Large, irregular-shaped positive cells predominantly in follicles appear to be macrophages. Arrowhead indicates small, intensely positive cells, within high endothelial venules.
Should have diluted further as positivity is far too intense and cytoplasm of viable COR1 cells is moderately positive.
There is nuclear positivity: additionally there is Golgi positivity.
Comments are welcome.
From top to bottom: Abcam ab79351, ab97959, Santa Cruz sc-17320