National Transplant Services, Australian Red Cross Blood Service, Melbourne, Victoria, Australia.
Transplantation. 2013 Jan 15;95(1):19-47. doi: 10.1097/TP.0b013e31827a19cc.
The introduction of solid-phase immunoassay (SPI) technology for the detection and characterization of human leukocyte antigen (HLA) antibodies in transplantation while providing greater sensitivity than was obtainable by complement-dependent lymphocytotoxicity (CDC) assays has resulted in a new paradigm with respect to the interpretation of donor-specific antibodies (DSA). Although the SPI assay performed on the Luminex instrument (hereafter referred to as the Luminex assay), in particular, has permitted the detection of antibodies not detectable by CDC, the clinical significance of these antibodies is incompletely understood. Nevertheless, the detection of these antibodies has led to changes in the clinical management of sensitized patients. In addition, SPI testing raises technical issues that require resolution and careful consideration when interpreting antibody results.
With this background, The Transplantation Society convened a group of laboratory and clinical experts in the field of transplantation to prepare a consensus report and make recommendations on the use of this new technology based on both published evidence and expert opinion. Three working groups were formed to address (a) the technical issues with respect to the use of this technology, (b) the interpretation of pretransplantation antibody testing in the context of various clinical settings and organ transplant types (kidney, heart, lung, liver, pancreas, intestinal, and islet cells), and (c) the application of antibody testing in the posttransplantation setting. The three groups were established in November 2011 and convened for a "Consensus Conference on Antibodies in Transplantation" in Rome, Italy, in May 2012. The deliberations of the three groups meeting independently and then together are the bases for this report.
A comprehensive list of recommendations was prepared by each group. A summary of the key recommendations follows. Technical Group: (a) SPI must be used for the detection of pretransplantation HLA antibodies in solid organ transplant recipients and, in particular, the use of the single-antigen bead assay to detect antibodies to HLA loci, such as Cw, DQA, DPA, and DPB, which are not readily detected by other methods. (b) The use of SPI for antibody detection should be supplemented with cell-based assays to examine the correlations between the two types of assays and to establish the likelihood of a positive crossmatch (XM). (c) There must be an awareness of the technical factors that can influence the results and their clinical interpretation when using the Luminex bead technology, such as variation in antigen density and the presence of denatured antigen on the beads. Pretransplantation Group: (a) Risk categories should be established based on the antibody and the XM results obtained. (b) DSA detected by CDC and a positive XM should be avoided due to their strong association with antibody-mediated rejection and graft loss. (c) A renal transplantation can be performed in the absence of a prospective XM if single-antigen bead screening for antibodies to all class I and II HLA loci is negative. This decision, however, needs to be taken in agreement with local clinical programs and the relevant regulatory bodies. (d) The presence of DSA HLA antibodies should be avoided in heart and lung transplantation and considered a risk factor for liver, intestinal, and islet cell transplantation. Posttransplantation Group: (a) High-risk patients (i.e., desensitized or DSA positive/XM negative) should be monitored by measurement of DSA and protocol biopsies in the first 3 months after transplantation. (b) Intermediate-risk patients (history of DSA but currently negative) should be monitored for DSA within the first month. If DSA is present, a biopsy should be performed. (c) Low-risk patients (nonsensitized first transplantation) should be screened for DSA at least once 3 to 12 months after transplantation. If DSA is detected, a biopsy should be performed. In all three categories, the recommendations for subsequent treatment are based on the biopsy results.
A comprehensive list of recommendations is provided covering the technical and pretransplantation and posttransplantation monitoring of HLA antibodies in solid organ transplantation. The recommendations are intended to provide state-of-the-art guidance in the use and clinical application of recently developed methods for HLA antibody detection when used in conjunction with traditional methods.
固相免疫测定（SPI）技术的引入，为移植中人类白细胞抗原（HLA）抗体的检测和特征分析提供了更高的灵敏度，优于补体依赖性细胞毒性（CDC）检测。这一技术的应用，对供体特异性抗体（DSA）的解读带来了新的模式。尽管在 Luminex 仪器上进行的 SPI 检测（以下简称 Luminex 检测），特别是能够检测到 CDC 无法检测到的抗体，但这些抗体的临床意义尚未完全了解。尽管如此，这些抗体的检测已经导致了对致敏患者临床管理的改变。此外，SPI 检测提出了一些技术问题，在解释抗体结果时需要加以解决和认真考虑。
在此背景下，移植学会召集了一组实验室和临床领域的专家，基于已发表的证据和专家意见，准备了一份共识报告，并就这项新技术的应用提出建议。成立了三个工作组，分别解决（a）使用这项技术的技术问题，（b）各种临床环境和器官移植类型（肾、心、肺、肝、胰腺、肠和胰岛细胞）下的移植前抗体检测的解读，以及（c）抗体检测在移植后的应用。这三个小组于 2011 年 11 月成立，并于 2012 年 5 月在意大利罗马举行了“移植抗体共识会议”。三个小组独立和共同的审议是本报告的基础。
每个小组都准备了一份全面的建议清单。以下是关键建议的摘要。技术组：（a）SPI 必须用于检测实体器官移植受者的移植前 HLA 抗体，特别是使用单抗原珠检测来检测 HLA 位点的抗体，如 Cw、DQA、DPA 和 DPB，这些抗体不易用其他方法检测。（b）应使用 SPI 进行抗体检测，并辅以细胞检测，以检查两种检测方法之间的相关性，并确定阳性交叉配型（XM）的可能性。（c）在使用 Luminex 珠技术时，必须了解可能影响结果及其临床解释的技术因素，如抗原密度的变化和珠上变性抗原的存在。移植前组：（a）应根据抗体和获得的 XM 结果建立风险类别。（b）应避免 CDC 检测到的 DSA 和阳性 XM，因为它们与抗体介导的排斥反应和移植物丢失有很强的关联。（c）如果所有 HLA Ⅰ类和Ⅱ类位点的单抗原珠筛选均为阴性，则可以在没有前瞻性 XM 的情况下进行肾移植。然而，这一决定需要与当地的临床项目和相关监管机构达成一致。（d）心脏和肺移植应避免存在 DSA HLA 抗体，并将其视为肝、肠和胰岛细胞移植的危险因素。移植后组：（a）高风险患者（即脱敏或 DSA 阳性/XM 阴性）应在移植后 3 个月内通过测量 DSA 和协议活检进行监测。（b）中风险患者（有 DSA 但目前阴性的病史）应在第一个月内监测 DSA。如果存在 DSA，则应进行活检。（c）低风险患者（首次非致敏移植）应在移植后 3 至 12 个月内至少筛查一次 DSA。如果检测到 DSA，则应进行活检。在所有三个类别中，后续治疗的建议都基于活检结果。
本共识报告提供了一份涵盖实体器官移植中 HLA 抗体的技术和移植前及移植后监测的全面建议清单。这些建议旨在提供在使用最近开发的 HLA 抗体检测方法时的最新指导，这些方法与传统方法结合使用。
