Benzo[a]pyrene diolepoxide-DNA adducts in alveolar macrophages of smokers

The presence of benzo[a]pyrene diolepoxide (BPDE)-DNA adducts was investigated by synchronous fluorescence spectrophotometry in cells recovered by bronchoalveolar lavage from 39 individuals. Pulmonary alveolar macrophages constituted, on average, 90% of these cells. No adduct was detected in samples from non-smokers or ex-smokers, whereas 84.6% of samples from current smokers exhibited typical fluorescence peaks. The samples from four subjects who had stopped smoking during the last 6 months were also positive. A considerable variability was observed in the intensity of signals, which in positive samples was significantly correlated with the number of cigarettes currently smoked but not with the cumulative total of cigarettes smoked during a lifetime. In any case, part of the recorded quantitative variations could not be ascribed to the daily number of cigarettes but probably depended on interindividual variability in smoking habits or in toxicokinetics and metabolism. On the whole, detection of BPDE-DNA adducts in alveolar macrophages, compared to other surrogate cell populations, appears to represent a sensitive and specific biomonitoring tool, assessing the internal dose of inhaled benzo[a]pyrene in the proximity of target cells of the respiratory tract. Exploitation of this end-point in molecular epidemiology and cancer prevention studies warrants further investigation.