genetic and environmental factors of atopy

Atopy is a common immune disorder characterized by raised IgE levels, which lead to clinical disorders (i.e. primarily bronchial asthma, atopic dermatitis and allergic rhinoconjuctivitis). Interleukin (IL)-4 and IL-13, derived from T-helper cell type 2 (Th2) subsets, are central in mediating IgE production and development of immediate hypersensitivity. Atopy is also characterized by Th1/Th2 skewing that derives from genetic and environmental factors. The prevalence of atopy has increased in recent decades, especially in developed countries among children and young adults. In the present review, we first discuss the relationship between the Th1/Th2 imbalance and the recent rise of allergy. Second, we present evidence that human genetic variation is also a key factor responsible for atopy.