ABSTRACT
As outlined in previous chapters, the development of allergic asthma is causally related to the activation of allergen-speci¢c type 2 T-helper lymphocytes (Th2 cells). Here we review the recent progress in our understanding of the mechanisms that underlie the development of the various phenotypes of Th cells.We will also discuss some of the concepts explaining the predominant occurrence of allergen-speci¢cTh2 cells in allergy.
