title: Flow cytometric analysis of regulatory T cells during hyposensitization of acquired allergic contact dermatitis.
abstract: BACKGROUND
  We previously demonstrated that repeated intradermal steroid injections administered at weekly intervals into positive patch-test sites induce hyposensitization and desensitization.
  
  
  OBJECTIVE
  To examine changes in CD4CD25CD127lo/ regulatory T cells during the attenuation of the patch-test response.
  
  
  METHODS
  Ten patients with known allergic contact dermatitis were patch tested weekly for 10 weeks. The patch-test site was injected intradermally with 2 mg triamcinolone. At weeks 1 and 7, a biopsy was performed on the patch-test site in 6 patients, and flow cytometry was performed assessing CD4CD25CD127lo/ regulatory T cells. Secondary outcomes were clinical score, reaction size, erythema, and temperature. Statistical analysis included regression, correlation, and repeated-measures analysis of variance.
  
  
  RESULTS
  The percentage of CD4CD25CD127lo/ regulatory T cells, measured by flow cytometry, increased from week 1 to week 7 by an average of 19.2%. The average grade of patch-test reaction decreased from +++ (vesicular reaction) to ++ (palpable erythema). The mean drop in temperature following treatment was 0.28°C per week. The mean area decreased 8.6 mm/wk over 10 weeks.
  
  
  CONCLUSIONS
  Intradermal steroid injections of weekly patch-test reactions resulted in hyposensitization of the allergic contact dermatitis reaction. CD4CD25CD127lo/ regulatory T cells showed a tendency to increase; however, further studies are needed to determine if this is significant.
authors.affiliation: From the Division of Dermatology, Department of Medicine, Royal University Hospital, University of Saskatchewan, Saskatoon, Saskatchewan, Canada.
authors.forename: Kathleen
authors.initials: K
authors.lastname: Fraser
authors.forename: Mariam
authors.initials: M
authors.lastname: Abbas
authors.forename: Peter R
authors.initials: PR
authors.lastname: Hull
mesh_terms: D000893:Anti-Inflammatory Agents / Q000008:administration & dosage*; D001706:Biopsy; D018791:CD4 Lymphocyte Count; D017449:Dermatitis, Allergic Contact / Q000276:immunology* / Q000473:pathology / Q000628:therapy*; D003888:Desensitization, Immunologic; D005434:Flow Cytometry; D006801:Humans; D007271:Injections, Intradermal; D015552:Injections, Intralesional; D010328:Patch Tests; D012867:Skin / Q000473:pathology; D012881:Skin Temperature; D050378:T-Lymphocytes, Regulatory / Q000276:immunology*; D016896:Treatment Outcome; D014221:Triamcinolone / Q000008:administration & dosage*
chemical_list: D000893:Anti-Inflammatory Agents; D014221:Triamcinolone