Regulatory T helper cells in pregnancy and their roles in systemic versus local immune tolerance

Abstract

Problem: During pregnancy, the maternal immune system needs to adapt in order not to reject the semi-allogenic fetus.

Method: In this review, we describe and discuss the role of regulatory T (Treg) cells in fetal tolerance.

Results: Treg cells constitute a T helper lineage that is derived from thymus (natural Treg cells) or is induced in the periphery (induced Treg cells). Treg cells are enriched at the fetal-maternal interface, showing a suppressive phenotype. In contrast, Treg cells are not increased in the circulation of pregnant women, and the suppressive capacity is similar to that in non-pregnant women. However, aberrations in Treg frequencies and functions, both systemically and in the uterus, may be involved in the complications of pregnancy.

Conclusion: Treg cells seem to have distinguished roles locally versus systemically, based on their distribution and phenotype.