A rapid assay for on-site monitoring of infliximab trough levels: a feasibility study

Anal Bioanal Chem. 2013 Sep;405(23):7367-75. doi: 10.1007/s00216-013-7154-0. Epub 2013 Jul 9.

Abstract

Monitoring levels of biologicals against tumor necrosis factor (TNF) has been suggested to improve therapeutic outcomes in inflammatory bowel diseases (IBDs). This pilot study describes a rapid lateral flow (LF)-based assay for on-site monitoring of serum trough levels of humanized monoclonal antibody infliximab (IFX). The applied chromatographic method utilizes sequential flows of diluted serum, wash buffer, and an immunoglobulin generic label on LF strips with a Test line comprised of TNF-α. The successive flows permitted enrichment of IFX at the Test line before the label was applied. The label, luminescent upconverting phosphor (UCP) particles coated with protein-A, emits a 550-nm visible light upon excitation with 980-nm infrared light. IFX concentrations were determined through measurement of UCP fluorescence at the Test line. The assay was optimized to detect IFX levels as low as 0.17 μg/mL in serum. For patients with IBD, this limit is appropriate to detect levels associated with loss of response (0.5 μg IFX/mL). The assay was evaluated with clinical samples from patients with Crohn's disease and correlated well within the physiologically relevant range from 0.17 to 10 μg/mL with an IFX-specific ELISA. Performance of the assay was further successfully validated with samples from blood donors, IFX negative IBD patients, and rheumatoid arthritis patients that had developed anti-IFX antibodies. Because of its generic nature, the assay is suited for detecting most therapeutic anti-TNF-α monoclonal antibodies.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antibodies, Anti-Idiotypic / blood
  • Antibodies, Anti-Idiotypic / chemistry
  • Antibodies, Monoclonal / blood*
  • Antibodies, Monoclonal / therapeutic use
  • Arthritis, Rheumatoid / blood
  • Arthritis, Rheumatoid / immunology
  • Biological Assay / methods*
  • Biological Assay / standards
  • Crohn Disease / blood*
  • Crohn Disease / drug therapy
  • Crohn Disease / immunology
  • Feasibility Studies
  • Humans
  • Infliximab
  • Limit of Detection
  • Luminescent Measurements / methods*
  • Luminescent Measurements / standards
  • Phosphorus / chemistry
  • Protein Binding
  • Staining and Labeling
  • Staphylococcal Protein A / chemistry
  • Tumor Necrosis Factor-alpha / antagonists & inhibitors
  • Tumor Necrosis Factor-alpha / blood

Substances

  • Antibodies, Anti-Idiotypic
  • Antibodies, Monoclonal
  • Staphylococcal Protein A
  • Tumor Necrosis Factor-alpha
  • Phosphorus
  • Infliximab