Pregnancy-associated diseases are characterized by the composition of the systemic regulatory T cell (Treg) pool with distinct subsets of Tregs

Dysregulations concerning the composition and function of regulatory T cells (T(regs)) are assumed to be involved in the pathophysiology of complicated pregnancies. We used six-colour flow cytometric analysis to demonstrate that the total CD4(+) CD127(low+/-) CD25(+) forkhead box protein 3 (FoxP3)(+) T(reg) cell pool contains four distinct T(reg) subsets: DR(high+) CD45RA(-), DR(low+) CD45RA(-), DR(-) CD45RA(-) T(regs) and naive DR(-) CD45RA(+) T(regs). During the normal course of pregnancy, the most prominent changes in the composition of the total T(reg) cell pool were observed between the 10th and 20th weeks of gestation, with a clear decrease in the percentage of DR(high+) CD45RA(-) and…