Egg Allergy

Excerpt

The primary objective of the immune system is to determine and distinguish between “self” and “not-self.” In doing so, the immune system eliminates pathogenic agents before a serious disease can occur. Thus, a robust immune system plays a pivotal role in maintaining health. An impaired immune response is connected with inherent immunodeficiencies or pharmaceutical agents (such as steroids, or chemotherapeutic agents). On the other extreme, the body’s immune system can fail to distinguish between “self” and “not-self,” leading to the development of auto-antibodies directed against cells of the body. Food allergy is a pathology along this spectrum. It is not an immunodeficiency since the immune system is adequately functioning, but it is not an autoimmune disorder since the antibodies generated are directed towards antigens from a food source (and hence, “not-self”). The term “egg allergy” refers to an adverse immunological response to exposure to allergens found in egg white or egg yolk. It is the second most common food allergy in the United States after milk allergy .

The major components of the immune system involved with egg allergy are mast cells and basophils. These cells are types of polymorphonuclear leukocytes (PMN), a group which also consists of eosinophils and neutrophils. The traditional view considered basophils and mast cells as the same type of cell due to their functionality and histological appearance. The major distinction between the two types of cells are the respective locations of each type of cell (basophils are serum-based while mast cells are located in the connective tissues). Despite their similarity in function and histological appearance, it is now thought that basophils and mast cells are different cells due to their distinct hematopoietic lineages.

Mast cells and basophils possess granules that contain a variety of compounds that facilitate local inflammatory response. These compounds include heparin, histamine, leukotrienes (C4, D4, and E4), and chemotactic factors. The histamine and leukotriene release causes smooth muscle contraction while histamine additional promotes increased vascular permeability. The chemotactic factors are primarily eosinophilic and neutrophilic.