COEXPRESSION OF ENDOTHELIAL-CELL AND MACROPHAGE ANTIGENS IN KAPOSIS-SARCOMA CELLS

The histopathogenesis of Kaposi's sarcoma (KS) was investigated using immunocytochemistry in 12 skin biopsies obtained from two AIDS patients, nine patients with the classic form, and one organ-transplant patient. KS cells revealed a peculiar antigenic profile, being characterized by co-expression of endothelial and macrophage markers. KS cells were stained for von Willebrand factor (VWF); for vascular endothelial (VE) cadherin, an endothelial specific adhesion molecule; and for PECAM/CD31. In addition, they expressed the macrophage antigens PAM-1, CD68, and CD14, and were positive for vitronectin receptor and alpha-1,5,6/beta-1 integrins. KS cells were weakly stained for ICAM-1 in 6 of 12 cases and were negative for VCAM-1 and E-selectin.