Immunotoxicological Aspects of Food Allergy

Food allergy is an important health problem and an issue of growing relevance for toxicology. The characteristics of food allergy have been described elsewhere in this volume, and in other recent review articles (1, 2). Nevertheless, it is appropriate here to place the relevant toxicological imperatives in the context of clinical and immunological aspects of food allergy. An important consideration is one of classification. By definition, allergic diseases are driven by specific immune responses. This distinguishes food allergy from other forms of food intolerance. One working classification is to regard food allergy as one type of food intolerance; the definition of the latter being a reproducible adverse reaction to a specific food or food component that results from an allergic response (food allergy), or is due to other mechanisms including pharmacological effects and enzyme deficiencies (3). In most instances, food allergy is associated with specific IgE antibody responses, although it in some cases other immunological mechanisms may play a predominant role. The best example is gluten-sensitive enteropathy, or celiac disease, that is characterized by a cell-mediated immune response (3). In addition, food allergic reactions are sometimes manifest in the absence of detectable IgE antibody, one interpretation being that in such instances other immune mechanisms are causing the symptoms. However, some care is needed in drawing this conclusion. Confirmation that suspected food allergy is mediated by IgE antibody derives from measurement of specific IgE in serum and=or skin prick test reactivity; both of which assessments require that detectable levels of IgE antibody are available systemically. However, the results of recent investigations suggest that localized IgE responses (in the gastrointestinal [GI] tract) also may elicit allergic reactions. Patients with