Inflammatory bowel diseases share common pathogenetic mechanisms that are not 
yet completely understood. It is clear, however, that the expression and 
production of cytokines in response to inflammation plays a key role in 
mediating the migration of activated leukocytes. The process of angiogenesis and 
the expression of adhesion molecules on the intestinal microvasculature act as 
gateways, facilitating the recruitment of leukocytes into the gut mucosa. New 
agents specifically blocking adhesion molecules, in particular integrins, have 
been developed in order to limit the passage of activated leukocytes into the 
mucosa. Non-gut-specific anti-integrin agents, such as natalizumab, have been 
shown to be effective in the treatment of IBD, but the risk of serious adverse 
events has limited their further development. The development of a new specific 
molecule, vedolizumab, is currently under investigation in a large clinical 
trial. This novel specific anti-integrin drug seems to hold promise in the 
treatment of gut inflammation.