双重膜滤过式血浆置换清除肾移植受者供体特异性抗体的临床观察

目的探讨双重膜滤过式血浆置换(DFPP)对高致敏肾移植受者的供体特异性抗体(DSA)的清除效果。方法 4例肾移植高致敏受者共进行了7例次DFPP治疗,采用Luminex技术监测DSA的变化,观察治疗效果、急性排斥反应发生情况及其不良反应。结果治疗后DSA的MFI[1 036(0~4 113)]较治疗前[6 446(2 999~12 905)]明显下降(Z=-2.503,P=0.012)。4例高致敏肾移植受者均未发生超急性排斥反应,仅有1例发生急性排斥反应且通过术后DFPP治疗及调整免疫抑制剂得到逆转。受者随访至今移植肾功能良好,未发生排斥反应。DFPP治疗引起白蛋白水平下降。结论 DFPP可以有效清除受者体内的DSA,可以安全、有效地预防高致敏人群肾移植术后急性排斥反应。     

肾移植受者群体反应性抗体监测的临床意义

目的 分析群体反应性抗体（PRA）监测对预测肾移植受者排斥反应发生的意义及探讨对高水平PRA受者的临床处理.方法 应用酶联免疫吸附分析法（ELISA法）动态监测肾移植受者的PRA水平,以PRA≥10%为阳性,10%≤PRA＜50%为低致敏、PRA≥50%为高致敏,并对37例术前高致敏患者行血浆置换.结果 1527例肾移植受者中,PRA阳性350例（22.9% ）,其中高致敏 94例（26.8% ）;PRA阳性组排斥反应发生率（21.1% ）高于PRA阴性组（3.8% , P〈0.01）, 术后PRA转为阳性组排斥反应发生率高于PRA无变化组（P〈0.01）,行血浆置换受者与未行血浆置换受者排斥反应发生率无差异（P〉0.05）,接受过移植、多次妊娠、多次输血受者易致敏,HLA-A、B、DR配型错配抗原〉3个受者急性排斥的发生率（16.9% ）明显高于错配抗原≤3个受者（1.7% , P〈0.01）.结论 动态监测PRA水平有助于预测排斥反应的发生.     

高度致敏受者的肾移植术

目的 探讨高度致敏肾移植受者的组织配型和抗排斥治疗方案。方法 回顾性分析45例高度致敏肾移植受者的HLA抗体、HLA配型和肾移植后抗排斥反应治疗效果。结果 肾移植术后发生超急性排斥反应2例(4．4％)，急性排斥反应9例(20.9％)，经激素、抗胸腺细胞球蛋白、血浆置换等治疗后均逆转。人／肾1年存活率分别为95．6%／91．1％。结论 避开相应抗体的良好HLA配型，是高度致敏受者肾移植成功的关键。术后采用抗胸腺细胞球蛋白短程诱导、并用他克莫司、霉酚酸酯治疗，能减少急性排斥的发生率，提高移植物的存活率。     

广泛致敏受者肾移植的处理策略

广泛致敏受者 (PRA >5 0 % )肾移植是器官移植领域难题之一 ,由于较难寻找与其相匹配的肾脏 ,故经常需要一个长时间等待 ,致使大部分患者丧失移植机会 ;并且行肾移植术后其超急性排斥反应和急性排斥反应的发生率高 ,严重影响肾移植成功率和移植肾的存活率。目前国内外对广泛致敏受者的处理策略为 :良好的组织配型、血浆置换和免疫吸附、静脉注射用免疫球蛋白、一些免疫诱导剂和免疫抑制剂的应用等。     

致敏肾移植受者主要组织相容性复合物I类链相关基因A抗体表达对预后的影响

目的 探讨致敏肾移植受者(群体反应性抗体PRA>20%)主要组织相容性复合物I类链相关基因A抗体（MICA-Ab）的表达对患者预后的影响。 方法 收集本院2007年8月至2010年4月行肾移植的致敏受者51例,其中29例接受蛋白A免疫吸附,并在吸附前后行MICA-Ab检查;另22例未接受免疫吸附,在入院时行MICA-Ab检查。回顾分析移植受者人类白细胞抗原（HLA）、急性排斥反应、术后1周和4周Scr水平与MICA-Ab的关系。 结果 51例受者中16例MICA-Ab表达阳性（31.4%）,MICA-Ab表达阴性与阳性受者的急性排斥发生比例差异无统计学意义。PRA>40%受者的MICA-Ab表达显著高于PRA≤40%受者（P < 0.05）。HLA错配对MICA-Ab表达无显著影响。在接受免疫吸附受者中,MICA-Ab阳性组和阴性组出院时Scr水平差异无统计学意义;未接受免疫吸附受者情况相似。MICA-Ab水平在蛋白A免疫吸附后显著下降。 结论 MICA-Ab在致敏受者中表达升高,然而对受者预后无显著影响。蛋白A免疫吸附可有效去除致敏受者体内MICA-Ab。     

HLA配型及受者PRA情况对致敏患者肾移植后2年疗效的影响

目的 探讨HLA配型及受者PRA情况对致敏患者肾移植后2年疗效的影响.方法 测定73例预致敏肾移植受体体内抗-HLA抗体的致敏程度及抗体特异性,并与81例未致敏受体进行比较,受体以及相应供体的HLA基因型均采用序列特异性引物PCR(PCR-SSP)进行分析,分析了影响早期移植结果 的因素(移植物的2年排斥率和生存率),包括HLA错配、群体反应性抗体种类及特异性,以及供者的靶抗原.结果 预致敏受者比未致敏受体的2年预后差(移植排斥率P=0.019,生存率P=0.01),无论是以6抗原匹配(AgM)或氨基酸残基匹配(Res M)为标准,对预致敏受体而言,HLA错配数对移植物排斥率,或者移植物存活率均无显著影响.与对照组相比,同时产生PRA-I、PRA-Ⅱ两种抗体的移植物受体的两年预后更差(移植排斥率P=0.001,生存率P=0.002).PRA峰值≥50%的组及其分组,移植时PRA值大于50%,他们的两年预后明显比对照组差(移植排斥率P1=0.025,P2=0.001,生存率P=0.043,P=0.024).移植时靶抗原阳性组及其分组,HLA-I阳性的组,其移植物排斥率明显高于对照组(P=0.001,P=0.001),高于靶抗原阴性组(P=0.003,P=0.001),高于靶抗原峰值阳性但移植时靶抗原阴性的受体(P=0.024,P=0.002).靶抗原阳性组还有HLA-I靶抗原阳性组的两年生存率明显低于对照组(P=0.012,P=0.001),靶抗原未明组的两年移植结果 与靶抗原阳性组类似.经过血浆滤过及免疫吸附的预致敏受者(PRA处理组)的两年移植结果 优于对照组,但无统计学意义.但未经处理的PRA预致敏受者的结果 与对照组是不同的(排斥率P=0.004,生存率P=0.005),3例HLA-I靶抗原阳性、按照氨基酸残基标准无错配的受体发生超急性排斥,1例PRA-Ⅱ阳性(靶抗原未知)的受者发生超急性排斥反应,PRA-Ⅱ靶抗原阳性的8例受者未见超急性期排斥反应.结论 移植前PRA预处理可以改善预致敏受体肾移植后的预后,避免抗原阳性供者仍然是预防超急性排斥反应和早期排斥反应的基本措施.     

PRA检测筛选肾移植致敏受者的研究进展

ＰＲＡ检测作为组织相容性配型项目之一，对了解受者体内各种抗ＨＬＡ抗体的水平及致敏状况，预测移植术后发生超急性排斥和加速性排斥反应的机率提供了客观依据，特别是对曾发生过超排及再次肾移植者的筛选更具有重要意义。     

肾移植后急性排斥反应发生相关术前因素分析

目的探讨影响肾移植术后发生急性排斥反应的相关术前因素,为预防移植肾急性排斥反应的发生提供临床依据。方法回顾性分析2002年1月～2008年12月在浙江大学医学院附属第一医院肾脏病中心首次接受同种异体尸体肾移植受者1316例资料,记录基线资料及术后急性排斥反应发生情况;按群体反应性抗体(PRA)水平10%和≥10%将受者分为PRA阴性组和致敏组;以2005年10月1日为界分为回顾性HLA配型组和前瞻性HLA配型组。统计分析各基线资料对术后急性排斥反应发生的影响以及不同组间急性排斥反应发生率的差异。结果手术时受者年龄、术前PRA水平、热缺血时间、HLA错配数对术后急性排斥反应的发生有显著影响。致敏组术后6个月内急性排斥反应发生率(58.8%比17.9%,P0.001)以及6个月内组织病理学检查证实急性排斥反应发生率(29.4%比11.9%,P=0.028)均显著高于PRA阴性组。采用前瞻性HLA配型后受者HLA错配数减少,且术后6个月内急性排斥反应发生率也降低(20.9%比15.5%,P=0.012)。结论术前检测受者的PRA水平从而准确评估其致敏状态,尽可能选择良好的HLA配型谱可减少移植肾术后急性排斥反应的发生。     

HLA致敏原性错配对肾移植受者急性排斥反应发生率的影响

目的：探讨供受者HLA致敏原性错配(IM)对肾移植受者急性排斥反应发生率的影响。方法：回顾性分析196例首次肾移植受者IM对肾移植术后肾功能的恢复时间及1年内排斥反应发生率情况。结果：IM对肾移植术后肾功能恢复时间无明显影响；IM患者1年内急性排斥率明显增加；各类位点IM对肾移植术后急性排斥反应的影响进行比较，A位点影响不大，B位点与急性排斥反应有关，DR位点IM可致急性排斥反应明显增加。结论：在临床采用氨基酸残基配型标准判断组织配型的同时，IM不容忽视，HLA-B位点IM与肾移植术后急性排斥反应相关，HLA-DR位点IM明显影响肾移植术后排斥反应发生率。     

静脉注射用免疫球蛋白对降低高致敏肾移植受者群体反应性抗体的作用

目的 观察并分析静脉注射用免疫球蛋白(IVIG)在高致敏受者肾移植中的应用效果.方法 回顾性分析18例群体反应性抗体(PRA)阳性的高致敏肾移植受者的临床资料,所有受者均应用IVIG进行治疗.观察治疗后受者的抗体水平、术后排斥反应发生率,并结合文献资料对IVIG的应用进行综合评价.结果 应用IVIG前,18例受者中有2例PRA水平为100%,4例＞70%、8例＞50%、4例＞30%,应用IVIG后所有受者PRA水平明显下降,其中2例受者转为全阴性,15例受者抗HLA-Ⅰ类和抗HLA-Ⅱ类抗体＜30%,两者比较,差异有统计学意义(P＜0.01),应用IVIG后肾移植效果良好,受者术后急性排斥反应发生率为38.5%,未出现移植肾的丢失.结论 应用IVIG能有效降低高致敏肾移植受者的PRA水平,联合应用生物抗体和免疫抑制剂可以使更多高致敏受者获得肾移植机会,并且术后应用IVIG具有抗排斥反应作用.     

Transplant Accommodation in Highly Sensitized Patients: A Potential Role for Bcl-xL and Alloantibody

Transplantation of renal allografts into recipients with circulating anti-HLA antibodies results in hyperacute rejection. In some cases, however, antibodies return without causing harm; this phenomenon has been termed 'accommodation'. We have investigated this process in human allotransplantation. We removed anti-HLA antibodies by immunoadsorption in seven highly sensitized dialysis patients who subsequently underwent renal transplantation. Immunohistochemistry of renal biopsies for IgG and antiapoptotic proteins was performed. We also developed a model of 'accommodation' using anti-HLA antibodies eluted from sensitized patients and incubated with human umbilical vein endothelial cells (HUVECs) at different concentrations. Their effect on HUVEC phenotype was then analysed. Anti-donor antibody returned in 4/7 patients, without evidence of hyperacute rejection. Three out of four of these 'accommodated' grafts showed specific endothelial up-regulation of Bcl-xL and 2/2 tested positive for endothelial IgG deposition. HUVECs incubated with subsaturating concentrations of anti-HLA antibody showed increased expression of Bcl-xL, were rendered refractory to endothelial cell activation and became resistant to complement-mediated lysis. In contrast, HUVECs incubated with saturating concentrations underwent activation and expressed low levels of Bcl-xL. In conclusion, endothelial Bcl-xL expression defines the accommodation process in human allografts and this phenotype may be initiated by exposure of endothelium to low concentrations of anti-donor HLA antibodies.     

高度致敏肾移植患者的围术期处理

目的 探讨高度致敏肾移植患者的围手术期处理.方法 对22例高度致敏肾移植患者术前组织配型及预处理,术后抗排异方案以及肾功恢复情况进行研究.结果 17例患者术前经血浆置换3～8次后群体反应性抗体(PRA)降至30%以下,5例患者术前PRA仍大于50%.术后发生超急性排斥反应(HAR)1例(9.9%),抗排异反应未能逆转,予以切除移植肾;急性排斥反应(AR)8例(36.3%),经甲强龙+ATG(ALG)冲击治疗后6例肾功恢复正常,2例转为肾功能延迟恢复(DGF);术后DGF5例(22.7%),予以血液透析+低剂量抗排异药物维持,肾功均恢复正常.结论 避开相应抗体进行良好的组织配型,是高度致敏患者肾移植成功的关键;术前行血浆置换降低高度致敏患者PRA,使用ATG或ALG可降低手术风险,提高排斥反应逆转率.     

Impaired renal allograft function: a comparative study with angiography and histopathology.

We reviewed 47 renal transplant recipients who had undergone angiography and transplant biopsy to evaluate impaired allograft function. Angiographic criteria for rejection were seen in all allografts with hyperacute rejection, accelerated rejection and chronic rejection, and in 13 of 17 allografts with acute cellular rejection. Angiography was normal in allografts with vasomotor nephropathy or transplant glomerulopathy. Angiography is an accurate method for the diagnosis of most causes of post-transplant dysfunction.     

Immunoadsorption of sensitized kidney transplant candidates immediately prior to surgery

Patients with anti-human leucocyte antigen (HLA) antibodies from previous transplantation, blood transfusion are highly sensitized and at risk to hyperacute renal graft loss. As these antibodies are identified to be of pathogenic importance, an effective removal may allow successful transplantation. Six 'high risk patients' [panel-reactive antibodies (PRA) >30% or retransplanted patients with an acutely rejected first graft within 6 months from surgery] were treated by protein A immunoadsorption (IA) immediately prior to transplantation. We treated the calculated plasma volume one to three times prior to surgery: mean 4600 mL (range 2100-10 200 mL). After transplantation we repeated the sessions according to antibody (Ab) recurrence, graft function and signs of rejection. The panel reactive Ab were reduced from mean 65% pre-IA (range 35-85) to lowest 15% (range 0-55). After the course they reappeared to 30% (range 0-90). Five of the six patients had no clinical signs of vascular rejection. At a follow-up of mean 54 months (+/-14) four grafts still function with a mean serum creatinine of 172 micromol/L (+/-57). Protein A IA is a safe and effective adjunct in the treatment of highly sensitized patients awaiting renal transplantation. The treatment immediately prior to operation can prevent hyperacute rejection and increases the graft survival in these patients.     

Specific absorption of lymphocytotoxic alloantibodies by the liver in inbred rats

It has been suggested that liver allografts are less sensitive to lymphocytotoxic antibodies than other organ allografts. In this experimental study in sensitized inbred rat recipients, we have used extracorporeal liver hemoperfusion to study interactions between the liver and lymphocytotoxic antibodies. Donor-specific liver hemoperfusion can delay hyperacute rejection of heart allografts and reduce the level of lymphocytotoxic antibodies. Immunofluorescence examination of the hemoperfused liver revealed deposits of C3 on Kupffer cells and of IgG on sinusoidal cells. In control rats in which a third-party liver, a donor-specific splenic or renal hemoperfusion was performed, heart allograft survival was less prolonged. The decrease in antibody levels was not significant and the deposit of C3 and IgG was much less evident. Similarly, previous blockade of the Kupffer cells of the donor-specific hemoperfused liver by dextran sulfate suppressed the effect of liver hemoperfusion. These results support the hypothesis that resistance of the liver to hyperacute rejection might be due to a massive and nontoxic absorption of lymphocytotoxic antibodies onto nonparenchymal liver cells.     

双滤过法血浆分离治疗移植肾术后排斥反应及术前高度致敏

目的探讨肾移植术后排斥反应和术前高度致敏的治疗方法。方法采用双滤过法血浆分离术（ＤＦＰＰ）治疗３６例术后排斥反应和９例术前高度致敏患者。结果２４例急性排斥中２２例逆转,１０例加速性排斥（ＡＣＲ）全部逆转,１例慢性排斥肾功能稳定,１例超急性排斥（ＨＡＲ）摘除移植肾;排斥反应采用ＤＦＰＰ治疗者其一年移植肾生存率为８４．０％。去致敏抗体者８例已接受肾移植,其中１例术后发生ＨＡＲ。结论认为ＤＦＰＰ是治疗排斥反应和预防高敏患者术后发生致敏抗体介导的ＨＡＲ和ＡＣＲ的有效方法,显著提高了排斥反应的逆转率和移植肾生存率     

Increased risk of antibody-mediated rejection of reduced-size liver allografts

Because of the shortage of liver allografts in children, transplantation of reduced-size liver allografts from adult cadaveric donors or living, related donors is being done more frequently. Reduced-size liver allografts may be used in cases of ABO incompatibility and T-cell warm cross-match positivity. This experimental study in inbred rats was undertaken to determine if reduced-size liver allografts are more sensitive to antibody-mediated rejection than full-size liver allografts. Brown-Norway (BN) (RT1(n)) rats were sensitized by three successive skin grafts at 10-day intervals. Then orthotopic Lewis (LEW) (RT1(1)) liver grafts were transplanted into these BN rats. Full-size liver allografts were compared with reduced-size liver allografts (70% of donor liver). Control groups were composed of full-size and/or reduced-size isografts. Titers of specific antibodies were assayed using a complement-dependent assay before and after orthotopic liver transplantation. Histological and immunofluorescence studies (IgG, IgM, C(3), and fibrinogen deposits) were assessed. Recipients of reduced-size liver allografts died of hyperacute rejection at 36.6 +/- 4.1 h, significantly earlier than recipients receiving full-size liver allografts, which died of accelerated acute rejection at 259.2 +/- 25.2 h (P < 0.001). Either full-size or reduced-size isograft recipients survived indefinitely. A decrease in the titers of donor-specific antibodies was observed in both groups of animals. Slight deposits of IgG, IgM, C(3), and fibrinogen were observed in recipients of reduced-size liver allografts, whereas larger deposits were observed in recipients of full-size liver allografts. Our data demonstrate that there is an increased risk of antibody-mediated rejection of reduced-size liver allografts in sensitized recipients. This may have important clinical implications for partial liver grafting in cases of ABO incompatibility and T-cell warm cross-match positivity.     

预防预致敏受者尸体肾移植术后急性排斥反应的临床研究

目的 探讨HLA配型及新型免疫抑制剂治疗方案对预防致敏患者肾移植术后急性排斥反应的影响.方法 实验组选择46例术前致敏患者(术前PRA>10%),对照组选择同期705例未致敏患者(术前PRA<10%),实验组患者均采用诱导治疗(ATG 100 mg/d,5～7 d)+三联免疫抑制剂维持治疗方案(FK506+MMF+激素),比较两组间患者术后急性排斥反应发病率、移植肾功能延迟恢复比例、移植肾/患者一年存活率,同时分析HLA配型对移植肾急性排斥反应的影响.结果 实验组与对照组急性排斥反应的发病率分别为30.43%和19.57%(P<0.05);移植肾功能延迟恢复发病率分别为60.86%和11.87%(P<0.01).患者一年存活率分别为95.65%和98.44%,一年移植肾存活率分别为93.48%和96.88%;一年时平均血肌肝分别为130 mmol/dL和125 mmol/dL,差异无统计学意义.实验组患者HLA相配率(4.2)明显高于对照组患者(2.8)(P<0.05).实验组中HLA配型2-4错配的患者与0-2错配患者的急性排斥反应发病率有显著性差异,高度致敏患者(移植术前PRA>50%)急性排斥反应发病率较低度致敏患者(PRA 10%～20%)发病率高,移植术后PRA水平持续升高者更容易出现急性排斥反应.结论供、受者之间良好的HLA配型及采用新型免疫抑制药物治疗方案,对预防及减轻致敏患者移植术后急性排斥反应疗效确切.     

Flow cytometry crossmatching as a predictor of acute rejection in sensitized recipients of cadaveric renal transplants

Flow cytometry crossmatching (FCXM) was developed as a more sensitive assay than the standard complement-dependent cytotoxicity crossmatch (CDCXM) for the detection of anti-donor antibodies, that mediate hyperacute rejection and graft loss in the early post-transplant period in renal transplant recipients. The role of FCXM in predicting long-term clinical outcome in renal allograft recipients is unclear. This study examines the role of FCXM in predicting long-term clinical outcome in highly sensitized recipients of cadaveric renal transplants. All patients (n = 100) with peak panel reactive antibody (PRA) levels > 30%, who received cadaveric renal transplants between 1/1/'90 and 12/31/'95 at our institution, were divided into FCXM + and FCXM - groups. The incidence of acute rejection was determined for each group during the first yr after transplant. Graft survival rates at 1, 2, and 3 yr, and creatinine levels were also compared between groups. FCXM + patients experienced a higher incidence of acute rejection during the first yr after transplant (69 vs. 45%), and a higher percentage of FCXM + patients had more than one episode of acute rejection during the first yr after transplant (34 vs. 8%) when compared to FCXM - patients. There was no statistically significant difference in 1-, 2-, or 3-yr graft survival between FCXM + and FCXM - patients (76 vs. 83, 62 vs. 80, 62 vs. 72%, respectively). These results suggest that sensitized FCXM + cadaveric renal transplant recipients have a higher incidence of acute rejection episodes in the first yr after transplant. Given the association of multiple rejection episodes with poor long-term allograft survival, FCXM may be a useful predictor of long-term clinical outcome in this sub-group of renal transplant recipients.