ABSTRACT
Allergic diseases are illnesses that arise out of the action of the immune system through its ability to recognize foreign substances and to mount an immune response whenever it encounters these substances. Most individuals elicit no detectable immune response to foods, although many healthy people have very low levels of circulating immunoglobulin G (IgG) antibodies to some foods with no clinical deleterious effect. Well-documented cases of food allergy are almost always attributable to immunoglobulin E (IgE) antibodies. The pathophysiology of allergic disease caused by IgE antibody rests on a firm scientific foundation. The concept of delayed food allergy mediated by non-IgE specific immune responses has been the subject of a number of studies, but to date only rare cases of illness associated with IgG antibodies to foods and presumptively ascribed to a serum sickness-like mechanism have been reported. The cytotoxic test for food allergy is predicated on the erroneous concept that allergy to foods may be manifested as leukocyte cytotoxicity.
