Treg Cells Are Negatively Correlated with Increased Memory B Cells in Pre‐eclampsia While Maintaining Suppressive Function on Autologous B‐Cell Proliferation

Abstract

The objective of this study was to determine the simultaneous changes and the correlation between circulating regulatory T (Tregs) and B-cell subsets in normal pregnancy (NP) and pre-eclampsia (PE). Meanwhile, the regulatory function of Tregs on B-cell proliferation was evaluated in vitro. A total of 32 PE and 40 NP women matched for age, gestational age, and parity were included. Using flow cytometry, the percentages of peripheral blood Tregs and B-cell subsets were determined. Moreover, the regulatory function of Tregs on autologous B-cell proliferation in PE and NP was investigated in vitro by flow cytometry and analyzed by modfit software. The proportions (%) of CD4(+) Foxp3(+) (P<0.001) and CD4(+) CD25(+) Foxp3(+) (P<0.01) cells within total CD4(+) T cells were significantly decreased in PE as compared to those of NP. However, no difference was found in CD4(+) CD25(+) cells in CD4(+) T cell population. CD19(+) CD27(+) (P<0.05) and CD19(+) CD27(+) IgD(+) (P<0.01) B cells within CD19(+) B cells (%) in PE were higher than those of NP. Negative correlations between the percentage of CD4(+) CD25(+) Foxp3(+) in CD4(+) T cells and that of CD19(+) CD27(+) (r=-0.384, P<0.05) and CD19(+) CD27(+) IgD(+) (r=-0.402, P<0.05) in CD19(+) B cells were present in PE but not in NP. Furthermore, the in vitro study demonstrated a significant increase in B-cell proliferation in PE as compared to NP. Tregs in PE were able to suppress the proliferation and precursor frequency of autologous B cells (P<0.05 each). The study indicates that a negative correlation between Tregs and memory B cells is present in women with PE, characterized by a systemic decrease in Tregs and an increase in memory B cells. Although the quantitative deficit of Tregs is present in PE, the Tregs still have a suppressive role in autologous B-cell proliferation.