Siglec-8 and Siglec-F, the new therapeutic targets in asthma.

The recruitment of eosinophils from the circulation into the airway is a prominent feature of allergic asthma. Persistent inflammatory responses may arise from inefficient mechanisms for resolution of inflammation, including delayed apoptosis. Several studies suggest that eosinophil apoptosis is delayed in asthma. Sialic acid-binding immunoglobulin-like lectins are characterized by their sequence similarities and abilities to bind sialic acids in glycoproteins and glycolipids. Siglec-8 is uniquely expressed on eosinophils, mast cells, and basophils. Engagement of Siglec-8 on blood eosinophils results in caspase- and mitochondria-dependent apoptosis. Eosinophil apoptosis is an important therapeutic target for the development of novel anti-asthma treatments that specifically target the eosinophil.