A new look at the pathophysiology of asthma.

Episodes of asthma, characterized by bronchial hyper-responsiveness and airway obstruction, are usually reversible and can be mitigated or prevented by appropriate use of therapeutic agents to manage asthma attacks. This article will highlight the various forms of asthma, either chronic or induced, and review both the correlating environmental factors and the immune mechanisms that are now understood to drive the inflammatory processes in the airways of the affected individuals. A significant fraction of humans is genetically predisposed toward having a robust response to allergens, characterized by a strong immunoglobulin E response (termed atopy) that manifests as an asthmatic reaction to airborne allergens in these sensitized individuals. However, occupation chemicals, airborne particles, and common insect allergens at home can also elicit an asthmatic response in exposed individuals, regardless of whether they are genetically susceptible or not. The complex immune mechanisms and sequelae that are associated with, and probably causal to, acute and persistent asthma episodes indicate that an imbalanced immune system is the primary driving force underlying asthma. This article will discuss how a dysregulated immune system, if not controlled by proper and aggressive therapeutic regimens, leads to pathogenic infiltration of the lung by various pro-inflammatory cells and eventual remodeling of the airway tissues, compromising normal lung function and one's quality of life.