Seroprevalence of NMO-IgG antibody in Brazilian patients with neuromyelitis optica

Abstract

-Neuromyelitis optica (NMO; Devic's disease) and its spectrum disorders are idiopathic inflammatory demyelinating diseases of the central nervous system (CNS) that mainly affect the optic nerves and spinal cord 1 . The hallmark of NMO pathology is the presence of necrotic spinal cord lesions involving both gray and white matter, often resulting in cavitation, as well as the presence of vascular hyalinization 2 . NMO and multiple sclerosis (MS) are currently considered different diseases since the description of NMO-IgG, a serum gamma immunoglobulin autoantibody that is a specific marker for NMO 3,4 . NMO-IgG selectively binds to aquaporin-4 (AQP4) water channel, a component of the dystroglycan protein complex of astrocytic foot processes at the blood-brain barrier 5 . Its sensitivity and specificity for NMO diagnosis were confirmed in several studies and the presence of NMO-IgG is now one of the new diagnostic criteria for neuromyelitis optica 4 .NMO may represent the first example of a novel class of autoimmune channelopathy 5 . The clinical course of NMO is usually more severe than of MS. Within five years of onset, fifty percent of patients either lose functional vision in at least one eye or become unable to walk unassisted 6 . Detection of the autoantibody enables early diagnosis of NMO, before the presence of a full-blown clinical picture, allowing early initiation of appropriate immunosuppressive therapy. This is the first study of frequency of NMO-IgG in a series of Brazilian relapsing NMO patients. METHODTwenty-eight patients with NMO from the Center for Myelin Disorders of the Neurologic Clinic of São Paulo University School of Medicine, São Paulo, Brazil, were enrolled. All of them fulfilled the original criteria for diagnosis of NMO 6 . Demographic and clinical characteristics of patients included in our study are shown on Table 1. Briefly, median age at onset of disease was 27 years (range 7-51), median time of follow-up was 8 years (range 1-14). The mean time elapsed between optic neuritis and myelitis was 18 months (median 21; range 2-60), Kurtzke's Expanded Disease Severity Score on last visit was 6.0 (range 2-8).

Neuromyelitis optica: phenotypic characteristics in a Brazilian case series

“…In the present case series, AQP4-IgG seropositivity was similar to that reported by Lennon et al 4 (73%) and was higher than that found by Adoni et al 23 in Brazilian patients with recurrent NMO; both studies used the IF method.…”

Neuromyelitis optica antibody in Leber hereditary optic neuropathy: case report

“…In Brazil, the seroprevalence of anti-AQP4 test in NMO or hi ghrisk syndrome for NMO patients was first reported in 2008 and the seropositivity in this group was 64.3%. This finding was similar to that observed in other countries (6) . Conversely, LHON is an mtDNA mutation disease whose clinical setting is confined to the optic nerve and, eventually, the spinal cord (7) .…”

The expanded spectrum of neuromyelitis optica: evidences for a new definition

“…Sensitivity and specificity were 73 and 91% for NMO and 58 and 100% for OSMS, whereas the antibody was found in 50% of patients with high-risk syndromes 9 . The serum antibody has been variably detected in different populations 22 . Currently available assays include a tissue-based indirect immunofluorescence (IIF) assay; ELISA; fluorescence immunoprecipitation assay (FIPA) 23,24 ; fluorescence-activated cell sorting (FACS) assay; and visual fluorescence-observation cell-based assay (CBA) [24][25][26] .…”