IMMUNOTHERAPY FOR FOOD HYPERSENSITIVITY

Abstract

Foods are an important cause of severe acute hypersensitivity reactions including fatal anaphylaxis. Food allergy has been estimated to be the most frequent cause of anaphylaxis treated in emergency rooms. 69 Severe reactions to foods can occur at all ages, from infants receiving cow's milk or casein or whey hydrolysate formulas 21 , 57 to children, adolescents, and adults. 56 , 70 Although some reactions caused by formula proteins in infants may decrease in intensity with age, 7 the risk for severe reactions to other foods persists for long periods of time, even in absence of exposure. 8 The current management of patients with severe acute food reactions is based on avoidance of specific foods and on the availability of emergency medications to immediately treat an acute reaction. These severe reactions have been associated with fish, shellfish, nuts and seeds, legumes, celery, and to a lesser extent with grains, milk, and eggs. 7 , 8 , 70 It is clear from looking at this list that even the most careful patients may not be safe from an accidental or inadvertent exposure. In most instances, individuals experiencing a food-induced anaphylactic reaction have inadvertently ingested the food that caused the allergic reaction. 56 The unpredictability of accidental exposures and the long periods of time during which patients at risk may not come in contact with the offending foods makes it difficult to have acute treatment medications available at all times, which is necessary for the prevention of fatal food reactions. 56 , 70 The vast majority of the acute, severe reactions to food appear to be IgE-mediated, although non–IgE-mediated reactions can also account for some severe food reactions. 28 The presence of IgE antibodies as the likely cause for severe acute food reactions suggests the possibility of changing this allergic reactivity to a less noxious or even protective form of immune response through immunotherapy or by altering the ability of major food allergens to interact with IgE antibodies through molecular biology methods. Strategies for developing any potentially successful food allergy immunotherapy for patients with life-long sensitivities must satisfy several requirements. First, these methods must be safe and provide an optimal risk-to-benefit ratio for the patient. Procedures must be cost effective and relatively easy to perform so that patients can be treated on a routine basis. In the ensuing discussion, we explore the mucosal immune response as it relates to food allergy, potential treatments of food-allergic individuals through alteration of the host immune responses, use of mucosal vaccines, and traditional and novel approaches to immunotherapy. Finally, genetic engineering and its use to alter allergenic protein molecules to reduce or abolish their allergenicity is discussed.