Airway epithelial cells, cytokines, and pollutants

The airway epithelium is a complex physicochemical barrier that plays a piv otal role in host defense. Epithelial cells have been shown to be a rich so urce of several classes of modulatory compounds, of which the cytokines for m the largest group and possibly play the most important role in the etiolo gy of airway disease. Evidence suggests that there are differences in the a irway epithelial cells of individuals with and without respiratory disease, both with regard to (1) their capacity to express and release different ty pes and quantities of specific cytokines and (2) their reactivity to inhale d irritants. Consequently, it is tempting to speculate that differences in epithelial cell function are an Important determinant of the predisposition to respiratory disease. However, whether the differences are a result of a n intrinsic defect, an acquired property due to the disease process itself, or a combination of the two, remains to be determined. In view of advances that have been made in the understanding of the putative underlying mechan isms in airway diseases, it should be possible to formulate novel therapeut ic agents in the form of specific monoclonal antibodies directed against sp ecific proinflammatory cytokines.