Why vessels do not leak when leukocytes migrate out

Local inflammation is characterized by leukocytes that migrate out of the circulation by penetrating the vascular endothelial lining. It is remarkable that during this event, there is hardly any leakage. How does the endothelium manage to maintain its integrity while numerous leukocytes penetrate? That is one of the key questions in the field of inflammation, and in this issue of Blood, Braun and colleagues may have provided the answer.(1)