Mechanisms of allergic occupational asthma

Abstract

High-molecular-weight agents are a major cause of allergic occupational asthma in the workplace. High-molecular-weight agents comprise proteins from plant, microorganism or animal origin in the 10-60 kDa range. A few occupational asthma allergens are man-made chemicals such as isocyanates or acid anhydrides. Allergens with a major public health relevance are derived from flour, latex, enzymes and laboratory animals. The structures of antigenic determinants and mechanisms of many occupational allergens have been elucidated, whereas those of others, e.g. of platinum, recognized by immunocompetent cells are still obscure. The underlying immune mechanisms of allergic occupational asthma correspond to type I allergy, i.e., antigen recognition and processing by antigen-presenting cells, induction of the Th2 immune response resulting in the production of antigen-specific IgE antibodies, and finally release and generation of bronchospastic and inflammatory mediators by mast and other cells. The pathological mechanisms of allergic and non-allergic occupational asthma are relevant to diagnostics, management, and prevention, and are also briefly covered in this chapter. Related to this chapter is a useful listing of know occupational allergens, of high and low molecular weight, included in an Appendix.