Mechanisms regulating eosinophil extravasation in asthma

Infiltration of eosinophils into tissue allergic inflammation is mediated by a combination of processes. Eosinophil L-selectin and very late activation antigen (VLA-4) can selectively regulate eosinophil adhesion to the endothelium. Activating cytokines, such as interleukin (IL)-5, regulated upon activation in normal T-cells (RANTES) and monocyte chemotactic peptide (MCP)-3 specifically act on eosinophils. Moreover, eosinophils from allergic individuals can be primed for increased adhesion and movement by chemokines released at sites of allergic inflammation. Together, these processes induce a specific infiltration of eosinophils.