Migration of leukocytes across endothelial junctions: Some concepts and controversies

This article is not meant to be a comprehensive review of leukocyte migration or endothelial cell junctions. Rather, I have chosen some aspects of inflammation that might be of general interest to vascular biologists and have focused on the structural and molecular elements of the endothelial junction involved in these processes. These are all active (and some controversial) areas of investigation. I have tried to objectively present both sides of any controversies, while stating at the end the general consensus of the field.