白血病患者异基因造血干细胞移植后T细胞免疫重建的研究

目的通过分析TCR Vβ基因片段选择性扩增,了解白血病患者异基因外周血干细胞移植后T淋巴细胞的免疫重建及其在移植物抗宿主病(GVHD)患者中的表达特点.方法采用RT-PCR扩增10例移植后患者外周血的单个核细胞的TCR Vβ 24个基因片段,分析其TCR Vβ基因的表达情况,GVHD患者的PCR产物进一步经基因扫描分析确定T细胞克隆性.结果经24个Vβ引物所分别进行的RT-PCR检测TCR Vβ各亚家族基因的表达情况,发现 10例病人外周血与正常人表达24个Vβ亚家族有明显的不同,病人的部分Vβ亚家族T细胞仍未能重建,仅表达5～22个亚家族基因;9例GVHD患者外周血仅表达2～8个TCR Vβ亚家族,其中7例均表达Vβ3.对6例GVHD患者的基因扫描显示,均存在克隆性T细胞生长.结论移植后病人外周血淋巴细胞TCR Vβ基因片段部分受抑制,部分基因片段呈选择性扩增.GVHD患者有Vβ3和Vβ8基因的优势表达,并有克隆性T细胞生成.     

急性髓性白血病患者异基因造血干细胞移植后早期T细胞免疫重建的研究

目的:监测急性髓性白血病(AML)患者接受异基因造血干细胞移植(allo-HSCT)后外周血中的T细胞受体重排删除环(TRECs)水平, 了解移植后早期的T细胞免疫重建情况.方法:AML患者15例分别在allo-HSCT前以及allo-HSCT后每隔2周收集外周血, 采用实时定量PCR法检测外周血单个核细胞(PBMNCs)中的TRECs水平;7例年龄相近的正常人外周血样本作为对照.流式检测CD45RA+细胞亚群和CD45RO+细胞亚群的阳性率.结果:allo-HSCT组移植前的TRECs平均拷贝数为(1.42±1.51)拷贝/1000 PBMNCs, 明显低于正常组的(3.03±0.45)拷贝/1000 PBMNCs水平;移植后第12周的TRECs平均拷贝数为(1.67±1.93)拷贝/1000 PBMNCs, 与正常相比仍然较低.移植后8周内以CD45RO+/CD4+细胞的扩增为主, 而外周血TRECs水平在allo-HSCT后4周左右出现短暂地升高趋势, 随后又下降, 至allo-HSCT 8周后才开始稳步上升.有急性移植物抗宿主病(aGVHD)病史的移植患者的外周血TRECs水平显著降低, 明显低于无aGVHD病史移植患者的外周血TRECs水平.3例移植后早期复发的患者的外周血TRECs水平降至基线水平或检测不到.结论:不同个体T细胞免疫重建时间存在差异;AML患者在allo-HSCT后早期(90 d内)的胸腺输出功能仍处于恢复阶段, 移植后4周内的免疫重建仍以来源于供者细胞的外周扩增为主;外周血TRECs水平可能与AML患者allo-HSCT后病情的发展、转归有关.     

异基因造血干细胞移植后免疫功能重建

异基因造血干细胞移植(allo-HSCT)，岳患者的免疫功能受到严重损伤，移植后免疫功能低下主要表现在：①免疫个体发生学过程再现的削弱；②缺乏长期稳定的供体免疫功能的转移； ③移植物抗宿主病(GVHD)对免疫功能的影响； ④胸腺功能的降低。临床实践证实，清髓性治疗后患者的免疫功能处于麻痹状态可以持续1年之久。     

异基因造血干细胞移植后NK细胞免疫重建的研究进展

异基因造血干细胞移植(allogeneic hematopoietic stem cell transplantation, allo-HSCT)是治疗血液系统恶性肿瘤有效且唯一的治愈方法,移植成功与否主要取决于移植后受者造血系统和免疫系统的恢复程度。HSCT后免疫系统的恢复,也被称为免疫重建,其中NK细胞的免疫重建最为重要,它在个体的早期防御和allo-HSCT的成败中发挥重要的作用。文章即对allo-HSCT中NK细胞免疫重建规律、促进NK细胞免疫重建的相关免疫治疗方法及疗效的进展作一综述。     

异基因外周血造血干细胞移植治疗白血病*

背景：异基因外周血造血干细胞移植是治疗白血病的有效手段。 目的：比较血缘与非血缘供者异基因外周血造血干细胞移植治疗白血病的造血重建、免疫重建、感染、移植物抗宿主病及疗效。 方法：选择接受异基因外周血造血干细胞移植治疗的白血病患者45例,其中30例患者接受血缘供者造血干细胞移植(血缘组),15例患者接受非血缘供者造血干细胞移植(非血缘组)。 结果与结论：①造血重建：血缘组白细胞和血小板重建时间均快于非血缘组(P < 0.05)。在移植后30~40 d植活证据指标测定提示异体造血干细胞在受者体内完全植活。②T细胞重建：两组移植后各时间点T细胞重建差异无显著性意义。③感染发生率：两组移植后早期感染发生率,急、慢性移植物抗宿主病发生率差异无显著性意义(P > 0.05)。④白血病复发：两组移植后复发率差异无显著性意义(P > 0.05)。⑤无病生存：两组移植后2年无病生存率差异无显著性意义(P > 0.05)。表明血缘供者异基因外周血造血干细胞移植后的造血重建较非血缘供者迅速,但两者间移植后T细胞重建、感染发生率、移植物抗宿主病及无病生存并无差异。      

异基因造血干细胞移植CD94分子在T细胞高表达的意义初探

目的检测CD94分子在T细胞表达的水平,同时探讨在异基因造血干细胞移植(HSCT)中发生移植物抗宿主病(GVHD)患者CD94分子在T细胞表达的意义。方法HSCT治疗高危白血病和遗传性溶血性贫血成功植入的儿童患者,其中同胞脐血移植(UCBT)10例,非血缘相关UCBT1例,异基因外周血造血干细胞移植(alloPBSCT)5例,在移植前后发生GVHD时采用流式细胞仪检测和比较外周血中CD94的表达,并与正常外周血水平比较。结果CD94主要表达于CD3+CD8+T细胞,正常情况下外周血和脐血T细胞表达率低于10%,其中CD4+细胞几乎不表达,低于2%。但在UCBT或alloPBSCT后CD94在CD4+T细胞和CD8+T细胞均明显增高。3例UCBT无GVHD,其余均发生了ⅠⅣ0急性GVHD。急性GVHD发生时CD4+CD94+和CD8+CD94+T细胞表达明显升高。结论异基因造血干细胞移植后发生GVHD时,T细胞高表达CD94,可能是在同种抗原的刺激下机体自我保护的结果。     

异基因造血干细胞移植后免疫功能重建

异基因造血干细胞移植(allo-HSCT)后患者的免疫功能受到严重损伤,移植后免疫功能低下主要表现在①免疫个体发生学过程再现的削弱;②缺乏长期稳定的供体免疫功能的转移;③移植物抗宿主病(GVHD)对免疫功能的影响;④胸腺功能的降低.临床实践证实,清髓性治疗后患者的免疫功能处于麻痹状态可以持续1年之久.     

干扰素-γ在异基因造血干细胞移植中的作用

干扰素-γ(IFN-γ)是最重要的Th1型细胞因子之一,可由多种类型的免疫活性细胞产生.IFN-γ具有多种生物学效应,并可能在接受了异基因造血干细胞移植(allo-HSCT)的患者发生移植物抗宿主病(GVHD)的过程中起了关键性的作用.IFN-γ最初被认为是急性GVHD过程中介导组织损伤的关键因素之一,且与GVHD严重...     

NK细胞在异基因造血干细胞移植中对移植物抗白血病效应及移植物抗宿主病作用的影响

白血病复发和移植物抗宿主病（GVHD）是异基因造血干细胞移植（allo-HSCT）后影响病人生存的主要障碍。自然杀伤细胞（NK）独特的受体表达使其具有不同于一般免疫细胞的“同种反应性”效应,这种作用使NK细胞在增强移植物抗白血病效应（GVL）的同时抑制GVHD的发生,从而达到两者的分离。NK细胞在异基因造血干细胞移植中产生GVL及GVHD作用的机制以及影响因素的深入研究可能为探讨如何改善异基因造血干细胞移植预后提供有益的参考。     

异基因造血干细胞移植后肺部并发症的发生和危险因素分析

目的探讨治疗恶性血液病异基因造血干细胞移植（allo—HSCT）后肺部并发症与相关危险因素的关系。方法回顾性分析1991年8月至2004年6月157例allo—HSCT患者的临床资料。结果71例患者发生87例次肺部并发症，其中15例患者发生2次以上肺部并发症，总发生率为45.2％。直接死于肺部并发症者37例（23．6％），发生中位时间103d（1～886d）。其中细菌性肺炎32例，间质性肺炎8例，肺真菌病3例，肺水肿3例，肺结核2例，肺栓塞1例，2种或2种以上病原所致的肺部并发症38例次。单因素分析显示：患者年龄、疾病状态、供受者关系、HLA配型相合程度及广泛型慢性移植物抗宿主病（cGVHD）是影响移植后肺部并发症的危险因素。多因素分析显示：疾病状态和广泛型cGVHD与肺部并发症的发生显著相关（P＜0．01）。结论肺部并发症是allo—HSCT后常见的并发症之一。患者移植时疾病状态和广泛型cGVHD是与allo—HSCT后肺部并发症发生相关的危险因素。     

Immune Reconstitution after Haploidentical Hematopoietic Stem Cell Transplantation

Haploidentical hematopoietic stem cell transplantation (HSCT) offers the benefits of rapid and nearly universal donor availability and has been accepted worldwide as an alternative treatment for patients with hematologic malignancies who do not have a completely HLA-matched sibling or who require urgent transplantation. Unfortunately, serious infections and leukemia relapse resulting from slow immune reconstitution remain the 2 most frequent causes of mortality in patients undergoing haploidentical HSCT, particularly in those receiving extensively T cell–depleted megadose CD34⁺ allografts. This review summarizes advances in immune recovery after haploidentical HSCT, focusing on the immune subsets likely to have the greatest impact on clinical outcomes. The progress made in accelerating immune reconstitution using different strategies after haploidentical HSCT is also discussed. It is our belief that a predictive immune subset–guided strategy to improve immune recovery might represent a future clinical direction.     

Longitudinal Analysis of T-Cell Receptor Variable β Chain Repertoire in Patients with Acute Graft-versus-Host Disease after Allogeneic Stem Cell Transplantation

T-cell receptor variable β chain (TCRBV) repertoire spectratyping involves the estimation of CDR3 length distributions for monitoring T-cell receptor diversity and has proven useful for analyses of immune reconstitution and T-cell clonal expansions in graft-versus-host disease (GVHD) and graft-versus-leukemia after allogeneic stem cell transplantation. We performed a longitudinal spectratype analysis of 23 TCRBV families in 28 patients who underwent allogeneic T cell–depleted peripheral blood stem cell transplantation. Sixteen patients subsequently developed acute GVHD. We recently developed statistical methods that bring increased power and flexibility to spectratype analysis and allow us to analyze TCRBV repertoire development under appropriately complex statistical models. Applying these methods, we found that patients with acute GVHD demonstrated TCRBV repertoire development statistically distinct from that repertoire development in patients without GVHD. Specifically, GVHD patients showed spectratypes indicative of lower diversity and greater deviation from the spectratypes expected in healthy individuals at intermediate times. Most individual TCRBV subfamilies had spectratypes statistically distinguishable between GVHD and non-GVHD patients at 6 months after transplantation. These results suggest that the T-cell receptor repertoire perturbations associated with acute GVHD are widely spread throughout the TCRBV families.     

Reconstitution and Phenotype of Tregs in CMV Reactivating Patients Following Allogeneic Hematopoietic Stem Cell Transplantation

In experimental and clinical settings Tregs prevent graft-versus-host disease (GvHD) by inhibiting the proliferation and function of conventional T cells (Tconv). The suppressive potency of Tregs might also lead to the inhibition of protective antiviral T cell responses. As the control of CMV reactivation is important to improve the clinical outcome in allogeneic HSCT, we analyzed the Treg reconstitution in CMV reactivating patients with and without GvHD (n=47) in the first 6 months following transplantation. Most importantly, CMV reactivation does not correlate with the numerical reconstitution of CD4⁺CD25^highCD127^? Tregs. During CMV reactivation the proportion of Tregs within the CD4⁺ T cell population decreased significantly independent of GvHD manifestation. A comprehensive FACS analysis was performed in order to characterize the phenotype of Tregs and Tconv cells in greater detail for activation, co-stimulation, proliferation, suppressive function and migratory capability. Interestingly, Tregs of patients with CMV reactivation showed a significantly higher CXCR3 expression. CD4⁺ Tconv cells expressed significantly higher protein levels of the proliferation marker Ki67 correlating with a numerical increase of CD4⁺ T cells. Our results indicate that Tregs are not inhibiting pathogen clearance by Tconv following HSCT, which is of high relevance for future Treg cell-based clinical trials in allogeneic HSCT.     

Recent Advances in Allogeneic Hematopoietic Stem Cell Transplantation for Acute Myeloid Leukemia

Allogeneic hematopoietic stem cell transplantation remains an important treatment modality for patients with acute myeloid leukemia (AML). Recent advances have extended donor availability for patients without matched donors. Transplantation is now increasingly offered to older patients, including those above 70 years and less fit individuals. Better prognostic models are being developed. Proceeding faster to transplantation with haploidentical donors if an urgent transplant is needed, such as in patients with detectable minimal residual disease, may allow more patients to get to transplant, and it is hoped more will be cured from their disease. With continuous improvements in treatment-related toxicity and mortality, relapse has become the most important cause of treatment failure, and novel approaches are needed to make the next big leap in the treatment of this disease with transplantation. In this review we aim to summarize recent advances and provide future research directions in the transplantation for patients with AML.     

Long-Term Immune Reconstitution and Infection Burden after Mismatched Hematopoietic Stem Cell Transplantation

Mismatched unrelated donor (MMUD) or umbilical cord blood (UCB) can be chosen as alternative donors for allogeneic stem cell transplantation but might be associated with long-lasting immune deficiency. Sixty-six patients who underwent a first transplantation from either UCB (n = 30) or 9/10 MMUD (n = 36) and who survived beyond 3 months were evaluated. Immune reconstitution was prospectively assessed at sequential time points after transplantation. NK, B, CD4⁺, and CD8⁺ T cells and their naïve and memory subsets, as well as regulatory T cells (Treg), were studied. Detailed analyses on infections occurring after 3 months were also assessed. The 18-month cumulative incidences of infection-related death were 8% and 3%, and of infections were 72% and 57% after MMUD and UCB transplantation, respectively. Rates of infection per 12 patient-month were roughly 2 overall (1 for bacterial, .9 for viral, and .3 for fungal infections). Memory, naïve CD4⁺ and CD8⁺T cells, naïve B cells, and Treg cells reconstitution between the 2 sources were roughly similar. Absolute CD4⁺T cells hardly reached 500 per μL by 1 year after transplantation and most B cells were of naïve phenotype. Correlations between immune reconstitution and infection were then performed by multivariate analyses. Low CD4⁺ and high CD8⁺T cells absolute counts at 3 months were linked to increased risks of overall and viral (but not bacterial) infections. When assessing for the naïve/memory phenotypes at 3 months among the CD4⁺ T cell compartment, higher percentages of memory subsets were protective against late infections. Central memory CD4⁺T cells protected against overall and bacterial infections; late effector memory CD4⁺T cells protected against overall, bacterial, and viral infections. To the contrary, high percentage of effector- and late effector-memory subsets at 3 months among the CD8⁺ T cell compartment predicted higher risks for viral infections. Patients who underwent transplantation from alternative donors represent a population with very high risk of infection. Detailed phenotypic analysis of immune reconstitution may help to evaluate infection risk and to adjust infection prophylaxis.     

Use of Multivariate Immune Reconstitution Patterns to Describe Immune Reconstitution after Allogeneic Stem Cell Transplantation in Children

Immune reconstitution after hematopoietic stem cell transplantation (HSCT) is a complex process. Impacts of the reconstitution of different immune cells over time are complex and difficult to understand. New mathematical models are needed to better understand this process. In this study, we used principal component analysis to better analyze the process of immune reconstitution after HSCT. Forty-six consecutive patients receiving HSCT for malignant and nonmalignant disorders were included in the study. All patients were followed for at least 24 months after transplantation with regular blood sampling for analysis of lymphocyte subset numbers and function. Exponentially transformed lymphocyte subset counts and lymphocyte functional markers were analyzed to identify major trends in the reconstitution process. Using our multivariate model for mapping immune reconstitution after HSCT, we showed that dysfunctional reconstitution patterns precede severe complications, such as chronic graft-versus-host disease, relapse, and death.