First manifestation of AQP4-IgG-positive neuromyelitis optica spectrum disorder following the COVID-19 mRNA vaccine BNT162b2.

BNT162b2 is one of the effective COVID-19 vaccines. However, some researchers have also reported some neurological adverse events after the vaccination. Here, we present a case of a 52-year-old female who developed aquaporin (AQP) 4-IgG-positive neuromyelitis optica spectrum disorder (NMOSD) 14 days after the first dose of BNT162b2. She experienced the neck pain, weakness of the left arm and leg, numbness of the left hand, and impaired temperature sensation of the right leg. MRI showed T2WI hyperintense lesions in the area postrema and cervical spinal cord ranging from C1 to C6 level and Gd-enhanced lesions from C3 to C5 level; especially left lateral column was predominantly enhanced. Cell-based assays showed anti-AQP4 antibody (AQP4Ab) was positive. We diagnosed AQP4-IgG-positive NMOSD. After high-dose glucocorticoid therapy, she is showing improved symptoms. The present case was characterized by the findings that a Gd-enhanced lesion in the cervical cord localized dominantly at the left lateral column, consistent with the side of the shoulder where the vaccine was injected. Many studies suggested that AQP4-IgG-positive NMOSD development has multistep mechanisms following the blood-brain barrier (BBB) breakdown. We suspected that immune responses following vaccination lead to BBB disruptions. Through the limitedly damaged BBB, the plasma cells producing AQP4Abs might be recruited to CNS, and AQP4Abs might bind to the cervical cord and the area postrema. A population-based study revealed that neurological events following COVID-19 vaccination were less likely to be observed than COVID-19 infectious symptoms. Considering rare adverse events, clinicians need to observe any changes in patient condition.

Multiple sclerosis (MS) and neuromyelitis optica spectrum disorder (NMOSD) following COVID-19 vaccines: A systematic review.

BACKGROUND: The global COVID-19 pandemic began in March 2019, and given the number of casualties and adverse effects on the economy, society, and all aspects of the health system, efforts have been made to develop vaccines from the beginning of the pandemic. Numerous vaccines against COVID-19 infection have been developed in several technologies and have spread rapidly. There have been reported multiple complications of the COVID-19 vaccines as with other vaccines. A number of studies have reported multiple sclerosis (MS ) and neuromyelitis optica spectrum disorder (NMOSD) as complications of COVID-19 vaccines. METHODS: First, we found 954 studies from 4 databases (PubMed, Embase, Scopus, and Web of Science) from inception to March 1st, 2022. Next, duplicate articles were eliminated, and 476 studies remained. Then 412 studies were removed according to inclusion and exclusion criteria. After obtaining the full text of 64 articles, 12 studies were selected finally. RESULTS: The data were extracted from included studies in a table. Our data includes demographic data, comorbidities, vaccines information and side effects, NMOSD and MS symptoms, laboratory and cerebrospinal fluid (CSF) findings, magnetic resonance imaging (MRI) results, treatment, and outcome of all cases. CONCLUSION: MS and NMOSD are two neuroinflammatory disorders that arise in the CNS. Cases of MS and NMOSD have been reported following COVID-19 vaccination. Nevertheless, more studies with more subjects are needed to assess any possible relationship between the COVID-19 vaccine and central nervous system demyelination.

Severe disease exacerbation after mRNA COVID-19 vaccination unmasks suspected multiple sclerosis as neuromyelitis optica spectrum disorder: a case report.

BACKGROUND: Since the beginning of the COVID-19 pandemic and development of new vaccines, the issue of post-vaccination exacerbation or manifestation of demyelinating central nervous system (CNS) disorders has gained increasing attention. CASE PRESENTATION: We present a case of a 68-year-old woman previously diagnosed with multiple sclerosis (MS) since the 1980s who suffered a rapidly progressive severe sensorimotor paraparesis with loss of bladder and bowel control due to an acute longitudinal extensive transverse myelitis (LETM) after immunization with the mRNA Pfizer-BioNTech COVID-19 vaccine. Detection of Aquaporin-4-antibodies (AQP4) in both serum and CSF led to diagnosis of AQP4-antibody positive neuromyelitis optica spectrum disorder (NMOSD). Treatment with intravenous corticosteroids and plasmapheresis led to a slight improvement of the patient's symptoms. CONCLUSIONS: Pathogenic mechanisms of post-vaccination occurrence of NMOSD are still unknown. However, cases like this should make aware of rare neurological disorders manifesting after vaccination and potentially contribute to improvement of management of vaccinating patients with inflammatory CNS disorders in the future. So far two cases of AQP4-antibody positive NMOSD have been reported in association with viral vector COVID-19 vaccines. To our knowledge, we report the first case of AQP4-antibody positive NMOSD after immunization with an mRNA COVID-19-vaccine.

COVID-19 associated with encephalomyeloradiculitis and positive anti-aquaporin-4 antibodies: Cause or coincidence?

Neurologic complications are being recognized as important outcomes of coronavirus disease 2019 (COVID-19). Pathogenesis is varied and incompletely understood, and may include neuroinvasion, indirect post-infectious neuroinflammation, and cerebrovascular pathologies. We present a case of COVID-19-related encephalomyeloradiculitis with clinical and magnetic resonance imaging characteristics of neuromyelitis optica spectrum disorders that was associated with anti-aquaporin-4 antibodies. Our case suggests post-infectious autoimmunity as a mechanism in at least a subset of patients with COVID-19-related neurologic disease.

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.

Clinical features of transverse myelitis associated with systemic lupus erythematosus.

OBJECTIVE: This study aimed to identify the clinical characteristics and prognostic factors of systemic lupus erythematosus with transverse myelitis (SLE-TM) in a relatively large patient series. METHODS: This retrospective study considered 45 SLE-TM individuals treated as inpatients and outpatients at Peking Union Medical College Hospital between 1993 and 2018. SLE-TM patients were compared with 180 controls, and SLE-TM patients with neuromyelitis optica spectrum disorder (NMOSD) were compared to those without NMOSD. RESULTS: Compared to controls, the SLE-TM group frequently had a fever and had a significantly higher positive rate of anticardiolipin and lupus anticoagulant. Among the 45 patients, 22 met the NMOSD criteria. Compared to non-NMOSD patients, NMOSD patients had a lower incidence of rash (p = 0.023), serositis (p = 0.042) and renal disorder (p = 0.073); a lower prevalence of decreased complement (p = 0.083); and lower rates of positive anti-dsDNA (p = 0.074) and anti-Sm (p = 0.042). Among 22 SLE-TM patients with NMOSD, 18 underwent aquaporin 4 antibody testing, with 11 showing positive results. Out of the 45 patients, 39 were given methylprednisolone pulse treatment. After treatment, 32 patients had lower-limb muscle strength recovery (recovered group), whereas 13 had no change and persistent severe neurological deficits (non-recovered group). Compared to the recovered group, the non-recovered group were younger (p = 0.002), had a higher likelihood of having a fever (p = 0.020), initial severe myelitis (p < 0.001), long spinal segment involvement (p = 0.017) and higher C-reactive protein levels (p = 0.020). Methylprednisolone pulse given within two weeks of onset was more frequent in the recovered group than in the non-recovered group (p = 0.082). CONCLUSIONS: Disease characteristics differed between SLE-TM patients with and without NMOSD. SLE and NMOSD tended to be co-morbidities. Initial severe neurological impairment, extensive spinal cord lesions, hyper-inflammation and delayed steroid impulse treatment could be predictors of poor outcome for SLE-TM.

Aquaporin-4 antibody positive neuromyelitis optica spectrum disorder subsequent to rhabdomyolysis: a case report and literature review.

Rhabdomyolysis could be caused by various mechanisms including autoimmune reaction. Here, we reported a case of 76-year-old-woman diagnosed with aquaporin-4 (AQP4) IgG positive neuromyelitis optica spectrum disorder (NMOSD) following rhabdomyolysis. After a review of literature, we propose that physical injury of skeletal muscle cells may lead to the production of AQP4 IgG and this AQP4 IgG might further decrease in the stability of skeletal muscle cells creating a positive feedback loop. HyperCKemia might be an inducement of NMOSD.

[NEUROMYELITIS OPTICA SPECTRUM DISORDERS: A REVIEW OF MODERN DATA AND CLINICAL CASE REPORTS].

The article presents current data on the issues of etiopathogenesis, pathomorphology, clinical course, diagnostic and treatment management of neuromyelitis optica spectrum disorders from the group of autoimmune demyelinating diseases. The data of own clinical cases are given.

Etiologic spectrum and prognosis in noncompressive acute transverse myelopathies: An experience of 80 patients at a tertiary care facility.

INTRODUCTION: We evaluated the spectrum of acquired demyelinating and inflammatory disorders in patients presenting with an acute transverse myelopathy. We also studied differences between an acute idiopathic transverse myelitis and myelitis resulting from other etiologies. MATERIALS AND METHODS: Eighty consecutive patients with acute transverse myelopathy were included. At inclusion, clinical profile, serum and cerebrospinal fluid parameters, brain and spinal cord magnetic resonance imaging, and visual evoked potentials were obtained. All patients were given methylprednisolone therapy. Patients were followed up for 6 months. Outcome was assessed using modified Barthel index. A modified Barthel index score of ≤12 indicated a poor prognosis. RESULTS: Majority (n = 49; 61.25%) of patients had idiopathic acute transverse myelitis. Eleven cases had neuromyelitis optica spectrum disorders (8 had anti-aquaporin antibody positivity). Multiple sclerosis was diagnosed in 7 cases. Eight cases had infectious or parainfectious myelitis. Longitudinally extensive transverse myelitis was noted in 66 (82.5%) patients. Seventeen patients had abnormalities in the brain. Majority of patients improved following methylprednisolone therapy. On univariate analysis, delay in administering methylprednisolone therapy, poor modified Barthel index at discharge, and extensive cord involvement were associated with severe residual disability. On multivariate analysis, delayed initiation of methylprednisolone was identified as a poor prognostic factor. CONCLUSION: A variety of inflammatory, infective, demyelinating, and autoimmune disorders present with acute transverse myelopathy. Early institution of methylprednisolone reduces the disability in these patients.

Gut microbiome analysis in neuromyelitis optica reveals overabundance of Clostridium perfringens.

T cells from neuromyelitis optica (NMO) patients, which recognize the immunodominant epitope of aquaporin-4, exhibit Th17 polarization and cross-react with a homologous sequence of a Clostridium perfringens adenosine triphosphate-binding cassette transporter. Therefore, this commensal microbe might participate in NMO pathogenesis. We examined the gut microbiome by PhyloChip G3 from 16 NMO patients, 16 healthy controls (HC), and 16 multiple sclerosis patients. A significant difference in the abundance of several microbial communities was observed between NMO and HC (Adonis test, p = 0.001). Strikingly, C. perfringens was overrepresented in NMO (p = 5.24 × 10(-8) ). These observations support a potential role for C. perfringens in NMO pathogenesis. Ann Neurol 2016;80:443-447.

Demyelinating syndrome in SLE: review of different disease subtypes and report of a case series.

Demyelinating syndrome (DS) is a rare manifestation of systemic lupus erythematosus (SLE) (1%) with high clinical heterogeneity and potentially severe prognosis. It can represent a diagnostic and therapeutic challenge for clinicians. A recent study described 5 different patterns of demyelinating disease presentation, characterised by specific clinical, laboratory and brain and spine magnetic resonance imaging abnormalities: 1) neuromyelitis optica; 2) neuromyelitis optica spectrum disorders; 3) DS prevalently involving the brain; 4) DS prevalently involving the brainstem; 5) clinically isolated syndrome. In this review we briefly discuss typical characteristics of each DS presentation in SLE and we describe 5 illustrative clinical cases, one for each subset of DS, considering both diagnostic and therapeutic options.

[Clinical characteristics of neuromyelitis optica spectrum disorders associated with syringomyelia].

Objective: To analyze the clinical characteristics of neuromyelitis optica spectrum disorders (NMOSD) associated with syringomyelia (SML). Methods: The clinical manifestations, laboratory parameters and imaging findings of 7 patients with NMOSD associated with SML during June 2008 to August 2016 from The Third Affiliated Hospital of Sun Yat-sen University were retrospectively analyzed. Results: Six patients were female and 1 was male, with ages ranging from 27-67 years, the course of the disease was 3-12 years, recurrence was 2-7 times, all the patients were cerebrospinal fluid oligoclonal bands (CSF OCB) negative, 5 patients were positive for aquaporin-4-antibody/NMO-IgG. Sensory and motor dysfunction, bowel or bladder dysfunction were the common clinical manifestation, and pain was a significant symptom. Syringomyelia was predominantly located in C4-T10, cavity length 2-6 mm, diameter 0.8-3.6 mm; 5 had lobes involvement and 6 had long segmental spinal cord involvement. Conclusions: NMOSD associated with SML had a high frequency of occurrence in female, with the clinical characteristics of limb pain, easy progression, high recurrence rate and disability rate. The anti AQP4 antibody were commonly seen in these patients. Syringomyelia was predominantly located in the lower cervical and upper thoracic spinal cord, the lobar and longitudinally extensive transverse myelitis were frequently found in patients with NMOSD associated with SML.

Beginning of the end of two-stage theory purporting that inflammation then degeneration explains pathogenesis of progressive multiple sclerosis.

PURPOSE OF REVIEW: The review discusses future directions in research on multiple sclerosis and neuromyelitis optica, as long-held beliefs about these diseases are undermined with data from recent clinical trials. RECENT FINDINGS: Results of clinical trials for registration (phase 3) were reported in the last year. Anti-inflammatory approaches, such as daclizumab high-yield process targeting IL-2 receptor, and ocrelizumab targeting CD20 B cells, confirmed a beneficial role of immune suppression in relapsing-remitting disease. And now for the first time achieving the primary end point in primary progressive multiple sclerosis was attained with ocrelizumab. SUMMARY: The results in the past year challenge the long-held belief that relapsing-remitting disease is inflammatory, whereas progressive forms of the disease are 'less inflammatory' and more 'degenerative.'

Neuromyelitis optica study model based on chronic infusion of autoantibodies in rat cerebrospinal fluid.

BACKGROUND: Devic's neuromyelitis optica (NMO) is an autoimmune astrocytopathy, associated with central nervous system inflammation, demyelination, and neuronal injury. Several studies confirmed that autoantibodies directed against aquaporin-4 (AQP4-IgG) are relevant in the pathogenesis of NMO, mainly through complement-dependent toxicity leading to astrocyte death. However, the effect of the autoantibody per se and the exact role of intrathecal AQP4-IgG are still controversial. METHODS: To explore the intrinsic effect of intrathecal AQP4-IgG, independent from additional inflammatory effector mechanisms, and to evaluate its clinical impact, we developed a new animal model, based on a prolonged infusion of purified immunoglobulins from NMO patient (IgG(AQP4+), NMO-rat) and healthy individual as control (Control-rat) in the cerebrospinal fluid (CSF) of live rats. RESULTS: We showed that CSF infusion of purified immunoglobulins led to diffusion in the brain, spinal cord, and optic nerves, the targeted structures in NMO. This was associated with astrocyte alteration in NMO-rats characterized by loss of aquaporin-4 expression in the spinal cord and the optic nerves compared to the Control-rats (p = 0.001 and p = 0.02, respectively). In addition, glutamate uptake tested on vigil rats was dramatically reduced in NMO-rats (p = 0.001) suggesting that astrocytopathy occurred in response to AQP4-IgG diffusion. In parallel, myelin was altered, as shown by the decrease of myelin basic protein staining by up to 46 and 22 % in the gray and white matter of the NMO-rats spinal cord, respectively (p = 0.03). Loss of neurofilament positive axons in NMO-rats (p = 0.003) revealed alteration of axonal integrity. Then, we investigated the clinical consequences of such alterations on the motor behavior of the NMO-rats. In a rotarod test, NMO-rats performance was lower compared to the controls (p = 0.0182). AQP4 expression, and myelin and axonal integrity were preserved in AQP4-IgG-depleted condition. We did not find a major immune cell infiltration and microglial activation nor complement deposition in the central nervous system, in our model. CONCLUSIONS: We establish a link between motor-deficit, NMO-like lesions and astrocytopathy mediated by intrathecal AQP4-IgG. Our study validates the concept of the intrinsic effect of autoantibody against surface antigens and offers a model for testing antibody and astrocyte-targeted therapies in NMO.

Complement-independent retinal pathology produced by intravitreal injection of neuromyelitis optica immunoglobulin G.

BACKGROUND: Neuromyelitis optica (NMO), an autoimmune inflammatory disease of the central nervous system, is often associated with retinal abnormalities including thinning of the retinal nerve fiber layer and microcystic changes. Here, we demonstrate that passive transfer of an anti-aquaporin-4 autoantibody (AQP4-IgG) produces primary retinal pathology. METHODS: AQP4-IgG was delivered to adult rat retinas by intravitreal injection. Rat retinas and retinal explant cultures were assessed by immunofluorescence. RESULTS: Immunofluorescence showed AQP4-IgG deposition on retinal Müller cells, with greatly reduced AQP4 expression and increased glial fibrillary acidic protein by 5 days. There was mild retinal inflammation with microglial activation but little leukocyte infiltration and loss of retinal ganglion cells by 30 days with thinning of the ganglion cell complex. Interestingly, the loss of AQP4 was complement independent as seen in cobra venom factor-treated rats and in normal rats administered a mutated AQP4-IgG lacking complement effector function. Exposure of ex vivo retinal cultures to AQP4-IgG produced a marked reduction in AQP4 expression by 24 h, which was largely prevented by inhibitors of endocytosis or lysosomal acidification. CONCLUSIONS: Passive transfer of AQP4-IgG results in primary, complement-independent retinal pathology, which might contribute to retinal abnormalities seen in NMO patients.

Application of diffusional kurtosis imaging to detect occult brain damage in multiple sclerosis and neuromyelitis optica.

Multiple sclerosis (MS) and neuromyelitis optica (NMO) are two common types of inflammatory demyelinating disease of the central nervous system. Early distinction of NMO from MS is crucial but quite challenging. In this study, 13 NMO spectrum disorder patients (Expanded Disability Status Scale (EDSS) of 3.0 ± 1.7, ranging from 2 to 6.5; disease duration of 5.3 ± 4.7 years), 17 relapsing-remitting MS patients (EDSS of 2.6 ± 1.4, ranging from 1 to 5.5; disease duration of 7.9 ± 7.8 years) and 18 healthy volunteers were recruited. Diffusional kurtosis imaging was employed to discriminate NMO and MS patients at the early or stable stage from each other, and from healthy volunteers. The presence of alterations in diffusion and diffusional kurtosis metrics in normal-appearing white matter (NAWM) and diffusely increased mean diffusivity (MD) in the cortical normal-appearing gray matter (NAGM) favors the diagnosis of MS rather than NMO. Meanwhile, normal diffusivities and kurtosis metrics in all NAWM as well as increases in MD in the frontal and temporal NAGM suggest NMO. Our results suggest that diffusion and diffusional kurtosis metrics may well aid in discriminating the two diseases.

[The correlation factor analysis for conversion of clinically isolated syndrome to multiple sclerosis and neuromyelitis optica].

OBJECTIVE: To analyze the features of patients who converted from clinically isolated syndrome (CIS) to multiple sclerosis (MS) and neuromyelitis optica (NMO) and explore the correlated factors. METHODS: A total of 151 patients admitted in our unit as CIS from January 2009 to December 2014 were enrolled in the study. All patients were divided into the following four groups by locations of the initial lesion, which were the spinal cord, the optic nerve, the brain stem and the multifocal lesions. Data were collected at the baseline including demographics, expanded disability status scale (EDSS) score, site of CIS, presence or absence of cerebrospinal fluid (CSF) oligoclonal bands (OB) and serum aquaporin-4 antibody (AQP4-Ab), evoked potential (EP) and MRI lesions. The conversion rates from CIS to clinically definite MS or NMO were calculated and the correlated factors were explored. RESULTS: With a mean follow-up period of (44.11±17.62)months, 46/151(30.5%) patients converted to MS, 28/151 (18.5%) to definite NMO and 66/151 patients(43.7%)remained as CIS. Other patients were converted to optic neuritis(4/151), one-time transverse myelitis(3/151), acute disseminated encephalomyelitis (1/151) and Balo concentric sclerosis(3/151) . The EDSS score was significantly higher in patients converted to NMO than those converted to MS (P=0.003). The initial manifestation of optic neuritis significantly correlated with the conversion to NMO (P=0.000), while the initial manifestation of CIS with multifocal lesions significantly correlated with the conversion to MS (P=0.000). Neither the isolated BAEP (P=0.703), VEP (P=0.076), SEP (P=0.915) nor the combination of two (P=0.546)or three (P=1.000) of the above parameters could help to distinguish the conversion to MS or NMO. More patients with positive CSF-OB converted to MS (P=0.001), while more patients with positive serum AQP4-Ab converted to NMO (P=0.001). More patients were serum AQP4-Ab positive in those converted to NMO than those converted to MS (P=0.000). Lesions longer than three vertebral segments were dominant in patients converted to NMO (P=0.000). The logistic regression analysis revealed that factors correlated with conversion from CIS to MS were the initial CIS manifestation of multifocal lesions (OR=4.775, P=0.002), positive CSF-OB (OR=7.794, P=0.002) and VEP abnormality (OR=7.251, P=0.001). Factors correlated with conversion from CIS to NMO were female in gender (OR=12.536, P=0.019), positive serum AQP4-Ab (OR=36.410, P=0.002), lesions longer than three vertebral segments (OR=93.602, P=0.001), abnormal VEP and SEP (OR=18.448, P=0.002; OR=12.731, P=0.016). CONCLUSIONS: Factors correlated with the conversion from CIS to MS are initial CIS manifestation of multifocal lesions, positive CSF-OB and abnormal VEP, while those correlated with the conversion from CIS to NMO are female in gender, positive serum AQP4-Ab, initial CIS manifestation with optic nerve, lesions involved more than three vertebral segments and abnormal VEP and SEP.

Follicular Helper CD4+ T Cells in Human Neuroautoimmune Diseases and Their Animal Models.

Follicular helper CD4(+) T (TFH) cells play a fundamental role in humoral immunity deriving from their ability to provide help for germinal center (GC) formation, B cell differentiation into plasma cells and memory cells, and antibody production in secondary lymphoid tissues. TFH cells can be identified by a combination of markers, including the chemokine receptor CXCR5, costimulatory molecules ICOS and PD-1, transcription repressor Bcl-6, and cytokine IL-21. It is difficult and impossible to get access to secondary lymphoid tissues in humans, so studies are usually performed with human peripheral blood samples as circulating counterparts of tissue TFH cells. A balance of TFH cell generation and function is critical for protective antibody response, whereas overactivation of TFH cells or overexpression of TFH-associated molecules may result in autoimmune diseases. Emerging data have shown that TFH cells and TFH-associated molecules may be involved in the pathogenesis of neuroautoimmune diseases including multiple sclerosis (MS), neuromyelitis optica (NMO)/neuromyelitis optica spectrum disorders (NMOSD), and myasthenia gravis (MG). This review summarizes the features of TFH cells, including their development, function, and roles as well as TFH-associated molecules in neuroautoimmune diseases and their animal models.

Experimental mouse model of optic neuritis with inflammatory demyelination produced by passive transfer of neuromyelitis optica-immunoglobulin G.

BACKGROUND: Although optic neuritis (ON) is a defining feature of neuromyelitis optica (NMO), appropriate animal models of NMO ON are lacking. Most NMO patients are seropositive for immunoglobulin G autoantibodies (NMO-IgG) against the astrocyte water channel aquaporin-4 (AQP4). METHODS: Several approaches were tested to develop a robust, passive-transfer mouse model of NMO ON, including NMO-IgG and complement delivery by: (i) retrobulbar infusion; (ii) intravitreal injection; (iii) a single intracranial injection near the optic chiasm; and (iv) 3-days continuous intracranial infusion near the optic chiasm. RESULTS: Little ON or retinal pathology was seen using approaches (i) to (iii). Using approach (iv), however, optic nerves showed characteristic NMO pathology, with loss of AQP4 and glial fibrillary acidic protein immunoreactivity, granulocyte and macrophage infiltration, deposition of activated complement, demyelination and axonal injury. Even more extensive pathology was created in mice lacking complement inhibitor protein CD59, or using a genetically modified NMO-IgG with enhanced complement effector function, including significant loss of retinal ganglion cells. In control studies, optic nerve pathology was absent in treated AQP4-deficient mice, or in wild-type mice receiving control (non-NMO) IgG and complement. CONCLUSION: Passive transfer of NMO-IgG and complement by continuous infusion near the optic chiasm in mice is sufficient to produce ON with characteristic NMO pathology. The mouse model of NMO ON should be useful in further studies of NMO pathogenesis mechanisms and therapeutics.

The impact of diagnostic criteria for neuromyelitis optica in patients with MS: a 10-year follow-up of the South Atlantic Project.

BACKGROUND: It is recognized that there is a particular geographic and ethnic distribution of neuromyelitis optica (NMO) among Caucasian and non-Caucasian populations. OBJECTIVE: To review the diagnoses of patients whom were enrolled in the South Atlantic Project, a Brazilian multiple sclerosis (MS) survey performed from 1995-1998, and to identify NMO and MS case frequencies. METHODS: We reviewed the data from a 10-year follow-up of MS patients. To apply the current diagnostic criteria, the neurologists were asked to collect clinical and laboratory data from the medical records of study patients treated from 1999-2009. RESULTS: The spectrum of inflammatory demyelinating disease in 322 patients (67% white; 33% African-Brazilian) was: 49 (15%) with NMO; 14 (4%) with NMO syndromes; 10 (3%) with acute disseminated encephalomyelitis (ADEM); one isolated tumefactive brain lesion; 249 (77%) with MS (151 with relapsing-remitting MS (RRMS), 70 with secondary progressive MS (SPMS) and 27 with primary progressive MS (PPMS)). Disability was more severe in NMO and PPMS. One-third of the NMO patients had died. CONCLUSIONS: The frequency of NMO was 6.8% in São Paulo and 20.5% in Rio de Janeiro, and mainly seen in persons of African descent, which strengthens the hypothesis of there being an ethnic association of this disease. We recommend that epidemiological studies on MS that were performed previously be reviewed again, to ensure more accurate diagnoses.