Trichloroethylene Hypersensitivity Syndrome Is Potentially Mediated through Its Metabolite Chloral Hydrate

PLoS One. 2015 May 28;10(5):e0127101. doi: 10.1371/journal.pone.0127101. eCollection 2015.

Abstract

Background: We documented previously the entity of trichloroethylene (TCE) hypersensitivity syndrome (THS) in occupational workers.

Objectives: 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.

Publication types

  • Clinical Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Allergens* / adverse effects
  • Allergens* / pharmacokinetics
  • Chloral Hydrate* / adverse effects
  • Chloral Hydrate* / pharmacokinetics
  • Drug Hypersensitivity / etiology*
  • Drug Hypersensitivity / metabolism*
  • Female
  • Humans
  • Male
  • Middle Aged
  • Occupational Exposure / adverse effects*
  • Trichloroethylene* / adverse effects
  • Trichloroethylene* / pharmacokinetics

Substances

  • Allergens
  • Trichloroethylene
  • Chloral Hydrate

Grants and funding

This study was supported by the Guangdong Provincial Key Laboratory of Occupational Disease Prevention and Treatment (2012A061400007) and the National Key Technology Research, Development Program of the Ministry of Science and Technology of China during the 12th Five-Year Plan Period (2014BAI12B01) and Guangdong Medical Science Foundation (A2014071). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.