C4d沉积在抗体介导的慢性排斥反应中的临床意义

目的 探讨移植肾肾小管周围毛细血管补体片段C4d沉积与抗体介导的慢性排斥反应的病理形态、移植肾功能及预后的关系.方法 应用免疫组织化学技术检测77例肾移植受者移植肾肾小管周围毛细血管中C4d的沉积情况,根据检测结果分为C4d阳性组(35例)和C4d阴性组(42例).检测并比较C4d阳性和阴性组受者移植肾的病理形态结构、移植肾功能及预后.结果 与C4d阴性组比较,C4d阳性组受者移植肾肾小管萎缩和肾小球基底膜增生分层的例数明显增多,差异有统计学意义(P＜0.05).C4d阳性组受者的血肌酐水平在移植肾穿刺后12个月时较C4d阴性组受者明显升高,分别为(379.1±260.2)μmol/L和(260.5±175.3)μmol/L,差异有统计学意义(P＜0.05).C4d阳性组受者移植肾穿刺明确C4d阳性后1年内移植肾存活率为62.9%(22/35),而阴性组受者为83.3%(35/42),两组比较,差异有统计学意义(P＜0.05).结论 在抗体介导的慢性排斥反应中,移植肾C4d沉积常见的病理学改变为肾小管萎缩和肾小球基底膜增生分层,C4d阳性抗体介导的体液性慢性排斥反应加快了移植肾功能丧失的进展速度,使C4d阳性受者的移植肾功能丧失率升高,导致存活率降低.     

移植肾组织中补体C4d沉积在CAN的诊断和治疗中的临床意义

目的 探讨移植肾组织中补体C4d沉积在慢性移植肾肾病(CAN)的诊断和治疗中的临床意义.方法 将2000年1月至2008年8月间诊断为CAN,且已行移植肾活检,并能收集到活检后2年以上随访资料者纳入研究.符合标准者共有86例,其中男性53例,女性33例,移植时年龄18～65岁.应用免疫组织化学染色方法检测移植肾组织活检标本C4d的表达.所有患者在行移植肾穿刺诊断为CAN后均给予了常规治疗.结果 86例患者中,C4d沉积阳性者(C4d阳性组)39例,C4d沉积阴性者(C4d阴性组)47例,两组患者在性别、年龄、供肾来源、多次移植、移植时群体反应性抗体水平等各指标的比较,差异均无统计学意义(P＞0.05).活检2年后,C4d阳性组和阴性组患者的SCr水平分别为(551.5±140.4)和(443.0±133.1)μmol/L,两组比较,差异有统计学意义(P＜0.05);并且C4d阳性组患者移植肾功能丧失率(23.1%,10/39)也显著高于C4d阴性组(8.5%,4/47),两组比较,差异有统计学意义(P＜0.05).CAN治疗前,C4d阳性组发生高血压和高血脂者多于阴性组(P＜0.05);常规治疗后,剔除移植肾功能丧失者,两组间发生高血压、高血脂、高血糖和高血尿酸者差异无统计学意义(P＞0.05).结论 C4d阳性的CAN患者提示有慢性体液排斥反应的参与,临床常规治疗预后较差,若针对体液免疫反应进行干预,能够改善移植肾长期存活.     

肾移植术后血清抗MICA抗体与慢性排斥反应的相关性

目的 探讨肾移植受者的抗MICA抗体水平与慢性排斥反应的相关性及其对移植肾功能的影响.方法 共有105例受者被作为研究对象纳入分析,其中发生慢性排斥反应者(慢排组)43例,移植肾功能正常者(对照组)62例.记录两组受者术前群体反应性抗体(PRA)、HLA抗原错配数、供肾冷缺血时间、出院时血清肌酐(SCr)水平、术后免疫抑制方案以及入组时间(入组时距肾移植手术时间)等资料,并进行比较.受者分组后,抽取受者外周血,检测SCr及抗MICA抗体水平,抗MICA抗体的检测采用Luminex 100免疫磁珠流式细胞仪技术.观察与比较抗MICA抗体阳性受者和抗MICA抗体阴性受者间术后3个月内发生急性排斥反应(AR)的次数和移植肾功能的差异.移植肾功能的评价采用血清肌酐变化率(△SCr/M),即(入组时SCr值-出院时SCr值)/入组时间.结果 两组受者在性别、年龄、HLA抗原错配数、供肾冷缺血时间、术后免疫抑制方案、出院时SCr水平及入组时间的比较,差异均无统计学意义(P＞0.05).分组后,慢排组受者SCr水平和抗MICA抗体阳性受者比例均明显高于对照组,两组比较,差别均有统计学意义(P＜0.01,表1).抗MICA抗体阳性受者术后3个月内发生的AR次数明显多于抗MICA抗体阴性受者,二者比较,差异有统计学意义(P＜0.05).抗MICA抗体阳性受者的△SCr/M为8.3±3.6,明显高于抗MICA抗体阴性受者的2.4±2.6,二者比较,差异有统计学意义(P＜0.05).结论 抗MICA抗体的表达与慢性排斥反应的发生相关,移植前进行MICA配型可减少术后移植肾慢性排斥反应的发生,有助于延长移植肾的长期存活.     

急性细胞性排斥伴补体裂解片断C4d沉积对移植肾预后的影响

目的探讨急性细胞性排斥伴肾小管周围毛细血管补体裂解片断(C4d)沉积对移植肾预后的影响。方法经病理证实的急性细胞性排斥肾移植患者145例,根据病理表现有否肾小管周围毛细血管C4d沉积,将其分为细胞性排斥+C4d阳性组(C4d阳性组)64例,单纯细胞性排斥组(C4d阴性组)81例。比较两组术前一般情况、排斥反应发病情况、抗排斥治疗、移植肾失功率及移植肾存活率。结果两组的术前一般情况比较差异无统计学意义(P0.05)。C4d阳性组的急性细胞性排斥反应发生时间明显早于C4d阴性组,比较差异有统计学意义(P0.05)。两组Banff分型Ⅰ型与Ⅱ型比例差异有统计学意义(P0.01)。随访期间C4d阳性组有22例(34%)移植肾失功,明显高于C4d阴性组的11例(14%),比较差异有统计学意义(P0.01)。Kaplan-Meier法分析发现C4d阳性组的移植肾存活率明显低于C4d阴性组(P0.01),移植肾的5年生存率分别为51%、79%。结论急性细胞性排斥反应伴肾小管周围毛细血管C4d沉积的肾移植患者,术后较早发生排斥反应,抗排斥治疗效果较差,移植肾存活率低。     

移植肾切除标本中C4d表达分析

目的 检测C4d在难治性排斥反应移植肾组织中的表达情况,分析体液免疫参与难治性排斥反应与移植肾长期存活的相关性.方法 以40例难治性排斥反应致移植肾切除患者为研究组(A组),20例移植术后因移植肾功能一过性异常行穿刺活检患者作为对照组(B组);应用C4d多克隆抗体对移植肾组织的石蜡切片行免疫组织化学染色,检测C4d在切除移植肾中的表达情况,分析2组标本中C4d的表达差异.结果 A组中检测到C4d阳性17例(42.5%),17例C4d阳性患者中存活时间＜5年的移植肾12例(70.6%),明显多于存活时间＞5年者的阳性数(5例,29.4%);B组中C4d阳性2例(10.0%),2组比较P=0.024.A组中受者男28例,女12例;年龄27～67岁,平均(39±10)岁;冷缺血时间6～12 min,热缺血时间170～720 min;免疫抑制方案为吗替麦考酚酯加环孢素加糖皮质激素19例、吗替麦考酚酯加他克莫司加糖皮质激素7例、硫唑嘌呤加环孢素加糖皮质激素14例;二次移植4例;31例术后仍有高血压.经t检验与X2检验,以上各因素与移植.肾C4d的阳性沉积无明显相关(P＞0.05).结论 体液免疫参与的难治性排斥反应是影响移植物长期存活的危险因素.     

补体裂解片断C4d在移植肾急性排斥反应中的临床意义

目的探讨肾小管周围毛细血管补体裂解片断(C4d)沉积在移植肾急性排斥反应中的临床意义。方法对肾移植后发生急性排斥反应的78例受者进行移植肾活体穿刺检查,共获取移植肾活检穿刺标本86份。根据Banff97病理分型将86份活检标本分为BanffⅠ型32份,Ⅱ型51份,Ⅲ型3份。应用免疫组织化学法检测出86份标本中有30份出现肾小管周围毛细血管C4d沉积,阳性率为34.9%。分析C4d阳性其与Banff97分型、术前一般情况、抗排斥治疗、移植肾功能及移植肾预后的关系。结果BanffⅠ和Ⅱ型受者移植肾中C4d阳性率分别为21.9%和39.2%,两者相比差异无统计学意义(P=0.101)。有妊娠史、术前群体反应性抗体(PRA)>30%和再次移植的受者C4d阳性率较高。C4d阳性的受者发生排斥反应时血肌酐较阴性受者高,分别为(312.56±196.26)μmol/L和(210.97±136.59)μmol/L,两组差异有统计学意义(P=0.0115)。C4d阳性受者对激素和ATG冲击治疗与阴性受者比较,敏感率明显降低。C4d阳性的受者移植肾1年生存率较阴性受者低,分别为64.3%和90.0%,两组间差异有统计学意义(P=0.006)。结论移植肾C4d阳性的受者发生排斥反应时,对常规的激素冲击和ATG抗排斥治疗不敏感,血肌酐明显升高,移植肾1年存活率下降,受者预后较差。     

老年活体供肾移植术后供者安全性及受者移植效果的分析

目的 分析老年活体供肾移植术后供者的安全性及受者的移植效果.方法 回顾性分析251例亲属活体供肾移植的临床资料.根据供者年龄,将251例活体供肾移植分为老年供肾组(≥55岁)和中青年供肾组(<55岁),对手术前后两组供、受者的血清肌酐(Cr)、肾小球滤过率(GFR)、内生肌酐清除率(Ccr)、并发症、平均住院时间以及受者的人/肾存活率、急性排斥反应发生率进行比较和分析.结果 老年供肾组和中青年供肾组供者手术前后血Cr水平的差异无统计学意义(P>0.05),而Ccr的差异有统计学意义(P<0.05).老年供肾组与中青年供肾组供者比较,术前总GFR、留存肾GFR及术后10 d留存肾GFR比较,差异均无统计学意义(P>0.05);老年供肾组供者术后10 d与术前的留存肾GFR比较,差异无统计学意义(P>0.05);中青年供肾组供者术后10 d的留存肾GFR较术前明显上升,差异有统计学意义(P<0.05).老年供肾组与中青年供肾组受者比较,手术前后各相应时间点的血Cr水平差异无统计学意义(P>0.05).老年供肾组和中青年供肾组供者平均住院时间分别为(16.67±7.78)d和(16.11±5.89)d(P>0.05),受者平均住院时间分别为(29.61±24.28)d和(28.76±19.27)d(P>0.05).两组受者6个月内急性排斥反应发生率分别为6.50%和5.75%(P>0.05).老年供肾组受者术后死亡1例,中青年供肾组死亡3例,并有1例因急性排斥反应切除移植肾.结论 老年活体供肾移植术前应对供者进行严格的选择,在进行全面系统评估的前提下,可以保证供者术后的安全以及受者的移植效果.     

再次肾移植受者和移植肾长期预后影响因素分析

目的探究再次肾移植受者和移植肾存活情况及长期预后影响因素。 方法回顾性分析1991年1月1日至2017年12月31日于浙江大学医学院附属第一医院肾脏病中心接受肾移植受者临床资料。共纳入再次肾移植受者37例,首次肾移植受者5 374例。根据再次肾移植受者移植肾存活时间长短,将其分为长期存活组(19例,>5年)和短期存活组(18例,≤5年)。采用成组t检验比较长期和短期存活组供受者年龄、首次与再次肾移植间隔时间、HLA错配数和再次移植供肾冷/热缺血时间。采用卡方检验比较长期和短期存活组受者性别、再次移植供肾类型、再次移植前后群体反应性抗体阳性比例、首次移植失功移植肾切除比例、再次移植前免疫诱导比例及再次移植后移植肾功能延迟恢复(DGF)和急性排斥反应发生比例。采用Kaplan-Meier法分析再次和首次肾移植受者/移植肾1、5和10年存活率。采用Cox比例风险模型分析影响再次肾移植术后移植肾长期存活影响因素。P<0.05为差异有统计学意义。 结果截至2018年3月1日,37例再次肾移植受者中位随访时间为152个月(11～323个月),2例死亡,18例发生移植肾失功,17例移植肾功能稳定。5 374例首次肾移植受者中位随访时间为108.9个月(0.1～350.0个月),459例死亡,1 343例发生移植肾失功。再次移植组受者/移植肾1、5和10年存活率分别为86%/81%、86%/62%和82%/36%,首次移植组受者/移植肾1、5和10年存活率分别为99%/98%、93%/89%和88%/80%。再次移植组移植肾1、5和10年存活率均低于首次移植组(χ²＝60.816、25.110和43.900,P均<0.05);再次移植组受者1年存活率低于首次移植组,差异有统计学意义(χ²＝40.409,P<0.05)。长期和短期存活组受者再次移植后移植肾DGF和急性排斥反应发生比例差异均有统计学意义(χ²＝4.039和4.748,P均<0.05)。Cox回归分析结果示DGF和急性排斥反应是影响再次肾移植受者移植肾长期存活的独立危险因素,差异有统计学意义(RR＝4.317和4.571,P均<0.05)。 结论再次肾移植受者移植肾存活率低于首次肾移植受者,DGF和急性排斥反应是影响再次移植受者移植肾存活的独立危险因素。     

肾移植术后抗体监测和移植肾病理学检查有助于早期诊断抗体介导的排斥反应

目的分析肾移植术后抗人类白细胞抗原(HLA)抗体监测和移植肾穿刺病理学检查早期诊断抗体介导的排斥反应(AMR)的必要性。方法筛选51例术后产生新生供体特异性抗体(dn DSA)的受者,检测供体特异性抗体(DSA)及其结合C1q的能力,同时进行移植肾穿刺病理诊断。对于符合AMR诊断的受者,比较分析移植肾功能不稳定组和稳定组受者的DSA类别、补体结合能力和移植肾病理组织Banff评分。对无排斥反应组、移植肾功能不稳定组和稳定组受者的移植物进行Kalan-Meier生存分析。结果在移植肾功能不稳定组和稳定组受者中,HLA抗体的不同类别、DSA的平均荧光强度(MFI)值、补体相关检测C1q结合力和C4d管周毛细血管沉积情况差异均无统计学意义(均为P0.05)。在组织形态学损伤方面,两组在微血管炎、动脉内膜炎、肾小管-间质炎、移植肾小球病、肾小管萎缩-间质纤维化等表现的Banff评分差异均无统计学意义(均为P0.05)。移植肾功能不稳定组受者移植物累积存活率显著低于稳定组,稳定组明显低于不符合排斥病理诊断的受者(P=0.002)。结论肾移植术后定期监测抗HLA抗体和做移植肾病理穿刺检查非常必要,有助于早期发现和诊断AMR。     

CD20阳性淋巴细胞在慢性移植肾肾病组织中浸润的意义

目的 探讨肾移植术后慢性移植物肾病(CAN)组织CD20阳性淋巴细胞浸润的临床意义及其机制.方法 选择肾移植术后2年内活检证实为CAN病例为研究对象,应用免疫组织化学方法检测补体C4d的沉积和CD20阳性淋巴细胞在移植肾组织的浸润,同时分析临床随访资料.结果 人选CAN病例44例,其中CD20阳性淋巴细胞浸润13例(29.5％),CD20阴性为31例(70.5％),移植肾组织不同病理分级者中CD20阳性者所占比例的差异无统计学意义(P＞0.05).44例中,12例(27.3％)出现管周毛细血管内皮细胞(PTC)补体C4d的线性沉积,CD20阳性和阴性者中补体C4d表达阳性率的差异无统计学意义(P＞0.05).确诊为CAN时移植肾组织CD20为阴性和阳性者的肾功能分别为( 140.8±22.0)μmol/L和(183.5±25.5) μmol/L(P＜0.01),1年后分别为(165.6±37.6)μmol/L和(242.2±59.1 )μmol/L(P＜0.01).结论 CD20阳性淋巴细胞在移植肾组织的浸润与移植物的预后相关,其机制可能不是通过慢性体液免疫反应.     

C4d deposition in allograft renal biopsies is an independent risk factor for graft failure

Aim:   Association between C4d deposition and renal allograft survival is still uncertain. We retrospectively evaluated the clinical outcome of C4d deposition in allograft renal biopsies.
Methods:   One hundred and fifty biopsies from 150 patients with a histological diagnosis of acute rejection from December 1997 to March 2007 were included. Paraffin-embedded sections were stained with a polyclonal antibody using an immunoperoxidase technique. Detailed clinical data were obtained by retrospective review.
Results:   C4d was stained positively in 74 (49.3%) of 150 cases: 47 (61.5%) biopsies showed diffuse C4d deposition and 27 (38.5%) showed focal C4d deposition. During follow up, significantly more C4d-positive patients (24/74 patients, 32.4%) lost their grafts, compared with the C4d-negative group (10/76 patients, 13.2%) ( P  = 0.005). After a Kaplan–Meier analysis, grafts from the C4d-negative group had a markedly higher survival as compared with the C4d-positive group ( P  = 0.003, log–rank test). Graft survival among C4d-negative, C4d diffuse-positive, and C4d focal-positive groups was significantly different ( P  = 0.007, log–rank test). The graft survival rate among C4d-negative patients in early (<6 months) and later biopsies (>6 months), and C4d-positive patients in early and in later biopsies was different ( P  = 0.028, log–rank test). The adjusted risk ratio of graft failure after Cox proportional hazards multivariate analyses for C4d-positive patients was 3.309 (95% confidence interval, 1.413–6.537; P  = 0.004).
Conclusion:   Patients with C4d deposition had an inferior graft survival, especially with diffused C4d deposition, and later experienced acute rejection. C4d deposition was an independent risk factor for graft survival.     

C3D deposition in peritubular capillaries indicates a variant of acute renal allograft rejection characterized by a worse clinical outcome

BACKGROUND: C4d deposition in peritubular capillaries (PTCs) is a sign of humoral renal allograft rejection and an independent predictor of graft survival. Few investigators have focused on the meaning of capillary C3 deposition in rejecting grafts. Because C3 production can result from both classic and alternative pathway activation of the complement cascade, it is not clear whether C3 deposition indicates a distinct entity of acute rejection (AR) or merely represents a separate form of C4d-positive AR. METHODS: We examined the deposition of C3d in the PTCs of recipients with AR in the first year posttransplantation (n=30). Clinical outcome variables and histology were compared with C3d-negative control patients (n=82). RESULTS: C3d-positive patients demonstrated more frequent preexisting T-cell antibodies (57%) and more re-transplants (37%), and they received more blood transfusions (mean 10.3 units). C3d-positive patients experienced more frequent multiple AR episodes (57%) and delayed graft function (36.7%). All nine C3d-positive recipients screened for posttransplantation donor-specific human leukocyte antigen antibodies demonstrated positive results. Graft failure occurred in 23% of C3d-positive recipients (7.3% in the control group) (P=0.03). C3d-positive biopsies showed significantly less tubulitis (P=0.03), whereas congestive PTCs with intraluminal accumulation of polymorphonuclear leukocytes were conspicuous. Thrombi, fibrinoid necrosis, and acute tubular necrosis were not more pronounced. In 19% of rejection biopsies, C3d deposition in PTCs was present without C4d deposition. In the remaining biopsies, C3d and C4d deposition was found simultaneously. CONCLUSIONS: The deposition of complement factor C3d in PTCs indicates a variant type of AR characterized by a worse clinical outcome.     

Peritubular capillary C4d staining in late acute renal allograft rejection – is it relevant?

Abstract: Background: In the early post-transplant period, renal allograft rejection with diffuse peritubular capillary (PTC) C4d deposition predicts poor graft survival. In the late post-transplant setting, that is, one or more yr after transplantation, the implication of diffuse PTC C4d deposition is still a topic of debate. The purpose of our study was to see if diffuse PTC C4d deposition, in late acute rejection (LAR), occurring more than one yr post-transplant, has any impact on graft survival and function. Methods: We selected cases, both cadaveric as well as living donor renal transplant recipients, in whom acute rejection with PTC C4d deposition was first detected after the first year post-transplant. Recipients with multiple acute rejection episodes during the first year post-transplant were excluded from the study. The first biopsy diagnosed with LAR was considered the index biopsy (n = 40). We formed two groups: group 1, C4d-positive LAR (n = 20), and group 2, C4d-negative LAR (n = 20). Groups were matched for maintenance and post-rejection immunosuppressive therapy, baseline serum creatinine levels before the time of the index biopsy, time from transplant to index biopsy, as well as chronic allograft damage index (CADI) score in the index biopsies. We compared the rate of graft loss, and the graft function of the surviving grafts at the end of the study period, as well as histologic parameters in the index biopsy specimens between the two groups. The mean follow-up period was 20 months. Results: No significant differences in the rate of graft loss or graft function were found between groups 1 and 2 at the end of the follow-up period. Histologically, PTC margination and transplant glomerulopathy were more common in the C4d-positive group, and this difference was statistically significant. There was no statistically significant difference in the degree of plasma cell infiltrates. Conclusions: Unlike in the acute setting, the presence or absence of PTC C4d staining in renal allografts with LAR may not have a predictive value regarding graft outcome.     

Role of CXCR3 in cellular but not humoral renal allograft rejection

CXCR3, a chemokine receptor mainly expressed by T cells, is involved in animal transplant models and in human allograft rejection. CXCR3 expression was localized in formalin-fixed, paraffin-embedded renal allograft biopsies without signs of rejection (C4d-negative, Banff 0, n = 16), with C4d deposits as a sign of humoral rejection (C4d-positive, Banff 0, n = 8), with cellular rejection (C4d-negative, Banff I, n = 7) and with signs of both cellular and humoral rejection (C4d-positive, Banff 1, n = 5). Small, round infiltrating cells were CXCR3-positive. A high number of these cells was present in biopsies with cellular rejection (independent of C4d deposition). CXCR3-positive cells diffusely infiltrated the interstitium, including the tubular epithelium (tubulitis). CXCR3 scores and the area of CXCR3 staining were significantly higher in cellular rejection, when compared to biopsies without rejection, and with deposition of C4d alone. CXCR3-positive cells infiltrate renal allografts during cellular rejection, whereas C4d deposition is not associated with the recruitment of these cells.     

Acute renal allograft rejection: diagnostic significance of focal peritubular capillary C4d

BACKGROUND: Focal PTC C4d staining in acute renal allograft rejection has not been studied extensively. METHODS: Renal allograft biopsies performed after October 2003, representing the first episode of acute rejection (AR) in recipients with > or = 12 months follow-up postbiopsy, were assessed for extent of C4d and correlated with morphology, ELISA screen, donor-specific antibodies (DSA), response to treatment, and outcome. RESULTS: In 106 biopsies (16 C4d-diffuse; 24 C4d-focal; 66 C4d-negative), there were no differences among the three groups in terms of timing or grade of AR, creatinine level, tacrolimus level, and grade of interstitial fibrosis/tubular atrophy or graft loss. The C4d-diffuse group was significantly associated with less tubulitis (P=0.0021), and more chronic allograft arteriopathy (P=0.0527). Incomplete response to steroid therapy was more frequent in C4d-diffuse/focal compared with negative cases (P=0.0492). DSA frequency within 1 year of AR was highest in the C4d-diffuse (94%), followed by C4d-focal (38%), and C4d-negative (17%) groups (P<0.0001). CONCLUSION: Focal PTC C4d was associated with circulating antibodies, with a 2-fold greater diagnostic sensitivity than negative C4d staining. The finding of diffuse C4d on follow-up biopsy was significantly associated with graft loss at 1 year, regardless of index biopsy C4d results.     

Chronic humoral rejection: identification of antibody-mediated chronic renal allograft rejection by C4d deposits in peritubular capillaries

The pathogenesis of chronic renal allograft rejection (CR) remains obscure. The hypothesis that a subset of CR is mediated by antidonor antibody was tested by determining whether C4d is deposited in peritubular capillaries (PTC) and whether it correlates with circulating antidonor antibodies. All cases (from January 1, 1990, to July 31, 1999) that met histologic criteria for CR and had frozen tissue (28 biopsies, 10 nephrectomies) were included. Controls were renal allograft biopsies with chronic cyclosporine toxicity (n = 21) or nonspecific interstitial fibrosis (n = 10), and native kidneys with end-stage renal disease (n = 10) or chronic interstitial fibrosis (n = 5). Frozen sections were stained by two-color immunofluorescence for C4d, type IV collagen and Ulex europaeus agglutinin I. Antidonor HLA antibody was sought by panel-reactive antibody analysis and/or donor cross matching in sera within 7 wk of biopsy. Overall, 23 of 38 CR cases (61%) had PTC staining for C4d, compared with 1 of 46 (2%) of controls (P < 0.001). C4d in PTC was localized at the interface of endothelium and basement membrane. Most of the C4d-positive CR tested had antidonor HLA antibody (15 of 17; 88%); none of the C4d-negative CR tested (0 of 8) had antidonor antibody (P < 0.0002). The histology of C4d-positive CR was similar to C4d-negative CR, and 1-yr graft survival rates were 62% and 25%, respectively (P = 0.05). Since August 1998, five of six C4d-positive CR cases have been treated with mycophenolate mofetil +/- tacrolimus with a 100% 1-yr graft survival, versus 40% before August 1998 (P < 0.03). These data support the hypothesis that a substantial fraction of CR is mediated by antibody (immunologically active). C4d can be used to separate this group of CR from the nonspecific category of chronic allograft nephropathy and may have the potential to guide successful therapeutic intervention.     

Late developing C4d-positive humoral renal allograft rejection associated with withdrawal of mycophenolate mofetil

In renal transplantation, C4d-positive acute humoral rejection (AHR) usually develops in the early stage posttransplantation. It is clear C4d can be detected late after the operation, when it is associated with chronic renal allograft rejection. We report a case of a renal allograft recipient who experienced C4d-positive acute renal allograft rejection associated with withdrawal of mycophenolate mofetil (MMF) at 10 months after transplantation. This 21-year-old single male patient received his first cadaveric renal allograft under immunosuppression with cyclosporine, MMF, and prednisolone. The serum creatinine recovered to the normal range within 4 days. A protocol biopsy performed at 1 month after transplantation revealed no signs of rejection. The graft function was stable until 10 months postoperation, when MMF was converted to mizoribin. Three days later a biopsy showed a C4d-positive rejection. Patient had no response to the MMF combined with tacrolimus and steroid bolus therapy, which generally improves 85% of AHR among Chinese. He finally returned to dialysis. Our report suggested that C4d positive AHR may occur late after transplantation. MMF is important to suppress the body's humoral response to allograft; when MMF was converted to a weaker immunosuppressant, the dose of the other immunosuppressants (cyclosporine for example) must be adjusted properly.     

A retrospective study of plasma cell infiltrates in explanted renal allografts

Renal transplantation is the most effective therapy in end-stage renal disease. The prognosis for transplant survival is still determined by rejection. When plasma cells predominate in the cellular infiltrate of allografts in rejection, it is called plasma cell-rich rejection, which has a poor prognosis. To study the correlation between plasma cell infiltration and humoral rejection, and to explore whether the local plasma cells were involved in renal allograft loss we analyzed 40 explanted grafts and 20 specimens removed for other diseases. All specimens were embedded, deparaffined, and stained with hematoxylin eosin (HE) for analysis by immunohistochemistry (IH). Renal allograft rejection was classified according to the Banff 1997 criteria with examinations for C4d deposition and CD138 expression. Positive C4d staining was defined by linear endothelial C4d deposition in > or =25% of cortical peritubular capillaries. The specimens designated as CD138-positive demonstrated strong and diffuse staining characteristics; trace or rare CD138-positive were classified as negative. Our results showed that among 40 renal graft specimens, 17 cases were C4d-positive, 23 cases were CD138-positive, and 13 cases were C4d and CD138 double-positive, namely, 42.5%, 57.5%, and 32.5%, respectively. Among the double-positive cases, there were 2 patients with a diagnosis of acute cellular rejection, 1 with hyperacute rejection, and 10 with chronic humoral rejection. C4d deposition and CD138-positive plasma cell infiltrate were related by a Spearman analysis (r = 0.330; P = .038). In the control group, there was only 1 case showing C4d positive activities. These observations suggested that infiltrated plasma cells in the renal allograft probably participate in humoral rejection through local secretion of antibodies.     

Effects of hypoxia-inducible factor-1alpha expression and C4d deposition in implantation biopsies on renal allograft

Upregulation of hypoxia-inducible factor-1alpha (HIF-1alpha) in response to ischemic states has been suggested to have a role in the development of chronic allograft nephropathy. Deposition of C4d in the peritubular capillaries of renal allografts has been reported to be a sensitive marker of acute humoral rejection. The purpose of this study was to determine the effects of HIF-1alpha expression and C4d deposition in implantation biopsies of renal allografts. Implantation biopsies and 22 rejection proved biopsies were performed in 54 renal transplant recipients between December 1996 and July 1999. The mean follow-up was 82.8 months. Immunohistochemical studies were performed using a mouse monoclonal antibody for HIF-1alpha expression and a rabbit polyclonal antibody for C4d detection. HIF-1alpha was demonstrated in 19 of 54 implantation biopsies (35%), and C4d deposition in one (1.9%). The HIF-1alpha-positive group included a higher percentage of deceased donor organs (66.4% vs 17.1%; P = .002) and longer mean cold ischemia times (261.3 +/- 231 vs 103 +/- 40 min; P = .008) compared with the HIF-1alpha-negative group. The relative risks (95% confidence intervals) of expression of HIF-1alpha for allograft rejection, chronic allograft nephropathy, and graft loss were 1.53 (0.82-2.87), 0.61 (0.06-5.50), and 2.45 (0.62-9.85). The C4d-positive patient developed acute accelerated rejection on postoperative day 4. In the present study, the expression of HIF-1alpha showed a significant correlation with the use of a deceased donor kidney and with cold ischemia time. However, there were no significant effects on the prognosis for a graft after implantation of a kidney with HIF-1alpha expression.