Pregnancy is maintained despite the fact that the foetation is a semi-foreign body to the mother.This system is called maternal and child immune tolerance, and it is known that regulatory T cells (Tregs), which have the function of suppressing immunity, play an important role in maintaining pregnancy.In mice, fetal antigen-specific Tregs are known to collect in the maternal uterus during pregnancy, but fetal antigen-specific Tregs have not yet been identified in humans.

　Therefore, the group now examined the expression of fetal antigen-specific Tregs in both early and late pregnancy in humans.As a result, it was clarified that the appearance rate of Treg having a common T cell receptor increases in the human pregnant uterus from the early stage to the late stage of pregnancy.That is, it was shown for the first time that fetal antigen-specific immune tolerance may be induced in late pregnancy.In addition, it was found that the number of Tregs in the uterus decreased in early pregnancy miscarriage with no abnormalities in the fetus, while the variation of Tregs in preeclampsia that developed in late pregnancy was different from that in normal pregnancy.

　This result has elucidated a part of the mechanism by which the foetation is maintained without being rejected, which contributes to the elucidation of the mechanism of recurrent miscarriage / preeclampsia and the development of new treatment / prevention methods. Be expected.　

　For these research results, Sayaka Tsuda, a graduate doctor, received the best presentation award at the "American Society for Reproductive Immunology Annual Meeting 2018, Shanghai" on June 6, 28.

Paper information:[Frontiers in Immunology] Clonally Expanded Decidual Effector Regulatory T Cells Increase in LateGestation of Normal Pregnancy, but Not in Preeclampsia, in Humans