Alteration of Th17 and Foxp3+ regulatory T cells in patients with unexplained recurrent spontaneous abortion before and after the therapy of hCG combined with immunoglobulin

Abstract

We conducted this study to investigate the effects of the combination therapy of human chorionic gonadotropin (hCG) plus immunoglobulin (IG) on the levels of T helper 17 (Th17) cells and Foxp3⁺ regulatory T cells (Treg) in patients with unexplained recurrent spontaneous abortion (URSA). Twenty pregnant women with URSA underwent combination therapy of hCG plus IG. Flow cytometry was performed to measure the proportions of Th17 and Treg cells before and after treatment. RT-PCR and ELISA were applied to detect the concentrations of interleukin (IL)-17, IL-6, IL-10, and transforming growth factor (TGF)-β₁ in the peripheral blood. The therapy of hCG combined with IG may induce a decrease in the Th17/Treg ratio and the Treg bias, which may be beneficial for the maintenance of pregnancy. The levels of Th17 cells and related cytokines IL-17 and IL-6 decreased after the treatment (P<0.05). At the same time, levels of Treg cells and the related cytokines IL-10 and TGF-β₁ increased (P<0.05). The Th17/Treg ratio decreased significantly after treatment. In conclusion, the occurrence of URSA may be associated with the Th17/Treg balance disorder, and correcting the disorder may be one of the mechanisms behind the efficacy of combination therapy for URSA.

Keywords: Th17 cells; human chorionic gonadotropin; immunoglobulin; regulatory T cells; unexplained recurrent spontaneous abortion.

Figure 1.

The percentage of T helper 17 (Th17) and regulatory T (Treg) cells in peripheral blood mononuclear cells (PBMCs) and the Th17/Treg ratio varies in patients with a successful pregnancy after immunotherapy. The percentage of Th17 and Treg cells in PBMCs were detected by flow cytometry in patients with unexplained recurrent spontaneous abortion (URSA) before and after therapy. Representative CD3⁺CD8⁺IL-17A⁺ flow cytometry plots from patients with URSA are shown (A) before and (B) after therapy. Representative CD4⁺CD25⁺Foxp3⁺ flow cytometry plots from patients with URSA are shown (C) before and (D) after therapy. (E) The percentage of Th17 cells in PBMCs significantly decreased after therapy. The percentage of Treg cells in PBMCs significantly increased after therapy (*P<0.01, paired t-test). Bar represents the Th17 and Treg cell frequency and the means ± SEM are indicated. (F) The Th17/Treg ratio in PBMCs significantly decreased after therapy (P<0.01, paired t-test). Bar represents the frequency and the means ± SEM are indicated.

Figure 2.

(A) RT-PCR and (B) enzyme-linked immunosorbent assay (ELISA) results of interleukin (IL)-17, IL-6, IL-10 and transforming growth factor-β₁ (TGF-β₁) in the peripheral blood of unexplained recurrent spontaneous abortion (URSA) patients before and after therapy. The concentrations of Th17-type cytokines IL-17 and IL-6 were significantly decreased in the serum of patients with URSA after therapy (*P<0.01, paired t-test). Treg-type cytokines such as IL-10 and TGF-β1 were significantly increased after therapy (*P<0.01, paired t-test). Values are expressed as the mean ± SEM.