Willrich Maria Alice V, Lazar-Molnar Eszter, Snyder Melissa R, Delgado Julio C
Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN.
ARUP Laboratories, Department of Pathology, University of Utah School of Medicine, Salt Lake City, UT.
J Appl Lab Med. 2018 May 1;2(6):893-903. doi: 10.1373/jalm.2017.024869.
Infliximab (IFX) is a chimeric monoclonal antibody targeting tumor necrosis factor-α, used for the management of autoimmune and inflammatory diseases. Immunogenicity to this protein drug may lead to therapeutic failure. Laboratory testing for serum IFX and antidrug antibodies (ADAs) is available for the evaluation of clinical nonresponsiveness. The purpose of this study was to compare the performance of testing methodologies used by 2 clinical reference laboratories for the quantification of IFX and detection of ADAs.
Deidentified serum samples submitted for clinical testing were selected (n = 120) and tested at both sites. A trypsin-based LC-MS/MS assay for IFX and a bridging electrochemiluminescent immunoassay (ECLIA) for ADAs (Mayo Clinic) and a functional cell-based reporter gene assay (RGA) to measure both bioactive drug concentrations and neutralizing ADAs (ARUP Laboratories) were compared.
In all, 105 samples had measurable concentrations of IFX by both methods and yielded a correlation coefficient (r) = 0.917, slope = 1.028, and intercept = -0.377. One outlier measured <1.0 μg/mL by LC-MS/MS and 37 μg/mL by RGA, which was confirmed to be attributed to the presence of adalimumab. Regarding detection of ADAs, 81 of 120 samples were negative by ECLIA and RGA, whereas 30 of 120 were positive by both methods, resulting in an overall 92.5% agreement.
Although there are substantial methodological differences in the assays used for detecting IFX and ADAs, results show significant concordance between the clinically validated methodologies performed in different laboratories.
英夫利昔单抗（IFX）是一种靶向肿瘤坏死因子-α的嵌合单克隆抗体，用于治疗自身免疫性疾病和炎症性疾病。这种蛋白质药物的免疫原性可能导致治疗失败。血清IFX和抗药物抗体（ADA）的实验室检测可用于评估临床无反应性。本研究的目的是比较两家临床参考实验室用于定量IFX和检测ADA的检测方法的性能。
选择提交进行临床检测的匿名血清样本（n = 120），并在两个实验室进行检测。比较了一种基于胰蛋白酶的IFX液相色谱-串联质谱（LC-MS/MS）检测方法、一种用于ADA的桥接电化学发光免疫分析（ECLIA，梅奥诊所）和一种基于功能细胞的报告基因分析（RGA，用于测量生物活性药物浓度和中和性ADA，ARUP实验室）。
总体而言，105个样本通过两种方法均检测到可测量浓度的IFX，相关系数（r） = 0.917，斜率 = 1.028，截距 = -0.377。一个异常值通过LC-MS/MS测得<1.0 μg/mL，通过RGA测得37 μg/mL，经确认这是由于存在阿达木单抗所致。关于ADA的检测，120个样本中有81个通过ECLIA和RGA检测为阴性，而120个样本中有30个通过两种方法均检测为阳性，总体一致性为92.5%。
尽管用于检测IFX和ADA的检测方法存在很大的方法学差异，但结果显示不同实验室进行的临床验证方法之间具有显著的一致性。
