Establishment of a New Sensitive Assay for Anti-Human Aquaporin-4 Antibody in Neuromyelitis Optica
Establishment of a New Sensitive Assay for Anti-Human Aquaporin-4 Antibody in Neuromyelitis Optica
复制标题
DOI：
10.1620/tjem.210.307
复制
发表时间：
2006-12-01
影响因子：
2.2
通讯作者：
Itoyama, Yasuto
中科院分区：
文献类型：
--
作者：
Takahashi, Toshiyuki;Fujihara, Kazuo;Itoyama, Yasuto
视神经脊髓炎(NMO)是一种以严重的视神经炎和横贯性脊髓炎为特征的破坏性神经系统疾病。最近，用间接免疫荧光法发现了其疾病特异性自身抗体NMO-Ig G。然而，免疫荧光检测的底物不是人而是小鼠脑组织，这可能会影响抗体的敏感性和特异性。NMO-Ig G的靶抗原是水通道蛋白4(Aquaporin-4，AQP4)，主要在脑和脊髓中表达。在本研究中，我们建立了稳定表达人AQP4的人细胞系，并利用这些细胞用免疫荧光法检测和滴定存在于NMO患者血清中的抗AQP4抗体。并与原NMO-Ig G检测结果进行比较。我们检测了10名NMO患者、10名多发性硬化症患者和5名其他神经系统疾病患者的血清。在NMO患者中，有6例为NMO-IgG阳性。然而，使用新的抗AQP4抗体检测，我们发现8例NMO患者，其中6例NMO-Ig G阳性，抗AQP4抗体阳性。用这8例NMO患者的每种血清处理的AQP4表达细胞的染色模式与商用的抗AQP4抗体的染色模式一致。抗体效价(阳性染色的最大血清稀释度)为64倍至16,384倍。血清稀释滴度在盲法研究中是可重复性的。相比之下，患有MS或其他神经系统疾病的患者抗AQP4抗体呈阴性。因此，新开发的抗AQP4抗体检测方法对NMO的敏感性似乎比原来的NMO-IgG检测方法更高，有望用于NMO的诊断。
Neuromyelitis optica (NMO) is a devastating neurologic disease characterized by severe optic neuritis and transverse myelitis. Recently, its disease-specific serum autoantibody, NMO-IgG, was discovered with indirect immunofluorescence. However, the substrates of the immunofluorescence assay were not human but mouse brain tissues, which could influence the sensitivity and specificity of the antibody. The target antigen of NMO-IgG was recently identified as aquaporin-4 (AQP4) water channel protein, which is mainly expressed in brain and spinal cord. In the present study, we have established human cell lines that stably express human AQP4 and used these cells to detect and titrate anti-AQP4 antibody present in the sera of patients with NMO by immunofluorescence assay. The results were compared with those of the original NMO-IgG assay. We tested the sera from 10 patients with NMO, 10 with MS and five with other neurological disorders. Among the patients with NMO, six were NMO-IgG-positive. However, using the new anti-AQP4 antibody assay, we showed that eight patients with NMO including the six NMO-IgG-positives were positive for anti-AQP4 antibody. The staining pattern of AQP4-expressing cells treated with each serum of these eight NMO patients corresponded to that with a commercially available anti-AQP4 antibody. The antibody titer (maximum serum dilution for positive staining) ranged from 64x to 16,384x. The serum dilution titers were reproducible in blinded studies. In contrast, the patients with MS or other neurological disorders showed negative for anti-AQP4 antibody. Thus, the newly developed anti-AQP4 antibody assay appears to have a higher sensitivity for NMO than the original NMO-IgG assay and is expected to be useful for the diagnosis of NMO.