Immunohistochemistry of normal and atherosclerotic tissue. Immunohistochemistry for each of the 3 proteins was performed on sections of arterial tissue from 5 patients with atherosclerosis. The results from one representative patient are shown. Low-power hematoxylin and eosin staining of normal (A) and atherosclerotic plaque (H). Platelet incorporation into the plaques was demonstrated by staining for the platelet-specific proteins PF4 (J) and CD41 (I). Secretogranin III (L) and calumenin (M) were widely expressed in the plaque, whereas vascular smooth muscle cells in the lesion, identified by smooth muscle actin staining (G,N), stained for cyclophilin A (K). No staining for secretogranin III, calumenin, or cyclophilin A was observed in sections of normal artery (B-F). Original magnification × 2.5 (A, H); × 63 (B-G, I-N).