EXPRESSION OF INDUCIBLE CELL-ADHESION MOLECULES IN THE NORMAL HUMAN LUNG - IMMUNOHISTOCHEMICAL STUDY OF THEIR DISTRIBUTION IN PULMONARY BLOOD-VESSELS

The distribution of cell adhesion molecules in the normal human lung w as investigated using antibodies to E-selectin, P-selectin, intercellu lar adhesion molecule 1 (ICAM-1), and vascular cell adhesion molecule 1 (VCAM-1). Lectin staining by Ulex europaeus type I agglutinin (UEA I ) and immunohistochemistry for von Willebrand factor (vWF) was used to visualize a maximum of blood vessels per section. In the bronchial mu cosa, staining for P-selectin was positive in ca 90%, and staining for E-selectin, VCAM-1, and ICAM-1 was positive in 40-70% of the vessels stained with UEA I. In the pulmonary circulation (vasa publica) ca 90% of non-capillary vessels stained by anti-vWF expressed P-selectin, 54 % VCAM-1, 41% E-selectin, and only ca 20% ICAM 1. The alveolar capilla ries were stained consistently by UEA I, but not by the panel of antib odies tested. The alveolar epithelium and, inconstantly, basal cells o f the bronchial epithelium were positive for ICAM-1. The distribution pattern of inducible adhesion molecules in normal human lung tissue su ggests that a permanent low-grade endothelial activation may exist in particular in the mucosa of the airways, which could be due to the nor mal antigen exposure via inhaled air.