title: Molecular features determining lymphocyte reactivity in allergic contact dermatitis to chloramphenicol and azidamphenicol.
abstract: BACKGROUND
  We report on two cases of allergic contact dermatitis to chloramphenicol and azidamphenicol respectively, with in vivo and in vitro lymphocyte reactivity to both compounds. The molecular features determining lymphocyte reactivity were explored because chloramphenicol, azidamphenicol, and thiamphenicol exhibit almost identical chemical structures.
  
  
  METHODS
  With chloramphenicol, azidamphenicol, and the chemically related thiamphenicol, we performed patch tests and lymphocyte transformation tests with both patients. Furthermore, the interleukin-5 and interferon-gamma concentrations in the cultures of peripheral blood mononuclear cells of one patient were determined.
  
  
  RESULTS
  Patch tests showed delayed hypersensitivity reactions to chloramphenicol and azidamphenicol, but not to thiamphenicol. These results were confirmed by lymphocyte transformation tests with peripheral blood mononuclear cells of the patients, showing a proliferative T-cell response to azidamphenicol and chloramphenicol. Moreover, lymphocytes from one patient secreted large amounts of interleukin-5, but not of interferon-gamma upon coculture with azidamphenicol.
  
  
  CONCLUSIONS
  Since lymphocyte reactivity was observed to chloramphenicol and azidamphenicol, but not to thiamphenicol, the epitope(s) recognized by the allergen-reactive T cells may be formed by the nitro-group of the benzene ring shared by chloramphenicol and azidamphenicol.
authors.affiliation: Department of Dermatology, University Hospitals, Rheinisch-Westfälische Technische Hochschule Aachen, Germany.
authors.forename: B
authors.initials: B
authors.lastname: Sachs
authors.forename: S
authors.initials: S
authors.lastname: Erdmann
authors.forename: T
authors.initials: T
authors.lastname: al Masaoudi
authors.forename: H F
authors.initials: HF
authors.lastname: Merk
mesh_terms: D000368:Aged; D000485:Allergens / Q000276:immunology; D000900:Anti-Bacterial Agents / Q000009:adverse effects / Q000276:immunology* / Q000494:pharmacology; D002701:Chloramphenicol / Q000009:adverse effects / Q000031:analogs & derivatives* / Q000276:immunology* / Q000494:pharmacology; D017449:Dermatitis, Allergic Contact / Q000276:immunology*; D004342:Drug Hypersensitivity / Q000276:immunology*; D000939:Epitopes / Q000276:immunology; D006801:Humans; D007371:Interferon-gamma / Q000096:biosynthesis; D015848:Interleukin-5 / Q000096:biosynthesis; D008213:Lymphocyte Activation; D008297:Male; D008875:Middle Aged; D010328:Patch Tests; D013601:T-Lymphocytes / Q000276:immunology; D013839:Thiamphenicol / Q000009:adverse effects / Q000276:immunology / Q000494:pharmacology
chemical_list: D000485:Allergens; D000900:Anti-Bacterial Agents; D000939:Epitopes; D015848:Interleukin-5; C004450:azidoamphenicol; D002701:Chloramphenicol; D007371:Interferon-gamma; D013839:Thiamphenicol