Western blot analysis for the detection of serum antibodies recognizing linear Aquaporin-4 epitopes in patients with Neuromyelitis Optica

Received 10 June 2009; received in revised form 29 September 2009; accepted 2 October 2009. published online 22 October 2009.

Abstract

The current study presents a western blot assay showing good sensitivity (81%) and specificity (97%) for detecting serum antibodies to Aquaporin-4 (AQP4) in patients with Neuromyelitis Optica (NMO). By using western blot, we were able, for the first time, to distinguish serum immunoreactivity against either of the two AQP4 isoforms, showing that antibodies recognizing the linear AQP4-M1 isoform are specific for NMO. Moreover, the high sensitivity and specificity of the western blot assay in detecting serum anti-AQP4 antibodies in NMO patients suggest that such auto-antibodies may be of linear nature, thus recognizing epitopes that are displayed in denatured protein.

Keywords: Aquaporin-4, Neuromyelitis Optica, AQP-4 antibodies

a SCDO: Neurologia 2, Centro Sclerosi Multipla (CReSM), AOU S. Luigi Gonzaga, Orbassano, Torino, Italy

b Istituto scientifico Cavalieri Ottolenghi, Università degli studi di Torino, AOU S. Luigi Gonzaga, Orbassano, Torino, Italy

c Centro Sclerosi Multipla, Dipartimento di Scienze Neurologiche e Cardiovascolari, Università degli Studi di Cagliari, Cagliari, Italy

d Centro Sclerosi Multipla, Dipartimento di Neuroscienze, Policlinico Universitario Agostino Gemelli, UCSC Rome, Italy

e Department of Neurology, Charles University in Prague, 1st Faculty of Medicine and General Teaching Hospital, Prague, Czech Republic

Corresponding author. SCDO: Neurologia 2, Centro Sclerosi Multipla (CReSM), AOU S. Luigi Gonzaga, Regione Gonzole 10, I-10043, Orbassano, Torino, Italy. Tel.: +39 011 9026437; fax: +39 011 9026397.

PII: S0165-5728(09)00393-2

doi:10.1016/j.jneuroim.2009.10.002

15 of 21