X-LINKED VACUOLATED MYOPATHY - MEMBRANE ATTACK COMPLEX DEPOSITION ON THE SURFACE-MEMBRANE OF INJURED MUSCLE-FIBERS IS NOT ACCOMPANIED BY S-PROTEIN

We have studied the expression of S-protein on the muscle from patient s with X-linked vacuolated myopathy [characterized by the deposition o f the complement C5b-9 membrane attack complex (MAC) over abnormal mus cle fibers] and controls by immunocytochemistry and immunoblotting, No expression was detected on muscle from controls and patients with X-l inked vacuolated myopathy. These findings suggest that S-protein does not render the MAC inactive in X-linked vacuolated myopathy. This situ ation may be due to the fact that the pathways of MAC activation and t he expression of S-protein in X-linked vacuolated myopathy are differe nt from the ones observed in ischemic and/or necrotic, or immune disea ses. These results emphasize the role of the membrane complement regul atory proteins (i.e., CD59) in X-linked vacuolated myopathy. (C) 1998 John Wiley & Sons, Inc.