Fig.3. Representative histological and immunohistochemical images for cells and kynurenine pathway enzymes in the early atherosclerotic lesion and atherosclerotic aneurysm.

B. HE staining and immunohistochemistry for smooth muscle cells (SMA), macrophages (CD68), kynureninase, KMO, B cells (CD20), plasma cells (CD138), T cells (CD3), and endothelial cells (CD31) in atherosclerotic aneurysm. Square in HE staining indicates an area of other high-magnification images. Advanced atherosclerotic change with medial degeneration and accumulation of lymphoid cells in adventitia. A peripheral nerve bundle expresses KMO (arrows) but not kynureninase and closely localizes with the lymphoid aggregate. Lymphoid aggregate comprises B cells, plasma cells, T cells, and macrophages with capillary vessels.