CD4~+ CD25~+调节性T细胞及其在肿瘤免疫治疗中的意义

CD4+CD25+调节性T细胞是具有独特免疫调节功能的T细胞亚群。近年来研究发现各种恶性肿瘤患者外周血及肿瘤环境中该细胞比例增加,去除CD4+CD25+调节性T细胞或封闭其抑制功能可以增强抗肿瘤免疫反应。CD4+CD25+调节性T细胞成为肿瘤免疫治疗的新靶点。     

Vascular endothelial growth factor blockade reduces intratumoral regulatory T cells and enhances the efficacy of a GM-CSF-secreting cancer immunotherapy.

PURPOSE: The purpose of the present study was to evaluate granulocyte macrophage colony-stimulating factor (GM-CSF)-secreting tumor cell immunotherapy in combination with vascular endothelial growth factor (VEGF) blockage in preclinical models. EXPERIMENTAL DESIGN: Survival and immune response were monitored in the B16 melanoma and the CT26 colon carcinoma models. VEGF blockade was achieved by using a recombinant adeno-associated virus vector expressing a soluble VEGF receptor consisting of selected domains of the VEGF receptors 1 and 2 (termed sVEGFR1/R2). Dendritic cell and tumor infiltrating lymphocyte activation status and numbers were evaluated by fluorescence-activated cell sorting analysis. Regulatory T cells were quantified by their CD4+CD25hi and CD4+FoxP3+ phenotype. RESULTS: The present study established that GM-CSF-secreting tumor cell immunotherapy with VEGF blockade significantly prolonged the survival of tumor-bearing mice. Enhanced anti-tumor protection correlated with an increased number of activated CD4+ and CD8+ tumor-infiltrating T cells and a pronounced decrease in the number of suppressive regulatory T cells residing in the tumor. Conversely, overexpression of VEGF from tumors resulted in elevated numbers of regulatory T cells in the tumor, suggesting a novel mechanism of VEGF-mediated immune suppression at the tumor site. CONCLUSION: GM-CSF-secreting cancer immunotherapy and VEGF blockade increases the i.t. ratio of effector to regulatory T cells to provide enhanced antitumor responses. This therapeutic combination may prove to be an effective strategy for the treatment of patients with cancer.     

FOXP3+ regulatory T cells affect the development and progression of hepatocarcinogenesis.

PURPOSE: Tumor-infiltrating lymphocytes represent the host immune response to cancer. CD4+CD25+FOXP3+ regulatory T cells (Tregs) suppress the immune reaction. The aim of the present study was to investigate the clinicopathologic significance and roles of Tregs and CD8+ T cells during hepatocarcinogenesis. EXPERIMENTAL DESIGN: We examined the infiltration of FOXP3+ Tregs and CD8+ T cells in the tumor stroma and nontumorous liver parenchyma using 323 hepatic nodules including precursor lesions, early hepatocellular carcinoma (HCC), and advanced HCC, along with 39 intrahepatic cholangiocarcinomas and 59 metastatic liver adenocarcinomas. We did immunohistochemical comparative studies. RESULTS: The prevalence of Tregs was significantly higher in HCC than in the nontumorous liver (P<0.001). The patient group with a high prevalence of Tregs infiltrating HCC showed a significantly lower survival rate (P=0.007). Multivariate analysis revealed that the prevalence of Tregs infiltrating HCC was an independent prognostic factor. The prevalence of Tregs increased in a stepwise manner (P<0.001) and that of CD8+ T cells decreased during the progression of hepatocarcinogenesis (P<0.001). Regardless of the presence of hepatitis virus infection or histopathologic evidence of hepatitis, the prevalence of Tregs was significantly increased in nontumorous liver bearing primary hepatic tumors. CONCLUSIONS: Tregs play a role in controlling the immune response to HCC during the progression of hepatocarcinogenesis. It has been suggested that primary hepatic cancers develop in liver that is immunosuppressed by a marked infiltration of Tregs. A high prevalence of Tregs infiltrating HCC is thought to be an unfavorable prognostic indicator.     

The Putative Role of Natural Killer Cells in Patients with Hepatitis C Virus-Related Hepatocellular Carcinoma

Background: Natural Killer (NK) cells have crucial roles in immune responses against malignant transformation including hepatocellular carcinoma (HCC). The NKG2D receptor has a critical role in the NK recognition of target cells. Aim: We assessed NKG2D receptor expression as a diagnostic biomarker for HCC detection and progression in Egyptian patients with hepatitis C virus (HCV)-related HCC. Methods: We classified 81 patients into three groups: chronic hepatitis (21), cirrhotic (30) and HCC (30) patients, with 36 individuals enrolled to the control group. We analyzed NK levels in peripheral blood and NKG2D receptor expression in NK cells using flow cytometry. Results: We observed a significant decrease in NKG2D (CD314) expression on circulating NK cells and frequency of NK cells expressing NKG2D (CD314) in HCC patients. Also, in patients, larger foci lesions significantly correlated with decreased NK cell numbers. Multiple foci numbers and patients with a Child score C significantly correlated with decreased circulating NK cells expressing NKG2D and decreased NKG2D expression. Conclusion: The percentage of NK cells in peripheral blood and NKG2D receptor expression could function as potential biomarkers for HCC detection and progression.     

Tumour-associated macrophages are related to progression in patients with metastatic melanoma following interleukin-2 based immunotherapy

The aim of the present study was to analyze whether leukocyte subsets in peripheral blood and tumour biopsies obtained before treatment were able to predict response or survival in patients with metastatic melanoma following Interleukin-2 (IL-2) based immunotherapy. Flow cytometry was performed on peripheral blood for CD4+ T cells, CD8+ T cells and CD56+ natural killer (NK) cells. Immunohistochemical analyses were used to identify CD4+ T cells, CD8+ T cells, CD57+ NK cells and CD64+ (macrophages) cells in tumour biopsies. High numbers of tumour-associated CD64+ macrophages in tumour biopsies were statistically significantly associated with poor response to treatment. Our data suggest that tumour-associated macrophages may correlate negatively with response, which may be of biological importance for IL-2 based immunotherapy of malignant melanoma.     

原发性肝癌患者CD4+CD25+CD127low调节性T细胞的检测及意义

探讨CD4+CD25+CD127low调节性T细胞（Tregs）在原发性肝细胞性肝癌（HCC）患者外周血中的变化及其临床意义。方法:采集40例乙型肝炎病毒（HBV）相关的HCC患者［巴塞罗那临床肝癌（BCLC）分期A期患者7例、B期患者8例、C期患者20例、D期患者5例］、35例慢性乙型肝炎（CHB）患者及28例正常健康人的外周抗凝血,应用CD4（PE-CY5）、CD25（FITC）、CD127（PE）三种特异性荧光抗体标记后,通过流式细胞术对CD4+CD25+CD127lowTregs水平进行三色荧光抗体检测。结果:HCC患者外周血CD4+CD25+CD127lowTregs占CD4+T细胞的百分比显著高于正常健康人（P<0.001）和CHB患者（P=0.017）,CHB患者外周血CD4+CD25+CD127lowTregs占CD4+T细胞的百分比高于正常健康人（P=0.035）;HCC中BCLC分期为C期的患者外周血CD4+CD25+CD127lowTregs占CD4+T细胞的百分比显著高于A期患者（P=0.020）和B期患者（P=0.019）。结论:CD4+CD25+CD127lowTregs水平异常增高可能是HCC免疫逃逸的一个重要机制,且其变化水平与临床病情的进展存在一定的相关性。      

Altered cytokine levels and increased CD4+CD57+ T cells in the peripheral blood of hepatitis C virus-related hepatocellular carcinoma patients

Although CD57+ lymphocytes are closely correlated with prognosis in various cancers, the role of subsets of CD57+ cells in hepatitis C virus (HCV)-related hepatocellular carcinoma (HCC) is unclear. In the present study, peripheral blood (PB) from HCV-related HCC patients was analyzed. Plasma cytokine levels and in vitro cytokine-producing capabilities were analyzed with enzyme-linked immunosorbent assays, and CD57+ cell subsets were studied using a multi-color FACS system. Interferon (IFN)-γ was undetectable in the plasma of patients with tumors at any stage, whereas the plasma levels of tumor necrosis factor (TNF)-α, interleukin (IL)-10 and IL-18, but not that of IL-12, were significantly higher in stage IV patients compared to patients with earlier-stage tumors. In contrast, the IFN-γ-producing capability of PB was highest in stage I patients and gradually decreased with tumor progression. The IL-10-, IL-18- and IL-12-producing capabilities of PB increased from stage I to III. However, PB-TNF-α, IL-10- and IL-18-producing capabilities were reduced in stage IV patients, probably due to repeated anti-cancer treatments. The percentage of CD4+CD57+αβTCR+ cells (CD4+CD57+ T cells) in peripheral blood lymphocytes (PBLs) increased with tumor progression. Moreover, the percentage of CD4+CD57+ T cells in PBLs and the ratio of CD4+CD57+ T cells to CD4+αβTCR+ cells (CD4+ T cells), but not that of CD4+CD57+ T cells to CD57+αβTCR+ cells (CD57+ T cells), showed a significant inverse correlation with PB-IFN-γ-producing capability. The present results suggest that an increase in CD4+CD57+ T cells controls the capability of PB to produce the anti-tumor cytokine IFN-γ and that PB-IFN-γ production is impaired with HCC tumor progression.     

Immune responses of dendritic cells combined with tumor-derived autophagosome vaccine on hepatocellular carcinoma

Background

To induce and collect tumor-derived autophagosomes (DRibbles) from tumor cells as an antitumor vaccine by inhibiting the functions of proteasomes and lysosomes.

Methods

Dendritic cells (DCs) generated from peripheral blood mononuclear cell (PBMC) of hepatocellular carcinoma (HCC) patients were cocultured with DRibbles, and then surface molecules of DCs, as well as surface molecules on DCs, were determined by flow cytometry. Meanwhile, immune responses of the DCs-DRibbles were examined by mixed lymphocyte reactions.

Results

DRibbles significantly induced the expression of CD80, CD83, CD86 and HLA-DR on DCs. The enzyme-linked immunosorbnent assay (ELISA) showed that IFN-γ levels after vaccination increased than before in most patients, but CD8+ proportion of PBMC increased only in nine patients. Higher levels of IFN-γ were detected in the CD8+ cells than CD4+ T cells. These results suggested that DCs-DRibbles vaccine could induce antigen-specific cellular immune response on HCC and could prime strong CD8+ T cell responses, supporting it as a tumor vaccine candidate.

Conclusions

Our results demonstrate that HCC/DRibbles-pulsed DCs immunotherapy might be deployed as an effective antitumor vaccine for HCC immunotherapy in clinical trials.     

Expression of Fas/FasL in CD8+ T and CD3+ Foxp3+ Treg Cells - Relationship with Apoptosis of Circulating CD8+ T Cells in Hepatocellular Carcinoma Patients

Aims: Dysfunction of the host immune system in cancer patients can be due to a number of factors, includinglymphocyte apoptosis. Several studies showed that Foxp3+T cells take part in inducing this process by expressingFasL in tumor patients. However, the relationship between apoptosis, CD8+T cells and Foxp3+T cells in HCCpatients is still unclear. The present study was designed to investigate the correlation between apoptosis levelsand Fas/FasL expression in CD8+T lymphocytes and Foxp3+T cells in patients with HCC. Methods: CD8+T cellsand CD3+Foxp3+T cells were tested from peripheral blood of HCC patients and normal controls and subjectedto multicolor flow cytometry. The expression of an apoptosis marker (annexin V) and the death receptor Fas inCD8+T cells and FasL in CD3+Foxp3+T cells were evaluated. Serum TGF-β1 levels in patients with HCC weremeasured by enzyme-linked immunosorbent assay. The relationship between apoptosis and Fas expression, aswell as FasL expression in CD3+Foxp3+T cells was then evaluated. Results: The frequency of CD8+T cells bindingannexin V and Fas expression in CD8+T cells, were all higher in HCC patients than normal controls and theproportion of apoptotic CD8+T cells correlated with their Fas expression. Serum TGF-β1 levels correlated inverselywith CD3+Foxp3+T cells. Conclusions: Fas/FasL interactions might lead to excessive turnover of CD8+T cellsand reduce anti-tumor immune responses in patients with HCC. Further investigations of apoptosis inductionin Fas+CD8+T cells in vitro are required.     

“癌症进化发育学”理论进展及其在肝细胞癌靶向/免疫治疗中的作用

原发性肝癌居我国癌症非成熟死亡原因的首位，其中肝细胞癌占93.0%，84.4%是乙肝病毒（HBV）慢性感染所致。在HBV致癌过程中，非可控性炎性反应通过IL-6上调胞苷脱氨酶AID/APOBEC3s家族成员以促病毒和宿主基因变异、下调尿嘧啶DNA糖基化酶（UNG）等降低变异修复，炎性微环境为HBV和人肝细胞的“变异-选择-适应”进化过程提供了必要条件并促进变异细胞逆向分化。该进化过程需满足体细胞驱动突变和免疫抑制微环境这两个前提条件。促癌基因组不稳定和HBV变异通过cGAS-STING抑制Ⅰ型干扰素信号，诱导免疫抑制性炎性反应，招募抑制性免疫细胞如TAMs、Treg、MDSC等构建肿瘤微环境。微环境中肿瘤细胞迅速生长所致的缺氧通过诱导免疫抑制性炎性反应因子激活肿瘤犬尿氨酸代谢，增强Treg的PD-1表达以加强免疫耐受、抑制CD8+T细胞和NK细胞毒性、促进新血管生成。以上“癌症进化发育学”理论为癌症的防治指明了方向。针对新血管生成的靶向治疗能显著遏制肝癌生长、提高抗肿瘤免疫，加强免疫治疗效果。靶向-免疫联合治疗应成为晚期肝癌的主要治疗措施。     

原发性肝癌患者外周血和癌组织中调节性T细胞数量及其临床意义

目的 探讨原发性肝癌患者外周血中调节性T细胞(Treg)占CD4+T细胞(Treg/CID4+)比值和肝癌组织中Treg数量及其临床意义.方法 63例原发性肝癌患者均行根治性手术切除,采用流式细胞术检测患者手术前外周血中Treg/CD4+比值,用免疫组织化学方法检测肿瘤组织中Treg的表达.结果 原发性肝癌患者外周血中Treg/CD4+比值显著高于乙型肝炎患者(P<0.01)及正常对照组(P<0.01).癌组织中Treg数量为(15.69±13.29)个/mm2,癌旁肝组织、10例乙型肝炎肝组织、10例正常肝组织中未见或极少见Treg.外周血中Treg/CD4+比值与癌组织中Treg数量呈正相关(P=0.024).外周血和癌组织中Treg数量高者,术后5年生存率低(P值分别为0.042、0.019);癌组织中Treg数量高者,术后5年无瘤生存率低(P=0.001).结论 原发性肝癌患者外周血和组织中调节性T细胞水平升高;外周血中Treg/CD4+比值及癌组织中Treg数量可作为预测患者根治术后预后的免疫学指标.     

Enhanced functionality of CD4+CD25(high)FoxP3+ regulatory T cells in the peripheral blood of patients with prostate cancer

PURPOSE: CD4+CD25(high)FoxP3+ regulatory T cells (Treg) have been shown to inhibit the activation and function of T cells that participate in antigen-specific immune responses. Higher levels of Tregs have been reported in the peripheral blood of patients with several types of tumors. In this study, we investigated the number and functionality of CD4+CD25(high)FoxP3+ Tregs in patients with prostate cancer (PCa), and their potential role in inhibiting antitumor immune responses. EXPERIMENTAL DESIGN: Levels of Tregs in the peripheral blood of healthy donors and patients with biochemically progressive, localized, and metastatic PCa were each measured by flow cytometry. The functional activity of Tregs was determined by their ability to suppress the proliferation of CD4+CD25- T cells. Data were analyzed using Wilcoxon rank sum test and unpaired Student's t test. RESULTS: Although levels of Tregs in the peripheral blood of patients with PCa were not significantly higher than those in healthy donors, Tregs in patients with PCa had significantly greater suppressive functionality than Tregs from healthy donors (P < 0.05). Additionally, there was a direct correlation between the serum levels of prostaglandin E(2) and Treg functionality in patients with localized PCa, using Pearson's product-moment correlation coefficient (R). CONCLUSIONS: These findings further show the potential importance of Tregs in modifying immune responses in patients with PCa. Although longer studies are necessary to confirm these findings, these studies also show for the first time the differences in Treg populations in patients with various stages of PCa, and thus, provide a basis for determining which PCa patient populations are best suited for immunotherapy trials involving the inhibition of Tregs.     

调节性T细胞在血液系统恶性肿瘤中的研究进展

胸腺产生的CD^＋4CD^＋25调节性T细胞（Treg细胞）被认为在控制自身免疫、防止移植物排斥反应、抑制抗感染自身免疫以及抑制异基因免疫反应中发挥重要作用。最近有报道此类细胞有抑制机体抗肿瘤的作用。Foxp3是Treg细胞最具特异性的蛋白分子标志物。阐述了血液系统恶性肿瘤患者CD^＋4CD^＋25去Foxp3 Treg的表达以及其对免疫治疗的潜在作用。     

肿瘤患者外周血调节性T细胞的检测及临床意义

目的:研究肿瘤患者外周血调节性T细胞水平的变化并探讨其临床意义,旨在了解肿瘤患者的免疫功能改变,为肿瘤患者临床治疗及判断预后提供依据。方法:采用流式细胞仪对40例肿瘤患者及40例正常人外周血CD4+CD25+T细胞、CD4+CD25highT细胞及CD4+CD25+Foxp3+Treg细胞水平进行检测。结果:肿瘤患者外周血中CD4+CD25+T细胞和CD4+CD25highT细胞高于正常对照组(P<0.05);CD4+CD25+Foxp3+调节性T细胞亦明显高于对照组(P<0.01)。结论:肿瘤患者细胞免疫功能明显异常,CD4+CD25+Foxp3+调节性T细胞增多可能是肿瘤患者免疫功能受抑的重要原因之一;调节性T细胞水平检测在评价肿瘤患者疗效及判断预后方面具有一定的临床价值。     

CD4+CD25+ regulatory T cells in patients with gastrointestinal malignancies: possible involvement of regulatory T cells in disease progression

BACKGROUND: Active suppression by CD4+CD25+ regulatory T cells plays an important role in the down-regulation of the response of T cells to foreign and self antigens. Experimental tumor models in mice revealed that regulatory T cells inhibit antitumor immune responses. The purpose of the current study was to demonstrate the possible involvement of CD4+CD25+ regulatory T cells in immune system impairment in patients with gastrointestinal malignancies. METHODS: The phenotypes of lymphocytes, particularly those of CD4+CD25+ T cells, were analyzed in peripheral blood in 149 patients with gastrointestinal malignancies and in ascites in 7 patients with peritoneal dissemination. In addition, cytokine production after in vitro stimulation was examined in CD4+CD25+ and CD4+CD25- T cells isolated from patients with malignant disease. RESULTS: Compared with healthy volunteers, patients with gastrointestinal malignancies had a higher proportion of CD4+CD25+ T cells in peripheral blood, due to the presence of a drastically smaller number of CD4+CD25- T cells. Among patients with gastric carcinoma, those with higher percentages of CD4+CD25+ T cells had a poorer prognosis than did those with lower percentages. CD4+CD25+ T cells also were present in greater proportions in ascites from patients who had advanced-stage disease with peritoneal dissemination. Isolated CD4+CD25+ T cells from patients with malignant disease produced interleukin (IL)-4 and IL-10 but not IL-2 or interferon-gamma; these cells also inhibited cytokine production by CD4+CD25- T cells after in vitro stimulation. CONCLUSIONS: The relative increase in CD4+CD25+ regulatory T cells may be related to immunosuppression and tumor progression in patients with gastrointestinal malignancies. This finding suggests that the use of immunomodulatory therapy to treat patients with gastrointestinal malignancies may be an effective strategy.     

CD4~+T 细胞与肿瘤免疫

CD4~+T细胞不仅辅助激活CD8~+T细胞,而且对记忆性细胞毒性T淋巴细胞(CTL)应答的产生和维持起重要作用,并具有直接的抗肿瘤功能.另外,CD4~+CD25~+ 调节性T细胞(Tregs)具有免疫负调控功能,在肿瘤免疫抑制及免疫逃逸中发挥重要作用,是肿瘤免疫治疗失败的重要原因.近年肿瘤免疫治疗已获得很大进步,相关肿瘤疫苗的研究也备受关注.     

Different procarcinogenic potentials of lymphocyte subsets in a transgenic mouse model of chronic hepatitis B

The immune response to hepatitis viruses is believed to be involved in the development of chronic hepatitis; however, its pathogenetic potential has not been clearly defined. The current study, using a transgenic mouse model of chronic hepatitis B, was designed to determine the relative contributions of the immune cell subsets to the progression of liver disease that induces hepatocellular carcinogenesis. Hepatitis B virus transgenic mice were adoptively transferred with CD4+ and CD8+ T cell-enriched or -depleted and B cell-depleted splenocytes obtained from hepatitis B surface antigen-primed, syngeneic nontransgenic donors. The resultant liver disease, hepatocyte apoptosis, regeneration, and tumor development were assessed and compared with the manifestations in mice that had received unfractionated spleen cells. Transfer of CD8(+)-enriched splenocytes caused prolonged disease kinetics, and a marked increase in the extent of hepatocyte apoptosis and regeneration. In 12 of 14 mice the transfer resulted in multiple hepatocellular carcinomas (HCCs) comparable with the manifestations seen in the mice transferred with total splenocytes. In contrast, mice that had received CD4(+)-enriched cells demonstrated lower levels of liver disease and developed fewer incidences of HCC (4 of 17). The experiment also revealed that all of the groups of mice complicated with HCC developed comparable mean numbers and sizes of tumors. B-cell depletion had no effect on disease kinetics in this model. Taken together, these results demonstrate that the pathogenetic events induced by CD8+ T-cell subset are primarily responsible for the induction of chronic liver disease that increases tumor incidence, suggesting their potential in triggering the process of hepatocarcinogenesis.     

肝细胞癌Ｔｒｅｇ和ＦＯＸＰ３的表达及其临床意义

目的　研究肝细胞癌（ＨＣＣ）患者外周血ＣＤ４＋ＣＤ２５＋调节性Ｔ细胞（Ｔｒｅｇ）和肝癌组织叉状头／翅膀状螺旋转录因子（ＦＯＸＰ３）的表达,并分析其与肝细胞癌临床病理的关系。方法　采用流式细胞仪对ＨＣＣ患者和健康志愿者外周血ＣＤ４＋ＣＤ２５＋Ｔｒｅｇ细胞进行检测,免疫组化、Ｗｅｓｔｅｒｎｂｌｏｔｔｉｎｇ法检测ＦＯＸＰ３蛋白表达水平,并结合ＨＣＣ患者临床病理特征进行分析。结果　ＨＣＣ患者外周血ＣＤ４＋ＣＤ２５＋Ｔｒｅｇ表达率为（１６.７６±５.５３）％,较健康志愿者的（６.０４±２.０１）％显著增高（Ｐ＜０.０１）。免疫组化染色肿瘤组织ＦＯＸＰ３阳性细胞数为（１０３.９５±３４.３１）个／ｍｍ２,高于癌旁组织的（２９.６１±４.６５）个／ｍｍ２（Ｐ＜０.０５）,相应肿瘤组织ＦＯＸＰ３蛋白表达也增高。ＣＤ４＋ＣＤ２５＋Ｔｒｅｇ细胞水平与肿瘤多灶性有关。结论　ＨＣＣ患者的外周血ＣＤ４＋ＣＤ２５＋Ｔｒｅｇ细胞表达增高,ＦＯＸＰ３蛋白在肿瘤组织中表达与ＣＤ４＋ＣＤ２５＋Ｔｒｅｇ细胞的变化相平行,可能与肿瘤多灶性有关。     

Midgut carcinoid patients display increased numbers of regulatory T cells in peripheral blood with infiltration into tumor tissue

INTRODUCTION: Our aim was to investigate the immune status of midgut carcinoid patients. Cancer patients generally display suppressed Th1-type immunity that disables mounting of an efficient anti-tumor response. However, little is known about patients with neuroendocrine midgut carcinoids. MATERIAL AND METHODS: Circulating regulatory T cells were determined in patient blood by staining for CD4, CD25 and FoxP3 in flow cytometric analysis. T cell proliferation was measured by Alamar Blue in response to polyclonal activation and the regulatory phenotype of patient CD25+ cells was validated by allogeneic stimulation of CFSE labelled responders. Cytokine levels in patient peripheral blood were measured by ELISA and CBA. Tumor infiltrating T cells were analyzed by immunohistochemistry and immunofluorescence. RESULTS: The results demonstrate that midgut carcinoid patients exhibit increased frequencies of circulating Tregs and patient T cells have a decreased proliferative capacity compared to healthy donors. Systemic Th1-promoting cytokines are reduced. Midgut carcinoid tumors display CD4+ and CD8+ T cell infiltration, always in the presence of regulatory CD4+FoxP3+ cells. DISCUSSION: Midgut carcinoid patients display elevated T regulatory cell numbers and T cell dysfunction. Therapeutic strategies to overcome tumor-induced Th1 immunosuppression are required in combination with anti-tumor vaccinations.     

CD4+CD25+调节性T细胞与大肠癌的关系

近来CD4 CD25 调节性T细胞对肿瘤免疫调节的抑制作用正受到越来越多的重视,许多恶性肿瘤患者外周血都存在CD4 CD25 调节性T细胞比例上调,机体抗肿瘤免疫力下降.大肠癌的发病率正逐年上升,其发病分子机制已为熟知,免疫机制研究不多,国内尚未见大肠癌与该类细胞关系的报道,现对CD4 CD25 调节性T细胞在大肠癌的发生、发展、治疗中的研究综述如下.