Bronchoscopic airway sampling for investigational purposes has also yielded important insights regarding the pathogenesis of asthma and related airway disorders. Bronchoalveolar lavage (BAL) and endobronchial brush biopsies have emerged as the most widely used invasive research tools to assess inflammation and tissue remodeling in airway and interstitial lung diseases. Such procedures allow airway inflammatory and epithelial cells, proteins and other molecules of interest to be isolated in vivo in a manner that is critical to understanding the complex nature of asthma and other airway disorders. Numerous reports have attested to the safety of bronchoscopy including BAL and brush biopsy; these reports have been reviewed recently in a joint publication between the NHLBI and NIAID. So not only is bronchoscopic airway sampling important scientifically, but it is considered appropriate for research use in normal and asthmatic subjects.