Overlapping syndrome of recurrent anti-N-methyl-D-aspartate receptor encephalitis and anti-myelin oligodendrocyte glycoprotein demyelinating diseases:A case report

BACKGROUND Anti-N-methyl-D-aspartate receptor encephalitis(NMDARe)is capable of presenting a relapsing course and coexisting with myelin oligodendrocyte glycoprotein antibody disease,whereas it has been relatively rare.We describe a man with no history of tumor who successively developed anti-NMDARe and anti-myelin oligodendrocyte glycoprotein antibody disease.CASE SUMMARY A 29-year-old man was initially admitted with headache,fever,intermittent abnormal behavior,decreased intelligence,limb twitching and loss of consciousness on July 16,2018.On admission,examination reported no abnormality.During his presentation,he experienced aggravated symptoms,and the reexamination of cranial magnetic resonance imaging(MRI)indicated punctate abnormal signals in the left parietal lobe.External examination of cerebrospinal fluid and serum results revealed serum NMDAR antibody(Ab)(-),cerebrospinal fluid NMDAR-Ab(+)1:10 and Epstein-Barr virus capsid antigen antibody Ig G(+).Due to the imaging findings,anti-NMDARe was our primary consideration.The patient was treated with methylprednisolone and gamma globulin pulse therapy,mannitol injection dehydration to reduce intracranial pressure,sodium valproate sustained-release tablets for anti-epilepsy and olanzapine and risperidone to mitigate psychiatric symptoms.The patient was admitted to the hospital for the second time for“abnormal mental behavior and increased limb movements”on December 14,2018.Re-examination of electroencephalography and cranial MRI showed no abnormality.The results of autoimmune encephalitis antibody revealed that serum NMDAR-Ab was weakly positive and cerebrospinal fluid NMDAR-Ab was positive.Considering comprehensive recurrent anti-NMDARe,the patient was treated with propylene-hormone pulse combined with immunosuppressive agents(mycophenolate mofetil),and the symptoms were relieved.The patient was admitted for“hoarseness and double vision”for the third time on August 23,2019.Re-examination of cranial MRI showed abnormal signals in the medulla oblongata and right frontal lobe,and synoptophore examination indicated concomitant esotropia.The patient’s visual acuity further decreased,and the reexamination of cranial MRI+enhancement reported multiple scattered speckled and patchy abnormal signals in the medulla oblongata,left pons arm,left cerebellum and right midbrain,thalamus.The patient was diagnosed with an accompanying demyelinating disease.Serum antimyelin oligodendrocyte glycoprotein 1:10 and NMDAR antibody 1:10 were both positive.The patient was diagnosed with myelin oligodendrocyte glycoprotein antibody-related inflammatory demyelinating disease of the central nervous system complicated with anti-NMDARe overlap syndrome.The patient was successfully treated with methylprednisolone,gamma globulin pulse therapy and rituximab treatment.The patient remained asymptomatic and follow-up MRI scan 6 mo later showed complete removal of the lesion.CONCLUSION We emphasize the rarity of this antibody combination and suggest that these patients may require longer follow-up due to the risk of recurrence of two autoimmune disorders.

Neuromyelitis optica and myelin oligodendrocyte glycoprotein

Neuromyelitis optica(NMO)refers to an antibody mediated,inflammatory disorder of the central nervous system(CNS)characterized by recurrent or monophasic attacks of optic neuritis and myelitis.Most patients with NMO possess a specific serum immunoglobin,NMO-IgG,which can serve as a biomarker for NMO.The autoantibodies target aquaporin-4(AQP4),the main water channel protein found in the CNS including the brain,spinal cord,and optic nerve.The remaining 10-25%of patients are seronegative for NMO-IgG despite meeting the diagnostic criteria for NMO.Recent studies have shown that a subset of these patients is seropositive for antibodies against myelin oligodendrocyte glycoprotein(MOG).This paper will provide an overview of the current English scientific literature published regarding the history,epidemiology,AQP4 biomarker,MOG biomarker,diagnosis,clinical features,related diseases in NMO spectrum disorder(NMOSD),and treatments of NMO.

Biomarkers for neuromyelitis optica:a visual analysis of emerging research trends

Neuromyelitis optica is an inflammatory demyelinating disease of the central nervous system that differs from multiple sclerosis.Over the past 20 years,the search for biomarke rs for neuromyelitis optica has been ongoing.Here,we used a bibliometric approach to analyze the main research focus in the field of biomarkers for neuromyelitis optica.Research in this area is consistently increasing,with China and the United States leading the way on the number of studies conducted.The Mayo Clinic is a highly reputable institution in the United States,and was identified as the most authoritative institution in this field.Furthermore,Professor Wingerchuk from the Mayo Clinic was the most authoritative expe rt in this field.Keyword analysis revealed that the terms "neuro myelitis optica"(261 times), "multiple sclerosis"(220 times), "neuromyelitis optica spectrum disorder"(132 times), "aquaporin4"(99 times),and "optical neuritis"(87 times) were the most frequently used keywords in literature related to this field.Comprehensive analysis of the classical literature showed that the majority of publications provide conclusive research evidence supporting the use of aquaporin-4-IgG and neuromyelitis optica-IgG to effectively diagnose and differentiate neuromyelitis optica from multiple sclerosis.Furthermore,aquaporin-4-IgG has emerged as a highly specific diagnostic biomarker for neuromyelitis optica spectrum disorder.Myelin oligodendrocyte glycoprotein-IgG is a diagnostic biomarke r for myelin oligodendrocyte glycoprotein antibody-associated disease.Recent biomarkers for neuromyelitis optica in clude cerebrospinal fluid immunological biomarkers such as glial fibrillary acidic protein,serum astrocyte damage biomarkers like FAM19A5,serum albumin,and gammaaminobutyric acid.The latest prospective clinical trials are exploring the potential of these biomarkers.Preliminary results indicate that glial fibrillary acidic protein is emerging as a promising candidate biomarker for neuromyelitis optica spectrum disorder.The ultimate goal of future research is to identify non-invasive biomarkers with high sensitivity,specificity,and safety for the accurate diagnosis of neuro myelitis optica.

Comparison of macular changes according to the etiology of optic neuritis:a cross-sectional study

AIM:To compare the macular structure including foveal thickness among patients with optic neuritis(ON)according to the etiology and to investigate the possible correlation between structural and visual outcomes METHODS:In this retrospective cross-sectional study,the clinical data of patients with aquaporin-4 immunoglobulin G-related ON(AQP4 group,40 eyes),myelin oligodendrocyte glycoprotein IgG-related ON(MOG group,31 eyes),and multiple sclerosis-related ON(MS group,24 eyes)were obtained.The retinal thickness of the foveal,parafoveal and perifoveal regions were measured.Visual acuity(VA),visual field index and mean deviation were measured as visual outcomes.RESULTS:The AQP4 group showed a significantly thinner fovea(226.4±13.4μm)relative to the MOG(236.8±14.0μm,P=0.015)and MS(238.9±14.3μm,P=0.007)groups.The thickness in the parafoveal area also was thinner in the AQP4 group,though the difference in perifoveal retinal thickness was not significant.Foveal thickness was correlated with VA in the AQP4 group(coefficientρ=-0.418,P=0.014),but not in the MOG and MS groups(P=0.218 and P=0.138,respectively).There was no significant correlation between foveal thickness and visual field test in all three groups.CONCLUSION:The significant thinning in the fovea and parafoveal areas in the AQP4 group compared to the MOG and MS groups are found.Additionally,macular changes in AQP4-ON show a significant correlation with VA.The results provide the possibility that retinal structural damage could reflect functional damage in AQP4-ON,distinct from MOGON and MS-ON.

Axonal growth inhibitors and their receptors in spinal cord injury:from biology to clinical translation

Axonal growth inhibitors are released during traumatic injuries to the adult mammalian central nervous system, including after spinal cord injury. These molecules accumulate at the injury site and form a highly inhibitory environment for axonal regeneration. Among these inhibitory molecules, myelinassociated inhibitors, including neurite outgrowth inhibitor A, oligodendrocyte myelin glycoprotein, myelin-associated glycoprotein, chondroitin sulfate proteoglycans and repulsive guidance molecule A are of particular importance. Due to their inhibitory nature, they represent exciting molecular targets to study axonal inhibition and regeneration after central injuries. These molecules are mainly produced by neurons, oligodendrocytes, and astrocytes within the scar and in its immediate vicinity. They exert their effects by binding to specific receptors, localized in the membranes of neurons. Receptors for these inhibitory cues include Nogo receptor 1, leucine-rich repeat, and Ig domain containing 1 and p75 neurotrophin receptor/tumor necrosis factor receptor superfamily member 19(that form a receptor complex that binds all myelin-associated inhibitors), and also paired immunoglobulin-like receptor B. Chondroitin sulfate proteoglycans and repulsive guidance molecule A bind to Nogo receptor 1, Nogo receptor 3, receptor protein tyrosine phosphatase σ and leucocyte common antigen related phosphatase, and neogenin, respectively. Once activated, these receptors initiate downstream signaling pathways, the most common amongst them being the Rho A/ROCK signaling pathway. These signaling cascades result in actin depolymerization, neurite outgrowth inhibition, and failure to regenerate after spinal cord injury. Currently, there are no approved pharmacological treatments to overcome spinal cord injuries other than physical rehabilitation and management of the array of symptoms brought on by spinal cord injuries. However, several novel therapies aiming to modulate these inhibitory proteins and/or their receptors are under investigation in ongoing clinical trials. Investigation has also been demonstrating that combinatorial therapies of growth inhibitors with other therapies, such as growth factors or stem-cell therapies, produce stronger results and their potential application in the clinics opens new venues in spinal cord injury treatment.

Neurofilament light chain in demyelinating conditions of the central nervous system: a promising biomarker

Neurofilaments are the major structural proteins of the neuronal cytoskeleton and are classified according to molecular weight into heavy,intermediate,and light chains.They are released into the interstitial fluid and cerebrospinal fluid(CSF)as a consequence of axonal damage.In particular,the light chain(NfL)represents the most abundant and soluble subunit and has been demonstrated to be increased in the CSF of patients with inflammatory,degenerative,vascular,or traumatic injuries in correlation with clinical and radiological activity.Similar results have been obtained measuring serum NfL with high-sensitivity single-molecule array,which enables reliable and repeatable measurement of the low NfL concentrations in serum.In particular,CSF and serum NfL values are strongly correlated in patients with multiple sclerosis(MS)and have been demonstrated to be increased in patients with MS and clinically isolated syndromes(CIS)in accordance with clinical and radiological activity.NfL levels increase in patients with a recent relapse and seem to predict cognitive impairment,long-term outcome,and conversion of CIS to MS.The few available data on patients with other demyelinating diseases suggest that NfL levels are also increased in neuromyelitis optica spectrum disorders and related conditions in correlation with attack severity,suggesting that axonal damage may occur in these disorders.We herein report and discuss published data on the role of NfL as a possible predictor of disease activity,clinical outcome and treatment response in patients with demyelinating conditions of the central nervous system.

MiR-125a-5p Regulates Vitamin D Receptor Expression in a Mouse Model of Experimental Autoimmune Encephalomyelitis

Multiple sclerosis(MS)is a chronic and incurable autoimmune neurodegenerative disease of the central nervous system.Although the symptoms of MS can be managed by vitamin D3 treatment alone,this condition cannot be completely eradicated.Thus,there might be unknown factors capable of regulating the vitamin D receptor(VDR).Genome-wide analysis showed that miRNAs were associated with VDRs.We sought to determine the role and mechanism of action of miRNA-125a-5p and VDRs in a model of MS,mice with experimental autoimmune encephalomyelitis(EAE),which was induced by myelin oligodendrocyte glycoprotein 35–55 peptides.EAE mice showed decreased mean body weight but increased mean clinical scores compared with vehicle or control mice.And inflammatory infiltration was found in the lumbosacral spinal cord of EAE mice.In addition,VDR expression was significantly lower while the expression of miR-125a-5p was markedly higher in the spinal ventral horn of EAE mice than in vehicle or control mice.Importantly,activation of VDRs by paricalcitol or inhibition of miR-125a-5p by its antagomir markedly decreased the mean clinical scores in EAE mice.Interestingly,VDR and miR-125a-5p were co-localized in the same neurons of the ventral horn.More importantly,inhibition of miR-125a-5p remarkably blocked the decrease of VDRs in EAE mice.These results support a critical role for miR-125a-5p in modulating VDR activity in EAE and suggest potential novel therapeutic interventions.