Asthma and Allergy

This chapter provides an overview of allergic diseases, specifically asthma. Allergic diseases are traditionally referred to as immediate or type I hypersensitivity reactions with allergen-specific IgE as an important factor. However, it is also apparent that critical cellular elements such as T lymphocytes constitute a major pathogenesis factor in the development of allergic diseases and, in particular, asthma. Dendritic cells and molecules such as the T cell receptor, major histocompatibility complex molecules, and co-stimulatory molecules are all necessary for inducing an allergic T cell inflammatory response. Clinical laboratory tools in conjunction with a thorough history and physical examination are used to diagnose properly and manage patients with allergic disorders. At present there is no in vitro test that confirms the presence of clinically relevant allergic disease. Quantitative specific IgE antibody immunoassays and Immunological assay advancements in determining cross-reactivity versus co-sensitization are explained. A comparison between skin testing and allergen specific-IgE immunoassays is presented.