title: Occupational exposure to diesel engine exhaust and alterations in lymphocyte subsets.
abstract: BACKGROUND
  The International Agency for Research on Cancer recently classified diesel engine exhaust (DEE) as a Group I carcinogen based largely on its association with lung cancer. However, the exposure-response relationship is still a subject of debate and the underlying mechanism by which DEE causes lung cancer in humans is not well understood.
  
  
  METHODS
  We conducted a cross-sectional molecular epidemiology study in a diesel engine truck testing facility of 54 workers exposed to a wide range of DEE (ie, elemental carbon air levels, median range: 49.7, 6.1-107.7 µg/m(3)) and 55 unexposed comparable controls.
  
  
  RESULTS
  The total lymphocyte count (p=0.00044) and three of the four major lymphocyte subsets (ie, CD4+ T cells (p=0.00019), CD8+ T cells (p=0.0058) and B cells (p=0.017)) were higher in exposed versus control workers and findings were highly consistent when stratified by smoking status. In addition, there was evidence of an exposure-response relationship between elemental carbon and these end points (ptrends<0.05), and CD4+ T cell levels were significantly higher in the lowest tertile of DEE exposed workers compared to controls (p=0.012).
  
  
  CONCLUSIONS
  Our results suggest that DEE exposure is associated with higher levels of cells that play a key role in the inflammatory process, which is increasingly being recognised as contributing to the aetiology of lung cancer.
  
  
  CONCLUSIONS
  This study provides new insights into the underlying mechanism of DEE carcinogenicity.
authors: Division of Cancer Epidemiology and Genetics, National Cancer Institute, Rockville, Maryland, USA.
authors: Qing
authors: Q
authors: Lan
authors: Institute for Risk Assessment Sciences, Utrecht University, Utrecht, The Netherlands.
authors: Roel
authors: R
authors: Vermeulen
authors: Key Laboratory of Chemical Safety and Health, National Institute of Occupational Health and Poison Control, Chinese Center for Disease Control and Prevention, Beijing, China.
authors: Yufei
authors: Y
authors: Dai
authors: Chaoyang Center for Disease Control and Prevention, Chaoyang, China.
authors: Dianzhi
authors: D
authors: Ren
authors: Division of Cancer Epidemiology and Genetics, National Cancer Institute, Rockville, Maryland, USA.
authors: Wei
authors: W
authors: Hu
authors: Key Laboratory of Chemical Safety and Health, National Institute of Occupational Health and Poison Control, Chinese Center for Disease Control and Prevention, Beijing, China.
authors: Huawei
authors: H
authors: Duan
authors: Key Laboratory of Chemical Safety and Health, National Institute of Occupational Health and Poison Control, Chinese Center for Disease Control and Prevention, Beijing, China.
authors: Yong
authors: Y
authors: Niu
authors: Hong Kong University, Hong Kong, Hong Kong.
authors: Jun
authors: J
authors: Xu
authors: Chaoyang Center for Disease Control and Prevention, Chaoyang, China.
authors: Wei
authors: W
authors: Fu
authors: Institute for Risk Assessment Sciences, Utrecht University, Utrecht, The Netherlands.
authors: Kees
authors: K
authors: Meliefste
authors: China Medical University, Shenyang, China.
authors: Baosen
authors: B
authors: Zhou
authors: Chaoyang Center for Disease Control and Prevention, Chaoyang, China.
authors: Jufang
authors: J
authors: Yang
authors: Key Laboratory of Chemical Safety and Health, National Institute of Occupational Health and Poison Control, Chinese Center for Disease Control and Prevention, Beijing, China.
authors: Meng
authors: M
authors: Ye
authors: Key Laboratory of Chemical Safety and Health, National Institute of Occupational Health and Poison Control, Chinese Center for Disease Control and Prevention, Beijing, China.
authors: Xiaowei
authors: X
authors: Jia
authors: Key Laboratory of Chemical Safety and Health, National Institute of Occupational Health and Poison Control, Chinese Center for Disease Control and Prevention, Beijing, China.
authors: Tao
authors: T
authors: Meng
authors: Key Laboratory of Chemical Safety and Health, National Institute of Occupational Health and Poison Control, Chinese Center for Disease Control and Prevention, Beijing, China.
authors: Ping
authors: P
authors: Bin
authors: Division of Cancer Epidemiology and Genetics, National Cancer Institute, Rockville, Maryland, USA.
authors: Christopher
authors: C
authors: Kim
authors: Division of Cancer Epidemiology and Genetics, National Cancer Institute, Rockville, Maryland, USA.
authors: Bryan A
authors: BA
authors: Bassig
authors: Division of Cancer Epidemiology and Genetics, National Cancer Institute, Rockville, Maryland, USA Division of Epidemiology, Albert Einstein College of Medicine, New York, New York, USA.
authors: H Dean
authors: HD
authors: Hosgood
authors: Division of Cancer Epidemiology and Genetics, National Cancer Institute, Rockville, Maryland, USA.
authors: Debra
authors: D
authors: Silverman
authors: Key Laboratory of Chemical Safety and Health, National Institute of Occupational Health and Poison Control, Chinese Center for Disease Control and Prevention, Beijing, China.
authors: Yuxin
authors: Y
authors: Zheng
authors: Division of Cancer Epidemiology and Genetics, National Cancer Institute, Rockville, Maryland, USA.
authors: Nathaniel
authors: N
authors: Rothman
mesh_terms: D000328:Adult; D000395:Air Pollutants, Occupational / Q000032:analysis; D001402:B-Lymphocytes / Q000378:metabolism*; D015496:CD4-Positive T-Lymphocytes / Q000378:metabolism; D018414:CD8-Positive T-Lymphocytes / Q000378:metabolism; D002244:Carbon / Q000032:analysis; D002273:Carcinogens / Q000032:analysis; D003430:Cross-Sectional Studies; D006801:Humans; D007249:Inflammation / Q000209:etiology / Q000378:metabolism; D008175:Lung Neoplasms / Q000209:etiology* / Q000378:metabolism; D016131:Lymphocyte Subsets / Q000378:metabolism*; D008875:Middle Aged; D018986:Motor Vehicles; D016273:Occupational Exposure / Q000009:adverse effects* / Q000032:analysis; D018570:Risk Assessment; D013601:T-Lymphocytes / Q000378:metabolism*; D001335:Vehicle Emissions / Q000032:analysis
chemical_list: D000395:Air Pollutants, Occupational; D002273:Carcinogens; D001335:Vehicle Emissions; D002244:Carbon
keywords: Diesel; lymphocyte subset; occupational exposure; toxicity