The role of anti-aquaporin 4 antibody in the conversion of acute brainstem syndrome to neuromyelitis optica.

Chen Cheng,Yongqiang Dai,Xueqiang Hu,Zhuang Kang,Xiaodong Lu,Fu Gu,Ying Jiang,Zhengqi Lu

doi:10.1186/s12883-016-0721-1

Abstract

BackgroundAcute brainstem syndrome (ABS) may herald multiple sclerosis (MS), neuromyelitis optica (NMO), or occur as an isolated syndrome. The aquaporin 4 (AQP4)-specific serum autoantibody, NMO-IgG, is a biomarker for NMO. However, the role of anti-AQP4 antibody in the conversion of ABS to NMO is unclear.MethodsThirty-one patients with first-event ABS were divided into two groups according to the presence of anti-AQP4 antibodies, their clinical features and outcomes were retrospectively analyzed.ResultsFourteen of 31 patients (45.16 %) were seropositive for NMO-IgG. The 71.43 % of anti-AQP4 (+) ABS patients converted to NMO, while only 11.76 % of anti-AQP4 (-) ABS patients progressed to NMO. Anti-AQP4 (+) ABS patients demonstrated a higher IgG index (0.68 ± 0.43 vs 0.42 ± 0.13, p < 0.01) and Kurtzke Expanded Disability Status Scale (4.64 ± 0.93 vs 2.56 ± 0.81, p < 0.01) than anti-AQP4 (-) ABS patients. Area postrema clinical brainstem symptoms occurred more frequently in anti-AQP4 (+) ABS patients than those in anti-AQP4 (-) ABS patients (71.43 % vs 17.65 %, p = 0.004). In examination of magnetic resonance imaging (MRI), the 78.57 % of anti-AQP4 (+) ABS patients had medulla-predominant involvements in the sagittal view and dorsal-predominant involvements in the axial view.ConclusionsABS represents an inaugural or limited form of NMO in a high proportion of anti-AQP4 (+) patients.

Highlights

Acute brainstem syndrome (ABS) may herald multiple sclerosis (MS), neuromyelitis optica (NMO), or occur as an isolated syndrome
All the patients involved in this study fulfilled the following inclusive criteria: 1) test for NMO-IgG; 2) single clinical episode of ABS associated with relevant brainstem magnetic resonance imaging (MRI) lesions 3) no other neurologic signs or symptoms which suggested the diagnosis of MS or NMO before NMO-IgG testing
A total of 31 patients who were enrolled in this study satisfied the diagnostic criteria: 14 anti-aquaporin 4 (AQP4) (+) patients with ABS and 17 anti-AQP4 (-) patients with ABS

Summary

Introduction

Acute brainstem syndrome (ABS) may herald multiple sclerosis (MS), neuromyelitis optica (NMO), or occur as an isolated syndrome. The role of anti-AQP4 antibody in the conversion of ABS to NMO is unclear. Acute brainstem syndrome (ABS) is an acute inflammatory demyelinating syndrome of the CNS that may occur in isolation or herald multiple sclerosis (MS), neuromyelitis optica (NMO), or recurrences of brainstem syndrome without other CNS manifestation (idiopathic recurrent brainstem encephalitis [RBE]) [1]. The aquaporin 4 (AQP4)-specific serum autoantibody, NMOIgG, is recognized as a specific biomarker for NMO [3]. ABS is recognized more frequently in patients with NMO spectrum disorder (NMOSD), most brainstem symptoms exist even before the diagnosis of NMOSD [10,11,12, 17]. The predictive value of anti-AQP4 antibody for relapse or later development was tested after the first sign of ABS

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