Teixeira Fábio Vieira, Sassaki Ligia Yukie, Saad-Hossne Rogerio, Baima Julio Pinheiro, Magro Daniéla Oliveira, Coy Claudio Saddy Rodrigues, Kotze Paulo Gustavo
Clínica GastroSaúde, Marília, SP, Brasil.
Universidade Estadual Paulista (UNESP), Campus de Botucatu, Ambulatório de Doenças Inflamatóticas Intestinais, Faculdade de Medicina, Botucatu, SP, Brasil.
Arq Gastroenterol. 2018 Apr-Jun;55(2):192-197. doi: 10.1590/S0004-2803.201800000-35.
Infliximab (IFX) therapeutic drug monitoring is an important tool to guide therapeutic decision in inflammatory bowel disease patients. Currently, there are two methods to measure trough levels of IFX, ELISA assays or rapid tests. Despite that the ELISA assay is the most used method in therapeutic drug monitoring, the results take long to be available for clinical use, and it needs to be performed by trained personnel. In contrary, the results of a rapid test take 20 to 30 minutes to be available and can be performed by non-trained lab personnel.
The aim of the study was to compare a rapid test (QB-IFX) for quantitative determination of IFX level to one ELISA assay in a cohort of inflammatory bowel disease patients.
Cross-sectional multicentric study with 49 inflammatory bowel disease patients on maintenance therapy with IFX. Blood samples for IFX serum levels were collected immediately before infusion. IFX serum levels were classified as undetectable, low (<3.0 μg/mL), adequate (3.1-7.0 μg/mL) or high (>7.1 μg/mL). A sensitivity and specificity of each test and a comparison between tests was based on ROC curves.
Thirty-four Crohn's disease patients and 15 ulcerative colitis patients in clinical remission were evaluated. The majority of patients had low or adequate serum levels of IFX. In relation to the serum levels proportions with the two methods, there was no significant difference (P=0.84). The ROC analysis identified a concentration threshold >2.9 μg/mL with the QB-IFX test (area under the ROC, 0.82; P<0.0001, sensitivity, 100%; specificity, 61.9%), and >3.83 μg/mL using the ELISA assay (area under the ROC, 0.96; P<0.0001, sensitivity, 100%; specificity, 92.9%).
QB-IFX and ELISA assays to measure IFX levels were comparable. Both methods had accurate sensitivity and specificity to detect undetectable, low and adequate levels, but had showed low specificity for supra therapeutic levels of IFX.
英夫利昔单抗（IFX）治疗药物监测是指导炎症性肠病患者治疗决策的重要工具。目前，有两种方法可测量IFX的谷浓度，即酶联免疫吸附测定（ELISA）法或快速检测法。尽管ELISA法是治疗药物监测中最常用的方法，但其结果需要很长时间才能用于临床，且需要由经过培训的人员进行操作。相反，快速检测的结果在20至30分钟内即可获得，且可由未经培训的实验室人员进行操作。
本研究旨在比较一种用于定量测定IFX水平的快速检测法（QB-IFX）与一种ELISA法在一组炎症性肠病患者中的应用。
对49例接受IFX维持治疗的炎症性肠病患者进行横断面多中心研究。在输液前立即采集血样以检测IFX血清水平。IFX血清水平分为不可检测、低（<3.0μg/mL）、适宜（3.1-7.0μg/mL）或高（>7.1μg/mL）。基于受试者工作特征（ROC）曲线分析每种检测方法的敏感性和特异性，并对两种检测方法进行比较。
对34例克罗恩病患者和15例临床缓解期的溃疡性结肠炎患者进行了评估。大多数患者的IFX血清水平较低或适宜。就两种方法的血清水平比例而言，差异无统计学意义（P=0.8）。ROC分析确定QB-IFX检测的浓度阈值>2.9μg/mL（ROC曲线下面积为0.82；P<0.0001，敏感性为100%；特异性为61.9%），ELISA法的浓度阈值>3.83μg/mL（ROC曲线下面积为0.96；P<0.0001，敏感性为100%；特异性为92.9%）。
QB-IFX和ELISA法在测量IFX水平方面具有可比性。两种方法在检测不可检测、低和适宜水平时均具有准确的敏感性和特异性，但对IFX超治疗水平的特异性较低。
