The pathology of asthma: brief review.

The presence of chronic airway inflammation in asthmatic patients has been known for over a century, but the relationship of this inflammatory process to the pathogenesis of reversible airflow obstruction and non-specific bronchial hyperresponsiveness remains unclear. In recent years, the increasing ability to sample the lower respiratory tract of living asthmatic patients, coupled with revolutionary advances in immunology and molecular biology, has resulted in extensive evaluation of inflammatory cells and mediators implicated in the pathogenesis of asthma. In addition, there is increasing recognition that airway remodeling, characterized by thickening of all compartments of the airway wall, may have profound consequences on the mechanics of airway narrowing in asthma and contribute to the chronicity and progression of the disease. In this brief review, I will describe the gross and microscopic pathology of asthma, the process of airway remodeling and its functional consequences, and speculate on future directions to improve our understanding of the structural changes of asthma and their pathogenic role.