Neutrophil-endothelial cell interactions in the lung.

The large marginated pool of neutrophils normally present in the pulmonary circulation provides a unique opportunity to study the relationship between neutrophils and endothelial cells in situ. Unlike other organs in which neutrophil density in the vascular space is low, adequate numbers of cells are readily available in the lung to assess such important characteristics as distribution, density, size, volume, and immunocytochemical and cytochemical characteristics. To take advantage of such a large marginated pool, morphologic techniques should be more universally applied in studies of neutrophil-mediated tissue injury. From the data presented, it seems clear that factors governing neutrophil-endothelial cell interactions may differ in the lung compared to systemic vascular beds. We have suggested that this difference may be related to the unique characteristics of the lung with regard to anatomy and blood flow rather than site-specific differences in endothelial cells. With the discovery of specialized proteins involved in cell adhesion and the increasing availability of appropriate antibodies to adhesion proteins, unprecedented opportunities exist to address these questions. It is an exciting time to study neutrophil-endothelial cell interactions in the lung.