Guillain-Barré syndrome in Eastern China: A study of 595 patients.

BACKGROUND AND PURPOSE: This study aimed to investigate geographical differences in the clinical features of Guillain-Barré syndrome (GBS) between patients from our region in Eastern China and patients from other areas. METHODS: A total of 595 patients fulfilling the diagnostic criteria ​for GBS or its variants were included from two large hospitals located in Eastern China. Data collection included demographics, antecedent events, clinical presentation and signs, electrophysiological subtypes, treatment, complications during hospitalization, clinical severity at nadir, and outcome at 12 months, and these data were compared to data from a study conducted in Southern China and the Europe/Americas section of the International GBS Outcome Study. RESULTS: The median (interquartile range) age of patients was 50 (36-61) years, the ratio of men to women was 1.2, and 49% of patients had antecedent events. Patients in our region of Eastern China had pure motor predominant GBS (158/340, 46%) and 30% (103/340) had complications during hospitalization. Patients aged over 60 years had a lower frequency of antecedent infections and single, axonal subtypes, but higher disability scores at entry, nadir, and 12 months. When compared with the Europe/Americas data, our patients had a lower frequency of antecedent infection (46% vs. 63%), cranial nerve involvement (43% vs. 49%), sensory deficits (45% vs. 69%), pain (19% vs. 57%) and mechanical ventilation (11% vs. 17%), but a higher frequency of axonal subtype (35% vs. 6%). There was a higher frequency of patients with antecedent gastroenteritis (16% vs. 8%), mechanical ventilation (11% vs. 8%) and axonal subtypes (35% vs. 19%) in our region in Eastern China than in Southern China. CONCLUSIONS: Patients with GBS in Eastern China showed significant clinical heterogeneity and differences when compared to other geographic areas.

On-Membrane Dynamic Interplay between Anti-GM1 IgG Antibodies and Complement Component C1q.

Guillain-Barré syndrome, an autoimmune neuropathy characterized by acute limb weakness, is often preceded by Campylobacter jejuni infection. Molecular mimicry exists between the bacterial lipo-oligosaccharide and human ganglioside. Such C. jejuni infection induces production of immunoglobulin G1 (IgG1) autoantibodies against GM1 and causes complement-mediated motor nerve injury. For elucidating the molecular mechanisms linking autoantigen recognition and complement activation, we characterized the dynamic interactions of anti-GM1 IgG autoantibodies on ganglioside-incorporated membranes. Using high-speed atomic force microscopy, we found that the IgG molecules assemble into a hexameric ring structure on the membranes depending on their specific interactions with GM1. Complement component C1q was specifically recruited onto these IgG rings. The ring formation was inhibited by an IgG-binding domain of staphylococcal protein A bound at the cleft between the CH2 and CH3 domains. These data indicate that the IgG assembly is mediated through Fc-Fc interactions, which are promoted under on-membrane conditions due to restricted translational diffusion of IgG molecules. Reduction and alkylation of the hinge disulfide impaired IgG ring formation, presumably because of an increase in conformational entropic penalty. Our findings provide mechanistic insights into the molecular processes involved in Guillain-Barré syndrome and, more generally, into antigen-dependent interplay between antibodies and complement components on membranes.

Acute painful autoimmune neuropathy: A variant of Guillain-Barré syndrome.

INTRODUCTION: We present a painful small-fiber neuropathy variant of Guillain-Barré syndrome characterized by antecedent infectious symptoms, hyporeflexia, and albuminocytologic dissociation. METHODS: Two patients received intravenous immunoglobulin, one corticosteroids. RESULTS: The patients subsequently improved. Immunoglobulin G (IgG) antibodies in their acute phase sera strongly bound to murine small nerve fibers, and the binding disappeared during the convalescent phase. Serum transfer to a murine nociceptive model induced transient alteration in thermal pain responses. DISCUSSION: Our case series suggest that an acute transient immune response can be directed against small nerve fibers, and that patients so affected can exhibit features of Guillain-Barré syndrome. Muscle Nerve 57: 320-324, 2018.

Autoantibodies to nodal isoforms of neurofascin in chronic inflammatory demyelinating polyneuropathy.

Chronic inflammatory demyelination polyneuropathy is a heterogeneous and treatable immune-mediated disorder that lacks biomarkers to support diagnosis. Recent evidence indicates that paranodal proteins (contactin 1, contactin-associated protein 1, and neurofascin-155) are the targets of autoantibodies in subsets of patients showing distinct clinical presentations. Here, we identified neurofascin-186 and neurofascin-140 as the main targets of autoantibodies in five patients presenting IgG reactivity against the nodes of Ranvier. Four patients displayed predominantly IgG4 antibodies, and one patient presented IgG3 antibodies that activated the complement pathway in vitro. These patients present distinct clinical features compared to those with anti-neurofascin-155 IgG4. Most patients had a severe phenotype associated with conduction block or decreased distal motor amplitude. Four patients had a subacute-onset and sensory ataxia. Two patients presented with nephrotic syndromes and one patient with an IgG4-related retroperitoneal fibrosis. Intravenous immunoglobulin and corticosteroids were effective in three patients, and one patient remitted following rituximab treatment. Clinical remission was associated with autoantibody depletion and with recovery of conduction block and distal motor amplitude suggesting a nodo-paranodopathy. Our data demonstrate that the pathogenic mechanisms responsible for chronic inflammatory demyelination polyneuropathy are broad and may include dysfunctions at the nodes of Ranvier in a subgroup of patients.

Paraparetic Guillain-Barré syndrome: Nondemyelinating reversible conduction failure restricted to the lower limbs.

INTRODUCTION: Paraparetic Guillain-Barré syndrome (GBS) is a rare subtype of GBS characterized by leg weakness and areflexia in the absence of neurological involvement of the arms, cranial nerves, or respiratory muscles. Onset is characterized by lower back, buttock, or leg pain, followed by development of symmetric flaccid limb weakness in the absence of sensory disturbance. METHODS: We describe an elderly woman who developed postinfectious symmetric flaccid leg weakness in the absence of sensory disturbance. Serial nerve conduction studies were carried out over 5 months. RESULTS: Antecedent infection, a monophasic disease course, and the presence of cerebrospinal fluid albuminocytological dissociation suggested a diagnosis of paraparetic GBS. Serial nerve conduction studies demonstrated nondemyelinating reversible conduction failure, which was restricted to the legs. Axonal neuropathy was supported by the presence of anti-GM1 IgG antibodies. CONCLUSIONS: These findings suggest that patients with paraparetic GBS have axonal neuropathy, which is restricted to the lower limbs. Muscle Nerve 55: 281-285, 2017.

Electrodiagnosis of reversible conduction failure in Guillain-Barré syndrome.

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.

Using Xenopus tissue cultures for the study of myasthenia gravis pathogenesis.

Myasthenia gravis (MG), the most common autoimmune disease of neuromuscular junction (NMJ), is heterogeneous in terms of pathophysiology, which is determined by the pathogenic antigen of autoantibodies targeting to synaptic proteins at the NMJs. Currently, patients suspected with MG are routinely screened for the presence of autoantibodies against acetylcholine receptor (AChR) or muscle-specific kinase (MuSK) using a cell-based assay (CBA) that involves the expression of target synaptic membrane protein in heterologous cell lines. However, some autoantibodies may only show reactivity for binding to densely clustered AChR in the physiological conformation, while AChR clustering is known to involve signaling events orchestrated by over a dozen of postsynaptic proteins. To improve the existing serological diagnosis of MG, this study explored the possibility of using the well-established Xenopus primary culture system as a novel CBA for MG. Here, by examining the pathogenic effects of four MG human plasma samples, we found that the samples from both seropositive and seronegative MG patients effectively induced the disassembly of aneural AChR clusters in cultured Xenopus muscle cells, as well as the nerve-induced AChR clusters in the nerve-muscle co-cultures. Importantly, the disassembly of AChR clusters was spatio-temporally correlated to the disappearance of actin depolymerizing factor (ADF)/cofilin, an actin regulator involved in AChR trafficking and clustering. Taken together, this study develops a reliable CBA using Xenopus primary cultures for screening the pathogenicity of human MG plasma samples, and providing a platform for investigating the pathogenic mechanisms underlying the endocytic trafficking and degradation of AChRs at NMJs in MG patients.

An animal model of Miller Fisher syndrome: Mitochondrial hydrogen peroxide is produced by the autoimmune attack of nerve terminals and activates Schwann cells.

The neuromuscular junction is a tripartite synapse composed of the presynaptic nerve terminal, the muscle and perisynaptic Schwann cells. Its functionality is essential for the execution of body movements and is compromised in a number of disorders, including Miller Fisher syndrome, a variant of Guillain-Barré syndrome: this autoimmune peripheral neuropathy is triggered by autoantibodies specific for the polysialogangliosides GQ1b and GT1a present in motor axon terminals, including those innervating ocular muscles, and in sensory neurons. Their binding to the presynaptic membrane activates the complement cascade, leading to a nerve degeneration that resembles that caused by some animal presynaptic neurotoxins. Here we have studied the intra- and inter-cellular signaling triggered by the binding and complement activation of a mouse monoclonal anti-GQ1b/GT1a antibody to primary cultures of spinal cord motor neurons and cerebellar granular neurons. We found that a membrane attack complex is rapidly assembled following antibody binding, leading to calcium accumulation, which affects mitochondrial functionality. Consequently, using fluorescent probes specific for mitochondrial hydrogen peroxide, we found that this reactive oxygen species is rapidly produced by mitochondria of damaged neurons, and that it triggers the activation of the MAP kinase pathway in Schwann cells. These results throw light on the molecular and cellular pathogenesis of Miller Fisher syndrome, and may well be relevant to other pathologies of the motor axon terminals, including some subtypes of the Guillain Barré syndrome.

Sialylated IgG-Fc: a novel biomarker of chronic inflammatory demyelinating polyneuropathy.

OBJECTIVE: Sialylation in Fc portion of IgG plays a crucial role in the pathogenesis of autoimmune diseases and the working mechanism of intravenous immunoglobulin (IVIG). We aim to test whether IgG-Fc sialylation is a biomarker of disease activity for chronic inflammatory demyelinating polyneuropathy (CIDP). METHODS: By using specific lectins for sialylation, galactosylation and agalactosylation, lectin-enzyme assay and lectin blotting with pretreatment of IgG degradating enzyme of Streptococcus pyogenes were performed to compare the glycosylation levels of serum IgG-Fc (1) between patients of untreated CIDP (n=107) and normal control subjects (n=27), (2) among patients with untreated CIDP of different clinical severities and (3) before and after IVIG treatment of patients with CIDP (n=12). RESULTS: Sialylation and galactosylation of IgG-Fc were significantly reduced in patients with CIDP than normal control subjects (p=0.003 and 0.033, respectively), whereas agalactosylation was increased in CIDP (p=0.21). Ratios of sialylated/agalactosylated IgG-Fc levels were significantly reduced in CIDP (p<0.001) and inversely related to disease severity (p=0.044). After IVIG treatment, levels of sialylated IgG-Fc significantly increased (p=0.003). CONCLUSIONS: Sialylation of IgG-Fc is reduced in CIDP. Its level correlated with clinical severity and increased after IVIG treatment. Sialylated as well as ratio of sialylated/agalactosylated IgG-Fc could be new measures to monitor the disease severity and treatment status in CIDP.

Consensus Paper: Neuroimmune Mechanisms of Cerebellar Ataxias.

In the last few years, a lot of publications suggested that disabling cerebellar ataxias may develop through immune-mediated mechanisms. In this consensus paper, we discuss the clinical features of the main described immune-mediated cerebellar ataxias and address their presumed pathogenesis. Immune-mediated cerebellar ataxias include cerebellar ataxia associated with anti-GAD antibodies, the cerebellar type of Hashimoto's encephalopathy, primary autoimmune cerebellar ataxia, gluten ataxia, Miller Fisher syndrome, ataxia associated with systemic lupus erythematosus, and paraneoplastic cerebellar degeneration. Humoral mechanisms, cell-mediated immunity, inflammation, and vascular injuries contribute to the cerebellar deficits in immune-mediated cerebellar ataxias.

Acute bulbar, neck and limb weakness with monospecific anti-GT1a antibody: A rare localized subtype of Guillain-Barré syndrome.

INTRODUCTION: Acute bulbar, neck, and limb weakness carries several potential differential diagnoses. Although a diagnosis can often be established clinically, investigations such as electrodiagnostic and antibody testing can provide support for the clinical diagnosis and may aid in understanding the pathogenesis. A 65-year-old woman presented with acute bulbar, neck, and rapidly progressive bilateral upper limb weakness. METHODS: Clinical evaluation, electrophysiological, and serological studies were undertaken. RESULTS: Neurophysiology demonstrated proximal conduction block. A clinical diagnosis of pharyngeal-cervical-brachial weakness, a localized variant of Guillain-Barré syndrome, was made. The patient received treatment with intravenous immunoglobulin and made a remarkable recovery over the next month. She was found to have serum monospecific anti-GT1a antibodies. CONCLUSIONS: We report a case of pharyngeal-cervical-brachial weakness with monospecific anti-GT1a antibodies and discuss the differential diagnosis of acute bulbar, neck, and limb weakness.

Contactin 1 IgG4 associates to chronic inflammatory demyelinating polyneuropathy with sensory ataxia.

A Spanish group recently reported that four patients with chronic inflammatory demyelinating polyneuropathy carrying IgG4 autoantibodies against contactin 1 showed aggressive symptom onset and poor response to intravenous immunoglobulin. We aimed to describe the clinical and serological features of Japanese chronic inflammatory demyelinating polyneuropathy patients displaying the anti-contactin 1 antibodies. Thirteen of 533 (2.4%) patients with chronic inflammatory demyelinating polyneuropathy had anti-contactin 1 IgG4 whereas neither patients from disease or normal control subjects did (P = 0.02). Three of 13 (23%) patients showed subacute symptom onset, but all of the patients presented with sensory ataxia. Six of 10 (60%) anti-contactin 1 antibody-positive patients had poor response to intravenous immunoglobulin, whereas 8 of 11 (73%) antibody-positive patients had good response to corticosteroids. Anti-contactin 1 IgG4 antibodies are a possible biomarker to guide treatment option.

Paediatric brainstem encephalitis associated with glial and neuronal autoantibodies.

AIM: Central nervous system (CNS) autoantibodies have been reported in a range of neuroimmune diseases, but there has not been a systematic evaluation of autoantibodies in paediatric patients with brainstem encephalitis. METHOD: Serum samples from 57 children (40 male, 17 female, median age 12y, range 0.6-18y) with a diagnosis of brainstem encephalitis were tested retrospectively for antibodies to GQ1b, aquaporin-4 (AQP4), myelin oligodendrocyte glycoprotein (MOG), N-methyl-D-aspartate receptor, LGI1, CASPR2, glycine receptor (GlyR), DPPX, and the voltage gated potassium channel (VGKC)-complex. RESULTS: Disease localized to the brainstem was seen in 19 patients: Bickerstaff's brainstem encephalitis (n=14) and clinically isolated syndrome (n=5). Polyfocal presentation was seen in 38 children, with predominantly white matter disease in 18 patients and grey matter in 20 patients. CNS surface antibodies were found in 22/57 patients (two patients with double positivity): GQIb (n=6), NMDAR (n=7), GlyR (n=5), MOG (n=5), and one AQP4. Three patients were positive for VGKC-complex antibodies. All patients were negative for antibodies to DPPX and the VGKC-complex antigens LGI1, CASPR2, and contactin-2. Although there were some partial differences in the presentations, the clinical features and outcomes did not relate clearly to the presence or absence of specific antibodies. INTERPRETATION: As determined retrospectively, 39% of patients had cell surface antibodies. The results did not suggest any relationship with treatment or outcomes obtained but it is possible that specific antibody detection could be a helpful guide to more intensive immunotherapies in some cases.

Autoimmune inflammatory neuropathies: updates in pathogenesis, diagnosis, and treatment.

PURPOSE OF REVIEW: The present review aims at discussing the recent advances in pathogenesis, diagnosis, and treatment of major subtypes of autoimmune inflammatory neuropathies. RECENT FINDINGS: Concerning pathogenesis, further evidence has proved that antibodies to nodal proteins are pathogenic in inflammatory neuropathies. The presence of these antibodies is related to distinctive clinical features. Disruption of blood-nerve barrier mediated by cytokines and chemokines also plays an important role in the pathogenesis. The new terminology of 'nodopathies' describes immune-mediated attack beginning and limited to the nodal region, and this phenomenon can be found in both acute and chronic inflammatory neuropathies. Recent trials comparing intravenous and subcutaneous immunoglobulin confirm that subcutaneous immunoglobulin is not only cost-effective, but also improves patients' satisfaction and quality of life compared to intravenous immunoglobulin. Although immunotherapies are effective in most of the inflammatory neuropathies, accurate predictors and biomarkers of treatment response are lacking. Moreover, some patients do not respond to current immunotherapies and continue to relapse after discontinuation of treatment. SUMMARY: More studies are required to understand the exact antigenic targets and mechanism in inflammatory neuropathies, so as to develop more novel immunotherapies.

Isolated facial diplegia in Guillain-Barré syndrome: Bifacial weakness with paresthesias.

Bifacial weakness with paresthesias (BFP) is a subtype of Guillain-Barré syndrome defined by rapidly progressive bilateral facial weakness in the absence of other cranial neuropathies, ataxia, or limb weakness. Many patients also complain of distal limb paresthesias and display diminished or absent deep tendon reflexes. BFP is a localized form of Guillain-Barré syndrome and is thought to be caused exclusively by demyelinating- rather than axonal-type neuropathy. Patients with BFP do not display anti-ganglioside IgG antibodies. Since it is rare, many physicians are unfamiliar with BFP, as bilateral facial weakness is more commonly associated with sarcoidosis, Lyme disease, or meningeal pathology. Many patients diagnosed with bilateral Bell palsy may instead have BFP. In this review, we highlight the clinical features of BFP and outline diagnostic criteria.

Delayed facial weakness in Guillain-Barré and Miller Fisher syndromes.

INTRODUCTION: Dr. C. Miller Fisher described the appearance of unilateral facial palsy after resolution of ataxia in a patient with the eponymic Miller Fisher syndrome (MFS). However, there have been very few reports of delayed appearance of facial weakness in Guillain-Barré syndrome (GBS) and MFS when the other neurological signs reached nadir or started improving. METHODS: In this study we reviewed the clinical and laboratory findings of consecutive patients with GBS (n=195) and MFS (n=68). RESULTS: Delayed facial weakness occurred in 12 (6%) GBS and 4 (6%) MFS patients and was unilateral in 5 (42%) GBS and 2 (50%) MFS patients. In those patients with delayed facial weakness, neither limb weakness nor ataxia progressed, and facial weakness disappeared without immunotherapy. CONCLUSIONS: Because facial weakness can lead to further morbidity, it would be prudent for clinicians to warn patients of this possibility, although additional immunotherapy is usually not required.

Proximal conduction block in the pharyngeal-cervical-brachial variant of Guillain-Barré syndrome.

INTRODUCTION: Conduction block (CB) has been included in the Rajabally criteria for axonal Guillain-Barré syndrome (GBS). Because the nerve roots may be affected early in GBS, detection of proximal CB by the triple stimulation technique (TST) can be useful. METHODS: We describe TST findings in 2 patients who presented with the pharyngeal-cervical-brachial (PCB) variant of axonal GBS. RESULTS: In the first patient, although conventional nerve conduction studies (NCS) did not fit electrodiagnostic criteria for axonal GBS, the TST detected proximal CB in the median and ulnar nerves. In the second patient, NCS fulfilled criteria for axonal GBS, and the TST detected proximal CB in the median nerve. After plasmapheresis, NCS and TST findings were normalized, suggesting reversible conduction failure rather than demyelinating CB. CONCLUSION: The TST may be useful for diagnosis of PCB when NCS remain inconclusive. The technique provides additional clues for classifying PCB into the acute nodo-paranodopathies.

Cytoalbuminologic dissociation in Asian patients with Guillain-Barré and Miller Fisher syndromes.

Cerebrospinal fluid (CSF) protein level, cell count, and its relationship to the timing of lumbar puncture were collected from patients with Guillain-Barré syndrome (GBS) and Miller Fisher syndrome (MFS) from various Asian centers. A total of 507 patients with GBS were studied. Overall, 56% had elevated CSF protein level. This was significantly lower than that reported in a recent Dutch study (56% vs 64%). Cytoalbuminologic dissociation was also lower in the Asian cohort (55% vs 64%), with a significantly higher proportion of patients with mild pleocytosis (26% vs 15%). A lower proportion of the 164 patients with MFS had elevated CSF protein level (38% vs 56%), mild pleocytosis (11% vs 26%), and cytoalbuminologic dissociation (41% vs 55%) compared to patients with GBS. In both conditions, cytoalbuminologic dissociation was linked to the timing of lumbar puncture. Cytoalbuminologic dissociation was only observed in half of the Asian patients with GBS and MFS, and it is strongly dependent on the timing of the lumbar puncture.

Mimics and chameleons in Guillain-Barré and Miller Fisher syndromes.

Guillain-Barré syndrome (GBS) and its variant, Miller Fisher syndrome (MFS) have several subtypes, together forming a continuous spectrum of discrete and overlapping syndromes. Such is the heterogeneity within this spectrum that many physicians may be surprised to learn that these disorders are related pathophysiologically, and therefore share certain clinical features. These include history of antecedent infection, monophasic disease course and symmetrical cranial or limb weakness. The presence of cerebrospinal fluid albuminocytological dissociation (raised protein, normal cell count), antiganglioside antibodies and neurophysiological evidence of axonal or demyelinating neuropathy also support a diagnosis in many cases, but should not be relied upon. Mimics of GBS and MFS can broadly be divided into those presenting with symmetrical limb weakness and those presenting with brainstem signs. MFS and the pharyngeal-cervical-brachial variant of GBS are frequently mistaken for brainstem stroke, botulism or myasthenia gravis, whereas Bickerstaff's brainstem encephalitis is often diagnosed as Wernicke's encephalopathy. Chameleons or atypical presentations of GBS-related disorders include: paraparetic GBS, bifacial weakness with paraesthesias, acute ataxic neuropathy, acute ophthalmoparesis, acute ptosis and acute mydriasis. Many neurologists may also not be aware that deep tendon reflexes remain present or may even appear brisk in up to 10% of patients with GBS. Correct diagnosis of GBS-related disorders helps to avoid unnecessary investigations and allows early immunotherapy if appropriate.