Reactivity of the Endothelial Cell Marker EN4 With Malignant B-Cells in Low-Grade Malignant Lymphomas and with Subpopulations of B- and T-Cells in Blood and Reactive Lymphoid Tissue

Expression of the endothelial cell marker EN4 was studied by immunohistochemical staining in 56 biopsies of malignant Non-Hodgkin lymphomas (NHL), Hodgkin's disease, reactive lymphatic tissue and in non-lymphatic organs and by flow-cytofluorometry in blood and tonsil cell suspensions.In addition to positivity in endothelial cells, MAb EN4 reacted with numerous leukocytes localized in perivascular zones, mostly T lymphocytes and monocytes/macrophages. Neoplastic B cells of low-grade lymphocytic and centrocytic NHL, immunocytomas and neoplastic T (CD3+/CD4+) cells from one lymphoblastic lymphoma were also positive. In contrast, however, centroblastic/centrocytic NHL, high grade malignant B-cell lymphomas and Reed-Sternberg cells in Hodgkin's disease were negative.The majority of B-cells and CD8 positive T-cells both in blood and tonsil cell suspensions were EN4 positive. CD4+ cells were EN4 positive but to a lesser extent. All CD14 positive monocytes, all granulocytes and the majority of CD56 positive cells...