Treg Cells Are Negatively Correlated with Increased Memory B Cells in Pre-eclampsia While Maintaining Suppressive Function on Autologous B-Cell Proliferation
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.
Method of study
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.