Network Meta-analysis of Ravulizumab and Alternative Interventions for the Treatment of Neuromyelitis Optica Spectrum Disorder.

INTRODUCTION: Anti-aquaporin-4 antibody-positive (AQP4-Ab+) neuromyelitis optica spectrum disorder (NMOSD) is a complement-mediated autoimmune disease in which unpredictable and relapsing attacks on the central nervous system cause irreversible and accumulating damage. Comparative efficacy of new NMOSD therapies, such as ravulizumab, with established therapies is critical in making informed treatment decisions. METHODS: Efficacy of ravulizumab relative to established AQP4-Ab+ NMOSD treatments, such as eculizumab, inebilizumab, and satralizumab, was evaluated in a Bayesian network meta-analysis (NMA). Data were extracted from trials identified by a systematic literature review. The final evidence base consisted of 17 publications representing five unique and global studies (PREVENT, N-MOmentum, SAkuraSky, SAkuraStar, and CHAMPION-NMOSD). The primary endpoint was time-to-first relapse; other outcomes included annualized relapse rates (ARRs). RESULTS: For patients receiving monotherapy (monoclonal antibody only), ravulizumab was associated with a lower risk of relapse than inebilizumab (hazard ratio [HR] 0.09, 95% credible interval [CrI] 0.02, 0.57) or satralizumab (HR 0.08, 95% CrI 0.01, 0.55) and was comparable to eculizumab (HR 0.86, 95% Crl 0.16, 4.52). Ravulizumab + immunosuppressive therapy (IST) was associated with a lower risk of relapse than satralizumab + IST (HR 0.15, 95% CrI 0.03, 0.78); the comparison with eculizumab + IST suggested no difference. No patients treated with inebilizumab received background IST and were thus excluded from analysis. The ARR with ravulizumab monotherapy was 98% lower compared with inebilizumab (rate ratio [RR] 0.02, 95% Crl 0.00, 0.38) and satralizumab (RR 0.02, 95% Crl 0.00, 0.42) monotherapies. The ARR with ravulizumab ± IST showed the strongest treatment-effect estimates compared with other interventions. CONCLUSION: In the absence of head-to-head randomized controlled trials, NMA results suggest ravulizumab, a C5 inhibitor, is likely to be more effective in preventing NMOSD relapse in patients with AQP4-Ab+ NMOSD when compared with other treatments having different methods of action.

Anti-aquaporin-4 antibody-positive neuromyelitis optica spectrum disorder, also called AQP4-Ab+ NMOSD, is a rare autoimmune disease that causes repeated episodes of symptoms such as blindness, arm/leg weakness, painful spasms, vomiting, and hiccups, among other symptoms. Each episode can cause nervous system damage to worsen, making it more difficult to recover back to regular abilities. Repeated episodes are likely to cause permanent damage, such as blindness and paralysis. Medical treatments that reduce episodes also reduce the damage and the chances symptoms will become permanent. One treatment, ravulizumab, is being studied to treat adults with AQP4-Ab+ NMOSD. This analysis looked at information from published clinical studies to compare ravulizumab with three other treatments (eculizumab, inebilizumab, and satralizumab) to determine how well each treatment reduced NMOSD episodes. There are no studies that have tested all four treatments in one study. Here, the treatments were compared by a method used to estimate the likelihood of a treatment being better than the others. While all four treatments successfully reduced episodes in their own studies, this analysis predicts that ravulizumab would likely be best in preventing episodes compared with inebilizumab or satralizumab when used alone or in combination with other immunosuppressive treatments. These findings, in consideration along with other relevant factors such as cost, safety, dosing delivery method, and frequency of treatment, may help doctors and patients decide what is the best treatment option for each individual patient to prevent attacks in adults with AQP4-Ab+ NMOSD.

Astroglial connexin 43 is a novel therapeutic target for chronic multiple sclerosis model.

In chronic stages of multiple sclerosis (MS) and its animal model, experimental autoimmune encephalitis (EAE), connexin (Cx)43 gap junction channel proteins are overexpressed because of astrogliosis. To elucidate the role of increased Cx43, the central nervous system (CNS)-permeable Cx blocker INI-0602 was therapeutically administered. C57BL6 mice with chronic EAE initiated by MOG35-55 received INI-0602 (40 mg/kg) or saline intraperitoneally every other day from days post-immunization (dpi) 17-50. Primary astroglia were employed to observe calcein efflux responses. In INI-0602-treated mice, EAE clinical signs improved significantly in the chronic phase, with reduced demyelination and decreased CD3+ T cells, Iba-1+ and F4/80+ microglia/macrophages, and C3+GFAP+ reactive astroglia infiltration in spinal cord lesions. Flow cytometry analysis of CD4+ T cells from CNS tissues revealed significantly reduced Th17 and Th17/Th1 cells (dpi 24) and Th1 cells (dpi 50). Multiplex array of cerebrospinal fluid showed significantly suppressed IL-6 and significantly increased IL-10 on dpi 24 in INI-0602-treated mice, and significantly suppressed IFN-γ and MCP-1 on dpi 50 in the same group. In vitro INI-0602 treatment inhibited ATP-induced calcium propagations of Cx43+/+ astroglial cells to similar levels of those of Cx43-/- cells. Astroglial Cx43 hemichannels represent a novel therapeutic target for chronic EAE and MS.

Association between hypothalamic Alzheimer's disease pathology and body mass index: The Hisayama study.

The hypothalamus is the region of the brain that integrates the neuroendocrine system and whole-body metabolism. Patients with Alzheimer's disease (AD) have been reported to exhibit pathological changes in the hypothalamus, such as neurofibrillary tangles (NFTs) and amyloid plaques (APs). However, few studies have investigated whether hypothalamic AD pathology is associated with clinical factors. We investigated the association between AD-related pathological changes in the hypothalamus and clinical pictures using autopsied brain samples obtained from deceased residents of a Japanese community. A total of 85 autopsied brain samples were semi-quantitatively analyzed for AD pathology, including NFTs and APs. Our histopathological studies showed that several hypothalamic nuclei, such as the tuberomammillary nucleus (TBM) and lateral hypothalamic area (LHA), are vulnerable to AD pathologies. NFTs are observed in various neuropathological states, including normal cognitive cases, whereas APs are predominantly observed in AD. Regarding the association between hypothalamic AD pathologies and clinical factors, the degree of APs in the TBM and LHA was associated with a lower body mass index while alive, after adjusting for sex and age at death. However, we found no significant association between hypothalamic AD pathology and the prevalence of hypertension, diabetes, or dyslipidemia. Our study showed that a lower BMI, which is a poor prognostic factor of AD, might be associated with hypothalamic AP pathology and highlighted new insights regarding the disruption of the brain-whole body axis in AD.

A nationwide survey of facial onset sensory and motor neuronopathy in Japan.

The epidemiology and etiology of facial onset sensory and motor neuronopathy (FOSMN), a rare syndrome that initiates with facial sensory disturbances followed by bulbar symptoms, remain unknown. To estimate the prevalence of FOSMN in Japan and establish the characteristics of this disease, we conducted a nationwide epidemiological survey. In the primary survey, we received answers from 604 facilities (49.8%), leading to an estimated number of 35.8 (95% confidential interval: 21.5-50.2) FOSMN cases in Japan. The secondary survey collected detailed clinical and laboratory data from 21 cases. Decreased or absent corneal and pharyngeal reflexes were present in over 85% of the cases. Electrophysiological analyses detected blink reflex test abnormalities in 94.1% of the examined cases. Immunotherapy was administered in 81% of cases and all patients received intravenous immunoglobulin. Among them, 35.3% were judged to have temporary beneficial effects evaluated by the physicians in charge. Immunotherapy tended to be effective in the early stage of disease. The spreading pattern of motor and sensory symptoms differed between cases and the characteristics of the motor-dominant and sensory-dominant cases were distinct. Cases with motor-dominant progression appeared to mimic amyotrophic lateral sclerosis. This is the first nationwide epidemiological survey of FOSMN in Japan. The clinical course of FOSMN is highly variable and motor-dominant cases developed a more severe condition than other types of cases. Because clinical interventions tend to be effective in the early phase of the disease, an early diagnosis is desirable.

Progressive myoclonic epilepsy as an expanding phenotype of NGLY1-associated congenital deglycosylation disorder: A case report and review of the literature.

INTRODUCTION: NGLY1-associated congenital disorder of deglycosylation (CDDG1: OMIM #615273) is a rare autosomal recessive disorder caused by a functional impairment of endoplasmic reticulum in degradation of glycoproteins. Neurocognitive dysfunctions have been documented in patients with CDDG1; however, deteriorating phenotypes of affected individuals remain elusive. CASE PRESENTATION: A Japanese boy with delayed psychomotor development showed ataxic movements from age 5 years and myoclonic seizures from age 12 years. Appetite loss, motor and cognitive decline became evident at age 12 years. Electrophysiological studies identified paroxysmal discharges on myoclonic seizure and a giant somatosensory evoked potential. Perampanel was effective for controlling myoclonic seizures. Exome sequencing revealed that the patient carried compound heterozygous variants in NGLY1, NM_018297.4: c.857G > A and c.-17_12del, which were inherited from mother and father, respectively. A literature review confirmed that myoclonic seizures were observed in 28.5% of patients with epilepsy. No other patients had progressive myoclonic epilepsy or cognitive decline in association with loss-of-function variations in NGLY1. CONCLUSION: Our data provides evidence that a group of patients with CDDG1 manifest slowly progressive myoclonic epilepsy and cognitive decline during the long-term clinical course.

A case of monozygotic twins with hereditary spastic paraplegia type 4 and epilepsy, of whom only one developed narcolepsy type 1.

We report a case of monozygotic twin sisters with hereditary spastic paraplegia type 4 (SPG4) and epilepsy, only one of whom had a diagnosis of narcolepsy type 1 (NT1). The older sister with NT1 exhibited excessive daytime sleepiness, cataplexy, sleep-onset rapid eye movement period in the multiple sleep latency test, and decreased orexin levels in cerebrospinal fluid. Both sisters had HLA-DRB1*15:01-DQB1*06:02 and were further identified to have a novel missense mutation (c.1156A > C, p.Asn386His) in the coding exon of the spastin (SPAST) gene. The novel missense mutation might be involved in the development of epilepsy. This case is characterised by a combined diagnosis of SPG4 and epilepsy, and it is the first report of NT1 combined with epilepsy and genetically confirmed SPG4. The fact that only one of the twins has NT1 suggests that acquired and environmental factors are important in the pathogenesis of NT1.

[A case of very long chain acyl-CoA dehydrogenase deficiency diagnosed due to a trigger of hyperemesis gravidarum during pregnancy].

A 25-year-old Japanese woman with a history of repeated episodes of rhabdomyolysis since the age of 12 presented with rhabdomyolysis caused by hyperemesis gravidarum. Blood tests showed an elevated serum CK level (11,755 |IU/l; normal: 30-180 |IU/l). Carnitine fractionation analysis revealed low levels of total carnitine (18.3 |µmol/l; normal: 45-91 |µmol/l), free carnitine (13.1 |µmol/l; normal: 36-74 |µmol/l), and acylcarnitine (5.2 |µmol/l; normal: 6-23 |µmol/l). Tandem mass spectrometry showed high levels of C14:1 acylcarnitine (0.84 |nmol/ml: normal: <0.4 |nmol/ml) and a high C14:1/C2 ratio of 0.253 (normal: <0.013), indicating a potential diagnosis of very long-chain acyl-CoA dehydrogenase (VLCAD) deficiency. Enzyme activity measurement in the patient's peripheral blood lymphocytes confirmed the diagnosis of VLCAD deficiency, with low palmitoyl-CoA dehydrogenase levels (6.5% of normal control value). With the patient's informed consent, acyl-CoA dehydrogenase very long-chain (ACADVL) gene analysis revealed compound heterozygous mutations of c.1332G>A in exon 13 and c.1349G>A (p.R450H) in exon 14. In Japan, neonatal mass screening is performed to detect congenital metabolic diseases. With the introduction of tandem mass screening in 2014, fatty acid metabolism disorders, including VLCAD deficiency, are being detected before the onset of symptoms. However, it is important to note that mass screening cannot detect all cases of this disease. For patients with recurrent rhabdomyolysis, it is essential to consider congenital diseases, including fatty acid metabolism disorders, as a potential diagnosis.

Direct neuronal conversion of microglia/macrophages reinstates neurological function after stroke.

Although generating new neurons in the ischemic injured brain would be an ideal approach to replenish the lost neurons for repairing the damage, the adult mammalian brain retains only limited neurogenic capability. Here, we show that direct conversion of microglia/macrophages into neurons in the brain has great potential as a therapeutic strategy for ischemic brain injury. After transient middle cerebral artery occlusion in adult mice, microglia/macrophages converge at the lesion core of the striatum, where neuronal loss is prominent. Targeted expression of a neurogenic transcription factor, NeuroD1, in microglia/macrophages in the injured striatum enables their conversion into induced neuronal cells that functionally integrate into the existing neuronal circuits. Furthermore, NeuroD1-mediated induced neuronal cell generation significantly improves neurological function in the mouse stroke model, and ablation of these cells abolishes the gained functional recovery. Our findings thus demonstrate that neuronal conversion contributes directly to functional recovery after stroke.

Iguratimod Ameliorates the Severity of Secondary Progressive Multiple Sclerosis in Model Mice by Directly Inhibiting IL-6 Production and Th17 Cell Migration via Mitigation of Glial Inflammation.

We previously reported a novel secondary progressive multiple sclerosis (SPMS) model, progressive experimental autoimmune encephalomyelitis (pEAE), in oligodendroglia-specific Cx47-inducible conditional knockout (Cx47 icKO) mice. Based on our prior study showing the efficacy of iguratimod (IGU), an antirheumatic drug, for acute EAE treatment, we aimed to elucidate the effect of IGU on the SPMS animal model. We induced pEAE by immunizing Cx47 icKO mice with myelin oligodendrocyte glycoprotein peptide 35-55. IGU was orally administered from 17 to 50 days post-immunization. We also prepared a primary mixed glial cell culture and measured cytokine levels in the culture supernatant after stimulation with designated cytokines (IL-1α, C1q, TNF-α) and lipopolysaccharide. A migration assay was performed to evaluate the effect of IGU on the migration ability of T cells toward mixed glial cell cultures. IGU treatment ameliorated the clinical signs of pEAE, decreased the demyelinated area, and attenuated glial inflammation on immunohistochemical analysis. Additionally, IGU decreased the intrathecal IL-6 level and infiltrating Th17 cells. The migration assay revealed reduced Th17 cell migration and IL-6 levels in the culture supernatant after IGU treatment. Collectively, IGU successfully mitigated the clinical signs of pEAE by suppressing Th17 migration through inhibition of IL-6 production by proinflammatory-activated glial cells.

Caution to Poor Adherence With Immunosuppressant Medication That Causes Coma-Onset Autoimmune Encephalitis: A Case Report and Literature Review.

Autoimmune encephalitis after liver transplantation (LT) is a rare disorder. This is because patients are usually in an immunosuppressed state after LT. Here, we report a rare case of autoantibody-negative autoimmune-encephalitis-induced coma after living-donor (LD) LT. A 45-year-old woman who underwent LDLT for primary biliary cholangitis (PBC) was brought to our hospital with the chief complaint of cognitive deficiency and an episode of memory loss. Physical examination, laboratory tests, and cerebrospinal fluid analysis revealed no significant findings. However, diffusion-weighted magnetic resonance imaging showed hyperintensity in the bilateral hippocampus. No autoantibodies associated with autoimmune encephalitis were detected. The diagnosis of antibody-negative autoimmune encephalitis was made on the basis of low immunosuppressive drug levels in the blood (indicative of poor adherence) and the presence of PBC as the autoimmune disease. The patient regained consciousness after intravenous methylprednisolone pulse therapy and plasma exchange. This case highlights that when examining patients with impaired consciousness after LDLT, it is important to consider autoimmune encephalitis as a potential diagnosis.

[Neuromyelitis Optica Spectrum Disorders].

Neuromyelitis optica spectrum disorders (NMOSD) are inflammatory autoimmune disorders of the central nervous system, that primarily cause optic neuritis and myelitis. Aquaporin-4 (AQP4) antibody is the key in NMOSD pathophysiology, which causes astrocytopathy, demyelination, and neuropathy through complement activation and cell-mediated immunity. Currently, biopharmaceutical agents are introduced for preventing relapse with high efficacy, expected to reduce side effects derived from long-term steroid therapy, and improve patients' quality of life.

Granulocyte activation markers in cerebrospinal fluid differentiate acute neuromyelitis spectrum disorder from multiple sclerosis.

BACKGROUND: Granulocyte invasion into the brain is a pathoanatomical feature differentiating neuromyelitis optica spectrum disorder (NMOSD) from multiple sclerosis (MS). We aimed to determine whether granulocyte activation markers (GAM) in cerebrospinal fluid (CSF) can be used as a biomarker to distinguish NMOSD from MS, and whether levels associate with neurological impairment. METHODS: We quantified CSF levels of five GAM (neutrophil elastase, myeloperoxidase, neutrophil gelatinase-associated lipocalin, matrixmetalloproteinase-8, tissue inhibitor of metalloproteinase-1), as well as a set of inflammatory and tissue-destruction markers, known to be upregulated in NMOSD and MS (neurofilament light chain, glial fibrillary acidic protein, S100B, matrix metalloproteinase-9, intercellular adhesion molecule-1, vascular cellular adhesion molecule-1), in two cohorts of patients with mixed NMOSD and relapsing-remitting multiple sclerosis (RRMS). RESULTS: In acute NMOSD, GAM and adhesion molecules, but not the other markers, were higher than in RRMS and correlated with actual clinical disability scores. Peak GAM levels occurred at the onset of NMOSD attacks, while they were stably low in MS, allowing to differentiate the two diseases for ≤21 days from onset of clinical exacerbation. Composites of GAM provided area under the curve values of 0.90-0.98 (specificity of 0.76-1.0, sensitivity of 0.87-1.0) to differentiate NMOSD from MS, including all anti-aquaporin-4 protein (aAQP4)-antibody-negative patients who were untreated. CONCLUSIONS: GAM composites represent a novel biomarker to reliably differentiate NMOSD from MS, including in aAQP4- NMOSD. The association of GAM with the degree of concurrent neurological impairment provides evidence for their pathogenic role, in turn suggesting them as potential drug targets in acute NMOSD.

Lineage tracing identifies in vitro microglia-to-neuron conversion by NeuroD1 expression.

Neuronal regeneration to replenish lost neurons after injury is critical for brain repair. Microglia, brain-resident macrophages that have the propensity to accumulate at the site of injury, can be a potential source for replenishing lost neurons through fate conversion into neurons, induced by forced expression of neuronal lineage-specific transcription factors. However, it has not been strictly demonstrated that microglia, rather than central nervous system-associated macrophages, such as meningeal macrophages, convert into neurons. Here, we show that NeuroD1-transduced microglia can be successfully converted into neurons in vitro using lineage-mapping strategies. We also found that a chemical cocktail treatment further promoted NeuroD1-induced microglia-to-neuron conversion. NeuroD1 with loss-of-function mutation, on the other hand, failed to induce the neuronal conversion. Our results indicate that microglia are indeed reprogrammed into neurons by NeuroD1 with neurogenic transcriptional activity.

Long-lasting pain and somatosensory disturbances in children with myelin oligodendrocyte glycoprotein antibody-associated disease.

Myelin oligodendrocyte glycoprotein antibody (MOG-Ab) is an autoantibody associated with acquired demyelinating syndrome (ADS) in childhood and adults. The pathogenic roles of MOG-Ab and long-term outcomes of children with MOG-Ab-associated disease (MOGAD) remain elusive. We investigated the clinical features of children with ADS during follow-up in our institute. Clinical data were retrospectively analyzed using medical charts of patients managed in Kyushu University Hospital from January 1st, 2001, to March 31st, 2022. Participants were children of < 18 years of age when they received a diagnosis of ADS in our hospital. Cell-based assays were used to detect MOG-Ab in serum or cerebrospinal fluid at the onset or recurrence of ADS. The clinical and neuroimaging data of MOG-Ab-positive and MOG-Ab-negative patients were statistically analyzed. Among 31 patients enrolled in this study, 22 (13 females, 59%) received tests for MOG antibodies. Thirteen cases (59%) were MOG-Ab-positive and were therefore defined as MOGAD; 9 (41%) were MOG-Ab-negative. There were no differences between MOGAD and MOG-Ab-negative patients in age at onset, sex, diagnostic subcategories, or duration of follow-up. MOGAD patients experienced headache and/or somatosensory symptoms more frequently than MOG-Ab-negative patients (12/13 (92%) vs. 3/9 (22%); p = 0.0066). Somatosensory problems included persistent pain with hyperesthesia in the left toe, perineal dysesthesia, and facial hypesthesia. No specific neuroimaging findings were associated with MOGAD or the presence of somatosensory symptoms. CONCLUSIONS: Long-lasting somatosensory disturbances are prominent comorbidities in children with MOGAD. Prospective cohorts are required to identify molecular and immunogenetic profiles associated with somatosensory problems in MOGAD. WHAT IS KNOWN: • Recurrence of demyelinating events occurs in a group of children with myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD). WHAT IS NEW: • Long-lasting headache and somatosensory problems are frequent comorbidities with pediatric MOGAD. Pain and somatosensory problems may persist for more than 5 years. • Neuroimaging data do not indicate specific findings in children with somatic disturbances.

Effect of smoking on disease activity in multiple sclerosis patients treated with dimethyl fumarate or fingolimod.

BACKGROUND: In relapsing-remitting multiple sclerosis (RRMS), smoking is a known risk factor for disease susceptibility and disability progression. However, its impact on the efficacy of oral disease-modifying drugs (DMDs) is unclear. Therefore, we initiated a single-center, retrospective, observational study to investigate the relationship between smoking and disease activity in RRMS patients under oral DMDs. METHODS: We retrospectively enrolled RRMS patients who initiated oral DMDs (fingolimod or dimethyl fumarate) at our hospital between January 2012 and December 2019. Clinical data and smoking status at oral DMD initiation were collected up to December 2020. We conducted survival analyses for relapse and any disease activity, defined as relapse or MRI disease activity, among patients with distinct smoking statuses. RESULTS: We enrolled 103 RRMS patients under oral DMDs including 19 (18.4%) current smokers at baseline. Proportions of relapses and any disease activity during follow-up were higher in current smokers (relapse: p = 0.040, any disease activity: p = 0.004) and time from initiating oral DMDs to relapse was shorter in current smokers (log-rank test: p = 0.011; Cox proportional hazard analysis: hazard ratio (HR) 2.72 [95% confidence interval (CI) 1.22-6.09], p = 0.015) than in non-smokers. Time from initiating oral DMDs to any disease activity was also shorter in current smokers (log-rank test: p = 0.016; Cox proportional hazard analysis: HR 2.18 [95% CI 1.14-4.19], p = 0.019) than in non-smokers. The survival curves for relapse and any disease activity were not different between the former smoker and never-smoker groups. Multivariate survival analysis showed current smoking was an independent risk factor for relapse or any disease activity after adjusting for covariates (relapse: HR 2.54 [95% CI 1.06-6.10], p = 0.037; any disease activity: HR 3.47 [95% CI 1.27-9.50], p = 0.015). CONCLUSION: Smoking was a risk factor for disease activity in RRMS patients under oral DMD treatment. RRMS patients should be advised to stop smoking even after the initiation of DMDs.

Anti-LGI4 Antibody Is a Novel Juxtaparanodal Autoantibody for Chronic Inflammatory Demyelinating Polyneuropathy.

BACKGROUND AND OBJECTIVES: The objective of this study was to discover novel nodal autoantibodies in chronic inflammatory demyelinating polyneuropathy (CIDP). METHODS: We screened for autoantibodies that bind to mouse sciatic nerves and dorsal root ganglia (DRG) using indirect immunofluorescence (IFA) assays with sera from 113 patients with CIDP seronegative for anti-neurofascin 155 and anticontactin-1 antibodies and 127 controls. Western blotting, IFA assays using HEK293T cells transfected with relevant antigen expression plasmids, and cell-based RNA interference assays were used to identify target antigens. Krox20 and Periaxin expression, both of which independently control peripheral nerve myelination, was assessed by quantitative real-time PCR after application of patient and control sera to Schwann cells. RESULTS: Sera from 4 patients with CIDP, but not control sera, selectively bound to the nodal regions of sciatic nerves and DRG satellite glia (p = 0.048). The main immunoglobulin G (IgG) subtype was IgG4. IgG from these 4 patients stained a 60-kDa band on Western blots of mouse DRG and sciatic nerve lysates. These features indicated leucine-rich repeat LGI family member 4 (LGI4) as a candidate antigen. A commercial anti-LGI4 antibody and IgG from all 4 seropositive patients with CIDP showed the same immunostaining patterns of DRG and cultured rat Schwann cells and bound to the 60-kDa protein in Western blots of LGI4 overexpression lysates. IgG from 3 seropositive patients, but none from controls, bound to cells cotransfected with plasmids containing LGI4 and a disintegrin and metalloprotease domain-containing protein 22 (ADAM22), an LGI4 receptor. In cultured rat Schwann and human melanoma cells constitutively expressing LGI4, LGI4 siRNA effectively downregulated LGI4 and reduced patients' IgG binding compared with scrambled siRNA. Application of serum from a positive patient to Schwann cells expressing ADAM22 significantly reduced the expression of Krox20, but not Periaxin. Anti-LGI4 antibody-positive patients had a relatively old age at onset (mean age 58 years), motor weakness, deep and superficial sensory impairment with Romberg sign, and extremely high levels of CSF protein. Three patients showed subacute CIDP onset resembling Guillain-Barré syndrome. DISCUSSION: IgG4 anti-LGI4 antibodies are found in some elderly patients with CIDP who present subacute sensory impairment and motor weakness and are worth measuring, particularly in patients with symptoms resembling Guillain-Barré syndrome.

Early and extensive alterations of glial connexins, distal oligodendrogliopathy type demyelination, and nodal/paranodal pathology are characteristic of multiple system atrophy.

The pathological hallmark of multiple system atrophy (MSA) is aberrant accumulation of phosphorylated α-synuclein in oligodendrocytes, forming glial cytoplasmic inclusions (GCIs). Extensive demyelination occurs particularly in the olivopontocerebellar and striatonigral pathways, but its precise mechanism remains elusive. Glial connexins (Cxs), which form gap junction channels between astrocytes and oligodendrocytes, play critical roles in myelin maintenance, and have not been studied in MSA. Therefore, we immunohistochemically investigated glial Cx changes in the cerebellar afferent fibers in 15 autopsied patients with MSA. We classified demyelinating lesions into three stages based on Klüver-Barrera staining: early (Stage I), intermediate (Stage II), and late (Stage III) stages showing subtle, moderate, and severe myelin reduction, respectively. Myelin-associated glycoprotein, but not myelin oligodendrocyte glycoprotein, was preferentially decreased in Stage I, suggesting distal oligodendrogliopathy type demyelination. Accumulation of phosphorylated α-synuclein in oligodendrocytes was frequently seen in Stage I but less frequently observed in Stages II and III. Tubulin polymerization-promoting protein (TPPP/p25α)-positive oligodendrocytes were preserved in Stage I but successively decreased in Stages II and III. Even at Stage I, Cx32 was nearly absent from myelin, despite the relative preservation of other nodal proteins, such as neurofascin, claudin-11/oligodendrocyte-specific protein, and contactin-associated protein 1, which successively decreased in the later stages. Cx32 was re-distributed in the oligodendrocyte cytoplasm and co-localized with GCIs. Cx47 gradually decreased at the oligodendrocyte surface in a stage-dependent manner but was not co-localized with GCIs. Astrocytic Cx43 was down-regulated in Stage I but up-regulated in Stages II and III, reflecting astrogliosis. Cx43/Cx47 gap junctions significantly decreased from Stage I to III. Activated microglia/macrophages and T cells infiltrated in Stage I rather than Stages II and III. Therefore, early and extensive alterations of glial Cxs, particularly Cx32 loss, occur in MSA and may accelerate distal oligodendrogliopathy type demyelination and nodal/paranodal dysfunction through disruption of inter-glial communication.

Demyelinating Neuropathy with Markedly Elevated Serum IgG4 Levels and Anti-Contactin 1 IgG4 Antibody.

We herein report a 77-year-old man with a 4-month history of progressive gait and sensory disturbances of the extremities. A nerve conduction study indicated demyelinating polyneuropathy. Serum IgG4 levels and anti-contactin 1 IgG4 antibodies were markedly increased. The sural nerve biopsy specimen showed IgG4-positive plasma cell infiltration in the epineurium. Treatment with steroids resulted in an amelioration of functional status, improvement of nerve conduction parameters, decreased serum IgG4 levels, and negative conversion of anti-contactin 1 antibody. Further studies are needed to clarify the significance of IgG4-positive plasma cell infiltration in anti-contactin 1 antibody-positive neuropathies.

Polygenic risk score association with multiple sclerosis susceptibility and phenotype in Europeans.

Polygenic inheritance plays a pivotal role in driving multiple sclerosis susceptibility, an inflammatory demyelinating disease of the CNS. We developed polygenic risk scores (PRS) of multiple sclerosis and assessed associations with both disease status and severity in cohorts of European descent. The largest genome-wide association dataset for multiple sclerosis to date (n = 41 505) was leveraged to generate PRS scores, serving as an informative susceptibility marker, tested in two independent datasets, UK Biobank [area under the curve (AUC) = 0.73, 95% confidence interval (CI): 0.72-0.74, P = 6.41 × 10-146] and Kaiser Permanente in Northern California (KPNC, AUC = 0.8, 95% CI: 0.76-0.82, P = 1.5 × 10-53). Individuals within the top 10% of PRS were at higher than 5-fold increased risk in UK Biobank (95% CI: 4.7-6, P = 2.8 × 10-45) and 15-fold higher risk in KPNC (95% CI: 10.4-24, P = 3.7 × 10-11), relative to the median decile. The cumulative absolute risk of developing multiple sclerosis from age 20 onwards was significantly higher in genetically predisposed individuals according to PRS. Furthermore, inclusion of PRS in clinical risk models increased the risk discrimination by 13% to 26% over models based only on conventional risk factors in UK Biobank and KPNC, respectively. Stratifying disease risk by gene sets representative of curated cellular signalling cascades, nominated promising genetic candidate programmes for functional characterization. These pathways include inflammatory signalling mediation, response to viral infection, oxidative damage, RNA polymerase transcription, and epigenetic regulation of gene expression to be among significant contributors to multiple sclerosis susceptibility. This study also indicates that PRS is a useful measure for estimating susceptibility within related individuals in multicase families. We show a significant association of genetic predisposition with thalamic atrophy within 10 years of disease progression in the UCSF-EPIC cohort (P < 0.001), consistent with a partial overlap between the genetics of susceptibility and end-organ tissue injury. Mendelian randomization analysis suggested an effect of multiple sclerosis susceptibility on thalamic volume, which was further indicated to be through horizontal pleiotropy rather than a causal effect. In summary, this study indicates important, replicable associations of PRS with enhanced risk assessment and radiographic outcomes of tissue injury, potentially informing targeted screening and prevention strategies.