Epidemiology of Aquaporin-4 Autoimmunity and Neuromyelitis Optica Spectrum: A Comparison of Two Ethnically Divergent Populations (P3.003)

Objective: We sought to compare the seroepidemiology of neuromyelitis optica and its spectrum disorders (NMOSD) across two ethnically divergent populations. Background: NMO/NMOSD are inflammatory demyelinating diseases (IDD) with a specific biomarker, aquaporin-4-IgG. Prior NMO/NMOSD epidemiological studies are limited by lack of aquaporin-4-IgG seroprevalence assessment, absence of population-based USA studies and under-representation of blacks. Methods: We performed a population-based comparative study of the incidence (2003-2011) and prevalence (on December 31, 2011) of NMO/NMOSD and aquaporin-4-IgG seroincidence and seroprevalence (sera collected in 80-84[percnt] of IDD) among patients with IDD diagnosis in Olmsted County, USA (82[percnt] white [Caucasian]) and Martinique (90[percnt] black [Afro-Caribbean]). Aquaporin-4-IgG was measured by M1-isoform-fluorescent-activated-cell-sorting assays. Results: The incidence (7.6 vs 0.8/1,000,000 person-years [p<0.01]) and prevalence (9.9 vs 4.1/100,000[p=0.04]) in Martinique exceeded that in Olmsted County. The AQP4-IgG seroincidence (6.8 vs 0.8/1,000,000 person-years [p=0.01]) and seroprevalence (7.9 vs 3.4/100,000[p=0.09]) was also higher in Martinique than Olmsted County. The ethnicity-specific prevalence was similar in Martinique and Olmsted County: 10.8 and 12.6/100,000 in blacks, and 5.1 and 4.1/100,000 in whites, respectively. NMO/NMOSD represented a higher proportion of IDD in Martinique than Olmsted County (16[percnt] vs 1.4[percnt]; p<0.01). The onset age (median, 35-37 years) and female:male distribution (8-9:1) were similar across both populations; 60[percnt] of prevalent cases were either blind in one eye, dependent on a gait aid or both. Conclusions: This study reports the highest prevalence of NMO/NMOSD in any population (9.9/100,000 in Martinique), estimates it affects 16,000-17,000 in the USA (higher than previous predictions) and demonstrates it disproportionately affects blacks. Disclosure: Dr. Flanagan has nothing to disclose. Dr. P. Cabre has received personal compensation for activities with Biogen Idec, EMD Serono and Novartis as consultant. Dr. Weinshenker has received personal compensation for activities with Novartis, Biogen Idec, Mitsubishi Pharmaceuticals, MedImmune Pharmaceuticals, Chugai, and Chord as a consultant. Dr. Weinshenker has received royalty payments from RSR Ltd. and Oxford Dr. St. Sauver has nothing to disclose. Dr. Majed has nothing to disclose. Dr. Lennon has received research support from the National Institutes of Health. Dr. Lucchinetti stands to receive royalty payments for commercial assays. Dr. McKeon has received research support from Medimmune. Dr. Wingerchuk has received personal compensation for serving on a clinical trial adjudication committee for Medimmune. Dr. Wingerchuk has received personal compensation in an editorial capacity for The Neurologist. Dr. Wingerchuk has received research su Dr. Mandrekar has nothing to disclose. Dr. Jacobson has nothing to disclose. Dr. Sagen has nothing to disclose. Dr. Schmeling has nothing to disclose. Dr. Fryer has nothing to disclose. Dr. Matiello has nothing to disclose. Dr. Kale has nothing to disclose. Dr. Borders Robinson has nothing to disclose. Dr. Pittock has received (royalty or license fee or contractual rights) payments from Peripherin-Specific Autoantibodies as a Marker for Neurological and Endocrinological Disease.