OBJECTIVE To explore levels of astrocytopathy in neuromyelitis optica spectrum disorder (NMOSD) by measuring levels of the astrocytic enzyme glutamine synthetase (GS) and glial fibrillary acidic protein (GFAP), an established astrocytic biomarker known to be associated with disease activity in multiple sclerosis. METHODS Cerebrospinal fluid concentrations of GS and GFAP were measured by ELISA in patients with NMOSD (n=39, 28 aquaporin-4 (AQP4)-Ab-seropositive, 3 double-Ab-seronegative, 4 myelin oligodendrocyte glycoprotein (MOG)-Ab-seropositive and 4 AQP4-Ab-seronegative with unknown MOG-Ab-serostatus), multiple sclerosis (MS) (n=69), optic neuritis (n=5) and non-neurological controls (n=37). RESULTS GFAP and GS concentrations differed significantly across groups (both p<0.001), showing a similar pattern of elevation in patients with AQP4-Ab-seropositive NMOSD. GS and GFAP were significantly correlated, particularly in patients with AQP4-Ab-seropositive NMOSD (rs=0.70, p<0.001). Interestingly, GFAP levels in some patients with double-Ab-seronegative NMOSD were markedly increased. CONCLUSIONS Our data indicate astrocytic injury occurs in some patients with double-Ab-seronegative NMOSD, which hints at the possible existence of yet undiscovered astrocytic autoimmune targets. We hypothesise that elevated GS and GFAP levels could identify those double-Ab-seronegative patients suitable to undergo in-depth autoimmune screening for astrocytic antibodies.

中文翻译：

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脑脊液中谷氨酰胺合成酶和GFAP的水平，以探讨血清阴性NMOSD中的星形细胞损伤。

目的通过测量星形细胞酶谷氨酰胺合成酶（GS）和神经胶质纤维酸性蛋白（GFAP）的水平，探讨视神经脊髓炎光谱疾病（NMOSD）的星形细胞病变水平。神经胶质纤维酸性蛋白（GFAP）是公认的与多发性硬化症疾病活动相关的星形细胞生物标志物。方法采用ELISA法检测NMOSD（n = 39，aquaporin-4（AQP4）-Ab-血清反应阳性，3 ab-Ab-sereggative阴性，NelD少突胶质细胞糖蛋白（MOG）-Ab-Ab-39，n = 39）的脑脊液中GS和GFAP的浓度血清阳性和4例AQP4-Ab阴性，而MOG-Ab血清状态未知），多发性硬化症（MS）（n = 69），视神经炎（n = 5）和非神经控制（n = 37）。结果各组之间的GFAP和GS浓度差异显着（均p <0.001），在AQP4-Ab血清阳性NMOSD患者中显示出相似的升高模式。GS和GFAP显着相关，特别是在AQP4-Ab血清反应阳性的NMOSD患者中（rs = 0.70，p <0.001）。有趣的是，某些双Ab血清阴性NMOSD患者的GFAP水平明显升高。结论我们的数据表明，某些双Ab血清阴性NMOSD患者发生星形胶质细胞损伤，这提示可能存在尚未发现的星形胶质细胞自身免疫靶标。我们假设升高的GS和GFAP水平可以识别出那些适合进行星形细胞抗体的深入自身免疫筛选的双Ab血清阴性患者。某些双Ab血清阴性NMOSD患者的GFAP水平显着升高。结论我们的数据表明，某些双抗体阴性NMOSD患者发生星形胶质细胞损伤，这提示可能存在尚未发现的星形胶质细胞自身免疫靶标。我们假设升高的GS和GFAP水平可以识别出那些适合进行星形细胞抗体的深入自身免疫筛查的双Ab血清阴性患者。某些双Ab血清阴性NMOSD患者的GFAP水平显着升高。结论我们的数据表明，某些双Ab血清阴性NMOSD患者发生星形胶质细胞损伤，这提示可能存在尚未发现的星形胶质细胞自身免疫靶标。我们假设升高的GS和GFAP水平可以识别出那些适合进行星形细胞抗体的深入自身免疫筛查的双Ab血清阴性患者。