异种移植超急性排斥反应的研究进展

异种移植排斥反应一般分为超急性排斥（xenogeneic hyperacute rejection，HAR），延迟性排斥（又称急性血管性排斥），急性细胞性排斥和慢性排斥。     

细胞粘附分子与异种移植排斥反应

排斥反应是导致异种移植失败的主要原因。在异种移植排斥中，移植物血管内皮细胞活化是关键，而细胞粘附分子的表达与内皮细胞的活化以及白细胞趋化均关系密切，更成为异种移植排斥反应中不可获缺的重要环节。本文综述了细胞粘附分子的生物学特点、在异种移植排斥反应中的诱导和表达及其在治疗中的研究进展。     

细胞粘附分子与异种移植排斥反应

排斥反应是导致异种移植失败的主要原因。在异种移植排斥中,移植物血管内皮细胞活化是关键,而细胞粘附分子的表达与内皮细胞的活化以及白细胞趋化均关系密切,更成为异种移植排斥反应中不可获缺的重要环节。本文综述了细胞粘附分子的生物学特点、在异种移植排斥反应中的诱导和表达及其在治疗中的研究进展。     

猪异种抗原与异种移植排斥反应

异种移植已成为当今器官移植的研究热点。移植后严重的排斥反应仍是阻碍异种移植成功的主要问题，供器官血管内皮细胞上的主要异种抗原与异种移植后的一系列排斥反应关系密切。本文将介绍近几年来对半乳糖α１，３－半乳糖在异种移植排斥反应机理方面的研究及相应防治措施。     

小鼠异种胰岛移植排斥反应研究

目的观察小鼠对肾被膜下异种胰岛移植物的排斥反应规律和免疫病理学特点。方法将大鼠胰岛移植到小鼠肾被膜下,分别于术后当日、第1、2、4、5、6天取出移植物,研究异种胰岛排斥的病理组织学形态特点和过程。结果异种胰岛移植可有功能存活(5.9±1.2)d,在自然情况下,胰岛在术后6d左右完全被排斥,术后4d胰岛形态已不完整,单核细胞浸润明显增多。移植物附近未发现IgG+IgM的免疫沉积。结论异种胰岛的排斥反应是一个以单核细胞浸润为特征的渐进性过程,移植后4~6d达排斥高峰,CD4+T细胞可能在急性细胞性排斥反应中起重要作用,而体液免疫没有或很少参与。     

猪供人异种移植超急性排斥反应体外实验模型的初步研究

目的 研究通过转基因方法在猪主动脉内皮细胞上表达人ＣＤ５９蛋白,抑制猪供人移植超急性排斥反应。方法 体我２的猪主动脉和人脐静脉内皮细胞,用免疫荧光和免疫组化的方法得到鉴定。构建含入ＣＤ５９ＣＤＮＡ的真核细胞表达载体ＬＸＳＮ－ＣＤ５９,限制性内切酶酶切,琼脂糖凝胶电泳和多聚酶链反应（ＰＣＲ）法鉴定。脂质体转染法将ＬＸＳＮ－ＣＤ５９转化进猪血管内皮细胞,Ｇ４１８筛选得到稳定转化子流式细胞仪筛选得到表达     

FTY720在异种胰岛移植排斥反应中的作用

目的　研究FTY72 0单独用药和联合应用FTY72 0及环孢素A (CsA)在抑制猪 大鼠异种胰岛移植排斥反应中的作用。方法　大鼠肾被膜下移植成年猪胰岛 (APIs) 2 μl,单独应用FTY72 0 ( 1.0mg/kg·d和 3 .0mg/kg·d)和联合应用FTY 72 0及CsA(FTY 72 0 1.0mg/kg·d +CsA15mg/d和FTY72 0 3 .0mg/kg·d +CsA15mg/kg·d)。移植后 12d应用免疫组织化学染色方法来观察移植物内细胞浸润情况。结果　单独应用FTY72 0不能抑制API异种移植排斥反应的发生 ;在FTY72 0 +CsA组 ,排斥反应过程被明显抑制。在移植后第 12天 ,可以见到大量完整的API ,仅偶尔有细胞浸润。内分泌组织完整。结论　在猪 大鼠异种胰岛细胞模型中 ,联合应用FTY72 0及CsA可有效抑制排斥反应直到移植后第 12天 ,且未出现任何明显毒性作用。     

转基因猪异种移植抗排斥研究进展及其潜在风险

随着免疫学的飞速发展和功能强大的免疫抑制药物的不断涌现 ,器官移植已成为许多终末期器官疾患的主要治疗措施之一 ,降低了患者因为单一或少数器官严重受损、失去功能而导致死亡的危险性 ,并极大地提高了患者的生活质量。但是 ,目前临床同种器官移植面临着越来越严重的供器官短缺局面 ,促使人们开始认真地考虑异种移植。在众多的候选动物中 ,猪的脏器大小 ,生理和代谢方面与人类近似 ,易于培植 ,价格较低而社会阻力又相对较小 ,所以是公认的最适合用作异种移植供体的物种。一、人体对猪器官排斥的主要类型及其机制(一 )超急性排斥 (ｈｙｐ…     

异种器官移植过程中预防T细胞排斥反应的研究进展

异种器官移植是解决供体器官短缺的最适途径。基因工程已很大程度上克服了异种器官移植出现的超急性排斥反应等早期障碍,但是异种器官的成功存活还需要预防T细胞介导的急性排斥反应。目前异种器官移植中预防T细胞免疫排斥的方案分为3种：从基因水平进行改造减少T细胞免疫排斥反应、直接阻断T细胞免疫排斥反应、诱导移植受体的免疫耐受能力。在临床应用前, 对这些方案进行研究和优化, 有望实现异种器官移植后的长期存活。     

异种移植中的排斥反应及其对策研究进展

随着器官移植技术在临床的广泛应用 ,同种异基因器官供体远不能满足受体的需要 ,异种移植有可能解决这一矛盾。非灵长类动物 ,特别是猪 ,因其易于饲养 ,且器官大小及免疫学、生理学特性与人类有一定的相似性 ,作为最适的异种移植器官供体已日益引起人们的关注[1,2 ] 。但由于人类和猪两种源间存在巨大的抗原差异 ,针对异种移植物的免疫应答比对同种移植物更加强烈。本文现对近年来有关异种移植排斥机制及其防治策略作一简要回顾。一、异种移植排斥机制1.超急性排斥反应 (hyperacuterejection,HAR):HAR以血栓形成、出血及异种移植物破坏为…     

Negligible role for NK cells and macrophages in delayed xenograft rejection

Abstract Hyperacute rejection (HAR) of a discordant xenograft can be avoided by complement manipulation, but delayed xenograft rejection (DXR) still leads to graft loss. It is generally assumed that macrophages and NK cells play key roles in DXR. In the present study the survival times and cellular infiltrate following guinea pig to rat heart transplantation was analyzed in the course of DXR, following aspecific and specific manipulation of macrophages and NK cells. HAR was overcome by a single injection of cobra venom factor 1 day before heart transplantation. To aspecifically reduce the inflammatory response dominating DXR, dexamethasone (DEXA) was given. Treatment with DEXA markedly reduced infiltration by NK cells, macrophages, and granulocytes. It also led to prolonged graft survival times (median survival of 0.4 days, n = 10, P < 0.05). In the second series of experiments the specific roles of NK cells and macrophages in DXR were further assessed. Monoclonal antibody 3.2.3 was used to selectively deplete NK cells. Liposome‐encapsulated dichloromethylene biphosphonate was given to achieve macrophage depletion. Neither of these specific treatments, alone or combined, led to prolonged graft survival. Immunohistology revealed that at day 2 after transplantation no NK cells or macrophages were present in grafts from the combined treatment group. Only a mild infiltration of granulocytes was observed. Collectively, these results strongly suggest that NK cells and macrophages are not likely to be pivotal cell types in DXR.     

Pathogenesis and pathology of delayed xenograft rejection in pig-to-rhesus monkey cardiac transplantation

It has been recognized that delayed xenograft rejection (DXR) is the major barrier to the acceptance of xenotransplantation after overcoming hyperacute rejection. OBJECTIVES: This study sought to investigate the pathogenesis and pathology of delayed xenograft rejection following pig-to-rhesus monkey heart xenotransplantation. METHODS: Heterotopic xenogeneic heart transplants in the abdominal cavity were performed using piglet donors to four monkey recipients. Complete complement depletion was achieved in the recipients with repetitive doses of high-activity cobra venom factor (Y-CVF). The recipients were immunosuppressed with a combination of cyclosporine, cyclophosphamide, and steroids. Sera were analyzed for C3 and C4 levels and complement activity and anti-pig endothelial xenoantibody. The grafts were examined histopathologically and immunohistochemically for C3, C4;C5b-9, IgM, IgG, tumor necrosis factor-alpha (TNF-alpha), intercellular adhesion molecule-1(ICAM-1), CD57(NK cells), CD68 (macrophages), CD4, and CD8. RESULTS: Xenografts survived 8, 10, 13, and 13 days respectively, all developing DXR. Venous thrombosis was the outstanding feature within DXR xenografts, complicated by interstitial edema, local hemorrhage, myocardial necrosis, and mild to moderate cellular infiltration. The serum C3 levels and complement activity decreased to almost 0 from the day of transplantation due to treatment with Y-CVF. The C4 level began to decrease 2 to 4 days before the cardiac xenografts lost their function. Anti-pig endothelial xenoantibody also decreased after transplantation, slightly increasing during DXR. All rejected xenografts showed C3, C4, C5b-9, IgG, and IgM deposits to various degrees. Large numbers of macrophages (50% of total leukocytes) infiltrated the entire xenograft with a few natural killer cells (8% to 10%), as well as some CD4+ T cells (15%) and CD8+ T cells (25%). Upregulation of ICAM-1 on graft endothelial cells and TNF-alpha in the interstitium were also demonstrated in the rejected heart. CONCLUSION: Both humoral and cell-mediated immunologic reactions may play important roles in the pathogenesis of DXR. Besides C3, C4, C5b-9, IgM, and IgG destroying the xenograft, NK cells, macrophages, and CD4+ and CD8+ T cells may further aggravate the development of DXR.     

The role of monocytes and macrophages in delayed xenograft rejection

Abstract: Despite the development of successful strategies for averting hyperacute rejection (HAR) in both small and large animal xenograft models, a delayed xenograft rejection (DXR) ultimately occurs. This process is characterized by endothelial cell activation and graft infiltration with activated monocytes and natural killer (NK) cells. We evaluated the role of monocytes and macrophages in a guinea pig-to-rat model of DXR. Our results suggest that specific interactions between these cells and the xenograft occur that result in their activation, since adoptive transfer of xenoactivated splenocytes significantly accelerated both DXR and allograft rejection, while adoptive transfer of alloactivated splenocytes did not. Furthermore, while normal splenocytes caused antibody-dependent cell-mediated cytotoxicity (ADCC) of xenogeneic endothelial cells, xenoactivated splenocytes caused significantly greater endothelial cytotoxicity by antibody-independent mechanisms. Both normal and xenoactivated splenocytes were significantly less cytotoxic if adherent cells, consisting predominantly of monocytes and macrophages, were first removed. In vivo recipient macrophage depletion, using liposome-encapsulated dichloromethylene diphosphonate, did not influence DXR and this may indicate that nonphagocytic circulating monocytes may be more important in DXR. However, adoptive transfer of splenocytes from a macrophage depleted, xenoactivated donor did not accelerate xenograft rejection, while splenocytes from a nondepleted xenoactivated donor did, thereby supporting the importance of monocytes and macrophages in this I phase of xenograft rejection.     

Characterization,quantification, and localization of passenger T lymphocytes and NK cells in human liver before transplantation

Quantification and localization of the main lymphocyte populations were studied in the livers of normal (n=8) and brain dead (n=8) subjects. Cytometric analysis performed on mononuclear cell suspensions obtained from liver biopsies was compared to an automatic image analysis of immunostained sections. The overall number of liver associated lymphocytes was in the usual range of peripheral blood content (2 to 9 · 10⁹ cells). Phenotypic analysis showed predominant NK and CD8+ cells that highly expressed class II antigen and CD25 and CD69 activation markers. Quantitative mapping of these activated lymphocytes revealed their preferential localization in the portal tract and the perisinusoidal area as compared to the pericentrolobular zone, especially in donor livers. This strategic localization could suggest a possible early cooperation between donor lymphocytes and initial infiltrating cells from the recipient and could explain the special immunological status of allografted livers.     

慢性乙型肝炎病毒感染者外周血T细胞亚群及NK细胞的特点及意义

目的探讨慢性乙型肝炎病毒（hepatitis B virus,HBV）感染者外周血T细胞亚群及NK细胞的特点及临床意义。方法采用流式细胞术检测各研究组,包括慢性乙型肝炎（chronic hepatitis B,CHB）组33例、乙型肝炎失代偿期肝硬化（1iver cirrhosis,LC）组20例、慢性乙型重型肝炎（chronic severe hepatitis B,CSH）组17例及健康对照组（Control）20例的外周血T细胞亚群及NK细胞相对计数,并检测肝功能、HBVDNA含量及HBV血清标志物。结果按Control、CHB、LC、CSH顺序,CD3^＋T细胞、CD8^＋T细胞百分比依次升高,而CIM^＋T细胞、CD4^＋／CD8^＋比值及NK细胞百分比依次降低,且CHB、LC、CSH组与Control组及CHB组与CSH组相比,差异均有统计学意义（P〈0．05或P〈0．008）。CHB患者的CD3^＋T细胞与血清总胆红素（total bilirubin,TB）、HBVDNA含量（log_10）呈正相关（P〈0．001;P〈0．001）;CD8^＋T细胞与HBVDNA含量（log_10）呈正相关（P=0．007）,NK细胞与HBVDNA含量（log_10）（P=0．001）呈负相关。CHB组乙型肝炎e抗原（HBeAg）阳性者的CD4^＋T细胞及CD4^＋／CD8^＋比值低于HBeAg阴性者（P=0．018;P〈0．001）,而HBVDNA含量（log_10）和CD8^＋T细胞高于HBeAg阴性者（P=0．012;P=0．019）。结论慢性HBV感染者外周血T细胞亚群及NK细胞相对值紊乱,且与临床类型、病情、血清HBVDNA水平及HBeAg相关。     

CD4+T细胞ATP含量与肝移植后急性排斥反应的关系

目的 探讨CD4+T细胞ATP含量与肝移植术后围手术期急性排斥反应(acute rejection,AR)的关系.方法 以2009年2月至2009年10月在本院行肝移植术的77例病人为研究对象.肝移植病人术前以及术后1、2、4周各采集1份全血标本,发生AR当日和激素冲击治疗后1周各采集1份全血标本.每次均送检1～2份健康志愿者全血标本作为对照.用ImmuKnowTM免疫细胞功能测定试剂盒检测样本中CD4+T细胞ATP值.结果 AR组病人ATP值在术后第1周达到高峰,显著高于同期非排斥组.术后第1周的高ATP值对诊断肝移植术后围手术期AR具有较好的敏感度和特异度.AR组病人排斥当日的ATP值与排斥活动指数(RAI)呈显著正相关,经激素冲击治疗1周后,AR均达到逆转,ATP值明显降低.结论 肝移植术后围手术期,CD4+T细胞ATP值动态变化与移植肝急性排斥反应密切相关,有望成为诊断和预防围手术期AR发生以及抗排斥治疗效果的无创监测指标.     

肝移植术后潜在免疫耐受者外周血自然杀伤细胞、调节性T细胞和记忆性T细胞的表达及其临床意义

目的 探讨肝移植术后潜在免疫耐受者免疫状态,为临床指导抗排斥治疗提供依据.方法 纳入1999年1月至2007年12月在本中心行肝移植存活至今潜在免疫耐受者29例,分为3～5年组(3Y组)10例,5～11年组(5Y组)19例,另纳入肝移植术后反复排斥反应者(RJ)10例,年龄匹配健康对照组(HC)17例;流式检测外周血单个核细胞中自然杀伤(NK)细胞、记忆性T细胞、调节性T细胞(Treg)3个亚群的表达.结果 3Y、5Y组CD4+ CD25+T细胞(3Y:27.56±4.63;5Y:30.07±3.91)、静息性Treg占CD4+T细胞比例(3Y:0.22±0.05;5Y:0.17±0.03)比R J组明显升高(CD4+ CD25+ T:11.78±4.28;静息性Treg:0.05±0.02)(P＜0.05);5Y组NK细胞占淋巴细胞比例(29.11±3.31)比RJ组(13.92±3.11)明显升高(P＜0.05);效应性记忆性CD8+T细胞比例3Y组(12.92±2.05)比RJ组(8.74±1.69)明显升高(P＜0.05).结论 肝移植术后潜在免疫耐受者外周血NK细胞、静息性调节性T细胞和效应性记忆性CD8+T细胞比例相对排斥反应者明显升高,可作为潜在的耐受标志物.     

猕猴组织工程化骨异体植入修复骨缺损T淋巴细胞亚群的检测

目的　通过对T淋巴细胞亚群的检测 ,从免疫学方面探讨同种异体细胞来源的组织工程化骨植入猕猴体内修复长段骨缺损的可行性。方法　用骨髓基质干细胞 (MSCs)经诱导分化为成骨样细胞后与生物衍生骨材料复合培养 ,体外构建组织工程化骨 ,植入 15只异体猕猴体内桥接桡骨 2 .5cm节段骨缺损作为实验组 ;用单纯生物衍生骨材料桥接对侧同样大小骨缺损作为对照组 ;分别于术后 1、2、3、6、12周抽取静脉血和作双侧局部组织取材 ,样本应用流式细胞术检测T淋巴细胞亚群CD3 /CD4 /CD45 、CD3 /CD8 /CD45 和CD2 8 阳性率。结果　术后第 1、2、3、6、12周实验组和对照组T淋巴细胞亚群CD3 /CD4 /CD45 、CD3 /CD8 /CD45 和CD2 8 阳性率两者差异均无显著性 (P >0 .0 5 )。结论　生物衍生骨材料和猕猴MSCs复合构建组织工程化骨植入异体猕猴体内其术后 12周内免疫反应水平低 ,可用以修复猕猴节段骨缺损。     

Role of NK and NKT cells in solid organ transplantation

In the context of solid organ transplantation, the exact interactions between the innate and adaptive alloimmune response have not yet been fully explored. In this transplant setting, natural killer (NK) cells have emerged as a particular focus of interest because of their ability to distinguish allogeneic major histocompatibility complex (MHC) antigens and their potent cytolytic activity. Based on this observation and its potential clinical relevance, NK cells have recently been shown to participate in the immune response in both acute and chronic rejection of solid organ allografts. Numerous experimental and clinical studies demonstrate that NK cells determine transplant survival by rejecting an allograft not directly but indirectly by providing bystander effects. In addition, NK cells are influenced by immunosuppressive therapies such as calcineurin inhibitors or steroids. As NK and natural killer T (NKT) cells have also been shown to play a profound role in allograft tolerance induction, this review summarizes the major findings to highlight the functional role of these lymphocyte subsets, which may constitute an underestimated mechanism affecting graft outcome in solid organ transplantation.