Attenuation of C protein-induced myositis (CIM) in mast cell-deficient W/Wvmice. CIM was induced in mast cell-deficient W/Wv mice (n = 10) and control congenic wild-type (WT) mice (n = 10). Twenty-one days after the induction, specimens of muscle were stained with hematoxylin and eosin. Representative photomicrographs, histological scores of inflammatory mononuclear cell infiltration (left panel), and necrotic muscle area (right panel) are shown. Dots show histological score and necrotic muscle area of individual mouse, and horizontal bars show the mean. *P <0.01.