The Relationship between Proportion of Treg and Th17 Cells in Peripheral Blood in Sequence Pregnancy of Patients with Unexplained Recurrent Pregnancy Loss and Pregnancy Outcomes

Background: CD4⁺ regulatory T cells (Treg) suppress the reactivation of autoimmune disease and excess inflammation. However, T helper 17 cells (Th17), participate in the regulation of inflammatory reactions. This imbalance between Treg and Th17 cells influences immune homeostasis, which plays an important role in the maintenance of pregnancy.

Objective: To investigate Treg and Th17 cell numbers in the peripheral blood of patients with unexplained recurrent pregnancy loss (URPL), with an aim to evaluate their potential for predicting pregnancy outcomes.

Methods: Peripheral blood was collected from 60 URPL pregnant women and 56 healthy pregnant women, during their first trimester. These patients were recruited from the Second Affiliated Hospital of Soochow University from January 2014 to June 2015. The counts for Treg cells, Th17 cells, CD4⁺ T cells, and total lymphocytes in the peripheral blood were determined by flow cytometry, and the pregnancy outcomes were followed up. According to the different pregnancy outcomes, the patients with URPL were divided into two groups: URPL successful delivery group and URPL miscarriage again group. The ratios of Treg/CD4⁺ T cells, Treg/total lymphocytes, Th17/CD4⁺ T cells, Th17/total lymphocytes, and Treg/Th17 in the URPL successful delivery group, URPL miscarriage again group, and the normal successful delivery group were compared.

Results: The ratios of Treg/CD4+ T cells, Treg/total lymphocytes, and Treg/Th17 in the URPL miscarriage again group were significantly lower, whereas the ratios of Th17/CD4+ T cells and Th17/total lymphocytes were significantly higher (P <0.05) than those in the URPL successful delivery group and normal successful delivery group.

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Conclusion

Treg and Th17 cell counts in the peripheral blood of patients with URPL might be useful in predicting their pregnancy outcomes.