title: [One-year continuous observation of change in peripheral T cell subsets in workers exposed to low levels of benzene].
abstract: OBJECTIVE
  To observe the T cell subsets and blood cells in the peripheral blood of workers exposed to low levels of benzene for one year, and to investigate the relationship between T cell function impairment and benzene-induced hematopoietic injury after benzene exposure.
  
  
  METHODS
  Eighty-eight workers (58 males and 30 females, aged 18 ∼ 22 years) who just began to work in the workshop of a paint factory with exposure to benzene in Guangzhou, China were assigned to experimental group, and 88 workers (58 males and 30 females, aged 18 ∼ 25 years) who worked in the workshop without exposure to benzene were selected as controls. The blood samples of the workers were examined once every 4 months to measure the percentages of peripheral T cell subsets and peripheral blood cell counts in the one-year study. The benzene concentrations at operation points were also measured.
  
  
  RESULTS
  The peripheral blood cell counts in the benzene-exposed workers had no significant changes in the first and second examinations; the white blood cell (WBC) counts in the experimental group in the third and fourth examinations were significantly lower than that in the control group [(6.4 ± 3.0)×10(9)/L and (6.3 ± 2.7)×10(9)/L vs (7.3 ± 3.0)×10(9)/L, P < 0.05], and the platelet (PLT) count in the experimental group in the fourth examination was also significantly lower than that in the control group[(179 ± 74)×10(9)/L vs (189 ± 70)×10(9)/L, P < 0.05]. Compared with those in the control group (CD4+: 54.29 ± 12.78%, CD8+: 37.25 ± 12.30%), the percentage of CD3+ T cells in the experimental group increased in the third examination; the percentage of CD4+ T cells in the experimental group decreased continuously in the second, third, and fourth examinations (50.77 ± 11.05%, 45.40 ± 9.41%, and 41.27 ± 10.62%), while the percentage of CD8+ T cells in the experimental group kept increasing (46.07 ± 10.18%, 50.36 ± 10.62%, and 56.40 ± 9.41%) (P < 0.05).
  
  
  CONCLUSIONS
  The change in T cell subsets precedes that in the blood system in the workers exposed to low levels of benzene.
authors.affiliation: Guangzhou 12th Municipal People's Hospital, Guangzhou 510620, China.
authors.forename: Jia-yu
authors.initials: JY
authors.lastname: Chen
authors.forename: Wei
authors.initials: W
authors.lastname: Yu
authors.forename: Wei-wei
authors.initials: WW
authors.lastname: Liu
authors.forename: Bo
authors.initials: B
authors.lastname: Li
authors.forename: Yang-qiu
authors.initials: YQ
authors.lastname: Li
authors.forename: Li-jian
authors.initials: LJ
authors.lastname: Yang
authors.forename: Shao-hua
authors.initials: SH
authors.lastname: Chen
mesh_terms: D000293:Adolescent; D000328:Adult; D001554:Benzene / Q000009:adverse effects*; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D018655:Lymphocyte Count; D008297:Male; D016273:Occupational Exposure / Q000009:adverse effects*; D016176:T-Lymphocyte Subsets / Q000166:cytology*; D055815:Young Adult
chemical_list: D001554:Benzene