The predominant cellularity in most nonsmoking asth- matic phenotypes is the high percentage of eosinophils. The increase in mast cells and neutrophils detected in bronchial washings demonstrates the action of pro- inflammatory agents present in cigarette smoke on the airways of an asthmatic subject [27]. The role of smok- ing in the structure of the peripheral airways of asth- matic smokers is now being recognized [28, 29]. There are significant differences in the metabolism of arachi- donic acid in the lipoxygenase or cyclooxygenase routes in smokers compared with never-smokers [30].
Environmental air contamination caused by cigarette smoke has deleterious effects on nonsmoking asthmatics. This contamination is associated with poorer quality of life, worse lung function, increased frequency of rescue medication and more visits to emergency rooms and hos- pitalizations [30].