Intravenous immunoglobulin G modulates peripheral blood Th17 and Foxp3(+) regulatory T cells in pregnant women with recurrent pregnancy loss.

PROBLEM: 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. METHOD OF STUDY: 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 1 week later from the study subjects during early pregnancy. The proportions of IL-17(+) and Foxp3(+) T cells were analyzed using flow cytometry. RESULTS: 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). CONCLUSION: Intravenous immunoglobulin G treatment modulated imbalance of Th17 and Foxp3(+) Treg cells in pregnant RPL women with cellular immune abnormality.

Determination of clinical cellular immune markers in women with recurrent pregnancy loss.

PROBLEM: Dysregulated natural killer (NK) immunity and T-cell immunity are associated with recurrent pregnancy loss (RPL). We aim to define clinically relevant NK and T-cell parameters for RPL and determine their cutoff values. METHODS OF STUDY: Ninety-five women with RPL (>3) including 42 idiopathic and 53 known-etiology RPL, and 29 age-matched fertile controls were enrolled. Peripheral blood immunophenotype, NK cell cytotoxicity (NKC), and T-helper (Th) 1 and Th2 cytokine producing cell ratios (Th1/Th2) were measured using flowcytometry. The cutoff values were determined using Youden's J with likelihood ratio (LR) >2. RESULTS: Natural killer cell percentage and NKC, TNF-α(+) Th1 cells, and TNF-α/IL-10 producing Th1/Th2 cell ratio were significantly higher in idiopathic RPL than controls. By the area under the curve (AUC) analysis, NK cell percentage (AUC = 0.691), NKC (AUC = 0.649), TNF-α(+) Th1 cells (AUC = 0.681) and Th1/Th2 cell ratio (AUC = 0.660) were highly specific for RPL. The cutoff values for NK cell percentage, NKC (E:T cell ratio 25:1), and TNF-α/IL-10 producing Th1/Th2 cell ratio are 16.1, 23.8, and 36.2%, respectively. Seventy-six percent of idiopathic RPL showed at least one of more immune abnormalities by these criteria. CONCLUSION: Differences in NK cell percentages, NKC and Th1/Th2 cell ratio differentiated RPL from fertile controls.

Th17 and regulatory T cells in women with recurrent pregnancy loss.

The immune system of pregnant women is tightly controlled to defend against microbial infections and at the same time, to accept an embryo or the fetus, which are expressing semi-allogenic paternal antigens. Furthermore, inflammation-like processes are crucial for tissue growth, remodeling, and differentiation of the decidua during pregnancy. Dysregulation of elaborate immune control may lead reproductive failure, such as implantation failure, recurrent pregnancy loss (RPL), preterm birth, intrauterine fetal growth restriction, and preeclampsia. Until recent years, a balance between Th1 and Th2 cells was believed to be the key immune regulatory mechanism of T-cell immunology especially during pregnancy. Since the identification of regulatory T cells was made, the mechanism of immune regulation has become a major issue in immunologic research. Also, the recent identification of Th17 cells has drawn our attention to a new immune effector. The balance between Th17 and regulatory T cells may explain more about the pathophysiology of reproductive failure. This review will discuss relevant human literature on regulatory T and Th17 cells in normal reproductive physiology and in women with RPL and infertility.

Foxp3(high) and Foxp3(low) Treg cells differentially correlate with T helper 1 and natural killer cells in peripheral blood.

Regulatory T (Treg) cells interact with B, natural killer (NK), and dendritic cells in addition to other T cells. In this study, we aimed at determining whether Foxp3(+) T cells and subpopulations have any correlation with other lymphocyte subsets and their functions in a systemic immune environment. Peripheral blood was drawn from 22 nonpregnant healthy women. T, B, and NK cell subpopulations were measured by immunophenotype analysis. Intracellular Foxp3, cytokine expression (tumor necrosis factor-α [TNF-α], interferon-γ [IFN-γ], and interleukin-10 [IL]-10), and NK-cell cytotoxicity were analyzed by flow cytometric analysis. Correlations between Foxp3(+) T cells and other immune variables were analyzed under control of age and menstrual phases. Foxp3(+), Foxp3(low), and CD4(+)Foxp3(+) cells significantly correlated with CD4(+)CD25(+), CD4(+)CD25(dim), and CD4(+)CD25(bright) cells. Foxp3(+), Foxp3(low), and CD4(+)Foxp3(+) cells positively correlated with CD3(+) and CD3(+)CD4(+) T cells, but negatively correlated with CD3(-)CD56(+) and CD3(-)CD56(dim) NK cells. CD4(+)Foxp3(high) Treg cells were positively correlated with CD3(+)CD4(+)TNF-α(+) (p = 0.014) and negatively correlated with CD3(+)CD8(+)IL-10(+) T cells (p = 0.001). The ratio of type 1/2 cytokine-producing CD3(+)CD8(+) cells demonstrated a positive correlation with CD4(+)Foxp3(high) cells (p ≤ 0.01). CD8(+)Foxp3(+) cells were positively correlated with CD3(+)CD4(+)IL-10(+) cells (p = 0.007) and negatively correlated with CD3(+)CD8(+)TNF-α(+) cells (p = 0.008). In conclusion, each Foxp3(+) Treg cell subpopulation has unique immune interaction, which controls particular subsets of lymphocytes.

Role of endometrial immune cells in implantation.

Implantation of an embryo occurs during the mid-secretory phase of the menstrual cycle, known as the "implantation window." During this implantation period, there are significant morphologic and functional changes in the endometrium, which is followed by decidualization. Many immune cells, such as dendritic and natural killer (NK) cells, increase in number in this period and early pregnancy. Recent works have revealed that antigen-presenting cells (APCs) and NK cells are involved in vascular remodeling of spiral arteries in the decidua and lack of APCs leads to failure of pregnancy. Paternal and fetal antigens may play a role in the induction of immune tolerance during pregnancy. A balance between effectors (i.e., innate immunity and helper T [Th] 1 and Th17 immunity) and regulators (Th2 cells, regulatory T cells, etc.) is essential for establishment and maintenance of pregnancy. The highly complicated endocrine-immune network works in decidualization of the endometrium and at the fetomaternal interface. We will discuss the role of immune cells in the implantation period and during early pregnancy.

Fluctuation of peripheral blood T, B, and NK cells during a menstrual cycle of normal healthy women.

Cyclical hormonal changes during an ovarian cycle may affect immune responses, which is crucial for the embryonic implantation. We aim to investigate whether the levels and activity of T, B, and NK cells change during a menstrual cycle. Twenty-two normally cycling women were enrolled and peripheral blood was drawn serially during a menstrual cycle. Intracellular cytokine expression of CD3(+)CD4(+) and CD3(+)CD8(+) cells, and Th1/Th2 cytokine-producing T cell ratios were determined using flow cytometric analysis. NK cell cytotoxicity was measured by flow cytometric analysis at E:T ratios of 50:1, 25:1, and 12.5:1 and also using LU at 20%. Proportions (percentage) of CD3(+) (p = 0.046) and CD3(+)CD4(+) (p = 0.002) T cells were increased in the follicular phase compared with the luteal phase. The levels of CD3(-)CD56(+) (p = 0.010) and CD3(-)CD56(dim) (p = 0.012) NK cells and NK cytotoxicity at E:T ratio of 50:1, 25:1, and 12.5:1 and LU at 20% were significantly increased in the luteal phase compared with the follicular phase. Even though IL-10-producing CD3(+)CD4(+) T cells were significantly lower in the midluteal phase as compared with the early follicular phase, proportions of CD19(+) B cells, CD3(+)CD56(+) NKT cells, Th1 cytokine-producing T cell subsets, and ratios of Th1/Th2 cytokine-producing T cells were not significantly changed during a menstrual cycle. We conclude that peripheral blood NK and T cell levels as well as NK cytotoxicity are changed during a menstrual cycle. Neuroendocrine regulation on immune responses is suggested during an ovarian cycle, which may be critical for embryonic implantation and pregnancy.