Proportion of CD56+3+ T cells in decidual and peripheral lymphocytes of normal pregnancy and spontaneous abortion with and without history of recurrent abortion

Phenotypic characterization of NKT-like cells and evaluation of specifically related cytokines for the prediction of unexplained recurrent miscarriage

Problem

Immune system dysregulation is a major cause of unexplained recurrent miscarriage (URM). Women with URM need screening for their pregnancy microenvironment and immune regulators, to prevent spontaneous abortion.

Method of study

In this study we evaluated NKT-like cell subsets in peripheral venous blood of women with URM using flow cytometry. The expression levels of specifically related Th1 cytokines (IFN-γ and IL-2), Th2 cytokine (IL-4), and Th17 cytokines (IL-17), were measured using enzyme-linked immunosorbent assay.

Results

The percentage of CD16+CD56+NKT-like (Double Positive NKT-like; DPNKT-like) cell subset, and the levels of IL-2 and IFN-γ were significantly elevated in blood of non-pregnant and pregnant patients with URM compared with the healthy control groups, and these parameters were significantly increased after pregnancy in the same patients with URM. Based on the prevalence of the candidate immunological factors in patients with URM, the prognostic significance of the NKT-like cell subsets, IFN-γ and IL-2 profiles were evaluated as potential predictors of URM. A cut-off point of 2.55% for DPNKT-like cell subset in the blood and cut-off values of 39.5 and 20.5 pg/ml for the levels of IFN-γ and IL-2, respectively could be used for the prediction of the risk of spontaneous abortion. To the best of our knowledge, this is the first study that described the prognostic significance of the aforementioned immunological parameters before and after pregnancy, and highlighted the correlation of NKT-like cells and the candidate Th1 cytokines with pregnancy loss in women with URM.

Conclusions

DPNKT-like cells, IFN-γ and IL-2 patient profiles could be used as markers to predict the risk of miscarriage in patients with URM.

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Disturbance in the immune system's regulators is an essential factor for recurrent miscarriage.

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There is an urgent need for women who have suffered pregnancy loss to identify specific immune regulators that underline recurrent miscarriage, to prevent and control miscarriage.

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CD16+CD56+NKT-like cells, Interferon-γ and Interleukin-2 patient profile could be utilized as biomarkers to predict risk of miscarriage in women who have suffered spontaneous miscarriage.

The low cytotoxic activity of peripheral blood NK cells may relate to unexplained recurrent miscarriage

PROBLEM

Unexplained recurrent miscarriage (uRM) is defined as two or more spontaneous abortions prior to 20 weeks of gestation with unknown etiology. Peripheral blood natural killer (pNK) cells contact with the villus and exert important role in normal pregnancy. However, it is still controversial about the association between pNK cytotoxicity and uRM, and the underlying mechanism remains unknown so far.

METHOD OF STUDY

In this study, we aim to compare the percentage, immunophenotype, and function of pNK cells between patients with uRM and fertile controls. The peripheral blood was collected from 49 patients with uRM and 11 fertile women in their middle luteal phase of the menstrual cycle. pNK cells were co-cultured with K562 cells at different cell ratios to measure the cytotoxicity. The percentage of CD3^- CD56⁺ , CD3^- CD56^bright , and CD3^- CD56^dim pNK was analyzed by flow cytometry and quantified to evaluate the expression of cytotoxic granules (granzyme B, granulysin, and perforin), and the cell surface receptors related to pNK cell cytotoxicity (NKG2D, NKp30, NKp46, CD158a, and CD158b) were also detected.

RESULTS

The general linear model analysis showed that pNK cell cytotoxicity in patients with uRM was significantly lower than that in fertile controls. In addition, the ratios of NKG2D/CD158a, NKp30/CD158a, and NKp46/CD158a in CD3^- CD56^bright pNK subsets were significantly lower in uRM group than that in fertile control. The logistical regression analysis showed that the reduced NKp30/CD158a, NKp46/CD158a ratios in CD3^- CD56^bright pNK subsets were significantly associated with uRM.

CONCLUSION

Our results suggested that a low pNK cytotoxicity, which is mediated by inhibitory signals, might be associated with uRM.

Functional significance of lymphocytes in pregnancy and lymphocyte immunotherapy in infertility: A comprehensive review and update

During pregnancy, the fetal-maternal interface underlies several dynamic alterations to permit the fetus to be cultivated and developed in the uterus, in spite of being identifies by the maternal immune system. A large variety of decidual leukocyte populations, including natural killer cells, NKT cells, innate lymphoid cells, dendritic cells, B cells, T cells, subpopulations of helper T cells play a vital role in controlling the trophoblast invasion, angiogenesis as well as vascular remodeling. In contrast, several regulatory immunosuppressive mechanisms, including regulatory T cells, regulatory B cells, several cytokines and mediators are involved in maintain the homeostasis of immune system in the fetal-maternal interface. Nonetheless, aberrant alterations in the balance of immune inflammatory or immunosuppressive arms have been associated with various pregnancy losses and infertilities. As a result, numerous strategies have been developed to revers dysregulated balance of immune players to increase the chance of successful pregnancy. Lymphocyte immunotherapy has been developed through utilization of peripheral white blood cells of the husband or others and administered into the mother to confer an immune tolerance for embryo's antigens. However, the results have not always been promising, implying to further investigations to improve the approach. This review attempts to clarify the involvement of lymphocytes in contributing to the pregnancy outcome and the potential of lymphocyte immunotherapy in treatment of infertilities with dysregulated immune system basis.

The number and cytotoxicity and the expression of cytotoxicity-related molecules in peripheral natural killer (NK) cells do not predict the repeated implantation failure (RIF) for the in vitro fertilization patients

Natural killer (NK) cells are thought to play a key role in the successful establishment of a pregnancy by facilitating immunological adaptation of the semi-allogeneic developing embryo. The aim of this study was to explore the cell number, immunophenotypic characteristics, and activities of peripheral blood NK cells in women with repeated implantation failure (RIF). Peripheral blood was obtained from 27 women with RIF and 11 healthy, fertile controls during the middle luteal phase of the menstrual cycle. CD3^- CD56⁺ NK cells were quantified and analyzed by flow cytometry for the expression of cytolytic molecules (granzyme B, granulysin, and perforin) as well as cell surface receptors responsible for NK cell activation or inhibition (NKG2D, NKp30, NKp46, CD158a, CD158b). NK cytotoxicity was measured at three effector-to-target cell ratios. Women with RIF and fertile controls did not differ significantly in the percentage of circulating CD3⁻CD56⁺ NK cells, or in the proportions of these cells that expressed granzyme B, granulysin, or perforin. The two groups also did not differ significantly in the proportions of NK cells expressing the receptors NKG2D, NKp30, NKp46, CD158a or CD158b. General linear model analysis showed that NK cytotoxicity increased with effector-to-target cell ratio. However, NK cytotoxicity did not differ significantly between patients with RIF and fertile controls. These results suggest that RIF is not associated with significant alterations in the number or function of peripheral blood NK cells.

Diminished Frequency of Menstrual and Peripheral Blood NKT-Like Cells in Patients With Unexplained Recurrent Spontaneous Abortion and Infertile Women

Systemic monitoring of immune system may not precisely outline the local immune status in the uterus. This survey is a continuation of our previous studies on potential usefulness of menstrual blood (MB) immunophenotyping as a tool for investigation of immunological disturbances in pregnancy-related disorders. Peripheral blood (PB) and MB from healthy fertile (n = 15), unexplained recurrent spontaneous abortion (URSA; n = 15), and unexplained infertile women (n = 8) were collected simultaneously in the second day of their menstrual cycle and frequency of natural killer T (NKT)-like cell subpopulations were assessed by flow cytometry. Menstrual blood of all experimental groups contained higher percentage of TCRαβ⁺, CD45RO⁺, and CD16^- NKT-like cells compared to corresponding PB. Frequency of MB NKT-like cells in unexplained infertile participants was lower than fertile and URSA groups. Compared to normal participants, patients with URSA had lower frequency of PB TCRαβ⁺ and higher CD16⁺, while in infertile woman frequencies of PB CD45RO⁺, CD45RO^-, CD16^-, IL17⁺, and MB CD45RO⁺ NKT-like cells were lower. Although, PB and MB seemingly have the same histological nature, our results showed that MB contained different composition of NKT-like subsets with different cytokine profiles and could be viewed as one potential biological sample for evaluation of patients with infertility and URSA.

The Predominant Th1 Cytokine Profile in Maternal Plasma of Preeclamptic Women Is Not Reflected in the Choriodecidual and Fetal Compartments

OBJECTIVE

Human pregnancy disorders such as preeclampsia are thought to involve variations in cytokine levels. It has been proposed that, in preeclamptic women, a balance favoring the Th1-type over the Th2-type cytokine profile determines local or systemic immunologic responses to pregnancy and that this may cause defective placental implantation and placental ischemia, which activate systemic endothelial cells. The purpose of this study was to determine whether cytokine expression differs in the maternal, choriodecidual, and fetal compartments, and between women with or without preeclampsia.

METHODS

Plasma concentrations of interferon gamma (IFNgamma), interleukin (IL)-2, IL-4, and IL-10 were measured by enzyme-linked immunosorbent assay (ELISA) in samples obtained from maternal peripheral blood (MPB), choriodecidual (CD), and fetal cord (FC) blood compartments of 17 women with preeclampsia and in 15 normotensive women. Intracellular concentrations of IFNgamma and IL-2 in T lymphocytes were assessed by flow cytometry.

RESULTS

Plasma IFNgamma concentrations in both MPB and CD compartments were significantly higher in preeclamptic than in normotensive women. Maternal plasma IL-4 concentration was significantly lower in preeclamptic than in normotensive women. Intracellular IFNgamma and IL-2 concentrations did not differ significantly between preeclamptic and normotensive women.

CONCLUSIONS

The dominant Th1-type over Th2-type cytokine profile is evident in MPB, but not in the CD and FC blood compartments. This might reflect the complex cytokine networks in the fetal-placental interface and might involve trophoblasts or decidual and endothelial cells, which could account for the increased plasma IFNgamma concentration and T-helper cell number.

Increase of peripheral blood TCD8+ cells in women with recurrent miscarriage

Recurrent miscarriage (RM) is one of the most prevalent reproductive problems faced by couples that may affect as many as 2% of women in reproductive age. The causes of its abnormality have attracted the attention of many researchers. We aim to determine the different T-cell subsets in women with RM and normal control. In this prospective case-control study, peripheral blood was taken from women with RM (n = 25) and normal women (n = 17), during the mid-luteal phase. The percentage of CD3, CD3(+)CD4(+), CD3(+)CD8(+) markers and also CD4/CD8 ratio was detected in the patients and control group by flow cytometry. The proportion of TCD8(+) was significantly higher in RM women compared with the control group (p < 0.05). However, there was no statistical difference in percentage of total TCD3(+) and TCD4(+) cells between the RM and control women. Also, the CD4/CD8 ratio was lower in the RM women compared with the control women. These observations support the concept that increase of TCD8(+) lymphocytes could be involved in the aetiology of RM.

Quantitative and functional changes in peripheral natural killer cells in women with reproductive failure after artificial insemination with donor sperm

Considerable evidence indicates that quantitative and/or functional abnormalities of natural killer (NK) cells are associated with reproductive failure. The objective of this study was to determine if peripheral NK percentage and activity are altered in women with reproductive failure after artificial insemination by donor (AID), and which parameters can best discriminate women with AID failure and normal controls. A case-control study of 20 fertile controls, 25 patients undergoing more than four treatment cycles without success (Group I), 25 experiencing biochemical pregnancy loss (Group II), and 25 undergoing embryo growth arrest or miscarriage (Group III) was performed. The peripheral NK percentage and cytotoxicity was evaluated by flow cytometry. Our results showed that a significantly increased percentage of NK cell cytotoxicity (NKCC) was detected in all study groups compared with the controls. The percentage of CD56(+) NK cells was elevated in Groups II and III compared with the controls. The percentage of CD56(+)CD16(+) NK cells in the study groups was higher than that in the controls. By using receiver operating characteristic curve and logistic regression analysis, we found that NKCC combined with CD56(+)CD16(+) NK percentage had good predictive power. The overall predicted percentage correct was 0.89. These results suggest that enhanced NKCC and an elevated cytotoxic NK percentage may be associated with AID failure and can be biomarkers for predicting AID-induced failure.

How valuable is measurement of peripheral blood natural killer cells at the time of abortion?

PROBLEM

Increased peripheral blood natural killer (NK) cells are associated to immune-mediated abortion, but their diagnostic value when measured at the time of miscarriage is unknown.

METHOD OF STUDY

In women with therapeutic (A = 79) or elective (C = 34) pregnancy termination, the NK-cell percentage was measured before and 5 days after curettage. Additionally, immune-mediated lesions (scored 0-3) and CD56(+) and CD16(+) decidual NKs (scored 1-3) were detected on the abortion material.

RESULTS

Aborters differed from controls in histological scores (P = 0.000) and in NK percentage (>12%) only in the measurement 5 days after the operation (P = 0.038). In comparison to histological lesions, NK measurement was found to have sensitivity 70%, specificity 73.68%, positive prognostic value 89.39% and negative prognostic value 43.75%.

CONCLUSION

An Increased NK-cell percentage 5 days after the pregnancy termination could be a marker of immune aetiology of miscarriage, as the probability of an aborter with NK >12% to have an immune-mediated abortion is almost 90%.

Simple enumerations of peripheral blood natural killer (CD56+ NK) cells, B cells and T cells have no predictive value in IVF treatment outcome

BACKGROUND

To evaluate the association between the absolute counts of the peripheral natural killer (NK) cells (including total CD56(+) NK cells, CD56(dim) NK cells and CD56(bright) NK cells), B cells and T cells on the implantation rate and miscarriage rate after IVF treatment.

METHODS

This was a prospective observation study. A total of 138 patients who underwent IVF treatment from December 2002 to July 2003 were recruited to the study. Blood samples were obtained on the day of vaginal oocyte retrieval prior to the procedure. The absolute counts of lymphocytes, NK cells, B cells and T cells were identified by flow cytometry. These absolute counts and their relationships to IVF treatment outcome and miscarriage rate were analysed.

RESULTS

There were no significant differences with regard the mean values of absolute lymphocyte count, T cell count, B cell count and NK cell count (including total CD56(+) NK, CD56(dim) NK and CD56(bright) NK cells) between the pregnant and non-pregnant groups and also between the ongoing pregnancy and miscarriage groups. The cause of infertility, duration of infertility, basal FSH levels, number of previous failed IVF treatments, number of previous miscarriages and stimulation characteristics were not significantly different between the pregnant and non-pregnant groups. Previous studies have suggested that women with a history of recurrent miscarriage and those with infertility accompanied by recurrent failed IVF treatments are associated with a peripheral blood NK cell percentage >12%, therefore further analysis of peripheral CD56(+) NK cell levels <12% (group A) and >12% (group B) was performed. There was no significant difference in implantation rate (group A: 17.0%; group B: 23.2%), pregnancy rate (group A: 36.6%; group B: 47.7%) or miscarriage rate (group A: 23.3%; group B: 28.6%).

CONCLUSION

There were no significant differences between simple enumerations of peripheral blood NK cells (including total CD56(+) NK, CD56(dim) NK and CD56(bright) NK cells), B cells and T cells with IVF treatment outcome and pregnancy outcome. Women who had a peripheral NK cell level >12% did not have higher number of previous pregnancy losses. Importantly their pregnancy rate was not reduced and their miscarriages were not increased compared to women who had a peripheral NK cells level <12%.

Distributions of endometrial NK cells, B cells, T cells, and Th2/Tc2 cells fail to predict pregnancy outcome following recurrent abortion

PROBLEM

To evaluate the ability of immunophenotypes of endometrial leukocytes from patients with histories of recurrent abortion to predict outcome of subsequent pregnancy.

METHODS OF STUDY

Seventeen women with two successive spontaneous abortions with normal karyotype in the conceptus and 15 women with male-factor infertility were studied. Subsequent pregnancy outcomes in 17 recurrent abortion patients were noted; 11 had live birth, while six aborted in the first trimester. All of 15 women with male-factor infertility became pregnant after therapy, resulting in live birth in all cases. Endometrium was sampled during the peri-implantation period before subsequent pregnancy. We immunostained paraffin-embedded sections for lymphocyte markers including natural killer (NK) cell markers, CD56 and CD16, a B-cell marker CD20, T-cell markers CD3 and CD8, and a specific T-helper(Th)2 and T-cytotoxic (Tc)2 marker termed 'chemoattractant receptor-homologous molecule expressed on Th2 cells' (CRTH2). Immunoreactive cells for these antigens were counted and positivity ratios to CD45- or CD3-positive cells were calculated. These parameter were compared between 17 patients with histories of recurrent abortion and 15 control women and also compared between 11 patients whose subsequent pregnancy was successful and six patients whose subsequent pregnancy was a failure.

RESULTS

Numbers of CD45+, CD56+, CD16+, CD20+, CD3+, CD8+, and CRTH2+ cells in recurrent abortion patients resembled those in controls. No significant difference in lymphocyte subset numbers or ratios was noted between patients whose subsequent pregnancy was successful and those who again aborted.

CONCLUSION

We could not predict pregnancy outcome by immunophenotypic analysis of endometrium in women with recurrent abortion.

Distribution of Th1 and Th2 cell populations in human peripheral and decidual T cells from normal and anembryonic pregnancies

OBJECTIVE

To examine whether maternal immune responses during normal pregnancy are Th2 biased and whether there are specific changes when anembryonic pregnancy occurs.

DESIGN

Prospective study.

SETTING

Department of Obstetrics and Gynecology at a university hospital.

PATIENT(S)

We studied 32 pregnant women receiving elective abortions of normal pregnancies and 35 women with anembryonic pregnancies between 6 weeks and 10 weeks of gestational age.

INTERVENTION(S)

Using the multilabeling capability of three-color flow cytometry, it is possible to measure intracellular cytokines and cell surface markers simultaneously to determine which cells are the cytokine-producing cells.

MAIN OUTCOME MEASURE(S)

We examined the extent and proportion of mononuclear cells expressing specific T-cell surface markers and cytokines, interferon gamma, and interleukin 4 in the peripheral blood and deciduae. Secreted cytokines in the supernatants after 24-hour culture were also compared.

RESULT(S)

During the unstimulated status, the proportion of IL-4-secreting cells significantly exceeded that of IFN-gamma-secreting cells in the peripheral blood and decidua in normal pregnancies and was significantly decreased when anembryonic pregnancies occurred. Consequently, the Th1/Th2 ratios were increased during anembryonic pregnancies. However, after 24-hour culture, only another Th2-type cytokine, IL-10, was markedly increased and exceeded IFN-gamma secretion in cultures from both the peripheral blood and decidua in normal pregnancies.

CONCLUSION(S)

The decidual T lymphocytes are Th2 predominant. When anembryonic pregnancy occurs, this Th2 predominance disappears.