The Immunology of Asthma and Allergic Rhinitis

The immune system is a complex collection of cells, tissues, and chemical mediators positioned throughout the body, whose primary purpose is to protect us against infection. However, its function is not only fundamental in protection from infectious disease but also provides aberrant response in allergens such as with asthma and allergic rhinitis. Allergic diseases like asthma and allergic rhinitis are characterized by a distinct type of inflammatory response, driven by immunoglobulin E (IgE)-dependent mechanisms. In asthma and allergic rhinitis, the inflammatory response is mediated by interaction of several immune cells (monocytes, lymphocytes, and polymorphonuclear cells) and cellular chemical mediators. In particular, atopic allergic response leads to destruction of multiple target cells such as epithelial, parenchymal and vascular and connective tissue of the airways. In addition, in inflammatory response in asthma and allergic rhinitis, sensory nerves are sensitized, leading to clinical manifestations. Sneezing and coughing are hypersensitivity responses of sensory nerves in allergic rhinitis and asthma, respectively. Similarly, nasal congestion and discharge in allergic rhinitis are due to vasodilatation that leads to plasma exudates as well as mucous secretion. The allergic inflammatory response is regulated by several transcription factors, particularly nuclear factor-κb (NF-κB), GATA-3 protein 3, and GATA binding protein.