Tregs in pregnancy with type 1 diabetes mellitus: pilot study

Pregnancy in women with type 1 diabetes mellitus has been associated with adverse outcomes due to persistent hyperglycemia and impaired maternal-fetal interactions. Regulatory T cells seem to exert a critical role in this process. Pregnancy can change the profile of Treg cells and affect the outcome of pregnancy; therefore, our purpose was to characterize the profile of regulatory T cells in the peripheral blood of pregnant and nonpregnant (controls) women with type 1 diabetes mellitus.

This prospective case-control study recruited 36 women with type 1 diabetes mellitus, 16 pregnant and 20 nonpregnant. Peripheral blood samples were collected in the three trimesters of pregnancy and only once in the control group. Flow cytometry was used to assess peripheral blood T subpopulations: CD3+, CD4+, CD8+, CD4+ Treg (CD4+CD25+CD127-FOXP3+), and CD8+ Treg (CD8+CD25+FOXP3). In addition, the expression of CD4+CD25high and CD4+CD25low was analyzed.

Compared to controls, the pregnant women (regardless of the trimester) presented a lower percentage of TCD4+CD25high, TCD4+CD25low, and CD8 Treg (CD8+CD25+FOXP3+). Moreover, a higher percentage of total TCD8+ lymphocytes was observed in pregnant women than in controls.

This study reported changes in the circulating Treg cell profile that seem to be associated with pregnancy in type 1 diabetes mellitus patients and pregnancy outcomes.