Intravenous Immunoglobulin G Modulates Peripheral Blood Th17 and Foxp3+ Regulatory T Cells in Pregnant Women with Recurrent Pregnancy Loss

Abstract

Th17 cells and Foxp3(+) regulatory T (Treg) cells have been proposed as new risk factors for recurrent pregnancy loss (RPL). Intravenous immunoglobulin G (IVIG) was reported to modulate various immune cells. In this study, we investigated the effect of IVIG on the levels of Th17 and Treg cells and pregnancy outcome in women with RPL. Thirty-seven pregnant women with RPL were enrolled in this study. All had cellular immune abnormality in preconceptional evaluation. Blood was drawn on the day of IVIG treatment and 1week later from the study subjects during early pregnancy. The proportions of IL-17(+) and Foxp3(+) T cells were analyzed using flow cytometry. Study population was divided into four groups (Q1-Q4) based on ascending order of the levels of Th17 and Foxp3(+) T cells. IVIG down-regulated Th17 cells in the highest quartile, Q4 (P=0.001), and up-regulated CD4(+) Foxp3(+) T cells in Q1 and Q2 (P=0.025 and 0.029, respectively). In addition, Th17/CD4(+) Foxp3(+) T cell ratio decreased in Q4 (P=0.040). We also found a positive trend between successful pregnancy outcome and CD8(+) IL-17(+) T cells before IVIG treatment (P=0.05). Intravenous immunoglobulin G treatment modulated imbalance of Th17 and Foxp3(+) Treg cells in pregnant RPL women with cellular immune abnormality.