Pulmonary cell responses to inhaled cigarette smoke.

The effect of cigarette smoke on free lung cells and the histology of the respiratory epithelium in guinea pigs was studied in four- and eight-week inhalation experiments. The animals received four cigarettes daily in concentrated puffs of three to four seconds. Exposure caused an increase in the number of macrophages and leukocytes found in the lung. The degree of irritation in the trachea increased, as judged from the count and condition of the goblet cells. Smoke that had been passed through a Cambridge filter did not cause these effects. The effects could not be demonstrated in animals without upper respiratory infection (SPF). This study shows the importance of the particulate phase and infection for the development of pulmonary reactions to tobacco smoke exposure.