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

Update on the diagnosis and treatment of neuromyelits optica spectrum disorders (NMOSD) - revised recommendations of the Neuromyelitis Optica Study Group (NEMOS). Part I: Diagnosis and differential diagnosis

The term 'neuromyelitis optica spectrum disorders' (NMOSD) is used as an umbrella term that refers to aquaporin-4 immunoglobulin G (AQP4-IgG)-positive neuromyelitis optica (NMO) and its formes frustes and to a number of closely related clinical syndromes without AQP4-IgG. NMOSD were originally considered subvariants of multiple sclerosis (MS) but are now widely recognized as disorders in their own right that are distinct from MS with regard to immunopathogenesis, clinical presentation, optimum treatment, and prognosis. In part 1 of this two-part article series, which ties in with our 2014 recommendations, the neuromyelitis optica study group (NEMOS) gives updated recommendations on the diagnosis and differential diagnosis of NMOSD. A key focus is on differentiating NMOSD from MS and from myelin oligodendrocyte glycoprotein antibody-associated encephalomyelitis (MOG-EM; also termed MOG antibody-associated disease, MOGAD), which shares significant similarity with NMOSD with regard to clinical and, partly, radiological presentation, but is a pathogenetically distinct disease. In part 2, we provide updated recommendations on the treatment of NMOSD, covering all newly approved drugs as well as established treatment options.

Serum antinuclear antibodies associate with worse prognosis in AQP4-positive neuromyelitis optica spectrum disorder

BACKGROUND

Studies have demonstrated that antinuclear antibodies (ANAs) may be correlated with neuromyelitis optica spectrum disorder (NMOSD). However, the conflicting results of studies about the value of ANAs in AQP4 antibody-positive NMOSD patients need to be further investigated.

MATERIAL

Case data were collected from 143 patients with AQP4 antibody-positive NMOSD. Patients were divided into two groups based on the ANA test results. The analysis of clinical characteristics, laboratory tests, and MRI examination results were compared between two groups: the NMOSD patients with ANA (+) and with ANA (-).

RESULTS

Disease duration of NMOSD is shorter in the ANA (+) patients with EDSS < 4 than in the ANA (-) patients (12.05 ± 16.73 versus 29.43 ± 41.03, p-value = .013). The median time from disease onset to an EDSS score of 4.0 is significantly longer in the ANA (-) NMOSD patients than in the ANA (+) patients (48.2 months versus 24 months, p = .04). In addition, ANA (RR, 2.234; 95% CI, 1.078-4.629; p-value = .031) can predict the severity of NMOSD.

CONCLUSIONS

Antinuclear antibodies seem to be associated with more severe disease activity in NMOSD patients.

Neuromyelitis optica: a pilot study of clinical presentation and status of serological biomarker AQP4 among patients admitted to a tertiary centre in NCNS, Sudan

Background

Neuromyelitis optica (NMO) is a demyelinating disease primarily affecting the optic nerves and spinal cord. It is distinguished from other demyelinating conditions by the presence of AQP4-IgG and serum aquaporin 4 (AQP4), found mainly in the blood–brain barrier. This descriptive study was conducted from January 2015 to June 2018 at the National Center for Neurological Sciences (NCNS) in Khartoum, Sudan. All participants were Sudanese patients diagnosed with NMO. In our study the selection of cases was based on Dean Wingerchuk diagnostic criteria (2006), which states that the diagnosis of NMO should meet two absolute criteria and two supportive criteria. The absolute criteria are myelitis and optic neuritis, whereas supportive criteria include radiological findings obtained from brain and spinal cord MRI. Furthermore, AQP4-IgG levels were measured from cerebrospinal fluid (CSF) and serum using immunofluorescence. Data were collected by a pre-designed questionnaire and analyzed using SPSS version 17. A p value < 0.05 was considered statistically significant.

Results

A total of 31 patients were enrolled in this study [6 male (19.4%) and 25 female (80.6%)]. The mean age was 38 ± 12.8 years. Motor and visual difficulties were the initial symptoms and occurred in 21 (67.7%) and 10 (32.3%) patients, respectively. Fundoscopy confirmed optic atrophy in 22 (71.0%) patients. The course of the disease revealed one relapse in 21 patients (67.7%). Seropositive AQP4-IgG were seen in 23 patients (79.31%). There was a significant correlation between AQP4 and response to treatment (p ≤ 0.038). The correlation between serum AQP4-IgG, showed that, complete improvement was detected in 2 patients (6.9%) one of them was positive and the other was negative, 20 (69.0%) patients presented with some disability, among them 18 (62.1%) were positive and 2 (6.9%) were negative, while 7 patients showed no improvement (24.1%) 4 out of them were positive (13.8%) and 3 were negative (10.3%).

Conclusion

At the initial presentation of NMO, longitudinal myelitis was observed more frequently than optic neuritis. More than two third of the patients showed strong seropositivity for serum AQP4. Most seropositive patients showed a good response to treatment but with residual disabilities.

Blood pressure and body fat percent in women with NMOSD

BACKGROUND

Hypertension is a prevalent and impactful comorbid condition among patients with multiple sclerosis (MS). High level of body mass index (BMI) is associated with the risk and poor outcomes of neuromyelitis optica spectrum disorder (NMOSD) in women. However, the clinical implication of blood pressure (BP) and body fat percent (BF%) based on the Clínica Universidad de Navarra-Body Adiposity Estimator (CUN-BAE) in NMOSD has not been investigated thus far.

METHODS

Case data were collected from 47 NMOSD and 28 MS patients at acute phase, 21 NMOSD and 25 MS patients at stable phase, and 68 age- and sex-matched HCs. Four BP measures including systolic BP (SBP), diastolic BP (DBP), pulse pressure (PP), and mean arterial pressure (MAP); BMI; and BF% between NMOSD, MS, and healthy controls were determined.

RESULTS

Comparing NMOSD patients with MS patients, the former have significantly higher SBP (p < 0.001), DBP (p < 0.001), PP (p < 0.001), MAP (p < 0.001), BF% (p = 0.001), and BMI (p < 0.001) levels at acute phase after adjusting for age. Acute myelitis (OR 3.719, 95% CI 1.110-12.453) is more likely to occur in NMOSD patients with high BF% (≥30%) at acute phase. BF% was negatively correlated with 1/AQP4 titer in NMOSD at acute phase (r = -0.522, p = 0.004).

CONCLUSIONS

Women with NMOSD are probably more prone to have an increased BP and fat mass compared to MS.

The Cerebrospinal Fluid in Multiple Sclerosis

Investigation of cerebrospinal fluid (CSF) in the diagnostic work-up in suspected multiple sclerosis (MS) patients has regained attention in the latest version of the diagnostic criteria due to its good diagnostic accuracy and increasing issues with misdiagnosis of MS based on over interpretation of neuroimaging results. The hallmark of MS-specific changes in CSF is the detection of oligoclonal bands (OCB) which occur in the vast majority of MS patients. Lack of OCB has a very high negative predictive value indicating a red flag during the diagnostic work-up, and alternative diagnoses should be considered in such patients. Additional molecules of CSF can help to support the diagnosis of MS, improve the differential diagnosis of MS subtypes and predict the course of the disease, thus selecting the optimal therapy for each patient.

A prospective case-control study comparing optical coherence tomography characteristics in neuromyelitis optica spectrum disorder- optic neuritis and idiopathic optic neuritis

Background

Neuromyelitis optica spectrum disorder-optic neuritis (NMOSD-ON) can now be distinguished from other types of ON as a specific disease by the Aquaporin-4 antibody (AQP4-Ab) test. NMOSD-ON can cause severe retinal nerve fiber layer (RNFL) damage. The optical coherence tomography (OCT) characteristics between NMOSD- ON and idiopathic optic neuritis (IDON) were seldom studied in Asians.

Methods

This prospective case-control study involved 152 eyes from 143 optic neuritis (ON) patients. All the patients were divided into either the NMOSD-ON group or the IDON group based on the AQP4-Ab test. The retinal nerve fiber layer thickness (RNFLT), retinal thickness (RT), and choroidal thickness (CT) were measured by spectral-domain OCT and compared to the 60 age- and gender-matched healthy controls. The association between RNFLT and best corrected visual acuity (BCVA) was examined.

Results

The RNFLT was significantly thinner in all ON patients than in healthy controls, while NMOSD-ON eyes were significantly more affected than IDON eyes in all quadrants (p < 0.01). NMOSD-ON patients had stronger visual function impairment than IDON patients (p < 0.01). RNFLT was related to BCVA in both the NMOSD-ON and IDON groups. Microcystic macular edema (MME) was identified in 28 patients (19.58%) and in 29 of 152 eyes (19.08%), including 20 of 40 eyes (50%) previously affected by ON. MME was more common in patients with NMOSD-ON (32.2%) than in those with IDON (10.75%) (p = 0.001).

Conclusions

The NMOSD-ON group had more pronounced RNFLT thinning and visual function impairment than the IDON group. MME prevalence was higher in NMOSD-ON and was associated with higher frequency of clinical relapses.

Autoantibodies Associated With Connective Tissue Diseases: What Meaning for Clinicians?

Connective tissue diseases (CTDs) such as systemic lupus erythematosus, systemic sclerosis, myositis, Sjögren's syndrome, and rheumatoid arthritis are systemic diseases which are often associated with a challenge in diagnosis. Autoantibodies (AAbs) can be detected in these diseases and help clinicians in their diagnosis. Actually, pathophysiology of these diseases is associated with the presence of antinuclear antibodies. In the last decades, many new antibodies were discovered, but their implication in pathogenesis of CTDs remains unclear. Furthermore, the classification of these AAbs is nowadays misused, as their targets can be localized outside of the nuclear compartment. Interestingly, in most cases, each antibody is associated with a specific phenotype in CTDs and therefore help in better defining either the disease subtypes or diseases activity and outcome. Because of recent progresses in their detection and in the comprehension of their pathogenesis implication in CTD-associated antibodies, clinicians should pay attention to the presence of these different AAbs to improve patient's management. In this review, we propose to focus on the different phenotypes and features associated with each autoantibody used in clinical practice in those CTDs.

Neuromyelitis Optica Spectrum Disorders

PURPOSE OF REVIEW

This article provides a practical approach for providers caring for patients with neuromyelitis optica (NMO) spectrum disorders. Clinical and imaging features, diagnostic criteria, treatment of acute exacerbations, chronic preventive therapy, and symptom management in NMO spectrum disorders are discussed.

RECENT FINDINGS

The rapid pace of research in NMO spectrum disorders has led to many recent advances. A broader understanding of the clinical spectrum of the disease as well as improvements in anti-aquaporin-4 antibody assays have led to recent revision of the diagnostic criteria. Several recent studies have expanded the knowledge base regarding the efficacy and safety of current therapies for NMO spectrum disorders.

SUMMARY

An NMO spectrum disorder is an inflammatory disorder affecting the central nervous system, previously thought to be closely related to multiple sclerosis but more recently demonstrated to represent a distinct clinical and pathophysiologic entity. As NMO spectrum disorders carry significant morbidity and, at times, mortality, prompt and accurate diagnosis followed by swift initiation of therapy for both treatment of acute exacerbations and prevention of further relapses is critical. This article provides a practical approach to the diagnosis and management of NMO spectrum disorders.

Elevated cerebrospinal fluid uric acid during relapse of neuromyelitis optica spectrum disorders

INTRODUCTION

Previous studies have shown that serum uric acid (UA) modulates outcomes of neurological diseases, although little is known about cerebrospinal fluid (CSF) UA levels in neuromyelitis optica spectrum disorders (NMOSDs).

METHODS

Cerebrospinal fluid and serum UA levels were measured in samples from 68 patients, including NMOSDs during relapse (n = 38) and controls with noninflammatory and non-neurodegenerative diseases (CTLs, n = 30). Correlation analysis was performed between CSF UA and clinical characteristics, serum UA, and blood-brain barrier integrity in NMOSDs.

RESULTS

Cerebrospinal fluid UA levels in NMOSDs were significantly higher than in CTLs (p = .002), while serum UA differences between NMOSDs and CTLs were not statistically significant. In NMOSDs, CSF UA levels were significantly higher in patients with an impaired blood-brain barrier than in patients with an intact one (p < .001), and significantly higher in longer disease duration than in shorter disease duration patients (p = .002). CSF UA levels were also significantly higher in active patients upon MRI than in inactive patients (p < .001), and significantly higher in patients with brain lesions than without brain lesions (p = .024). CSF UA was significantly associated with the serum UA levels (r = .454, p = .002), disease duration (r = .383, p = .018), and blood-brain barrier index (r = .805, p < .001), but did not correlate with age, gender, annualized relapse rate, duration, or severity of NMOSD. Multiple regression analysis demonstrated that CSF UA was independent of the blood-brain barrier index (β = .765, p < .001) and serum UA levels (β = .01, p = .019) in NMOSDs.

CONCLUSIONS

Cerebrospinal fluid UA levels were elevated in NMOSD patients during relapse, and were likely modified by serum UA levels and blood-brain barrier integrity.

Aquaporin-4 antibody in neuromyelitis optica: re-testing study in a large population from China

BACKGROUND

Aquaporin-4 (AQP4) antibody sero-positivity is critically important in neuromyelitis optica (NMO). However, the sensitivity of different assays is highly variable. Repeating detection with a highly sensitive assay in a large population is necessary in the case of so-called negative NMO.

METHODS

Retrospective analysis where AQP4 antibodies were detected by commercial cell-based assay (CBA), in-house M23-CBA and in-house M1-CBA.

RESULTS

Of the 1011 serum samples, 206 (20.4%) were sero-positive by primary commercial CBA. In the retest, all 206 participants positive by primary commercial CBA also yielded positive results by in-house M23-CBA and the second commercial CBA again, but only 124 positive in in-house M1-CBA. Among the 805 participants negative by primary commercial CBA, 71 participants were positive for in-house M23-CBA, of which 20 participants were positive for the second commercial CBA, and none were positive by in-house M1-CBA. Of the 171 cerebral spinal fluid samples, 75 (43.9%) were positive by primary commercial CBA. All 75 participants positive by primary commercial CBA also yielded positive results by in-house M23-CBA and the second commercial CBA. Forty-nine (65.3%) of these 75 participants were positive by in-house M1-CBA. Among the 96 participants negative by primary commercial CBA, 15 participants were positive for in-house M23-CBA and none were positive by in-house M1-CBA and the second commercial CBA.

CONCLUSIONS

Different AQP4 isoforms in CBA result in different detection effects, and in-house M23-CBA is the most sensitive method. Some AQP4 antibody-negative NMO may be subject to diagnostic uncertainty due to limitations of the assays.

Transverse Myelitis and Neuromyelitis Optica Spectrum Disorders

Transverse myelitis is defined as inflammation of the spinal cord, named because of its typical clinical presentation with bandlike symptoms of altered sensation or pain in a horizontal fashion-at a specific dermatome level. Radiographic patterns might vary but the idiopathic form is more frequent to present as involvement of 3-4 vertebral segments and both sides of the cord. It is now recognized that there are numerous other causes as well as the idiopathic type, with often atypical features and geographic variation. There is also increasing recognition of other forms of myelitis, particularly the longitudinally extensive manifestation with involvement of 3 or more vertebral segments. Neuromyelitis optica, one of these subtypes can be diagnosed by means of an antibody assessment. The picture is more complicated with the expansion of the description to involve neuromyelitis optica spectrum disorders, new antibodies such as myelin oligodendrocyte glycoprotein and the inclusion of an antibody-negative variant. This article describes the different entities of transverse myelitis, with a particular focus on neuromyelitis optica spectrum disorders.

Dynamic change in magnetic resonance imaging of patients with neuromyelitis optica

OBJECTIVE

To analyze changes in magnetic resonance imaging (MRI) of spinal cord lesions in neuromyelitis optica (NMO) and the correlation between segmental length of spinal cord lesions and expanded disability status scale (EDSS) scores.

METHODS

Twenty-five patients with confirmed NMO were examined from the Second Affiliated Hospital of Guangzhou Medical University, China. The information collected included their treatment, MRI, laboratory tests, and EDSS scores at different stages.

RESULTS

All cases exhibited spinal cord lesions, with 23 (92%) having longitudinally extensive transverse myelitis (extending ≥3 vertebral segments). There was a positive correlation between segmental length of spinal cord lesions and EDSS scores: during the acute phase, r = 0.430 (P = 0.032); during remission, r = 0.605 (P = 0.002). Enlarged spinal cord lesions and swelling were found in 18 cases (72%) during the acute phase, and 4 cases (16%, P = 0.000) after 6 months of treatment. Lesion enhancements were found in 17 cases (68%) during the acute phase, and 8 cases (32%, P = 0.023) after 6 months of treatment. Leptomeningeal enhancement was found in three cases during the acute phase, which disappeared after treatment. Atrophy of spinal cord lesions occurred in two cases. Change in lesions was statistically significant (P = 0.006) after 12 months of treatment.

CONCLUSION

Positive correlation was found between segmental length of spinal cord lesions and EDSS scores, which was more significant during remission. After 6 months of regular treatment, restorative changes compared with the acute phase were found by MRI.

Molecular biomarkers in cerebrospinal fluid of multiple sclerosis patients

Multiple sclerosis (MS) is a chronic immune-mediated disease of the central nervous system, usually occurring in young adults and leading to disability. Despite the progress in technology and intensive research work of the last years, diagnosing MS can still be challenging. A heterogenic and complex pathophysiology with various types of disease courses makes MS unique for each patient. There is an urgent need to identify markers facilitating rapid and accurate diagnosis and prognostic assessments with regard to optimal therapy for each MS patient. Cerebrospinal fluid (CSF) is an outstanding source of specific markers related to MS pathology. Molecules reflecting specific pathological processes, such as inflammation, cellular damage, and loss of blood-brain-barrier integrity, are detectable in CSF. Clinically used biomarkers of CSF are oligoclonal bands, IgG-index, measles-rubella-zoster-reaction, anti-aquaporin 4 antibodies, and antibodies against John Cunningham virus. Many other potential biomarkers have been proposed in recent years. In this review we examine the current scientific knowledge on CSF molecular markers that could guide diagnosis and discrimination of different MS forms, support treatment decisions, or be helpful in monitoring and predicting disease progression, therapy response, and complications such as opportunistic infections.

Syndrome of inappropriate antidiuretic hormone secretion in patients with aquaporin-4 antibody

The objective of this study was to analyze the frequency of syndrome of inappropriate antidiuretic hormone secretion (SIADH) in patients with positive aquaporin-4 (AQP4) antibodies and evaluate the relationship between SIADH and hypothalamic lesions in patients with NMO and NMO spectrum disorder (NMOSD). AQP4 antibodies were tested by an indirect immunofluorescence assay employing HEK-293 cells transfected with recombinant human AQP4. Clinical data of patients were analyzed retrospectively. In total, 192 patients with AQP4 antibodies were certified, of which 41 patients (21.4 %) were included in the present study. Six patients (14.6 %, 6/41) met the criteria of SIADH, of which hyponatremia was mild in one patient, and severe in five. Five patients experienced confusion or decreased consciousness. Four patients were diagnosed with NMO and two were diagnosed with recurrent optic neuritis. Magnetic resonance imaging showed 11 of 41 patients (26.8 %) had hypothalamic lesions. All patients with SIADH had hypothalamic abnormalities. Hyponatremia resolved in all patients after intravenous methylprednisolone and intravenous immunoglobulin therapy. SIADH is not rare in patients with NMO/NMOSD, especially in patients with lesions close to the hypothalamus.

Serum anticardiolipin antibodies in patients with neuromyelitis optica spectrum disorder

The presence of anticardiolipin antibodies (ACLA) in multiple sclerosis (MS) patients has been reported, but there are some debates on the relationship between ACLA and MS. We assessed the clinical features of neuromyelitis optica spectrum disorders (NMOSD) patients with ACLA. A consecutive cohort of 480 subjects with NMOSD (n = 70), MS (n = 90) and control (n = 220) were analysed retrospectively. Patients' serum was tested by a dot-immunogold filtration assay for the presence of ACLA-IgG, IgM and IgA antibodies. In MS patients, 5 (5.6 %) of the 90 patients showed ACLA-IgG reactivity in the serum. In NMOSD patients, 32 (45.7 %) of the 70 patients showed ACLA reactivity in the serum, among which ACLA-IgG seropositivity was 45.7 % (32/70), ACLA-IgG + IgM seropositivity was 8.6 % (6/70), and ACLA-IgG + IgA seropositivity was 4.3 % (3/70). NMOSD patients were higher in ACLA-IgG (p < 0.0001) and ACLA-IgG + IgM (p = 0.006) than the MS patients. NMOSD patients had higher ACLA-IgG than the control patients (p < 0.0001). In comparison with the controls, the MS patients were lower in ACLA for IgG (p = 0.014) and IgM (p = 0.004). Seropositive ACLA patients increased in age (p = 0.013) and had higher D-dimer levels (DD) (p = 0.002) than the seronegative NMOSD patients. Furthermore, positive ACLA-IgG + IgM patients were increased in age (p = 0.001), had higher baseline EDSS (p = 0.001), antithrombin III activity (p = 0.04), and DD levels (p = 0.005) than the pure positive ACLA-IgG NMOSD patients. Patients with NMOSD had more occurrences of ACLA than patients with MS. NMOSD patients with positive ACLA-IgG + IgM had a worse outcome that may be associated with elder age and abnormal coagulation parameters in blood.

Serum thyroid-stimulating hormone and anti-thyroglobulin antibody are independently associated with lesions in spinal cord in central nervous system demyelinating diseases

Transverse myelitis (TM) is associated with neuromyelitis optica (NMO) and multiple sclerosis (MS). Early recognition of useful parameters may be helpful to distinguish their difference. This retrospective study analyzed thyroid parameters from 243 serum samples (relapse = 128; remission = 115) of 178 patients with demyelinating diseases (NMO, n = 25; TM, n = 48; MS, n = 105). The relationship between thyroid and clinical parameters was analyzed. Patients with NMO and TM had a higher frequency of abnormal thyroid-stimulating hormone (TSH), anti-thyroglobulin antibodies (TG-Ab), and antithyroid peroxidase antibody (TPO-Ab) than MS patients (p<0.05). The level of TSH and TG-Ab returned to normal levels after administration of high-dose intravenous methylprednisolone (p<0.05). In 96 patients (NMO, n = 19; TM, n = 25; MS, n = 52) without treatment, serum levels of TSH, TG-Ab and TPO-Ab were significantly different between patients with and without myelitis (p<0.01). Patients positive for aquaporin-4 (AQP4) antibodies showed higher abnormalities of TSH (p = 0.001), TG-Ab (p = 0.004) and TPO-Ab (p<0.0001) levels than AQP4 antibodies negative patients. Logistic regression analyses revealed independent relationships between TSH (odds ratio [OR]  = 33.994; p<0.0001), TG-Ab (OR = 7.703; p = 0.017) and myelitis occurrence in 96 patients at the active stage. In 52 MS patients experiencing their first attack, MS patients with myelitis were associated with TSH abnormalities (OR = 42.778; p<0.0001). This study showed increased abnormalities of thyroid parameters in patients with NMO and TM than in MS patients. MS patients with myelitis also had greater TSH abnormality than in MS patients without myelitis. Abnormal TSH and TG-Ab were independently associated with myelitis occurrence in central nervous system demyelinating disorders.

Aquaporin-4 antibodies (NMO-IgG) as a serological marker of neuromyelitis optica: a critical review of the literature

Antibodies to aquaporin-4 (called NMO-IgG or AQP4-Ab) constitute a sensitive and highly specific serum marker of neuromyelitis optica (NMO) that can facilitate the differential diagnosis of NMO and classic multiple sclerosis. NMO-IgG/AQP4-Ab seropositive status has also important prognostic and therapeutic implications in patients with isolated longitudinally extensive myelitis (LETM) or optic neuritis (ON). In this article, we comprehensively review and critically appraise the existing literature on NMO-IgG/AQP4-Ab testing. All available immunoassays-including tissue-based (IHC), cell-based (ICC, FACS) and protein-based (RIPA, FIPA, ELISA, Western blotting) assays-and their differential advantages and disadvantages are discussed. Estimates for sensitivity, specificity, and positive and negative likelihood ratios are calculated for all published studies and accuracies of the various immunoassay techniques compared. Subgroup analyses are provided for NMO, LETM and ON, for relapsing vs. monophasic disease, and for various control groups (eg, MS vs. other controls). Numerous aspects of NMO-IgG/AQP4-Ab testing relevant for clinicians (eg, impact of antibody titers and longitudinal testing, indications for repeat testing, relevance of CSF testing and subclass analysis, NMO-IgG/AQP4-Ab in patients with rheumatic diseases) as well as technical aspects (eg, AQP4-M1 vs. AQP4-M23-based assays, intact AQP4 vs. peptide substrates, effect of storage conditions and freeze/thaw cycles) and pitfalls are discussed. Finally, recommendations for the clinical application of NMO-IgG/AQP4-Ab serology are given.

Antineutrophil cytoplasmic antibodies in patients with idiopathic inflammatory-demyelinating diseases

OBJECTIVE

We assessed the clinical significance of antineutrophil cytoplasm antibodies (ANCA) in patients with idiopathic inflammatory-demyelinating disease (IIDD).

METHODS

A consecutive cohort of 269 subjects with IIDD and 595 controls was analyzed retrospectively.

RESULTS

Among all subjects, ANCA positivity rates were low [9.5% in a perinuclear pattern (pANCA) and 2.3% in a cytoplasmic pattern (cANCA)]. One of the 117 patients with multiple sclerosis (MS) had cANCA and 2 had pANCA. Ten patients with neuromyelitis optica (NMO; 13.9%) had pANCA and 3 (4.2%) had cANCA. Four patients with recurrent longitudinal extensive transverse myelitis (RLETM; 19.0%) had pANCA and 1 (4.8%) had cANCA. In monophasic TM, 22.9% were pANCA seropositive. Among patients with brainstem syndromes, 14.3% were pANCA seropositive. Patients with NMO, RLETM or monophasic TM had higher pANCA levels than patients with MS. There was a positive association between spinal cord (SC) lesions and ANCA, and especially between longitudinal extensive transverse myelitis and ANCA. Among anti-aquaporin 4 antibody-positive patients, ANCA-positive patients (n = 16) were older and had higher Expanded Disability Status Scale scores, more antinuclear antibodies, longer SC lesions and fewer brain abnormalities than the ANCA-negative patients (n = 68). In the NMO subgroup, ANCA-positive patients were older and had more antinuclear antibodies and longer SC lesions than ANCA-negative patients.

CONCLUSION

Among the IIDDs, we found a higher occurrence of ANCA in patients with NMO spectrum disorders than in patients with MS. Therefore, ANCA is another interesting marker of autoimmunity in IIDD patients, especially those with anti-aquaporin 4 antibody.

Aquaporin-4 antibodies (NMO-IgG) as a serological marker of neuromyelitis optica: a critical review of the literature

Antibodies to aquaporin-4 (called NMO-IgG or AQP4-Ab) constitute a sensitive and highly specific serum marker of neuromyelitis optica (NMO) that can facilitate the differential diagnosis of NMO and classic multiple sclerosis. NMO-IgG/AQP4-Ab seropositive status has also important prognostic and therapeutic implications in patients with isolated longitudinally extensive myelitis (LETM) or optic neuritis (ON). In this article, we comprehensively review and critically appraise the existing literature on NMO-IgG/AQP4-Ab testing. All available immunoassays-including tissue-based (IHC), cell-based (ICC, FACS) and protein-based (RIPA, FIPA, ELISA, Western blotting) assays-and their differential advantages and disadvantages are discussed. Estimates for sensitivity, specificity, and positive and negative likelihood ratios are calculated for all published studies and accuracies of the various immunoassay techniques compared. Subgroup analyses are provided for NMO, LETM and ON, for relapsing vs. monophasic disease, and for various control groups (eg, MS vs. other controls). Numerous aspects of NMO-IgG/AQP4-Ab testing relevant for clinicians (eg, impact of antibody titers and longitudinal testing, indications for repeat testing, relevance of CSF testing and subclass analysis, NMO-IgG/AQP4-Ab in patients with rheumatic diseases) as well as technical aspects (eg, AQP4-M1 vs. AQP4-M23-based assays, intact AQP4 vs. peptide substrates, effect of storage conditions and freeze/thaw cycles) and pitfalls are discussed. Finally, recommendations for the clinical application of NMO-IgG/AQP4-Ab serology are given.

Antibodies target microvessels in neuromyelitis optica and multiple sclerosis patients

OBJECTIVE

This study investigated the presence of serum antibodies targeting microvessels in Chinese patients with multiple sclerosis (MS) and neuromyelitis optica (NMO).

METHODS

Serum samples were collected from 50 patients with NMO, 10 with longitudinally extensive transverse myelitis (LETM), 4 with recurrent optic neuritis, 42 with MS and 27 controls. Serum antibodies binding to microvessels were measured by indirect immunofluorescence (IIF) assay of tissue sections from the brain, stomach and pancreas, and human umbilical vein endothelial cells (HUVEC). Aquaporin-4 (AQP4) antibodies were detected using a cell-based assay.

RESULTS

Indirect immunofluorescence assay of tissue sections from 42 samples (30.4%, 42/138) were positive for microvessel antibodies, where microvessel antibody positivity was 38% (19/50) in patients with NMO, 57.1% (8/14) in high-risk NMO (hrNMO), 26.2% (11/42) in MS, and 14.8% (4/27) in controls. Based on HUVEC analysis, 14 patients with NMO (28%, 14/50), 5 with hrNMO (35.7%, 5/14), 15 with MS (35.7%, 15/42), and 5 controls (18.5%, 5/27) had (AECA). Sixteen patients (32%, 16/50) with NMO, four with hrNMO (28.6%, 4/14), two with MS (4·8%, 2/42), and 0% of controls were positive for antinuclear antibodies (ANA). In MS patients, seropositive AECA MS patients had higher numbers of relapse events and increased spinal lesions than seronegative MS patients (P < 0.05).

CONCLUSIONS

Serum microvessel antibodies were present in patients with NMO and MS and the role of microvessel antibodies in diseases may be heterogeneous. This study suggests that AECA may have some significance in MS patients.

Helicobacter pylori infection in Neuromyelitis Optica and Multiple Sclerosis

OBJECTIVE

To determine the Helicobacter pylori infection status in patients with multiple sclerosis (MS) and neuromyelitis optica (NMO) spectrum.

METHODS

H. pylori infection was certified by indirect immunofluorescence assay. Aquaporin-4 (AQP4) antibody was detected by cell-based assay. H. pylori seroprevalence was measured in 118 patients with NMO (n = 52), high-risk NMO (hrNMO, longitudinally extensive transverse myelitis, n = 17 and recurrent optic neuritis, n = 7), MS (n = 42) and healthy controls (n = 27). Logistic regression analysis was used to determine associations between H. pylori infection and NMO and MS.

RESULTS

H. pylori antibodies were present in 119 serum samples (82.1%, 119/145), with antibody positivity in 90.4% (47/52) of the patients with NMO, 95.8% (23/24) of the patients with hrNMO, 73.8% (31/42) of the patients with MS and 59.3% (16/27) of the controls. NMO spectrum patients had greater positivity for H. pylori than MS patients (p < 0.05) and controls (p < 0.05). The frequency of H. pylori seropositivity did not significantly differ between MS patients and controls (p = 0.726). H. pylori seropositivity was significantly higher in AQP4 antibody-positive patients (54/58, 93.1%; p = 0.038) than in AQP4 antibody-negative patients (48/60, 80%). Logistic regression analysis showed that H. pylori seropositivity was significantly associated with hrNMO [odds ratio (OR) = 9.311, p = 0.005] or hrNMO + NMO (OR = 6.350, p = 0.028).

CONCLUSION

H. pylori infection was present in most Chinese patients with NMO and hrNMO, and may be a risk factor for the NMO spectrum.

Notable increased cerebrospinal fluid levels of soluble interleukin-6 receptors in neuromyelitis optica

BACKGROUND

IL-6 is a proinflammatory cytokine which is involved in the maintenance of the humoral response in various autoimmune disorders. Cerebrospinal fluid (CSF) IL-6 has shown to be increased in neuromyelitis optica (NMO). The soluble form of IL-6 receptor (sIL-6R), which links to IL-6, can activate biological responses in cells. Whether or not sIL-6R is altered in NMO has not been clarified.

OBJECTIVE

To measure CSF IL-6 and sIL-6R in NMO and multiple sclerosis (MS) patients, and investigate whether IL-6 and sIL-6R have possible uses as sensitive biomarkers for diseases activity.

METHODS

CSF concentrations of IL-6 and sIL-6R were measured by an ELISA in NMO (n = 22) and MS (n = 18) patients, as well as control subjects (n = 14).

RESULTS

The concentration of IL-6 levels were higher in NMO compared to MS (p = 0.032) and the controls (p = 0.023). The levels of sIL-6R were also higher in NMO compared to MS (p = 0.002) and the controls (p < 0.001). CSF sIL-6R was associated with an Expanded Disability Status Scale score in NMO (p = 0.005) but not in MS (p = 0.891). In the MS subgroup, sIL-6R concentrations were associated with CSF white blood cells (p = 0.034).

CONCLUSIONS

Our study revealed that CSF sIL-6R was increased in NMO patients, and correlated with clinical presentations.