title: Investigation of diethylthiourea and ethyl isothiocyanate as potent skin allergens in chloroprene rubber.
abstract: BACKGROUND
  Exposure to chloroprene rubber has resulted in numerous cases of allergic contact dermatitis, attributed to organic thiourea compounds used as vulcanization accelerators. However, thiourea compounds are not considered to be strong haptens.
  
  
  OBJECTIVE
  To analyse common commercial chloroprene materials for their contents of diethylthiourea (DETU), dibutylthiourea (DBTU), diphenylthiourea (DPTU), and their degradation products, isothiocyanates; and to investigate the sensitization potencies of possible degradation products of the mentioned thiourea compounds.
  
  
  METHODS
  Liquid chromatography/mass spectrometry (MS) was used for quantification of organic thiourea compounds in chloroprene products, such as medical, sports and diving gear; isothiocyanates were measured by solid-phase microextraction/gas chromatography/MS. Sensitization potencies were determined with the murine local lymph node assay (LLNA).
  
  
  RESULTS
  DETU was identified at concentrations of 2.7-9.4 µg/cm(2) in all samples, whereas neither DBTU nor DPTU was detected. At 37°C, degradation of DETU in the materials to ethyl isothiocyanate (EITC) was detected. EITC and ethyl isocyanate showed extreme and strong sensitization potencies, respectively, in the LLNA.
  
  
  CONCLUSIONS
  DETU can act as a prehapten, being degraded to EITC when subjected to body temperature upon skin contact. EITC could thus be the culprit behind allergic contact dermatitis caused by chloroprene rubber.
authors.affiliation: Department of Analytical Chemistry, Stockholm University, Svante Arrhenius väg 16, SE-106 91, Stockholm, Sweden.
authors.forename: Ahmad G
authors.initials: AG
authors.lastname: Ramzy
authors.forename: Lina
authors.initials: L
authors.lastname: Hagvall
authors.forename: Mansoureh N
authors.initials: MN
authors.lastname: Pei
authors.forename: Kristin
authors.initials: K
authors.lastname: Samuelsson
authors.forename: Ulrika
authors.initials: U
authors.lastname: Nilsson
mesh_terms: D000485:Allergens / Q000032:analysis* / Q000276:immunology; D017449:Dermatitis, Allergic Contact / Q000209:etiology*; D006801:Humans; D017879:Isothiocyanates / Q000032:analysis* / Q000276:immunology; D023441:Local Lymph Node Assay; D009387:Neoprene / Q000737:chemistry*; D013890:Thiourea / Q000031:analogs & derivatives* / Q000032:analysis / Q000276:immunology
chemical_list: D000485:Allergens; D017879:Isothiocyanates; C035318:diethylthiourea; C034546:1,3-dibutyl-2-thiourea; C039155:ethyl isothiocyanate; D009387:Neoprene; C032788:diphenylthiourea; D013890:Thiourea
keywords: chloroprene; contact dermatitis; diethylthiourea; ethyl isothiocyanate; exposure analysis; local lymph node assay; neoprene; rubber chemicals