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Agrin is essential for neuromuscular junction (NMJ) formation and maintenance. The C-terminal agrin fragment (CAF), generated by neurotrypsin-mediated cleavage of agrin, has been gaining attention as a potential biomarker for sarcopenia. We investigated serum CAF levels in myasthenia gravis (MG), a NMJ disorder. Compared to healthy controls, serum CAF levels were significantly elevated in acetylcholine receptor antibody-positive MG (AChR-MG) patients, but not in muscle-specific kinase antibody-positive MG patients. In AChR-MG, baseline and post-treatment CAF levels inversely correlated with post-treatment MG activities of daily living scores, suggesting that elevated CAF levels may reflect protective mechanisms against AChR-MG pathogenesis, such as improved NMJ regeneration., Competing Interests: Declaration of competing interest A. Uzawa received honoraria from UCB, Alexion Pharmaceuticals, and Argenx., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

This study included 51 patients with muscle-specific kinase antibody-positive myasthenia gravis (MuSK-MG) from a Japanese multicenter survey to examine clinical features and outcomes. Median onset age was 37 years and female predominance was observed. All patients developed generalized symptoms and almost all (50/51) patients had bulbar symptoms. About half of the patients met the criteria for refractory MG. The refractory group had a lower age of onset, higher severity scores, and higher maximum daily doses of oral prednisolone compared to the nonrefractory group. The outcomes for MuSK-MG patients in Japan are not favorable, indicating the need for more aggressive treatment., Competing Interests: Declaration of Competing Interest AU received honoraria from Alexion Pharmaceuticals and Argenx. SK received Health and Labour Sciences Research Grant on Intractable Diseases (Neuroimmunological Diseases) from the Ministry of Health, Labour and Welfare of Japan (23FC1009) and honoraria from CSL Behring. TK reported honoraria for lectures from Argenx, Alexon Pharmaceuticals, and UCB Pharma. SS received speakers' fees from Alexion Pharmaceuticals, the Japan Blood Products Organization, Asahi Kasei Medical, and Argenx and participated in advisory board meetings of Alexion Pharmaceuticals and Argenx. MPT reported unrestricted research grants from Japan Blood Products Organization, Astellas Pharma, Mitsubishi Tanabe Pharma, and Pfizer outside the submitted work, served as a paid Consultant for Alexion, Argenx, Sanofi, and UCB Pharma, and received an honorarium for lectures from Argenx, Alexion Pharmaceuticals, and UCB Pharma. MM received speaker honoraria from Argenx, Asahi Kasei Medical, and Alexion Pharmaceutical and participated in advisory board meetings of Alexion Pharmaceutical. YN received speaker honoraria from Argenx, Alexion Pharmaceuticals, Japan Blood Products Organization, and UCB Pharma. KU served as a paid Consultant for UCB Pharma, Janssen Pharma, Horizon Therapeutics (Viela Bio), Chugai Pharma, Hanall BioPharma, Merck, and Mitsubishi Tanabe Pharma and received speaker honoraria from Argenx, Alexion Pharmaceuticals, UCB Pharma, and the Japan Blood Products Organization. Other authors declare no financial or other conflicts of interest., (Copyright © 2023 Elsevier B.V. All rights reserved.)

This study measured the serum levels of of 15 cytokines in 15 patients with anti-muscle-specific kinase antibody-positive MG (MuSK-MG) using a multiplex suspension array system. Fifteen patients with non-inflammatory neurological diseases served as controls. Compared with controls, patients with MuSK-MG showed higher levels of Th1- (IFN-γ), Th2- (IL-25, IL-31, and IL-33), Th17- (IL-22), Treg-related cytokines (IL-10), and soluble CD40 ligand (sCD40L). Higher serum Th2-related cytokines (IL-25 and IL-31) levels were correlated with less MG Foundation of America (MGFA) class. These suggest that Th2-related cytokines have protective effects, whereas sCD40L and others may facilitate the disease., Competing Interests: Declaration of Competing Interest A. Uzawa has received honoraria from Alexion Pharmaceuticals and Argenx., (Copyright © 2023 Elsevier B.V. All rights reserved.)

The purpose of this study was to evaluate the safety and efficacy of BL 23 (Shenshu) acupuncture on serum cytokine levels. Sixteen healthy adults were randomized into the BL 23 acupuncture group or pseudo-acupuncture group and changes of serum cytokines were analyzed. The changes in IL-13, TNF-α, and GM-CSF levels were different between the BL 23 acupuncture group and pseudo-acupuncture group (P < 0.05). No adverse events associated with acupuncture were observed. In conclusion, BL 23 acupuncture can suppress immune responses via decreases in TNF-α and suppression of increases in IL-13 and GM-CSF. This study elucidated some of the mechanisms of the acupuncture effect., Competing Interests: Declaration of Competing Interest There are no conflicts of interest to disclose in this study., (Copyright © 2023 Elsevier B.V. All rights reserved.)

This study examined the role of Tfh and Treg associated molecules also known as checkpoint molecules, their ligands, and IL-21 in myasthenia gravis (MG) pathogenesis. Serum levels of sPD-1, sPD-L1, sICOS, sICOSLG, sCTLA4, and IL-21 were measured in 39 patients with acetylcholine receptor (AChR) antibody-positive generalized MG and 27 controls. sPD-1 and IL-21 levels were higher in MG patients than in controls. Additionally, sPD-1 levels correlated positively with the levels of IL-21, sICOSLG, sCTLA4, and AChR antibody titers. sICOS are correlated with MGADL and AChR antibody titers. These Tfh associated molecules could be used as biomarkers of MG disease activity., Competing Interests: Declaration of Competing Interest None., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Immune-mediated necrotizing myopathy (IMNM) is a pathologically defined diagnosis of idiopathic inflammatory myopathies. Adequate studies on cytokines of IMNM is lacking. We measured serum levels of 27 cytokines/chemokines in 22 IMNM patients, 10 sporadic inclusion body myositis (IBM) patients, and 23 other neurological disorders (ONDs) patients. In IMNM patients, the correlations between clinical features and cytokine/chemokine levels, and changes in cytokine/chemokine levels after immunosuppressive therapy were examined. Compared with ONDs patients, IMNM patients had significantly increased serum levels of several cytokines. In particular, IP-10 and MIP-1α levels were prominently increased, decreased after immunosuppressive-therapy, and correlated with serum creatine kinase levels. IP-10 and MIP-1α could play important roles in the IMNM pathogenesis., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Myasthenia gravis (MG), a neuromuscular junction disorder, is caused by pathogenic autoantibodies. Interleukin-6 (IL-6) plays important roles in T helper 17 (Th17), T follicular helper (Tfh), and B cell activations as well as in antibody production. This study aimed to evaluate the clinical significance of serum IL-6 level as a biomarker of disease activity in patients with anti-acetylcholine receptor (AChR) antibody-positive MG. In the present study, serum IL-6 levels were measured in 93 treatment-naïve patients with anti-AChR antibody-positive MG and compared with those in 101 controls. Moreover, correlations between serum IL-6 levels and clinical characteristics were analyzed. Serum IL-6 levels were significantly higher in patients with anti-AChR antibody-positive MG than in controls (median [interquartile range], 2.5 [1.5-8.3] pg/mL vs. 1.5 [1.5-3.2] pg/mL, P < 0.001). The serum levels were correlated with the MG Foundation of America clinical classification (Spearman's ρ = 0.27; P < 0.01) and decreased following immunosuppressive treatment in parallel with disease activity (P = 0.01). In conclusion, IL-6 is involved in the pathogenesis of anti-AChR antibody-positive MG and could be a therapeutic target in MG., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Myasthenia gravis (MG) is an autoantibody-mediated disease of the neuromuscular junction. The neuromuscular junction damage associated with MG is caused by anti-acetylcholine receptor (AChR) antibody and complements. Recently, eculizumab (an anti-C5 monoclonal antibody) was approved for patients with anti-AChR antibody-positive generalized refractory MG. Here, we report a Japanese man with MG who well responded to eculizumab, but experienced acute severe worsening of myasthenic symptoms 2 months after its discontinuation. Plasmapheresis did not improve his symptoms; hence, eculizumab was re-administered, resulting in a dramatic response within a week. This is an informative case because eculizumab discontinuation in patients with MG has been very rarely reported. If eculizumab treatment is clinically well effective and AChR antibody titer does not decrease, clinicians should be aware that acute and critical deterioration of MG may occur after the eculizumab discontinuation., (Copyright © 2020 Elsevier B.V. All rights reserved.)

In demyelinating polyneuropathies, distribution patterns of demyelination reflect underlying pathogenesis. Median and ulnar nerve conduction studies were reviewed in 85 typical chronic inflammatory demyelinating polyneuropathy (CIDP) patients and 29 multifocal acquired demyelinating sensory and motor neuropathy (MADSAM). Distal latencies were prolonged in typical CIDP and near normal in MADSAM. Abnormal amplitude reductions in the nerve trunks were more frequent in MADSAM than typical CIDP. Presumably because the blood-nerve barrier is anatomically deficient at the distal nerve terminals, antibody-mediated demyelination is a major pathophysiology in typical CIDP. In contrast, blood-nerve barrier breakdown is likely to be predominant in MADSAM., Competing Interests: Declaration of Competing Interest None declared., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Complement-dependent disruption of motor endplate is detected in anti-acetylcholine receptor (AChR) antibody-positive myasthenia gravis (MG). We measured serum AChR α1 subunit protein levels, which may be associated with neuromuscular damage, in 55 patients with MG (47 were seropositive and 8 were negative) and in 20 controls. Serum AChR α1 subunit protein concentrations were higher in patients with anti-AChR antibody-positive MG than those in controls (P = .04), were negatively correlated with MG activities of daily living score (P = .01), and tended to be higher in ocular MG than in generalized MG. AChR α1 subunit protein elevation may be related to seropositive MG pathogenesis, especially in the ocular type., (Copyright © 2019 Elsevier B.V. All rights reserved.)

To illustrate the accuracy of the fluorescence-activated cell sorting cell-based assay (FACS-CBA) and to detect anti-myelin oligodendrocyte glycoprotein (MOG) antibodies and ascertain the optimal method for positivity judgement, referencing the findings of microscopic CBA. We tested serum anti-MOG antibodies in 57 patients with central nervous system inflammatory disorders (CIDs), 30 healthy controls (HCs), and 63 disease controls (DCs) by FACS-CBA. To assess the diagnostic performance of 2 positive judgement methods for FACS-CBA, we evaluated the ratio of positive cells (RPC) and median fluorescence intensity (MFI ratio ); samples from 57 CIDs and 3 antiaquaporin-4 antibody-positive patients whose anti-MOG antibody levels were relatively high but negative by FACS-CBA were tested by microscopic CBA. Blinded to the RPC and MFI ratio results, we classified the acquired dot plot into 3 patterns-"upright," "broadband," and "oblique"-as pattern analysis. The sample with the highest RPC in CIDs was subjected to serial dilution analysis. Finally, we analyzed the clinical and laboratory data of anti-MOG antibody-positive patients in the acute phase. Referencing results by microscopic CBA and receiver-operating characteristic curve analysis, the area under the curve, sensitivity, specificity, and cutoff value were 0.952, 92%, 94%, and 1.52 for RPC and 0.931, 79%, 94%, and 6.39 for MFI ratio , respectively, suggesting the optimality of RPC for positive judgement. Titers by microscopic CBA analysis significantly correlated with RPC (P = .031). In the validation study, the positive rate of RPC for anti-MOG antibodies was 42.1% in CIDs, but 0% in HCs and DCs (both P < .001). In the pattern analysis, all anti-MOG antibody-positive patients but none of the HCs and DCs exhibited the "oblique" pattern. Serial dilution curve analysis fit a quaternary polymodal. FACS-CBA using RPC analysis for anti-MOG antibodies displayed relatively higher specificity, sensitivity, and semiquantitative property, indicating it could become another acceptable test to detect anti-MOG antibodies., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Objective: To identify autoantibodies using sera from ALS patients and elucidate their roles in disease pathology., Methods: An immunological screening was performed with a phage expression library SEREX method using sera from 3 ALS patients to identify ALS-related autoantibodies. Levels of antibodies identified by SEREX were measured in 33 ALS patients and 30 normal controls (NCs) by AlphaLISA using recombinant non-full-length proteins. The results were then validated by ELISA using full-length proteins in 71 ALS patients, 30 NCs and 34 disease controls (DCs). The relationship between the titres and clinical profiles of ALS patients were examined., Results: Four autoantibodies identified by SEREX were proteasome subunit alpha type 7 (PSMA7), vimentin, hydroxymethylbilane synthase and TBC1 domain family member 2 (TBC1D2). AlphaLISA revealed that only the anti-PSMA7 and anti-TBC1D2 levels were significantly different between the ALS and NCs groups. ELISA showed that only the levels of antibody against PSMA7, involved in protein degradation by the ubiquitin-proteasome pathway (UPP), were higher in the ALS group than both the NC (P < .01) and DC (P = .034) groups. Anti-PSMA7 levels tended to be negatively correlated with the logarithm of disease duration (P = .052) and were significantly positively correlated with the logarithm of creatine kinase levels (P = .011). The anti-PSMA7 antibody levels were different between patients with and without dysphagia (P < .01)., Conclusions: Serum anti-PSMA7 antibody might be a disease-promoting factor in early-stage ALS and might be a biomarker of ALS. Anti-PSMA7 autoantibody might contribute to the pathogenesis of ALS, possibly via its role in the UPP., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Serum soluble CD40 ligand (sCD40L) has been reported to positively correlate with the albumin quotient, a marker of blood-brain barrier (BBB) breakdown, in patients with multiple sclerosis (MS). To clarify the mechanisms of sCD40L in MS pathophysiology, sCD40L was administered to experimental autoimmune encephalomyelitis (EAE) mice and a human brain microvascular endothelial cell (HBMEC)-based BBB model. The high-dose sCD40L group showed a worse EAE score than the low-dose and control groups. BBB permeability was increased by administering sCD40L in a HBMEC-based BBB model. Thus, sCD40L induces more severe inflammation in the central nervous system by disrupting the BBB., (Copyright © 2018. Published by Elsevier B.V.)

Previously, we identified anti-Talin-1 antibodies in the serum of MS. In this case, we measured the serum soluble Talin-1 (sTalin-1) levels by enzyme-linked immunosorbent assay. The serum sTalin-1 levels were significantly higher in 40 patients with MS than in 43 normal controls and in the acute phase of disease than in the remission phase. Interestingly, serum sTalin-1 levels were associated with a sustained increase in disability after MS attack but not with serum anti-Talin-1 antibody levels. sTalin-1 may be a biomarker for the acute phase of MS and may be used for the short-term prognosis of MS., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Soluble CD40 ligand (sCD40L) is reported to disrupt the blood-brain barrier (BBB). Cerebrospinal fluid (CSF) and serum sCD40L levels were measured in 29 multiple sclerosis (MS), 29 neuromyelitis optica spectrum disorder (NMOSD), and 27 disease control (DC) patients. In MS, serum sCD40L levels were higher than in DCs and positively correlated with the CSF/serum albumin ratio (Qalb). In NMOSD, CSF sCD40L levels were significantly increased compared to DCs, and were correlated to Qalb, CSF cell counts, protein concentrations, and interleukin-6 levels. sCD40L could be involved in BBB disruption in MS, whereas it may contribute to CNS inflammation in NMOSD., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Juvenile muscular atrophy of the distal upper extremity (Hirayama disease) is characterized by adolescent-onset muscular weakness of the distal upper limb. Several studies showed the contribution of atopic disposition and hyperIgEaemia to the disease process, but it has not been well clarified. To identify cytokine and chemokine profiles in Hirayama disease, serum samples were analyzed using multiplex magnetic bead-based assay. Eotaxin, MCP-1 and RANTES levels were significantly higher in Hirayama disease (N=11) than in normal controls (N=12). These chemokines are associated with inflammatory cell recruitment. Allergic inflammation may involve in the pathogenesis of Hirayama disease., (Copyright © 2016 Elsevier B.V. All rights reserved.)

Extracellular peroxiredoxin 5 (PRX5) is known to be an inflammatory mediator. The serum PRX5 levels of 40 patients with anti-acetylcholine receptor antibody-positive MG and those of 40 controls were measured. PRX5 levels in patients with MG were higher than those in the controls (P=0.045). Thymoma-associated MG patients showed higher PRX5 levels than late-onset MG patients and controls (P<0.05). There were significant associations between the serum PRX5 levels and high mobility group box 1 levels. PRX5 elevation in MG could be related to the neuromuscular junction breakdown and plays a pivotal role in the pathogenic inflammation of MG., (Copyright © 2015. Published by Elsevier B.V.)

To identify the target molecules of chronic inflammatory demyelinating polyneuropathy (CIDP), we used proteomic-based approach in the extracted proteins from porcine cauda equina. Two of 31 CIDP patients had markedly elevated serum autoantibodies against vinculin, a cell adhesion protein. Both of the patients with anti-vinculin antibodies had similar clinical manifestation, which are compatible with those of "typical" CIDP. Immunocytochemistry showed that vinculin was stained at the myelin sheath of the sciatic nerves by serum samples. Our results suggest that vinculin is a possible immunological target molecule in a subpopulation of typical CIDP patients., (Copyright © 2015 Elsevier B.V. All rights reserved.)

In the pathogenesis of multiple sclerosis (MS), B cell/antibody-related mechanisms have recently received attention. To investigate the role of autoantibody in MS, we performed SEREX which can identify autoantibody cyclopedically. We identified serum antibodies against cytoskeletal protein talin1, and the levels of whom were remarkably higher in 39 MS than 43 normal controls (P < 0.01) and 35 disease controls (P = 0.06), and in MS patients without oligoclonal bands than ones with them. Moreover, we found negative-correlations between serum anti-talin1 antibody and IgG index in MS (P = 0.03). Anti-talin1 antibody exists in MS patients' sera, which may have some protective factor., (Copyright © 2015 Elsevier B.V. All rights reserved.)

To identify serum cytokine networks specific to chronic inflammatory demyelinating polyneuropathy (CIDP), serum samples of two subgroups (18 patients with typical CIDP and 12 patients with multifocal acquired demyelinating sensory and motor neuropathy [MADSAM]) were analyzed with multiplex magnetic bead-based cytokine assay. TNF-α, HGF, MIP-1β and IL-1β levels were significantly higher in total CIDP patients than in normal controls. Of these, HGF levels were elevated in typical CIDP patients, but not in MADSAM patients. Patients with high HGF levels showed good responses to steroid treatment. Different cytokine profiles among the CIDP subtypes presumably reflect differences in pathophysiology., (Copyright © 2014 Elsevier B.V. All rights reserved.)

To detect serum biomarkers associated with disease activity in relapsing-remitting multiple sclerosis (MS). We studied serum low-molecular peptide profiling of MS patients and normal controls comprehensively by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Serum level of 1741 Da peptide was increased at the time of clinical relapse in patients than in normal controls and returned toward normal during remission. Tandem mass spectrometry analysis revealed that the peptide was a fragment of complement C4 (NGFKSHALQLNNRQI). This fragment peptide could be a possible marker of disease activity. It may reflect complement activation in the pathogenesis of MS., (Copyright 2009 Elsevier B.V. All rights reserved.)

NMO-IgG, a disease-specific autoantibody for neuromyelitis optica, recognizes aquaporin-4 (AQP4) and has been examined by indirect immunofluorescence assay. We developed an enzyme-linked immunosorbent assay (ELISA) to detect anti-AQP4 antibodies by establishing methods for expression in a baculovirus system and purification of recombinant AQP4 as antigen. Elevated anti-AQP4 antibody titers in serum were found in 15 (71%) of 21 patients with neuromyelitis optica, 4.3% of 46 patients with multiple sclerosis, none of 51 normal controls, and 2.6% of 115 patients with other neurological diseases. The ELISA system can be substituted for the conventional NMO-IgG assay.

Twenty-eight patients suffered Campylobacter jejuni enteritis after eating raw chicken. Among them, only one patient developed Bickerstaff's brainstem encephalitis, who carried anti-GQ1b IgG antibodies. In contrast, none of the others did the autoantibodies. C. jejuni was cultured from all stool samples from five patients with enteritis alone. All the isolates had the same genotype, cst-II (Asn51), which are characteristic of strains isolated from Bickerstaff's brainstem encephalitis. These findings suggest that host susceptibility may play a role in inducing the production of anti-ganglioside antibodies and the development of Bickerstaff's brainstem encephalitis.

Anti-ganglioside GQ1b antibody induces neuromuscular blocking on mouse phrenic nerve-diaphragm preparations. Several reports suggest that patients with this antibody show abnormal neuromuscular transmission in the facial or limb muscles, but limb muscle weakness is unusual in Miller Fisher syndrome that is often associated with anti-GQ1b antibody. To determine whether anti-GQ1b sera affect neuromuscular transmission in human limb muscles, axonal-stimulating single fiber electromyography was performed in the forearm muscle of seven patients with anti-GQ1b antibody. All showed normal jitter and no blocking. Anti-GQ1b antibody does not affect neuromuscular transmission in human limb muscles. The different findings in mouse and human may be explained by the extent of expression of GQ1b on the motor nerve terminals in the muscle examined.

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.