异种肝移植急性排斥反应中细胞凋亡的研究

目的 观察肝移植急性排斥反应中移植肝细胞凋亡，并初步探讨其分子机制。方法 三袖套法建立肝移植急性排斥应模型，普通组织及原位末端标记法检测移植中细胞凋亡，免疫组织化学方法检测移植肝中Fas-L，TGF-β1的表达。结果 在肝移植急性排斥反应中，移植肝出现细胞凋亡，并表达Fas-L、TGF-β1，随着肝移植急性排斥反应的加重，其细胞凋亡增多，Fas-L,TGF-β1表达增高。结论的细胞凋亡作为细胞死亡的一种机制，存在于肝移植急性排斥反应中，其机制与Fas-L,TGF-β1有关，可作为判断肝移植免疫排斥反应的指标。     

供体骨髓间充质干细胞干预非协调性异种肝移植免疫排斥反应的实验研究

目的研究骨髓间充质干细胞(MSCs)对非协调性异种肝移植排斥反应的免疫干预作用。方法密度梯度离心法分离培养豚鼠MSCs,流式细胞仪检测其膜表面CD34、CD45、CD44和CD29的表达,脂肪细胞诱导液培养诱导MSCs向脂肪细胞分化。豚鼠MSCs输注大鼠后检测不同时相免疫球蛋白IgG、IgM、IgA以及补体C3、C4的浓度变化。豚鼠和大鼠各30只随机分为3组,所有大鼠受体经环磷酰胺预处理,A组为MSCs输注组;B组为生理盐水输注组;C组为地塞米松输注组。各组行豚鼠大鼠原位肝脏移植手术,观察受体的存活情况及排斥反应情况。结果MSCs膜表面CD34阴性、CD45阴性、CD44阳性、CD29阳性。脂肪细胞诱导液培养后细胞内出现脂滴沉着。MSCs细胞悬液输注受体后各个时相的免疫球蛋白IgG、IgM和补体C3较输注前有显著降低(P<0.01),而IgA和补体C4与输注前相比无明显变化(P>0.05),输注后的免疫球蛋白IgG、IgM和补体C3各个时相点之间的浓度变化无显著差异(P>0.05)。肝脏移植模型A组受体存活时间为(431±27)min,较B组和C组的存活时间[(148±16)min、(141±22)min]显著延长(P<0.01)。A组受体超急性排斥反应发生较迟,程度轻。结论MSCs的鉴定可根据细胞形态,膜表面标志物和分化能力来确定,MSCs可干预异种肝脏移植的超急性排斥反应的发生。     

细胞毒T淋巴细胞在异种肝移植急性排斥反应中的作用

目的：探讨异种肝移植中细胞毒T淋巴细胞（CTL）参与急性排斥反应的机制。方法：三袖套法建立仓鼠到大鼠原位肝移植模型；免疫组化方法检测同基因组与异种移植组（XT组）移植肝术后CD8和CD4型淋巴细胞浸润及Fas-L，穿孔素的表达情况，并运用原位末端标记法检测移植肝细胞的凋亡情况。结果：XT组移植肝术后第2d汇管区出现淋巴细胞浸润，逐日增多，至术后5－6d达高峰；术后第4d穿孔素及Fas-L开始表达，术后第5－6d达高峰；穿孔素的表达始终高于Fas-L。结论：异种肝移植中T淋巴细胞参与了其免疫排斥反应，通过表达穿孔素或Fas-L使靶细胞坏死或凋亡。     

细胞免疫在异种肝移植免疫排斥反应中作用的研究

目的观察细胞免疫在异种肝移植急性排斥反应中的作用,并初步探讨其分子机制。方法建立仓鼠到大鼠原位肝移植模型,运用切脾、环磷酸胺、环孢霉素Ａ处理受体,观察其对生存时间影响,并运用免疫组织化学方法检测移植肝中淋巴细胞的浸润情况及穿孔素、Ｆａｓ－Ｌ的表达。结果异种肝移植术后受体必须同时加用抑制细胞免疫抑制剂环孢霉素Ａ方可延长其生存时间,免疫排斥反应发生时移植肝中可见大量的淋巴细胞浸润,及穿孔素和Ｆａｓ－Ｌ的表达。结论细胞免疫参与了异种肝移植免疫排斥反应,其作用与穿孔素、Ｆａｓ一Ｌ的表达密切相关。     

异种移植的细胞免疫排斥反应

现代外科技术和免疫抑制治疗的发展,使同种器官移植受体的存活时间越来越长,而供体短缺成为阻碍同种移植发展的首要难题.开展异种移植研究,用来源广泛且功能完备的动物器官代替人体器官进行移植治疗,是解决供体短缺的有效方法[1].猪的繁殖速度快,各项生理指标与人类近似,且伦理学争论较小,因而目前大多数研究者倾向将小型猪作为异种器官移植研究的供体[2].然而,以猪作为供体的异种移植术后存在免疫排斥反应、生理屏障及潜在交叉感染三大问题,其中免疫排斥反应是目前困扰异种器官移植发展的最主要问题.随着α-1,3-半乳糖基转移酶基因敲除猪和转染人补体调节蛋白编码基因小型猪的成功克隆,异种移植的超急性排斥反应已基本解决,但以细胞免疫应答为主的急性排斥反应仍是异种器官移植应用于临床之前必须克服的免疫障碍.参与异种急性排斥反应的免疫细胞种类繁多,发生机制复杂,目前尚缺乏有效的防治手段.本文就异种急性细胞排斥反应的研究进展进行评述,希望为异种器官移植的临床研究提供参考.     

克服异种移植免疫排斥的研究进展

目的 综述克服异种移植免疫排斥的方法.方法 广泛查阅近年国内外克服异种移植免疫排斥的相关文献,并进行总结与分析.结果 目前对异种移植免疫排斥机制和分子生物学技术的研究,为解决异种移植免疫排斥提供了新的思路.结论 异种器官移植应用于临床仅是时间问题.     

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。     

异种肝移植中补体作用及抑制策略

近 40年来 ,随着同种肝移植的巨大成功 ,供肝短缺的问题日益突出。异种移植作为较有希望的解决途径之一 ,得到越来越多的重视。但阻碍异种肝移植临床实施的首要障碍即是超急性排斥反应 (ＨＡＲ)。大量的研究表明 ,补体在ＨＡＲ发生中起着重要作用 ;而抑制补体激活可以阻止ＨＡＲ ,尤其是转人补体调节蛋白 (ｈＣＲＰ)基因的动物的出现 ,更使人们看到了征服ＨＡＲ的光明前景。这里 ,将近年补体在异种肝移植中超急性排斥反应中的作用及其防治策略的进展作一综述。一、补体在超急性排斥反应发生中的作用及激活途径1.补体在超急性排斥反应发生中…     

脾脏在小鼠同种肝移植排斥反应中的作用

目的 观察脾切除在小鼠同种肝移植急性排斥反应过程中的作用.方法 双袖套法建立小鼠原位肝移植模型,随机分为3组,即建模保留脾脏组、建模3 d后切除脾脏与建模同时切除脾脏组,各组于移植术后14 d处死,ELESA法测定血清IgM水平;肝功能检测采用速率法;流式细胞仪检测CD4与CD8T细胞亚群;并同时行肝脏及脾脏的病理形态观察.结果 建模保留脾脏组、建模3 d后切除脾脏与建模同时切除脾脏组血清IgM水平分别为3.0181±0.4627、3.0936±0.4559、3.1953±0.4449,各组间差异无统计学意义(P＞0.05);ALT水平分别为108.6875±20.3657、83.0000±22.7799、76.8000±19.5784,差异有统计学意义(P＜0.05);AST水平分别为:105.3750±29.0583、93.0000±22.7799、93.2000±33.4220,各组间差异无统计学意义(P＞0.05);CD46+/CD8+T细胞分别为:1.9162±0.2778、1.5654±0.4750、1.4616±0.2762,差异有统计学意义(P＞0.05);3组肝脏间质及汇管区淋巴细胞浸润程度依次减弱,供肝灶状坏死程度逐渐减轻,在保留脾脏组中建模后第14天脾脏边缘区及淋巴鞘较建模同时切除的脾脏增宽.结论 在小鼠同种异体肝移植排斥反应中细胞免疫起主要作用,脾切除可部分抑制同种异体肝移植急性排斥反应,保护供体肝脏.     

异种移植免疫排斥的研究进展

异种移植是解决人体器官严重短缺的重要思路.随着对异种移植排斥和人畜共患感染性疾病的深入研究,以及α-1,3-半乳糖苷转移酶基因敲除猪的成功构建,以猪为供体的异种移植与临床应用之间的距离正在逐渐缩短.阻碍异种移植发展的主要障碍仍是免疫排斥反应.本文试就目前异种免疫排斥的研究进展进行综述,希望对未来的临床异种移植研究提供参...     

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.     

Mechanisms of hyperacute rejection of discordant liver xenograft

Abstract: Use of discordant liver xenografts is a possible means of overcoming the ever-increasing organ shortage. Immunological barriers, however, remain the major obstacle to the application of this therapeutic option. The aim of the study was to establish the model and to further investigate mechanisms of hitherto assumed liver xenograft rejection in the discordant guinea pig to rat combination and to determine the role of complement activation in this model.
Male guinea pigs served as donors, and all recipient Lewis rats underwent splenectomy prior to orthotopic liver transplantation with a modified cuff technique. Animals were grouped according to their pharmacologic therapy: group 1: control group, no further therapy; group 2: plasmapheresis immediately prior to transplantation; group 3: Cobra venom factor; group 4: plasmapheresis and Cobra venom factor; group 5: Cyclosporin A; and group 6: RS 61443 with three animals in each group. Median survival was 62 (52–68) minutes in group 1, 150 (129–190) in group 2, 745 (260–1034) in group 3, 45 (18–60) in group 4, 91 (76–118) in group 5, and 212 (170–245) in group 6. Histologically, portal and sinusoidal congestion, interstitial haemorrhages, intragraft granulocyte deposits, and parenchymal damage were found to be most pronounced in groups 1 and 3. In all groups endothelial cells stained positive for IgM and complement component C3 compatible with classical pathway activation. From our findings where deposition of Factor H was noted it is concluded that in this discordant model the complement system is activated by the alternative pathway. Intragraft IgM deposits, however, suggest that the classical activation pathway may also be involved.     

Infusion of donor spleen cells and rejection in liver transplant recipients

Intact or inactivated donor lymphoid cells have been found to downregulate the alloimmune response in a number of experimental models. We conducted a randomized, prospective, double blind, and placebo-controlled trial to determine whether heat-treated donor spleen cells would affect early rejection after liver transplantation. Donor spleen was obtained during organ procurement for 40 patients undergoing liver transplantation. All patients were treated with cyclosporine, azathioprine and steroids. The patients were randomized after surgery to receive either heat-treated (45 degrees C for 1 h) spleen cells or placebo. Patients underwent protocol biopsies at 1 wk, 4 and 12 months, or as needed. Biopsies were reviewed in a blind fashion and scored according to the Banff consensus criteria. Randomization resulted in 19 patients in the spleen cell group and 21 in the placebo group. One-yr graft survival was 94 and 100%, respectively. Early rejection was more frequent in the spleen cell group (61 vs. 35%, p, not significant). The histopathological rejection activity index at 7 d was also higher for the patients in the spleen cell group: 39% of spleen cell treated patients had a score of 4 or higher as opposed to 5% in the placebo group (p < 0.01). The mean score was 2.9 +/- 2.8 for the spleen cell group versus 1.3 + 1.7 for the placebo group (p = 0.034). It is concluded that heat-treated donor spleen cells given within 24 h after liver transplantation were not clinically beneficial and increased the intensity of rejection in 7-d protocol liver biopsies.     

老年结直肠癌手术前后免疫功能的变化

目的　探讨老年结直肠癌病人手术前后免疫状况的变化。方法　对我院 6 0岁以上行根治性手术的 6 8例结直肠癌病人进行手术前后细胞免疫和体液免疫的检测 ,并将之与健康老年对照组和年轻结直肠癌病例进行比较。结果　老年结直肠癌病人手术前CD4、CD4 /CD8和NK细胞水平低于健康老年人群和年轻病人 ,而CD8、TNF α和SIL 2R水平较健康老年人群和年轻病人明显增高。手术后 2周年轻病人的CD4、CD4 /CD8和NK细胞水平较手术前升高 ,CD8、TNF α和SIL 2R水平降低 ;而老年病人除TNF α和SIL 2R水平显著降低外 ,各项免疫学指标无显著变化。老年结直肠癌病人手术前IgM、IgA和IgG水平低于健康老年人群。手术后 2周年轻病人的IgM、IgA、C3 和C4水平增高 ,而老年病人较术前无变化。结论　针对老年病人的免疫特点 ,加强围手术期处理 ,改善老人的营养情况 ,必要时结合有效的生物治疗 ,及时提高病人的免疫功能 ,预防术后肿瘤复发     

骨折与手术对机体免疫功能的影响

通过对４１例创伤性骨折患者在骨折及手术后不同时间进行细胞免疫及体液免疫测定，发现骨折后６天的免疫水平明显高于骨折后３天的免疫水平，手术后７２小时的免疫水平明显高于术后９０分钟的免疫水平。由此可知，机体免疫水平与创伤骨折及手术密切相关。这项研究也为感染的解释及免疫防治提供依据。     

B细胞介导的体液免疫应答在肝移植急性排斥反应中的作用

目前，国内外肝移植学界对肝移植术后急性排斥反应(AR)的机制阐释为T细胞介导的细胞免疫应答，但为获得长期生存仍需长期乃至终身服用免疫抑制剂。即使如此，临床上AR仍时有发生，并导致相当一部分受者移植肝功能丧失，更重要的是受者术后还受到感染、肿瘤和其他一系列不良反应及沉重经济负担的影响。因此，为肝移植AR机制提出新的理论解释，更全面深入阐明肝移植免疫排斥反应的内在机制，进而依据新的机制研制出新型免疫抑制剂已势在必行。本文就B细胞介导的体液免疫应答在肝移植AR中的作用作一综述。