Nasal Allergies: Natural Approaches for the Prevention and Treatment of Allergic Rhinitis

Th e allergic response is best characterized as a specifi c infl ammatory response of the immune system against environmental agents that contact the skin or mucosa. Th e primary immune cells involved in allergic responses are IgEreceptor positive mast cells (embedded within tissues) and basophils (circulating in the plasma).3 When an allergen crosslinks two or more IgE antibodies connected to a mast cell, a cascade of signals triggers the mast cell to immediately respond with a variety of infl ammatory processes. Th e fi rst, and most notable, is the release of preformed substances from granules within the mast cell. Th is process, known as degranulation, releases substances such as histamine, heparin, tryptase and several infl ammatory cytokines into the surrounding tissues. Likewise, mast cells also begin to synthesize other infl ammatory mediators such as pro-infl ammatory cytokines (IL-1, IL-6), TNFα, as well as pro-infl ammatory prostaglandins and leukotrienes. Th ese substances lead to capillary permeability, edema, chemo-attraction of more immune cells, vasodilation, and pain. Prevention of this allergic reaction requires some understanding of the process that leads to mast cell destabilization and degranulation. Th e cross-linking of the IgE receptors on mast cells by antigen-bound immunoglobulin E (IgE) triggers a very complex set of biochemical events that leads to membrane destabilization and degranulation, as well as the synthesis and secretion of cytokines, enzymes and transcripton factors (See Figures 2 and 3).4,5,6 As with most receptor-mediated pathways, the initial step involves the phosphorylation of the receptor itself, followed by a cascade of secondary signals; mostly signaled through additional phosphorylation reactions. Key among the steps is the formation of inositol-triphosphate (IP3), which mediates the initial release of calcium from intracellular stores. Th is is followed by an infl ux Nasal Allergies: Natural Approaches for the Prevention and Treatment of Allergic Rhinitis. Volume 8, No. 1