Journal Article

Antiacquaporin 4 antibodies detection by different techniques in neuromyelitis optica patients

Privitera, D., Ghezzi, A., Lampasona, V., Marnetto, F., De Feo, D., Fazio, R., Malosio, ML, Centonze, D., Martino, G., Comi, G., Furlan, R.

2009

Overview

Background: Antibodies against aquaporin-4 (AQP4), a water channel particularly expressed on perivascular astrocytic podocytes, are proposed as a marker for the diagnosis of neuromyelitis optica (NMO). However, a consensus on seroprevalence and optimal detection method has not yet been reached. Objectives: To investigate the performance of different assays to detect anti-AQP4 antibodies. Methods: We set up five different assays. Two of them were capable to detect perivascular IgG reactivity on brain tissue by immunofluorescence (NMO-IgG). Other three assays have been set to detect anti-AQP4 antibodies: immunofluorescence and flow cytometry on AQP4-expressing cells, and a radioimmunoprecipitation assay. We assessed sensitivity and specificity of these assays by interrogating sera of 33 NMO patients, 13 patients at high risk to develop NMO (hrNMO), 6 patients affected by acute partial transverse myelitis (APTM), 20 patients with multiple sclerosis (MS), and 67 age- and sex-matched healthy controls. Results: We found that the presence of serum NMO-IgG and anti-AQP4 reactivity is almost exclusively restricted to patients with NMO and hrNMO. Seroprevalence and sensitivity ranged from 30 to 47%, depending on the assay. Specificity ranged from 95 to 100%. Comparing results obtained in the five assays, we noticed lack of concordance in some samples. Conclusions: Detection of NMO-IgG or anti-AQP4 antibodies may represent a valuable tool to assist neurologists in the differential diagnosis between patients with NMO, hrNMO, APTM, or MS. The current lack of a gold standard to detect anti-AQP4 antibodies implies the necessity to standardize the detection of these antibodies.

• Publisher: SAGE Publications,Sage Publications,Sage Publications Ltd
• Subject: Adolescent / Adult / Aged / Antibody Specificity / Aquaporin 4 - immunology / Autoantibodies - analysis / Autoantibodies - blood / Biological and medical sciences / Brain - immunology / Child / Cohort Studies / Degenerative and inherited degenerative diseases of the nervous system. Leukodystrophies. Prion diseases / Diagnosis, Differential / Female / Flow Cytometry / Fluorescent Antibody Technique / Humans / Immunoglobulin G - analysis / Male / Medical sciences / Middle Aged / Multiple Sclerosis - diagnosis / Multiple Sclerosis - immunology / Multiple sclerosis and variants. Guillain barré syndrome and other inflammatory polyneuropathies. Leukoencephalitis / Myelitis, Transverse - diagnosis / Myelitis, Transverse - immunology / Neurology / Neuromyelitis Optica - blood / Neuromyelitis Optica - diagnosis / Neuromyelitis Optica - etiology / Neuromyelitis Optica - immunology / Radioimmunoprecipitation Assay / Risk Factors / Sensitivity and Specificity / Seroepidemiologic Studies / Young Adult