Anti-AQP4 autoantibodies promote ATP release from astrocytes and induce mechanical pain in rats.

BACKGROUND: Intractable neuropathic pain is a common symptom of neuromyelitis optica spectrum disorder (NMOSD). However, the underlying mechanism of NMOSD pain remains to be elucidated. In this study, we focused on ATP, which is one of the damage-associated molecular patterns, and also a well-recognized molecule involved in peripheral neuropathic pain. METHODS: We assessed the development of pain symptoms by injecting anti-AQP4 recombinant autoantibodies (rAQP4 IgG) into rat spinal cords. We incubated HEK293 cells expressing AQP4 (HEK-AQP4) and rat astrocytes with rAQP4 IgG and assessed the level of ATP in the supernatant. We performed transcriptome analysis of the spinal cords injected with rAQP4 IgG. Pharmacological inhibition was also applied to investigate the involvement of ATP in the development of neuropathic pain in our rat model. The ATP concentration within the cerebrospinal fluid was examined in patients with NMOSD and other neurological diseases. RESULTS: Development of mechanical allodynia was confirmed in rAQP4 IgG-treated rats. AQP4-Ab-mediated extracellular ATP release from astrocytes was observed in vitro, and pharmacological inhibition of ATP receptor reversed mechanical allodynia in the rAQP4 IgG-treated rats. Furthermore, transcriptome analysis revealed elevation of gene expressions related to several ATP receptors including P2rx4 and IL1B in the spinal cord of rAQP4 IgG-treated rats. In patients, CSF ATP concentration was significantly higher in the acute and remission phase of NMOSD than in multiple sclerosis or other neurological disorders. CONCLUSION: Anti-AQP4 antibody was shown to induce the release of extracellular ATP from astrocytes. The ATP-mediated development of mechanical allodynia was also suggested in rats treated with anti-AQP4 antibody. Our study indicates the pivotal role of ATP in the pain mechanism of NMOSD.

Sema4A is implicated in the acceleration of Th17 cell-mediated neuroinflammation in the effector phase.

BACKGROUND: Sema4A is a regulator of helper T cell (Th) activation and differentiation in the priming phase, which plays an important role in the pathogenesis of experimental autoimmune encephalomyelitis (EAE) and multiple sclerosis (MS). However, the role of Sema4A in the effector phase remains elusive. We aimed to investigate the role of Sema4A at the effector phase in adoptively transferred EAE model. Clinical features and cytokine profiles of MS patients with high Sema4A levels were also examined in detail to clarify the correlation between Sema4A levels and disease activity of patients with MS. METHODS: We adoptively transferred encephalitogenic Th1 or Th17 cells to wild type (WT) or Sema4A-deficient (Sema4A KO) mice and assessed severity of symptoms and cellular infiltration within the central nervous system (CNS). In addition, we analyzed clinical and radiological features (n = 201), levels of serum IFN-γ and IL-17A (n = 86), complete remission ratio by IFN-ß (n = 38) in all of relapsing-remitting multiple sclerosis (RRMS) patients enrolled in this study. RESULTS: Sema4A KO recipient mice receiving Th17-skewed WT myelin oligodendrocyte glycoprotein (MOG)-specific encephalitogenic T cells showed a significant reduction in the clinical score compared to the WT recipient mice. However, Sema4A KO recipient mice showed similar disease activity to the WT recipient mice when transferred with Th1-skewed encephalitogenic T cells. Bone marrow chimeric study indicated that Sema4A expressed on hematopoietic cells, but not the CNS resident cells, are responsible for augmenting Th17-mediated neuroinflammation. Additionally, in contrast to comparable IFN-γ levels, IL-17A is significantly higher in RRMS patients with high Sema4A level than those with low Sema4A patients with high Sema4A levels showed earlier disease onset, more severe disease activity and IFN-ß unresponsiveness than those with low Sema4A levels. CONCLUSIONS: Sema4A is involved not only in the Th cell priming but also in the acceleration of Th17 cell-mediated neuroinflammation in the effector phase, which could contribute to the higher disease activity observed in RRMS patients with high serum Sema4A levels.

Cerebrospinal fluid mitochondrial DNA in neuromyelitis optica spectrum disorder.

BACKGROUND: Neuromyelitis optica spectrum disorder (NMOSD) is an inflammatory disease of the central nervous system. Although complement-dependent astrocyte damage mediated by anti-aquaporin 4 autoantibody (AQP4-Ab) is well acknowledged to be the core of NMOSD pathogenesis, additional inflammatory cascades may contribute to the establishment of lesion formation. Thus, in this study, we investigated the possible pathogenic role of immune-reactive mitochondrial DNA (mtDNA) in cerebrospinal fluid (CSF) of NMOSD patients. METHODS: Using quantitative polymerase chain reaction, we measured extracellular mtDNA levels in CSF of NMOSD patients positive for AQP4-Ab. Patients with multiple sclerosis or other neurological diseases were examined as controls. Pre- and post-treatment extracellular mtDNA levels were also compared in the NMOSD group. Extracellular mtDNA release from human astrocytes was analyzed in vitro utilizing NMOSD sera, and interleukin (IL)-1ß production was measured in supernatants of mixed glial cells stimulated with DNA fraction of CSF derived from NMOSD patients. Furthermore, specific innate immune pathways mediating the IL-1ß production by mtDNA were investigated in peripheral blood mononuclear cells with selective inhibitors of Toll-like receptor 9 (TLR9) and NOD-like receptor protein 3 (NLRP3) inflammasomes. RESULTS: Extracellular mtDNA level was specifically elevated in acute phase of NMOSD CSF. In vitro studies provided the evidence that mtDNA is released from human astrocytes by NMOSD sera. In addition, DNA fraction isolated from NMOSD CSF promoted secretion of IL-1ß from mixed glial cells. Selective inhibition of TLR9 and NLRP3 inflammasomes revealed that mtDNA-mediated IL-1ß production depends on specific innate immune pathways. CONCLUSION: Extracellular mtDNA is specifically elevated in the CSF of patients with acute phase NMOSD, and mtDNA released by AQP4-Ab-mediated cellular damage elicits the innate immune cascades via TLR9 and NLRP3 inflammasomes pathways. Our study highlights mtDNA-mediated innate immune pathways as a novel therapeutic target for future treatment of NMOSD patients.

Herpes zoster laryngitis in a patient treated with fingolimod.

Development of treatment with immunomodulatory agents has improved prognosis of various autoimmune-related diseases. A sphingosin-1-phosphate receptor modulator, or fingolimod, is the first licensed oral drug for relapsing-remitting multiple sclerosis. The agent reduces circulating lymphocytes by trapping T cells in lymph nodes, possibly leading to reactivation of latent viruses. A 41-year-old Japanese woman who had been treated with fingolimod for 2 years presented with unilateral sore throat. Laryngoscopy revealed exudates unilaterally emerging on the left side of her supraglottic region. Serum level of the varicella zoster virus (VZV)-specific IgG was markedly elevated, and a result of genome sequence using the exudates demonstrated VZV as a possible causative pathogen. Fingolimod therapy was discontinued and the patient was successfully treated with intravenous acyclovir. This is the first reported case of fingolimod-associated herpes zoster laryngitis, in which the local VZV reactivation was demonstrated by next-generation sequencing technology. The present case highlights that the occurrence of VZV reactivation should be recalled in any patients undergoing fingolimod therapy.

Case report: The histopathological analyses of two myelin oligodendrocyte glycoprotein antibody-associated diseases with a distinctive linear radiating gadolinium enhancement on MRI.

Myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) has highly heterogeneous clinical presentations, in which encephalitis is an important phenotype. Moreover, MOGAD has been reported to exhibit diverse imaging findings. However, there have been no previous reports of cases with perivascular radial gadolinium enhancement in periventricular regions, commonly reported in autoimmune glial fibrillary acidic protein (GFAP) astrocytopathy. In this paper, we present two cases of MOGAD with this MRI feature, both of which underwent brain biopsy for the lesions. Brain biopsies revealed perivenous demyelination and inflammation consistent with acute disseminated encephalomyelitis (ADEM), with pronounced axonal damage in Case 1 and minimal axonal involvement in Case 2. Case 1 exhibited more severe cerebral atrophy than Case 2, correlating with the extent of axonal damage. Through these cases, we highlight the heterogeneity of radiological manifestations of MOGAD, expanding the spectrum beyond previously defined MRI patterns. Furthermore, histopathological analysis revealed distinct axonal involvement as a potential prognostic marker of brain atrophy. These observations emphasize the importance of considering MOGAD in the differential diagnosis, even in cases with atypical imaging findings, and highlight the significance of brain biopsy in guiding both diagnosis and prognosis.

A case of Adult-onset Acute Flaccid Myelitis Accompanied by Rhombencephalitis which First Presented with Prominent Psychiatric Symptoms and Dysautonomia Mimicking Anti-N-methyl-d-aspartate Receptor Encephalitis.

A 44-year-old woman with a subacute onset of an altered mental status, urinary retention, and fluctuating blood pressure was initially diagnosed with anti-N-methyl-d-aspartate receptor (NMDAR) encephalitis, meeting the criteria of Graus et al. Cardiac arrest occurred, which required pacemaker placement. She subsequently showed profound flaccid limb paralysis, with magnetic resonance imaging demonstrating focal necrotic lesions localized in the anterior horn of the longitudinal segments of the spinal cord and in the pontine tegmentum. Enteroviruses or autoimmune encephalitis-associated autoantibodies were not detected. We herein report a case of acute flaccid myelitis with profound psychiatric symptoms and dysautonomia, resembling NMDAR encephalitis.

Identification of double-stranded DNA in the cerebrospinal fluid of patients with acute neuromyelitis optica spectrum disorder.

Neuromyelitis optica spectrum disorder (NMOSD) is an inflammatory disease of the central nervous system (CNS) characterized by severe myelitis and optic neuritis. Double-stranded DNA (dsDNA) is involved in the pathogenesis of various autoimmune diseases, such as systemic lupus erythematosus. However, its role in NMOSD remains unclear. In this study, the concentration of dsDNA in the cerebrospinal fluid (CSF) was quantified in 23 patients with NMOSD and 16 patients with other neurological diseases (ONDs). CSF dsDNA levels in patients with NMOSD (median: 0.03 ng/µL) were significantly higher than those in patients with ONDs (median: 0.01 ng/µl). CSF dsDNA levels showed no significant difference before and after treatment. Elevation of CSF dsDNA levels may suggest its essential role in the augmentation of CNS inflammation in patients with NMOSD.

RGMa collapses the neuronal actin barrier against disease-implicated protein and exacerbates ALS.

Repulsive guidance molecule A (RGMa) was originally identified as a neuronal growth cone-collapsing factor. Previous reports have demonstrated the multifunctional roles of RGMa mediated by neogenin1. However, the pathogenic involvement of RGMa in amyotrophic lateral sclerosis (ALS) remains unclear. Here, we demonstrated that RGMa concentration was elevated in the cerebrospinal fluid of both patients with ALS and transgenic mice overexpressing the mutant human superoxide dismutase1 (mSOD1 mice). Treatment with humanized anti-RGMa monoclonal antibody ameliorated the clinical symptoms in mSOD1 mice. Histochemical analysis revealed that the anti-RGMa antibody significantly decreased mutant SOD1 protein accumulation in the motor neurons of mSOD1 mice via inhibition of actin depolymerization. In vitro analysis revealed that the anti-RGMa antibody inhibited the cellular uptake of the mutant SOD1 protein, presumably by reinforcing the neuronal actin barrier. Collectively, these data suggest that RGMa leads to the collapse of the neuronal actin barrier and promotes aberrant protein deposition, resulting in exacerbation of the ALS pathology.

Cryptogenic new-onset refractory status epilepticus responded to anti-interleukin-6 treatment.

OBJECTIVE: The aim of this case report was to describe a potential anti-interleukin (IL)-6 treatment for cryptogenic new-onset refractory status epilepticus (C-NORSE). BACKGROUND: Although an underlying immune-mediated pathogenesis is considered present in some C-NORSE cases, many cases do not respond to classical immunotherapies. CASE REPORT: We describe the case of a 46-year-old woman with C-NORSE who achieved cessation of long-lasting status epilepticus following administration of tocilizumab, an IL-6 receptor-blocking antibody, although the final outcome was poor. CONCLUSIONS: Anti-IL-6 treatment may prove effective in stopping status epilepticus in some C-NORSE cases.

Erdheim-Chester Disease Involving the Central Nervous System with Latent Toxoplasmosis.

Erdheim-Chester disease (ECD) is a rare, non-Langerhans cell histiocytosis characterized by the infiltration of foamy histiocytes into multiple organs. We herein report a case of ECD with central nervous system (CNS) involvement in a 63-year-old man who also presented a positive result for Toxoplasma gondii nested polymerase chain reaction testing of cerebrospinal fluid. Since anti-Toxoplasma treatment proved completely ineffective, we presumed latent infection of the CNS with T. gondii. This case suggests the difficulty of distinguishing ECD with CNS involvement from toxoplasmic encephalitis and the possibility of a relationship between the pathogeneses of ECD and infection with T. gondii.

Astrocyte metabolism in multiple sclerosis investigated by 1-C-11 acetate PET.

This study was aimed at evaluating the metabolism of reactive astrocytes in the brains of patients with multiple sclerosis by quantitative 1-C-11 acetate positron emission tomography (PET). Magnetic resonance imaging and 1-C-11 quantitative PET were performed in eight patients with multiple sclerosis and 10 normal control subjects. The efflux rate (k2) of 1-C-11 acetate, which reportedly reflects the metabolic rate of 1-C-11 acetate, was calculated based on the one-tissue compartmental model. Fractional anisotropy was also determined to evaluate the integrity of the neuronal tracts. The values of k2 in the patients with multiple sclerosis were significantly higher than those in the normal control subjects, in both the white matter (p = 0.003) and the gray matter (p = 0.02). In addition, the white matter/gray matter ratio of k2 was significantly higher in the multiple sclerosis patients than in the normal control subjects (p = 0.02). Voxel-based statistical analysis revealed most prominent increase in k2 in the neuronal fiber tracts, as well as decrease in fractional anisotropy in them in the multiple sclerosis patients. The present study clarified that the pathological changes associated with astrocytic reactivation in multiple sclerosis patients could be visualized by quantitative 1-C-11 acetate PET.

Anti-MuSK Positive Myasthenia Gravis with Anti-Lrp4 and Anti-titin Antibodies.

In addition to muscle nicotinic acetylcholine receptor (AChR) and muscle-specific kinase (MuSK), low-density lipoprotein receptor (Lrp4) has recently been discovered to be a novel target antigen among patients with seronegative myasthenia gravis (MG). We herein report the findings of a 62-year-old patient who showed positivity for anti-MuSK, anti-Lrp4, and anti-titin antibodies. The patient developed MG crisis following a 10-year history of intermittent double vision with ptosis, and a 7-year history of dropped head. Our detailed clinical, laboratory, and therapeutic descriptions highlight its unique characteristics of anti-MuSK-antibody positive MG accompanied by anti-Lrp4 and anti-titin antibodies.

[A case of Alexander disease presented with dystonia of lower limb and decreased dopaminergic uptake in dopamine transporter scintigraphy].

A 50-year-old woman developed gait disturbances and dysarthria since the past 2 years. She also presented with dystonia and hypokinesia of her left lower limb, and orthostatic hypotension. The dopamine transporter SPECT with 123I ioflupane showed abnormal scans in bilateral striatum. Cerebral MRI revealed atrophy and signal changes in the medulla and spinal cord, from which Alexander disease (AxD) was suspected. Consequently, we checked the Glial fibrillary acidic protein (GFAP) gene. The analysis of the gene detected a heterozygous c.219G>T mutation, which was the first mutation reported in Japan, and finally she was diagnosed with AxD. Dystonia is relatively rare in AxD patients, but this case demonstrated that AxD should be listed in the differential diagnosis of extrapyramidal syndromes with abnormalities of the medulla and spinal cord on MRI.

C1-inhibitor Deficiency Induces Myositis-like Symptoms Via the Deposition of the Membrane Attack Complex in the Muscle.

We herein report a 56-year-old Japanese woman who had been diagnosed with hereditary angioedema. She experienced progressing muscle weakness and pain in the upper and lower extremities. Blood tests revealed a marked increase in creatine kinase levels; however, myositis-specific autoantibodies were not detected. Serum C1-inhibitor activity and C4 levels were low. A muscle biopsy showed mild muscle fiber necrosis and C5b-9 deposition in the endomysial capillary vessel walls and sarcolemma, mimicking necrotizing myopathy. These results suggest that C1-inhibitor deficiency induces myositis-like symptoms through the activation of the complement pathway and deposition of the membrane attack complex in the muscles.

Mitochondrial DNA enhance innate immune responses in neuromyelitis optica by monocyte recruitment and activation.

Although recent studies indicate the involvement of monocytes in accelerating the lesion formation of neuromyelitis optica spectrum disorder (NMOSD), the precise mechanism of the innate immune system activation remains elusive. Thus, in this study, we aimed to clarify the mechanisms of NMOSD pathogenesis from the viewpoint of innate immunity activation. We established anti-AQP4 recombinant autoantibodies (Ab) from plasmablasts in NMOSD patient's CSF. Human astrocytes treated with anti-AQP4 Ab produced a significant amount of CCL2 and contributed to the efficient recruitment of monocytes. Moreover, mitochondrial DNA (mtDNA), which activated monocytes via Toll-like receptor 9 (TLR9), was released from astrocytes treated with anti-AQP4 Ab. MtDNA further enhanced CCL2 production by monocytes, and it was demonstrated that mtDNA concentration correlated with the efficiency of monocyte recruitment in the CSF of NMOSD patients. In conclusion, these observations highlight that mtDNA which was released from astrocytes damaged by anti-AQP4 Ab has a central role in establishing the inflammatory loop of monocyte recruitment and activation via an innate immunity pathway.

Risk of stroke early after implantation of a left ventricular assist device.

OBJECTIVE: Stroke is one of the major adverse events after left ventricular assist device implantation. Risk of stroke is the highest immediately after left ventricular assist device implantation and then increases again in chronic periods. There is no study that has analyzed risk factors for stroke in acute phase. We investigated the risk factors for stroke in the acute phase after left ventricular assist device implantation in the present study. METHODS: Between October 2005 and December 2016, 158 consecutive patients (mean age, 43 ± 14 years; 34% were women) underwent continuous-flow left ventricular assist device (50 HeartMate II [Abbott Medical, Abbott Park, Ill], 38 DuraHeart [Terumo Heart, Ann Arbor, Mich], 33 Jarvik2000 [Jarvik Heart, New York, NY], 23 EVAHEART [Sun Medical, Moriyama City, Japan], 14 HeartWare [Framingham, Mass]) implantation in our institution. We analyzed the risk factors for a symptomatic stroke within 90 days after left ventricular assist device implantation. RESULTS: Stroke occurred in 28 patients in the acute phase after left ventricular assist device implantation. Multivariate analysis revealed that low cardiac output (odds ratio, 0.25; 0.07-0.92; P = .024) during postoperative 12 to 24 hours was the only independent risk factor for stroke in the acute phase. Patients with stroke in the acute phase had higher serum lactate dehydrogenase levels at any point until postoperative 14 days. Patients with the HeartMate II device particularly showed a statistically significant negative relationship between cardiac output during postoperative 12 to 24 hours and serum lactate dehydrogenase levels at postoperative 14 days (r = -0.313, P = .03). CONCLUSIONS: Our study demonstrated that patients with perioperative lower cardiac output and higher lactate dehydrogenase level developed stroke in the acute phase after left ventricular assist device implantation. These results suggested that maintenance of sufficient left ventricular assist device flow is important in prevention of stroke, which may be related to subclinical pump thrombosis.

Single injection of sustained-release prostacyclin analog ONO-1301-MS ameliorates hypoxic toxicity in the murine model of amyotrophic lateral sclerosis.

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease characterized by several pathologies including oxidative stress, apoptosis, neuroinflammation, and glutamate toxicity. Although multiple reports suggest that ischemia and hypoxia in the spinal cord plays a pivotal role in the pathogenesis of ALS, the precise role of hypoxia in disease progression remains unknown. In this study, we detected higher expression levels of Hypoxia-inducible factor 1-alpha (HIF-1α), a key regulator of cellular responses to hypoxia, in the spinal cord of ALS patients and in the transgenic mice overexpressing the familial ALS-associated G93A SOD1 mutation (mSOD1G93A mice) compared to controls. Single subcutaneous administration of sustained-release prostacyclin analog ONO-1301-MS to mSOD1G93A mice abrogated the expression of HIF-1α in their spinal cords, as well as erythropoietin (EPO) and vascular endothelial growth factor (VEGF), both of which are downstream to HIF-1α. Furthermore, ONO-1301-MS increased the level of mature brain-derived neurotrophic factor (BDNF) and ATP production in the spinal cords of mSOD1G93A mice. At late disease stages, the motor function and the survival of motor neurons of ONO-1301-MS-treated mSOD1G93A mice was significantly improved compared to vehicle-treated mSOD1G93A mice. Our data suggest that vasodilator therapy modulating local blood flow in the spinal cord has beneficial effects against ALS disease progression.

[A case of chronic inflammatory demyelinating polyradiculoneuropathy presenting recurrent attacks associated with pregnancies].

At 37 years of age, the patient initially presented with symptoms of chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) during her 1st pregnancy. She was treated with intravenous immunoglobulin (IVIg), and showed favorable recovery, becoming almost asymptomatic by the age of 38. At 39 years of age, during her puerperal period of her second pregnancy, she developed symmetrical muscle weakness and sensory disturbance of the upper and lower limbs. Nerve conduction studies revealed diffuse demyelination of peripheral nerves, and she was diagnosed with recurrence of CIDP. Once again, she showed remarkable improvement after IVIg therapy, and she has remained asymptomatic without the induction of preventative therapies. Recurrence of CIDP triggered in accordance with multiple pregnancies is extremely rare, and its clinical and electrophysiological features are presented in this report.

Beneficial effects of fingolimod in MS patients with high serum Sema4A levels.

We previously demonstrated that patients with multiple sclerosis (MS) of high serum Sema4A levels are resistant to IFN-ß therapy. To further elucidate the role of serum Sema4A as a biomarker for therapeutic stratification in MS patients, it is important to clarify the efficacy of other disease-modifying drugs (DMD) in those with high serum Sema4A levels. Thus, in this study we investigated whether fingolimod has beneficial effects on MS patients with high Sema4A levels. We retrospectively analyzed annualized relapse rate (ARR) and Expanded Disability Status Scale (EDSS) change in 56 relapsing-remitting multiple sclerosis (RRMS) patients who had been treated with fingolimod, including those who switched from IFN-ß therapy. The levels of Sema4A in the sera were measured by sandwich ELISA. The implications of Sema4A on the efficacy of fingolimod were investigated by administering recombinant Sema4A-Fc and fingolimod to mice with experimental autoimmune encephalomyelitis (EAE). Retrospective analysis of MS cohort (17 high Sema4A and 39 low Sema4A) demonstrated the effectiveness of fingolimod in those with high serum Sema4A levels, showing reduction of ARR (from 1.21 to 0.12) and EDSS progression (from 0.50 to 0.04). Consistent with this observation, improvement in the disease severity of EAE mice receiving recombinant Sema4A-Fc was also observed after fingolimod treatment. These data suggest that fingolimod could serve as a candidate DMD for managing the disease activity of MS patients with high Sema4A levels.

A case of anti-neurofascin 155 antibody-positive combined central and peripheral demyelination successfully treated with plasma exchange.

A 21-year-old man was admitted to our hospital in June 2015. He felt paresthesia of toes in April 2015, which had been spreading upward, and he became difficult to walk in June. Nerve conduction study showed peripheral demyelinating neuropathy that met the diagnostic criteria for chronic inflammatory demyelinating polyneuropathy (CIDP), and the cerebrospinal fluid (CSF) examination revealed the remarkably increased protein level. In addition, magnetic resonance imaging of his brain showed a few plaques in white matter, so he was finally diagnosed with combined central and peripheral demyelination (CCPD). Moreover, anti-neurofascin155 (NF155) antibodies assayed in his serum and CSF turned out to be positive. Although he was treated with intravenous immunoglobulin and intravenous methylprednisolone, his symptoms were not ameliorated. However, plasma exchange therapy was apparently effective, and the titer of anti-NF155 antibody was reduced. Recently, the number of case reports of CIDP with CNS lesions has gradually been increasing, while the information about the diagnosis and the treatment responses are not enough. Thus, we reported our case with CCPD who was successfully treated with plasma exchange.