Abstract: Wei Ming*, Tu Ling, Liang Yinghong, Liu Jia, Gong Yanjie, Zhang Junhua, Zhang Yihua. *Department of Clinical Laboratory, Fifth Affiliated Hospital of Zhengzhou University, Zhengzhou 450052, China Corresponding author: Wei Ming, Email: gushiweiming@126.com 【Abstract】 Objective To estimate the activity of the phosphatidylinositol3-kinase （PI3K） signaling pathway in peripheral blood T cells from patients with atopic dermatitis （AD）, and to investigate its clinical significance. Methods T cells were isolated by using the Rosettsep T cell purification kit from the peripheral blood of 38 patients with AD and 38 healthy human controls, and classified into several groups to be treated with anti-CD3 monoclonal antibody, anti-CD28 monoclonal antibody, and LY294002 （an inhibitor of PI3K） respectively. The activity of PI3K signaling pathway in T cells was estimated by immunoprecipitation and enzyme-linked immunosorbent assay （ELISA）. Western blot was performed to measure the expressions of total Akt and phosphorylated Akt in T cells, methyl thiazolyl tetrazolium （MTT） assay to examine the proliferation of T cells, and ELISA to determine the levels of interleukin 6 （IL-6） and IL-10. Results The activity of PI3K and Akt was significantly higher in freshly isolated patient-derived T cells than in control-derived T cells （both P < 0.05）. However, the difference in the activity of PI3K and Akt between patient-derived and control-derived T cells disappeared （both P > 0.05） after 24-hour in vitro culture. The activity of PI3K and Akt in control-derived T cells was significantly increased after 24-hour incubation with sera from the patients with AD （both P < 0.05）. In addition, compared with patient-derived T cells treated with patients′ sera or anti-CD3/CD28 monoclonal antibody alone, those treated with the combination of LY294002 and patients′ sera or anti-CD3/CD28 monoclonal antibody showed a significant decrease in the proliferative activity （63% ± 11% vs. 123% ± 25%, 125% ± 22% vs. 195% ± 28%, both P < 0.05）, supernatant levels of IL-6 （（168 ± 33） vs. （265 ± 46） ng/L, （431 ± 64） vs. （823 ± 128） ng/L, both P < 0.05） and IL-10 （（56 ± 14） vs. （98 ± 25） ng/L, （120 ± 21） vs. （213 ± 35） ng/L, both P < 0.05）. Eczema area and severity index （EASI） was unassociated with the activity of PI3K or Akt in fresh T cells from patients with AD （both P > 0.05）. Conclusions The PI3K signaling pathway is abnormally activated in peripheral blood T cells from patients with AD, which is associated with the proliferation of, as well as secretion of cytokines by, T cells, suggesting that there exist serum factors activating this pathway in peripheral blood of patients with AD.

Key words: Dermatitis, atopic, T-Lymphocytes, Signal transduction