Expression of the phosphatidylinositol 3-kinase signaling pathway in peripheral blood T cells from patients with atopic dermatitis / 中华皮肤科杂志

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),supematant 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.