PLoS ONE (Jan 2013)

An optimized immunohistochemistry technique improves NMO-IgG detection: study comparison with cell-based assays.

  • Romana Höftberger,
  • Lidia Sabater,
  • Romain Marignier,
  • Fahmy Aboul-Enein,
  • Raphaël Bernard-Valnet,
  • Helmut Rauschka,
  • Anne Ruiz,
  • Yolanda Blanco,
  • Francesc Graus,
  • Josep Dalmau,
  • Albert Saiz

DOI
https://doi.org/10.1371/journal.pone.0079083
Journal volume & issue
Vol. 8, no. 11
p. e79083

Abstract

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Cell-based assays (CBA) have increased the sensitivity of the neuromyelitis optica (NMO)-IgG/aquaporin-4-antibody detection compared to classical tissue-based indirect assays. We describe the sensitivity of an optimized immunohistochemistry (IHC-o) to detect NMO-IgG/aquaporin-4-antibody in comparison with that of two CBA: an in-house (CBA-ih) and a commercial (CBA-c) assay (Euroimmun, Germany). Coded serum from 103 patients with definite NMO and 122 inflammatory controls were studied by IHC-o, CBA-ih, and CBA-c. IHC-o used the same protocol described to detect antibodies against cell surface antigens. CBA-ih used live cells transfected with the aquaporin-4-M23-isoform. The sensitivity of the IHC-o was 74.8% (95% confidence interval [CI] 65-83) and was similar to that of the CBA-ih 75.7% (95% CI 66-84) and the CBA-c 73.8% (95% CI 64-82). The specificity of the three assays was 100% (95% CI 97-100). Interassay concordance was high, 100 of 103 samples were coincident in all techniques. The optimized immunohistochemistry proves to be as sensitive and specific as the cell-based assays. This assay extends the available tools for NMO-IgG/aquaporin-4-antibody detection.