<prompt> Diapedesis is -Immigration of leucocytes through the basement membraneImmigration of the leucocytes through the vessel wall to the site of inflammationAggregation of platelets at the site of bleedingAuto digestion of the cells.  <response>: Ans. is b i.e., Immigration of the leucocytes through the vessel wall to the site of inflammationo Diapedesis is the process of transmigration of leukocytes across the endothelium. The most impoant molecule responsible for diapedesis is called PECAM-1 Platelet endothelial cell adhesion molecule or CD-31. 