Blood sphingolipid as a novel biomarker in patients with neuromyelitis optica spectrum disorder

BACKGROUND

Sphingolipids are signaling molecules and structural components of the axolemma and myelin sheath. Plasma sphingolipid levels may reflect disease status of neuromyelitis optica spectrum disorder (NMOSD). We aimed to examine plasma sphingolipids as disease severity biomarkers for NMOSD and compare their characteristics with those of serum neurofilament light chain (sNfL) and glial fibrillary acidic protein (sGFAP).

METHODS

We measured plasma sphingolipids, sNfL, and sGFAP levels in NMOSD cases with anti-aquaporin-4-antibody. An unbiased approach, partial least square discriminant analysis (PLS-DA), was utilized to determine whether sphingolipid profiles differ according to the disease state of NMOSD (presence, moderate-to-severe disability [Expanded Disease Severity Scale, (EDSS) > 3.0], and relapses).

RESULTS

We investigated 81 patients and 10 controls. PLS-DA models utilizing sphingolipids successfully differentiated patients with EDSS > 3.0, but failed to identify the presence of disease and relapses. Ceramide-C14-a significant contributor to differentiating EDSS > 3.0-positively correlated with EDSS, while its levels were independent of age and the presence of relapses. This characteristic was unique from those of sNfL and sGFAP, which were affected by age and relapses as well as EDSS.

CONCLUSION

Plasma sphingolipids may be useful NMOSD biomarkers for disability with distinct characteristics compared to sNfL and sGFAP.

Astrocytic outer retinal layer thinning is not a feature in AQP4-IgG seropositive neuromyelitis optica spectrum disorders

BACKGROUND

Patients with anti-aquaporin-4 antibody seropositive (AQP4-IgG+) neuromyelitis optica spectrum disorders (NMOSDs) frequently suffer from optic neuritis (ON) leading to severe retinal neuroaxonal damage. Further, the relationship of this retinal damage to a primary astrocytopathy in NMOSD is uncertain. Primary astrocytopathy has been suggested to cause ON-independent retinal damage and contribute to changes particularly in the outer plexiform layer (OPL) and outer nuclear layer (ONL), as reported in some earlier studies. However, these were limited in their sample size and contradictory as to the localisation. This study assesses outer retinal layer changes using optical coherence tomography (OCT) in a multicentre cross-sectional cohort.

METHOD

197 patients who were AQP4-IgG+ and 32 myelin-oligodendrocyte-glycoprotein antibody seropositive (MOG-IgG+) patients were enrolled in this study along with 75 healthy controls. Participants underwent neurological examination and OCT with central postprocessing conducted at a single site.

RESULTS

No significant thinning of OPL (25.02±2.03 µm) or ONL (61.63±7.04 µm) were observed in patients who were AQP4-IgG+ compared with patients who were MOG-IgG+ with comparable neuroaxonal damage (OPL: 25.10±2.00 µm; ONL: 64.71±7.87 µm) or healthy controls (OPL: 24.58±1.64 µm; ONL: 63.59±5.78 µm). Eyes of patients who were AQP4-IgG+ (19.84±5.09 µm, p=0.027) and MOG-IgG+ (19.82±4.78 µm, p=0.004) with a history of ON showed parafoveal OPL thinning compared with healthy controls (20.99±5.14 µm); this was not observed elsewhere.

CONCLUSION

The results suggest that outer retinal layer loss is not a consistent component of retinal astrocytic damage in AQP4-IgG+ NMOSD. Longitudinal studies are necessary to determine if OPL and ONL are damaged in late disease due to retrograde trans-synaptic axonal degeneration and whether outer retinal dysfunction occurs despite any measurable structural correlates.

Frequency of New Silent MRI Lesions in Myelin Oligodendrocyte Glycoprotein Antibody Disease and Aquaporin-4 Antibody Neuromyelitis Optica Spectrum Disorder

IMPORTANCE

In multiple sclerosis, magnetic resonance imaging (MRI) new silent lesions contribute to the diagnostic criteria, have prognostic value, and are used in treatment monitoring; but in aquaporin-4 antibody neuromyelitis optica spectrum disorder (AQP4-NMOSD), they are rare between attacks. Their frequency and their association with relapses in adults with myelin oligodendrocyte glycoprotein antibody disease (MOGAD) are still unclear.

OBJECTIVE

To examine the frequency and characteristics of MRI new silent lesions in MOGAD and AQP4-NMOSD.

DESIGN, SETTING, AND PARTICIPANTS

This retrospective cohort study analyzed clinical and MRI data of 404 patients with MOGAD or AQP4-NMOSD between February 1, 1994, and April 1, 2021; data were prospectively recorded on the Oxford NMOSD clinical database under follow-up. The study was conducted at the Oxford National Referral Center for NMOSD. Participants included patients with MOGAD and AQP4-NMOSD who were treated within the Oxford National NMO Specialist Service.

EXPOSURES

Seropositive MOGAD and AQP4-NMOSD patients who had MRIs during attacks and the remission phase of their disease.

MAIN OUTCOMES AND MEASURES

Frequency of new silent lesions detected by either attack MRIs (during the acute clinical event) or remission MRIs (performed outside of a relapse and at least 3 months from last attack). Median time to next relapse in the presence of definite (reference MRI performed at least 4 weeks from last attack onset), probable (reference MRI performed during last attack), and no new silent lesions on remission MRIs was also evaluated.

RESULTS

One hundred eighty-two MOGAD patients and 222 AQP4-NMOSD patients were included. Of the MOGAD patients, 113 (62%) were female, median age at onset was 28 years (range, 2-72), and median follow-up was 52 months (range, 11-253). Of the AQP4-NMOSD patients, 189 (85%) were female, median age at onset was 43 years (range, 2-82), and median follow-up was 87.5 months (range, 11-260). MOGAD patients had 296 attack MRI sessions and 167 remission MRI sessions. New attack silent lesions were found in 97 of 296 (33%) attack MRI sessions, whereas new remission silent lesions were found in 5 of 167 (3.0%) remission MRI sessions. Median time from remission scan to the next relapse in the presence of definite or probable new remission lesions was 2 months (IQR, 1-6), whereas in the absence of any new remission lesions it was 73 months (IQR, 20-104; hazard ratio, 23.86; 95% CI, 7.51-75.79; P < .001). AQP4-NMOSD patients had 470 attack MRI sessions and 269 remission MRI sessions. New attack silent lesions were detected in 88 of 470 (18.7%) attack MRI sessions, whereas new remission silent lesions were found in 7 of 269 (2.6%) remission MRI sessions. Median time from remission scan to the next relapse in the presence of definite or probable new remission lesions was 5 months (IQR, 2-6), whereas in the absence of any new remission lesions it was 85 months (IQR, 29-167; hazard ratio, 21.23; 95% CI, 8.05-53.65; P < .001).

CONCLUSIONS AND RELEVANCE

In contrast to that reported in multiple sclerosis, results of this cohort study suggest that new remission silent lesions are rare on follow-up scans in MOGAD and AQP4-NMOSD and appear to indicate a high risk of imminent relapse.

Comparative study of AQP4 antibody-related diseases and MOG antibody-related diseases among the population in Hunan, China

To compare the clinical, imaging, and prognostic characteristics of AQP4 antibody-related diseases and MOG antibody-related diseases. The clinical data of 56 AQP4 antibody-positive patients and 14 MOG antibody-positive patients in the Second Xiangya Hospital of Central South University from June 2016 to June 2019 were collected. 92.9% of the patients with positive AQP4 antibody were females and 64.3% of patients with positive MOG antibody were females (P = 0.004). Patients with positive AQP4 antibody were more likely to have limb movement (P < 0.001) or limb sensory dysfunction (P < 0.001), and were more likely to have limb twitching (P = 0.036). In addition, AQP4 antibody-positive patients were more likely to have positive ANA (P = 0.013) and SSA antibody (P = 0.029), Ro-52 antibody (P = 0.047), immunoglobulin (P = 0.007), thyroid antibody (P = 0.007), abnormal C3 (P = 0.011), abnormal C4 (P = 0.014) than MOG antibody-positive patients. The involvement rate of head in MOG antibody-positive patients was higher than AQP4 antibody-positive patients (P = 0.029). The severity of clinical symptoms in AQP4-positive patients was usually more serious than that in MOG-positive patients (P < 0.001). The residual neurological deficit after treatment in AQP4-positive group was usually more serious than that in MOG-positive group (P < 0.001). AQP4 antibody-positive patients had a higher prevalence in women than MOG antibody-positive patients, and AQP4 antibody-positive patients were more likely to have spinal cord involvement symptoms and connective tissue antibody abnormalities. The EDSS score of them were higher than that of MOG antibody-positive patients after treatment, and the prognosis was worse.

Prolonged B-cell depletion after rituximab in AQP4-IgG-positive neuromyelitis optica spectrum disorder

Rituximab (a B-cell depleting monoclonal antibody) is increasingly utilized for treatment of different immune-mediated neurologic disorders, including aquaporin-4-IgG-positive neuromyelitis optica spectrum disorder (AQP4-IgG-NMOSD). After an initial treatment course, the drug is generally reinfused when peripheral blood B-cells levels re-increase >1% (usually after 6-12 months), or at fixed pre-planned 6-month intervals. We describe the unusual case of a 40-year-old woman with AQP4-IgG-NMOSD who showed a prolonged B-cell depletion for nearly five years after a single rituximab reinfusion. In similar rare patients with exceptionally long-lasting B-cell depletion, rituximab reinfusions at fixed pre-planned intervals would result in unnecessary treatment-related risks and health-care expenses.

Epstein-Barr virus infection in a woman with aquaporin-4 seropositive neuromyelitis optica

Neuromyelitis optica spectrum disorders (NMOSD) are characterised by pathological antibodies to aquaporin-4 water channels of astrocytes, resulting in severe brain and spinal cord injury. Serological evidence suggests that Epstein-Barr virus (EBV) reactivation may contribute to their pathogenesis. We describe an unusual case of a woman with fever, rash and headache preceding an Aquaporin-4 antibody positive longitudinally extensive transverse myelitis. EBV was detected in her cerebrospinal fluid by polymerase chain reaction assay. This case highlights the potential role of EBV in the pathogenesis of NMOSD.

Neuromyelitis Optica Spectrum Disorder Complicated by Posterior Reversible Encephalopathy Syndrome as an Initial Manifestation

A 25-year-old woman was admitted to our hospital due to tonic convulsion with severe headache after having experienced symptoms of nausea and vomiting for a month. Brain magnetic resonance imaging showed extensive symmetrical lesions in the cortical and subcortical areas of parieto-occipital lobes and basal ganglia, consistent with typical characteristics of posterior reversible encephalopathy syndrome (PRES). Furthermore, some residual lesions in the left side of dorsal medulla oblongata and central area of the cervical spinal cord along with the presence of serum anti-aquaporin-4 antibody yielded the diagnosis of neuromyelitis optica spectrum disorder (NMOSD). We herein discuss the mechanism by which PRES may occur together with NMOSD.

HLA-G Ins/Del polymorphism and +3142C/G SNP are not related to neuromyelitis optica spectrum disorder (NMOSD) development, disability status or anti-aquaporin 4 presence in Brazilian patients

We analyzed the association of polymorphisms from the 3' untranslated region of the HLA-G gene in 70 neuromyelitis optica spectrum disorder (NMOSD) patients and 162 healthy controls. No associations were found between the polymorphisms in NMOSD when compared to healthy controls, serology of the anti-AQP4 NMOSD biomarker and Expanded Disability Status Scale (EDSS). In conclusion, the 3' untranslated region 14 bp Ins/Del and +3142C/G polymorphisms seem not to be associated with NMOSD susceptibility, autoantibody production, nor a neurological deficit in patients.

Clinical and radiological characteristics of neuromyelitis optica spectrum disorder in the North Egyptian Nile Delta

BACKGROUND

Neuromyelitis optica spectrum disorder (NMOSD) is an autoimmune demyelinating disorder of the central nervous system that was previously thought to be a subtype of multiple sclerosis (MS). Epidemiology studies of NMOSD are rare in both Middle East and North African countries. To our knowledge, there are no such studies in Egypt. Herein, we describe a case series of NMOSD patients from North Egyptian Nile Delta region and compare them to NMOSD in other parts in the Middle East and the world.

METHODS

This is a case series study of NMOSD patients who were seen at the neuroimmunology clinic, Elhadara Hospital, University of Alexandria, Egypt, from January 2017 to January 2018. We describe their clinical, serological and radiological features.

RESULTS

Our study identified twenty Egyptian patients, all of who fulfilled the 2015 international NMOSD diagnostic criteria. Ten tested positive for AQP4 antibodies in the serum while the other ten were seronegative. The mean age at onset was 27.8 years with an average disease duration of 6.8 years. There was a strong female predominance with a ratio of 5.6:1. We identified clinical features of the cohort that differ from those reported in other worldwide studies.

INTERPRETATION

This is the first NMOSD case series in Egypt. Despite some limitation in testing and access to care, there are features of our NMOSD cases that appear to be different from other worldwide cohorts reported in the literature.

Increased expression of the membrane-bound CD40 ligand on peripheral CD4+ T cells in the acute phase of AQP4-IgG-seropositive neuromyelitis optica spectrum disorders

Currently, no data are available regarding the expression levels of CD40L on CD4⁺ T cells in patients with neuromyelitis optica spectrum disorders (NMOSD). The percentage of circulating CD40L⁺CD4⁺ T cells was measured by flow cytometry in 23 NMOSD patients and 10 healthy controls. The ratio of CD40L⁺CD4⁺ to CD4⁺ T cells in patients at acute phase (18.28 ± 15.56%) was significantly higher than that in healthy controls (7.23 ± 5.94%, P = .032) and was positively correlated with disease severity (r = 0.532, P = .041). Thus, our results suggest an important role of this molecule in acute attacks of NMOSD.

Transient Pulmonary Interstitial Lesions in Aquaporin-4-positive Neuromyelitis Optica Spectrum Disorder

We herein report the case of a 76-year old man with aquaporin-4-Immunoglobulin-G (AQP4-IgG)-positive neuromyelitis optica spectrum disorder (NMOSD), in whom transient interstitial pulmonary lesions developed at the early stage of the disease. Chest X-ray showed multiple infiltrative shadows in both upper lung fields, and computed tomography revealed abnormal shadows distributed randomly in the lungs. Surgical lung biopsy showed features of unclassifiable interstitial pneumonia, characterized by various types of air-space organization, which resulted in obscure lung structure. This is the first report to describe the pathological findings of interstitial pneumonia, which may represent a rare extra-central nervous system complication of NMOSD.

MRI Features of Aquaporin-4 Antibody-Positive Longitudinally Extensive Transverse Myelitis: Insights into the Diagnosis of Neuromyelitis Optica Spectrum Disorders

BACKGROUND AND PURPOSE

Longitudinally extensive transverse myelitis is a well-documented spinal manifestation of neuromyelitis optica spectrum disorders, however, other forms of nontumorous myelopathy can also manifest as longitudinally extensive transverse myelitis. Our aim was to evaluate the MR imaging features of aquaporin-4 antibody-positive longitudinally extensive transverse myelitis, which is strongly associated with neuromyelitis optica spectrum disorders.

MATERIALS AND METHODS

We evaluated cervicomedullary junction involvement, cord expansion ratios, bright spotty lesions, the number of involved segments, skipped lesions, enhancement patterns, and axial distribution patterns using spinal MR imaging of 41 patients with longitudinally extensive transverse myelitis who underwent aquaporin-4 antibody testing. Univariate logistic regression analysis was performed to identify factors associated with aquaporin-4 antibody seropositivity, which were then used to develop a scoring system for diagnosing aquaporin-4 antibody-positive longitudinally extensive transverse myelitis. Interrater reliability for cord expansion ratio measurement and bright spotty lesions was determined using intraclass correlation coefficients and κ values, respectively.

RESULTS

Fifteen patients with longitudinally extensive transverse myelitis were aquaporin-4 antibody-positive. Sex (female), cervicomedullary junction involvement, a cord expansion ratio of >1.4, and bright spotty lesions were significantly associated with aquaporin-4 antibody seropositivity. The sensitivity and specificity of the scoring system were 73.3% and 96.2%, respectively. The interclass correlation value for the cord expansion ratio was 0.78, and the κ value for bright spotty lesions was 0.61.

CONCLUSIONS

Our scoring system, based on cervicomedullary junction involvement, higher cord expansion ratio, bright spotty lesions, and female sex, can facilitate the timely diagnosis of neuromyelitis optica spectrum disorders.

Relationship Between Neuromyelitis Optica Spectrum Disorder and Sjögren's Syndrome: Central Nervous System Extraglandular Disease or Unrelated, Co-Occurring Autoimmunity?

OBJECTIVE

Sjögren's syndrome (SS) patients may be affected by the neuromyelitis optica spectrum disorder (NMOSD), a severe demyelinating syndrome associated with anti-aquaporin 4 antibodies (anti-AQP-4 antibodies). The relationship between SS and NMOSD has been a sustained focus of investigation. Among SS patients, anti-AQP-4 antibodies have been detected exclusively in those with NMOSD. It has therefore been speculated that NMOSD is not a neurologic complication of SS. However, such studies evaluated small numbers of SS patients, often mixed with other inflammatory disorders.

METHODS

We compared frequencies of anti-AQP-4 and SS-associated antibodies in 109 SS patients, including 11 with NMOSD, 8 with non-NMOSD demyelinating syndromes, and 90 without demyelinating syndromes.

RESULTS

When assessed using a fluorescence-activated cell sorting (FACS) assay, anti-AQP-4 antibodies were seen exclusively in those SS patients with NMOSD (72.7%), but not in SS patients without NMOSD (P < 0.01). In contrast, anti-Ro 52, anti-Ro 60, and other autoantibodies were not more prevalent in SS patients with NMOSD versus those without. Anti-AQP-4 antibodies were detected more frequently among NMOSD patients by FACS assay than with a commercial immunohistochemical assay (72.7% versus 54.5%), despite assessment after a more prolonged period of immunosuppressive therapy (median 38 months versus 5 months; P < 0.01).

CONCLUSION

The syndrome-specificity of anti-AQP-4 antibodies, along with an otherwise similar antibody profile in SS NMOSD patients, indicates that NMOSD is not a direct central nervous system manifestation of SS. Anti-AQP-4 antibodies can persist and be refractory to prolonged immunosuppressive therapy.

Structural Alterations of Segmented Macular Inner Layers in Aquaporin4-Antibody-Positive Optic Neuritis Patients in a Chinese Population

Objectives

This study aimed to analyse the structural injury of the peripapillary retinal nerve fibre layer (pRNFL) and segmented macular layers in optic neuritis (ON) in aquaporin4-antibody (AQP4-Ab) seropositivity(AQP4-Ab-positiveON) patients and in AQP4-Ab seronegativity (AQP4-Ab-negative ON) patients in order to evaluate their correlations with the best-corrected visual acuity (BCVA) and the value of the early diagnosis of neuromyelitis optica (NMO).

Design

This is a retrospective, cross-sectional and control observational study.

Methods

In total, 213 ON patients (291 eyes) and 50 healthy controls (HC) (100 eyes) were recruited in this study. According to a serum AQP4-Ab assay, 98 ON patients (132 eyes) were grouped as AQP4-Ab-positive ON and 115 ON patients (159 eyes) were grouped as AQP4-Ab-negative ON cohorts. All subjects underwent scanning with spectralis optical coherence tomography (OCT) and BCVA tests. pRNFL and segmented macular layer measurements were analysed.

Results

The pRNFL thickness in AQP4-Ab-positive ON eyes showed a more serious loss during 0–2 months (-27.61μm versus -14.47 μm) and ≥6 months (-57.91μm versus -47.19μm) when compared with AQP4-Ab-negative ON eyes. AQP4-Ab-positive ON preferentially damaged the nasal lateral pRNFL. The alterations in the macular ganglion cell layer plus the inner plexiform layer (GCIP) in AQP4-Ab-positive ON eyes were similar to those in AQP4-Ab-negative ON eyes. AQP4-Ab-positive ON eyes had entirely different injury patterns in the inner nuclear layer (INL) compared with AQP4-Ab-negative ON eyes during the first 6 months after the initial ON attack. These differences were as follows: the INL volume of AQP4-Ab-positive ON eyes had a gradual growing trend compared with AQP4-Ab-negative ON eyes, and it increased rapidly during 0–2 months, reached its peak during 2–4 months, and then decreased gradually. The pRNFL and GCIP in AQP4-Ab-positive ON eyes had positive correlations with BCVA. When the pRNFL thickness decreased to 95%CI (50.77μmto 60.85μm) or when the GCIP volume decreased to 95%CI (1.288 mm³to 1.399 mm³), BCVA began to be irreversibly damaged.

Conclusion

The structural alterations of pRNFL and GCIP could indicate the resulting visual damage. In addition, the injury pattern of INL could be a potential structural marker to predict the conversion of ON to NMO.

Elevation of AQP4 and selective cytokines in experimental autoimmune encephalitis mice provides some potential biomarkers in optic neuritis and demyelinating diseases

Idiopathic optic neuritis (ION) is an inflammation of the optic nerve that may result in a complete or partial loss of vision. ION is usually due to the immune attack of the myelin sheath covering the optic nerve. ION acts frequently as the first symptoms of multiple sclerosis (MS) and neuromyelitis optica (NMO), or other inflammatory demyelinating disorders. The pathogenic progression of ION remains unclear. Experimental autoimmune encephalitis (EAE) is a commonly used model of idiopathic inflammatory demyelinating disorders (IIDDs); the optic nerve is affected in EAE as well. The specific mediators of demyelination in optic neuritis are unknown. Recent studies have indicated what T-cell activation in peripheral blood is associated with optic neuritis pathogenesis. The object of the present study was to determine whether certain cytokines (IL-6, IL-17A, and IL-23) and AQP4 contribute to the demyelinating process using EAE model. We have found that IL-6R, AQP4 and IL-23R are significantly increased in mRNA and protein levels in optic nerves in EAE mice compared to control mice; serum AQP4, IL-6, IL-17A, IL-23 are increased whereas transforming growth factor beta (TGF-β) is decreased in EAE mice. These results suggest that AQP4 and selective cytokines in serum are associated with ION pathogenesis in the animal model, and these results shine light for future clinical diagnosis as potential biomarkers in ION patients.

[Effect of xingnaojing injection combined with minimally invasive percutaneous drainage in treating brain edema and content of serum AQP4 in patients with moderate hypertensive basal ganglia hemorrhage]

OBJECTIVE

To observe the effect of Xingnaojing Injection combined with minimally invasive percutaneous drainage on brain edema and content of serum aquaporin-4 (AQP4) in patients with moderate hypertensive basal ganglia hemorrhage, and discuss the treatment mechanism of Xingnaojing injection combined with minimally invasive percutaneous drainage for cerebral hemorrhage.

METHOD

Forty-two patients with moderate (25-50 mL) hypertensive basal ganglia hemorrhage (< 24 h) were selected and randomly divided into two groups: the observation group (n = 22) and the control group (n = 20). The neurological severity score were evaluated by the NIHSS (national institutes of health stroke scale), the volume of brain edemas were measured by head CT, the serum levels of AQP4 were determined by ELISA method on admission and 1 and 2 weeks after treatment.

RESULT

On admission, there was no significant difference in the scores of NIHSS, the volume of brain edemas and the level of serum AQP4 between the observation group and the control group. At the end of the first week after the treatment, the score of NIHSS of the observation group were lower than that of the control group, with significant different (P < 0.05); the observation group showed reduced volume of brain edemas than that on admission (P < 0.05), whereas the control group the control group showed increased volume of brain edemas than that on admission; the control group displayed increased level of serum AQP4 than that on admission, but without significant difference; the observation group displayed decreased level of serum AQP4 than that on admission (P < 0.05). At the end of the second week after the treatment, the control group showed decreased score of NIHSS than that on admission and at the end of the first week after treatment (P < 0.05). Compared with the control group, the observation group showed a much lower score of NIHSS (P < 0.01), the control group displayed reduced volume of brain edemas than that on admission and at the end of the first week after treatment, but the observation group was even lower than the control group. Both of observation and control groups displayed significantly reduced level of AQP4 (P < 0.05), but the observation group showed a lower AQP4 level than that of the control group (P < 0.05).

CONCLUSION

The therapy of Xingnaojing injection combined with minimally invasive percutaneous drainage could remarkably reduce brain edema, and promote neural functional recovery, thus could be selected as a therapeutic regimen for patients with moderate hypertensive basal ganglia hemorrhage.

Frequency of autoantibodies and connective tissue diseases in Chinese patients with optic neuritis

Background

Optic neuritis (ON) is often associated with other clinical or serological markers of connective tissue diseases (CTDs). To date, the effects of autoantibodies on ON are not clear.

Purpose

To assess the prevalence, clinical patterns, and short outcomes of autoantibodies and Sjögren’s syndrome (SS) involvement in Chinese ON patients and evaluate the relationship between ON, including their subtypes, and autoantibodies.

Methods

A total of 190 ON patients were divided into recurrent ON (RON), bilateral ON (BON), and isolated monocular ON (ION). Demographic, clinical, and serum autoantibodies data were compared between them with and without SS involvement. Serum was drawn for antinuclear antibody (ANA), extractable nuclear antigen antibodies (SSA/SSB), rheumatoid factor (RF), anticardiolipin antibodies (ACA), and anti-double-stranded DNA antibody (A-ds DNA), anticardiolipin antibody (ACLs), anti-β2-glycoprotein I (β2-GPI) and Aquaporin-4 antibodies (AQP4-Ab). Spectral-domain optical coherence tomography (SD-OCT) was used to evaluate the atrophy of the optic nerve.

Results

68 patients (35.79%) had abnormal autoantibodies, 26(13.68%) patients met diagnostic criteria for CTDs, including 15(7.89%) patients meeting the criteria for SS. Antibodies including SSA/SSB 23 (30.26%) (p1 and p 2<0.001) and AQP4–Ab10 (13.16%) (p1 = 0.044, p2 = 0.01) were significantly different in patients in the RON group when compared with those in the BON (P1 = RON VS ION) and ION (p2 = RON VS ION) groups. SS was more common in RON patients (p1 = 0.04, p2 = 0.028). There was no significant difference between SSA/SSB positive and negative patients in disease characteristics or severity. Similar results were obtained when SS was diagnosed in SSA/SSB positive patients.

Conclusion

RON and BON were more likely associated with abnormal autoantibodies; furthermore, AQP4 antibody, SSA/SSB and SS were more common in the RON patients. AQP4 antibodydetermination is crucial in RON patients who will develop NMO. However, when compared with other autoantibodies, SSA/SSB detected in patients was not significantly associated with disease characteristics or severity.

Evidence for humoral autoimmunity in neuromyelitis optica

Neuromyelitis optica (NMO) is an idiopathic central nervous system (CNS) demyelinating syndrome that may be distinguished from typical multiple sclerosis (MS). Although the cause of the disorder is not known, several lines of evidence suggest that the fundamental immunological process is driven by humoral mechanisms. These observations include the frequent coexistence of systemic autoimmune disease or positive serum autoantibodies with NMO, immunopathologic studies that demonstrate prominent complement activation and immunoglobulin deposition and the discovery of the serum autoantibody NMO-IgG, a potential NMO biomarker that targets aquaporin-4. Furthermore, clinical experience suggests that plasmapheresis and immunosuppressive therapies are beneficial for treatment and prevention of acute attacks but that standard MS immunomodulatory drugs may not alter the course of NMO. This evidence is reviewed in the context of its implications for future laboratory and clinical research in NMO.

[Pathogenesis of neuromyelitis optica]

Neuromyelitis optica (NMO) is a disease characterized by severe optic neuritis and transverse myelitis with autoantibody against aquaporin 4 (AQP4), mainly localized at astrocyte foot processes. Loss of AQP4 and glial fibrillary acidic protein with relatively preserved myelin is the pathological hallmarks of active NMO lesions. Several experimental studies suggested the crucial role of AQP4 antibody with diverse mechanisms including antibody- and complement-induced cytotoxicity against astrocytes. In vivo studies demonstrated that T cell-mediated CNS inflammation is necessary for the access of AQP4 antibody into CNS. NMO patients often develop medullary lesions including area postrema, which lacks the blood-brain-barrier and is sensitive to emetic agents. NMO is now considered to be an autoimmune astrocytopathy, and is distinct from multiple sclerosis.

[Detection of anti-aquaporin 4 antibody in neuromyelitis optical]

OBJECTIVE

To assess the sensitivity and specificity of anti-aquaporin 4 antibody in the diagnosis of neuromyelitis optical (NMO) and analyze the relationship between clinical features and different NMO-IgG status.

METHODS

A total of 269 serum specimens were collected from the patients with NMO, high-risk for NMO, multiple sclerosis (MS) and miscellaneous diseases and analyzed with HEK-293T cells transfected by aquaporin 4 cDNA. The sensitivity and specificity of anti-aquaporin 4 antibody in the diagnosis of NMO were calculated, Spearman correlation coefficients were used to examine the relationship between clinical features and antibody titer.

RESULTS

(1) The results of cell-based immunofluorescence assay showed 36 examples of 47 NMO patient serums (76.6%) were positive, 7/23 high-risk for NMO positive (30.4%), 3/85 multiple sclerosis (3.5%) positive, 1/48 miscellaneous neurological disorders (2.1%), 2/16 immune system diseases positive (12.5%) and negative in all 50 healthy serum specimens. Sensitivity and specificity were 76.6% and 97.0% for discriminating NMO from MS and other diseases. (2) Anti-AQP4 antibody titer had no obvious correlation to relapses, spinal lesion length and EDSS (P > 0.05). (3) Anti-AQP4 antibody titer became lower after a high dose of intravenous methylprednisolone (P < 0.05).

CONCLUSION

Anti-AQP4 antibody in NMO has a high specificity and sensitivity so as to contribute to early diagnosis and optimized treatment of NMO. And its titer decreases after a high dose of intravenous methylprednisolone. But there is no correlation between its titer and length of spinal cord lesions, relapsing frequency or expanded disability status scale (EDSS) score.

Anti-aquaporin-4 antibody-seronegative NMO spectrum disorder with Baló's concentric lesions

A 34-year-old woman developed simultaneous bilateral severe optic neuritis and subsequent myelitis. Two months after the first attack, she developed a headache and dysesthesia in the left arm. Brain magnetic resonance imaging revealed multiple hyperintense lesions in the white matter of the right hemisphere, some of which were Baló-like concentric lesions. Our diagnosis was neuromyelitis optica spectrum disorder with Baló's concentric sclerosis (BCS), although the patient was negative for anti-aquaporin-4 (anti-APQ4) antibodies. Our case suggests that Baló's concentric sclerosis overlaps with neuromyelitis optica spectrum disorder and that this overlapping is caused by a mechanism that does not involve anti-AQP4 antibodies.

Aquaporin-4 antibodies are not related to HTLV-1 associated myelopathy

Introduction

The seroprevalence of human T-cell leukemia virus type 1 (HTLV-1) is very high among Brazilians (∼1∶200). HTLV-1 associated myelopathy or tropical spastic paraparesis (HAM/TSP) is the most common neurological complication of HTLV-1 infection. HAM/TSP can present with an acute/subacute form of longitudinally extensive myelitis, which can be confused with lesions seen in aquaporin-4 antibody (AQP4-Ab) positive neuromyelitis optica spectrum disorders (NMOSD) on MRI. Moreover, clinical attacks in patients with NMOSD have been shown to be preceded by viral infections in around 30% of cases.

Objective

To evaluate the frequency of AQP4-Ab in patients with HAM/TSP. To evaluate the frequency of HTLV-1 infection in patients with NMOSD.

Patients and Methods

23 Brazilian patients with HAM/TSP, 20 asymptomatic HTLV-1+ serostatus patients, and 34 with NMOSD were tested for AQP4-Ab using a standardized recombinant cell based assay. In addition, all patients were tested for HTLV-1 by ELISA and Western blotting.

Results

20/34 NMOSD patients were positive for AQP4-Ab but none of the HAM/TSP patients and none of the asymptomatic HTLV-1 infected individuals. Conversely, all AQP4-Ab-positive NMOSD patients were negative for HTLV-1 antibodies. One patient with HAM/TSP developed optic neuritis in addition to subacute LETM; this patient was AQP4-Ab negative as well. Patients were found to be predominantly female and of African descent both in the NMOSD and in the HAM/TSP group; Osame scale and expanded disability status scale scores did not differ significantly between the two groups.

Conclusions

Our results argue both against a role of antibodies to AQP4 in the pathogenesis of HAM/TSP and against an association between HTLV-1 infection and the development of AQP4-Ab. Moreover, the absence of HTLV-1 in all patients with NMOSD suggests that HTLV-1 is not a common trigger of acute attacks in patients with AQP4-Ab positive NMOSD in populations with high HTLV-1 seroprevalence.

[Neuromyelitis optica with high aquaporin-4 expression and positive serum aquaporin-4 autoantibodies]

Disease-specific aquaporin-4 antibodies (NMO-IgG) are the main effector of lesions in neuromyelitis optica (NMO) patients. Brain MRI lesions are detected in 60% of them, with 8% (almost infants) at sites of high aquaporin-4 expression. Patient 1: A fifty-year-old male with loss of vision in the right eye. Empiric treatment with metilprednisolone 1g/d for 3 days was indicated. After 30 days he complained of generalized pain, and a right hemiparesis was evident. The patient received bolus of metilprednisolone 1g/d for 5 days plus IgG 400 mg/kg/d IV for 5 days. He recovered ambulation but persisted with pain and paroxysmal phenomena (Lhermitte). Visual Evoked Potentials (VEP): P100 left eye 123 ms, right eye without response. Brain MRI (FLAIR) showed hyperintensity in the right optic nerve, hypothalamus and anterior white commissure. Cervical MRI showed extensive spinal cord lesion to an extension of 5 vertebral bodies. Patient 2: A fifty-three-year-old female who referred decreased visual acuity in both eyes and paresthesia in lower limbs which subsided spontaneously. One month later the patient evolved with cuadriparesis and sphincter incontinence. No improvement was observed with bolus of metilprednisolone 1g/d for 5 day. VEP: P100 left eye 124 ms, right eye 128 ms. Brain MRI (FLAIR) disclosed hypothalamic and periaqueductal hyperintensity. Cervical MRI showed extensive spinal cord lesion to an extension of 7 vertebral bodies. NMO-IgG antibodies were positive in both patients (indirect immunofluorescence assay). NMO brain lesions at sites of high aquaporin-4 expression, once considered atypical for their topography and infrequency in adults, should be borne in mind when considering differential diagnosis.

Aquaporin 4 antibodies in the cerebrospinal fluid are helpful in diagnosing Chinese patients with neuromyelitis optica

OBJECTIVE

It was the aim of this study to compare the diagnostic efficiency of anti-aquaporin 4 (AQP4) antibody detection between serum and cerebrospinal fluid (CSF) samples in Chinese patients with central nervous system demyelinating diseases.

METHODS

Anti-AQP4 antibodies were detected by a cell-based assay. We calculated the sensitivity, specificity and coherence in 118 patients with neuromyelitis optica (NMO, n = 39), multiple sclerosis (n = 34), longitudinally extensive transverse myelitis (LETM, n = 22), optic neuritis (ON, n = 6), opticospinal multiple sclerosis (n = 8) and acute partial transverse myelitis (n = 9).

RESULTS

Forty-four serum samples (33.8%) were positive for anti-AQP4 antibodies. Anti-AQP4 antibody seropositivity was 76.9, 59.1 and 16.7% in patients with NMO, LETM and ON, respectively. Sixty-five CSF samples (50%) were positive for anti-AQP4 antibodies. Anti-AQP4 antibody positivity was 87.1, 81.8, 83.3, 62.5 and 11.8% in patients with NMO, LETM, ON, opticospinal multiple sclerosis and multiple sclerosis, respectively. The κ value of the coherence test was 0.585 (p < 0.0001) between the two types of samples. The antibody positivity rate was significantly different between the two body fluids (p = 0.0008, McNemar test). The sensitivity and specificity were 74.3 and 100% in serum, 85.7 and 88.2% in CSF, and 94.3 and 88.2% for serum and CSF combined, respectively.

CONCLUSION

The sensitivity of anti-AQP4 antibodies in the CSF was higher than that in the serum, and their combined use is helpful in diagnosing Chinese patients with NMO.