Heterogeneity of aquaporin-4 autoimmunity and spinal cord lesions in multiple sclerosis in Japanese

Abstract

Opticospinal multiple sclerosis (OSMS) in Asians has similar features to the relapsing-remitting form of neuromyelitis optica (NMO) seen in Westerners. OSMS is suggested to be NMO based on the frequent detection of specific IgG targeting aquaporin-4 (AQP4), designated NMO-IgG. The present study sought to clarify the significance of anti-AQP4 autoimmunity in the whole spectrum of MS. Sera from 113 consecutive Japanese patients with clinically definite MS, based on the Poser criteria, were assayed for anti-AQP4 antibodies by immunofluorescence using GFP-AQP4 fusion protein-transfected HEK-293T cells. Sensitivity and specificity of the anti-AQP4 antibody assay, 83.3 and 100%, respectively, were calculated using serum samples with NMO-IgG status predetermined at the Mayo Clinic. The anti-AQP4 antibody positivity rate was significantly higher in OSMS patients (13/48, 27.1%) than those with CMS (3/54, 5.6%), other neurological diseases (0/52) or healthy controls (0/35). None of the 11 patients tested with a brainstem-spinal form of MS were positive. Among OSMS patients, the antibody positivity rate was highest in OSMS patients with longitudinally extensive spinal cord lesions (LESCLs) extending over three vertebral segments and brain lesions that fulfilled the Barkhof criteria (5/9, 55.6%). Multiple logistic analyses revealed that emergence of the anti-AQP4 antibody was positively associated only with a higher relapse rate, but not with optic-spinal presentation or LESCLs. Compared with anti-AQP4 antibody-negative CMS patients, anti-AQP4 antibody-positive MS patients showed significantly higher frequencies of severe optic neuritis, acute transverse myelitis and LESCLs while most conditions were also common to anti-AQP4 antibody-negative OSMS patients. The LESCLs in anti-AQP4 antibody-positive patients were located at the upper-to-middle thoracic cord, while those in anti-AQP4 antibody-negative OSMS patients appeared throughout the cervical-to-thoracic cord. On axial planes, the former most frequently showed central grey matter involvement, while holocord involvement was predominant in the latter. In contrast, LESCLs in anti-AQP4 antibody-negative CMS patients preferentially involved the mid-cervical cord presenting a peripheral white matter-predominant pattern, as seen in the short lesions. Anti-AQP4 antibody-positive MS patients fulfilling definite NMO criteria showed female preponderance, higher relapse rate, greater frequency of brain lesions and less frequent responses to interferon beta-1b than anti-AQP4 antibody-negative OSMS patients with LESCLs. These findings suggested that LESCLs are distinct in anti-AQP4 antibody positivity and clinical phenotypes. There were cases of anti-AQP4 antibody-positive MS/NMO distinct from CMS, and anti-AQP4 antibody-negative OSMS with LESCLs in Japanese. This indicated that the mechanisms producing LESCLs are also heterogeneous in cases with optic-spinal presentation, namely AQP4 autoimmunity-related and -unrelated.

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

“…In a recent study 23 , multiple logistic analyses revealed that emergence of the anti-NMO-IgG antibody was positively associated with a higher relapse rate. Thus, this method can be a useful and reliable tool in NMO diagnosis and management in Brazilian patients, in spite of ethnical differences and genetic peculiarities of our population.…”

Clinical and laboratory characteristics of atopic myelitis: Korean experience

“…Cord swelling with focal enhancement was not frequent in non-AM patients. LESCL with selective gray matter on axial images, as is frequent in NMO or opticospinal multiple sclerosis (OSMS) [18,19], were observed in 9 of 15 patients, three of them developed recurrent myelitis. Eccentric large lesions were absent in this group.…”

Neuromielitis Óptica. Patología, diagnóstico y tratamiento en el siglo XXI

“…Este diagnóstico se establece cuando se cumplen los criterios diagnósticos de NMO establecidos en 1999 y actualizados en 2006. Para ello se debe considerar lo siguiente durante el proceso de evaluación (3,60,61):…”

“…estos habitualmente se hallan presentes en títulos bajos. aproximadamente el 50% de los pacientes los presentan de manera ya sea clínica o subclínica; sin embargo, el más importante de los anticuerpos séricos que se buscará es sin duda la presencia de igG-NMO que acercará al diagnóstico clínico del proceso (33,61,62).…”