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Background: The prevalence of antibodies against M-type anti-phospholipase A2 receptor (PLA2R) was reported to be ~ 70-80% in early studies on idiopathic membranous nephropathy (iMN) cohorts from Western countries, China, and Korea, and ~ 50% in recent studies on two Japanese iMN cohorts., Methods: We developed an in-house enzyme-linked immunosorbent assay (ELISA) for the detection of anti-PLA2R antibodies, and examined sera from 217 patients with iMN, 22 patients with secondary MN (sMN), and 50 healthy individuals. All patients and healthy individuals were Japanese. The relationships between levels of anti-PLA2R antibodies and clinical parameters were analyzed. Serum samples were also tested using a standardized commercial ELISA (Euroimmun, Germany)., Results: In our ELISA, OD values greater than the mean + 3 standard deviation of healthy subjects were considered to be positive for anti-PLA2R antibodies. Of the patients with iMN, 33.6% (73/217) were positive, but all sMN patients were negative. Our ELISA and the Euroimmun ELISA had a high concordance (93.5%). The proportion of patients with nephrotic syndrome was significantly higher in anti-PLA2R antibody-positive patients than in antibody-negative patients (65.8 vs. 37.5%, P < 0.001). Levels of anti-PLA2R antibodies were significantly correlated with levels of urinary protein and serum albumin (P = 0.004 and P < 0.001, respectively)., Conclusions: The prevalence of anti-PLA2R antibodies in our Japanese iMN cohort was lower than that in the previous studies from other countries and other Japanese institutes. The low prevalence of antibodies may be related with the characteristics of enrolled patients with mild proteinuria and undetectable antibody levels.

Objectives: We asked whether autoantibodies against neurofascin (NF)186 or NF155, both localized at the nodes of Ranvier, are present in serum of patients with inflammatory neuropathy, and whether NF-specific monoclonal antibodies are pathogenic in vivo., Methods: We cloned human NF155 and NF186, and developed an ELISA and cell-based assay to screen for antibodies to human NF in a total of 434 donors including 294 patients with Guillain-Barré syndrome variants acute inflammatory demyelinating polyneuropathy (AIDP), acute motor axonal neuropathy, and chronic inflammatory demyelinating polyneuropathy (CIDP). We characterized reactive samples by isotyping, tissue section staining, and epitope mapping. We also injected NF-specific monoclonal antibodies IV into rats with experimental autoimmune neuritis., Results: We detected autoantibodies to NF by ELISA in 4% of patients with AIDP and CIDP, but not in controls. Most positive samples contained immunoglobulin G (IgG)1, IgG3, or IgG4 antibodies directed to only one isoform of NF. Two patients with CIDP showed particularly high (1:10,000 dilution) NF155-specific reactivity in both assays and stained paranodes. Two other patients with CIDP who benefited from plasma exchange exhibited antibodies to NF155 by ELISA, and upon affinity purification, antibodies to both isoforms were observed by both assays. Anti-NF monoclonal antibodies enhanced and prolonged induced neuritis in rats., Conclusions: Autoantibodies to NF are detected in a very small proportion of patients with AIDP and patients with CIDP, but may nevertheless be pathogenic in these cases.

Neurofascin-186 (NF186), neuronal cell adhesion molecule (NrCAM), and gliomedin are adhesion molecules playing a central role in the formation of nodes of Ranvier. In Guillain-Barré syndrome (GBS), immune attack toward the nodes may participate in the disabilities. Autoantibodies to NF186 and gliomedin have been detected in a rat model of GBS. Here, we investigated the prevalence of antibodies against nodal adhesion molecules in patients with GBS or chronic inflammatory demyelinating polyneuropathy (CIDP). Sera from 100 GBS patients, 50 CIDP patients, 80 disease controls, and 50 healthy controls were tested for their ability to bind the nodes of Ranvier. To characterize the antigens, we performed cell binding assays against NF186, gliomedin, contactin, and NrCAM. We found that 43% of patients with GBS and 30% of patients with CIDP showed IgG fixation at nodes or paranodes. In eight patients with GBS or CIDP, we identified that IgG antibodies recognized the native extracellular domain of NF186, gliomedin, or contactin. Also, 29 patients showed IgM against nodal adhesion molecules. However, we did not detect IgM fixation at nodes or paranodes. Antibodies to gliomedin or NF186 were mostly detected in demyelinating and axonal GBS, respectively. The adsorption of the antibodies to their soluble antigens abolished IgG deposition at nodes and paranodes in nerves, indicating these were specific to NF186, gliomedin, and contactin. In conclusion, gliomedin, NF186, and contactin are novel target antigens in GBS. At nodes, additional epitopes are also the targets of IgG. These results suggest that antibody attack against nodal antigens participates in the etiology of GBS., (© 2012 Peripheral Nerve Society.)

Background: Clinical severity of Guillain-Barré syndrome (GBS) is highly variable, but the immunopathological reason is unknown., Objective: The study was designed to show which antibody parameters are associated with disease severity in GBS patients with serum anti-GM1 IgG antibodies., Methods: Thirty-four GBS patients with anti-GM(1) IgG antibodies were grouped into two categories according to disease severity at nadir: mild (grades 1-3 by Hughes functional scale, n=13) and severe (grades 4 and 5, n=21). Titre, affinity, fine specificity and cell binding of anti-GM(1) antibodies were obtained and compared between the two groups., Results: No differences in antibody titre (GM(1)-ELISA) or affinity were found between the two patient groups. In contrast, the severe group showed a significantly higher frequency (95%, vs 46% in the mild group, p=0.002) of specific (not cross-reacting with GD(1b)) anti-GM(1) antibodies. In addition, the severe group also exhibited a higher antibody binding titre to cellular GM(1)., Conclusions: Differences in fine specificity of antibodies are strong indications that different regions of the GM(1)-oligosaccharide are involved in antibody binding. High titres of specific anti-GM(1) antibody binding to cellular GM(1) can be explained by antigen exposure, that is, GM(1) exposes or forms mainly epitopes recognised by specific antibodies, and 'hides' those involved in binding of cross-reacting antibodies. Thus, the fine specificity of anti-GM(1) antibodies may influence disease severity by affecting antibody binding to cellular targets. Additionally, since antibody specificity studies are relatively easy to implement, fine specificity could be considered a useful predictor of disease severity.

Studies have demonstrated that B cells play important roles in systemic sclerosis (SSc), especially through the CD19/CD22 autoimmune loop. CD22 is a B cell-specific inhibitory receptor that dampens B cell antigen receptor (BCR) signalling via tyrosine phosphorylation-dependent mechanism. In this study, we examined the presence and functional property of circulating autoantibodies reacting with CD22 in systemic sclerosis. Serum samples from 10 tight skin (TSK/+) mice and 50 SSc patients were assessed for anti-CD22 autoantibodies by enzyme-linked immunosorbent assays using recombinant mouse or human CD22. The association between anti-CD22 antibodies and clinical features was also investigated in SSc patients. Furthermore, the influence of SSc serum including anti-CD22 autoantibodies for CD22 tyrosine phosphorylation was examined by Western blotting using phosphotyrosine-specific antibodies reacting with four major tyrosine motifs of CD22 cytoplasmic domain. Anti-CD22 autoantibodies were positive in 80% of TSK/+ mice and in 22% of SSc patients. Patients positive for anti-CD22 antibodies showed significantly higher modified Rodnan skin thickness score compared with patients negative for anti-CD22 antibodies. Furthermore, anti-CD22 antibodies from patients' sera were capable of reducing phosphorylation of all four CD22 tyrosine motifs, while sera negative for anti-CD22 antibodies did not affect CD22 phosphorylation. Thus, a subset of SSc patients possessed autoantibodies reacting with a major inhibitory B cell response regulator, CD22. Because these antibodies can interfere CD22-mediated suppression onto B cell activation in vitro, SSc B cells produce functional autoantibodies that can enhance their own activation. This unique regulation may contribute to the autoimmune aspect of SSc.

Ganglioside mimicry of Campylobacter jejuni lipo-oligosaccharide (LOS) can induce the production of IgG anti-ganglioside antibodies, but the generation mechanism has yet to be clarified. B-cell activating factor belonging to the TNF family (BAFF) helped murine B cells produce anti-ganglioside antibodies against C. jejuni LOS. In splenocyte culture, however, anti-ganglioside antibodies were produced in the presence of a soluble transmembrane activator and calcium-modulating and cyclophilin ligand interactor immunoadhesin (TACI-Ig), a receptor for BAFF. TACI-Ig adenoviral vectors failed to decrease production of anti-ganglioside antibodies in mice sensitized with C. jejuni LOS and did not alter IgG subclasses, evidence that BAFF aids but is not essential for the generation of IgG anti-ganglioside antibodies in response to C. jejuni LOS., (Copyright 2009 Elsevier B.V. All rights reserved.)

We report the case of a 50-year-old man with paraneoplastic cerebellar degeneration (PCD) and Lambert-Eaton myasthenic syndrome (LEMS) associated with primary double lung cancer. He developed acute progressive double vision, slurred speech, and gait disturbance. Neurological examination revealed diplopia, mild ptosis, bilateral horizontal gaze-evoked nystagmus, and cerebellar limb and truncal ataxia. The diffusion image of brain magnetic resonance imaging (MRI) revealed no abnormal findings in the cerebellum. On the basis of the diagnosis of acute cerebelitis, he was given methylprednisolone pulse therapy followed by oral prednisolone, which gradually improved his neurological signs and symptoms. The analysis of the possible etiology suggested that the PCD was induced by lung cancer, which led to ataxia. A chest computed tomography scan revealed mass lesions of irregular shape and unclear margins in the upper lobe of the right lung and a small nodule tumor in the upper lobe of the left lung. We performed transbronchial needle aspiration and detected the bronchioloalveolar carcinoma of the right lung. An electromyogram showed waxing phenomenon in the ulnar nerve at high-frequency (50Hz) stimulation. The serum levels of anti-P/Q-type voltage-gated calcium channel (VGCC) antibody were elavated in the patient. These findings confirmed that the pathogenesis of the condition of this patient to be associated with LEMS. His cerebellar symptoms were considered to be caused by the PCD, and the diplopia, ptosis, and hyporeflexia were attributed to LEMS. We performed upper left lobectomy with mediastinal lymphnode dissection via video-assisted thoracoscopic surgery. A histological study detected small cell carcinoma. A diagnosis of double primary lung cancer was made. Physicians need to be aware that patients may develop PCD and LEMS associated with anti-VGCC antibody caused by small cell lung cancer, and a mass survey should be conducted and careful examinations performed.

The authors reported the neurological disease spectrum associated with autoantibodies against minor gangliosides GM1b and GalNAc-GD1a. IgG and IgM antibody reactivity against gangliosides GM1, GM2, GM1b, GD1a, GalNAc-GD1a and GQ1b was investigated in sera from 7000 consecutive patients who had various neurological conditions. The clinical diagnoses for 456 anti-GM1b-positive patients were Guillain-Barré syndrome (GBS, 71%), atypical GBS with preserved deep tendon reflexes (12%), Fisher syndrome (10%), Bickerstaff's brainstem encephalitis (2%), ataxic GBS (2%) and acute ophthalmoparesis (1%). For 193 anti-GalNAc-GD1a-positive patients, the diagnoses were GBS (70%), atypical GBS (16%), Fisher syndrome (10%) and Bickerstaff's brainstem encephalitis (3%). Of the patients with GBS or atypical GBS, 28% of 381 anti-GM1b-positive and 31% of 166 anti-GalNAc-GD1a-positive patients had neither anti-GM1 nor anti-GD1a antibodies. Of those patients with Fisher syndrome, Bickerstaff's brainstem encephalitis, ataxic GBS or acute ophthalmoparesis, 33% of 67 anti-GM1b-positive, and 52% of 25 anti-GalNAc-GD1a-positive patients had no anti-GQ1b antibodies. Autoantibodies against GM1b and GalNAc-GD1a are associated with GBS, Fisher syndrome and related conditions. These antibodies should provide useful serological markers for identifying patients who have atypical GBS with preserved deep tendon reflexes, ataxic GBS, Bickerstaff's brainstem encephalitis or acute ophthalmoparesis, especially for those who have no antibodies to GM1, GD1a or GQ1b. A method to prepare GM1b was developed.

The authors reviewed clinical profiles and laboratory findings for 100 cases of abducens nerve paresis without impairment of the other cranial nerves, limb weakness, and ataxia throughout the clinical course. Review of the medical records of 9300 patients referred to our neuoroimmunological laboratory for serum anti-ganglioside antibody testing. Information was obtained from each primary physician on symptoms of preceding infection; initial symptoms; neurological signs during the illness; the clinical course; treatment provided; and outcome. Isolated abducens nerve paresis was present in 100 patients and bilateral paresis in 29. Tentative diagnoses made by the primary physicians on request of anti-ganglioside antibody testing were abducens nerve palsy (n = 68), Fisher syndrome (n = 14), acute ophthalmoparesis without ataxia (n = 14). Symptoms of infection anteceded in 63. Tendon reflexes were absent or decreased in 27. Distal paresthesias were experienced by seven. Serum anti-GQ1b antibody was positive in 25. These findings suggest that some cases of isolated abducens nerve palsy can be categorized as a regional variant of Guillain-Barré syndrome or mild form of Fisher syndrome.

Anti-GD1a ganglioside antibodies (Abs) are the serological hallmark of the acute motor axonal form of the post-infectious paralysis, Guillain-Barre syndrome. Development of a disease model in mice has been impeded by the weak immunogenicity of gangliosides and the apparent resistance of GD1a-containing neural membranes to anti-GD1a antibody-mediated injury. Here we used mice with altered ganglioside biosynthesis to generate such a model at motor nerve terminals. First, we bypassed immunological tolerance by immunizing GD1a-deficient, beta-1,4-N-acetylgalactosaminyl transferase knock-out mice with GD1a ganglioside-mimicking antigens from Campylobacter jejuni and generated high-titer anti-GD1a antisera and complement fixing monoclonal Abs (mAbs). Next, we exposed ex vivo nerve-muscle preparations from GD1a-overexpressing, GD3 synthase knock-out mice to the anti-GD1a mAbs in the presence of a source of complement and investigated morphological and electrophysiological damage. Dense antibody and complement deposits were observed only over presynaptic motor axons, accompanied by severe ultrastructural damage and electrophysiological blockade of motor nerve terminal function. Perisynaptic Schwann cells and postsynaptic membranes were unaffected. In contrast, normal mice were not only unresponsive to immunization with GD1a but also resistant to neural injury during anti-GD1a Ab exposure, demonstrating the central role of membrane antigen density in modulating both immune tolerance to GD1a and axonal susceptibility to anti-GD1a Abmediated injury. Identical paralyzing effects were observed when testing mouse and human anti-GD1a-positive sera. These data indicate that anti-GD1a Abs arise via molecular mimicry and are likely to be clinically relevant in injuring peripheral nerve axonal membranes containing sufficiently high levels of GD1a.

To clarify the clinical features of patients with anti-GalNAc-GD1a antibody, we retrospectively investigated which conditions were associated with anti-GalNAc-GD1a antibody in a large number of patients. Sixty-four out of 1,713 patients had anti-GalNAc-GD1a IgG antibody. Fifty-seven (89%) were diagnosed with Guillain-Barré syndrome (GBS) or atypical GBS with preserved deep tendon reflexes. These patients were characterized by young man, antecedent diarrhea, distal-dominant limb weakness, and absence of cranial nerve impairment and sensory disturbance. Some of sera from patients had anti-GM1, anti-GM1b, and anti-GD1a IgG antibodies associated with axonal GBS. Our study suggests that the anti-GalNAc-GD1a antibody testing is useful for supporting the diagnosis of GBS. In addition, fine specificity of the antibody also was clarified.

Patients with the pharyngeal-cervical-brachial variant (PCB) of Guillain-Barré syndrome (GBS) have anti-GT1a IgG with or without GQ1b reactivity, whereas those with Fisher syndrome (FS) or Bickerstaff's brainstem encephalitis (BBE) have anti-GQ1b IgG antibodies which cross-react with GT1a. The nosological relationship between these conditions has yet to be established. To investigate the relationships between each manifestation and between clinical features and the coexistence of anti-GQ1b IgG, we reviewed neurological signs present during illnesses of 140 patients who had anti-GT1a IgG. Based on our criteria, FS was diagnosed for 64 (46%) patients, GBS for 22 (16%), BBE for 14 (10%), and PCB for 6 (4%). Overlapping conditions were diagnosed for some patients: FS and GBS (5%), PCB and FS (5%), BBE and GBS (4%), and PCB and BBE (1%). Patients who initially had bulbar palsy developed not only PCB but FS or BBE. The population of anti-GT1a-positive patients frequently had ophthalmoplegia, ataxia, and areflexia, whereas the subpopulation who had anti-GT1a IgG without GQ1b reactivity frequently had preceding diarrhea as well as oropharyngeal, neck, and limb weakness. Patients with anti-GT1a IgG presented a variety of clinical conditions, indicative of a continuous clinical spectrum. A major part of this clinical variation was due to the coexistence of anti-GQ1b IgG. The presence of a common autoantibody (anti-GT1a IgG) and overlapping illnesses suggests that PCB is closely related not only to GBS but to FS and BBE as well.

This is the first report of a case of Bickerstaff's brainstem encephalitis (BBE) associated with IgM antibodies to GM1b and GalNAc-GD1a. Subsequent to Campylobacter jejuni enteritis, the patient rapidly developed consciousness disturbance and hyperreflexia in addition to external ophthalmoplegia and cerebellar-like ataxia. EEG showed transient 7 Hz monorhythmic theta activities, predominantly in the front-central area. He received high doses of immunoglobulin intravenously and had completely recovered 3 months later. High anti-GM1b and anti-GalNAc-GD1a IgM antibody titers present during the acute phase decreased with his clinical improvement. An absorption study showed the anti-GM1b and anti-GalNAc-GD1a IgM antibodies to be cross-reactive. Anti-GM1b and anti-GalNAc-GD1a antibodies have been detected in some patients who developed Guillain-Barré syndrome after C. jejuni enteritis, whereas the anti-GQ1b IgG antibody is associated with BBE. Infection by C. jejuni bearing a GM1b-like or GalNAc-GD1a-like lipooligosaccharide may trigger the production of anti-GalNAc-GD1a and anti-GM1b IgM antibodies. It is not clear why our patient developed BBE rather than Guillain-Barré syndrome. These antibodies may, however, prove useful serological markers for identifying BBE patients who do not have the anti-GQ1b IgG antibody.

To clarify the clinical features of patients with anti-GM1b antibody, we retrospectively investigated which conditions were associated with anti-GM1b antibody in a large number of patients. Two hundred out of 1,713 patients had anti-GM1b antibody. One hundred and sixty-six (83%) were diagnosed with Guillain-Barré syndrome (GBS) or atypical GBS with preserved deep tendon reflexes. Our study suggests that the anti-GM1b antibody testing is useful for supporting the diagnosis of GBS. In addition, anti-GM1b antibody was detected in 18 patients with Fisher syndrome and the related conditions associated with anti-GQ1b IgG antibody, and 3 patients with ataxic GBS associated with anti-GD1b IgG antibody.

Objective: To examine the clinical features of acute ophthalmoparesis (AO) (without ataxia) associated with anti-GQ1b immunoglobulin G (IgG) antibody., Design: Retrospective observational case series., Participants: Twenty-one subjects with AO (without ataxia) who had anti-GQ1b IgG., Methods: Clinical features of 21 subjects with AO were analyzed., Results: Seventeen had symptoms of antecedent infection. Gaze limitation was bilateral in 16 subjects and unilateral in five, indicative that laterality does not always negate AO. Nine subjects showed abducens paresis, and two limitation of abduction and adduction. Eight, who initially had bilateral abducens palsy, subsequently had impairment of adduction and vertical movement. These showed that bilateral abducens palsy followed by oculomotor nerve involvement is characteristic of AO. Muscle stretch reflexes were normal in nine subjects, hypoactive in eight, absent in three, and brisk in one. Distal paresthesias were present in seven subjects. Acellular cerebrospinal fluid (CSF) associated with raised protein concentration was detected in three., Conclusions: Antecedent infectious symptoms, characteristic limitation of ocular movement, areflexia, distal paresthesias, and CSF albuminocytologic dissociation are useful markers for diagnosing AO as well as anti-GQ1b IgG. AO can be considered a mild form of Miller Fisher syndrome or a regional variant of Guillain-Barré syndrome.

Immunoadsorption therapy (IAT) using the tryptophan column (TR:TR-350, Asahi Medical Co., Tokyo, Japan) is used for patients with Guillain-Barré syndrome or Fisher's syndrome. Recently, a modified tryptophan column (modified TR:TR-350S, Asahi) was developed to reduce adsorption of fibrinogens. However, it is not clear whether the new column can effectively adsorb the antiganglioside antibodies. We treated 2 patients with Guillain-Barré syndrome, 1 patient with Fisher's syndrome, and 1 patient with Bickerstaff's brainstem encephalitis by IAT using the TR and the modified TR. Samples were taken from the inlet and outlet of the affinity column. We compared the adsorption ability of antiganglioside antibodies between the TR and modified TR. The modified TR adsorbed antiganglioside antibodies less effectively than the TR. No significant bleeding was observed in the patients during each session. Furthermore, results of the clinical study were confirmed by batchwise adsorption test. We propose that the modified TR should not be used for treating patients with Guillain-Barré syndrome and related disorders.