Fig. 1

a Skeletal muscle with numerous scattered necrotic fibers (*) without signs of inflammation (hematoxylin and eosin, ×100). b Single skeletal muscle fiber in a state of myophagocytosis (hematoxylin and eosin, ×200); * marks another fresh single fiber necrosis. c Detection of membrane attack complex-positive immune complexes on small vessels (arrowheads), endomysial capillaries, sarcolemma, and cytoplasm in necrotic muscle fibers (*) (membrane attack complex, ×200). d Clear sarcolemmal and cytoplasmic upregulation of major histocompatibility complex class I (major histocompatibility complex-I, ×100)