1
|
Afonso J, Lopes S, Gonçalves R, Caldeira P, Lago P, Tavares de Sousa H, Ramos J, Gonçalves AR, Ministro P, Rosa I, Vieira AI, Coelho R, Tavares P, Soares J, Sousa AL, Carvalho D, Sousa P, da Silva JP, Meira T, Silva Ferreira F, Dias CC, Chowers Y, Ben-Horin S, Magro F. Detection of anti-infliximab antibodies is impacted by antibody titer, infliximab level and IgG4 antibodies: a systematic comparison of three different assays. Therap Adv Gastroenterol 2016; 9:781-794. [PMID: 27803733 PMCID: PMC5076767 DOI: 10.1177/1756283x16658223] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
BACKGROUND There is scant information on the accuracy of different assays used to measure anti-infliximab antibodies (ADAs), especially in the presence of detectable infliximab (IFX). We thus aimed to evaluate and compare three different assays for the detection of IFX and ADAs and to clarify the impact of the presence of circulating IFX on the accuracy of the ADA assays. METHODS Blood samples from 79 ulcerative colitis (UC) patients treated with infliximab were assessed for IFX levels and ADAs using three different assays: an in-house assay and two commercial kits, Immundiagnostik and Theradiag. Sera samples with ADAs and undetectable levels of IFX were spiked with exogenous IFX and analyzed for ADAs. RESULTS The three assays showed 81-96% agreement for the measured IFX level. However, the in-house assay and Immundiagnostik assays detected ADAs in 34 out of 79 samples, whereas Theradiag only detected ADAs in 24 samples. Samples negative for ADAs with Theradiag, but ADA-positive in both the in-house and Immundiagnostik assays, were positive for IFX or IgG4 ADAs. In spiking experiments, a low concentration of exogenous IFX (5 µg/ml) hampered ADA detection with Theradiag in sera samples with ADA levels of between 3 and 10 µg/ml. In the Immundiagnostik assay detection interference was only observed at concentrations of exogenous IFX higher than 30 µg/ml. However, in samples with high levels of ADAs (>25 µg/ml) interference was only observed at IFX concentrations higher than 100 µg/ml in all three assays. Binary (IFX/ADA) stratification of the results showed that IFX+/ADA- and IFX-/ADAs+ were less influenced by the assay results than the double-positive (IFX+/ADAs+) and double-negative (IFX-/ADAs-) combination. CONCLUSIONS All three methodologies are equally suitable for measuring IFX levels. However, erroneous therapeutic decisions may occur when patients show double-negative (IFX-/ADAs-) or double-positive (IFX+/ADAs+) status, since agreement between assays is significantly lower in these circumstances.
Collapse
Affiliation(s)
- Joana Afonso
- Department of Pharmacology and Therapeutics, Faculty of Medicine, University of Porto, Porto, Portugal MedInUP, Centre for Drug Discovery and Innovative Medicines, University of Porto, 4200 Porto, Portugal
| | - Susana Lopes
- Gastroenterology Department, Centro Hospitalar São João, Porto, Portugal
| | | | - Paulo Caldeira
- Gastroenterology Department, Centro Hospitalar do Algarve, Faro, Portugal
| | - Paula Lago
- Gastroenterology Department, Centro Hospitalar do Porto, Porto, Portugal
| | - Helena Tavares de Sousa
- Gastroenterology Department, Centro Hospitalar do Algarve, Portimão, Portugal Departament of Medicine e Medical Biosciences, University of Algarve, Faro, Portugal
| | - Jaime Ramos
- Gastroenterology Department, Centro Hospitalar de Lisboa, Lisboa, Portugal
| | - Ana Rita Gonçalves
- Gastroenterology Department, Centro Hospitalar Lisboa Norte, Lisboa, Portugal
| | - Paula Ministro
- Gastroenterology Department, Hospital de S. Teotónio, Viseu, Portugal
| | - Isadora Rosa
- Gastroenterology Department, Instituto Português de Oncologia de Lisboa, Lisboa, Portugal
| | - Ana Isabel Vieira
- Gastroenterology Department, Hospital Garcia de Orta, Almada, Portugal
| | - Rosa Coelho
- Gastroenterology Department, Centro Hospitalar São João, Porto, Portugal
| | - Patrícia Tavares
- Gastroenterology Department, Centro Hospitalar São João, Porto, Portugal
| | - João Soares
- Gastroenterology Department, Hospital de Braga, Braga, Portugal
| | - Ana Lúcia Sousa
- Gastroenterology Department, Centro Hospitalar do Algarve, Faro, Portugal
| | - Diana Carvalho
- Gastroenterology Department, Centro Hospitalar de Lisboa, Lisboa, Portugal
| | - Paula Sousa
- Gastroenterology Department, Hospital de S. Teotónio, Viseu, Portugal
| | - João Pereira da Silva
- Gastroenterology Department, Instituto Português de Oncologia de Lisboa, Lisboa, Portugal
| | - Tânia Meira
- Gastroenterology Department, Hospital Garcia de Orta, Almada, Portugal
| | - Filipa Silva Ferreira
- Department of Pharmacology and Therapeutics, Faculty of Medicine, University of Porto, Porto, Portugal MedInUP, Centre for Drug Discovery and Innovative Medicines, University of Porto, 4200 Porto, Portugal
| | - Cláudia Camila Dias
- Department of Pharmacology and Therapeutics, Faculty of Medicine, University of Porto, Porto, Portugal
| | - Yehuda Chowers
- Gastroenterology Department, Rambam Health Care Campus and Bruce Rappaport School of Medicine, Technion Israel Institute of Technology, Israel
| | - Shomron Ben-Horin
- IBD Service, Department of Gastroenterology, Sheba Medical Center and Sackler School of Medicine, Tel-Aviv University, Israel
| | | | | |
Collapse
|