BACKGROUND Anti-neuronal autoantibodies have been reported as the cause of several neurologic disorders other than encephalitis. Unfortunately, data are mostly based on serum analysis. Predictions about pathogenicity are thus limited. To determine the presence of so far unidentified autoantibody-derived neuroreactivity we analyzed cerebrospinal fluid (CSF) of children with neurological disorders other than encephalitis. PATIENTS AND METHODS We did a retrospective analysis of CSF from 254 children with various neurologic diseases other than encephalitis and searched for reactivity against neuronal surface antigens by immunofluorescence on unfixed murine brain sections (tissue-based assay, TBA) and by commercial cell-based assays (CBA). A semi-quantitative fluorescence score classified our results and we described the clinical course of all positive patients with strong neuroreactivity. RESULTS Strong anti-neuronal IgG immunoreactivity of unknown antigen specificity was detected in CSF samples of 10 pediatric patients (4%, n = 10/254) with unsolved neurological disorders. CSF inflammatory markers were elevated. Most patients did not or only partly recover. Five screening-positive patients presented with a combination of headache and visual impairment due to optic nerve atrophy. Our data suggest to consider inflammatory, autoantibody-related etiologies, especially in cases without definite diagnoses. CONCLUSIONS We present an overview of CSF neuroreactivity in children with neurological disorders other than encephalitis, indicating the presence of unidentified anti-neuronal autoantibodies. As TBA enables screening for unknown autoantibodies, we suggest this method as a second step if commercial CBAs do not yield a result. Further studies are necessary to characterize such antibodies, evaluate pathogenicity, and answer the question whether positive CSF neuroreactivity should prompt an immunotherapeutic approach.

中文翻译：

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患有脑炎以外的神经系统疾病的儿童中存在抗神经元抗体

背景 抗神经元自身抗体已被报道为除脑炎之外的几种神经系统疾病的原因。不幸的是，数据主要基于血清分析。因此，关于致病性的预测是有限的。为了确定迄今为止未鉴定的自身抗体衍生神经反应性的存在，我们分析了患有除脑炎以外的神经系统疾病的儿童的脑脊液 (CSF)。患者和方法 我们对 254 名患有除脑炎以外的各种神经系统疾病的儿童的脑脊液进行了回顾性分析，并通过未固定鼠脑切片的免疫荧光（基于组织的测定，TBA）和基于商业细胞的测定来寻找对神经元表面抗原的反应性(CBA)。半定量荧光评分对我们的结果进行分类，我们描述了所有具有强神经反应性的阳性患者的临床过程。结果 在 10 名患有未解决的神经系统疾病的儿科患者 (4%, n = 10/254) 的 CSF 样本中检测到具有未知抗原特异性的强抗神经元 IgG 免疫反应性。脑脊液炎症标志物升高。大多数患者没有或仅部分康复。五名筛查阳性患者因视神经萎缩而出现头痛和视力障碍。我们的数据建议考虑炎症、自身抗体相关的病因，尤其是在没有明确诊断的情况下。结论 我们概述了患有除脑炎以外的神经系统疾病的儿童的脑脊液神经反应性，表明存在未鉴定的抗神经元自身抗体。由于 TBA 可以筛选未知的自身抗体，如果商业 CBA 没有产生结果，我们建议将此方法作为第二步。需要进一步研究来表征此类抗体，评估致病性，并回答阳性 CSF 神经反应性是否应促使免疫治疗方法的问题。