This study on primary human cells demonstrates that basophils and eosinophils are the only direct target leukocytes for IL-33, suggesting that IL-33 promotes allergic inflammation and Th2 polarization mainly by the selective activation of these specialized cells of the innate immune system.
IL-33 and its receptor, ST2, may play important roles in eosinophil-mediated inflammation; they may provide new therapeutic targets for controlling mucosal eosinophilic inflammation.
Taken together, these results suggest that IL-33 may play an important role in mast cell-mediated inflammation and further emphasize the role of innate immunity in allergic diseases.