Abstract: MA Lei *, XUE Hai-bo, GUAN Xiu-hao, YUN Bei-lei, WANG Juan, ZHANG Jun-hua, AN Rong-zhen, ZHANG Yu-jie. *Department of Dermatology, Affiliated Hospital of Binzhou Medical University, Binzhou 256603, Shandong, China Corresponding author: XUE Hai-bo, Email: xuehaibo@sina.com 【Abstract】 Objective To determine the proportion of peripheral blood regulatory T （Treg） cells as well as mRNA expressions of miR-31 and Foxp3 in peripheral blood and skin lesions from patients with atopic dermatitis （AD）, and to assess their association. Methods Peripheral blood samples were obtained from 37 patients with AD and 33 age- and sex-matched healthy controls, and biopsy samples from the lesional and perilesional skin of 5 patients with AD as well as from the normal skin of 5 healthy controls. Flow cytometry was performed to determine the percentage of Treg cells （CD4+CD25+Foxp3+ T cells） in peripheral blood, and fluorescence-based real time quantitative reverse transcription （RT）-PCR to quantify the mRNA expressions of miR-31 and Foxp3 （a Treg cell-specific transcription factor） in peripheral blood and skin samples. Independent samples t test was carried out to compare the percentage of Treg cells as well as the mRNA expressions of miR-31 and Foxp3 in peripheral blood between the patients and controls, one-way analysis of variance to compare the mRNA expressions of miR-31 and Foxp3 in biopsy samples between the patients and controls, and Pearson correlation analysis to evaluate the relationship between miR-31 mRNA expression level, SCORing Atopic Dermatitis （SCORAD） score, Treg cell percentage, and Foxp3 mRNA expression level. Results The patients with AD showed decreased Treg cell percentage （2.12% ± 0.60% vs. 4.99% ± 1.27%，P < 0.01） and Foxp3 mRNA expression level（0.78 ± 0.17 vs. 1.87 ± 0.71, P < 0.01）, but increased miR-31 mRNA expression level（6.01 ± 1.76 vs. 1.62 ± 0.51, P < 0.01）in peripheral blood compared with the healthy controls. The expression level of miR-31 mRNA sequentially decreased（F = 54.501, P < 0.01）, but the expression of Foxp3 mRNA sequentially increased （F = 37.837, P < 0.01） from lesional skin, perilesional skin to normal skin tissues. The miR-31 mRNA expression level was positively correlated with SCORAD score （r = 0.417, P = 0.010）, but negatively correlated with Treg cell percentage （r = －0.404, P = 0.013） and Foxp3 mRNA level （r = －0.409, P = 0.012） in peripheral blood of patients with AD. There was a negative correlation between the mRNA expression level of miR-31 and Foxp3 in lesional and peri-lesional skin tissues of the patients （r = －0.392, P = 0.032）. Conclusion The upregulated miR-31 expression and downregulated Foxp3 expression may be associated with the development of AD. 【Key words】 Dermatitis, atopic; miR-31; T-lymphocytes, regulatory; Foxp3

Key words: miR-31, Foxp3