NMOSD acute attack: Understanding, treatment and innovative treatment prospect

Clinical efficacy of efgartigimod combined with intravenous methylprednisolone in the acute phase of neuromyelitis optica spectrum disorders

BACKGROUND

Neuromyelitis Optica Spectrum Disorders (NMOSD) comprise a group of autoimmune-mediated, inflammatory, demyelinating central nervous system diseases caused by aquaporin-4 (AQP4) IgG autoantibodies. Efgartigimod is a human IgG Fc fragment that reduces antibody titers by targeting the neonatal Fc receptor (FcRn). This study documents the efficacy of efgartigimod combined with intravenous methylprednisolone (IVMP) in the acute phase of NMOSD.

METHODS

In this retrospective study, the medical records of NMOSD patients with acute attack who received efgartigimod plus IVMP or IVMP were reviewed. Treatment efficacy was assessed by the Expanded Disability Scale Score (EDSS) before and one month after treatment. Any side effects that occurred during the treatment period were recorded.

RESULTS

This study was performed on 11 patients (efgartigimod plus IVMP group [n = 4] and IVMP group [n = 7]). Efgartigimod plus IVMP was effective and had a satisfactory safety profile. EDSS was reduced by 0.5 ± 0.32 compared with the IVMP group (0.27 ± 0.02). Immunoglobulin was decreased in three patients, and the immunoglobulin G (IgG) levels gradually increased approximately 8 weeks after the last administration. Hyperlipidemia and elevated white blood cell count were common side effects. No infections or deaths occurred.

CONCLUSIONS

Efgartigimod plus IVMP treatment is safe and well-tolerated in patients with acute-phase NMOSD.

Preliminary findings of a 'test bundle' to accelerate the diagnosis of MS and NMOSD following optic neuritis

No study has investigated the length of time it takes to diagnose multiple sclerosis (MS) or neuromyelitis optic spectrum disorder (NMOSD, aquaporin 4 antibody disease or myelin oligodendrocyte glycoprotein antibody disease, MOGAD) following the onset of de novo optic neuritis (ON). Minimizing the time between ON and downstream diagnoses needs urgency since early diagnosis equals early treatment. The time elapsed from ON to a subsequent diagnosis of MS/NMOSD was estimated through analysis of retrospective data collected from the Axon Registry (AR) of the American Academy of Neurology (AAN) and from the University of Kentucky (UK), Lexington. The time to diagnose MS/NMOSD was arbitrarily set as occurring < 6 months (early) or > 6 months (delayed) following ON. Data was collected between 2007 and 2021 (AR) and 2012 to 2022, for UK, respectively. Of the 4015 ON patients from the AR dataset, 1069 (26.6 %) were diagnosed with MS, with 857 (80.2 %) diagnosed < 6 months (early) and 212 (19.8 %) diagnosed after > 6 months (delayed). Secondly, 420/4015 (10.4 %) were diagnosed with NMOSD (either MOGAD or AQP4 antibody disease), of which 340/420 (80.9 %) were diagnosed < 6 months (early) and 80/420 (19 %) diagnosed > 6 months (delayed). In the UK dataset, a total of 90/1464 individuals (6.14 %) were diagnosed with MS; of these, 69 patients (76.7 %) were diagnosed at < 6 months (early) and included a sub-group of 25 (27.8 %) diagnosed < 4 weeks; 21 (23.3 %) were diagnosed > 6 months (delayed) following ON. In either dataset (AR or UK, between 20 % - 23 % of MS diagnoses occurred > 6 months (delayed) after a diagnosis of ON. An accelerated diagnosis (4 weeks or less) of MS/NMOSD following ON in the UK data suggests that it is possible to minimize the time to a downstream diagnosis if a 'test bundle' of MRI of orbits, brain, C-spine, cerebrospinal fluid (CSF) analysis, and serum testing for NMOSD is used. Additional studies using prospective, larger datasets are required to confirm our findings.

Astrocyte-secreted C3 signaling impairs neuronal development and cognition in autoimmune diseases

Neuromyelitis optica (NMO) arises from primary astrocytopathy induced by autoantibodies targeting the astroglial protein aquaporin 4 (AQP4), leading to severe neurological sequelae such as vision loss, motor deficits, and cognitive decline. Mounting evidence has shown that dysregulated activation of complement components contributes to NMO pathogenesis. Complement C3 deficiency has been shown to protect against hippocampal neurodegeneration and cognitive decline in neurodegenerative disorders (e.g., Alzheimer's disease, AD) and autoimmune diseases (e.g., multiple sclerosis, MS). However, whether inhibiting the C3 signaling can ameliorate cognitive dysfunctions in NMO remains unclear. In this study, we found that the levels of C3a, a split product of C3, significantly correlate with cognitive impairment in our patient cohort. In response to the stimulation of AQP4 autoantibodies, astrocytes were activated to secrete complement C3, which inhibited the development of cultured neuronal dendritic arborization. NMO mouse models exhibited reduced adult hippocampal newborn neuronal dendritic and spine development, as well as impaired learning and memory functions, which could be rescued by decreasing C3 levels in astrocytes. Mechanistically, we found that C3a engaged with C3aR to impair neuronal development by dampening β-catenin signalling. Additionally, inhibition of the C3-C3aR-GSK3β/β-catenin cascade restored neuronal development and ameliorated cognitive impairments. Collectively, our results suggest a pivotal role of the activation of the C3-C3aR network in neuronal development and cognition through mediating astrocyte and adult-born neuron communication, which represents a potential therapeutic target for autoimmune-related cognitive impairment diseases.

Correlation between severe attacks and serum aquaporin-4 antibody titer in neuromyelitis optica spectrum disorder

Aquaporin 4-immunoglobulin G (AQP4-IgG) specifically targets aquaporin 4 in approximately 80% of Neuromyelitis Optica Spectrum Disorder (NMOSD) cases. NMOSD is presently categorized as anti-AQP4-antibody (Ab) positive or negative based on AQP4-Ab presence. The association between antibody titers and patient prognosis remains unclear. Therefore, the present study explores the correlation between severe attacks and serum AQP4 Ab titers in patients with neuromyelitis optica spectrum disorder. Data were gathered retrospectively from 546 patients with NMOSD between September 1, 2009, and December 1, 2021. Patients were categorized based on their AQP4-Ab titers: AQP4 titer ≥ 1:320 were classified as the high-titer group, AQP4 (+ +), and AQP4 titer of ≤ 1:100 were classified as the low-titer group, AQP4 ( +). Clinical characteristics and prognoses between the two groups were compared. Patients with AQP4 ( +) exhibited few severe optic neuritis (SON) attacks (false discovery rate [FDR] corrected p < 0.001), a reduced percentage experiencing SON attacks, and a lower incidence of visual disability than patients with AQP4 (+ +). Patients with AQP4 (+ +) and AQP4 ( +) NMOSD exhibited significant difference in annual recurrence rate (ARR) (FDR-corrected p < 0.001). The lower AQP4 Ab titer group demonstrated reduced susceptibility to severe relapse with conventional immunosuppressive agents and rituximab (RTX) than the higher titer group. No significant differences in sex, age at onset, coexisting connective tissue diseases, motor disability, or mortality rates were observed between the two groups. Higher AQP4 Ab titers correlated with increased disease severity and visual disability in patients with NMOSD.

GV-971 attenuates the progression of neuromyelitis optica in murine models and reverses alterations in gut microbiota and associated peripheral abnormalities

AIMS

Growing evidence suggests that an imbalanced gut microbiota composition plays a crucial role in the development of neuromyelitis optica spectrum disorders (NMOSD), an inflammatory demyelinating disease primarily affecting the optic nerves and central nervous system (CNS). In light of this, we explored the potential therapeutic benefits of GV-971 in NMOSD. GV-971 is a drug used for treating mild-to-moderate Alzheimer's disease, which targets the gut-brain axis and reduces neuroinflammation.

METHODS

To evaluate GV-971's effects, we employed the experimental autoimmune encephalomyelitis (EAE) mouse model to establish NMOSD animal models. This was achieved by injecting NMO-IgG into aged mice (11 months old) or using NMO-IgG along with complement injection and microbubble-enhanced low-frequency ultrasound (MELFUS) techniques in young mice (7 weeks old). We assessed the impact of GV-971 on incidence rate, clinical scores, body weight, and survival, with methylprednisolone serving as a positive control. In NMOSD models of young mice, we analyzed spinal cord samples through H&E staining, immunohistochemistry, and Luxol Fast Blue staining. Fecal samples collected at different time points underwent 16S rRNA gene sequencing, while plasma samples were analyzed using cytokine array and untargeted metabolomics analysis.

RESULTS

Our findings indicated that GV-971 significantly reduced the incidence of NMOSD, alleviated symptoms, and prolonged survival in NMOSD mouse models. The NMOSD model exhibited substantial neuroinflammation and injury, accompanied by imbalances in gut microbiota, peripheral inflammation, and metabolic disorders, suggesting a potentially vicious cycle that accelerates disease pathogenesis. Notably, GV-971 effectively reduces neuroinflammation and injury, and restores gut microbiota composition, as well as ameliorates peripheral inflammation and metabolic disorders.

CONCLUSIONS

GV-971 attenuates the progression of NMOSD in murine models and reduces neuroinflammation and injury, likely through its effects on remodeling gut microbiota and peripheral inflammation and metabolic disorders.

FcRn Inhibitor Therapies in Neurologic Diseases

In the last decade, the landscape of treating autoimmune diseases has evolved with the emergence and approval of novel targeted therapies. Several new biological agents offer selective and target-specific immunotherapy and therefore fewer side effects, such as neonatal Fc receptor (FcRn)-targeting therapy. Neonatal Fc receptor-targeted therapies are engineered to selectively target FcRn through various methods, such as Fc fragments or monoclonal anti-FcRn antibodies. These approaches enhance the breakdown of autoantibodies by blocking the immunoglobulin G recycling pathway. This mechanism reduces overall plasma immunoglobulin levels, including the levels of pathogenic autoantibodies, without affecting the other immunoglobulin class immunoglobulin A, immunoglobulin E, immunoglobulin M, and immunoglobulin D levels. Drugs that inhibit FcRn include efgartigimod, rozanolixizumab, batoclimab, and nipocalimab. These medications can be administered either intravenously or subcutaneously. Numerous clinical trials are currently underway to investigate their effectiveness, safety, and tolerability in various neurological conditions, including myasthenia gravis and other neurological disorders such as chronic inflammatory demyelinating polyneuropathy, myositis, neuromyelitis optica, and myelin oligodendrocyte glycoprotein antibody disease. Positive results from clinical trials of efgartigimod and rozanolixizumab led to their approval for the treatment of generalized myasthenia gravis. Additional clinical trials are still ongoing. Neonatal Fc receptor inhibitor agents seem to be well tolerated. Reported adverse events include headache (most commonly observed with efgartigimod and rozanolixizumab), upper respiratory tract infection, urinary tract infection, diarrhea, pyrexia, and nausea. Additionally, some of these agents may cause transient hypoalbuminemia and hypercholesterolemia notably reported with batoclimab and nipocalimab. In this review, we discuss the available clinical data for FcRN inhibitor agents in treating different neurological autoimmune diseases.

Early rituximab treatment reduces long-term disability in aquaporin-4 antibody-positive neuromyelitis optica spectrum

BACKGROUND

Neuromyelitis optica spectrum disorder (NMOSD) causes relapsing inflammatory attacks in the central nervous system, leading to disability. As rituximab, a B-lymphocyte-depleting monoclonal antibody, is an effective in preventing NMOSD relapses, we hypothesised that earlier initiation of rituximab can also reduce long-term disability of patients with NMOSD.

METHODS

This multicentre retrospective study involving 19 South Korean referral centres included patients with NMOSD with aquaporin-4 antibodies receiving rituximab treatment. Factors associated with the long-term Expanded Disability Status Scale (EDSS) were assessed using multivariable regression analysis.

RESULTS

In total, 145 patients with rituximab treatment (mean age of onset, 39.5 years; 88.3% female; 98.6% on immunosuppressants/oral steroids before rituximab treatment; mean disease duration of 121 months) were included. Multivariable analysis revealed that the EDSS at the last follow-up was associated with time to rituximab initiation (interval from first symptom onset to initiation of rituximab treatment). EDSS at the last follow-up was also associated with maximum EDSS before rituximab treatment. In subgroup analysis, the time to initiation of rituximab was associated with EDSS at last follow-up in patients aged less than 50 years, female and those with a maximum EDSS score ≥6 before rituximab treatment.

CONCLUSIONS

Earlier initiation of rituximab treatment may prevent long-term disability worsening in patients with NMOSD, especially among those with early to middle-age onset, female sex and severe attacks.

Prevalence of neuromyelitis optica spectrum disorder in Colombia: Analysis of the official Ministry of Health administrative registry

BACKGROUND

Neuromyelitis optica spectrum disorder (NMOSD) is a rare entity with severe inflammatory demyelinating events of the central nervous system with debilitating sequelae. Its global prevalence ranges between 0.5 and 4/100,000 individuals, with variations by region and ethnicity. Latin America lacks epidemiological data on the disease, and Colombian prevalence is unknown.

OBJECTIVE

Prevalence of NMOSD in Colombia was estimated between 2017 and 2021 using the official Ministry of Health administrative database (SISPRO).

METHODS

This is an observational, cross-sectional retrospective study, using data between January 2017 and December 2021 in the SISPRO database using the International Classification of Disease code for NMOSD G36.0. Prevalence by gender, age and geographic distribution was estimated using official government statistics for 2019. World Health Organization (WHO) standard population was used to adjust using the direct method.

RESULTS

2,650 patients were diagnosed with NMOSD; the average age was 44.9 years with an overall unadjusted prevalence of 5.3/100,000 individuals, higher for females (7.8) than for males (2.8). No significant changes (from 5.3 to 5.4) were seen after adjusting to the WHO standard.

CONCLUSION

According to this study Colombia has one of the highest prevalence rates of NMOSD in Latin America, further studies are needed to elucidate the contributing factors.

Breast cancer-associated paraneoplastic neuromyelitis optica with cervical cord compression and spondylosis requiring laminectomy: A case report

Neuromyelitis optica, an autoimmune inflammatory disorder affecting the central nervous system, can occur in a paraneoplastic context, although rare. We report an intriguing case of a 71-year-old woman with a history of triple-negative infiltrating ductal breast carcinoma, manifesting with paraneoplastic neuromyelitis optica that led to significant respiratory failure and required a cervical laminectomy. The patient presented with pain in the left breast, weakness in the lower extremities, and neck pain. The neurological evaluation showed 2/5 muscle strength in all extremities, diffuse hyperreflexia, and loss of multimodal sensation below the shoulder. She developed acute respiratory failure that required mechanical ventilation. Magnetic resonance imaging highlighted a diffuse abnormal increase in T2 signal intensity throughout the posterior and central portion of the cervical and thoracic spinal cord consistent with longitudinally extensive transverse myelitis, and significant cervical cord compression at C3-C4. Magnetic resonance imaging of the brain showed non-enhancing T2/fluid-attenuated inversion recovery (FLAIR) white matter hyperintensities and cerebellar hemispheres. The serum cell-based assay study demonstrated a high anti-aquaporin-4 immunoglobulin G titer (>1:160) confirming the diagnosis of neuromyelitis optica. She was taken for bilateral laminectomy from C3 to C6. Despite intravenous methylprednisolone and plasmapheresis treatment, no significant recovery was achieved, necessitating tracheostomy and percutaneous endoscopic gastrostomy. Subsequent rituximab treatment led to a mild improvement, with no new lesions on repeat magnetic resonance imaging. This case raises suspicion of the potential for neuromyelitis optica to occur as a paraneoplastic phenomenon, strengthening the need for vigilance in patients with malignancies.

High-efficacy therapies reduce clinical and radiological events more effectively than traditional treatments in neuromyelitis optica spectrum disorder

BACKGROUND

People with neuromyelitis optica spectrum disorder (pwNMOSD) experience debilitating neurological attacks, resulting in permanent disability.

OBJECTIVE

To evaluate if high-efficacy treatment was better than traditional agents at preventing disease advancement in pwNMOSD.

METHODS

A retrospective study of pwNMOSD at one academic center was performed. Timelines were created for treatments subjects were exposed to along with clinical/radiological events related to disease worsening. High-efficacy treatments included eculizumab, inebilizumab, satralizumab, rituximab, ocrelizumab, tocilizumab, and sarilumab while therapies such as azathioprine, methotrexate, cyclophosphamide, and mycophenolate mofetil were classified as traditional agents. Poisson regression and mixed effects logistics models were constructed, and a subject-specific random intercept was used for intrasubject correlation.

RESULTS

Of 189 pwNMOSD identified, 161 were aquaporin-4 IgG positive (AQP4 +) with 92 (77 female; median disease duration (MDD) (range) of 6.6 years (y) (1.2-18.6)) exposed only to high-efficacy therapy, 33 (28 female; 10.4 y (0.8-32.7)) only to traditional therapy, and 64 (54 female; 10.8 y (0.7-20.2)) to both. High-efficacy treatments reduced the rate of MRI advancement by 62.4% (95% CrI = [- 86.9%, - 16.8%]), relapses by 99.8% (95% CrI = [- 99.9%, - 99.6%]), and hospitalizations by 99.3% (95% CrI = [- 99.6%, - 98.8%]) when compared to traditional treatments. For AQP4 + subjects, a 655.7-fold increase in the odds of new spinal cord lesion development (95% CrI = [+ 37.4-fold, + 3239.5-fold]) was observed with traditional agents (p < 0.0001).

CONCLUSION

High-efficacy treatments maximize opportunity for preventing disease advancement in newly diagnosed and established pwNMOSD.

Perspective for Discovery of Small Molecule IL-6 Inhibitors through Study of Structure–Activity Relationships and Molecular Docking

Interleukin-6 (IL-6) is a proinflammatory cytokine that plays a key role in the pathogenesis and physiology of inflammatory and autoimmune diseases, such as coronary heart disease, cancer, Alzheimer's disease, asthma, rheumatoid arthritis, and most recently COVID-19. IL-6 and its signaling pathway are promising targets in the treatment of inflammatory and autoimmune diseases. Although, anti-IL-6 monoclonal antibodies are currently being used in clinics, huge unmet medical needs remain because of the high cost, administration-related toxicity, lack of opportunity for oral dosing, and potential immunogenicity of monoclonal antibody therapy. Furthermore, nonresponse or loss of response to monoclonal antibody therapy has been reported, which increases the importance of optimizing drug therapy with small molecule drugs. This work aims to provide a perspective for the discovery of novel small molecule IL-6 inhibitors by the analysis of the structure-activity relationships and computational studies for protein-protein inhibitors targeting the IL-6/IL-6 receptor/gp130 complex.

Decipher potential biomarkers of diagnosis and disease activity for NMOSD with AQP4 using LC-MS/MS and Simoa

BACKGROUND

Neuromyelitis optica spectrum disorders (NMOSD) is an autoimmune demyelinating disease, leading recurrently relapses and severe disability. There is a need for new biomarkers to meet clinical needs in diagnosis and monitoring.

METHODS

Through liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS) analysis, brain lesions from NMO animal models were analyzed to identify potential biomarkers. Then, we assessed the levels of serum glial fibrillary acidic protein (sGFAP), neurofilament light chain (sNfL), Tau protein (sTau) and Ubiquitin C-terminal hydrolase L1 (sUCHL1) using an ultrasensitive single molecule array (Simoa) of AQP4-IgG + NMOSD patients, myelin oligodendrocyte glycoprotein antibody-associated disorder (MOGAD) patients, multiple sclerosis (MS) patients and healthy controls (HCs). Additionally, we further explored the early diagnosis value of these proteins.

RESULTS

There were 72 differentially expressed proteins between the NMO and control groups. NfL abundance was elevated when GFAP, UCHL1, and Tau abundance was decreased in the NMO group. Then, we observed that the sGFAP and sUCHL1 levels in patients with NMOSD in the early stage were significantly increased compared to those in control participants. Combined ROCs of the sGFAP, sNfL, and sUCHL1 levels to better predict NMOSD with relapse stages was optimal. Notably, univariate and multivariate analyses demonstrated that the sGFAP and sNfL levels were higher in patients with brain lesions, while the sUCHL1 levels were higher in those with spinal cord lesions during recent relapse.

CONCLUSIONS

These findings suggested that sGFAP, sNfL, and sUCHL1 displayed good diagnostic performance in AQP4-IgG + NMOSD and could be novel candidates for early discrimination.

Secreted aminoacyl-tRNA synthetase-interacting multifunctional protein-1 (AIMP1) is a promising predictor for the severity of acute AQP4-IgG positive neuromyelitis optica spectrum disorder

BACKGROUND AND OBJECTIVES

Aminoacyl-tRNA synthetase complex interacting with multifunctional protein-1 (AIMP1) has been reported to carry pro-inflammatory properties and anti-angiogenesis effects. However, the exact role of AIMP1 in patients with NMOSD is not yet clear. Our objective was to investigate the relationship between plasma AIMP1 levels and disease severity in patients with AQP4-IgG⁺ NMOSD from North China based on the Expanded Disability Status Scale (EDSS) score.

METHODS

Plasma AIMP1 levels were measured using ELISA kits in 94 patients with AQP4-IgG⁺NMOSD (48 in the acute phase before high-dose intravenous methylprednisolone (IVMP) therapy, 21 in the acute phase after IVMP therapy, 25 in the clinical remission-phase)as well as 33 healthy controls (HCs). The disability function of NMOSD patients was evaluated using the EDSS score. Furthermore, the clinical characteristics of the patients were also evaluated, and laboratory tests were performed on blood samples.

RESULTS

The plasma AIMP1 levels in AQP4-IgG⁺NMOSD patients with acute phase before IVMP therapy were significantly higher as compared to those in patients after the IVMP therapy (p < 0.001) as well as those in the clinical remission phase (p = 0.021) or HCs (p < 0.001). Plasma AIMP1 levels were positively correlated with EDSS scores (r = 0.485, p < 0.001) and negatively correlated with serum complement 3 concentrations (r =-0.452, p = 0.001). AIMP1 exhibited the potential to distinguish NMOSD from HCs (AUROC 0.820, p < 0.0001) and could differentiate mild and moderate-severe NMOSD (AUROC 0.790, p = 0.0006). Furthermore, plasma AIMP1 levels of ≥49.55pg/mL were found to be an independent predictor of the risk for moderate-severe NMOSD (with OR 0.03, 95%CI 0.001-0.654, p = 0.026).

CONCLUSION

AIMP1 may be involved in the pathogenesis of AQP4-IgG⁺NMOSD disease and predict the disease activity, severity, or effect of treatment in patients with NMOSD. Further studies should be performed to reveal the precise mechanisms of AQP4-IgG⁺NMOSD.

Batoclimab as an add-on therapy in neuromyelitis optica spectrum disorder patients with acute attacks

BACKGROUND AND PURPOSE

Neuromyelitis optica spectrum disorder (NMOSD) is a severe neurological inflammatory disease mainly caused by pathogenic aquaporin-4 antibodies (AQP4-IgG). The safety and efficacy of the neonatal Fc receptor antagonist batoclimab addition to conventional intravenous methylprednisolone pulse (IVMP) therapy in patients with NMOSD acute attacks was assessed.

METHODS

In an open-label, dose-escalation phase 1b study, NMOSD patients with acute myelitis and/or optic neuritis received four doses of weekly subcutaneous injections of either 340 mg or 680 mg batoclimab with concurrent IVMP and were followed up for 27 weeks. The primary end-points were safety and tolerability. Secondary end-points included pharmacodynamics and efficacy, with key efficacy assessment at week 4.

RESULTS

In total nine NMOSD patients were enrolled, including two and seven in the 340 and 680 mg groups. Five patients had acute myelitis, while the remaining four had unilateral optic neuritis. Batoclimab add-on therapy had an overall good safety profile without serious adverse events. In the 680 mg group, mean immunoglobulin G (IgG) reached its maximum reduction at the last dose (day 22). In the meantime, AQP4-IgG was undetectable in six of seven subjects whose baseline AQP4-IgG titers ranged from 1:32 to 1:320. Expanded Disability Status Scale score was reduced by 1.3 ± 0.4 at week 4 (2.7 ± 1.3) compared with baseline (4.0 ± 1.0).

CONCLUSIONS

Batoclimab add-on therapy to IVMP is safe and tolerated in patients with NMOSD. Preliminary evidence suggests a beneficial neurological effect. A randomized controlled trial would be needed to prove the efficacy.

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.

Current view on the diagnosis and treatment of neuromyelitis optica spectrum disorders exacerbations

Irreversible neurological deficit and disability in neuromyelitis optica spectrum disorders (NOSD) are formed as a result of exacerbations, which are often life-threatening. Timely diagnosis and treatment of exacerbations is a key task in the management of this category of patients. A unified structured approach to the diagnosis and treatment of NOSD exacerbations has not been developed. The purpose of this article is to analyze the scientific literature data on this issue in order to optimize the diagnostics and treatment of NOSD exacerbations in everyday clinical practice. 

The cytokines interleukin-6 and interferon-α induce distinct microglia phenotypes

Background

Elevated production of the cytokines interleukin (IL)-6 or interferon (IFN)-α in the central nervous system (CNS) is implicated in the pathogenesis of neurological diseases such as neuromyelitis optica spectrum disorders or cerebral interferonopathies, respectively. Transgenic mice with CNS-targeted chronic production of IL-6 (GFAP-IL6) or IFN-α (GFAP-IFN) recapitulate important clinical and pathological features of these human diseases. The activation of microglia is a prominent manifestation found both in the human diseases and in the transgenic mice, yet little is known about how this contributes to disease pathology.

Methods

Here, we used a combination of ex vivo and in situ techniques to characterize the molecular, cellular and transcriptomic phenotypes of microglia in GFAP-IL6 versus GFAP-IFN mice. In addition, a transcriptomic meta-analysis was performed to compare the microglia response from GFAP-IL6 and GFAP-IFN mice to the response of microglia in a range of neurodegenerative and neuroinflammatory disorders.

Results

We demonstrated that microglia show stimulus-specific responses to IL-6 versus IFN-α in the brain resulting in unique and extensive molecular and cellular adaptations. In GFAP-IL6 mice, microglia proliferated, had shortened, less branched processes and elicited transcriptomic and molecular changes associated with phagocytosis and lipid processing. In comparison, microglia in the brain of GFAP-IFN mice exhibited increased proliferation and apoptosis, had larger, hyper-ramified processes and showed transcriptomic and surface marker changes associated with antigen presentation and antiviral response. Further, a transcriptomic meta-analysis revealed that IL-6 and IFN-α both contribute to the formation of a core microglia response in animal models of neurodegenerative and neuroinflammatory disorders, such as Alzheimer’s disease, tauopathy, multiple sclerosis and lipopolysaccharide-induced endotoxemia.

Conclusions

Our findings demonstrate that microglia responses to IL-6 and IFN-α are highly stimulus-specific, wide-ranging and give rise to divergent phenotypes that modulate microglia responses in neuroinflammatory and neurodegenerative diseases.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12974-022-02441-x.

Analysis of Predictive Risk Factors in Aquaporin-4-IgG Positive Highly Active Neuromyelitis Optica Spectrum Disorders

Neuromyelitis optica spectrum disorders (NMOSDs) are inflammatory diseases with a high risk of recurrence and progressive disability, and it is crucial to find sensitive and reliable biomarkers for prognosis and the early prediction of relapse. Highly active NMOSD is defined as two or more clinical relapses within a 12-month period. In this study, we analyzed independent risk factors among patients with aquaporin-4 (AQP4)-IgG positive highly active NMOSD. In this retrospective study, we analyzed the data of 94 AQP4-IgG positive patients with highly active NMOSD and 105 AQP4-IgG positive controls with non-highly active NMOSD. In order to rule out possible effects of previous treatments (such as glucocorticoids, immunoglobulin, and immunosuppressants), we focused on the first-attack NMOSD patients admitted to our hospital. Clinical data, including the age of onset, gender, comorbidities, and serum analysis and cerebrospinal fluid (CSF) analysis results, were collected, after which logistic regression models were used to determine the associations between the clinical factors and relapse outcomes. The prevalence of connective tissue disease and the proportion of antinuclear antibody (ANA)-positivity were higher in the highly active NMOSD group than in the control group. The leukocyte counts, homocysteine (Hcy) levels, CSF leukocyte counts, protein concentrations, IgG indexes, and 24h IgG synthesis rates were also higher in the highly active NMOSD group. The results of multivariate analysis indicated that connective tissue disease comorbidity (OR = 5.953, 95% CI: 1.221–29.034, P = 0.027), Hcy levels (OR = 1.063, 95% CI: 1.003–1.126, P = 0.04), and 24h IgG synthesis rate (OR = 1.038, 95% CI: 1.003–1.075, P = 0.034) may be independent risk factors for AQP4-IgG positive highly active NMOSD relapse after adjusting for various variables. Comorbidity of connective tissue disease, Hcy levels, and 24h IgG synthesis rate may be independent risk factors for AQP4-IgG positive highly active NMOSD.

Treatment of Neuromyelitis Optica Spectrum Disorders

Neuromyelitis optica spectrum disorder (NMOSD) is an autoimmune central nervous system (CNS) inflammatory disorder that can lead to serious disability and mortality. Females are predominantly affected, including those within the reproductive age. Most patients develop relapsing attacks of optic neuritis; longitudinally extensive transverse myelitis; and encephalitis, especially brainstem encephalitis. The majority of NMOSD patients are seropositive for IgG autoantibodies against the water channel protein aquaporin-4 (AQP4-IgG), reflecting underlying aquaporin-4 autoimmunity. Histological findings of the affected CNS tissues of patients from in-vitro and in-vivo studies support that AQP4-IgG is directly pathogenic in NMOSD. It is believed that the binding of AQP4-IgG to CNS aquaporin-4 (abundantly expressed at the endfoot processes of astrocytes) triggers astrocytopathy and neuroinflammation, resulting in acute attacks. These attacks of neuroinflammation can lead to pathologies, including aquaporin-4 loss, astrocytic activation, injury and loss, glutamate excitotoxicity, microglial activation, neuroinflammation, demyelination, and neuronal injury, via both complement-dependent and complement-independent pathophysiological mechanisms. With the increased understanding of these mechanisms underlying this serious autoimmune astrocytopathy, effective treatments for both active attacks and long-term immunosuppression to prevent relapses in NMOSD are increasingly available based on the evidence from retrospective observational data and prospective clinical trials. Knowledge on the indications and potential side effects of these medications are essential for a clear evaluation of the potential benefits and risks to NMOSD patients in a personalized manner. Special issues such as pregnancy and the coexistence of other autoimmune diseases require additional concern and meticulous care. Future directions include the identification of clinically useful biomarkers for the prediction of relapse and monitoring of the therapeutic response, as well as the development of effective medications with minimal side effects, especially opportunistic infections complicated by long-term immunosuppression.

Cladribine suppresses disease activity in neuromyelitis optica spectrum disorder: a 2-year follow-up study

BACKGROUND AND PURPOSE

Neuromyelitis optica spectrum disorder (NMOSD) is a difficult condition to treat. Cladribine selectively and transiently depletes B and T lymphocytes, leading to long-lasting immune reconstitution. This report describes observations from 24 months of follow-up after cladribine in NMOSD patients.

METHODS

This is a retrospective analysis of a case series including 12 seropositive patients with NMOSD. Patients were given cladribine by subcutaneous injections in a series of several 2-day cycles of 20 mg administered at intervals of 4-6 weeks. Thus, the full treatment course delivered a cumulative bioavailable dose similar to that approved for treatment of multiple sclerosis. Annualized relapse rate (ARR), disability (Expanded Disability Status Scale [EDSS] score) and safety in the 24 months preceding and the 24 months following the initiation of cladribine treatment were assessed.

RESULTS

The mean ARR in the 24 months preceding cladribine treatment was 1.04 (95% confidence interval [CI] 0.67-1.62). The mean ARR in the 24 months following initiation of cladribine treatment was 0.21 (95% CI 0.08-0.56). The ratio in the rate of events post versus prior cladribine initiation was 0.20 (95% CI 0.07-0.59) and highly significant (p = 0.0073). The EDSS score did not change over the follow-up period (2.5 ± 1.7; mean ± SD) compared to baseline (2.5 ± 1.5; mean ± SD). No serious adverse events considered to be linked to cladribine were observed during follow-up.

CONCLUSIONS

Cladribine was safe in NMOSD patients over a 2-year observation period. Cladribine treatment was associated with clinical stabilization, as evidenced by significantly decreased ARR and no progression of EDSS score.