Inflammatory indices for chronic bronchitis and chronic obstructive airway disease. Cell populations in bronchial and bronchoalveolar lavage

The development of chronic bronchitis (CB) and chronic obstructive airway disease (COAD) seems to be related to inflammatory changes of airway structure. However, the cause and the exact location and type of these changes resulting in altered airway function are not known. Mucosal inflammation is characterized by the recruitment of granulocytes, macrophages and lymphocytes as well as by the shedding of epithelial cells. The present chapter discusses the usefulness of bronchial lavage (BL; 50 ml of lavage volume) directly followed by bronchoalveolar lavage (BAL; 200 ml), for the characterization and quantification of inflammation in proximal and peripheral airways, respectively. On the basis of results from the literature and a pilot study on CB patients with or without coexisting COAD, the following conclusions may be drawn: There is a profound difference in lavage cell composition and numbers between non-smokers and smokers. However, within the group of smokers there are few additional changes in cell numbers and composition when concomitant airway disease is present. The obstruction of the COAD patients is correlated to a reduced recovery of BL and BAL fluid. Furthermore, these patients seem to have a reduced number of most cell types in their BL. This diminitution is not just related to the reduced fluid recovery. The BL cells have a lower viability and BL macrophages have a reduced phagocytic capacity when compared with matching BAL cells. The viability of cells was lowest in BL from the COAD group. These findings may suggest that COAD entails a reduced transport of macrophages to the small airways and/or an enhanced turnover of these cells in the bronchi. Functional studies of lavage cells may supply additional, and perhaps more specific, information on the mechanisms involved in the inflammatory process.