Role of T helper 22 and 17 cells in pathogenesis of severe preeclampsia

Objective To investigate the role of T helper (Th) 22 and Th17 cells in the pathogenesis of severe preeclampsia. Methods Thirty women with severe preeclampsia who delivered in the Third Affiliated Hospital of Zhengzhou University from October 2014 to February 2016 were enrolled in the study. Thirty healthy pregnant women matched for age and gestational weeks were recruited as the control group. The frequencies of Th22 and Th17 cells in peripheral whole blood were determined by flow cytometry. The concentrations of interleukin (IL)-22 and IL-17A in plasma were detected by enzyme-linked immunosorbent assay. Independent two samples t-test, non-parametric test and Spearman correlation analysis were used for statistical analysis. Results The percentage of Th22 and Th17 cells in the severe preeclampsia group were significantly higher than those in the control group, respectively[Th22 cells: 0.59% (0.39%-1.13%) vs 0.40% (0.23%-0.57%), Z=2.530, P=0.010; Th17 cells: 3.24% (3.02%-3.97%) vs 1.87% (1.53%-2.64%), Z=5.046, P=0.000]. So were the plasma levels of IL-22 and IL-17A[IL-22: 285.72 (247.63-306.69) vs 233.85 (184.92-258.38) pg/ml, Z=4.341, P=0.001; IL-17A: 27.53 (23.84-32.78) vs 17.36 (15.58-19.13) pg/ml, Z=4.924, P=0.000]. There was a positive correlation between circulating Th22 and Th17 cells in the severe preeclampsia group (r=0.534, P=0.015), while no correlation was found in the control group (r=0.345, P=0.136). Positive correlation was found in plasma level of IL-22 with Th22 cells (r=0.600, P=0.005), but not with Th17 cells (r=0.398, P=0.082) in the severe preeclampsia group. Conclusions Increased Th22 cells and high IL-22 concentrations in the peripheral blood of severe preeclampsia patients may indicate a self-defense mechanism in the maternal body. Th22 cells and Th17 cells may interact with each other. Key words: Pre-eclampsia; T-lymphocytes, helper-inducer; Interleukins