Occupational exposure to trichloroethylene is associated with a decline in lymphocyte subsets and soluble CD27 and CD30 markers.
Occupational cohort and case-control studies suggest that trichloroethylene (TCE) exposure may be associated with non-Hodgkin lymphoma (NHL) but findings are not consistent. There is a need for mechanistic studies to evaluate the biologic plausibility of this association. We carried out a cross-sectional molecular epidemiology study of 80 healthy workers that used TCE and 96 comparable unexposed controls in Guangdong, China. Personal exposure measurements were taken over a three-week period before blood collection. Ninety-six percent of workers were exposed to TCE below the current US Occupational Safety and Health Administration Permissible Exposure Limit (100 p.p.m. 8 h time-weighted average), with a mean (SD) of 22.2 (36.0) p.p.m. The total lymphocyte count and each of the major lymphocyte subsets including CD4+ T cells, CD8+ T cells, natural killer (NK) cells and B cells were significantly decreased among the TCE-exposed workers compared with controls (P < 0.05), with evidence of a dose-dependent decline. Further, there was a striking 61% decline in sCD27 plasma level and a 34% decline in sCD30 plasma level among TCE-exposed workers compared with controls. This is the first report that TCE exposure under the current Occupational Safety and Health Administration workplace standard is associated with a decline in all major lymphocyte subsets and sCD27 and sCD30, which play an important role in regulating cellular activity in subsets of T, B and NK cells and are associated with lymphocyte activation. Given that altered immunity is an established risk factor for NHL, these results add to the biologic plausibility that TCE is a possible lymphomagen.
Division of Cancer Epidemiology and Genetics, National Cancer Institute, Bethesda, MD 20892-7240, USA. qingl@mail.nih.gov
Qing
Q
Lan
Luoping
L
Zhang
Xiaojiang
X
Tang
Min
M
Shen
Martyn T
MT
Smith
Chuangyi
C
Qiu
Yichen
Y
Ge
Zhiying
Z
Ji
Jun
J
Xiong
Jian
J
He
Boris
B
Reiss
Zhenyue
Z
Hao
Songwang
S
Liu
Yuxuan
Y
Xie
Weihong
W
Guo
Mark P
MP
Purdue
Noe
N
Galvan
Kerry X
KX
Xin
Wei
W
Hu
Laura E
LE
Beane Freeman
Aaron E
AE
Blair
Laiyu
L
Li
Nathaniel
N
Rothman
Roel
R
Vermeulen
Hanlin
H
Huang
D015415:Biomarkers / Q000378:metabolism*; D016022:Case-Control Studies; D006801:Humans; D017730:Ki-1 Antigen / Q000097:blood*; D018655:Lymphocyte Count; D016131:Lymphocyte Subsets / Q000187:drug effects*; D017720:Molecular Epidemiology; D016273:Occupational Exposure; D014241:Trichloroethylene / Q000009:adverse effects*; D018127:Tumor Necrosis Factor Receptor Superfamily, Member 7 / Q000097:blood*
D015415:Biomarkers; D017730:Ki-1 Antigen; D018127:Tumor Necrosis Factor Receptor Superfamily, Member 7; D014241:Trichloroethylene