同基因造血干细胞移植免疫重建诱导小鼠皮肤移植耐受

背景：器官移植耐受的最佳效果是能够诱导对移植抗原的特异性免疫耐受。 目的：探讨小鼠异基因皮肤移植后,通过受体同基因造血干细胞移植重建免疫系统诱导移植皮肤免疫耐受的可行性。 方法：取BALB/c小鼠骨髓。以C57BL/6小鼠为供体,BALB/c小鼠为受体,进行异基因皮肤移植;32只受体鼠随机均分为4组：移植对照组、环孢素A组、照射组和骨髓移植组。 结果与结论：照射组小鼠10 d内全部死亡,外周血白细胞数呈持续性降低;而骨髓移植组小鼠长期存活,白细胞数全身照射后6 d降到最低,之后持续性增高,照射后21 d与环孢素A组比较差异无显著性意义(P > 0.05),移植皮肤存活时间显著长于其他各组(P < 0.01),其淋巴细胞浸润及组织结构破坏明显减少,小鼠脾细胞对供体小鼠脾细胞增殖反应显著降低。说明同基因骨髓细胞移植重建免疫系统可显著延长小鼠移植皮肤存活时间,可诱导供者特异性免疫耐受。     

雷公藤延长小鼠同种皮肤移植物存活时间

在对同种器官移植排斥反应的予防和治疗中,尽管采用了组织配型,移植前输血及抗淋巴细胞球蛋白等较为有效的方法,仍需使用肾上腺皮质激素、硫唑嘌呤等免疫抑制剂。由于这些药物的毒副作用十分严重,故寻找有效、低毒的排斥反应抑制药物依然是移植免疫学的重要课题之一。李乐真等报告了雷公藤提取物防治大鼠佐剂性关节炎,临床用于原发性肾小球疾患以及系统性红斑狼疮等自身免疫性疾患的治疗取得了令人满意的疗效。这些提示     

CD200基因重组质粒延长异基因小鼠皮肤移植物存活的实验研究

目的:利用小鼠同种异体皮肤移植模型,观察重组基因CD200的抗排斥作用。方法:用肌肉注射并电转染的方法,将pcDNA3-CD200基因重组质粒100μg转染到受者BALB/c小鼠体内,同日进行皮肤移植,记录移植皮片的存活时间,采用RT-PCR和免疫荧光的方法检测CD200基因在受者体内的转录和表达,用HE染色观察移植皮片组织病理改变情况。用MTT法检测受鼠对供鼠及第三方供鼠的单向混合淋巴细胞反应(MLR)。结果:RT-PCR和免疫荧光检测表明,肌肉注射并电转染pcDNA3-CD200基因重组质粒后,可在肌肉组织中检测到CD200基因的转录和表达。空白对照组移植皮片平均存活时间为(8·67±1·75)天,pcDNA3空质粒组移植皮片平均存活时间为(8·00±1·55)天,pcDNA3-CD200组小鼠移植皮片平均存活时间为(11·78±1·86)天,移植皮片的存活时间显著延长(P<0·05);pcDNA3-CD200组移植皮片内浸润的炎细胞数量明显减少;MLR检测表明pcDNA3-CD200组的BALB/c小鼠对C57BL/6供鼠的MLR明显低于空白对照组(15天时0·11±0·02低于0·19±0·03,P<0·05),对第三供鼠的MLR也相似。结论:肌肉注射并电转染pcDNA3-CD200基因重组质粒可在小鼠体内大量转录和表达并延长了皮肤移植物的存活时间,减少移植物内炎细胞浸润,降低混合淋巴细胞反应,具有显著的抗排斥作用。     

髓腔内骨髓移植诱导异基因小鼠皮肤移植耐受的研究

探讨髓腔内骨髓移植(IBM-BMT)对异基因小鼠皮肤移植耐受的诱导效果。受鼠为雌性C57BL/6(H-2b,B6)小鼠,于第0天接受60Coγ射线全身照射(TBI),4 h内输注雄性BALB/c(H-2d)小鼠来源的骨髓细胞(BMC),2 d后腹腔注射环磷酰胺(CTX)。通过皮肤移植、混合淋巴细胞反应(MLR)检测耐受状态,并通过骨髓染色体分析了解BMC的植入程度。结果显示,接受IBM-BMT的B6小鼠对BALB/c小鼠的皮肤移植物平均存活时间(MST)超过300 d,显著长于其余两组(P<0.001);MLR结果证明,实验组B6小鼠获得供体特异性耐受,在耐受小鼠骨髓中可检测到一定比例的Y染色体存在。以上表明髓腔内骨髓移植可以保证异基因骨髓细胞的植入并形成混合嵌合状态,从而有效地诱导免疫耐受。     

CTLA-4Ig联合髓腔内骨髓移植诱导小鼠同种异体皮肤移植耐受的研究

目的探讨细胞毒性T淋巴细胞相关抗原4免疫球蛋白(Cytotoxic T Lymphocyte Antigen4-immunoglobulin,CTLA4-Ig)与髓腔内骨髓移植(IBM-BMT)联合应用对诱导供体小鼠皮肤移植免疫耐受的促进bd作用。方法受鼠为C57BL/6(H-2,B6)雌性小鼠,于第0天输注雄性BALB/c(2)小鼠来源的骨髓细胞(BMC),同时腹腔注射CTLA4-Ig;第6天进行皮肤移植,并于移植术后第2天再进行一次腹腔注射CTLA4-Ig,观察皮肤移植物存活时间。通过皮肤移植物的组织学分析,以及混合淋巴细胞反应(MLR)检测耐受状态,并通过骨髓染色体分析了解BMT的植入程度。结果联合治疗组B6小鼠的皮肤移植物平均存活时间(MST)显著长于其它各组(P<0.05);MLR结果证明,联合组B6小鼠获得供体特异性耐受,在耐受小鼠骨髓中可检测到一定比例的Y染色体存在。结论 CTLA4-Ig与髓腔内骨髓移植可保证异基因的骨髓细胞形成嵌合体,显著延长了移植物存活时间,诱导免疫耐受。     

异基因造血干细胞移植后的移植物抗白血病作用的临床观察

移植物抗白血病作用（GVL）是异基因造血干细胞移植后,引起造血系统肿瘤持续缓解状态的一种免疫介导的反应。目前,对GVL的机理仍不清楚。临床上观察到,在GVL出现前,病人多经历了一个急或慢性的移植物抗宿主病（GVHD）过程。GVHD使受者正常的组织和细胞受到损伤,而同时产生     

基质细胞与造血干细胞移植后的造血重建

造血干细胞移植作为造血损伤修复及血液病治疗的主要手段已日益受到重视。受体的造血系统重建取决于两个条件：一是造血干细胞的质量和数量,二是造血微环境的质量。１９７７年,Ｄｅｘｔｅｒ用小鼠骨髓细胞进行长期培养,发现造血细胞只有附着于一种被称为基质细胞的集落上,才能增殖。而后 Ｍａｕｃｈ等［１］继而在人骨髓细胞长期培养的实验中证实了这一点。可以认为造血干细胞在分化增殖需要有一个特殊的环境,即造血微环境。基质细胞是造血微环境的主要成分,具有支持造血的作用。 一、基质细胞 造血微环境（ｈｅｍａｔｏｐｏｉｅｔｉ…     

清肿瘤性异基因造血干细胞移植

标准的清髓性异基因造血干细胞移植(allo-HSCT)对于需代替治疗的造血与免疫系统的非恶性疾病,应当是合理或足够的;然而,对于恶性血液病患者,清除患者骨髓造血组织,成功重建异体正常造血与免疫系统,并不一定能完全治愈恶性血液病,因为白血病(干)细胞并非只限骨髓中存在,它可浸润骨髓之外的其他任何组织。临床实践证实,allo-HSCT后仍然有30%左右的患者疾病复发,特别是具有高危因素或难治复发患者复发率可高达40%～70%以上。这些复发的白血病细胞几乎全系源自患者移植前本身的白血病细胞,其中半数患者以髓外部位复发开始,有证据提示,清髓性移植并没有完全杀灭患者体内的白血病细胞,特别是那些对化放疗不敏感或栖居在髓外"庇护所"中的白血病干细胞,最终导致疾病复发。因此笔者提出并建立了一个清肿瘤性异体造血干细胞移植(TAHSCT)的概念,在临床上对其进行了初步的探讨。其内容贯穿于移植技术全过程的各个环节,但主要为应用个体化清肿瘤性预处理方案和加强移植后免疫治疗。     

自体造血干细胞移植在白血病的应用

自体造血干细胞移植（Auto—HSCT）是将患者的自身造血干细胞采集出来,进行或不进行特殊处理后再回输到经过超大剂量放疗和（或）化疗处理后的患者体内,使其造血和免疫功能得以恢复重建。依据移植中回输的造血干细胞来源,可分为自体骨髓移植（ABMT）、自体外周血造血干细胞移植（APBSCT）和自体脐带血移植（ACBT）。     

树突状细胞和造血干细胞移植的研究进展

树突状细胞(DC)是功能最强的抗原递呈细胞(APC),在移植免疫中,DC启动免疫排斥还是维持免疫耐受取决它们的起源以及成熟状态,成熟DC启动免疫排斥及移植物抗宿主病(GVHD)反应,未成熟(iDC)及淋巴样DC诱导免疫耐受。造血干细胞移植(HSCT)中,可以通过调控不同来源、不同分化状态的DC来预防和治疗移植物抗宿主病(GVHD),促进造血干细胞的植入。     

Prolongation of skin allograft survival in rats by the transplantation of microencapsulated xenogeneic neonatal porcine Sertoli cells

Skin rejection remains a major hurdle in skin reconstructive transplantation surgery. In fact, 85% of the grafted patients experience at least one episode of acute skin rejection in the first year. It has been observed that Sertoli cells (SC), when co-transplanted with allo- or xenogeneic cell/tissues, can induce graft acceptance in the absence of systemic immunosuppression. A method aimed at significantly prolonging skin allografts in rats transplanted with barium alginate-based microencapsulated xenogeneic porcine SC (SC-MCs) is described. Results demonstrated that intraperitoneal (IP) transplantation of SC-MCs with high cellular viability and function can significantly prolong allogeneic skin grafts when compared to transplantation controls receiving only empty alginate capsules (E-MCs). Lymphocytic infiltration at the skin graft site was not observed in 80% of the SC-MCs transplanted rats and these recipient animals showed a significant increased expression of T regulatory (Tregs) cells when compared to E-MCs transplantation controls. The findings of this report further substantiate the positive therapeutic effects of SC on transplantation technology mediated by Sertoli cell-induced alterations of the host's immune system and indicate new perspectives and new strategies for successful skin tissue allografts.     

抗B7-1和抗CD40L单抗延长小鼠皮肤移植物存活实验研究

将C57BL/6小鼠腹部全层皮肤移植于BALB/c小鼠中段背部,实验分组(每组7只小鼠):1.B7-1功能性单抗(4E5)治疗组;2.抗CD40L单抗(4F1)治疗组;3.4E5+4F1治疗组,各单抗以20㎎/㎏的剂量注入腹腔内;4.空白对照组,只注射同等量的生理盐水。注射时间为移植后0﹑1﹑3﹑5d,观察移植皮肤排斥情况。于术后第6天分别杀死各组受体和供体鼠,取受体脾细胞与供体作混合淋巴细胞反应(MLR)。收集培养6d的初次反应细胞,检测再次MLR。结果发现,与对照组相比,各单抗治疗组皮肤移植物存活时间延长(P<0.05﹚;与各单独应用4F1和4E5相比,联合使用4F1和4E5产生一定的协同作用,但未能进一步延长移植物的寿命(P>0.05)。初次单向MLR:4F1﹑4E5和4F1+4E5治疗组受体T淋巴细胞在MLR中表现对供体淋巴细胞特异性低反应性,能有效抑制T细胞对同种异体抗原的初次应答。再次单向MLR:4F1﹑4E5﹑4F1+4E5对供体淋巴细胞在再次反应中仍保持着对同种抗原的反应性,与对照组无显著差异,未能诱导特异性免疫耐受。综上结果证实,anti-CDB7-1mAb(4E5)和anti-CD40LmAb(4F1)作为新型免疫抑制剂,在一定程度上抑制细胞免疫应答,干预排斥反应。     

Optimistic expectations and survival after hematopoietic stem cell transplantation.

An optimistic attitude is hypothesized to be beneficial when facing a life-threatening medical condition. However, the actual relationship of high expectations for treatment success and medical outcome is controversial. Using a prospective cohort of 313 autologous and allogeneic hematopoietic stem cell transplant patients enrolled July 1996 through November 1999, we tested whether patient-reported expectations before transplantation were associated with survival and quality of life following the procedure. Before transplantation, patients with higher expectations that the transplant procedure would go well had better mental and emotional functioning, but similar physical status and medical condition to patients with less optimistic expectations. In the first 2 months after transplantation, optimistic expectations were associated with better survival (92% v 84%; relative risk for mortality 0.45, 95% confidence interval 0.22-0.92; P=.03) controlling for other physical and mental characteristics. However, by 6 months posttransplantation, survival and quality of life were indistinguishable between patients with initially higher and lower expectations. Our data suggest an association between more optimistic expectations and early survival following hematopoietic stem cell transplantation, but this association is not present by 6 months posttransplantation.     

Immunogenomics of hematopoietic stem cell transplantation

Recipients of allogeneic hematopoietic stem cell transplantation (HSCT) incur the risk of graft-versus-host disease even when the donor is a sibling who shares the Major Histocompatibility Antigens. Therefore, even the perfect HLA match does not represent the optimal genetic match between donors and recipients in HSCT. In addition to the HLA complex other genetic systems operate and affect the outcome of HSCT. These include minor histocompatibility systems (Martin P. Applicability of matching for minor histocompatibility antigens in human bone marrow transplantation. In: Roopenian DC, Simpson E, editors. Minor histocompatibility antigens: From the laboratory to the clinic. Georgetown: Landis Bioscience; 2000. p. 97-103) (inducing bona fide allogeneic responses) as well as a series of functional polymorphisms in cytokines and chemokines and receptors genes (Transplantation 1997;64:553). Among the items affecting the outcome of HSCT the incidence and severity of infections have an important impact. Polymorphisms of genes controlling both arms of the immune responses to pathogens (innate versus cognate) are strong candidates for susceptibility factors to infection in allogeneic transplantation. These include the MHC alleles (HLA class I, class II, MIC) CD1, Toll and TLR genes MBP, MPO genes, ...). In addition to the NK alloreactivity induced by HLA class I epitopes mismatching (a common situation in HSCT) variations in the genotype of the KIR genes (Tissue Antigens 2001;57:358) may also be encountered between the donor and the recipient leading to potentially harmful or beneficial combinations. An integrated knowledge of the role and hierarchy of the most important genetic factors (MHC and non-MHC) will provide the rationale for a comprehensive matching in HSCT (Curr Opin Hematol 3 (1996) 416). This short review provides a panorama of this strategic issue for further development of HSCT.     

HLA-E polymorphisms in hematopoietic stem cell transplantation

Human leukocyte antigen (HLA)-E is an inhibitory ligand of natural killer cells and γ/δ T-cells. Differential expression of HLA-E alleles on the cell surface has been reported to influence outcome of hematopoietic stem cell transplantation (HSCT). We performed HLA-E genotyping in 116 HSCT patients and their HLA-matched unrelated donors. The impact of HLA-E genotypes on patient's overall survival (OS), disease free survival (DFS), cumulative incidences for relapse, transplant-related mortality (TRM) and acute graft vs host disease (aGvHD) was assessed. Neither univariate nor multivariate analysis showed any influence of HLA-E polymorphisms on the investigated endpoints of HSCT in our cohort. We could not confirm any of the previous observations in our cohort and consider it unlikely that HLA-E polymorphisms affect outcome of HSCT.     

Reimmunization after hematopoietic stem cell transplantation

Hematopoietic stem cell transplant recipients lose immune memory of exposure to infectious agents and vaccines accumulated through a lifetime, and therefore need to be revaccinated. Reimmunization protocols vary greatly among hematopoietic stem cell transplant centers. Diphtheria and tetanus toxoids, pertussis vaccine, Haemophilus influenza type B conjugate, 23-valent pneumococcal polysaccharide, inactivated influenza and polio vaccine and live attenuated measles-mumps-rubella vaccine are the currently recommended vaccines to be included in a vaccination program after hematopoietic stem cell transplant. Other variables, such as stem cell source, new adjuvants, T-cell depleted transplants, nonmyeloablative conditioning and donor immunization have recently been introduced and a constant update of current recommendations are needed. Studies recently published, the use of other vaccines and the perspectives for different vaccination protocols are discussed in this review.     

KIR matching in hematopoietic stem cell transplantation

Although the key role of MHC-restricted T lymphocytes in hematopoietic stem cell transplantation (HSCT) has been known for a long time, recent data have focused on complementary or alternative effector cell populations, and in particular on NK cells. Spontaneously generated NK cell alloreactivity from stem cell grafts involves specific interactions between NK receptors, including killer immunoglobulin-like receptors (KIRs) and their MHC class I ligands. The combined effects of HLA and KIR polymorphic genes might explain discrepancies in the impact of donor-recipient matching observed in HSCT.