Smoking, immunity, and DNA damage
The normal lung of non-smokers contains alveolar macrophages as guardian residents. However, when tobacco smoke enters the lungs it triggers a dramatic influx of macrophages and neutrophils in the bronchi and pulmonary epithelia. Smoking directly exposes the epithelial tissue to at least 60 powerful chemical carcinogens with the potential to cause DNA damage to larynx, bronchi, and lung epithelial cells. The most common compounds in tobacco smoke are nicotine, formaldehyde, ammonia, carbon monoxide, carbon dioxide, benzopyrenes, tar, acetone, hydroxyquinone, cadmium, and nitrogen oxides (1).