title: Lack of evidence for allergenic properties of coumarin in a fragrance allergy mouse model.
abstract: BACKGROUND
  There is controversy as to whether coumarin, an ingredient in cosmetics and fragrances, is a contact allergen involved in fragrance allergy. We recently showed that the purity of coumarin is a critical parameter for its allergenicity because coumarin preparations containing trace amounts of contaminants induced cell proliferation in the local lymph node (LN) assay whereas pure coumarin did not.
  
  
  OBJECTIVE
  In the present study, we analyzed the sensitizing properties of coumarin (purity > 99.9) and of dihydrocoumarin (DHC), in a recently developed model of fragrance allergy in mice.
  
  
  RESULTS
  DHC was able to prime T cells in LNs draining the sensitization skin site and to induce a typical allergic contact dermatitis (ACD) reaction upon challenge, confirming that DHC is endowed with moderate sensitizing properties. In contrast, no T-cell activation and no ACD responses were obtained following sensitization and challenge with coumarin.
  
  
  CONCLUSIONS
  These results confirm that pure coumarin is endowed with very weak sensitizing capacities, if any, and suggest that the presence of contaminants in coumarin preparations may account for the previously reported allergenic properties of coumarin.
authors.affiliation: Institut National de la Santé et de la Recherche Médicale (INSERM), U851, IFR 128, BioSciences Lyon-Gerland, Lyon F-69365, France.
authors.forename: Marc
authors.initials: M
authors.lastname: Vocanson
authors.forename: Magalie
authors.initials: M
authors.lastname: Valeyrie
authors.forename: Aurore
authors.initials: A
authors.lastname: Rozières
authors.forename: Anca
authors.initials: A
authors.lastname: Hennino
authors.forename: François
authors.initials: F
authors.lastname: Floc'h
authors.forename: Arielle
authors.initials: A
authors.lastname: Gard
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Nicolas
mesh_terms: D000818:Animals; D015704:CD4 Antigens / Q000276:immunology; D003374:Coumarins / Q000009:adverse effects* / Q000276:immunology; D017449:Dermatitis, Allergic Contact / Q000209:etiology* / Q000276:immunology; D004423:Ear / Q000473:pathology; D004797:Enzyme-Linked Immunosorbent Assay; D007371:Interferon-gamma / Q000378:metabolism; D023441:Local Lymph Node Assay; D008212:Lymphocyte Depletion; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D010476:Perfume / Q000009:adverse effects*; D013601:T-Lymphocytes / Q000276:immunology / Q000378:metabolism
chemical_list: D015704:CD4 Antigens; D003374:Coumarins; D010476:Perfume; D007371:Interferon-gamma; C030123:coumarin; C026308:3,4-dihydrocoumarin