Shuhei Nishiyama

Clinical and MRI features of Japanese patients with multiple sclerosis positive for NMO-IgG

This study investigates the relation between the serological status of NMO (neuromyelitis optica)-IgG and the clinical and MRI features in Japanese patients with multiple sclerosis. Serum NMO-IgG was tested in 35 Japanese patients diagnosed with multiple sclerosis, including 19 with the optic–spinal form of multiple sclerosis (OSMS), three with the spinal form of multiple sclerosis (SMS), and 13 with the conventional form of multiple sclerosis (CMS), which affects the brain. NMO-IgG was detected in 14 patients, 12 with OSMS and 2 with CMS. In these patients, longitudinally extensive (>3 vertebral segments) spinal cord lesions (93% v 57%) and permanent, complete blindness (no perception of light) in at least one eye (50% v 0%) were the noticeable features as compared with NMO-IgG-negative OSMS. The two patients having CMS with NMO-IgG had unusual brain lesions, but in other respects had features suggesting OSMS. NMO-IgG was detected in more than half the number of patients with OSMS and in some patients with CMS. This newly discovered serum autoantibody was markedly associated with longitudinally extensive spinal cord lesions and with complete blindness, suggesting severe optic–spinal disease.

Presence of six different lesion types suggests diverse mechanisms of tissue injury in neuromyelitis optica

Neuromyelitis optica (NMO) is an autoimmune disease targeting aquaporin 4 (AQP4), localized mainly at the astrocytic foot processes. Loss of AQP4 and glial fibrillary acidic protein (GFAP) was reported, but the pathological significance of astrocytopathy is still controversial. Here we show that active lesions in NMO display a wide spectrum of pathology even within a single tissue block of an individual patient. We have distinguished six different lesion types. The first reflects complement deposition at the surface of astrocytes, associated with granulocyte infiltration and astrocyte necrosis and followed by demyelination, global tissue destruction and the formation of cystic, necrotic lesions (lesion type 2). Such destructive lesions lead to Wallerian degeneration in lesion-related tracts (lesion type 3). Around active NMO lesions AQP4 may selectively be lost in the absence of aquaporin 1 (AQP1) loss or other structural damage (lesion type 4). Another pattern is characterized by clasmatodendrosis of astrocytes, defined by cytoplasmic swelling and vacuolation, beading and dissolution of their processes and nuclear alterations resembling apoptosis, which was associated with internalization of AQP4 and AQP1 and astrocyte apoptosis in the absence of complement activation. Such lesions give rise to extensive astrocyte loss, which may occur in part in the absence of any other tissue injury, such as demyelination or axonal degeneration (lesion type 5). Finally, lesions with a variable degree of astrocyte clasmatodendrosis are found, which show plaque-like primary demyelination that is associated with oligodendrocyte apoptosis, but with preservation of axons (lesion type 6). In active multiple sclerosis (MS) lesions astrocytes reveal changes of reactive protoplasmatic or fibrillary gliosis. Only in a subset of lesions, in patients with aggressive disease, loss of AQP4 is observed in the initial stage of their formation, which is associated with retraction of astrocyte processes in the absence of complement deposition, granulocyte infiltration or loss of AQP1 or astrocytes. Our data underline the primary assault of astrocytes in NMO lesions, but also indicate that different mechanisms of tissue injury operate in parallel in the same patient and even within the same lesion.

A case of NMO seropositive for aquaporin-4 antibody more than 10 years before onset

Neuromyelitis optica (NMO) is characterized by severe optic neuritis and longitudinally extended transverse myelitis (LETM). The clinical and laboratory features of NMO are different from multiple sclerosis (MS).1 An autoantibody to aquaporin-4 (AQP4) has been detected exclusively in the NMO sera.1 Moreover, we demonstrated an extensive loss of AQP4 and glial fibrillary acidic protein immunoreactivities in the perivascular regions with complement and immunoglobulin deposition in NMO that suggests astrocytic impairment. However, when AQP4 antibody is produced in patients with NMO is unknown, and thus it remains unresolved whether there are long-term asymptomatic AQP4 antibody–positive carriers, whether AQP4 antibody alone can be pathogenic, and whether AQP4 antibody is produced secondarily as a result of tissue destruction in attacks of NMO. We herein report a case of NMO in which AQP4 antibody was detected years before the NMO onset. ### Case report. A 34-year-old healthy woman without previous history of inflammatory or neurologic diseases noticed temporary skin eruptions on her chest and shoulders in June 2007. A dermatologist made the diagnosis of eczema. Three weeks later, when the skin eruptions subsided, she noted progressive paresthesia in the chest and toes. Within a few days, she could not walk well due to right leg weakness, and then she was hospitalized. Neurologic examination on …

Aquaporin-4 antibody-positive cases beyond current diagnostic criteria for NMO spectrum disorders

Objectives: To analyze aquaporin-4 (AQP4) antibody–positive patients who do not fulfill the current diagnostic criteria of neuromyelitis optica (NMO) and NMO spectrum disorders (NMOSD). Methods: We used a cell-based assay (CBA) with AQP4-transfected cells to detect AQP4 antibody in 298 consecutive patients with inflammatory CNS disorders seen at Tohoku University Hospital from 2007 to 2012. The patients were diagnosed as NMO, NMOSD, multiple sclerosis, or others using the respective current diagnostic criteria. The seropositive samples by CBA were also tested using a commercial ELISA. Results: Seventy-two patients were AQP4 antibody positive. Among them, 18.1% (13/72) did not meet the NMO or NMOSD criteria (7 with monophasic optic neuritis, 2 with attacks restricted to the brainstem, and 4 with myelitis with less than 3 vertebral segments) and 84.6% (11/13) of these had only a single attack. The ELISA results were negative in 38.4% (5/13) of those patients, and they had lower antibody titers by CBA than patients with NMO/NMOSD. Although these patients had a shorter follow-up and few attacks, they shared some clinical features with NMO/NMOSD patients such as onset age, female predominance, presence of other autoantibodies, severe optic neuritis attacks, centrally located spinal cord lesions, persisting hiccups, and nausea or vomiting episodes. Conclusions: AQP4 antibody–positive patients with single or recurrent attacks of optic neuritis, myelitis, or brain/brainstem disease not fulfilling the current criteria of NMO or NMOSD may not be uncommon, and they should also be included in the NMO spectrum.

Neuromyelitis optica should be classified as an astrocytopathic disease rather than a demyelinating disease

Neuromyelitis optica (NMO) is characterized by severe optic neuritis and transverse myelitis. The relationship of NMO to multiple sclerosis (MS) has long been debated, but NMO has been classified as a demyelinating disease. Since the discovery of an NMO‐specific autoantibody to aquaporin 4 (AQP4), a dominant water channel in the central nervous system densely expressed on end‐feet of astrocytes, the clinical, magnetic resonance imaging and laboratory findings to distinguish NMO from MS have been clarified. Furthermore, pathological studies showed an extensive loss of immunoreactivities to astrocytic proteins, AQP4 and glial fibrillary acidic protein (GFAP), and perivascular deposition of immunoglobulins and activated complements with a relative preservation of the staining of myelin basic protein (MBP) in acute NMO lesions, but not in MS. In support of these pathological findings, the GFAP levels in the cerebrospinal fluid (CSF) during acute exacerbation of NMO are remarkably elevated compared with MBP and neurofilament, whereas the CSF‐GFAP in MS is not different from those in controls. Additionally, recent experimental studies have convincingly shown that AQP4 antibody is pathogenic in causing astorocytic destruction and dysfunction in vitro, ex vivo and in vivo. These findings strongly suggest that damage of astrocytes is far more severe than those of myelin and neurons, and that autoimmune astrocytopathy is the primary pathology in NMO. Based on these accumulated data, we propose that NMO should be classified as an astrocytopathic disease rather than a demyelinating disease.

Severe demyelination but no astrocytopathy in clinically definite neuromyelitis optica with anti-myelin-oligodendrocyte glycoprotein antibody

We report a patient with neuromyelitis optica (NMO) presenting anti-myelin-oligodendrocyte glycoprotein (MOG)-seropositive, in whom biomarkers of demyelination and astrocyte damage were measured during an acute attack. A 31-year-old man developed right optic neuritis followed by longitudinally extensive transverse myelitis, fulfilling the criteria for definite NMO. He was anti-MOG-seropositive and anti-aquaporin-4 seronegative. The myelin basic protein level was markedly elevated whereas glial fibrillary acidic protein was not detectable in cerebrospinal fluid during an acute attack. His symptoms quickly improved after high-dose methylprednisolone therapy. This case suggests that NMO patients with anti-MOG may have severe demyelination in the absence of astrocyte injury.

MRI and retinal abnormalities in isolated optic neuritis with myelin oligodendrocyte glycoprotein and aquaporin-4 antibodies: a comparative study

Acute optic neuritis (ON) typically presents with ocular pain and low visual acuity (VA), and there is a risk of permanent vision loss if ON is not managed properly.1 ON may be the first symptom of inflammatory diseases of the central nervous system (CNS), such as multiple sclerosis and neuromyelitis optica spectrum disorder (NMOSD). Recently, we reported some distinct characteristics between seropositive anti-aquaporin-4 (anti-AQP4) patients and seropositive antimyelin oligodendrocyte glycoprotein (anti-MOG) patients with NMOSD, using our in-house cell-based assays (CBA). However, patients with a single attack of unilateral ON were not included in our previous study. None of the previous studies of anti-MOG+ patients performed orbital MRI or optical coherence tomography (OCT) segmentation analyses, which may have diagnostic and prognostic implications. To address these issues, we evaluated the diagnostic utility of the anti-MOG assay and compared the MRI and OCT findings of anti-MOG+ and anti-AQP4+ patients with isolated ON. ### Patients We investigated 28 affected ON eyes from 21 consecutive anti-AQP4 seronegative patients aged 12 years or older who presented with isolated ON (4 cases with simultaneous bilateral ON, 3 cases with relapsing unilateral ON, and 14 cases with a single attack of unilateral ON) and were admitted to Tohoku University Hospital between 2011 and 2013. We excluded patients with ON already associated with brain and/or spinal cord MRI lesions. We compared anti-MOG+ ON eyes with nine affected ON eyes from eight anti-AQP4+ patients with isolated ON (one simultaneous bilateral ON). Severe VA loss was set at 0.1 in the decimal Japanese chart (equivalent to 20/200).2 ### Orbital MRI All patients performed orbital imaging using a 1.5 T MRI. We measured the short τ inversion recovery (STIR) and/or T2-weighted image hyperintense lesions …

MOG antibody–positive, benign, unilateral, cerebral cortical encephalitis with epilepsy

Objective: To describe the features of adult patients with benign, unilateral cerebral cortical encephalitis positive for the myelin oligodendrocyte glycoprotein (MOG) antibody. Methods: In this retrospective, cross-sectional study, after we encountered an index case of MOG antibody–positive unilateral cortical encephalitis with epileptic seizure, we tested for MOG antibody using our in-house, cell-based assay in a cohort of 24 consecutive adult patients with steroid-responsive encephalitis of unknown etiology seen at Tohoku University Hospital (2008–2014). We then analyzed the findings in MOG antibody–positive cases. Results: Three more patients, as well as the index case, were MOG antibody–positive, and all were adult men (median age 37 years, range 23–39 years). The main symptom was generalized epileptic seizure with or without abnormal behavior or consciousness disturbance. Two patients also developed unilateral benign optic neuritis (before or after seizure). In all patients, brain MRI demonstrated unilateral cerebral cortical fluid-attenuated inversion recovery hyperintense lesions, which were swollen and corresponded to hyperperfusion on SPECT. CSF studies showed moderate mononuclear pleocytosis with some polymorphonuclear cells and mildly elevated total protein levels, but myelin basic protein was not elevated. A screening of encephalitis-associated autoantibodies, including aquaporin-4, glutamate receptor, and voltage-gated potassium channel antibodies, was negative. All patients received antiepilepsy drugs and fully recovered after high-dose methylprednisolone, and the unilateral cortical MRI lesions subsequently disappeared. No patient experienced relapse. Conclusions: These MOG antibody–positive cases represent unique benign unilateral cortical encephalitis with epileptic seizure. The pathology may be autoimmune, although the findings differ from MOG antibody–associated demyelination and Rasmussen and other known immune-mediated encephalitides.

Changes in Th17 and regulatory T cells after fingolimod initiation to treat multiple sclerosis

Fingolimod has demonstrated efficacy in patients with multiple sclerosis (MS), and patients become gradually lymphopenic after a few days of treatment, with selective reductions in CD4+ subsets. We observed an increase in the frequencies of circulating regulatory T cells after fingolimod administration. However, we also found that half of patients had increased proportion of circulating Th17 cells in CD4+ T cells after treatment (including a patient with MS relapses), whereas the others showed lower frequencies of Th17 cells, indicating some variability among patients. Further studies may confirm if slower reduction of circulating Th17 cells following fingolimod initiation predisposes to relapses.

Myelin injury without astrocytopathy in neuroinflammatory disorders with MOG antibodies

Objective To compare myelin and astrocyte injury in patients with antibodies against myelin oligodendrocyte glycoprotein (anti-MOG) or aquaporin-4 (anti-AQP4), and multiple sclerosis (MS). Methods Myelin basic protein (MBP) and glial fibrillary acidic protein (GFAP) levels were measured in the cerebral spinal fluid (CSF) from anti-MOG+ or anti-AQP4+ patients tested in both sera and CSF by cell-based assays with live transfected cells. Results In total, 75.6% (68/90) of the patients were positive for either anti-MOG or anti-AQP4 antibodies in both serum and CSF; 74.2% (23/31) were anti-MOG+, and 76.3% (45/59) were anti-AQP4+. No patients were only CSF positive or were positive for both anti-MOG and anti-AQP4 antibodies, and none of the MS patients or controls had these autoantibodies in the serum or CSF. MBP levels were elevated in the anti-MOG+ cases compared to the multiple sclerosis (MS) patients, and the levels found were similar between anti-MOG+ cases and anti-AQP4+ neuromyelitis optica spectrum disorder (NMOSD) cases. Meanwhile, GFAP was only elevated in the anti-AQP4+ NMOSD. Moreover, CSF pleocytosis, high protein levels, and oligoclonal IgG band negativity distinguished the anti-MOG+ cases from MS patients. Conclusions Myelin injury was more severe in the anti-MOG+ cases than in the MS cases, and anti-MOG+ cases have differences in the CSF characteristics compared to MS. GFAP elevation in anti-AQP4+ cases was absent in anti-MOG+ patients (even in cases with NMOSD phenotype), indicating that immune-mediated astrocytopathy is unique to anti-AQP4+ patients. Our study suggests that anti-MOG+ cases are distinct from MS and anti-AQP4+ NMOSD.