title: Successful desensitization to fixed drug eruption: the presence of CD25+CD4+ T cells in the epidermis of fixed drug eruption lesions may be involved in the induction of desensitization.
abstract: BACKGROUND
  Fixed drug eruption (FDE) is a distinct type of drug-induced eruption, in which intraepidermal CD8+ T cells in the lesional skin are the final effector cells in the epidermal injury of FDE. Desensitization is a unique approach for the management of drug eruption, which has been reported to be effective in treating FDE. However, the mechanisms underlying desensitization to FDE are quite unknown.
  
  
  OBJECTIVE
  We reported a case of successful desensitization to allopurinol-induced FDE. To clarify the mechanisms underlying desensitization to FDE, we examined the phenotype of T cells in the epidermis of FDE lesions before and after desensitization using flow cytometry.
  
  
  RESULTS
  The overwhelming majority of intraepidermal T cells in the FDE lesion before desensitization consisted of CD8+ T cells, whereas a significant number of CD25+CD4+ T cells were present in the epidermis of FDE lesions after desensitization.
  
  
  CONCLUSIONS
  The presence of CD25+CD4+ T cells in the epidermis of FDE lesions may be involved in the induction of desensitization to FDE.
authors.affiliation: Department of Dermatology, Kyorin University School of Medicine, Tokyo, Japan.
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Teraki
authors.forename: Tetsuo
authors.initials: T
authors.lastname: Shiohara
mesh_terms: D000328:Adult; D000493:Allopurinol / Q000008:administration & dosage / Q000009:adverse effects*; D015704:CD4 Antigens / Q000096:biosynthesis*; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D003888:Desensitization, Immunologic / Q000379:methods; D003875:Drug Eruptions / Q000209:etiology / Q000276:immunology / Q000473:pathology / Q000628:therapy*; D005434:Flow Cytometry; D006801:Humans; D008297:Male
chemical_list: D015704:CD4 Antigens; D000493:Allopurinol