Objectives There has been concern over the possible risk of autoimmune diseases from exposure to trichloroethylene (TCE), an industrial solvent and common pollutant near hazardous waste sites. Studies of TCE-exposed lupus-prone mouse strains have reported increases in serum antinuclear antibodies (ANAs), a marker of autoimmunity, and autoimmune pathologic changes, while epidemiologic studies have provided limited support for an association between TCE exposure and scleroderma. To investigate exposure-related biologic evidence of autoimmunity in humans, we measured ANA levels in sera from a cross-sectional study of TCE-exposed (n=80) and TCE-unexposed (n=96) workers in Guangdong, China.
Methods Full-shift personal air exposure measurements for TCE were taken prior to blood collection. Serum ANAs were detected by immunofluorescence on HEp-2 cells. We calculated ORs and 95% CI relating levels of TCE exposure (categorised using tertiles as cut-points) and ANA positivity (1+ intensity at 1:320 dilution) using multivariable logistic regression.
Results Samples from 16 of 176 participants were ANA-positive. We found higher levels of TCE exposure (concentrations>17.27 ppm) to be associated with an elevated odds of ANA positivity (OR 4.7, 95% CI 1.3 to 16.8) compared with unexposed controls. This association remained after excluding two subjects with diagnosed autoimmune disease (OR 4.5, 95% CI 1.2 to 16.2). We did not observe an association with ANAs at lower exposure levels.
Conclusions Our findings, to our knowledge the first direct human evidence of an association between TCE exposure and systemic autoimmunity, provide biologic plausibility to epidemiologic evidence relating TCE and autoimmune disease.
- Autoimmune Diseases
- Cross-Sectional Studies
Data availability statement
Data are available upon reasonable request.
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KDD, NR and QL contributed equally.
Contributors MP conceptualised the antinuclear antibody (ANA) investigation, conducted the data analysis and wrote the first draft of the paper. QL, NR, LZ and MTS designed the cross-sectional study. RV, CW, YH and XT conducted the study fieldwork and exposure assessment. WH and SIB organised study logistics for the ANA analysis. AAF-A and KDD oversaw the ANA laboratory analysis. JR contributed to the data analysis. All authors critically revised and approved the final version of this manuscript. QL, NR and KDD contributed equally to this paper.
Funding This project was supported by Intramural Research Program funding from the National Cancer Institute (Bethesda, Maryland, USA) and funding from the Department of Science and Technology of Guangdong Province, China (2007A050100004 to XT).
Competing interests None declared.
Provenance and peer review Not commissioned; externally peer reviewed.
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