Epigenetics of allergy.

Epigenetics has recently been considered as a potential mechanism involved in the development of many disorders, including allergic diseases. Animal models have shown that environmental factors such as maternal tobacco smoke or mechanical ventilation can alter gene transcription and consequently the structure and function of lungs. Moreover, asthma and other allergic diseases (atopic dermatitis and food allergy) are influenced by epigenetics. In fact, the exposure to environmental factors during early childhood may induce a long-lasting altered genetic state adapting to a persistent "Th2 state" thus influencing the development of asthma or atopic dermatitis and food allergy if alterations involve the filaggrin gene. In conclusion, progresses have been made linking environmental pollution, environmental tobacco smoke (ETS) and diet exposure with atopy through epigenetic mechanisms. Furthermore, considerable advances have been made implicating epigenetic mechanisms in T cell differentiation. However, much more research is still needed, in particular to define the clinical consequences of such epigenetic alterations.