[Detection of anti-aquaporin 4 antibody in neuromyelitis optical].

OBJECTIVE: To assess the sensitivity and specificity of anti-aquaporin 4 antibody in the diagnosis of neuromyelitis optical (NMO) and analyze the relationship between clinical features and different NMO-IgG status. METHODS: A total of 269 serum specimens were collected from the patients with NMO, high-risk for NMO, multiple sclerosis (MS) and miscellaneous diseases and analyzed with HEK-293T cells transfected by aquaporin 4 cDNA. The sensitivity and specificity of anti-aquaporin 4 antibody in the diagnosis of NMO were calculated, Spearman correlation coefficients were used to examine the relationship between clinical features and antibody titer. RESULTS: (1) The results of cell-based immunofluorescence assay showed 36 examples of 47 NMO patient serums (76.6%) were positive, 7/23 high-risk for NMO positive (30.4%), 3/85 multiple sclerosis (3.5%) positive, 1/48 miscellaneous neurological disorders (2.1%), 2/16 immune system diseases positive (12.5%) and negative in all 50 healthy serum specimens. Sensitivity and specificity were 76.6% and 97.0% for discriminating NMO from MS and other diseases. (2) Anti-AQP4 antibody titer had no obvious correlation to relapses, spinal lesion length and EDSS (P > 0.05). (3) Anti-AQP4 antibody titer became lower after a high dose of intravenous methylprednisolone (P < 0.05). CONCLUSION: Anti-AQP4 antibody in NMO has a high specificity and sensitivity so as to contribute to early diagnosis and optimized treatment of NMO. And its titer decreases after a high dose of intravenous methylprednisolone. But there is no correlation between its titer and length of spinal cord lesions, relapsing frequency or expanded disability status scale (EDSS) score.

[The clinical and magnetic resonance imaging studies of brain damages in neuromyelitis optica].

OBJECTIVE: To investigate the feature brain damage and clinical manifestations in neuromyelitis optica (NMO) patients; To investigate the relationship between serum NMO-IgG antibody and NMO brain damage. METHODS: Clinical data of 37 NMO patients and their head and spinal cord MRI by 1.5T superconducting MR scanner, were analyzed; serum NMO-IgG antibody were measured by immunofluorescence. RESULTS: 17 cases were found to have abnormal signals on MRI, which were mainly in the white matter, pons, medulla, ventricle, aqueduct, and around the corpus callosum; According to pathological changes, brain damage can be divided into scattered irregularity (13 cases), fusion (3 cases), multiple sclerosis-like (1 case), with scattered irregularity more common, 5 cases had clinical manifestations of brain damage: somnolence, vomiting, diplopia, visual rotation, 11 cases patients with brainstem damage show positive serum NMO-IgG antibodies. CONCLUSIONS: Brain damage can be seen in half of NMO patients, they often located in the high expression area of AQP4: brain white matter, periventricular, brainstem and so on. Clinical symptoms has nothing to do with the size of lesions but the location, they often occur when brainstem was involved. Serum NMO-IgG is helpful in differentiating NMO with brain damage and MS.

[Comparison of three anti-aquaporin 4 antibody detection methods in neuromyelitis optical].

OBJECTIVE: To evaluate three methods of detecting anti-aquaporin 4(AQP4) antibody in neuromyelitis optical(NMO), including indirect immunofluorescence assay organization (IIF), cell immunofluorescence method (CBA) and ELISA. METHODS: The patients were divided into NMO group (n = 29), multiple sclerosis (MS) group (n = 23), and healthy controls group (n = 50). IIF, CBA and ELISA were used in 3 groups to detect serum anti-AQP4 antibody. The sensitivity and specificity as well as the consistency of positive results were compared. RESULTS: In the aspect of the sensitivity of the three anti-AQP4 antibody to diagnosis NMO, CBA (72.4%) > IIF (62.1%) > ELISA (51.7%); in the aspect of specificity, CBA (100.0%) > ELISA (98.6%) > IIF (97.3%). Kappa testing and evaluation method showed that the three detection methods were all in good consistency, particular in CBA and ELISA (P < 0.01). CONCLUSIONS: CBA method showed a highest specificity and sensitivity in all these three anti-AQP4 antibody detection methods. CBA and ELISA are in better consistency of positive results.

[Neuromyelitis optica IgG and related clinical features of patients with neuromyelitis optica].

OBJECTIVE: To investigate the differential diagnostic value of NMO-IgG for neuromyelitis optica (NMO) versus multiple sclerosis (MS) and to analyze its possible clinical features related to NMO-IgG. METHODS: Forty-one NMO patients and 44 MS patients in acute phase and 40 healthy controls were investigated. Serum NMO-IgG was tested by indirect immunofluorescence assay. The disability severity in NMO and MS patients was assessed by Expanded Disability Status Scale (EDSS). Clinical features and MRI imaging profiles were analyzed between NMO-IgG positive patients and negative ones. RESULTS: 70.7% (29/41) NMO patients were NMO-IgG positive compared to 9.1% (4/44) MS patients and all healthy controls were NMO-IgG negative (P < 0.01). The sensitivity and specificity were 70.7% and 90.9% respectively when NMO-IgG was used to discriminate NMO from MS. NMO patients with positive NMO-IgG had significantly higher EDSS scores (P < 0.05). More NMO-IgG seropositive patients had longitudinally extensive cord lesions (≥ 3 segments) than the NMO-IgG seronegative patients (93.1% vs 66.7%). But the difference was insignificant. CONCLUSION: NMO-IgG is a specific biomarker of NMO. NMO-IgG can facilitate an early differentiation of NMO from MS. NMO-IgG seropositivity is related to graver symptoms and it may predict an aggravation.

[Construction and clinical application of lentivirus-AQP4 expressing vector].

OBJECTIVE: To construct the human aquaporin-4 (AQP4) expressing vector and detect anti-AQP4 antibody in serum of patients with neuromyelitis optica (NMO). METHODS: RNA was extracted from human glioblastoma and AQP4 cDNA obtained through RT-PCR.The fragment was cloned into the lentiviral expressing vector (iDUET101) and transformed into competent strain Hb101 for later amplification; plasmids were extracted from the amplified positive-bacteria-colony, sequenced and transfected into HEK-293T cells. Expression of AQP4 was identified by RT-PCR, Western blot and immunofluorescence assay. And anti-AQP4 antibody in human serum was tested. RESULTS: The sequence of target fragment matched with that of human AQP4 fragment sequences (NM_001650) completely. The constructed AQP4 fragment transfected in HEK-293T cell was tested by immunofluorescent examination and it exhibited obvious fluorescence located in cell membrane. Western blot test was positive. And the fragment was about 34 KD. Cellular immunofluorescence examination showed 11 examples of 12 NMO patient serums (91.7%) were positive, 4 in 34 multiple sclerosis (11.8%) positive and negative in all 50 serum samples of healthy controls. CONCLUSION: The HEK-293T cell transfected with lentivirus-AQP4 vector can express stably. And the expressed fragment may be applied in clinical examination.