[Etiology of chronic bronchitis].

From a synopsis of the large number of epidemiological studies of the recent 20 years it is know, that inhalation of cigarette smoke is the most important factor that generates chronic bronchitis. Other noxious agents about which there are still controversial opinions, are air pollution and occupational inhalants. Although hypersecretion of mucus is the primary symptom of chronic bronchitis, it seems to have no particular prognostic meaning. Whether severe airflow obstruction develops, apparently depends upon predisposing factors such as disturbances of humoral immunity manifested by marked hypogammaglobulinemia or a defect of mucociliary clearance. In recent time increased serum IgE-levels in mom-atopic smokers with bronchial obstructions were reported. Frequent recurrent bronchial infections alone seem to be no serious risk factor. The molecular mechanisms that lead to structural damage are clarified. Activated alveolar macrophages attract polymorphonuclear leucocytes by chemotaxis. These cells set free proteolytic enzymes such as elastases. In addition certain oxidants inhibit the protection system of proteinase inhibitors.