An optimized immunohistochemistry technique improves NMO-IgG detection: study comparison with cell-based assays.
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.
Service of Neurology, Hospital Clínic, Universitat de Barcelona and Institut d´Investigació Biomèdica August Pi i Sunyer (IDIBAPS), Barcelona, Spain ; Institute of Neurology, Medical University of Vienna, Vienna, Austria.
Romana
R
Höftberger
Lidia
L
Sabater
Romain
R
Marignier
Fahmy
F
Aboul-Enein
Raphaël
R
Bernard-Valnet
Helmut
H
Rauschka
Anne
A
Ruiz
Yolanda
Y
Blanco
Francesc
F
Graus
Josep
J
Dalmau
Albert
A
Saiz
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000818:Animals; D051401:Aquaporin 4 / Q000276:immunology; D001323:Autoantibodies / Q000032:analysis / Q000276:immunology; D002648:Child; D005260:Female; D019084:Fluorescent Antibody Technique, Indirect / Q000379:methods*; D006801:Humans; D007074:Immunoglobulin G / Q000032:analysis* / Q000276:immunology; D007150:Immunohistochemistry / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009471:Neuromyelitis Optica / Q000175:diagnosis* / Q000276:immunology; D051381:Rats; D017207:Rats, Sprague-Dawley; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D055815:Young Adult
D051401:Aquaporin 4; D001323:Autoantibodies; D007074:Immunoglobulin G