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 CD4+CD25+CD127lo/− 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 CD4+CD25+CD127lo/− 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 CD4+CD25+CD127lo/− 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 mm2/wk over 10 weeks.
Conclusions: Intradermal steroid injections of weekly patch-test reactions resulted in hyposensitization of the allergic contact dermatitis reaction. CD4+CD25+CD127lo/− regulatory T cells showed a tendency to increase; however, further studies are needed to determine if this is significant.
From the Division of Dermatology, Department of Medicine, Royal University Hospital, University of Saskatchewan, Saskatoon, Saskatchewan, Canada.
Address reprint requests to Peter R. Hull, PhD, MB, BCh, FFDerm(SA), FRCPC, Division of Dermatology, Department of Medicine, Royal University Hospital, University of Saskatchewan, Saskatoon, Saskatchewan, Canada S7N 0W8. E-mail: firstname.lastname@example.org.
Research support was provided by the University of Saskatchewan, College of Medicine, Saskatoon Health Region.
The authors have no conflicts to declare.