Cigarette smoking causes accumulation of polymorphonuclear leukocytes in alveolar septum

The polymorphonuclear leukocyte (PMN) may play an important role in the pathogenesis of emphysema. Cigarette smoking is associated with the accumulation of PMN in the lung as determined by bronchoalveolar lavage. We enumerated alveolar wall PMN on histologic sections from lungs of humans and hamsters with and without cigarette smoke exposure. In human non-smokers, there were 0.9 ± 0.2 PMN/mm alveolar wall. In cigarette smokers without emphysema, there were 2.1 ± 0.3 PMN/mm alveolar wall (p < 0.01), and in cigarette smokers with emphysema, there were 2.4 ± 0.7 PMN/mm alveolar wall (p < 0.05). There were 1.7 ± 0.3 PMN/mm alveolar wall in the lungs of hamsters unexposed to cigarette smoke compared with 3.1 ± 0.3 PMN/mm alveolar wall in smoke-exposed hamsters (p < 0.005). Although cigarette smoking causes PMN to accumulate within alveolar septa, the accumulation does not seem to be closely related to the development of emphysema. This suggests that additional or other factors are important in the pathogenesis of emphysema.