不同树突状细胞对CD4~+CD25~+Foxp3~+调节性T细胞体外扩增的影响

目的利用不同种类树突状细胞(dendritic cells,DC)体外扩增获得表型和功能稳定的CD4+CD25+Foxp3+调节性T细胞(Treg)。方法免疫磁珠法(MACS)分离Balb/c小鼠CD4+CD25+调节性T细胞,利用与调节性T细胞同基因或异基因成熟DC、未成熟DC和调节性DC刺激其扩增,流式细胞术测定其纯度和表型。以CD4+CD25-T细胞作为反应细胞,验证扩增前后Treg细胞的免疫抑制功能。结果MACS分离的CD4+CD25+调节性T细胞纯度达到(95.38±1.82)%,同基因和异基因DC都能有效刺激Treg细胞体外扩增,其中同基因成熟DC扩增效果最为明显。而且同基因成熟DC扩增后CD4+CD25+调节性T细胞纯度达到(94.16±1.88)%,而且高表达Foxp3分子。当CD4+CD25+调节性T细胞与效应T细胞比例为1∶1时,能够有效的抑制效应T细胞的增殖,而且,同基因成熟DC扩增的CD4+CD25+调节性T细胞的抑制效果比新分离的Treg效果更好。结论同基因成熟DC能够体外扩增表型和功能稳定的Treg细胞。     

反复喘息幼儿外周血CD4+CD25+Foxp3+调节性T淋巴细胞、IL-10及IgE水平的研究

目的 研究CD4⁺CD25⁺叉头样转录因子3阳性（Foxp3⁺）调节性T淋巴细胞（Treg）及相关细胞因子、总IgE（TIgE）、特异性IgE（sIgE）在有或无特应征反复喘息幼儿外周血介导的免疫应答差异,为幼儿喘息性疾病的发展预测及治疗提供新思路。方法 选择反复喘息幼儿45例,分为特应征组22例和非特应征组23例,另选20名健康幼儿作为健康对照组,分别检测3组幼儿外周静脉血Treg计数和血清IL-10、IL-4、IL-5、IL-13、IFN-γ、TGF-β及TIgE、sIgE水平。结果 特应征组吸入及食入变应原sIgE阳性率高于非特应征组（P均<0.05）。特应征组外周血Treg计数和血清IL-10、IFN-γ水平低于非特应征组,而非特应征组低于对照组（P均<0.05）;特应征组血清IL-4、IL-5、IL-13、TIgE水平高于非特应征组,而非特应征组高于对照组（P均<0.05）。特应征组及非特应征组血清TGF-β水平比较差异无统计学意义（P>0.05）,均高于对照组（P均<0.05）。反复喘息患儿外周血Treg计数与血清IL-10水平呈正相关（r=0.875,P<0.001）。结论 Treg、IL-10、IL-4、IL-5、IL-13、TGF-β及IFN-γ可能参与了幼儿喘息,在过敏性疾病中发挥免疫调节作用。反复喘息幼儿外周血Treg计数与血清IL-10水平呈正相关。Treg与IL-10未来可能作为幼儿反复喘息早期预测及治疗的新靶点。     

TGF-beta1 maintains suppressor function and Foxp3 expression in CD4+CD25+ regulatory T cells

Transforming growth factor (TGF)-beta1 is a major pluripotential cytokine with a pronounced immunosuppressive effect and its deficiency results in lethal autoimmunity in mice. However, mechanisms of its immunosuppressive action are not completely understood. Here, we report that TGF-beta1 supports the maintenance of Foxp3 expression, regulatory function, and homeostasis in peripheral CD4(+)CD25(+) regulatory T (T reg) cells, but is not required for their thymic development. We found that in 8-10-d-old TGF-beta1-deficient mice, peripheral, but not thymic, T reg cells are significantly reduced in numbers. Moreover, our experiments suggest that a defect in TGF-beta-mediated signaling in T reg cells is associated with a decrease in Foxp3 expression and suppressor activity. Thus, our results establish an essential link between TGF-beta1 signaling in peripheral T reg cells and T reg cell maintenance in vivo.     

中国HIV早期感染者CD+4CD+25Foxp3+调节性T淋巴细胞变化研究

目的 研究1年以内感染HIV的感染者(早期感染者,EHI)体内CD+4 CD+25 Foxp3+调节性T淋巴细胞水平及其与疾病进展相关性.方法 随机选取51例HIV感染者,依据感染时间及CD+4 T淋巴细胞水平分为3组:EHI组30例、HIV组15例、AIDS组6例,20名健康人作为对照组,各组对象的年龄、性别具有可比性.用EDTA抗凝管采集全血,应用FACSAria流式细胞仪及Foxp3染色试剂盒,检测外周血单个核细胞CD+4CD+25Foxp3+调节性T淋巴细胞表达水平,分析EHI者及全部HIV感染者CD+4 CD+25Foxp3+调节性T淋巴细胞表达水平与CD+4T淋巴细胞数量、病毒调定点、病毒载量及淋巴细胞活化水平间的相关性.结果 健康对照组、EHI组、HIV组及AIDS组CD+4C+25Foxp3+T淋巴细胞百分率逐级上升,其中EHI组CD+4CD+25Foxp3+T淋巴细胞百分率[3.79(2.11～5.43)%]低于AIDS组[8.09(4.90～8.90)%],差异有统计学意义(Z=-2.29,P=0.022);EHI组CD+4 CD+25Foxp3+T淋巴细胞百分率与病毒调定点正相关(r=0.479,P=0.038),与CD4T淋巴细胞计数呈负相关(r=-0.455,P=0.011),与CD+3 HLA+T淋巴细胞呈正相关(r=0.533,P=0.002).结论 中国EHI者CD+4 CD+25Foxp3+调节性T淋巴细胞百分率高与高病毒调定点及低CD+4 T淋巴细胞数量相关,提示CD+4 CD+25Fox3+调节性T淋巴细胞是加速HIV感染早期疾病进展的因素之一.     

CD4+CD25+Foxp3+调节性T细胞在CIK细胞诱导中的表达及其功能

目的探讨肿瘤患者自体细胞因子诱导的杀伤细胞(CIK)诱导过程中CD4~+CD25~+Foxp3~+调节性T细胞的变化及其功能。方法应用血细胞分离机采集22例肿瘤患者外周血单个核细胞(PBMC),诱导培养CIK细胞,用流式细胞仪动态监测其CD4~+CD25~+Foxp3~+表型,并分析Tregs细胞负性调控分子转化生长因子-β1(TGF-β1)、细胞毒性T淋巴细胞相关抗原4(CTLA-4)和IL-10的表达水平,采用细胞增殖抑制试验测定Tregs细胞免疫学功能。结果诱导的CIK细胞中存在CD4~+CD25~+Foxp3~+Tregs,其表达量分别为第1天(0.30±0.15)%、第3天(4.48±1.72)%、第5天(3.83±2.12)%、第9天(2.37±1.17)%、第11天(1.65±0.99)%、第14天(1.04±0.76)%。诱导第14天时的Tregs细胞免疫调控负性分子TGF-β1的表达水平为(97.2±2.1)%、CTLA-4为(96.2±3.5)%、IL-10为(4.2±2.3)%。细胞增殖抑制试验中空白对照组、条件对照组以及实验组的增殖细胞表达量分别为(8.55±2.38)%、(42.66±7.32)%、(57.04±7.49)%。结论 CD4~+CD25~+Foxp3~+Tregs细胞可作为潜在的CIK细胞质量评价指标。     

甘草酸二铵对慢性乙型肝炎患者外周血CD4＋CD25＋Foxp3＋调节性T细胞的影响

目的探讨应用甘草酸二铵后,慢性乙型肝炎（CHB）患者外周血CD4＋CD25＋Foxp3＋调节性T细胞（Treg）的变化情况。方法选取CHB患者60例（CHB组）,甘草酸二铵治疗30d并采集治疗开始前、开始后15d、治疗结束后第2天的外周血,同时选择60例乙肝表面抗原阴性的健康体检者作为对照组。采用三色荧光标记流式细胞术检测两组外周血中CD4^＋CD25^＋Foxp3^＋Treg的含量。结果CHB组在治疗开始前外周血Treg高于对照组（P〈0．05）;治疗15d后,外周血Treg含量较治疗开始前下降,但仍高于对照组（P均〈0．05）;治疗30d后Treg含量进一步下降,与前两次相比,差异均具有统计学意义,且仍高于对照组（P均〈0．05）。结论外周血Treg可能参与CHB患者乙型肝炎病毒（HBV）免疫耐受。甘草酸二铵可降低患者外周血Treg数量,提示其可能通过对HBV的免疫调节实现其治疗作用。     

CD4(+)CD25(-)Foxp3(-) Th1 cells are the source of IL-10-mediated immune suppression in chronic cutaneous leishmaniasis

Nonhealing forms of leishmaniasis in humans are commonly associated with elevated levels of the deactivating cytokine IL-10, and in the mouse, normally chronic infections can be cleared in the absence of IL-10. Using a Leishmania major strain that produces nonhealing dermal lesions in a T helper type 1 (Th1) cell-polarized setting, we have analyzed the cellular sources of IL-10 and their relative contribution to immune suppression. IL-10 was produced by innate cells, as well as CD4(+)CD25(+)Foxp3(+) and CD4(+)CD25(-)Foxp3(-) T cells in the chronic lesion. Nonetheless, only IL-10 production by antigen-specific CD4(+)CD25(-)Foxp3(-) T cells, the majority of which also produced IFN-gamma, was necessary for suppression of acquired immunity in Rag(-/-) reconstituted mice. Surprisingly, Rag(-/-) mice reconstituted with naive CD4(+) T cells depleted of natural T regulatory cells developed more severe infections, associated with elevated levels of IL-10 and, especially, Th2 cytokines in the site. The data demonstrate that IL-10-producing Th1 cells, activated early in a strong inflammatory setting as a mechanism of feedback control, are the principal mediators of T cell-derived IL-10-dependent immune suppression in a chronic intracellular infection.     

胃癌CD4~+CD25~+Foxp3~+调节性T细胞的异常增高与患者免疫抑制状态的相关性分析

目的:探讨CD4+CD25+Foxp3+调节性T(Treg)细胞在胃癌患者血清及腹腔冲洗液(或积液)中异常增高与机体免疫状态的关系。方法:采用酶联免疫吸附试验(ELISA)检测胃癌患者血清和腹腔冲洗液中IFN-γ、IL-4细胞因子的水平。利用多参数流式细胞仪分析56例胃癌患者术前的外周血和肿瘤组织浸润淋巴细胞(TIL)中Treg细胞及CD8+T细胞[又称细胞毒T淋巴细胞(CTL)]的比率。另检测12例胃癌患者手术前后外周血Treg细胞的比率变化。结果:相对于健康对照组,胃癌患者血清Th1/Th2比例降低,差异有统计学意义(P<0.05)。胃癌患者外周血中的Treg细胞比率明显高于健康对照组,晚期患者高于早期患者,差异有统计学意义(P均<0.05);TIL中Treg比率明显高于外周血(P<0.05)。12例患者肿瘤切除后Treg细胞比率明显降低,差异具有统计学意义(P<0.01)。结论:胃癌患者血清及肿瘤组织中Treg细胞的比率随肿瘤进展而升高;Treg细胞比率升高和CTL降低可能参与肿瘤细胞的免疫逃逸。     

自身免疫性甲状腺炎大鼠CD4^＋CD25^＋调节性T细胞变化及意义

目的研究CD4^＋CD25^＋Foxp3^＋调节性T细胞在自身免疫性甲状腺炎（AITD）大鼠外周血中的比例变化,并初步探讨其在疾病进程中的意义。方法选取17例A1TD大鼠,取静脉血,应用流式细胞术及定量PCR的方法,分别在蛋白质和mRNA水平检测Foxp3^＋表达,并与甲状腺炎球蛋白抗体（TgAb）,甲状腺过氧化酶抗体（TPOAb）,甲状腺微粒体抗体（TmAb）和甲状腺组织活检结果作相关分析。取正常大鼠作为对照。结果AITD大鼠CD4^＋CD25^＋调节性T细胞（5．35％±1．27％）显著低于正常对照组（8．02％±2．29％,P〈0．01）,AITD大鼠CD4^＋CD25^＋Foxp3^＋T细胞占CD4‘T细胞比例（3．12％±0．78％）明显低于正常对照组（6．45％±2．12％,P〈0．01）,AITD大鼠Treg与TgAb、TmAb、TPOAb呈负相关（r=-0．291,-0．357,-0．389,P〈0．05,0．05,0．05）,并与小鼠甲状腺组织的炎症程度呈负相关（r=-0．511,P〈0．01）;Foxp3mRNA表达水平与蛋白质表达水平变化相一致。结论AITD大鼠CD4^＋CD25^＋T细胞明显减少,这群调节性T细胞可能参与了AITD的病理进程。     

Human CD4+ CD25hi Foxp3+ regulatory T cells are derived by rapid turnover of memory populations in vivo

While memory T cells are maintained by continuous turnover, it is not clear how human regulatory CD4+ CD45RO+ CD25hi Foxp3+ T lymphocyte populations persist throughout life. We therefore used deuterium labeling of cycling cells in vivo to determine whether these cells could be replenished by proliferation. We found that CD4+ CD45RO+ Foxp3+ CD25hi T lymphocytes were highly proliferative, with a doubling time of 8 days, compared with memory CD4+ CD45RO+ Foxp3- CD25- (24 days) or naive CD4+ CD45RA+ Foxp3- CD25- populations (199 days). However, the regulatory population was susceptible to apoptosis and had critically short telomeres and low telomerase activity. It was therefore unlikely to be self regenerating. These data are consistent with continuous production from another population source. We found extremely close TCR clonal homology between regulatory and memory CD4+ T cells. Furthermore, antigen-related expansions within certain TCR Vbeta families were associated with parallel numerical increases of CD4+ CD45RO+ CD25hi Foxp3+ Tregs with the same Vbeta usage. It is therefore unlikely that all human CD4+ CD25+ Foxp3+ Tregs are generated as a separate functional lineage in the thymus. Instead, our data suggest that a proportion of this regulatory population is generated from rapidly dividing, highly differentiated memory CD4+ T cells; this has considerable implications for the therapeutic manipulation of these cells in vivo.     

同种异基因抗原特异性调节性T细胞的体外扩增

目的建立用人B淋巴细胞体外获得大量的同种异基因抗原特异性调节性T(Treg)细胞的方法,以此检测扩增细胞的表型及其免疫无能性和免疫抑制性。方法第1轮扩增将免疫磁珠分选的人CD4+CD25+T细胞和人B淋巴细胞按1∶4体外混合培养,并加入外源白介素-2(IL-2)和抗-CD28;将第1轮扩增得到的Treg细胞用抗-CD3/CD28包被的免疫磁珠和IL-2刺激,做第2轮扩增以获得更多数量的抗原特异性Treg细胞,分为添加和或未添加免疫抑制剂雷帕霉素(RAPA)2组(n=3)。结果经过2轮的扩增后,在第2轮扩增中未添加RAPA组扩增1×103倍,纯度80%;添加RAPA组扩增0.8×103倍,纯度90%。添加RAPA组得到的Treg细胞的Foxp3、CT-LA4、CD39表达水平高于未添加RAPA组,但是HLA-DR变化不大;未添加RAPA组扩增得到的Treg细胞分泌低水平的IL-2、IL-17、IL-4和IFN-γ,而添加RAPA组得到的Treg细胞几乎不分泌上述各种细胞因子,前者表现出部分免疫反应无能性,后者表现出完全的免疫反应无能性,两者都表现出免疫抑制性功能特征。人B淋巴细胞扩增得到的抗原特异性Treg细胞能够极大地抑制同源抗原引起的免疫反应,而对多克隆刺激的免疫反应抑制能力较弱。结论用人B细胞体外扩增抗原特异性Treg细胞,再通过抗-CD3/CD28包被的免疫磁珠进一步刺激可以体外获得大量的抗原特异性的Treg细胞,加入RAPA后可有效地提高Treg细胞的纯度和免疫抑制力且呈现抗原特异性。     

In vivo equilibrium of proinflammatory IL-17+ and regulatory IL-10+ Foxp3+ RORgamma t+ T cells

The nuclear hormone receptor retinoic acid receptor-related orphan receptor gamma t (RORgamma t) is required for the generation of T helper 17 cells expressing the proinflammatory cytokine interleukin (IL)-17. In vivo, however, less than half of RORgamma t(+) T cells express IL-17. We report here that RORgamma t(+) T alphabeta cells include Foxp3(+) cells that coexist with IL-17-producing RORgamma t(+) T alphabeta cells in all tissues examined. The Foxp3(+) RORgamma t(+) T alphabeta express IL-10 and CCL20, and function as regulatory T cells. Furthermore, the ratio of Foxp3(+) to IL-17-producing RORgamma t(+) T alphabeta cells remains remarkably constant in mice enduring infection and inflammation. This equilibrium is tuned in favor of IL-10 production by Foxp3 and CCL20, and in favor of IL-17 production by IL-6 and IL-23. In the lung and skin, the largest population of RORgamma t(+) T cells express the gammadelta T cell receptor and produce the highest levels of IL-17 independently of IL-6. Thus, potentially antagonistic proinflammatory IL-17-producing and regulatory Foxp3(+) RORgamma t(+) T cells coexist and are tightly controlled, suggesting that a perturbed equilibrium in RORgamma t(+) T cells might lead to decreased immunoreactivity or, in contrast, to pathological inflammation.     

HCV早期感染者病毒载量与CD4~+CD25~+Foxp3~+调节性T淋巴细胞相关性研究

目的研究丙型肝炎病毒(HCV)早期感染者(抗原阳性、抗体阴性)的HCV病毒载量与CD4+CD25+叉头/翅膀状螺旋转录因子(Foxp3+)调节性T淋巴细胞水平的相关性,分析CD4+CD25+Foxp3+调节性T淋巴细胞在HCV感染中的作用。方法应用实时荧光定量聚合酶链反应(FQ RT-PCR)技术检测22例HCV核心抗原阳性、抗体阴性(即HCV Ag阳性、抗-HCV阴性)的早期感染病例、26例核心抗原阳性、抗体阳性(即HCV Ag阳性、抗-HCV阳性)的慢性HCV感染病例,24例核心抗原阴性、抗体阳性(即HCV Ag阴性、抗-HCV阳性)的既往HCV感染病例及22例健康对照组HCV RNA病毒载量;并用流式细胞技术检测各组外周血有核细胞中的CD4+CD25+Foxp3+调节性T淋巴细胞水平。结果 HCV Ag阳性、抗-HCV阴性组,HCV Ag阳性、抗-HCV阳性组,HCV Ag阴性、抗-HCV阳性组及健康对照组CD4+CD25+Foxp3+调节性T淋巴细胞逐级下降,其中抗原阳性、抗体阴性组[(4.86±2.14)%]高于其他组[分别为(3.74±1.67)%、(2.74±1.27)%、(2.56±1.18)%],差异有统计学意义(t值分别为2.023、4.125、4.402,P0.05);HCV Ag阳性、抗-HCV阴性组CD4+CD25+Foxp3+调节性T淋巴细胞与HCV RNA病毒载量的对数(copy/mL,Ig)呈正相关(r=0.535,P0.05)。结论 HCV早期感染者CD4+CD25+Foxp3+调节性T淋巴细胞水平与高病毒调定点相关,CD4+CD25+Foxp3+调节性T淋巴细胞水平可能是加速HCV早期感染的影响因素之一。     

CD4^＋CD25^＋调节性T细胞与自身免疫病

目的:CD4 CD25 调节性T细胞是一群具有免疫调节或免疫抑制功能的细胞。越来越多的实验证明,CD4 CD25 调节性T细胞在维持外周免疫耐受中起重要作用,这种T细胞的数量减少或功能缺失可导致自身免疫性疾病的发生。本文就CD4 CD25 调节性T细胞及其在自身免疫性疾病中作用的研究进展做一综述。资料来源:应用计算机检索CNKI、Medline、EMCC数据库和手工检索2006-2007年的相关文献。检索词为"CD4 CD25 T调节性细胞,自身免疫病,免疫耐受,CD4 CD25 regulatory T cell,Treg,autoimmune disease,immune tolerance"。资料选择:检索范围包括临床研究(不限研究对象的年龄、性别、种族)和基础研究,不限体内和体外研究。资料提炼:共收集到相关文献675篇,选择其中33篇英文文献进行重点阅读和分析。资料综合:CD4 CD25 调节性T细胞具有免疫抑制功能,在机体的免疫调节中发挥重要作用。与其免疫调节功能相关的杀伤性T细胞淋巴细胞相关抗原4、CD45RO、糖皮质激素诱导的肿瘤坏死因子受体、淋巴细胞的无能相关基因等细胞表面分子和白细胞介素2、白细胞介素10、白细胞介素4、转化生长因子β等细胞因子的研究不断深入。此外,CD4 CD25 调节性T细胞功能的发挥还与FOXP3的表达密切相关。CD4 CD25 调节性T细胞数量的减少、抑制功能的受损和(或)细胞表面分子表达的缺陷可能导致1型糖尿病、多发性硬化和炎症性肠病等多种自身免疫病的发生。结论:CD4 CD25 调节性T细胞主要通过细胞接触依赖机制和抑制性细胞因子依赖机制发挥免疫抑制效应。其数量的减少、功能的受损和(或)表面分子表达的缺陷与自身免疫病的发生发展密切相关。     

CD_4~+ CD_(25)~+ Foxp3~+调节性T淋巴细胞与Graves病复发的关系

Treg为一群具有免疫抑制效应的T淋巴细胞亚群,在维持机体自身耐受和抑制自身免疫性疾病发生发展中具有重要作用.     

半乳凝素-10在CD4^＋CD25^＋CD127^low／-调节性T细胞中的表达与意义

目的探讨半乳凝素-10(galectin-10)在CD4 CD25 CD127low/-调节性T细胞(regulatory T cell,Treg)中的表达及其与Foxp3的相关性。方法通过流式细胞术分选健康人外周血和胃癌患者癌旁淋巴结中Treg细胞与CD4 CD25-CD127 T细胞,经微量抽提RNA后,用RT-PCR检测galectin-10和Foxp3的mRNA表达水平。结果galectin-10和Foxp3的mRNA显著表达于Treg细胞,几乎不表达于CD4 CD25-CD127 T细胞。健康人外周血和胃癌患者癌旁淋巴结中的结果一致。结论ga-lectin-10基因高表达于Treg细胞中,可以作为Treg细胞一项新的标志物。     

脓毒症患者自然调节性T细胞及可溶性CD25水平研究

目的 通过前瞻性研究探讨脓毒症患者外周血自然调节性T细胞(Treg)百分比和血浆可溶性CD25分子(IL-2sRa)水平的变化及其临床价值.方法 将2009年2月至2010年2月上海交通大学附属瑞金医院重症医学科所收治的符合ACCP/SCCM于1997年提出的SIRS与脓毒症诊断标准的37例脓毒症患者与15例非感染SIRS患者,以及上海交通大学附属瑞金医院体检中心24例排除感染及免疫系统基础疾病患者,根据诊断标准分为脓毒症组、非感染SIRS组与正常对照组.其中脓毒症组男性26例,女性11例,年龄(61.67±11.87)岁;非感染SIRS组男性8例,女性7例,年龄(67.06±12.57)岁;正常对照组男14例,女10例,年龄(56.54±6.37)岁.脓毒症组肺部感染28例,腹腔感染6例,其他4例;非感染SIRS组为择期清洁手术后24 h内无感染征象者.所有入选对象均排除免疫系统基础疾病和(或)近期(30 d内)曾使用或正在使用强效免疫抑制剂患者.流式细胞分析术检测三组外周血Treg细胞百分比,ELISA检测血浆IL-2sRa,IL-4,IFN-γ水平.所得数据采用方差分析及非参数检验的Kruskal-Wallis H方法.结果 ①Treg细胞在脓毒症组、SIRS组和正常对照组占外周血CD4+CD25+T细胞的比例分别为:(66.82±21.79)%,(51.79±21.79)%、(56.45±10.68)%,脓毒症组Treg细胞显著高于SIRS组和正常对照组(P=0.001).②与SIRS组(381.664±189.83)和对照组(164.132±56.37)相比,脓毒症组可溶性CD25分子(IL-2sRa)水平(425.619±270.12)显著增高(P=0.000).③IL-2sRa浓度与Treg细胞占CD4+CD25+T细胞的比例相关分析示:Spearman相关系数=0.390,P=0.003(P＜0.05),两者存在正相关关系.结论 Treg细胞在脓毒症患者外周血的表达水平特征性增高.而外周血IL-2sRa水平可以反映Treg细胞表达水平,也有助于简化判断脓毒症的免疫状态的方法.

Abstract：

Objective To explore the CD4 + CD25 + Foxp3 + regulatory T cell percentage and plasma levels of soluble CD25 molecules in peripheral blood of septic patients and their clinical value through prospective study. Method A total of 37 septic patients and 15 non-infectious SIRS patients, who conformed to the criteria of SIRS and sepsis which proposed by American College of Chest Physicians/Society of Critical Care Medicine Consensus Conference ( ACCP/SCCM ) in 1997, were collected in ICU of Ruijin Hospital ( Shanghai Jiaotong University) from February 2009 to February 2010. Twenty-four health people were from Medical Center of Ruijin Hospital, who were excluded infection and (or) autoimmune diseases. There were 26 male and 11 female in sepsis group, average age ( 61.67 ± 11.87 ) years old; 8 male and 7 female in SIRS group, average age (67.06 ± 12.57)years old; 14 male and 10 female in health control, average age (56.54 ± 6.37 )years old. All selected patrents were excluded the autoimmune diseases and (or) patients within recent (30 days) had used or now used immunosuppressive agents. We therefore measured the Treg cell percentage in peripheral blood by Flow Cytometry and the plasma levels of IL-2sRa, IL-4, IFN-γ by ELISA. The data were analyzed by analysis of variance or nonparametric Kruskal-Wallis H test. Results ① The percentage of CD4 + CD25 + Foxp3 + regulatory T cells among septic patients, SIRS patients, and control group was: ( 66.82 ± 21.79 ) %, ( 51.79 ± 21.79 ) %, ( 56.45 ± 10. 68 ) %, respectively. septic patients showed the highest percentages of CD4 + CD25 + Foxp3 + regulatory T cell among CD4 + CD25 + T cells(P ＜ 0.05 ). ② The plasma levels of soluble CD25 in septic patients (425. 619 ± 270.12 ) were significantly higher than SIRS patients (381. 664 ± 189.83) and the control group ( 164. 1 32 ± 56.37 ) ( P ＜ 0.05 ). ③ The correlation analysis between the concentration of soluble CD25 molecules in plasma and the ratio of CD4 + CD25 + Foxp3 + regulatory T cells to CD4 + CD25 + T cells showed Spearman correlation coefficient =0.390, P = 0.003 ( P ＜ 0.05 ). Conclusion: the expression of natural regulatory T cells characteristically increased in septic patients. And the levels of soluble CD25 in peripheral blood were related to the percentages of natural regulatory T cells, which simplified the assessment of the immune status in Septic patients.