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Springerplus. 2013 Jun 15;2(1):263. doi: 10.1186/2193-1801-2-263. Print 2013 Dec.

A simple set of validation steps identifies and removes false results in a sandwich enzyme-linked immunosorbent assay caused by anti-animal IgG antibodies in plasma from arthritis patients.

SpringerPlus

Tue W Kragstrup, Thomas Vorup-Jensen, Bent Deleuran, Malene Hvid

Affiliations

  1. Department of Biomedicine, Aarhus University, Wilhelm Meyers Allé 4, Aarhus C, DK-8000 Denmark.

PMID: 23875127 PMCID: PMC3695686 DOI: 10.1186/2193-1801-2-263

Abstract

Rheumatoid arthritis (RA) and spondyloarthritis (SpA) are chronic diseases characterized by activation of the immune system and production of antibodies. Thus, rheumatoid factor, anti-animal IgG antibodies and heterophilic antibodies in plasma samples from arthritis patients can interfere with immunoassays such as sandwich enzyme-linked immunosorbent assay (ELISA) systems often used in arthritis research. However, standard methodologies on how to test for false results caused by these antibodies are lacking. The objective of this study was to design a simple set of steps to validate a sandwich ELISA before using it for measuring analytes in plasma from arthritis patients. An interleukin-24 (IL-24) sandwich ELISA system was prepared with a monoclonal mouse capture antibody and a polyclonal goat detection antibody and tested for interference by rheumatoid factor, anti-animal IgG antibodies and heterophilic antibodies. Plasma samples from 23 patients with RA and SpA were used. No differences were found between plasma samples measured in wells coated with anti-IL-24 specific antibody and in wells coated with isotype control antibody (false positive results), and recombinant human IL-24 was not recovered in spiked samples (false negative results). This interference was removed after preincubating the plasma samples from patients with arthritis with goat or bovine IgG, suggesting that anti-animal IgG antibodies found in the plasma of the arthritis patients caused the false results. Additional testing showed that the signal-to-noise ratio could be increased by titration of the capture and detection antibodies and by using the ELAST amplification system. Finally, the calculated concentration of IL-24 was increased in ethylenediaminetetraacetic acid (EDTA) plasma compared to heparin plasma and serum and decreased with repetitive freeze/thaw cycles of the samples illustrating how sample handling could additionally contribute to the variations reported by different laboratories in measurement of the same analyte. This study proposes a simple set of validation steps to evaluate and optimize a sandwich ELISA before using it for measuring analytes in plasma from arthritis patients. Anti-animal IgG antibodies are also present in healthy individuals, suggesting that validation of ELISA systems for measuring non-arthritis samples could also be improved by this simple set of validation steps.

Keywords: Anti-animal IgG antibodies; Arthritis; ELAST amplification system; Enzyme-linked immunosorbent assay; Heterophilic antibodies; Immunoassay; Interference; Multiplex; Rheumatoid factor

References

  1. Arthritis. 2011;2011:741071 - PubMed
  2. Ann Clin Biochem. 1999 Nov;36 ( Pt 6):704-21 - PubMed
  3. Cytokine. 2008 Jan;41(1):16-23 - PubMed
  4. Arthritis Rheum. 1988 Mar;31(3):315-24 - PubMed
  5. APMIS. 2007 May;115(5):422-38; discussion 439 - PubMed
  6. J Immunoassay Immunochem. 2004;25(1):17-30 - PubMed
  7. Clin Exp Rheumatol. 2012 Jul-Aug;30(4):534-42 - PubMed
  8. J Immunol Methods. 1987 Jul 16;101(1):43-50 - PubMed
  9. Int Arch Allergy Appl Immunol. 1985;77(4):416-22 - PubMed
  10. Ann Clin Biochem. 2011 Sep;48(Pt 5):418-32 - PubMed
  11. J Immunol Methods. 2005 May;300(1-2):124-35 - PubMed
  12. BMC Immunol. 2009 Sep 28;10:52 - PubMed
  13. Cytokine Growth Factor Rev. 2010 Oct;21(5):381-91 - PubMed
  14. Scand J Immunol. 1978;8(1):21-8 - PubMed
  15. J Immunol. 2010 Oct 1;185(7):4154-68 - PubMed
  16. N Engl J Med. 2011 Dec 8;365(23):2205-19 - PubMed
  17. Mol Cell Proteomics. 2012 Feb;11(2):M9.00384 - PubMed
  18. Clin Chim Acta. 2002 Nov;325(1-2):1-15 - PubMed
  19. Lancet. 2011 Jun 18;377(9783):2127-37 - PubMed
  20. J Immunol Methods. 1989 Dec 20;125(1-2):279-85 - PubMed
  21. Arthritis Rheum. 1991 Oct;34(10):1218-27 - PubMed
  22. J Immunol Methods. 2010 Oct 31;362(1-2):70-81 - PubMed
  23. Vox Sang. 1980 Dec;39(6):339-42 - PubMed
  24. Gut. 1972 Oct;13(10):796-801 - PubMed
  25. Ann Clin Biochem. 2002 Jul;39(Pt 4):366-73 - PubMed
  26. Clin Exp Immunol. 1983 Feb;51(2):299-304 - PubMed
  27. Clin Diagn Lab Immunol. 2004 Mar;11(2):325-9 - PubMed
  28. Arthritis Rheum. 2011 Apr;63(4):894-903 - PubMed
  29. Annu Rev Immunol. 2011;29:71-109 - PubMed
  30. Immunol Rev. 2010 Jan;233(1):112-25 - PubMed
  31. Methods. 2013 May 15;61(1):18-22 - PubMed
  32. Clin Chem. 1999 Jul;45(7):942-56 - PubMed
  33. Lancet. 1991 Aug 24;338(8765):515-6 - PubMed
  34. J Immunol Methods. 2011 Sep 30;372(1-2):204-8 - PubMed
  35. Ann Rheum Dis. 1961 Sep;20:235-43 - PubMed

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