Selectins play an important role in the adhesion between vascular endo
thelial cells and leukocytes in immuno-inflammatory events. We investi
gated the immunohistochemical localization of E- and P-selectins in th
e human palatine tonsils at light and electron microscopic levels. E-s
electin was expressed by high endothelial venules (HEV) in a linear pa
ttern in heavily inflamed tonsils with focal infection and extensive n
eutrophilic infiltration, and much less in hypertrophic tonsils withou
t focal infection. P-selectin expression was found on HEV to the same
extent in both disease states in a dot pattern in the cytoplasm. Immun
oelectron microscopically, E- and P-selectins were localized along the
luminal plasma membrane and in the perinuclear space in HEV endotheli
al cells. The present study suggests that increased expression of E- a
nd P-selectin in vascular endothelial cells is a significant feature o
f inflamed tonsils induced by focal infection. E- and P-selectins may
participate in different roles in the inflammatory process of the tons
ils.