中国人视神经脊髓炎疾病谱NMO-IgG/anti-AQP4抗体检测方法学的比较

Comparison Study on Antiacquaporin 4 Antibodies Detection by Different Techniques in Chinese Neuromyelitis Optica Spectrum

【目的】建立NMO-IgG/anti-AQP4抗体检测的间接免疫荧光法(IIF),细胞分析法(CBA)和荧光免疫沉淀法(FIPA)法;研究并比较不同的检测方法对中国人群NMO疾病谱的检测效率。【方法】建立3种检测NMO-IgG/anti-AQP4抗体的方法,包括IIF、CBA和FIPA。应用盲法检测病人血清106例,其中视神经脊髓炎(NMO)组24例,纵形扩展性脊髓炎(LETM)组22例,多发性硬化(MS)组30例,健康对照(HC)组30例;对其检测的阳性率进行分析。【结果】通过3种方法检测,发现NMO组NMO-IgG/anti-AQP4抗体阳性率分别为IIF(62.5%,15/24),CBA(91.7%,22/24)及FIPA(75.0%,18/22),LETM组为IIF(59.1%,13/22),CBA(86.4%,19/22)及FIPA(72.3%,16/22),MS组IIF、CBA及FIPA均为(3.3%,1/30)。正常对照组未见该抗体阳性表达。NMO组及LETM组血清NMO-IgG/anti-AQP4抗体阳性率明显高于MS和健康对照组。【结论】在中国人群NMO疾病谱患者中,IIF、CBA和FIPA的检测效率基本和美欧报道一致。IIF是该抗体检测的基础方法;CBA法看起来最为敏感;FIPA检测可以量化该抗体,可用于临床高通量大样品筛查。

【Objective】 To compare the performance of different assays （indirect immunofluorescence,cell-based assay,fluoroimmunoprecipitation assay） to detect anti-AQP4 antibodies in Chinese patients with neuromyelitis optica spectrum disorders. 【Methods】 Three assays have been set to detect anti-AQP4 antibodies,including Indirect immunofluorescence （IIF） assay with a composite substrate of mouse tissues,AQP4-transfected cell-based assay （CBA）,and a fluoroimmunoprecipitation assay （FIPA）. These assays were used in parallel to test seropositivity of masked serum samples from patients with neuromyelitis optica （NMO,24）,longitudinally extensive transverse myelitis （LETM,22）,multiple sclerosis （MS,30） and healthy controls （HC,30）. 【Results】 NMO-IgG,based on the conventional NMO-IgG assay by IIF,was detected in 15 of 24 （62.5%） in NMO. Antibodies against aquaporin-4 （AQP4-Ab） were found in 22 of 24 NMO patients （91.7%） by using CBA,in 18 of 22 （75.0%） by using FIPA. Seroprevalence in LETM patients were 13 / 22 （59.1% ） by IIF,19 / 22 （86.4% ） by CBA,16 / 22 （72.3% ） by FIPA separately. MS patients were 1 / 30（3.3%）by three methods,while any of HC patient was positive. 【Conclusions】 The frequency of NMO-IgG / anti-AQP4 antibodies detected by IIF,CBA and FIPA among Chinese patients with NMO spectrum disorders had similar performance with western published literature. IIF assay for NMO-IgG allows the detection of antibodies in routine screening ,but the CBA for AQP4 antibodies seems the most sensitive,and FIPA is suitable for high-throughput test for identifying positive sera and for serial estimations of antibody levels.