ABSTRACT
Individuals are routinely exposed to various environmental allergens including house dust mite, animal dander, molds, and pollen. Although most individuals respond to allergen exposure without triggering a debilitating inflammatory response in the lung, some individuals develop an allergic immune response that can cause asthma. The physiological mechanisms that mediate whether an individual responds to an allergen in a “normal” or asthmatic fashion remain poorly understood. However, evidence suggests that the nature of the response to allergen is related to the underlying T-helper (Th) cell cytokine response (reviewed in Reference 1 and 2). Asthma is currently defined as a chronic inflammatory (Th2-mediated) disease of the lung. Normal individuals respond to inhaled allergen through a Th1-mediated cytokine response (interleukin [IL-2] and interferon [IFN]-
γ
) which is critical in the development of cell-mediated immunity.
