CD4(+)CD25+ T regulatory cells in murine pregnancy

Mammalian pregnancy is thought to be a state of immunological tolerance and immunological pregnancy complications may result from incomplete allo-tolerance. We reported recently a higher frequency of Th1 cytokine-producing T cells specific against paternal antigens in abortion-prone mice compared to normal pregnant mice. Since Th2 cells were shown to be not essential for normal pregnancy; alloreactive Th1 cells must be differently regulated. In this context, T regulatory cells (Treg) were proposed to play an essential role. Normal pregnant mice show an expansion of CD4(+)CD25+ and IL-10+ Treg cells at the periphery compared to non-pregnant animals. Further, we reported significantly lower frequencies of Treg in abortion-prone mice. Interestingly, CD4(+)CD25+ Treg cells from normal pregnant mice were able to prevent fetal rejection. Accordingly, down-regulated levels of Treg were also reported during human miscarriage. The putative mechanisms involved in Treg-induced tolerance in mice and humans are discussed in this review.     

卵巢早衰患者外周血CD4~+CD25~+Treg细胞的变化及意义

目的:探讨CD4+CD25+调节性T细胞(即CD4+CD25+Treg细胞)在卵巢早衰发病机制中的作用。方法:流式细胞仪定量检测卵巢早衰(premature ovarian failure,POF)患者、卵巢储备功能下降(diminished ovarian reserve,DOR)患者及健康对照组外周血CD4+T、CD8+T细胞及CD4+CD25+Treg细胞数量,应用3H-thymidine掺入法测定POF患者及对照组外周血CD4+CD25+Treg细胞对效应性T细胞的增殖抑制功能。结果:与对照组相比,POF患者及DOR患者CD4+CD25+Treg细胞比例降低(P<0.01)、POF患者CD4+T/CD8+T细胞比值增高(P<0.05),DOR患者CD4+T/CD8+T细胞比值无明显变化(P>0.05);POF患者免疫抑制功能无明显降低(P>0.05)。结论:CD4+CD25+Treg细胞比例降低与T细胞亚群失衡可能是POF的发病机制。     

Fetal alloantigen is responsible for the expansion of the CD4(+)CD25(+) regulatory T cell pool during pregnancy

Increasing evidence suggests that CD4(+)CD25(+) regulatory T cells (Tregs) participate in the development of maternal tolerance to the fetus during pregnancy; however, the factors controlling the activities of Tregs are poorly understood. In the present study, CD4(+)CD25(+) Tregs were analyzed in syngeneically pregnant mice (BALB/cxBALB/c), allogeneically pregnant mice (BALB/cxC57), ovariectomized mice and pregnant women to investigate the influences of fetal alloantigens and pregnancy-related hormones on the activities of Tregs. It was demonstrated that the frequencies of CD4(+)CD25(+) Tregs increase more in allogeneically than in syngeneically pregnant mice, which contributes to a lowered alloreactivity against paternal antigens in allogeneically compared with syngeneically pregnant mice. The increased Tregs are most likely to be induced in peripheral lymphoid tissues, rather than develop in thymus. Allogeneically mated mice and humans share similar dynamic changes in Treg frequencies, markedly increasing during early pregnancy and progressively decreasing from mid-gestation onwards to return to non-pregnant levels at term. Induction of labor in humans appears to be associated with a decrease of CD4(+)CD25(high) Tregs and increase of CD4(+)CD25(low) T cells. Neither estrogen or progesterone alone, nor their combination, shows an impact on the frequencies of Tregs in ovariectomized mice. These results suggest that fetal alloantigen is responsible for the increase of Tregs during pregnancy, and the expansion of the Treg population is of importance for the allogeneic fetus to evade immune attack from the mother.     

Blockade of CD80 and CD86 at the time of implantation inhibits maternal rejection to the allogeneic fetus in abortion-prone matings

CD28/CTLA-4 interactions with their specific B7-ligands (CD80 and CD86) play a decisive role in antigenic and allogenic responses. Recently, experimental transplant studies demonstrated that donor-specific tolerance was achieved by blocking these interactions. However, the role of blockade of CD28/B7 costimulatory pathway in the maintenance of materno-fetal tolerance has received little attention. In the present study, abortion-prone CBA/J females mated with DBA/2 males were administered with anti-CD80 and anti-CD86 monoclonal antibodies (mAbs) on day 4 of gestation (time of murine implantation). We demonstrated that the combined use of anti-CD80 and anti-CD86 mAbs induced maternal tolerance to the fetus in the abortion-prone CBA/J mice, and displayed expansion of the maternal CD4(+)CD25+ regulatory T cell population and up-regulated expression of CTLA-4, suggesting an active mechanism of regulatory T cells in suppressing maternal rejection to the fetus. In addition, the anti-CD80/86 mAbs treatment enhanced Th2 and reduced Th1 cytokine production in mice, implying that the development of Th2 cells might contribute to maternal tolerance to her fetus. Together, these findings indicated that blocking CD80 and CD86 enhanced maternal tolerance to her fetus in mice by increasing regulatory T cell function and skewing toward a Th2 response. Our data might provide an enhanced understanding of the maternal-fetal immune relationship and be helpful in clinical trials for immunotherapy of recurrent spontaneous abortion.     

What is the role of regulatory T cells in the success of implantation and early pregnancy?

Problem The immune system is well controlled by the balance between immunostimulation and immunoregulation. CD4⁺CD25⁺ regulatory T (Treg) cells and an enzyme called indoleamine-2, 3-dioxygenase (IDO) mediate maternal tolerance of the allogeneic fetus. Treg cells, therefore, may prevent early pregnancy loss due to maternal ‘rejection.’ Methods The latest understanding of tolerance during pregnancy is reviewed. Results and conclusions Recent data show that CD4⁺CD25⁺ Treg cells play essential roles in the induction and maintenance of tolerance, and that they augment the IDO activity in dendritic cells and macrophages. Therefore, CD4⁺CD25⁺ Treg cells and IDO enzyme may cooperate in the induction of tolerance during pregnancy. Treg deficiency is associated with very early post-implantation loss and spontaneous abortion in animal models, and low Treg levels are associated with recurrent miscarriages in humans.     

原因不明复发性流产患者蜕膜CD4~+CD25~+CD127~(dim/-) Treg细胞的表达频率和功能研究

目的:探讨原因不明复发性流产(URSA)患者母胎界面免疫耐受环境的变化。方法:留取URSA患者21例(URSA组)和30例正常早孕人流妇女(对照组)蜕膜组织,制备成单个核细胞悬液,流式细胞术分析CD4+CD25+CD127dim/-Treg细胞的表达频率;取两组蜕膜单个核细胞悬液各5例,用免疫磁珠分离法分离出CD4+CD25+CD127dim/-Treg细胞,流式细胞术分析CD4+CD25+CD127dim/-Treg细胞内IL-10和TGF-β的表达水平;体外增殖抑制试验分别检测用抗IL-10抗体和抗TGF-β抗体处理的CD4+CD25+CD127dim/-Treg细胞,和未用抗体处理的CD4+CD25+CD127dim/-Treg细胞对自身效应T细胞增殖的抑制作用。结果:URSA组蜕膜CD4+CD25+CD127dim/-Treg细胞的表达频率明显低于对照组(P=0.005);URSA组蜕膜CD4+CD25+CD127dim/-Treg细胞内IL-10和TGF-β表达频率均较对照组明显降低(P=0.04,P=0.01);URSA组CD4+CD25+CD127dim/-Treg细胞对自体效应性T细胞的增殖抑制作用显著低于对照组(P0.05),且抗IL-10抗体和抗TGF-β抗体可部分阻断蜕膜CD4+CD25+CD127dim/-Treg细胞的免疫抑制功能(P均0.05)。结论:URSA患者蜕膜CD4+CD25+CD127dim/-Treg细胞不仅表达频率降低,而且免疫抑制功能也减弱,且这种免疫抑制功能的减弱主要受IL-10和TGF-β介导,揭示CD4+CD25+CD127dim/-Treg细胞对URSA患者蜕膜局部免疫耐受环境产生影响。     

The predominance of Th17 lymphocytes and decreased number and function of Treg cells in preeclampsia

The aim of this study was to estimate the prevalence of CD3(+)CD4(+) T lymphocytes producing IL-17, IL-2, IFN-γ, and IL-4, plus CD4(+)CD25(+)FoxP3(+) T regulatory (Treg) cells, in peripheral blood of patients with preeclampsia and healthy women in the third trimester of normal pregnancy. Another purpose was to assess the immunosuppressive activity of Treg cells from patients with preeclampsia compared with controls. Thirty-four preeclampsia patients and 27 healthy pregnant women were included. The percentages of CD4(+)CD25(+)FoxP3(+) Treg cells and CD3(+)CD4(+) T lymphocytes with intracellular expressions of cytokines were estimated using monoclonal antibodies and flow cytometry. In vitro functional assays were performed using a Treg Cell Isolation Kit and (3)H-thymidine incorporation assays. The percentage of CD3(+)CD4(+) T lymphocytes producing IL-17A was significantly higher in preeclampsia than in healthy, normotensive pregnant women in the third trimester (p<0.001). The population of CD4(+)CD25(+)FoxP3(+) Treg cells was significantly lower in the study group compared with controls (p<0.05). There was no change in the stimulation index of CD3(+)CD4(+)CD25(-) T lymphocytes from preeclampsia patients without Treg cells and after addition of autologous Treg cells. In normal pregnancy, the stimulation index of CD3(+)CD4(+)CD25(-) T lymphocytes was significantly higher without Treg cells compared with the response after addition of autologous Treg cells (p<0.05). The results suggest up-regulation of the Th17 immune response in preeclampsia. The decreased number and function of Treg cells may be responsible for activating the inflammatory response characteristic of this disorder. In preeclampsia, the predominance of Th17 immunity could act through modulating the Th1/Th2 immune balance.     

Inadequate tolerance induction may induce pre-eclampsia

The fetus is semi-allograft to the maternal host; therefore, a system of tolerance must be present during pregnancy. Epidemiological findings support a relationship between pre-eclampsia and the failure of tolerance induction. For induction of major histocompatibility complex (MHC) class I-specific tolerance, long-term exposure to seminal fluid, which contains paternal soluble MHC class I antigens, may induce paternal MHC class I-specific tolerance. Furthermore, soluble HLA-G1, which induces the deletion of CD8(+) T-cells, and the combination of maternal killer-immunoglobulin-like receptors (KIR) on NK cells and fetal HLA-C, which affects the balance between inhibition and activation signals of NK cells, regulatory CD8(+) T cells, and regulatory NK cells, may play very important roles in the induction of MHC class I-specific tolerance. On the other hand, exposure to sperm, which express paternal HLA-DR, and trophoblastic debris, which contain intracellular fetal HLA-DR, may induce paternal MHC class II-specific tolerance. In this process, CD4(+)CD25(+) regulatory T (Treg)-cells play central roles. In this review, we discuss the relationship between the risk of pre-eclampsia and tolerance induction.     

CD4+CDhigh25调节性T淋巴细胞在妊娠肝内胆汁淤积症发病中的作用

目的 探讨妊娠肝内胆汁淤积症(ICP)患者外周血与蜕膜组织CD4+CD25+凋节性T淋巴细胞(Treg细胞)及CD4+CD25hJigh细胞在ICP发病中的作用.方法 采用流式细胞仪检测30例ICP患者(ICP组,其中轻度15例,重度15例)及28例正常晚期妊娠妇女(对照组)外周血和蜕膜组织CD4+CD25+Treg细胞及CD4+CD25hJigh细胞占CD+T淋巴细胞的百分率,分析其与ICP发病的关系.结果 ICP组外周血CD4+CD25+Treg细胞百分率为(7.96±1.32)%,CD4+CD25high细胞了百分率为(0.78±0.22)%,均低于对照组[(17.05±2.86)%、(1.71±0.69)%],分别比较,差异均有统计学意义(P<0.01);ICP组蜕膜组织CD4+CD25+Treg细胞百分率为(17.18±2.27)%,CD+4CD25highTreg细胞百分率为(2.25±0.89)%,也均低于对照组[(32.01±3.88)%、(8.30±1.13)%],分别比较,差异也均有统计学意义(P<0.01).ICP组及对照组蜕膜组织中CD4+CD25+Treg细胞及CD4+CD25highTreg细胞百分率均高于外周血,差异均有统计学意义(P<0.01).ICP组轻度及重度患者外周血CD4+CD25+Treg细胞百分率分别为(8.74±0.96)%、(7.17±1.17)%,CD4+CD25hiithTreg细胞百分率分别为(0.89 ±0.20)%、(0.68±0.19)%,而蜕膜组织CD4+CD25+Treg细胞百分率分别为(18.43 ±1.90)%、(15.94±1.95)%,CD4+CD25highTreg细胞百分率分别为(2.62±0.72)%、(1.87±0.90)%,ICP组外周血及蜕膜组织CD4+CD25high胞及CD4+CD25+Treg细胞百分率随着病情的加重呈下降趋势,分别比较,差异均有统计学意义(P<0.05).结论 CD4+CD25+Treg细胞及CD4+CD25+highTreg细胞可能参与ICP的发病过程,并与病情的严重程度密切相关.     

CD4~+CD25~+FOXP3~+调节性T淋巴细胞数量及功能变化与子宫内膜异位症患者发病相关性研究

目的:分析子宫内膜异位症(EMs)患者在位、异位内膜及外周血内CD4~+CD25~+FOXP3~+调节性T淋巴细胞(Treg细胞)的数量、分布及功能特性,探讨Treg细胞与EMs发病之间的关系。方法:收集EMs患者在位、异位内膜组织及外周血标本,并以非内异症患者作为对照,免疫组化分析在位、异位内膜内叉头状/翅膀状螺旋转录因子3(FOXP3)阳性细胞的数量及分布变化情况,并与EMs患者的r AFS临床分期进行相关性分析。流式细胞术检测Treg细胞占外周血CD4~+T淋巴细胞的百分比,及磁珠分选外周血内CD4~+CD25~+T细胞及CD4~+CD25-T细胞,3H-thymidine法测定CD4~+CD25~+T细胞免疫抑制功能变化情况。结果:EMs、非EMs患者在位内膜内平均FOXP3阳性细胞密度并无显著差异[(76.44±62.14)/mm~2vs(50.59±20.79)/mm~2;WU=152.0,P=0.20]。进一步按月经周期行亚组分析:EMs分泌期内膜内FOXP3阳性细胞密度显著高于非EMs患者[(94.84±53.91)/mm~2vs(31.37±19.02)/mm~2;MU=43.00,P=0.03]。不同r AFS期别患者卵巢异位症病灶内FOXP3阳性细胞密度并无显著差异[I~II期:(123.00±115.00)/mm~2vs III~IV期:(111.00±108.00)/mm~2;MU=139.5,P0.05]。EMs患者外周血内Treg细胞比例显著低于非EMs患者[(0.58±0.21)%vs(1.35±0.38)%,P0.001],但EMs患者外周血CD4~+CD25~+T淋巴细胞对CD4~+CD25-T淋巴细胞增殖抑制率,与非EMs相比并无显著变化[(68.43±18.15)%vs(66.37±17.78)%,P0.05]。结论:EMs患者在位内膜内Treg细胞失去正常的周期波动性,EMs患者分泌期内Treg细胞数目增加可能与内异症发病相关。EMs患者外周血内Treg细胞比例下降,但其免疫抑制功能并无明显改变。     

CD4＋T细胞在原因不明复发性流产中的研究进展

正常妊娠有赖于母体对胚胎半同种抗原的免疫耐受,一旦免疫耐受失衡,将导致免疫排斥、免疫攻击从而导致自然流产,原因不明复发性流产被认为与母胎免疫耐受失衡有关.CD4＋T在同种异体急性排斥反应中发挥重要作用,根据所分泌的细胞因子不同,CD4＋T 细胞分为Th1、Th2、调节性T细胞（Treg）及新近发现的Th17细胞.早期研究发现母体外周血、母胎界面CD4＋T细胞增高与复发性流产密切相关.随免疫耐受机制研究的不断深入,母胎免疫耐受的研究历经Th1/Th2平衡到Treg的免疫负调控作用,再到Th17/Treg平衡.综述CD4＋T细胞在原因不明复发性流产中的研究进展.     

The unique pathophysiology of early-onset severe preeclampsia: role of decidual T regulatory cells

Immunological mechanisms play a pivotal role in the pathophysiology of preeclampsia. T regulatory cells (Treg cells, FoxP3(+)) suppress the cytotoxic T cell (CD8(+)) and natural killer (NK) cell response, thereby promoting immunological tolerance to the fetus. In peripheral blood, Treg cells are elevated during pregnancy, decrease throughout gestation, and are decreased in preeclampsia. To determine their role at the implantation site, we characterized the proportion of decidual Treg and CD8+ cells, and compared these with placental histology, villous sFlt expression, and chorionic trophoblast apoptotic index in normal and preeclamptic pregnancies. Decidua from first (n=5) and second (n=4) trimester terminations and chorioamniotic membranes, containing decidua, from term deliveries (n=14), early-onset (≤ 34 weeks) (n=12), and late-onset (>34 weeks) (n=14) severe preeclampsia were evaluated. Immunohistochemistry for CD3, CD8, and FoxP3 was performed: CD8(+) and FoxP3(+) cells were calculated as a proportion of CD3(+) cells. Placental tissue was evaluated for villous hypermaturity and sFlt staining. Chorioamniotic membranes were evaluated, via TUNEL assay, for chorionic trophoblast apoptosis. Decidual Treg cells were seen to peak in second trimester and decrease with advancing gestational age and were lower in early-onset (0.46%) compared with late-onset severe preeclampsia (3.34%) and term pregnancies (5.21%). The proportion of CD8(+) cells was higher in cases of severe preeclampsia. Early-onset severe preeclamptic cases had the highest sFlt score, placental insufficiency score, and apoptotic index. Our data suggest that early-onset severe preeclampsia has a unique pathophysiology involving defective immunoregulatory pathways, potentially causing vascular and trophoblast damage at the implantation site.     

原因不明复发性流产主动免疫治疗前后CD4+ CD25+调节性T细胞表达频率的研究

目的探讨CD4^＋CD25^＋调节性T细胞（Tr）在原因不明复发性流产（URSA）患者主动免疫治疗中的作用。方法上海交通大学医学院附属仁济医院对2004-03—2005-05就诊于门诊的18例URSA患者，采用双荧光标记流式细胞分析技术，检测其淋巴细胞主动免疫治疗前后外周血CD4^＋CD25^＋Tr细胞表达频率的变化。结果主动免疫治疗后URSA组外周血中CD4^＋CD25^＋种Tr较治疗前明显增加（P〈0．05），CD4^＋CD25^＋较治疗前降低（P〈0．05）。主动免疫治疗后，妊娠成功的妇女CD4^＋CD25^brightTr显著多于妊娠失败者。结论主动免疫治疗可提高外周血CD4^＋CD25^brightTr数量，CD4^＋CD25^brightTr可能是调控母胎界面局部免疫耐受形成的一个重要因素，有可能成为URSA患者主动免疫治疗的监测指标之一。     

TGF-β1在早孕妇女外周血和蜕膜组织中诱导生成T调节性(Treg)细胞

目的:研究TGF-β1是否能在人母-胎界面诱导生成T调节性(Treg)细胞。方法:早孕妇女外周血和蜕膜CD4+CD25-T细胞中加入不同浓度的TGF-β1(0 ng/ml、2 ng/ml、5 ng/ml、10 ng/ml)分别于培养后第2日、第4日和第6日用流式细胞仪检测培养Foxp3的表达情况,随后将诱导生成的CD4+Foxp3+T细胞与CD8+T细胞混合培养,观察后者凋亡因子CD95配体(CD95L)的表达情况。结果:体外培养中,TGF-β1可诱导早孕妇女的外周血和蜕膜CD4+CD25-T细胞生成诱导性Treg细胞,随着培养时间增加而增强诱导效应,且在TGF-β1浓度为5 ng/ml时诱导功能最强;诱导生成的CD4+Foxp3+T细胞具有促进效应细胞CD8+T细胞凋亡的功能。结论:体外培养中,TGF-β1能将人外周血和蜕膜诱导生成Treg细胞,且具有免疫抑制功能,有良好的免疫治疗前景。     

Dysregulation of macrophage activation by decidual regulatory T cells in unexplained recurrent miscarriage patients

CD4(+)CD25(+) T cells (Treg cells) and macrophages play roles in the maintenance of maternal-fetal immunological tolerance. Treg cells suppress the function of macrophages via mechanisms mediated by cell-cell contact and production of soluble factors. The purpose of this study was to investigate regulation of macrophages by Treg cells within decidua from patients with unexplained recurrent miscarriage (RM) and normal control women during early pregnancy. Treg cells and macrophages were isolated from deciduas of unexplained RM (n=15) and control women (n=15) by magnetic cell separation and co-cultured for six days. Regulation of macrophages by Treg cells was assessed in the presence and absence of neutralizing anti-TGFβ antibodies and in transwell experiments. Expression of CD80, CD86, IL10, and IFNγ by macrophages was measured by flow cytometry or ELISA. Macrophage expression of CD80 and CD86 was higher in deciduas of unexplained RM patients compared with controls whereas the expression of IL10 was lower. There was no difference in the expression of IFNγ by macrophages between the two groups. Treg cells inhibited macrophage expression of CD80, CD86 and IFNγ and increased the expression of IL10. The regulatory effects of Treg cells were abrogated in the presence of neutralizing anti-TGFβ antibodies or by transwell culture. The phenotype of macrophages therefore differed in unexplained RM patients compared with normal early pregnant subjects. Macrophage regulation by Treg cells was shown to be mediated by cell-cell contact and TGFβ and this capacity was decreased in unexplained RM patients.     

体外受精-胚胎移植反复失败患者外周血中CD4~+CD25~+Treg的表达

目的:探讨外周血中CD4+CD25+调节性T淋巴细胞(CD4+CD25+Treg)在体外受精-胚胎移植反复失败(RIF)发病机制中的作用。方法:用流式细胞分析技术检测12例RIF组、15例胚胎移植妊娠组、15例正常未孕组患者外周血中CD4+CD25+Treg的表达。结果:RIF组患者外周血中CD4+CD25+Treg的表达率为(0.80±0.56)%,低于正常未孕组的(4.05±0.91)%,两组差异有统计学意义(P<0.05);胚胎移植妊娠组患者外周血中CD4+CD25+Treg的表达率为(11.01±2.09)%,高于RIF组,两组差异有统计学意义(P<0.05)。结论:辅助生殖中反复植入失败可能与CD4+CD25+Treg的表达下降有关,这为免疫治疗提供了理论依据。     

Th17/Treg平衡与正常妊娠及子痫前期关系的研究

目的:探讨Th17及CD4+CD25+Foxp3+调节性T(regulatory T,Treg)细胞介导的免疫反应在子痫前期发病中的作用。方法:选取在山东大学齐鲁医院进行产前检查的子痫前期患者25例及正常晚孕期妇女27例,并选取育龄期健康未孕妇女20例。利用流式细胞技术检测3组患者血样中分泌IL-17的Th17及CD4+CD25+Foxp3+Treg细胞亚群占CD4+T淋巴细胞的百分比,并计算Th17/Treg比率,比较其在子痫前期与正常妊娠时的变化;再用酶联免疫吸附试验(ELISA)检测3组患者外周血中IL-17、IL-10、TGF-β1等细胞因子的表达并进行比较。结果:(1)与正常未孕组及正常妊娠组相比,子痫前期患者外周血中分泌IL-17的Th17细胞占CD4+T淋巴细胞百分比明显升高(P<0.01),CD4+CD25+Foxp3+Treg细胞占CD4+T淋巴细胞百分比明显降低(P<0.01);与正常未孕组相比,正常妊娠组Th17细胞的比例明显降低(P<0.01),Treg细胞比例明显升高(P<0.05);(2)子痫前期患者外周血中Th17/Treg比率明显高于正常未孕组及正常妊娠组(P<0.01),正常妊娠组外周血中Th17/Treg比率与健康未孕组相比明显降低(P<0.01);(3)子痫前期患者外周血中IL-17及TGF-β1的TGF-β1表达明显高于正常未孕组及正常妊娠组(P<0.05),而IL-10的表达未见明显差异(P>0.05);与正常未孕组相比,正常妊娠组外周血中IL-17、IL-10及TGF-β1的水平均未见明显变化(P>0.05)。结论:正常妊娠可能依赖于Treg细胞介导的免疫耐受状态,子痫前期患者外周血中Th17/Treg之间的平衡失调而倾向于Th17介导的促炎状态,这一机制可能参与了子痫前期的发生发展。     

The balance between cytotoxic NK cells and regulatory NK cells in human pregnancy

NK cells kill tumor cells and virus-infected cells as well as secrete a variety of cytokines. These effector functions are regulated by the balance between activating receptor signals and inhibitory receptor signals which are triggered by specific major histocompatibility complex (MHC) or non-MHC ligands. It is thought currently that the balance between immunostimulation and immunoregulation in T cell immunity is achieved by a Th1/Th2/Th3/Tr1 and CD4(+)CD25(+) regulatory T (Treg) cell paradigm. Here, we discuss the cytokine paradigm of NK cells in human pregnancy. During normal, intact pregnancy, peripheral blood NKr1 cells and decidual NK3 cells increase, while these NK cell populations decrease significantly in miscarriage cases, suggesting that an imbalance in NK1/NK2/NK3/NKr1 is correlated with miscarriage. Recent investigations have shown that not only Treg cells, but also regulatory NK (NK reg) cells, play very important roles in the maintenance of pregnancy. We summarize the progress in studying NK reg cells and focus on how NK reg cells and cytotoxic NK cells affect the reproductive immune response.     

Pregnancy-associated changes in peripheral blood lymphocyte subpopulations in normal Kuwaiti women.

It has recently been reported that healthy pregnancy is associated with systemic immunosuppression. The aim of this study was to evaluate the numbers and distribution of lymphocyte subpopulations in normal, healthy pregnant Kuwaiti women. Thirty-four healthy normotensive women in the 3rd trimester of pregnancy were studied using flow cytometry to define lymphocyte subpopulations and were compared with 16 non-pregnant women. A decrease in the absolute numbers of lymphocytes was observed affecting T cells (CD3+, CD4+, CD8+), B cells (CD19+), and natural killer cells (CD16+/CD56+). When analyzed as a percentage of the total lymphocyte population, there was a significant decrease in B cells and an increase in CD4+ T cells. The T cell population revealed increased expression of CD25 on CD4+ and CD8+ cells, of HLA-DR on CD8+ cells, and of CD54 on CD4+ T cells. The reduced number of lymphocytes suggests that Kuwaiti females may be immunosuppressed in the 3rd trimester of pregnancy. The presence of activated CD4+ T cells could indicate the expression of a regulatory suppressor T cell population, as Treg cells are CD4+CD25+, and suppressor T cells are thought to be CD8+. Future work is required to explore the significance of these T cell populations in pregnancy.     

Decidual CD4+CD25+CD127dim/- regulatory T cells in patients with unexplained recurrent spontaneous miscarriage

Objectives

To investigate the frequency and function of CD4⁺CD25⁺CD127^dim/− regulatory T (Treg) cells in decidua of patients with unexplained recurrent spontaneous miscarriage (URSM).

Study design

The decidual lymphocytes from patients who experienced URSM and normal pregnant women (controls) were collected by Ficoll density gradient centrifugation. CD4⁺CD25⁺CD127^dim/− Treg cells were isolated by magnetic cell sorting. The proportion of Treg cells and IL-10, TGF-β in Treg cells were determined by flow cytometry. Inhibitory effects of Treg cells on effecter T cells were detected with or without the presentation of anti-IL-10 antibodies and anti-TGF-β antibodies.

Results

The frequency of CD4⁺CD25⁺CD127^dim/− Treg cells was decreased in URSM decidua compared to controls (2.09% ± 0.86% vs. 2.97% ± 1.19%, p = 0.005), and the expression of IL-10 and TGF-β in Treg cells was lower in the URSM group than in the control group (p = 0.04 and p = 0.01, respectively). Furthermore, the suppressive effect of CD4⁺CD25⁺CD127^dim/− Treg cells on the proliferation of effector T cells was decreased in URSM decidua (p < 0.05). Suppression was mediated predominantly through IL-10 and TGF-β in decidua.

Conclusions

Decreased frequency and immunosuppressive capacity of CD4⁺CD25⁺CD127^dim/− Treg cells was found in URSM decidua. Treg cells inhibit proliferation of effector T cells mainly via IL-10 and TGF-β in URSM decidua.