Regulatory T Cells and Pregnancy: Research Review

Whether caused by an autoimmune condition, infection, allergies, or another source, inflammation has been associated with reproductive challenges. During a healthy pregnancy, the body must be able to shift to a relatively anti-inflammatory state to maintain the pregnancy.

Regulatory T cells (Treg cells) are specialized immune cells that suppress inflammation and are essential for preventing the uterus from rejecting the embryo. Low Treg levels in the uterus are linked to infertility, recurrent miscarriage, and pregnancy complications. This test measures the patient’s circulating Treg cell levels, which can be used to help estimate recruitment of Treg cells to the uterus during pregnancy.

Physiology and published clinical data

Treg cells play a critical role in regulating tolerance to the semi-allogenic fetus presenting paternal alloantigens. These cells may prevent fetal rejection by the maternal immune system¹. Treg cells may promote fetal survival by inhibiting effector T cells and secreting anti-inflammatory factors such as IL-10 and TGF-β^2-3.

Treg cells are enriched in the fetal-maternal interface during early pregnancy⁴. They were shown to migrate from the peripheral blood to the decidua in pregnant subjects⁵. Thus, they might be recruited and expanded by the recognition to fetal antigens^1.