Desensitization therapy for allergy: theory and practice Essay

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Allergies are one of the most common complaints for which patients seek medical attention. They disrupt patients’ lives and can even make others uncomfortable. While symptomatic relief can be obtained with antihistamines and similar medications, most patients would rather live completely symptom free and thus they turn to desensitization therapy. Here, I will explain the mechanism behind allergies and the different forms of desensitization therapies that are available today.
An allergy is a hypersensitivity reaction by the immune system that occurs to certain antigens for which the body perceives as a threat and has an overreaction to. Patients generally experience inflammation of the airways, among other symptoms caused by the
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The APC’s, when activated, migrate to the lymph nodes and interact with T and B cells to initiate the immune response. Antigens gets broken down to peptide fragments and presented on the cell surface by major histocompatibility complex 2 molecules (MHC-II) to T cell receptors. For this reaction to be significant, a co-stimulatory signal is also needed to increase interleukin-2 (IL-2) production. IL-2 is a T cell growth factor that is necessary for T cell activation. When T cells are activated the Th2 cytokines are produced. In particular, IL-4 causes CD4+ cells to adopt Th2 properties and stimulates B and T cell proliferation, along with the upregulation of MHC-II expression. IL-4 also causes B cells to undergo class switching and produce IgE that is specific to the allergen. The IgE binds to the Fc receptors on mast cells and basophils and upon re-exposure to the allergen, mediators, mainly histamine, leukotrienes, and cytokines, are released from preformed granules in the cell.4 Another cytokine, IL-5, activates eosinophils and has a stimulatory role on B cell growth. Eosinophils, along with neutrophils, basophils, T cells, and macrophages produce more cytokines and inflammatory mediators, which keeps the inflammatory response active. This is known as the late phase of an allergic reaction, which is responsible for the persistent chronic symptoms of allergies. Chronic symptoms include swelling of the nasal
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