ABSTRACT
The processes that result in reversible narrowing of the airways in asthma remain partially de¢ned but are clearly associated with chronic in£ammation in and around the bronchi. In the majority of cases, these are associated with aberrant immunological responses to otherwise innocuous substances, such as pollens, animal danders, and mite proteins. Both environmental and genetic factors have been implicated in the genesis of allergic hypersensitivity in asthma. In the context of this chapter, these issueswill be discussed primarily in relation to their possible roles in the induction of ‘‘asthmagenic’’ T-cell responses.
