CD+4 CD+25调节T细胞的生物学功能及其在移植物抗宿主病中作用的研究进展

 CCD+4 CD+25 调节T（Treg）细胞具有免疫无能性和免疫抑制性两大功能特征,是抑制性T细胞的一种亚群。能抑制效应细胞CD+4 T细胞和CD+8 T细胞的活化与增殖,从而有效抑制免疫系统对外来器官产生的排异反应,减轻了造血干细胞移植（HSCT）术后移植物抗宿主病（GVHD）,而且不影响移植物抗白血病（GVL）效应,从而在移植免疫耐受中发挥重要的作用。     

异基因造血干细胞移植后白血病复发的危险因素

目的探讨异基因造血干细胞移植后白血病复发的危险因素。方法回顾性选择71例行异基因造血干细胞移植术的白血病患者,采用单因素、COX多因素回归法分析71例患者性别、年龄、疾病类型、诱导疗程数、初诊白细胞计数、巨细胞病毒感染、移植物来源、供受者HLA配型、急性移植后移植物抗宿主病、慢性移植后移植物抗宿主病与复发的相关性。结果71例患者中14例复发。单因素分析结果表明,初诊白细胞计数、诱导疗程数、移植物来源及慢性移植物抗宿主病史是异基因造血干细胞移植后复发的危险因素,P<0.05;Cox多因素回归分析结果表明,诱导疗程数多、无慢性移植物抗宿主病是异基因造血干细胞移植后复发的独立危险因素,P<0.05。结论无慢性移植物抗宿主病、诱导疗程数多是异基因造血干细胞移植后复发的危险因素。     

移植物抗宿主病的治疗及移植相关肝损伤的研究进展

异基因造血干细胞移植使治愈血液系统恶性疾病成为可能.但在移植后出现的移植物抗宿主病及重要脏器损伤越来越成为移植后的主要并发症及非复发死亡的重要原因.目前移植物抗宿主病的治疗以免疫抑制为主,但部分患者疗效欠佳,并可能减弱移植物抗白血病效应、增加感染机会.对于如何预防及早期识别移植物抗宿主病,不同药物方案对比以及对于肝脏相...     

CD自杀基因系统对T淋巴细胞作用的实验研究

异基因骨髓移植是治愈白血病及某些实体肿瘤的有效手段,但其并发症——移植物抗宿主病(GVHD)目前仍具有相当高的发病率和死亡率,是影响移植成功的主要障碍.在移植前体外去除供者骨髓中的T淋巴细胞可有效减轻GVHD)的发生,但T细胞的去除可使移植物失去移植物抗白     

成年人脂肪源间充质干细胞治疗急性移植物抗宿主病后CD+8 T细胞亚群的变化

  目的 初步探讨成年人脂肪源间充质干细胞（AMSC）治疗急性移植物抗宿主病（aGVHD）的分子机制。方法 3例行异基因造血干细胞移植术后发生aGVHD的患者,以每1 kg体重2×106个细胞剂量静脉输注AMSC;首先应用尼龙毛柱分离外周血T淋巴细胞,再经CD8磁珠分选出CD+8 T淋巴细胞,应用流式细胞术检测发生aGVHD患者使用AMSC前后外周血CD+8 T细胞亚群的变化。结果 与输注AMSC前相比,输注AMSC后,CD+8 T细胞中的CD+8 CD-28亚群显著上调,同时,患者的aGVHD得以有效控制。结论 AMSC治疗aGVHD的作用机制可能与其上调CD+8 CD-28 T细胞亚群有关,CD+8 T细胞可能是AMSC作用的靶细胞。     

非清除性异基因外周造血干细胞移植治疗难治复发性急性白血病

目的 :探讨非清除性异基因干细胞移植在难治性急性白血病治疗中的作用。方法 :3例难治性急性白血病 ,采用环胞霉素 A、环磷酰胺、阿糖胞苷或抗淋巴细胞球蛋白等作非清除性预处理的异基因外周造血干细胞移植。结果 :移植过程顺利 ,+ 10天～ + 14天中性粒细胞 >0 .5× 10 9/ L。 + 14天～ + 2 1天血象和骨髓象达 CR。 3例均达嵌合性植入。无移植物抗宿主病。 2例随访 116 d仍健在。 1例 + 5 6 d移植排斥及白血病复发。结论 :非清除性异基因干细胞移植简便、安全、并发症轻 ,对难治性急性白血病有较好疗效。     

树突状细胞在造血干细胞移植后重建及与临床结果的相关性

 异基因造血干细胞移植后,供体树突状细胞（DCs）在受者体内逐步重建。DC1、DC2在宿主体内重建速度各异。一些内源或外源性因素影响DCs重建。异基因和自体造血干细胞移植各有自己的DCs重建规律,并与移植后临床结果如移植物抗宿主病、移植后感染、移植物抗白血病效应具有相关性。     

GVL作用研究现状

移植物抗白血病作用(GVL)是人们在长期异基因移植医疗实践及实验研究过程中发现的一种移植物抗肿瘤作用。与异基因骨髓移植(allo-BMT)相比，自体干细胞移植(ASCT)取材方便、术后无移植物排斥反应和不发生移植物抗宿主……     

移植后树突状细胞、亚群重建规律及其与急性移植物抗宿主病的关系

 异基因干细胞移植后树突状细胞（DC）恢复的特点是移植后DC细胞亚群均较移植前水平低,单核细胞样DC在移植后300 ~ 400 d可以恢复正常水平,浆细胞样DC恢复很慢。它的重建受到粒细胞刺激因子、前炎性的细胞因子及间充质干细胞的影响,与异基因移植CD+34剂量无关。通过分析DC与移植物抗宿主病关系的分析,发现低数量的DC会导致高的GVHD的发生率,并有学者对这种现象的机制进行了解释。就移植后树突状细胞、亚群重建规律及其与急性移植物抗宿主病的关系的主题进行综述。     

纯化的自体CD34+细胞移植治疗恶性淋巴瘤

自体造血干细胞移植是NHL患者取得长期生存的重要治疗方法之一。但是,自体移植物中肿瘤细胞的污染,成为auto-HSCT后NHL复发的主要原因之一：因此,体外净化去除移植物中可能存在的残留肿瘤细胞,对于降低auto-HSCT后的复发率具有重要意义。本文就NHL自体造血干细胞移植中,CD34^ 细胞分选的机制、方法以及CD34阳性细胞移植在淋巴瘤治疗中的疗效做一简单综述。     

Marked increase of CD57+CD16- cells in long-term survivors of graft-versus-host disease after allogeneic bone marrow transplantation.

We have evaluated long-term serial changes in the immunological state from soon after allogeneic bone marrow transplantation (BMT) In 44, mainly leukemia patients with respect to changes in lymphocyte surface markers. Absolute numbers of cluster designation (CD)2+, CD20+ and human lymphocyte antigen-DR+ (HLA-DR+) cells recovered to within their normal ranges three months, one year and two years, respectively, after BMT. The reversal of the CD4+: CD8+ ratio persisted for five years or more but returned to normal after six years. CD57+CD16- cells were markedly increased from three mo up to a maximum of five years after transplantation; they were increased between three and six months after transplantation irrespective of graft-versus-host disease (GVHD), but changes after one year or more differed among patients without GVHD, with acute GVHD, with acute and chronic GVHD or with chronic GVHD. Absolute numbers of CD57+CD16- cells tended gradually to return to normal after one year or more in the group without GVHD but only after six years in patients in the other three GVHD groups.     

The graft content of donor T cells expressing gamma delta TCR+ and CD4+foxp3+ predicts the risk of acute graft versus host disease after transplantation of allogeneic peripheral blood stem cells from unrelated donors.

PURPOSE: Recently, high numbers of regulatory T cells within the stem cell graft were described to be associated with less graft-versus-host disease (GVHD) after related peripheral blood stem cell transplantation (PBSCT). Studies in mice also suggest a distinct role of gamma delta TCR(+) T cells in mediating GVHD. Therefore, the aim of this study was to define the yet-unknown role of regulatory and gamma delta TCR(+) T cells in human PBSCT from unrelated donors. EXPERIMENTAL DESIGN: The frequency of both T-cell subsets within the graft was analyzed in 63 patients receiving unrelated allogeneic PBSCT. The respective amounts were quantified by flow cytometry and PCR and further correlated with clinical outcome. RESULTS: The grafts contained a median of 11.2 x 10(6)/kg CD4(+)foxp3(+) and 9.8 x 10(6)/kg gamma delta TCR(+) T cells, respectively. Patients receiving more CD4(+)foxp3(+) cells had a lower cumulative incidence of acute GVHD II-IV (44% versus 65%, P=0.03). Interestingly, in patients who received higher concentrations of donor gamma delta TCR(+) T cells, acute GVHD II-IV was more frequent (66% versus 40%, P=0.02). In multivariate analysis, only the graft concentration of gamma delta TCR(+) T cells (P=0.002) and a positive cytomegalovirus status of the recipient (P = 0.03) were significantly associated with the occurrence of acute GVHD II-IV. CONCLUSION: Graft composition of T-cell subsets seems to affect the outcome of patients receiving allogeneic PBSCT from unrelated donors. Therefore, selective manipulation or add-back of particular subsets might be a promising strategy to reduce the incidence of GVHD.     

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。     

CD4+CD25+ regulatory T cells in human hematopoietic cell transplantation

Naturally occurring CD4+CD25+ regulatory T cells (T(reg)) are differentiated T lymphocytes actively involved in the control of peripheral immunity. Over the past few years, a number of animal studies have demonstrated the critical role of these cells in the outcome of allogeneic hematopoietic stem cell transplantation (HCT). In these models, T(reg) can exert a potent suppressive effect on immune effector cells reactive to host antigens and prevent graft versus host disease (GVHD) while preserving the graft-versus-leukemia effect (GVL). The present review summarizes current knowledge on the role of T(reg) populations in humans following allogeneic HCT. Recent investigations focusing on T(reg) in transplant patients have generated conflicting results mostly due to the use of different parameters to assess T(reg). Nonetheless, these studies suggested that an imbalance between T(reg) and effector cells during immune reconstitution can substantially impair regulatory mechanisms and contributes to the development of GVHD. Building on these studies, a number of therapeutic strategies are being developed to positively modulate T(reg) pools in vivo and prevent or even correct GVHD. Conversely, clinical interventions can also be envisaged to decrease T(reg) activity in vivo and enhance the GVL effect. These potential strategies are discussed herein. Coming years will undoubtedly yield additional knowledge on how to use T(reg) subsets in vivo and successfully control and modulate immune responses in patients post-HCT.     

Transplantation of highly purified peripheral blood CD34+ cells from HLA-mismatched parental donors in 14 children: evaluation of early monitoring of engraftment.

HLA-mismatched family members may represent an important cell source for patients that require stem cell transplantation but lack both a matched sibling donor and a closely matched unrelated donor. We report the outcome of 19 transplantations from HLA two- or three- loci mismatched parental donors in which 14 pediatric patients with hematological malignancies or other disorders, received a median of 21.5 x 106 (range, 5.4-58) highly purified CD34+peripheral blood stem cells (PBSC), as well as 4.7 x 104 (range, 0.4-12) donor T cells per kg body weight. T cell depletion was performed using a two-step CD34-positive selection on two different magnetic beads devices. Ten of 14 patients presented with rapid myeloid engraftment. The four patients who presented with graft failure (two non-engraftments, two rejections) received a second stem cell graft and one a third. Graft rejection was detected early by polymerase chain reaction (PCR) analysis of FACS-sorted T cells. Eight of the 14 patients are still alive after a median observation period of 15. 6 months (range, 3-31.3) with full donor chimerism in all hematopoietic cell lineages. No acute organ graft-versus-host disease (GVHD) and no chronic GVHD have occurred. One patient experienced relapse of leukemia. We conclude that transplantation of allogeneic PBSC from haploidentical donors will open new perspectives for pediatric patients for whom an HLA-matched stem cell graft is not available. Close monitoring of recipient and donor hematopoiesis might be of clinical value, to recognize early engraftment or rejection.     

Rapid engraftment after allogeneic transplantation of density-enriched peripheral blood CD34+ cells in patients with advanced hematologic malignancies.

BACKGROUND: Acute graft versus host disease (GVHD) remains a major cause of morbidity and mortality after allogeneic hematopoietic cell transplantation. Preclinical studies have suggested that a T-cell subset with a CD4-/CD8- double-negative (DN) T-cell phenotype is capable of suppressing GVHD. Double-negative T cells can be mobilized into the peripheral blood with granulocyte colony-stimulating factor (G-CSF) and enriched by density centrifugation. The current study was performed to study the feasibility and safety of applying a density gradient separation technique for enrichment of CD34+ and DN T cells, while depleting CD4+ and CD8+ single-positive (SP) T cells from peripheral blood progenitor cells (PBPCs) for the purpose of allogeneic transplantation. METHODS: Twenty-five patients with advanced hematologic malignancies were treated with a myeloablative preparative regimen consisting of fractionated total body irradiation, etoposide, and cyclophosphamide. Human leukocyte antigen identical donors were mobilized with G-CSF PBPC collected by apheresis. The apheresis product was applied to a single-step density gradient, and the low-density cell population was collected. The low-density cell population was infused as the sole source of allogeneic cells after myeloablative therapy. Graft versus host disease prophylaxis consisted of cyclosporine with or without prednisone. RESULTS: CD34 cell recovery was efficient with a median 72% yield, providing for a median CD34+ cell dose of 6.5 x 10(6)/kg (range,1.0- 13.9 x 10(6)/kg). CD3+CD4+ or CD3+CD8+ SP T cells were depleted by a median of 94.4% (range, 58.8- 99.2%), and the ratio of CD34+:SP T cells increased 10-fold. Double-negative T cells were depleted by 92% (range, 18.8- 99.4%), thus the ratio of DN:SP T cells increased less than 2-fold in 71% of apheresis samples tested. Hematopoietic engraftment was rapid, and there was no occurrence of graft failure in examinable patients. Median time to absolute neutrophil count greater than 0.5 x 10(9)/L and platelet count greater than 20 x 10(9)/L was 10.5 and 12 days, respectively. The incidence of Grade 2-4 acute GVHD was 26% (95% confidence interval [CI], 6-45%), although not all patients were examinable due to an unexpectedly high nonrecurrence mortality that at Day 180 was 62% (95% CI, 40-83%). CONCLUSIONS: These data suggest that T-cell subset manipulation via density gradient separation is a safe procedure and allowed rapid hematopoietic recovery. Selective enrichment of a donor DN T-cell subset was observed in only a few and was not associated with a reduced incidence of GVHD. However, the low-density selected cells still resulted in GVHD, and there was a high treatment-related mortality.     

A high proportion of donor CD4+ T cells expressing the lymph node-homing chemokine receptor CCR7 increases incidence and severity of acute graft-versus-host disease in patients undergoing allogeneic stem cell transplantation for hematological malignancy.

CC-chemokine receptor 7 (CCR7), a chemokine receptor required for transmigration into lymphoid organs, is only expressed by naive and central memory T cells. T cells with a capacity of homing into lymphoid organs can initiate acute graft-versus-host disease (GVHD) in mice and respond vigorously in vitro to alloantigens in humans, but their impact on clinical outcomes is unknown. We evaluated prospectively the distribution of naive, central memory and CCR7neg memory T-cell subsets in 39 bone marrow and 23 granulocyte colony-stimulating factor-mobilized peripheral blood stem cell allografts and investigated their impact on patient outcomes. Ranges of the relative proportions of CCR7+ cells within CD4+ and CD8+ T-cell populations were broad, but did not differ between the two sources of allografts. By multivariate analysis, high percentage of donor-derived CD4+CCR7+ T cells (>73.5%) significantly correlated with incidence, earliness of onset and severity of acute GVHD, conferring the highest adjusted hazard ratio (HR=3.9; 95% confidence interval 1.4-10.8; P=0.008) without interfering in other clinical events, especially chronic GVHD and relapse. Determination of the percentage of CD4+CCR7+ T cells in the graft provides a predictive indicator of acute GVHD. Partial depletion of this subset may reduce the risk of acute GVHD while preserving immunotherapeutic effects.     

Correlation between CD4+CD25+Treg Cells and CCR4 in Nasopharyngeal Carcinoma

OBJECTIVE CD4+CD25+ T regulatory (Treg) cells are a population of T cells which suppress an overactive immune system. CCR4 is a chemokine receptor involved in the recruitment of lymphocytes. Nasopharyngeal carcinoma (NPC) is resistant to immunosurveillance, owing to the increased number of tumor-infiltrating Treg cells which are recruited to the tumor by CCR4.METHODS The percentage of CD4+CD25+Treg cells and CCR4+ cells in tissue or peripheral blood (PB) lymphocytes of patients with untreated NPC or normal subjects was analysed by flow cytometry. RESULTS In both tissue and PB lymphocytes, the percentage of CD4+CD25+ Treg cells and CCR4+ cells was significantly elevated in patients with NPC in comparison with that in the normal tissue of controls. Furthermore, in the patients with NPC, a higher percentage of CD4+CD25+ Treg cells was found in the tumor-infiltrating (T1) lymphocyte population than in the PB population. In the NPC patient group, a general trend towards an increased percentage of Tl Treg cells was found in the patients with advanced stage NPC. The number of CD4+CD25+ Treg cells was positively related to the number of CCR4+ cells in the tumor and in the PB of the patients with NPC, while the number of CD4+CD25+ Treg cells was negatively related to the number of CD4+CD25- T cells.CONCLUSION Immunosuppression was observed in NPC, especially at the tumor sites. CD4+CD25+ Treg cells may suppress CD4+CD25- T cells. CCR4 may have an important role in the recruitment of CD4+CD25+ Treg cells to tumor sites, thus causing resistance to immunosurveillance.     

CD34 cell dose and chronic graft-versus-host disease after human leukocyte antigen-matched sibling hematopoietic stem cell transplantation

Chronic graft-versus-host disease (GVHD) is a major cause of morbidity and mortality after allogeneic hematopoietic stem cell transplantation. Recent reports suggest that chronic GVHD is more frequent after G-CSF - mobilized peripheral blood mononuclear cell (G-PBMC) transplantation compared to marrow transplantation from human leukocyte antigen (HLA)-matched siblings. Furthermore, higher numbers of CD34 positive cells in G-PBMC grafts were associated with an increased risk of chronic GVHD, whereas a correlation between CD34 cell numbers and chronic GVHD has not been reported after bone marrow transplantation. Potential mechanisms that might explain the association between G-PBMC CD34 numbers and chronic GVHD include enhanced antigen presentation to donor T cells by large numbers of transplanted CD34 cells or their dendritic cell progeny, which may enhance GVHD induction. However, these mechanisms remain highly speculative and are not supported by experimental data. This review discusses implications of CD34 cell dose adjustments in HLA-identical sibling G-PBMC transplantation and weighs the benefits and risks with respect to chronic GVHD, hematopoietic recovery, immune reconstitution and relapse.