Expression of PSGL-1 in human tissues. (A) Paraffin tonsil stained with KPL1. The vast majority of the lymphocytes in the T-cell zone (TZ) show dark staining, while the B-lymphocytes in the mantle (M) and germinal center (GC) do not stain. (B) A high magnification of paraffin embedded tonsil stained with KPL1. Plasma cells adjacent to the overlying epithelium show dark membrane staining. The mantle B lymphocytes in the right lower corner do not stain. (C) Plasma cells near vessels in skin stain well with KPL1. (D) Costaining of the cells in (C) with VS38 confirms their identification as plasma cells.

(E) Paraffin section of skin stained with KPL1. The Langerhans cells in epidermis and superficial dermis stain intensely in this example of Langerhans cell histiocytosis. The stained dendritic processes are apparent in the epidermis. (F) Langerhans cells in soft tissues also stain with KPL1. (G) Identification of Langerhans cells in (F) is confirmed by costaining with CD1a (immunoperoxidase with hematoxylin counterstain).