen of a whole molecule was expressed on the muscle fibers of patients with muscle wasting diseases. However, the apoptotic process did not occur in the muscle cells, and there was no evidence of Fas-ligand synthesis in the diseased muscle tissue. Our data suggest that the expression of Fas antigen on fibers in diseased muscle is related to unknown biological functions other than "apoptosis" in the process of muscle fiber injury.