Neuromyelitis Optica

Paediatric multiple sclerosis (MS) represents less than 5 % of the MS population, but patients with paediatric-onset disease reach permanent disability at a younger age than adult-onset patients. Accurate diagnosis at presentation and optimal long-term treatment are vital to mitigate ongoing neuroinflammation and irreversible neurodegeneration. However, it may be difficult to early differentiate paediatric MS from acute disseminated encephalomyelitis (ADEM) and neuromyelitis optica spectrum disorders (NMOSD), as they often have atypical presentation that differs from that of adult-onset MS. The purpose of this review is to summarize the updated views on diagnostic criteria, imaging, histopathology and treatment choices.

Genes encoding antigen-presenting molecules within the human major histocompatibility complex (MHC) account for the highest component of genetic risk for many neurological diseases, such as multiple sclerosis, neuromyelitis optica, Parkinson's disease, Alzheimer's disease, schizophre-nia, myasthenia gravis and amyotrophic lateral sclerosis. Myriad genetic, immunological and environmental factors may contribute to an individ-ual's susceptibility to neurological disease. Here, we review and discuss the decades long research on the influence of genetic variation at the MHC locus and the role of immunogenetic killer cell immunoglobulin-like receptor (KIR) loci in neurological diseases, including multiple sclerosis, neuromyelitis optica, Parkinson's disease, Alzheimer's disease, schizophre-nia, myasthenia gravis and amyotrophic lateral sclerosis. The findings of immunogenetic association studies are consistent with a polygenic model of inheritance in the heterogeneous and multifactorial nature of complex traits in various neurological diseases. Future investigation is highly recommended to evaluate both coding and non-coding variation in immuno-genetic loci using high-throughput high-resolution next-generation sequencing technologies in diverse ethnic groups to fully appreciate their role in neurological diseases.

Neurologists commonly use therapeutic plasma exchange (TPE, also known as plasmapheresis or therapeutic apheresis) to treat a number of conditions. This concise review examines the most common neurologic indications for therapeutic plasma exchange. It focuses on Guillain-Barrè syndrome and myasthenia gravis and also the role of TPE in chronic inflammatory demyelinating polyneuropathy, Lambert-Eaton syndrome, multiple sclerosis, neuromyelitis optica, paraproteinemic polyneuropathy, and Sydenham's chorea. As with any treatment, the proven efficacy, cost, side effects, and availability must be considered before initiation of therapy.

Documentation of muscle pathology compatible with targeting of sarcolemmal aquaporin-4 (AQP4) by complement-activating IgG implies involvement of organs beyond the central nervous system in neuromyelitis optica spectrum disorders. We report on a 51-year-old woman who had relapsing optic neuritis, transverse myelitis, AQP4-IgG seropositivity, and recurrent myalgias with hyperCKemia. A muscle biopsy revealed scattered myofibers with internal nuclei, atrophy, and regeneration but no necrosis. Mild inflammatory exudates, in endomysial and perivascular spaces, consisted of lymphocytes, histiocytes, and scattered eosinophils. The sarcolemma exhibited loss of AQP4 and deposition of IgG and complement activation products, characteristics not seen in control biopsy samples of healthy muscle and immune-mediated myopathies. Recurrent hyperCKemia accompanying AQP4-IgG seropositivity reflects targeting of skeletal muscle AQP4 by pathogenic IgG. The entity of autoimmune AQP4 myopathy extends the ...

Neuromyelitis optica (NMO) is a rare relapsing auto-immune disease of the central nervous system which is sometimes found in association with other autoimmune disorders including Sjogren's syndrome. We present the case of a middle aged female with Sjogren's syndrome (SS) and Neuromyelitis optica spectrum disorders (NMOSD) who had a rapidly declining neurological illness that responded to immunosuppressive therapy. A 51-year-old female with Sjogren's syndrome and recent history of varicella zoster infection presented with right upper and lower extremity weakness of one week duration. She was noted to have contrast enhancement at C2-C4 cord levels on cervico-thoracic MRI. Comprehensive work up was negative except for presence of a mild lymphocytic pleocytosis and oligoclonal bands in the CSF. She was diagnosed with transverse myelitis secondary to varicella zoster infection and was treated with high dose steroids in addition to acyclovir with improvement in her symptoms. T...

To determine the frequency and clinical-radiological associations of antibodies to myelin oligodendrocyte glycoprotein (MOG) and aquaporin-4 (AQP4) in children presenting with neuromyelitis optica (NMO) and limited forms. Children with a first event of NMO, recurrent (RON), bilateral ON (BON), longitudinally extensive transverse myelitis (LETM) or brainstem syndrome (BS) with a clinical follow-up of more than 12 months were enrolled. Serum samples were tested for MOG- and AQP4-antibodies using live cell-based assays. 45 children with NMO (n=12), LETM (n=14), BON (n=6), RON (n=12) and BS (n=1) were included. 25/45 (56%) children had MOG-antibodies at initial presentation (7 NMO, 4 BON, 8 ON, 6 LETM). 5/45 (11%) children showed AQP4-antibodies (3 NMO, 1 LETM, 1 BS) and 15/45 (33%) were seronegative for both antibodies (2 NMO, 2 BON, 4 RON, 7 LETM). No differences were found in the age at presentation, sex ratio, frequency of oligoclonal bands or median EDSS at last follow-up between t...

Neuromyelitis optica (NMO) is the first inflammatory autoimmune demyelinating disease of the CNS for which a specific tissue target molecule has been identified—the astrocytic water channel aquaporin-4 (AQP4). Immunological insights have propelled significant advances in understanding the clinical, radiologic and immunopathologic characteristics of the disease in the last 5 years. In this review, we describe features distinguishing CNS AQP4 autoimmunity from classical multiple sclerosis (MS). In NMO, disease attacks preferentially involve the optic nerves and spinal cord (hence the name), but neurological signs in the initial attack of AQP4 autoimmunity in children commonly involve the brain. A clinically validated serum biomarker, NMO–IgG, distinguishes relapsing CNS inflammatory demyelinating disorders related to NMO from MS. The NMO–IgG autoantibody is AQP4-specific. Clinical, radiological and immunopathological data support its role in the pathogenesis of NMO spectrum disorders. Lesions characteristic of NMO are distinct from MS: AQP4 and its coupled glutamate transporter, excitatory amino acid transporter 2 (EAAT2), are lost, with and without associated myelin loss, IgG, IgM and complement are deposited in a vasculocentric pattern, edema and inflammation are prominent. In vitro studies demonstrate that binding of NMO–IgG to astrocytic AQP4 initiates multiple potentially neuropathogenic mechanisms: complement activation, AQP4 and EAAT2 downregulation with disruption of water and glutamate homeostasis, enhanced blood–brain barrier permeability, plasma protein and granulocyte influx, and antibody-dependent cell-mediated cytotoxicity. Development of effective, and potentially curative, therapies requires validated models of the disease, in animals and cell culture systems.

Neuromyelitis optica (NMO) or Devic's disease is an autoimmune, inflammatory and demyelinating central nervous system disorder that affects mainly to optic nerve and spinal cord. Recent advances have substantially permitted to expand the knowledge about this entity. To present a clinical update on the current understanding of the nature, progression, diagnosis and treatment of NMO. Due to its demyelinating nature and its recurrent behavior in most cases, NMO was first considered a form of multiple sclerosis (MS). However, recent findings have led to the conclusion that NMO is a distinct disorder, presenting important immunopathological, clinical, prognostic and therapeutic differences from MS. Fundamental in the under-standing of the disease was the recent discovery of antibodies directed against aquaporin-4 (anti-AQP4, also known as NMO-IgG), which are present in the majority of NMO cases clinically defined, and in a minority of patients with MS. Despite the knowledge on its im...

To determine the frequency and clinical-radiological associations of antibodies to myelin oligodendrocyte glycoprotein (MOG) and aquaporin-4 (AQP4) in children presenting with neuromyelitis optica (NMO) and limited forms. Children with a first event of NMO, recurrent (RON), bilateral ON (BON), longitudinally extensive transverse myelitis (LETM) or brainstem syndrome (BS) with a clinical follow-up of more than 12 months were enrolled. Serum samples were tested for MOG- and AQP4-antibodies using live cell-based assays. 45 children with NMO (n=12), LETM (n=14), BON (n=6), RON (n=12) and BS (n=1) were included. 25/45 (56%) children had MOG-antibodies at initial presentation (7 NMO, 4 BON, 8 ON, 6 LETM). 5/45 (11%) children showed AQP4-antibodies (3 NMO, 1 LETM, 1 BS) and 15/45 (33%) were seronegative for both antibodies (2 NMO, 2 BON, 4 RON, 7 LETM). No differences were found in the age at presentation, sex ratio, frequency of oligoclonal bands or median EDSS at last follow-up between t...