Carbon and hemosiderin-laden macrophages in sputum of traffic policemen exposed to air pollution

In this study, we evaluated (a) quantitative modifications of dust cells and siderocytes and (b) qualitative modifications (i.e., cellular changes and inflammatory infiltrate) in sputum of 164 traffic policemen occupationally exposed to environmental pollution in an urban area. Such modifications were correlated with time of exposure and smoking habits. Seventy-three (45%) of the policemen were smokers, and a control group of 119 nonexposed individuals (24% smokers) who resided in a rural district near Perugia, Italy, were examined. The sputa, which was collected for 3 d, were smeared on glass slides stained according to Papanicolaou's and Perl's methods. The mean numbers of dust cells in the sputa policemen and the rural population were 103.8 and 12.48, respectively (p < .0001). The numbers of dust cells were highest in policemen who smoked (relative risk = 3.95; p < .006). The mean numbers of siderocytes in policemen and the rural population were 0.99 and 5.31, respectively (not statistically significant, Mann-Whitney test). The difference between the number of subjects with hemosiderin-laden macrophages in traffic policemen and in the control group was small, but it was significant statistically (p < .004). In traffic policemen, it was related to smoking and time of exposure to air pollution, whereas in the control population it was related to heart-pulmonary diseases. In this study, we observed a synergistic effect between smoking and environmental pollution. In addition, less than 5 y of exposure can caused significantly increased (a) numbers of macrophages and (b) inflammatory infiltrate in sputa. The results of the cytological diagnosis revealed a statistically significant difference between policemen and the rural population (p < .001). The cytological exam of sputa and correlations with smoking within each population were not statistically significant. In conclusion, macrophage count in sputum is a sensitive and reproducible method for investigators to verify pulmonary changes that may be observed before they can be measured by functional tests.