, immune toxicity and neurotoxicity 3,4) . Immune cell apoptosis is one of the hot spots in immune toxicity research, and peripheral blood mononuclear cell (PBMC) apoptosis can reflect the immune system's stability. Reduced apoptosis would result in excessive proliferation of immune cells and formation of autoimmunity, while increased apoptosis can cause immunodeficiency and formation of immune tolerance 5) . To assess the immune function of coke oven workers, we detected and analyzed the changes in PBMC apoptosis.
Subjects and Methods
SubjectsThe exposed groups consisted of 129 middle-school educated, 23-49-year-old male coke oven workers employed at least 1 year in the coke plant of a large state-owned company, who were divided into the oven-bottom group (34 subjects), oven-side group (48 subjects) and oven-top group (47 subjects) according to their working sites and environmental monitoring data. A working shift lasted 8 h, and each worker's tasks were relatively constant over 1 yr. The controls were 37 warehouse workers from the raw materials plant at same company who were not occupationally exposed to PAHs from the coking operation and had not visited the coke plant in the previous 3 mo, were The aim of the present study was to determine the peripheral blood mononuclear cell (PBMC) apoptosis in coke oven workers so that we can take effective measures to protect coke oven workers. Methods: The subjects, 129 coke oven workers and 37 warehouse workers (controls), were investigated using a questionnaire to collect information about their age, working years, smoking and drinking habits, vocational history and other general information. The coke oven workers were divided into the oven-bottom group (34), oven-side group (48) and oven-top group (47) according to their working sites and environmental monitoring data. The concentration of benzo[a]pyrene (B[a]P) and the subjects' urinary 1-hydroxypyrene (1-OH-Py) levels were determined by HPLC. Additionally, the PBMCs were separated from blood samples, and the early and late apoptosis rates were determined by flow cytometry. Results: The airborne B[a]P concentrations were 19.5 ± 13.2, 185.9 ± 38.6 and 1,623.5 ± 435.8 ng/m 3 at the bottom, side and top of the oven, respectively, and were higher than in the controls' workplaces 10.2 ± 7.6 ng/m 3 . Urinary 1-OH-Py, indicating the B[a]P's internal exposure level, was significantly higher in the exposed groups than in the controls (p<0.05). Compared with the controls, the coke oven workers' PBMC apoptosis rates were significantly increased and increased in association with the B[a]P level. PBMC apoptosis increased in association with the 1-OH-Py level and coking operation years and decreased in association with years of alcohol consumption. Conclusions: PBMC apoptosis in the coke oven workers was associated with the 1-OH-Py level, coke operation years and
