Expression of E- and P-selectins by vascular endothelial cells in human tonsils.

Selectins play an important role in the adhesion between vascular endothelial cells and leukocytes in immuno-inflammatory events. We investigated the immunohistochemical localization of E- and P-selectins in the human palatine tonsils at light and electron microscopic levels. E-selectin was expressed by high endothelial venules (HEV) in a linear pattern in heavily inflamed tonsils with focal infection and extensive neutrophilic infiltration, and much less in hypertrophic tonsils without focal infection. P-selectin expression was found on HEV to the same extent in both disease states in a dot pattern in the cytoplasm. Immunoelectron microscopically, E- and P-selectins were localized along the luminal plasma membrane and in the perinuclear space in HEV endothelial cells. The present study suggests that increased expression of E- and P-selectin in vascular endothelial cells is a significant feature of inflamed tonsils induced by focal infection. E- and P-selectins may participate in different roles in the inflammatory process of the tonsils.