Endothelial activation antigens in pulmonary leukostasis in leukemia

Adhesion between leukemic cells and the vascular endothelium has been suggested to play a role in the development of leukostasis in myelocytic leukemia. To define the role of adhesion molecules on the surface of endothelial cells in leukostasis, we used immunohistochemistry to study the expression of endothelial leukocyte adhesion molecule-1 (ELAM-1), vascular cell adhesion molecule-1 (VCAM-1), and intercellular adhesion molecule-1 (ICAM-1) in lung tissue of 4 patients with pulmonary leukostasis. Lung tissue of 2 patients with myelocytic leukemia without leukostasis and 4 patients with irrelevant nonpulmonary disease was used as a negative control. Positive control tissues included a lymph node with angioimmunoblastic lymphadenopathy and a hyperplastic tonsil. Weak positive staining for ELAM-1 was found in 1 patient in vessels, both with and without leukostasis. Expression of VCAM-1 and ICAM-1 in all patients tested was similar to that in the negative controls. The results of this study suggest that activation of endothelium, with increased expression of the endothelial adhesion molecules under study, is not a prerequisite for the development of pulmonary leukostasis in leukemia.