Expression of endothelial adhesion molecules in vivo. Increased endothelial ICAM-2 expression in lymphoid malignancies.

The authors have compared the reactivity of monoclonal antibodies (MAb) directed against endothelial adhesion molecules (ICAM-1, ICAM-2, VCAM-1, ELAM-1) in hyperplastic, nonmalignant, and malignant lymph nodes. The authors demonstrate that the reactivity with ICAM-1 MAb is stronger in the high endothelial venules (HEV) and other smaller vessels (SV) in lymphomas compared with hyperplastic lymph nodes. Similarly, the reactivity of an ICAM-2 MAb (6D5) was shown to be higher in malignant lymph nodes compared with nonmalignant ones. ICAM-2 MAb stained both the HEV and SV. VCAM-1 MAb reacted strongly with germinal centers and its endothelial reactivity was higher in the lymphoma nodes. ELAM-1 MAb stained only faintly some endothelial cells in malignant tissue. These data suggest that besides the known regulatable endothelial adhesion molecules ICAM-1 and VCAM-1, the expression of ICAM-2 can be modified.