title: Trichloroethylene Hypersensitivity Syndrome Is Potentially Mediated through Its Metabolite Chloral Hydrate.
abstract: BACKGROUND
  We documented previously the entity of trichloroethylene (TCE) hypersensitivity syndrome (THS) in occupational workers.
  
  
  OBJECTIVE
  To identify the culprit causative compound, determine the type of hypersensitivity of THS, and establish a screening test for subjects at risk of THS.
  
  
  METHODS
  TCE and its main metabolites chloral hydrate (CH), trichloroethanol (TCOH) and trichloroacetic acid (TCA) were used as allergens at different concentrations in skin patch tests. The study included 19 case subjects diagnosed with occupational THS, 22 control healthy workers exposed to TCE (exposure >12 weeks), and 20 validation new workers exposed to TCE for <12 weeks free of THS. All subjects were followed-up for 12 weeks after the patch test.
  
  
  RESULTS
  The highest patch test positive rate in subjects with THS was for CH, followed by TCOH, TCA and TCE. The CH patch test positive rate was 100% irrespective of CH concentrations (15%, 10% and 5%). The TCOH patch test positive rate was concentration-dependent (89.5%, 73.7% and 52.6% for 5%, 0.5% and 0.05%, respectively). Lower patch test positive rates were noted for TCA and TCE. All patch tests (including four allergens) were all negative in each of the 22 control subjects. None of the subjects of the validation group had a positive 15% CH patch test.
  
  
  CONCLUSIONS
  Chloral hydrate seems to be the culprit causative compound of THS and type IV seems to be the major type of hypersensitivity of THS. The CH patch test could be potentially useful for screening workers at risk of THS.
authors.affiliation: Department of Occupational Health and Occupational Medicine, School of Public Health and Tropical Medicine, Southern Medical University, Guangzhou, Guangdong, 510505, PR China; Department of Occupational Medicine, Guangdong Province Hospital for Occupational Disease Prevention and Treatment, Guangzhou, Guangdong, 510300, PR China.
authors.forename: Yongshun
authors.initials: Y
authors.lastname: Huang
authors.affiliation: Department of Occupational Medicine, Guangdong Province Hospital for Occupational Disease Prevention and Treatment, Guangzhou, Guangdong, 510300, PR China.
authors.forename: Lihua
authors.initials: L
authors.lastname: Xia
authors.affiliation: Department of Occupational Medicine, Guangdong Province Hospital for Occupational Disease Prevention and Treatment, Guangzhou, Guangdong, 510300, PR China.
authors.forename: Qifeng
authors.initials: Q
authors.lastname: Wu
authors.affiliation: Department of Occupational Medicine, Guangdong Province Hospital for Occupational Disease Prevention and Treatment, Guangzhou, Guangdong, 510300, PR China.
authors.forename: Zifang
authors.initials: Z
authors.lastname: Zeng
authors.affiliation: Department of Occupational Medicine, Guangdong Province Hospital for Occupational Disease Prevention and Treatment, Guangzhou, Guangdong, 510300, PR China.
authors.forename: Zhenlie
authors.initials: Z
authors.lastname: Huang
authors.affiliation: Department of Occupational Medicine, Guangdong Province Hospital for Occupational Disease Prevention and Treatment, Guangzhou, Guangdong, 510300, PR China.
authors.forename: Shanyu
authors.initials: S
authors.lastname: Zhou
authors.affiliation: Department of Occupational Medicine, Guangdong Province Hospital for Occupational Disease Prevention and Treatment, Guangzhou, Guangdong, 510300, PR China.
authors.forename: Jiachun
authors.initials: J
authors.lastname: Jin
authors.affiliation: Department of Occupational Health and Occupational Medicine, School of Public Health and Tropical Medicine, Southern Medical University, Guangzhou, Guangdong, 510505, PR China; Department of Occupational Medicine, Guangdong Province Hospital for Occupational Disease Prevention and Treatment, Guangzhou, Guangdong, 510300, PR China.
authors.forename: Hanlin
authors.initials: H
authors.lastname: Huang
mesh_terms: D000328:Adult; D000485:Allergens / Q000009:adverse effects / Q000493:pharmacokinetics; D002697:Chloral Hydrate / Q000009:adverse effects / Q000493:pharmacokinetics; D004342:Drug Hypersensitivity / Q000209:etiology* / Q000378:metabolism*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016273:Occupational Exposure / Q000009:adverse effects*; D014241:Trichloroethylene / Q000009:adverse effects / Q000493:pharmacokinetics
chemical_list: D000485:Allergens; D014241:Trichloroethylene; D002697:Chloral Hydrate