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Expansion of CD4+HLA-G+ T Cell in Human Pregnancy is Impaired in Pre-eclampsia

Authors


Abstract

Problem

The role of CD4+HLA-G+ T cells in healthy pregnancy and pre-eclampsia is unclear.

Method of study

CD4+HLA-G+ T cells were analysed from peripheral blood and decidual samples from healthy pregnant and pre-eclamptic women. In vitro T-cell induction, trogocytosis and suppression assays were performed.

Results

In peripheral blood, CD4+HLA-G+ T cells were significantly higher in pregnant women (mean ± S.E.M.: 7.98 ± 1.10%), compared with non-pregnant controls (mean ± S.E.M.: 1.78 ± 0.30%) and pre-eclamptic women (mean ± S.E.M.: 3.69 ± 0.51%). The presence of CD4+HLA-G+ T cells is even more prominent in the decidua, suggestive of local induction and accumulation. Decidual CD14+DC-SIGN+ antigen-presenting cells (APCs) enhance the HLA-G expression of cocultured CD4+ naïve T cells in vitro. IL-10 augments expression of HLA-G, ILT4 and DC-SIGN in monocyte-derived DCs (MoDCs), endowing them with a phenotype analogous to decidual CD14+DC-SIGN+ APCs of healthy pregnancy. Furthermore, naïve T cells acquire HLA-G from these IL-10-treated MoDCs via the process of trogocytosis.

Conclusions

Our data indicate that in addition to Foxp3+ Treg cells, CD4+ T cells acquire HLA-G from decidual DCs and may play an important role in immune tolerance induction in pregnancy, a process which is impaired in pre-eclampsia.

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