Benzo(a)pyrene diol-epoxide-DNA adduct levels and aryl hydrocarbon hydroxylase (AHH) in human white blood cells from smokers and non-smokers

Benzo(a)pyrene diol-epoxide (BPDE)-DNA adducts and aryl hydrocarbon hydroxylase (AHH) activity were determined in white blood cells (WBCs) obtained from non-smokers, ex-smokers and smokers. DNA adduct levels ranged from non-detectable (ND) to 8.8 per 10 8 nucleosides in all samples analysed. The mean level in WBC from smokers (1.93±0.55 mean±SE) was similar to that from non-smokers (1.18±0.40) and ex-smokers (1.83±0.50). The distribution frequency of AHH activity in non-smokers was different from that in smokers, while 50% of non-smokers had AHH activity ranging from ND to 20 fmol mg -1 min -1 , This low AHH activity was not found in smokers; no correlation was found between AHH activity and tobacco consumption (r=0.097; P = 0.76; n=12). On the contrary, AHH activity was correlated with BPDE-DNA adduct levels in WBCs from the same subjects (r=0.457; P=0.019; n=26). Our findings indicate that there are limitations to the use of WBCs as surrogate cells for determining internal PAH exposure in target organs.