Interferon-γ Expression in Natural Killer Cells and Natural Killer T Cells Is Suppressed in Early Pregnancy

Recent study has suggested that innate immune system might play an important role in pregnancy progression. In this study, to investigate whether NK cells and NKT cells, instead of T cells, are the dominant populations of peripheral blood in early pregnancy, flow cytometry was used to detect the percentage and intracellular cytokine expressions of T cells, NK cells, NKT cdls in peripheral blood of non-pregnant women and early pregnant women. In our result, the percentages of NK calls and NKT calls were significantly increased in pregnancy compared to non-pregnancy. However, the percentage of T cells was not changed. We did not detect the Th2-dominance of total lymphocytes or T cells in peripheral blood of early pregnant women and there were also no significant changes of type 1 and type 2 cytokines in T cells, but IFN-γ production in both NK and NKT cells was decreased in early pregnancy. These results suggest that the innate immune system including NK cells and NKT cells should play a pivotal role in pregnancy progression. Type 1/type 2 shift mechanisms in innate immune system during the human early pregnancy should be paid more attention.     

Women with Pre-Eclampsia Have an Altered NKG2A and NKG2C Receptor Expression on Peripheral Blood Natural Killer Cells

Problem  Preeclampsia, a pregnancy disorder, is associated with exaggerated inflammation and increased serum monokines. Uterine natural killer (NK) cells are implicated in preeclampsia pathology, but little is known regarding peripheral NK cells in the disease.
Method of Study  We examined blood NK cells at delivery in women with preeclampsia, in healthy pregnant women and in healthy non-pregnant blood donors as a reference.
Results  Although the percentages of both NKG2A- and NKG2C-positive NK cells were normal in preeclamptic women, the levels of NKG2A and NKG2C on NK cells were significantly up-regulated in these women. In vitro stimulation of PBMCs from healthy pregnant women and blood donors with monokines resulted in increased percentage of NKG2A⁺ NK cells and increased NKG2A levels, while levels of NKG2C were decreased.
Conclusions  Our results suggest that the peripheral NK-cell pool is skewed in preeclampsia and possibly under the influence of monokines like interleukin (IL)-15 and IL-12.     

Immunoregulatory factors in multiple sclerosis patients during and after pregnancy: relevance of natural killer cells

Multiple sclerosis (MS) ameliorates typically during pregnancy but after the delivery the relapse rate often increases. Our study was conducted to understand the immunoregulatory mechanisms accompanying this phenomenon. MS patients were followed-up prospectively during pregnancy and 6 months postpartum, with immunological characterization of the peripheral blood. Groups of age- and parity-matched healthy pregnant women, and age- and sex-matched non-pregnant women and non-pregnant MS patients were studied as controls. In our patient cohort, the annualized relapse rate was 1.0 +/- 1.0 relapses/woman/year (mean +/- standard deviation) during the year before pregnancy, but dropped to 0.2 +/- 0.9 during the third trimester (P = 0.02). After the delivery the relapse rate increased again to 1.4 +/- 1.9 (1-3 months postpartum versus third trimester P = 0.003). While percentages of peripheral blood CD3, CD4, CD8 and CD19 immune cell subsets were unchanged over the observation period, reduced disease activity during the last trimester was associated with a significant increase in the percentage of circulating CD56(bright) natural killer (NK) cells. Simultaneously, the proportion of circulating CD56(dim) NK cells was clearly reduced. No alteration was noted in CD4+ CD25(high) forkhead box P3+ regulatory T cells. Production of interferon-gamma by peripheral blood lymphocytes was down-regulated significantly during pregnancy in comparison to the postpartum period, resulting in an increased T helper type 2 (Th2) : Th1 ratio during pregnancy. In conclusion, pregnant state in MS patients is characterized by an increase in the percentage of CD56(bright) NK cells and by enhanced Th2 type cytokine secretion. Our findings suggest a potential role for CD56(bright) regulatory NK cells in the control of autoimmune inflammation during pregnancy in MS.     

复发性自然流产患者外周血自然杀伤细胞免疫表型检测

目的 检测复发性自然流产(RSA)患者外周血自然杀伤(NK)细胞的免疫表型。方法 应用流式细胞术检测27例RSA妊娠患者、41例RSA非妊娠患者、32例正常妊娠者和25例正常非妊娠者外周血CD56dimCD 16+、CD56brightCD16+/-、CD69+、HLA-DR+ NK细胞表达并进行比较。结果RSA妊娠组、RSA非妊娠组、正常妊娠组和正常非妊娠组外周血CD56dimCD16+ NK细胞占总NK细胞的比例分别为(88.69.±5.86)％、(79.25±9.31)％、(79.24±10.09)％、(75.49±11.96)％;CD56brightCD16+/- NK细胞的比例分别为(8.18±5.54)％、( 12.20±6.49)％、( 13.13±8.65)％、( 11.53±6.23)％;CD69+ NK细胞的比例分别为(3.42±2.13)％、(2.36±1.72)％、(2.68±1.81)％、(2.08±1.73)％;HLA-DR+ NK细胞的比例分别为(15.26±9.32)％、(9.96±7.18)％、( 10.57±8.05)％、(9.64±6.12)％。与RSA非妊娠组、正常妊娠组及正常非妊娠组比较,RSA妊娠组CD56dimCD16+、CD69+、HLA-DR+ NK细胞显著升高（均P＜0.05）。与RSA非妊娠组及正常妊娠组比较,RSA妊娠组CD56brightCD16+/- NK细胞明显降低（均P＜0.05）。结论 RSA妊娠患者外周血中NK细胞CD56dimCD16+、CD69+和HLA-DR+表达增高,而CD56brightCD16+/-表达下降,可能在RSA的发生发展中起着一定的作用。     

Commitment of decidual haematopoietic progenitor cells in first trimester pregnancy

PROBLEM The aim of this study was to investigate the phenotype and commitment of decidual haematopoietic progenitor cells (HPCs) in healthy pregnant women and in women with early miscarriage. METHOD OF STUDY Peripheral blood and decidual tissue from healthy and pathological pregnant women were examined for HPCs and lymphoid progenitors using flow cytometric analysis. RESULTS Compared with peripheral blood, we found a significant increase in decidual HPCs in both healthy pregnant women and women with spontaneous abortion. T/NK, natural killer (NK), gamma-delta and NKT cell progenitors were identified in all peripheral blood and decidual samples. In pathologic pregnant women, the ratios of decidual T/NK and NK cell progenitors were significantly increased compared with healthy pregnant controls. CONCLUSION We demonstrated decidual cells with haematopoietic progenitor cell phenotype in human decidua. Increased levels of NK progenitors in the decidua of women with early spontaneous abortion suggest a dysregulation of this pathway that may contribute to pregnancy failure.     

High levels of peripheral blood NK cells in women suffering from recurrent spontaneous abortion are reverted from high-dose intravenous immunoglobulins

PROBLEM: To determine the levels of peripheral blood natural killer (NK) cells in healthy women and recurrent aborters, and the effect of intravenous immunoglobulins (IVIGs) on these levels. METHOD OF STUDY: A total of 659 women were evaluated for NK cells by means of flow cytofluorimetry: 42 non-pregnant healthy women, 394 non-pregnant recurrent spontaneous abortion (RSA) women, 36 pregnant healthy women and 187 pregnant RSA women. Fifty-four of the pregnant RSA women were treated with IVIG; in 18 of them NK cells were measured immediately before and after the very first IVIG infusion (0.5 g/kg body weight). RESULTS: Blood NK cell results were increased in RSA pregnant/non-pregnant women, and significantly reduced by IVIG, even after the very first infusion. In RSA pregnant women treated by means of IVIG therapy, 92.3% success rate was observed. CONCLUSIONS: High levels of NK cells are detected in women affected by RSA. IVIGs are capable of decreasing them with a short- and long-term efficacy, allowing having a very high success rate of pregnancies in RSA women.     

The role of gamma/delta T-cell receptor-positive cells in pregnancy: part II.

PROBLEM: We have previously demonstrated a significantly increased ratio of gamma/delta T-cell receptor (TCR)-positive progesterone receptor(PR)-positive cells in the peripheral blood of healthy pregnant women compared to that of recurrent aborters or non-pregnant individuals. Treatment of pregnancy lymphocytes with a pan anti-gamma/delta TCR antibody inhibits progesterone-induced blocking factor (PIBF) production, increases natural killer (NK) activity, and alters the cytokine profile. The present study was aimed at investigating the role of the different gamma/delta subpopulations in these phenomena. METHOD OF STUDY: Peripheral blood lymphocytes from healthy pregnant women were incubated with either anti-gamma1.4 and delta1, or anti-gamma9 and delta2 antibodies. The effect of these treatments on PR induction and interleukin (IL)-10 and IL-12 expression were tested by immunocytochemistry. NK activity of anti-gamma/delta treated lymphocytes was also determined. RESULTS: In peripheral blood of healthy pregnant women, the most frequently occurring chain combination was gamma1.4/delta1, whereas in recurrent aborters, the gamma9/delta2 combination was predominant. Treatment of normal pregnancy lymphocytes with a mixture of gamma1.4 and delta1 antibodies resulted in a significantly reduced NK activity and increased PR and IL-10 expression, whereas treatment with a mixture of gamma9 and delta2 antibodies significantly reduced IL-10 production and slightly increased IL-12 production and NK activity. These data suggest the presence of two functionally distinct subpopulations in the peripheral blood of pregnant women.     

Trophoblast cell influence on peripheral blood natural killer cell proliferation and phenotype in non-pregnant women and women in early pregnancy

Natural killer (NK) cells are the main population of leukocytes in decidua during the first trimester of pregnancy. NK cells can have contact with trophoblast cells during pregnancy, which raises the possibility of mutual influence. This research aimed to evaluate the proliferation and phenotype of peripheral blood NK cells in the presence of trophoblast cells of the JEG-3 cell line. We showed that trophoblast cells of the JEG-3 cell line (American Type Culture Collection (ATCC), USA) produced TGFβ. However, co-culturing of NK and trophoblast cells did not change the SMAD2/3 to pSMAD2/3 ratio within NK cells. These data indicate that the canonical signaling pathway from TGFβ is not activated, but do not preclude activation of SMAD-independent signaling pathways through the effect of TGFβ and/or other cytokines. We established that trophoblast cells inhibited both constitutive and IL-2-induced expression of Ki-67 proliferation marker by NK cells in vitro in both pregnant and non-pregnant women. Constitutive and induced Ki-67 expression by peripheral blood NK cells was increased in pregnant women compared with non-pregnant women. The influence of trophoblast cells on Ki-67 expression by NK cells was more pronounced in the presence of other mononuclear cells than in their absence. In the presence of trophoblast cells and IL-2, the number of NK cells with the CD16+CD57- phenotype in peripheral blood mononuclear cells (PBMCs) was increased in pregnant and non-pregnant women, compared with culturing with IL-2 only. This might reflect a decrease in the number of NK cells at the terminal stage of differentiation. We also revealed the increased content of NK cells with the CD16-CD56bright phenotype in PBMCs of pregnant women when incubated with trophoblast cells and IL-2, compared with culturing with trophoblast cells only. Our results suggest that NK cells need contact interactions with trophoblast cells and additional cytokine stimulation (IL-2, cytokines of other mononuclear cells) to acquire the CD56bright phenotype.     

Lack of soluble TNF-receptors in women with recurrent spontaneous abortion and possibility for its correction

PROBLEM: Tumor necrosis factor (TNF) and soluble TNF receptors (sTNF-Rs) system related with Th1 and Th2 and activity of NF-kappaB/IkappaB regulatory system. This study was designed to compare sTNF-R1 and sTNF-R2 production (shedding) and levels of late activated CD8+ T-lymphocytes in non-pregnant (n = 30) and pregnant (n = 20) normal women and non-pregnant (n = 20) and pregnant (n = 30) RSA women. Effects of progesterone (natural structure) injections in RSA women were studied. METHODS OF STUDY: Levels of sTNF-R1, sTNF-R2, TNF in peripheral blood serum were detected by enzyme-linked immunosorbent assay. Lymphocyte subsets were estimated by multicolor flow cytometry. NK cell cytotoxic activity of peripheral blood lymphocytes (PBL) in whole blood against K562 targets was determined using Europium-release cytotoxicity assay. Mitogen-induced proliferative response of PBL to PHA-P, Con A and PWM were determined by standard 3H-thymidine incorporation assay. RESULTS: Levels of soluble TNF-R1 and TNF-R2 in normal pregnancy were elevated when compared with non-pregnant normal women and pregnant RSA women. Levels of late activated CD8+ T-lymphocytes in normal pregnancy were decreased but no changes were detected in RSA women. After progesterone therapy (i.m. injections of 2.5% oil solution) in RSA women elevation of sTNF-R1 and sTNF-R2 to normal pregnancy ranges was observed. No changes in levels of late activated CD8+ T-lymphocytes after progesterone treatment were detected. CONCLUSIONS: Elevation of levels of sTNF-R1, sTNF-R2 and decrease of late activated cytotoxic T-lymphocytes are pronounce markers of normal human pregnancy. In RSA women there are no elevation of sTNF-R1 and sTNF-R2 levels during pregnancy. This deficiency may be restored by progesterone treatment.     

Natural killer cells in normal pregnancy: analysis using monoclonal antibodies and single-cell cytotoxicity assays.

Peripheral blood lymphocytes (nylon wool non-adherent) from healthy pregnant women and normal non-pregnant females were tested for natural killer (NK) cell-mediated cytotoxicity against K562 target cells both by 51Cr-release assay and single-cell cytotoxicity assay in agarose. The results indicated depression of NK cytotoxicity in pregnancy due to a decrease in the proportion of target-binding lymphocytes as well as a reduction in the lytic capacity of target-bound cells. The ability of active pregnancy-associated NK lymphocytes to recycle appeared to be unimpaired. Analysis of lymphocyte populations with monoclonal antibodies recognizing NK cell-associated antigens showed that the number of Leu-11+ lymphocytes was reduced in pregnancy. Enumeration of Leu-7+ cells and correlation of NK cell subpopulation data with cytotoxicity assay data suggest that pregnancy is associated with a reduction in the number of mature NK cells and probably also an inhibition of post-binding lytic activity.     

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%.     

Changes in systemic type 1 and type 2 immunity in normal pregnancy and pre-eclampsia may be mediated by natural killer cells

A bias of T cell immunity towards type 2 (Th2) is thought to be critical for normal pregnancy. Pathological pregnancies, such as pre-eclampsia, are characterised by cell-mediated (Th1) immune dominance. The Th1/Th2 paradigm, however, is too simplistic. Normal pregnancy is associated with a systemic inflammatory response which increases throughout gestation. This inflammatory response is exaggerated in pre-eclampsia, a syndrome of the third trimester. T helper (Th) cells are considered the primary mediators of these altered immune responses, and other T cells, i.e. T cytotoxic (Tc) cells, and lymphocytes of the innate immune system, i.e. natural killer (NK) and NKT cells, have been largely disregarded. In this study, we have used novel pan type 1 (IL-18 receptor) and pan type 2 (ST2L) lymphocyte function markers in four-colour flow cytometry to broadly characterise peripheral blood lymphocyte populations from non-pregnant, normal pregnant and pre-eclamptic women. There were no changes in the Th1/Th2 or Tc1/Tc2 cell ratios between the three groups; however, the NK1/NK2 and NKT1/NKT2 cell ratios were significantly decreased in normal pregnancy compared with non-pregnant (p <0.001 and p <0.01, respectively) and pre-eclamptic women (p <0.05). These results confirm that immunoregulation occurs in pregnancy, but suggest a dominant role of the innate rather than the adaptive immune system.     

SHORT COMMUNICATION: Circulating and Decidual Th17 Cell Levels in Healthy Pregnancy

Citation Nakashima A, Ito M, Yoneda S, Shiozaki A, Hidaka T, Saito S. Circulating and decidual Th17 cell levels in healthy pregnancy. Am J Reprod Immunol 2010; 63: 104–109 Problem The Th1/Th2 paradigm has recently been reconstituted to include a third population, Th17 cells. It has been reported that Th2 type immunity is predominantly present in normal pregnancy. However, the level of Th17 cells during pregnancy is still unclear. We investigated the level of peripheral Th17 cells in healthy pregnancy subjects. Method of study To evaluate the levels of Th17 cells, we investigated the proportion of peripheral blood mononuclear cells that produced IL‐17 in the first, second, and third trimester pregnancy subjects using flow cytometry. We further studied the proportion of decidual lymphocytes that produced IL‐17 in early pregnant subjects. Results Most of the IL‐17‐producing cells were CD4⁺ T cells. The number of circulating Th17 cells did not change during pregnancy. In a paired t‐test of early normal pregnant subjects, the proportion of IL‐17⁺ decidual lymphocytes was significantly higher than that of peripheral blood lymphocytes. Conclusion Th17 levels in peripheral blood lymphocytes do not change during normal pregnancy.     

Longitudinal studies showing alterations in the levels and functional response of T and B lymphocytes in human pregnancy.

Altered blood levels of T and B lymphocytes were found in the first half of human pregnancy. A total of twenty-two women were tested, using direct or indirect rosetting assays or the fluorescence-activated cell sorter, to determine the levels of peripheral blood T and B cells. In all cases, an inversion of T- and B-cell levels was observed, i.e. T-cell levels were decreased and B-cell levels (as measured by the presence of surface immunoglobulin or the presence of B-cell surface antigens) were increased. This inversion was exhibited as early as 1 week post-implantation. Lymphocytes from two fo the women were also examined for stimulation with phytohaemagglutinin (PHA) and pokeweed mitogen (PWM) at intervals during gestation, and the amount of [3H]thymidine uptake was compared to that of two non-pregnant women tested at each interval. The values obtained for the pregnant women with PHA were markedly lower, and with pokeweed mitogen slightly lower, than those of non-pregnant controls. However, the PHA and PWM values in the pregnant women returned to levels similar to those of the nonpregnant women shortly after the T- and B-cell levels returned to normal. Thus the decrease in the response of the lymphocytes to mitogens during early pregnancy appears to parallel the numerical deficiency of T cells.     

Extracellular Matrix Protein-dependent Apoptosis of T Cells in Women with a History of Recurrent Spontaneous Abortion

PROBLEM: The purpose of the study was to determine the role of T-cell apoptosis in extracellular matrix (ECM) environment in pregnancy maintenance in women with a history of recurrent spontaneous abortion (RSA). METHOD OF STUDY: Thirty-nine non-pregnant women with the history of RSA (anatomic, genetic, endocrine and microbiologic causes were excluded) and 22 healthy women with the previous successful pregnancy outcome were studied. In addition, 21 women with the history of RSA were also studied at the beginning of their next pregnancy. We studied apoptosis of peripheral blood T cells after culture with monoclonal antibody (mAb) OKT-3 alone or with mAb OKT-3 following ECM proteins: collagen IV (C-IV) or fibronectin (Fn). We used Cell Death Detection ELISA for studying cell death in cell population. In addition, apoptotic peripheral blood T cells were identified by annexin V-PE staining protocol using flow cytometry. CD29+ and CD95+ T-cell surface receptors were also analyzed by flow cytometry. RESULTS: The significantly higher values of enrichment factor: mU of the sample (dying/dead cells) per mU of the corresponding control (viable cells) were observed after peripheral blood T-cell culture with C-IV (P = 0.0002) or Fn (P = 0.004) in samples of non-pregnant women with the history of RSA when compared with control women. The significantly higher values of enrichment factor were observed after peripheral blood T-cell culture with C-IV in samples of pregnant women with the history of RSA with successful pregnancy outcome when compared with pregnant women with the history of RSA with failed pregnancy outcome (P = 0.01). However, the percentage of apoptotic T cells stained by annexin V was significantly lower in non-pregnant RSA women compared with control (P = 0.0001). CD95 expression was significantly lower in non-pregnant RSA women compared with control (P = 0.01). CONCLUSIONS: Apoptosis of T cells might be an interesting possible explanation of successful pregnancy outcome in women with the history of RSA.     

CD4+CD25+Foxp3+调节性T细胞在子痫前期患者外周血与蜕膜中水平变化研究

目的本文检测CD4+CD25+Foxp3+调节性T细胞在子痫前期患者外周血及胎盘附着处蜕膜中的表达,探讨其在子痫前期免疫耐受失衡中的作用。方法选择子痫前期患者20例,正常晚期妊娠患者20例。采用流式细胞仪检测外周血CD4+CD25+Foxp3+的表达;免疫组织化学法检测蜕膜CD4+CD25+调节性T细胞的特异性转录因子Foxp3的表达。结果 1.子痫前期组外周血CD4+CD25+Foxp3+T细胞表达率(1.70±0.23%)明显低于正常晚期妊娠对照组(3.55±0.47%)(P<0.05)。2.蜕膜中Foxp3在子痫前期组的表达阳性率为(16.67%)明显低于正常对照组(66.67%)(P<0.05)。结论子痫前期患者外周血和蜕膜组织中的CD4+CD25+Foxp3+调节性T细胞均低于正常孕妇,提示其数量的减少使其免疫抑制功能减弱,母胎免疫耐受失衡,导致子痫前期的发生。     

Monocytes are primed to produce the Th1 type cytokine IL-12 in normal human pregnancy: an intracellular flow cytometric analysis of peripheral blood mononuclear cells

This paper considers both monocytes and peripheral blood lymphocytes as potential targets for maternal immunological modulation in pregnancy. Peripheral blood mononuclear cells (PBMCs) from non-pregnant and normal pregnant donors were stimulated in vitro, and cytokine production detected intracellularly by flow cytometry. It was found that monocyte production of TNF-alpha was unaltered in pregnancy, while production of IL-12 was significantly enhanced. In contrast, production of the Th1 type cytokine IFN-gamma was suppressed in the lymphocyte subsets: CD4+ T helper cells and CD56+ NK cells. Production of the Th2 type cytokine IL-4 in CD4+ cells was not significantly altered in pregnancy. These data suggest that the concept that pregnancy is a 'Th2 phenomenon' cannot be generalized to the function of all aspects of maternal cellular immunity as, paradoxically, circulating monocytes are 'primed' to produce the Th1 cytokine IL-12. Furthermore, these data support the hypothesis that components of maternal innate immunity are activated in normal pregnancy.     

Accumulation of CD16+ cells with secretion of Ksp37 in decidua at the end of pregnancy

PROBLEM: Maternal cellular immunity is thought to be in a state of tolerance during pregnancy, but the precise mechanism of immunomodulation is not yet known. We investigated a novel serum protein, killer-specific secretory protein of 37 kDa (Ksp37), produced by cytotoxic lymphocytes, during pregnancy. METHOD OF STUDY: The level of Ksp37 was determined by enzyme linked immunosorbent assay (ELISA) in the sera of healthy pregnant women. Intracellular Ksp37 expression in mononuclear cells, isolated from peripheral blood and decidua at parturition, was examined with a flow cytometer. RESULTS: Serum Ksp37 levels significantly increased at late pregnancy, compared with non-pregnant controls and the first trimester of pregnancy. The flow cytometric analysis exhibited that Ksp37 was mainly expressed in CD16+ natural killer (NK) cells in decidua of term placenta. CONCLUSIONS: Serum Ksp37 level was elevated at late gestational period. CD16+ NK cells in decidua seem to be a main maternal source of Ksp37. Innate immunity, with CD16+ NK cells, may play important roles near parturition.     

Aberrant cytokine production by peripheral blood mononuclear cells in recurrent pregnancy loss?

BACKGROUND: Successful pregnancy may depend on a Th2-type cytokine response, whilst, conversely, a poor pregnancy outcome may be associated with an increase in Th1 cytokines and a concomitant decrease in Th2 cytokines. This prospective study was designed to elucidate whether a failure of the cytokine shift pre-dated miscarriage and was therefore likely to be an aetiological factor in recurrent pregnancy loss (RPL). METHODS: Cytokine production by stimulated peripheral blood mononuclear cells from 46 pregnant women who had previously suffered idiopathic RPL during early pregnancy was compared with 25 gestationally age-matched pregnant controls and 11 non-pregnant women. RESULTS: Production of IFN-gamma was lower in pregnant than in non-pregnant women and even lower in RPL pregnant women (P = 0.0191). IL-10 was increased in pregnant women compared with non-pregnant controls, and further increased in RPL patients (P = 0.026). IL-4 was also increased in women with RPL (P = 0.0001). No differences in IFN-gamma, IL-10 or IL-4 secretion were observed in RPL patients who subsequently miscarried compared with those who successfully completed the pregnancy. RPL women with a successful reproductive outcome had similar concentrations of TNF-alpha to pregnant women, RPL women who subsequently miscarried had significantly lower levels than either pregnant women (P = 0.02) or non-pregnant controls (P = 0.0004). CONCLUSIONS: Contrary to our hypothesis, the cytokine shift, which appears to characterize normal pregnancy, was accentuated rather than diminished in RPL pregnant women.     

CD4+ CD25+ regulatory T cells in human pregnancy: development of a Treg-MLC-ELISPOT suppression assay and indications of paternal specific Tregs

The current study was aimed at developing a one-way mixed leucocyte culture-enzyme-linked immunospot (MLC-ELISPOT) assay for the study of CD4(+) CD25(+) regulatory T (T(reg)) cells and applying this method in the study of antifetal immune reactions during human pregnancy. Twenty-one pregnant women and the corresponding fathers-to-be, and 10 non-pregnant control women and men, participated in the study. CD4(+) CD25(+) cells were isolated from peripheral blood mononuclear cells (PBMC) by immunomagnetic selection. Maternal/control PBMC were stimulated with paternal or unrelated PBMC in MLC. Secretion of interleukin-4 (IL-4) and interferon-gamma (IFN-gamma) from responder cells, with or without the presence of autologous T(reg) cells, was analysed by ELISPOT. PBMC from pregnant women showed increased secretion of IL-4 compared to controls. In pregnant and non-pregnant controls, T(reg) cells suppressed IFN-gamma reactivity against paternal and unrelated alloantigens. Interestingly, T(reg) cells suppressed IL-4 secretion against paternal but not unrelated alloantigens during pregnancy. We have successfully developed a model for studying T(reg) cells in antifetal cytokine reactions during pregnancy. Results indicate that T(reg) cells contribute to strict regulation of both T helper type 1-like and type 2-like antifetal immune reactions. Interestingly, T helper type 2-like cells specific to unrelated alloantigens are able to escape the suppression of T(reg) cells, which would allow for IL-4, alongside CD4(+) CD25(+) T(reg) cells, to control potentially detrimental IFN-gamma reactions during pregnancy.