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Regulatory T Cells and Pregnancy: Research Review

A short overview of the role of regulatory T cells in pregnancy and controlling inflammation - and the science behind it.

March 31, 2022 Pregmune Team
regulatory t cells

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-β2-3.

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 antigens1.

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About Pregmune: We’re an innovative reproductive health technology company, built on a solid foundation of data gained from decades of experience and thousands of successful pregnancies. Our team of fertility specialists and scientists are using artificial intelligence to decipher the complexity of the immune system and help patients grow the families of their dreams.

Our first product, IRMA, provides patients and their doctors with a personalized report and evidence-based treatment plan that addresses immunological sources of unexplained infertility, recurrent pregnancy loss, and recurrent implantation failure.


1- Aluvihare VR, Kallikourdis M, Betz AG. Regulatory T cells mediate maternal tolerance to the fetus. Nat Immunol. 2004 Mar;5(3):266-71. doi: 10.1038/ni1037. Epub 2004 Feb 1. PMID: 14758358.

2- Robertson SA, Ingman WV, O’Leary S, Sharkey DJ, Tremellen KP. Transforming growth factor beta–a mediator of immune deviation in seminal plasma. J Reprod Immunol. 2002 Oct-Nov;57(1-2):109-28. doi: 10.1016/s0165-0378(02)00015-3. PMID: 12385837.

3- Yin Y, Han X, Shi Q, Zhao Y, He Y. Adoptive transfer of CD4+CD25+ regulatory T cells for prevention and treatment of spontaneous abortion. Eur J Obstet Gynecol Reprod Biol. 2012 Apr;161(2):177-81. doi: 10.1016/j.ejogrb.2011.12.023. Epub 2012 Jan 18. PMID: 22261465.

4- Mjösberg J, Berg G, Jenmalm MC, Ernerudh J. FOXP3+ regulatory T cells and T helper 1, T helper 2, and T helper 17 cells in human early pregnancy decidua. Biol Reprod. 2010 Apr;82(4):698-705. doi: 10.1095/biolreprod.109.081208. Epub 2009 Dec 16. PMID: 20018909.

5- Tilburgs T, Roelen DL, van der Mast BJ, de Groot-Swings GM, Kleijburg C, Scherjon SA, Claas FH. Evidence for a selective migration of fetus-specific CD4+CD25bright regulatory T cells from the peripheral blood to the decidua in human pregnancy. J Immunol. 2008 Apr 15;180(8):5737-45. doi: 10.4049/jimmunol.180.8.5737. PMID: 18390759.