MyMedR

Fulltext Biomarkers of 'acute-onset' chronic inflammatory demyelinating polyneuropathy

Miura Y, Shahrizaila N, Yuki N

Brain, 2015 Mar;138(Pt 3):e335.

PMID: 25183714 DOI: 10.1093/brain/awu252

Are ERM (ezrin/radixin/moesin) proteins targets for autoantibodies in demyelinating neuropathies?

Miyaji K, Shahrizaila N, Umapathi T, Chan YC, Hirata K, Yuki N

Hum Immunol, 2014 Nov;75(11):1089-91.

PMID: 25286001 DOI: 10.1016/j.humimm.2014.09.010

Ezrin, radixin and moesin, which are strongly expressed in the Schwann cell microvilli, are putative targets for autoantibodies in acute or chronic inflammatory demyelinating polyneuropathy (AIDP or CIDP). An association between anti-moesin IgG antibodies and cytomegalovirus-related AIDP has been postulated. None of 41 AIDP patients, including 8 cytomegalovirus-related AIDP patients, and 23 CIDP had IgG or IgM antibodies to ezrin, radixin and moesin; whereas, one patient with cytomegalovirus-related AIDP had anti-ezrin IgM antibodies. Ezrin, radixin and moesin are unlikely targets for autoantibodies in AIDP and CIDP, and the association of anti-moesin antibodies with cytomegalovirus-related AIDP was not confirmed.

Fulltext Different IVIG glycoforms affect in vitro inhibition of anti-ganglioside antibody-mediated complement deposition

Sudo M, Yamaguchi Y, Späth PJ, Matsumoto-Morita K, Ong BK, Shahrizaila N, et al.

PLoS One, 2014;9(9):e107772.

PMID: 25259950 DOI: 10.1371/journal.pone.0107772

Intravenous immunoglobulin (IVIG) is the first line treatment for Guillain-Barré syndrome and multifocal motor neuropathy, which are caused by anti-ganglioside antibody-mediated complement-dependent cytotoxicity. IVIG has many potential mechanisms of action, and sialylation of the IgG Fc portion reportedly has an anti-inflammatory effect in antibody-dependent cell-mediated cytotoxicity models. We investigated the effects of different IVIG glycoforms on the inhibition of antibody-mediated complement-dependent cytotoxicity. Deglycosylated, degalactosylated, galactosylated and sialylated IgG were prepared from IVIG following treatment with glycosidases and glycosyltransferases. Sera from patients with Guillain-Barré syndrome, Miller Fisher syndrome and multifocal motor neuropathy associated with anti-ganglioside antibodies were used. Inhibition of complement deposition subsequent to IgG or IgM autoantibody binding to ganglioside, GM1 or GQ1b was assessed on microtiter plates. Sialylated and galactosylated IVIGs more effectively inhibited C3 deposition than original IVIG or enzyme-treated IVIGs (agalactosylated and deglycosylated IVIGs). Therefore, sialylated and galactosylated IVIGs may be more effective than conventional IVIG in the treatment of complement-dependent autoimmune diseases.

The value of comparing mortality of Guillain-Barré syndrome across different regions

Wong AH, Umapathi T, Shahrizaila N, Chan YC, Kokubun N, Fong MK, et al.

J Neurol Sci, 2014 Sep 15;344(1-2):60-2.

PMID: 24993467 DOI: 10.1016/j.jns.2014.06.021

To study the clinical profile of Guillain-Barré syndrome (GBS) patients who died in 4 Asian countries in order to understand factors underlying any variation in mortality.

Fulltext Antibodies to single glycolipids and glycolipid complexes in Guillain-Barré syndrome subtypes

Shahrizaila N, Kokubun N, Sawai S, Umapathi T, Chan YC, Kuwabara S, et al.

Neurology, 2014 Jul 8;83(2):118-24.

PMID: 24920848 DOI: 10.1212/WNL.0000000000000577

To comprehensively investigate the relationship between antibodies to single glycolipids and their complexes and Guillain-Barré syndrome subtypes and clinical features.

Sensory nerves are frequently involved in the spectrum of fisher syndrome

Shahrizaila N, Goh KJ, Kokubun N, Tan AH, Tan CY, Yuki N

Muscle Nerve, 2014 Apr;49(4):558-63.

PMID: 23893512 DOI: 10.1002/mus.23973

Differing patterns of neurophysiological abnormalities have been reported in patients with Fisher syndrome. Fisher syndrome is rare, and few series have incorporated prospective serial studies to define the natural history of nerve conduction studies in Guillain-Barré syndrome.

Bickerstaff brainstem encephalitis and Fisher syndrome: anti-GQ1b antibody syndrome

Shahrizaila N, Yuki N

J Neurol Neurosurg Psychiatry, 2013 May;84(5):576-83.

PMID: 22984203 DOI: 10.1136/jnnp-2012-302824

In the 1950s, Bickerstaff and Fisher independently described cases with a unique presentation of ophthalmoplegia and ataxia. The neurological features were typically preceded by an antecedent infection and the majority of patients made a spontaneous recovery. In the cases with Bickerstaff brainstem encephalitis, there was associated altered consciousness and in some, hyperreflexia, in support of a central pathology whereas in Fisher syndrome, patients were areflexic in keeping with a peripheral aetiology. However, both authors recognised certain similarities to Guillain-Barré syndrome such as the presence of peripheral neuropathy and cerebrospinal fluid albuminocytological dissociation. The discovery of immunoglobulin G anti-GQ1b antibodies in patients with Fisher syndrome and later in Bickerstaff brainstem encephalitis was crucial in providing the necessary evidence to conclude that both conditions were in fact part of the same spectrum of disease by virtue of their common clinical and immunological profiles. Following this, other neurological presentations that share anti-GQ1b antibodies emerged in the literature. These include acute ophthalmoparesis and acute ataxic neuropathy, which represent the less extensive spectrum of the disease whereas pharyngeal-cervical-brachial weakness and Fisher syndrome overlap with Guillain-Barré syndrome represent the more extensive end of the spectrum. The conditions can be referred to as the 'anti-GQ1b antibody syndrome'. In this review, we look back at the historical descriptions and describe how our understanding of Fisher syndrome and Bickerstaff brainstem encephalitis has evolved from their initial descriptions more than half a century ago.

Antiganglioside antibodies in Guillain-Barré syndrome and its related conditions

Shahrizaila N, Yuki N

Expert Rev Neurother, 2011 Sep;11(9):1305-13.

PMID: 21864076 DOI: 10.1586/ern.11.114

Guillain-Barré syndrome (GBS) is typically classified into two major subtypes: acute inflammatory demyelinating neuropathy and acute motor axonal neuropathy. Its most recognizable variant is Fisher syndrome. The last two decades have seen considerable advances in our understanding of GBS. Of note, various autoantibodies against ganglioside antigens have been identified and found to have significant associations with the axonal forms of GBS and Fisher syndrome. In this article, we discuss the different clinical presentations in GBS and the role of antiganglioside antibodies in their underlying pathogenesis. We also discuss the impact that antiganglioside antibodies have had in the development of experimental models and treatment modalities in GBS.

Serial nerve conduction studies provide insight into the pathophysiology of Guillain-Barré and Fisher syndromes

Shahrizaila N, Goh KJ, Kokubun N, Abdullah S, Yuki N

J Neurol Sci, 2011 Oct 15;309(1-2):26-30.

PMID: 21849173 DOI: 10.1016/j.jns.2011.07.042

The electrodiagnosis of Guillain-Barré syndrome (GBS) can be broadly divided into acute inflammatory demyelinating polyneuropathy (AIDP) and acute motor axonal neuropathy (AMAN). Fisher syndrome (FS) is a variant of GBS, although the underlying neuropathy of FS has yet to be established. Serial nerve conduction studies (NCS) can provide further insight into the likely pathophysiology by further subtyping of GBS and FS. We present a patient with an initial diagnosis of AIDP in whom repeated NCS revealed the AMAN variant. This led us to investigate serial NCS in five patients with GBS, FS and FS/GBS overlap presenting over a period of a year. Three patients with AIDP showed a gradual increase in distal motor latencies during the acute phase of illness. NCS of two patients with FS and FS/GBS overlap showed no demyelinating features suggesting underlying axonal neuropathy in this group of patients. The importance of serial NCS in establishing the underlying pattern of neuropathy in GBS and FS is further emphasized in this study. Larger studies incorporating serial NCS are required to confirm the observations seen in our case series especially when pathological studies are often not justified in this group of patients.

The role of immunotherapy in Guillain-Barré syndrome: understanding the mechanism of action

Shahrizaila N, Yuki N

Expert Opin Pharmacother, 2011 Jul;12(10):1551-60.

PMID: 21473704 DOI: 10.1517/14656566.2011.564160

Guillain-Barré syndrome (GBS) is the most frequent cause of acute flaccid paralysis and, despite treatment, there continues to be an associated mortality and severe disability ranging from 9 to 17%. This article reviews the rationale behind the existing immunotherapy in GBS and discusses the future direction that work in this area should follow.

Two sets of nerve conduction studies may suffice in reaching a reliable electrodiagnosis in Guillain-Barré syndrome

Shahrizaila N, Goh KJ, Abdullah S, Kuppusamy R, Yuki N

Clin Neurophysiol, 2013 Jul;124(7):1456-9.

PMID: 23395599 DOI: 10.1016/j.clinph.2012.12.047

Recent studies have advocated the use of serial nerve conduction studies (NCS) in the electrodiagnosis of Guillain-Barré syndrome (GBS). The current study aims to elucidate when and how frequent NCS can be performed to reflect the disease pathophysiology.

Anti-GQ1b antibody syndrome: anti-ganglioside complex reactivity determines clinical spectrum

Fukami Y, Wong AH, Funakoshi K, Safri AY, Shahrizaila N, Yuki N

Eur J Neurol, 2016 Feb;23(2):320-6.

PMID: 26176883 DOI: 10.1111/ene.12769

Anti-GQ1b antibodies have been found in patients with Miller Fisher syndrome as well as its related conditions. Our aim was to identify the mechanism by which autoantibodies produce various clinical presentations in 'anti-GQ1b antibody syndrome'.

Complement regulatory proteins (CD46, 55 and 59) expressed on Schwann cells: immune targets in demyelinating neuropathies?

Miyaji K, Paul F, Shahrizaila N, Umapathi T, Yuki N

J Neuroimmunol, 2014 Nov 15;276(1-2):172-4.

PMID: 25156074 DOI: 10.1016/j.jneuroim.2014.08.004

Given their localization and important role in regulating complement, complement regulatory proteins may act as target antigens and their antibodies as biomarkers in demyelinating neuropathies. We investigated the binding of autoantibodies to complement regulatory proteins (CD46, 55 and 59) in demyelinating diseases. In 42 acute inflammatory demyelinating polyneuropathy, 23 chronic inflammatory demyelinating polyneuropathy, 13 acute motor axonal neuropathy, 71 multiple sclerosis, and 19 neuromyelitis optica patients as well as 55 healthy controls, we were unable to detect significant titers of antibodies to CD46, CD55 and CD59. These autoantibodies are unlikely to be biomarkers in acute and chronic inflammatory demyelinating polyneuropathies.

Autoantibodies to tetraspanins (CD9, CD81 and CD82) in demyelinating diseases

Miyaji K, Paul F, Shahrizaila N, Umapathi T, Yuki N

J Neuroimmunol, 2016 Feb 15;291:78-81.

PMID: 26857499 DOI: 10.1016/j.jneuroim.2015.12.012

Tetraspanin family proteins, CD9, CD81 and CD82 are expressed in the oligodendrocytes and Schwann cells. We investigated autoantibodies to tetraspanin proteins in patients with demyelinating diseases. Sera were collected from 119 multiple sclerosis patients, 19 neuromyelitis optica, 42 acute inflammatory demyelinating polyneuropathy, 23 chronic inflammatory demyelinating polyneuropathy and 13 acute motor axonal neuropathy as well as 55 healthy controls. Few multiple sclerosis and acute inflammatory demyelinating polyneuropathy patients had autoantibodies that were weakly reactive to CD9 or CD81 but the significance is unclear. It is unlikely that these autoantibodies are pathogenic or serve as potential biomarkers in demyelinating diseases.

Electrodiagnosis of reversible conduction failure in Guillain-Barré syndrome

Chan YC, Punzalan-Sotelo AM, Kannan TA, Shahrizaila N, Umapathi T, Goh EJH, et al.

Muscle Nerve, 2017 Nov;56(5):919-924.

PMID: 28093784 DOI: 10.1002/mus.25577

INTRODUCTION: In this study we propose electrodiagnostic criteria for early reversible conduction failure (ERCF) in axonal Guillain-Barré syndrome (GBS) and apply them to a cohort of GBS patients.

METHODS: Serial nerve conduction studies (NCS) were retrospectively analyzed in 82 GBS patients from 3 centers. The criteria for the presence of ERCF in a nerve were: (i) a 50% increase in amplitude of distal compound muscle action potentials or sensory nerve action potentials; or (ii) resolution of proximal motor conduction block with an accompanying decrease in distal latencies or compound muscle action potential duration or increase in conduction velocities.

RESULTS: Of 82 patients from 3 centers, 37 (45%) had ERCF, 21 (26%) had a contrasting evolution pattern, and 8 (10%) had both. Sixteen patients did not show an amplitude increase of at least 50%.

CONCLUSION: Our proposed criteria identified a group of patients with a characteristic evolution of NCS abnormality that is consistent with ERCF. Muscle Nerve 56: 919-924, 2017.

Fulltext Guillain-barré syndrome animal model: the first proof of molecular mimicry in human autoimmune disorder

Shahrizaila N, Yuki N

J Biomed Biotechnol, 2011;2011:829129.

PMID: 21197269 DOI: 10.1155/2011/829129

Molecular mimicry between self and microbial components has been proposed as the pathogenic mechanism of autoimmune diseases, and this hypothesis is proven in Guillain-Barré syndrome. Guillain-Barré syndrome, the most frequent cause of acute neuromuscular paralysis, sometimes occurs after Campylobacter jejuni enteritis. Gangliosides are predominantly cell-surface glycolipids highly expressed in nervous tissue, whilst lipo-oligosaccharides are major components of the Gram-negative bacterium C. jejuni outer membrane. IgG autoantibodies to GM1 ganglioside were found in the sera from patients with Guillain-Barré syndrome. Molecular mimicry was demonstrated between GM1 and lipo-oligosaccharide of C. jejuni isolated from the patients. Disease models by sensitization of rabbits with GM1 and C. jejuni lipo-oligosaccharide were established. Guillain-Barré syndrome provided the first verification that an autoimmune disease is triggered by molecular mimicry. Its disease models are helpful to further understand the molecular pathogenesis as well as to develop new treatments in Guillain-Barré syndrome.

Guidelines for neuromuscular ultrasound training

Tawfik EA, Cartwright MS, Grimm A, Boon AJ, Kerasnoudis A, Preston DC, et al.

Muscle Nerve, 2019 10;60(4):361-366.

PMID: 31335971 DOI: 10.1002/mus.26642

Neuromuscular ultrasound has become an essential tool in the diagnostic evaluation of various neuromuscular disorders, and, as such, there is growing interest in neuromuscular ultrasound training. Effective training is critical in mastering this modality. Our aim was to develop consensus-based guidelines for neuromuscular ultrasound training courses. A total of 18 experts participated. Expert opinion was sought through the Delphi method using 4 consecutive electronic surveys. A high degree of consensus was achieved with regard to the general structure of neuromuscular ultrasound training; the categorization of training into basic, intermediate, and advanced levels; the learning objectives; and the curriculum for each level. In this study, a group of neuromuscular ultrasound experts established consensus-based guidelines for neuromuscular ultrasound training. These guidelines can be used in the development of the specialty and the standardization of neuromuscular ultrasound training courses and workshops.

Neuromuscular ultrasound competency assessment: Consensus-based survey

Tawfik EA, Cartwright MS, Grimm A, Boon AJ, Kerasnoudis A, Preston DC, et al.

Muscle Nerve, 2021 05;63(5):651-656.

PMID: 33382094 DOI: 10.1002/mus.27163

Neuromuscular ultrasound is a rapidly evolving specialty with direct application for patient care. Competency assessment is an essential standard needed to ensure quality for practitioners, particularly for those newly acquiring skills with the technique. Our aim was to survey experts' opinions regarding physician competency assessment of neuromuscular ultrasound and to identify minimal competency of knowledge and skills. The opinions of 18 experts were obtained through the Delphi method using two consecutive electronic surveys. A high degree of consensus was achieved on items regarding framework and the conduct of neuromuscular ultrasound assessment and the knowledge and skills that a candidate needs to attain minimal competency in neuromuscular ultrasound. In this study, a group of neuromuscular ultrasound experts developed a general framework for neuromuscular ultrasound competency assessment and recommended testable areas of knowledge and skills suitable for establishing minimal competency.

Neuromuscular ultrasound standardized scanning techniques and protocols: Expert panel recommendations

Tawfik EA, Cartwright MS, van Alfen N, Axer H, Boon AJ, Crump N, et al.

Muscle Nerve, 2023 Oct;68(4):375-379.

PMID: 37074101 DOI: 10.1002/mus.27830

Neuromuscular ultrasound has become an integral part of the diagnostic workup of neuromuscular disorders at many centers. Despite its growing utility, uniform standard scanning techniques do not currently exist. Scanning approaches for similar diseases vary in the literature creating heterogeneity in the studies as reported in several meta-analysis. Moreover, neuromuscular ultrasound experts including the group in this study have different views with regards to technical aspects, scanning protocols, and the parameters that should be assessed. Establishing standardized neuromuscular scanning protocols is essential for the development of the subspeciality to ensure uniform clinical and research practices. Therefore, we aimed to recommend consensus-based standardized scanning techniques and protocols for common neuromuscular disorders using the Delphi approach. A panel of 17 experts participated in the study, which consisted of three consecutive electronic surveys. The first survey included voting on six scanning protocols addressing the general scanning technique and five common categories of suspected neuromuscular disorders. The subsequent surveys focused on refining the protocols and voting on new steps, rephrased statements, or areas of non-agreement. A high degree of consensus was achieved on the general neuromuscular ultrasound scanning technique and the scanning protocols for focal mononeuropathies, brachial plexopathies, polyneuropathies, amyotophic lateral sclerosis, and muscle diseases. In this study, a group of neuromuscular ultrasound experts developed six consensus-based neuromuscular ultrasound scanning protocols that may serve as references for clinicians and researchers. The standardized protocols could also aid in achieving high-quality uniform neuromuscular ultrasound practices.

Neurophysiological and imaging biomarkers of lower motor neuron dysfunction in motor neuron diseases/amyotrophic lateral sclerosis: IFCN handbook chapter

Shin-Yi Lin C, Howells J, Rutkove S, Nandedkar S, Neuwirth C, Noto YI, et al.

Clin Neurophysiol, 2024 Mar 20;162:91-120.

PMID: 38603949 DOI: 10.1016/j.clinph.2024.03.015

This chapter discusses comprehensive neurophysiological biomarkers utilised in motor neuron disease (MND) and, in particular, its commonest form, amyotrophic lateral sclerosis (ALS). These encompass the conventional techniques including nerve conduction studies (NCS), needle and high-density surface electromyography (EMG) and H-reflex studies as well as novel techniques. In the last two decades, new methods of assessing the loss of motor units in a muscle have been developed, that are more convenient than earlier methods of motor unit number estimation (MUNE),and may use either electrical stimulation (e.g. MScanFit MUNE) or voluntary activation (MUNIX). Electrical impedance myography (EIM) is another novel approach for the evaluation that relies upon the application and measurement of high-frequency, low-intensity electrical current. Nerve excitability techniques (NET) also provide insights into the function of an axon and reflect the changes in resting membrane potential, ion channel dysfunction and the structural integrity of the axon and myelin sheath. Furthermore, imaging ultrasound techniques as well as magnetic resonance imaging are capable of detecting the constituents of morphological changes in the nerve and muscle. The chapter provides a critical description of the ability of each technique to provide neurophysiological insight into the complex pathophysiology of MND/ALS. However, it is important to recognise the strengths and limitations of each approach in order to clarify utility. These neurophysiological biomarkers have demonstrated reliability, specificity and provide additional information to validate and assess lower motor neuron dysfunction. Their use has expanded the knowledge about MND/ALS and enhanced our understanding of the relationship between motor units, axons, reflexes and other neural circuits in relation to clinical features of patients with MND/ALS at different stages of the disease. Taken together, the ultimate goal is to aid early diagnosis, distinguish potential disease mimics, monitor and stage disease progression, quantify response to treatment and develop potential therapeutic interventions.

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