Thoren Katie L, Pasi Brian, Delgado Julio C, Wu Alan H B, Lynch Kara L
Department of Laboratory Medicine, University of California San Francisco, San Francisco, CA.
ARUP Laboratories, Inc., University of Utah School of Medicine, Salt Lake City, UT.
J Appl Lab Med. 2018 Mar 1;2(5):725-736. doi: 10.1373/jalm.2017.024380.
Monitoring infliximab (IFX) concentrations and the presence of antidrug antibodies (ADA) is important for patient management. We developed a method to measure IFX and ADA in serum in a single injection using surface plasmon resonance (SPR).
Using the Bio-Rad ProteOn XPR36, tumor necrosis factor-α and IFX were covalently immobilized onto separate lanes of a chip surface. Diluted serum was injected over both lanes, followed by an injection of goat antihuman antibody. The binding response was used to quantify IFX or detect ADA. The analytical performance of the assay was determined. Using 50 patient samples, SPR results were compared with results from a reporter gene assay (RGA).
For the quantification of IFX, the functional sensitivity was 0.5 μg/mL. The total precision was <10% for all concentrations tested. IFX concentrations measured by SPR correlated well with RGA (R = 0.862), but a bias was observed (slope = 0.61). SPR detected 14 ADA-positive samples. Compared with RGA for ADA detection, there were 6 true-positive, 8 false-positive, 5 false-negative, and 31 true-negative findings.
SPR can be used to measure biological drug concentrations and detect ADA in serum. This technique may provide complementary information to current methods used to detect ADA.
监测英夫利昔单抗（IFX）浓度及抗药抗体（ADA）的存在情况对患者管理很重要。我们开发了一种利用表面等离子体共振（SPR）单次进样测量血清中IFX和ADA的方法。
使用伯乐ProteOn XPR36，将肿瘤坏死因子-α和IFX共价固定在芯片表面的不同通道上。将稀释后的血清注入两个通道，随后注入山羊抗人抗体。结合反应用于定量IFX或检测ADA。确定了该检测方法的分析性能。使用50份患者样本，将SPR结果与报告基因检测（RGA）结果进行比较。
对于IFX的定量，功能灵敏度为0.5μg/mL。在所有测试浓度下，总精密度<10%。通过SPR测量的IFX浓度与RGA相关性良好（R = 0.862），但观察到有偏差（斜率 = 0.61）。SPR检测到14份ADA阳性样本。与RGA检测ADA相比，有6例假阳性、8例假阴性、5例假阳性和31例真阴性结果。
SPR可用于测量生物药物浓度并检测血清中的ADA。该技术可为当前用于检测ADA的方法提供补充信息。
