The Nature of Immunological Reaction in the Peripheral Airways of Cigarette Smokers
The influence of tobacco smoke on human health is still an important problem worldwide. Complex inflammatory processes and changes in the immune system are crucial in the pathogenesis of smoking related disorders like chronic obstructive lung disease (COPD), lung cancer, asthma, interstitial lung diseases (ILD) and atherosclerosis. The objective of this review is to present the alterations in the immune system in smokers. Discrete changes in peripheral blood of smokers may be found, such as leukocytosis and elevated proportion of T cells. However, the mainly affected system is the respiratory tract. In bronchial epithelium, metaplastic and dysplastic changes are accompanied by elevated expression of adhesion molecules and secretion of many proinflammatory cytokines. In the population of pulmonary macrophages, an elevated proportion of cells, changes in expression surface markers: CD14, CD54, CD11 and CD71 with impaired phagocytic and antigen presenting function were observed. The influence of tobacco smoke on the population of granulocytes results in elevated proportion of neutrophils and eosinophils and elevated concentration of the products of neutrophils: neutrophil elastase (NE), interleukin- 8 (IL-8) and tumor necrosis factor (TNFα). Tobacco smoke seems to alter the way of death of neutrophils from apoptosis to necrosis. On the other hand, an elevated expression of the receptors of apoptosis on lymphocytes was found. Cigarette smoke enhances the recirculation of lymphocytes, which results in the augmentation of activated and cytotoxic/ suppressor cells in the bronchial lumen. Smoking cessation is the most effective method of prophylaxis and treatment of diseases related to tobacco smoking. However, many immunological changes in smokers are not completely reversible after quitting smoking.
Keywords: Smoking, immunity, lung, macrophages, neutrophils, lymphocytes
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