Immunopathogenesis of bronchial asthma.

Bronchial asthma is a common immune-mediated disorder characterized by reversible airway inflammation, mucus production, and variable airflow obstruction with airway hyperresponsiveness. Allergen exposure results in the activation of numerous cells of the immune system, of which dendritic cells (DCs) and Th2 lymphocytes are of paramount importance. Although the epithelium was initially considered to function solely as a physical barrier, it is now evident that it plays a central role in the Th2-cell sensitization process due to its ability to activate DCs.