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 an d 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 we re correlated with time of exposure and smoking habits. Seventy-three (45%) of the policemen were smokers, and a control group of 119 nonexposed indiv iduals (24% smokers) who resided in a rural district near Perugia, Italy, w ere 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 nu mbers of dust cells in the sputa policemen and the rural population were 10 3.8 and 12.48, respectively (p < .0001). The numbers of dust cells were hig hest in policemen who smoked (relative risk = 3.95; p < .006). The mean num bers of siderocytes in policemen and the rural population were 0.99 and 5.3 1, respectively (not statistically significant, Mann-Whitney test). The dif ference between the number of subjects with hemosiderin-laden macrophages i n traffic policemen and in the control group was small, but it was signific ant statistically (p < .004). In traffic policemen, it was related to smoki ng 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 s ynergistic effect between smoking and environmental pollution. In addition, less than 5 y of exposure can caused significantly increased (a) numbers o f macrophages and (b) inflammatory infiltrate in sputa. The results of the cytological diagnosis revealed a statistically significant difference betwe en policemen and the rural population (p < .001). The cytological exam of s puta and correlations with smoking within each population were not statisti cally 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.