The Epigenetics of Food Allergy

Abstract

Food allergy is a global health problem, particularly in developed countries. It is mainly mediated by Th2 cell and IgE produced by B cells. While the pathogenesis of IgE-mediated food allergy is quite straightforward, the factors that lead to the development of food allergies at any age in children and adults are unclear. Recent studies have revealed that genetics, epigenetics, and environmental exposures contribute to the development of atopy. In this chapter, we discuss the interplay between these three key elements, reveal how epigenetic modifications may mediate genetic susceptibility of food allergies, and explain why epigenetic modifications may be the key in environmental factors mediated-gene expression, leading to the loss of immune tolerance and eventually, the initiation of food allergies. It should be noted that the study of the role of epigenetics in food allergy is still in its infancy, and lags behind research on epigenetics in other fields such as cancer and autoimmune diseases. One of the reasons for this may be the extreme complexity and variability of clinical presentation of food allergy, ranging from less severe forms such as oral allergy syndrome to full-blown anaphylaxis. Research on early exposure has disrupted the previous thinking of avoidance of food allergies to prevent sensitization in children, instead leading to recommendations that early introduction to foods may, in fact, induce tolerance. However, clear and unequivocal guidelines on how to approach this in the clinical setting have not been developed. The coming of the epigenetic era in food allergies is to provide better understanding of pathogenesis of food allergy, as well as providing therapeutic and preventive strategies for this very common condition.