Antibodies to heteromeric glycolipid complexes in Guillain-Barré syndrome

Guillain-Barré syndrome: History, pathogenesis, treatment, and future directions

BACKGROUND AND PURPOSE

Since its description by Guillain, Barré, and Strohl in 1916, Guillain-Barré syndrome (GBS) has attracted a large literature. The author reviews the history of research into its pathogenesis and treatment to highlight promising avenues for future research.

METHODS

This is a nonsystematic personal review.

RESULTS

Since the early 1900s, the clinical picture of GBS has been illustrated in multiple series culminating in the ongoing International Guillain-Barré Syndrome study of 2000 patients. In the 1950s and 1960s, the inflammatory nature of the commonest form, acute inflammatory demyelinating polyradiculoneuropathy (AIDP), was described. In the 1990s, two axonal forms, acute motor-sensory axonal neuropathy and acute motor axonal neuropathy, were recognized. In the 1990s and early 2000s, these forms were shown to be due to antibodies against Campylobacter jejuni glycans cross-reacting with glycolipids on axonal membranes. The pathogenesis of AIDP remains unknown, but T-cell responses to the compact myelin proteins, P2 and P0, which cause experimental autoimmune neuritis, suggest that T cells are important. Randomized controlled trials in the 1970s and 1980s showed no benefit from corticosteroids. Trials in the 1980s showed benefit from plasma exchange and in the 1990s from intravenous immunoglobulin.

CONCLUSIONS

Future research should seek biomarkers to identify subgroups with different treatment responses, define the true natural history of the disease with population-based epidemiological studies, study the pathology in autopsies early in the disease, seek causative antibodies and confirm autoimmune T-cell responses in AIDP, and expand treatment trials to include anti-T-cell agents.

Expanding our understanding of Guillain-Barré syndrome: Recent advances and clinical implications

Guillain-Barré syndrome (GBS) is a rare yet potentially life-threatening disorder of the peripheral nervous system (PNS), characterized by substantial clinical heterogeneity. Although classified as an autoimmune disease, the immune mechanisms underpinning distinct GBS subtypes remain largely elusive. Traditionally considered primarily antibody-mediated, the pathophysiology of GBS lacks clarity, posing challenges in the development of targeted and effective treatments. Nevertheless, recent investigations have substantially expanded our understanding of the disease, revealing an involvement of autoreactive T cell immunity in a major subtype of GBS patients and opening new biomedical perspectives. This review highlights these discoveries and offers a comprehensive overview of current knowledge about GBS, including ongoing challenges in disease management.

Guillain-Barré syndrome: a comprehensive review

Guillain-Barré syndrome (GBS) is a potentially devastating yet treatable disorder. A classically postinfectious, immune-mediated, monophasic polyradiculoneuropathy, it is the leading global cause of acquired neuromuscular paralysis. In most cases, the immunopathological process driving nerve injury is ill-defined. Diagnosis of GBS relies on clinical features, supported by laboratory findings and electrophysiology. Although previously divided into primary demyelinating or axonal variants, this dichotomy is increasingly challenged, and is not endorsed by the recent European Academy of Neurology (EAN)/Peripheral Nerve Society (PNS) guidelines. Intravenous immunoglobulin and plasma exchange remain the primary modalities of treatment, regardless of the electrophysiological subtype. Most patients recover, but approximately one-third require mechanical ventilation, and 5% die. Disease activity and treatment response are currently monitored through interval neurological examination and outcome measures, and the potential role of fluid biomarkers is under ongoing scrutiny. Novel potential therapies for GBS are being explored but none have yet modified clinical practice. This review provides a comprehensive update on the pathological and clinical aspects of GBS for clinicians and scientists.

Guillain-Barre syndrome following scrub typhus: a case report and literature review

BACKGROUND

Scrub typhus is an acute infectious disease caused by Orientia tsutsugamushi. Guillain-Barre syndrome (GBS) is an autoimmune-mediated peripheral neuropathy with a frequent history of prodromal infections, but GBS associated with scrub typhus is very rare.

CASE PRESENTATION

We report a 51-year-old male patient who developed dysarthria and peripheral facial paralysis following the cure of scfrub typhus. CSF examination and electrophysiological findings suggested a diagnosis of GBS. After treatment with intravenous immunoglobulin, the patient's neurological condition improved rapidly.

CONCLUSIONS

Scrub typhus infection is likely to be a potential predisposing factor in GBS, while scrub typhus-associated GBS has a favorable prognosis.

Anti-Glycolipid Antibody Examination in Five EAE Models and Theiler's Virus Model of Multiple Sclerosis: Detection of Anti-GM1, GM3, GM4, and Sulfatide Antibodies in Relapsing-Remitting EAE

Anti-glycolipid antibodies have been reported to play pathogenic roles in peripheral inflammatory neuropathies, such as Guillain-Barré syndrome. On the other hand, the role in multiple sclerosis (MS), inflammatory demyelinating disease in the central nervous system (CNS), is largely unknown, although the presence of anti-glycolipid antibodies was reported to differ among MS patients with relapsing-remitting (RR), primary progressive (PP), and secondary progressive (SP) disease courses. We investigated whether the induction of anti-glycolipid antibodies could differ among experimental MS models with distinct clinical courses, depending on induction methods. Using three mouse strains, SJL/J, C57BL/6, and A.SW mice, we induced five distinct experimental autoimmune encephalomyelitis (EAE) models with myelin oligodendrocyte glycoprotein (MOG)35-55, MOG92-106, or myelin proteolipid protein (PLP)139-151, with or without an additional adjuvant curdlan injection. We also induced a viral model of MS, using Theiler's murine encephalomyelitis virus (TMEV). Each MS model had an RR, SP, PP, hyperacute, or chronic clinical course. Using the sera from the MS models, we quantified antibodies against 11 glycolipids: GM1, GM2, GM3, GM4, GD3, galactocerebroside, GD1a, GD1b, GT1b, GQ1b, and sulfatide. Among the MS models, we detected significant increases in four anti-glycolipid antibodies, GM1, GM3, GM4, and sulfatide, in PLP139-151-induced EAE with an RR disease course. We also tested cellular immune responses to the glycolipids and found CD1d-independent lymphoproliferative responses only to sulfatide with decreased interleukin (IL)-10 production. Although these results implied that anti-glycolipid antibodies might play a role in remissions or relapses in RR-EAE, their functional roles need to be determined by mechanistic experiments, such as injections of monoclonal anti-glycolipid antibodies.

Guillain-Barre syndrome and pulmonary embolism in an adult female with COVID-19 infection in Ghana: A case report

INTRODUCTION

The coronavirus disease 2019 (COVID-19) pandemic began at the end of 2019 in Wuhan, the capital of Hubei Province, China. This novel coronavirus is classified as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Neurological manifestations are commonly associated with moderate to severe COVID-19 infection. Guillain-Barré syndrome (GBS) is a rare immune-mediated postinfectious neuropathy but there has been an increase in the number of cases of GBS associated with COVID-19, supporting the present body of global evidence of the notable association between the 2 conditions. We present the first proven case of GBS and pulmonary embolism associated with COVID-19 infection in Ghana, West Africa.

CASE PRESENTATION

A 60-year-old apparently healthy female presented in August 2020 to the COVID-19 treatment center of the Korle-Bu Teaching Hospital in Accra, Ghana from a referral facility following a week's history of low-grade fever, chills, rhinorrhoea, and generalized flaccid limb weakness. A positive SARS-CoV-2 test result was recorded 3 days after the onset of symptoms and the patient had no known chronic medical condition. Following cerebrospinal fluid analysis, neurophysiological studies and a chest computed tomography pulmonary angiogram, Guillain-Barre syndrome and pulmonary embolism were confirmed. The patient was however managed supportively and then discharged after 12 days on admission, as he made mild improvement in muscular power and function.

CONCLUSION

This case report adds to the body of evidence of the association between GBS and SARS-CoV-2 infection, particularly from West Africa. It further highlights the need to anticipate potential neurological complications of SARS-CoV-2, particularly GBS even in mild respiratory symptoms for prompt diagnosis and initiation of appropriate therapy to improve outcomes and avert long-term deficits.

A Rare Case of Guillain-Barré Syndrome Post-gastrojejunostomy and Literature Review

Guillain-Barré syndrome (GBS) is a rare immune-mediated neuropathy causing destruction of the peripheral nervous system, with molecular mimicry playing a major role in its pathophysiology. Despite its rarity, it is considered the most common cause of acute flaccid neuromuscular paralysis in the United States. Although diagnosing GBS depends on the clinical presentation of the patient, cerebrospinal fluid sampling, nerve conduction studies, electromyography, magnetic resonance imaging, and ganglioside antibody screening can be used to confirm the diagnosis and rule out other differentials. Here, we report a rare case of GBS as a postoperative complication after a successful gastrojejunostomy to excise an adenocarcinoma in the second part of the duodenum. Such a complication is rare and not fully understood yet.

Axolemmal nanoruptures arising from paranodal membrane injury induce secondary axon degeneration in murine Guillain-Barré syndrome

The major determinant of poor outcome in Guillain-Barré syndrome (GBS) is axonal degeneration. Pathways leading to primary axonal injury in the motor axonal variant are well established, whereas mechanisms of secondary axonal injury in acute inflammatory demyelinating polyneuropathy (AIDP) are unknown. We recently developed an autoantibody-and complement-mediated model of murine AIDP, in which prominent injury to glial membranes at the node of Ranvier results in severe disruption to paranodal components. Acutely, axonal integrity was maintained, but over time secondary axonal degeneration occurred. Herein, we describe the differential mechanisms underlying acute glial membrane injury and secondary axonal injury in this model. Ex vivo nerve-muscle explants were injured for either acute or extended periods with an autoantibody-and complement-mediated injury to glial paranodal membranes. This model was used to test several possible mechanisms of axon degeneration including calpain activation, and to monitor live axonal calcium signalling. Glial calpains induced acute disruption of paranodal membrane proteins in the absence of discernible axonal injury. Over time, we observed progressive axonal degeneration which was markedly attenuated by axon-specific calpain inhibition. Injury was unaffected by all other tested methods of protection. Trans-axolemmal diffusion of fluorescent proteins  and live calcium imaging studies indirectly demonstrated the presence of nanoruptures in the axon membrane. This study outlines one mechanism by which secondary axonal degeneration arises in the AIDP variant of GBS where acute paranodal loop injury is prominent. The data also support the development of calpain inhibitors to attenuate both primary and secondary axonal degeneration in GBS.

Guillain-Barré syndrome: expanding the concept of molecular mimicry

Guillain-Barré syndrome (GBS) is a rapidly progressive, monophasic, and potentially devastating immune-mediated neuropathy in humans. Preceding infections trigger the production of cross-reactive antibodies against gangliosides concentrated in human peripheral nerves. GBS is elicited by at least five distinct common bacterial and viral pathogens, speaking to the notion of polymicrobial disease causation. This opinion emphasizes that GBS is the best-supported example of true molecular mimicry at the B cell level. Moreover, we argue that mechanistically, single and multiplexed microbial carbohydrate epitopes induce IgM, IgA, and IgG subclasses in ways that challenge the classic concept of thymus-dependent (TD) versus thymus-independent (TI) antibody responses in GBS. Finally, we discuss how GBS can be exemplary for driving innovation in diagnostics and immunotherapy for other antibody-driven neurological diseases.

Detection of Autoantibodies Using Combinatorial Glycolipid Microarrays

Glycolipids cluster in plasma membranes to form heterogenous patches. Whereas lectins and antibodies have been conventionally viewed as binding a single oligosaccharide head group, and assayed accordingly, it is increasingly evident that cis-interactions between glycan headgroups may form unique molecular shapes that either enhance or attenuate binding of antibodies and other proteins. Herein we describe a method for assaying antibody binding to heteromeric glycolipid complexes that allows rapid, simple, inexpensive and high-throughput assessment of binding events, focusing on autoantibodies present in human serum.

Impact of antecedent infections on the antibodies against gangliosides and ganglioside complexes in guillain-barré syndrome: A correlative study

Background and Aims:

Guillain-Barré Syndrome (GBS), an immune-mediated neuropathy, is characterized by antibodies against gangliosides/ganglioside complexes (GSCs) of peripheral nerves. Antecedent infections have been reported to induce antibodies that cross-react with the host gangliosides and thereby have a pivotal role in conferring an increased risk for developing GBS. Data pertaining to the impact of various antecedent infections, particularly those prevalent in tropical countries like India on the ganglioside/GSC antibodies is sparse. We aimed at exploring the association between six antecedent infections and the profile of ganglioside/GSC antibodies in GBS.

Methods:

Patients with GBS (n = 150) and healthy controls (n = 50) were examined for the serum profile of antibodies against GM1, GM2, GD1a, GD1b, GT1b, and GQ1b and their GSCs by ELISA. These antibodies were correlated with immunoreactivities against Campylobacter jejuni, Japanese encephalitis (JE), dengue, influenza, zika, and chikungunya infections.

Results:

The frequencies of antibodies against six single gangliosides (P < 0.001) and their GSCs (P = 0.039) were significantly higher in patients as compared to controls. Except for GT1b-antibody which was more frequent in axonal GBS, none of the other ganglioside/GSC antibodies correlated with the electrophysiological subtypes of GBS. Antecedent JE infection was significantly associated with increased frequency of antibodies against GD1a, GD1b, GT1b, and GQ1b. Antibodies against GSCs were not influenced by the antecedent infections.

Interpretation:

This study for the first time shows an association between antecedent JE infection and ganglioside antibodies in GBS. This finding reinforces the determining role of antecedent infections on ganglioside antibody responses and the subsequent immunological processes in GBS.

Anti-ganglioside Antibodies in Guillain-Barre Syndrome: A Novel Immunoblotting-Panel Assay

Objective: This study aimed to determine the diagnostic efficiency of a novel immunoblotting detection assay for anti-ganglioside antibodies (AGAs) in the Guillain–Barre syndrome (GBS).

Method: Serum immunoglobulin (IgG and IgM) of AGAs were measured in 121 participants from a registered cohort study of immune-mediated neuropathies and 29 healthy controls by immunoblotting panel assay. Sensitivity, specificity, and positive predictive value (PPV) of the assay were compared to calculate the diagnostic accuracy.

Result: In our cohort, any of the AGAs were positive in 42.4% of the GBS patients. The sensitivity and specificity of AGAs (both IgG and IgM) in the diagnosis of GSB were 42 and 76% while for IgG-AGAs were 35 and 87%. AGAs positivity had a significant association with the AMAN subtype (P = 0.0004), and the sensitivity, specificity of AGAs in AMAN were 86, 69%, respectively with high (AUC = 0.78, p = 0.002) discriminative powers. GM1-IgG AGA was more common and specific to AMAN patients than other GBS forms (p = 0.008).

Conclusion: Our novel immunoblotting detection assay could complement GBS diagnosis. IgG-AGAs were more likely to be detected in GBS, and GM1-IgG AGA could assist AMAN diagnosis.

Biomolecule sulphation and novel methylations related to Guillain-Barré syndrome-associated Campylobacter jejuni serotype HS:19

Campylobacter jejuni strains that produce sialylated lipooligosaccharides (LOS) can cause the immune-mediated disease Guillain-Barré syndrome (GBS). The risk of GBS after infection with C. jejuni Penner serotype HS:19 is estimated to be at least six times higher than the average risk. Aside from LOS biosynthesis genes, genomic characteristics that promote an increased risk for GBS following C. jejuni HS:19 infection, remain uncharacterized. We hypothesized that strains with the HS:19 serotype have unique genomic features that explain the increased risk for GBS. We performed genome sequencing, alignments, single nucleotide polymorphisms' analysis and methylome characterization on a subset, and pan-genome analysis on a large number of genomes to compare HS:19 with non-HS:19 C. jejuni genome sequences. Comparison of 36 C. jejuni HS:19 with 874 C. jejuni non-HS:19 genome sequences led to the identification of three single genes and ten clusters containing contiguous genes that were significantly associated with C. jejuni HS:19. One gene cluster of seven genes, localized downstream of the capsular biosynthesis locus, was related to sulphation of biomolecules. This cluster also encoded the campylobacter sialyl transferase Cst-I. Interestingly, sulphated bacterial biomolecules such as polysaccharides can promote immune responses and, therefore, (in the presence of sialic acid) may play a role in the development of GBS. Additional gene clusters included those involved in persistence-mediated pathogenicity and gene clusters involved in restriction-modification systems. Furthermore, characterization of methylomes of two HS:19 strains exhibited novel methylation patterns (5′-CATG-3 and 5′-^m6AGTNNNNNNRTTG-3) that could differentially effect gene-expression patterns of C. jejuni HS:19 strains. Our study provides novel insight into specific genetic features and possible virulence factors of C. jejuni associated with the HS:19 serotype that may explain the increased risk of GBS.

Antecedent infections in Guillain-Barré syndrome in endemic areas of arbovirus transmission: A multinational case-control study

Half of the world's population is at risk of arthropod‐borne virus (arbovirus) infections. Several arbovirus infections have been associated with Guillain‐Barré syndrome (GBS). We investigated whether arboviruses are driving GBS beyond epidemic phases of transmission and studied the antibody response to glycolipids. The protocol of the International Guillain‐Barré syndrome Outcome Study (IGOS), an observational prospective cohort study, was adapted to a case‐control design. Serum samples were tested for a recent infection with Zika virus (ZIKV), dengue virus (DENV), chikungunya (CHIKV) virus, hepatitis E virus, Epstein‐Barr virus (EBV), cytomegalovirus (CMV), Campylobacter jejuni, and Mycoplasma pneumoniae, and for antibodies to glycolipids. Forty‐nine patients were included from Brazil (63%), Argentina (14%), and Malaysia (22%). Evidence of a recent infection was found in 27/49 (55%) patients: C jejuni (n = 15, 31%), M pneumoniae (n = 5, 10%), CHIKV (n = 2, 4%), EBV (n = 1, 2%), C jejuni and M pneumoniae (n = 2, 4%), CMV and DENV (n = 1, 2%), and C jejuni and DENV (n = 1, 2%). In 22 patients, 35 paired controls were collected. Odds ratio for recent infections did not significantly differ between cases and controls. No typical anti‐ganglioside antibody binding was associated with recent arbovirus infection. We conclude that arbovirus infections occur in GBS patients outside of epidemic viral transmission, although not significantly more than in controls. Broad infection and anti‐ganglioside antibody serology are important to establish the most likely pathogenic trigger in GBS patients. Larger studies are necessary to determine the association between arboviruses and GBS.

Elucidating autoimmune nodopathies and the CIDP spectrum

This scientific commentary refers to ‘Antibodies to the Caspr1/contactin-1 complex in chronic inflammatory demyelinating polyradiculoneuropathy’, by Pascual-Goñi et al. (doi:10.1093/brain/awab014).

Epidemiological and cohort study finds no association between COVID-19 and Guillain-Barré syndrome

Reports of Guillain-Barré syndrome (GBS) have emerged during the Coronavirus disease 2019 (COVID-19) pandemic. This epidemiological and cohort study sought to investigate any causative association between COVID-19 infection and GBS. The epidemiology of GBS cases reported to the UK National Immunoglobulin Database was studied from 2016 to 2019 and compared to cases reported during the COVID-19 pandemic. Data were stratified by hospital trust and region, with numbers of reported cases per month. UK population data for COVID-19 infection were collated from UK public health bodies. In parallel, but separately, members of the British Peripheral Nerve Society prospectively reported incident cases of GBS during the pandemic at their hospitals to a central register. The clinical features, investigation findings and outcomes of COVID-19 (definite or probable) and non-COVID-19 associated GBS cases in his cohort were compared. The incidence of GBS treated in UK hospitals from 2016 to 2019 was 1.65–1.88 per 100 000 individuals per year. In 2020, GBS and COVID-19 incidences varied between regions and did not correlate with one another (r = 0.06, 95% confidence interval: −0.56 to 0.63, P = 0.86). GBS incidence fell between March and May 2020 compared to the same months of 2016–19. In an independent cohort study, 47 GBS cases were reported (COVID-19 status: 13 definite, 12 probable, 22 non-COVID-19). There were no significant differences in the pattern of weakness, time to nadir, neurophysiology, CSF findings or outcome between these groups. Intubation was more frequent in the COVID-19 affected cohort (7/13, 54% versus 5/22, 23% in COVID-19-negative) likely related to COVID-19 pulmonary involvement. Although it is not possible to entirely rule out the possibility of a link this study finds no epidemiological or phenotypic clues of SARS-CoV-2 being causative of GBS. GBS incidence has fallen during the pandemic, which may be the influence of lockdown measures reducing transmission of GBS inducing pathogens such as Campylobacter jejuni and respiratory viruses.

Antiglycolipid antibodies in Guillain-Barré and Fisher syndromes: discovery, current status and future perspective

Guillain-Barré syndrome (GBS) and Fisher syndrome (FS) are acute autoimmune neuropathies, often preceded by an infection. Antiglycolipid antibody titres are frequently elevated in sera from the acute-phase patients. Particularly, IgG anti-GQ1b antibodies are positive in as high as 90% of FS cases and thus useful for diagnosis. The development of animal models of antiglycolipid antibody-mediated neuropathies proved that some of these antibodies are directly involved in the pathogenetic mechanisms by binding to the regions where the respective target glycolipid is specifically localised. Discovery of the presence of the antibodies that specifically recognise a new conformational epitope formed by two different gangliosides (ganglioside complex) in the acute-phase sera of some patients with GBS suggested the carbohydrate-carbohydrate interaction between glycolipids. This finding indicated the need for further research in basic glycobiological science. Antiglycolipid antibodies, in particular antigangliosides antibodies, are mostly detected in acute motor axonal neuropathy type of GBS and in FS, and less frequently in the acute inflammatory demyelinating polyneuropathy (AIDP) type of GBS or in central nervous system (CNS) diseases. In the future, the search for the putative antibodies in AIDP and those that might be present in CNS diseases should continue. In addition, more efficient standardisation of antiglycolipid antibody detection methods and use as biomarkers in daily clinical practice in neurology is needed.

The role of antibodies to peripheral nerve antigens in pathogenesis and laboratory evaluation of immune-mediated neuropathies

Detection of antiganglioside autoantibodies and their association with clinically defined subtypes implicate an autoimmune mechanism of peripheraland cranial nerve damage in peripheral neuropathies. Increased titer of antibodies that react with human peripheral nerve antigens have been reported in patients with motor neuropathy including Guillain-Barré syndrome,chronic inflammatory demyelinating polyneuropathy, multifocal motor neuropathy and sensory motor neuropathy. This study represents review of the data related to increased titers of anti-glucoconjugate antibodies in different autoimmune neuropathies and their correlation with existence of structural homology between bacterial and glycoconjugated structures, as a basis for understanding the immune pathological response to glycoproteins and glycolipids present in the human peripheral nerve as target antigens in autoimmune neuropathies. Evaluation of presence and increased level of autoantibodies against peripheral nerve antigens could be an important parameter in laboratory evaluation, diagnosis and prognosis of autoimmune neuropathies and contribute in more efficient therapeutic approaches in treatment of these pathological conditions. Keywords: anti-glycoconjugate antibodies, anti-ganglioside antibodies, peripheral nerves, autoimmune neuropathies

Serum IgG anti-GD1a antibody and mEGOS predict outcome in Guillain-Barré syndrome

OBJECTIVE

Approximately 15%-20% of patients with Guillain-Barré syndrome (GBS) are unable to walk independently at 6 months from the onset of neurological symptom. The modified Erasmus GBS outcome score (mEGOS) has been reported as a prognostic tool.Herein we investigated the association between a poor outcome, inability to walk independently at 6 months and presence of antiganglioside antibodies.

METHODS

The clinical and serological data of 177 patients with GBS were retrospectively collected in Japan to assess the associations between a poor outcome and serum IgG antibodies against each ganglioside (GM1, GD1a, GalNAc-GD1a, GQ1b and GT1a). In addition, we investigated whether the combination of mEGOS and serum IgG antibodies against gangliosides is useful in predicting a poor outcome.

RESULTS

The patients with IgG anti-GD1a antibodies more frequently showed poor outcomes than those without these antibodies (9 (36%) of 25 vs 8 (6%) of 127 patients, p<0.001). Particularly, 80% showed a poor outcome when they had both serum IgG anti-GD1a antibody and a high mEGOS of ≥10 on day 7 of admission.

CONCLUSIONS

The combination of serum IgG anti-GD1a antibodies and a high mEGOS could help in making a more accurate prognosis of patients than mEGOS alone, especially for predicting poor outcomes.

Bickerstaff brainstem encephalitis with or without anti-GQ1b antibody

Objective

To clarify the differences in clinical characteristics between anti-GQ1b antibody-positive and antibody-negative Bickerstaff brainstem encephalitis (BBE).

Methods

We compared 73 anti-GQ1b antibody-positive BBE cases with 10 antibody-negative cases. Their clinical information and sera were collected from various hospitals throughout Japan between 2014 and 2017. The anti-GQ1b antibody was examined in each serum sample by ELISA.

Results

We identified the distinctive findings of anti-GQ1b antibody-positive BBE compared with the antibody-negative cases: (1) upper respiratory infection and sensory disturbance were more common, (2) the cell count or protein concentration was lower in the CSF, (3) the abnormal findings on brain MRI were less, and (4) the consciousness disturbance disappeared earlier. Furthermore, IV immunoglobulin (IVIG) was more frequently administered to the anti-GQ1b antibody-positive cases of BBE compared with the antibody-negative cases.

Conclusions

BBE with anti-GQ1b antibody has homogeneous features. IVIG is the treatment used prevalently for BBE with anti-GQ1b antibody in Japan.

Autoimmune Peripheral Neuropathies and Contribution of Antiganglioside/Sulphatide Autoantibody Testing

Peripheral immune-mediated polyneuropathies (IMPN) are a diverse group of rare neurological illnesses characterized by nerve damage. Leading morphological features are mostly nerve fibre demyelination or combination of axonal damage and demyelination. There has been remarkable progress in the clinical and electrophysiological categorization of acute (fulminant, life-threatening) and chronic (progressive/remitting-relapsing) immune-mediated neuropathies recently. Besides electrophysiological and morphological makers, autoantibodies against glycolipids or paranodal/nodal molecules have been recommended as candidate markers for IMPN. The progress in testing for autoantibodies (autoAbs) to glycolipids such as gangliosides and sulfatide may have significant implications on the stratification of patients and their treatment response. Thus, this topic was reviewed in a presentation held during the 1st Panhellenic Congress of Autoimmune Diseases, Rheumatology and Clinical Immunology in Portaria, Pelion, Greece. For acute IMPN, often referred to as Guillain-Barré syndrome and its variants, several serological markers including autoAbs to gangliosides and sulphatide have been employed successfully in clinical routine. However, the evolution of serological diagnosis of chronic variants, such as chronic inflammatory demyelinating polyneuropathy or multifocal motor neuropathy, is less satisfactory. Serological diagnostic markers could, therefore, help in the differential diagnosis due to their assumed pathogenic role. Additionally, stratification of patients to improve their response to treatment may be possible. In general, a majority of patients respond well to causal therapy that includes intravenous immunoglobulins and plasmapheresis. As second line therapy options, biologicals (e.g., rituximab) and immunosuppressant or immunomodulatory drugs may be considered when patients do not respond adequately.

Beatmung bei neuromuskulären Erkrankungen

Neuromuskuläre Erkrankungen betreffen das erste und zweite Motoneuron, die peripheren Nerven, die neuromuskulären Übertragung und die Muskelzelle. Es handelt sich um eine heterogene Gruppe von erblichen, degenerativen und autoimmunen Erkrankungen. Eine korrekte diagnostische Einordnung ist erforderlich, da zentralnervöse, kardiale, endokrine und weitere Begleitsymptome vorliegen können und für einige Erkrankungen bereits medikamentöse Therapien zur Verfügung stehen. Neuromuskuläre Erkrankungen haben eine große Bedeutung in der neuromuskulären Beatmungsmedizin. Die respiratorische Symptomatik resultiert in der Regel aus Paresen der am Atmen, Schlucken oder Husten beteiligten Muskulatur mit konsekutiver ventilatorischer Insuffienz, Dysphagie bis hin zur Speichelaspiration und Sekretretention. Mittels eines strukturierte Sekretmanagements und einer effektive nichtinvasive oder invasive Beatmungstherapie können neuromuskuläre Patienten viele Jahre mit guter Lebensqualität überleben. Themen dieses Kapitels sind ein Überblick über die neuromuskulären Erkrankungen, die Indikationen und Strategien der nichtinvasiven und der invasiven Beatmung und eine ausführliche Darstellung beatmungsmedizinisch besonders relevanter neuromuskulärer Erkrankungen wie der amyotrophe Lateralsklerose, des Guillain-Barré-Syndroms, der Myasthenia gravis und der Critical-Illness-Polyneuropathie/-Myopathie.

Anti-ganglioside antibodies in patients with Zika virus infection-associated Guillain-Barré Syndrome in Brazil

Zika virus infection is associated with the development of Guillain-Barré syndrome (GBS), a neurological autoimmune disorder caused by immune recognition of gangliosides and other components at nerve membranes. Using a high-throughput ELISA, we have analyzed the anti-glycolipid antibody profile, including gangliosides, of plasma samples from patients with Zika infections associated or not with GBS in Salvador, Brazil. We have observed that Zika patients that develop GBS present higher levels of anti-ganglioside antibodies when compared to Zika patients without GBS. We also observed that a broad repertoire of gangliosides was targeted by both IgM and IgG anti-self antibodies in these patients. Since Zika virus infects neurons, which contain membrane gangliosides, antigen presentation of these infected cells may trigger the observed autoimmune anti-ganglioside antibodies suggesting direct infection-induced autoantibodies as a cause leading to GBS development. Collectively, our results establish a link between anti-ganglioside antibodies and Zika-associated GBS in patients.

On the Lipophilic Nature of Autoreactive IgE in Chronic Spontaneous Urticaria

Chronic spontaneous urticaria (CSU) is a skin disease related to autoreactive IgE in at least a subgroup of patients. However, the nature of this autoreactive IgE remains poorly characterized. This investigation had three objectives: first, to quantity CSU autoreactive IgE; second, to recognize the patterns of CSU autoreactive IgE compared with healthy control IgE; and third, to investigate the physiochemical nature of CSU autoreactive IgE.

Methods: IgE autoreactivity was assessed in sera from 7 CSU and 7 healthy individuals. Autoantigen recognition patterns were assessed using principal component analysis (PCA) and heatmap visualization. Lipophilicity was assessed using NanoOrange reagent.

Results: First, although total IgE levels did not differ significantly, the autoreactive proportion of IgE of CSU patients was 62% ± 37%, 1000-fold higher than that of healthy controls 0.03% ± 0.008% (P = 0.0006). Second, CSU autoreactive IgE differed from healthy control IgE by recognizing more and different autoantigens (226 vs. 34; P = 0.01). Third, the median (with 10-90% percentiles) serum level of lipophilic IgE was 39% (38-40%) in 232 CSU patients, 1.4-fold higher than the 28% (26-29%) of 173 healthy controls (P < 0.0001). Furthermore, lipophilicity correlated with autoreactivity (r = 0.8; P < 0.0001), connecting these two observed features.

Conclusion: We believe that these novel observations about CSU autoreactive IgE, particularly the finding that it is more lipophilic than that of IgE from healthy individuals, will lead to the development of new diagnostic tests and therapies for autoreactive IgE-mediated diseases.

Differential binding patterns of anti-sulfatide antibodies to glial membranes

Sulfatide is a major glycosphingolipid in myelin and a target for autoantibodies in autoimmune neuropathies. However neuropathy disease models have not been widely established, in part because currently available monoclonal antibodies to sulfatide may not represent the diversity of anti-sulfatide antibody binding patterns found in neuropathy patients. We sought to address this issue by generating and characterising a panel of new anti-sulfatide monoclonal antibodies. These antibodies have sulfatide reactivity distinct from existing antibodies in assays and in binding to peripheral nerve tissues and can be used to provide insights into the pathophysiological roles of anti-sulfatide antibodies in demyelinating neuropathies.

Immune-mediated neuropathies

Since the discovery of an acute monophasic paralysis, later coined Guillain-Barré syndrome, almost 100 years ago, and the discovery of chronic, steroid-responsive polyneuropathy 50 years ago, the spectrum of immune-mediated polyneuropathies has broadened, with various subtypes continuing to be identified, including chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) and multifocal motor neuropathy (MMN). In general, these disorders are speculated to be caused by autoimmunity to proteins located at the node of Ranvier or components of myelin of peripheral nerves, although disease-associated autoantibodies have not been identified for all disorders. Owing to the numerous subtypes of the immune-mediated neuropathies, making the right diagnosis in daily clinical practice is complicated. Moreover, treating these disorders, particularly their chronic variants, such as CIDP and MMN, poses a challenge. In general, management of these disorders includes immunotherapies, such as corticosteroids, intravenous immunoglobulin or plasma exchange. Improvements in clinical criteria and the emergence of more disease-specific immunotherapies should broaden the therapeutic options for these disabling diseases.

Varied antibody reactivities and clinical relevance in anti-GQ1b antibody-related diseases

Objective

To investigate the relationship between antibody reactivities against glycolipid complexes and clinical features in Miller Fisher syndrome (MFS), Bickerstaff brainstem encephalitis (BBE), and Guillain-Barré syndrome with ophthalmoplegia (GBS-OP).

Methods

Using glycoarray, antibodies against 10 glycolipid antigens (GM1, GM2, GM4, GD1a, GD1b, GQ1b, galactocerebroside, lactosylceramide, GA1, and sulfatide) and 45 glycolipid complexes consisting 2 of the glycolipids were examined in the sera of 63 patients with GBS-OP, 37 patients with MFS, and 27 patients with BBE.

Results

Antibodies to antigens containing GQ1b were identified in 73% of patients with GBS-OP (46/63), 86.5% of patients with MFS (32/37), and 74.1% of patients with BBE (20/27), and GD1b-related antibodies were identified in 49.2% of patients with GBS-OP (31/63), 29.7% of patients with MFS (11/37), and 11.1% of patients with BBE (3/27). Comparing clinical features between patients with GBS-OP with and without both antibodies, the proportion of patients requiring artificial ventilation and presenting moderate or severe muscle weakness was higher in the positive group than in the negative group (p = 0.017 and p = 0.046, respectively).

Conclusions

Antibodies binding to antigens containing GD1b and to those containing GQ1b may be involved in the development of limb weakness and respiratory failure in anti-GQ1b antibody–related diseases.

Diagnostic insights into chronic-inflammatory demyelinating polyneuropathies

Chronic inflammatory demyelinating polyneuropathy (CIDP) is a rare immune-mediated neuropathy with demyelination of nerve fibers as leading morphological feature. The course of disease can be chronic progressive or remitting relapsing. Whereas for acute immune-mediated neuropathies several serological markers have been identified and used successfully in clinical routine, the serological diagnosis of chronic variants such as CIDP has not yet been evolved satisfactory. The typical CIDP and its various atypical variants are characterized by a certain diversity of clinical phenotype and response to treatment. Thus, diagnostic markers could aid in the differential diagnosis of CIDP variants and stratification of patients for a better treatment response. Most patients respond well to a causal therapy including steroids, intravenous immunoglobulins and plasmapheresis. Apart from electrophysiological and morphological markers, several autoantibodies have been reported as candidate markers for CIDP, including antibodies against glycolipids or paranodal/nodal molecules. The present review provides a summary of the progress in autoantibody testing in CIDP and its possible implication on the stratification of the CIDP variants and treatment response.

Co-cultures with stem cell-derived human sensory neurons reveal regulators of peripheral myelination

See Saporta and Shy (doi:10.1093/awx048) for a scientific commentary on this article.Effective bidirectional signalling between axons and Schwann cells is essential for both the development and maintenance of peripheral nerve function. We have established conditions by which human induced pluripotent stem cell-derived sensory neurons can be cultured with rat Schwann cells, and have produced for the first time long-term and stable myelinating co-cultures with human neurons. These cultures contain the specialized domains formed by axonal interaction with myelinating Schwann cells, such as clustered voltage-gated sodium channels at the node of Ranvier and Shaker-type potassium channel (Kv1.2) at the juxtaparanode. Expression of type III neuregulin-1 (TIIINRG1) in induced pluripotent stem cell-derived sensory neurons strongly enhances myelination, while conversely pharmacological blockade of the NRG1-ErbB pathway prevents myelination, providing direct evidence for the ability of this pathway to promote the myelination of human sensory axons. The β-secretase, BACE1 is a protease needed to generate active NRG1 from the full-length form. Due to the fact that it also cleaves amyloid precursor protein, BACE1 is a therapeutic target in Alzheimer's disease, however, consistent with its role in NRG1 processing we find that BACE1 inhibition significantly impairs myelination in our co-culture system. In order to exploit co-cultures to address other clinically relevant problems, they were exposed to anti-disialosyl ganglioside antibodies, including those derived from a patient with a sensory predominant, inflammatory neuropathy with mixed axonal and demyelinating electrophysiology. The co-cultures reveal that both mouse and human disialosyl antibodies target the nodal axolemma, induce acute axonal degeneration in the presence of complement, and impair myelination. The human, neuropathy-associated IgM antibody is also shown to induce complement-independent demyelination. Myelinating co-cultures using human induced pluripotent stem cell-derived sensory neurons thus provide insights into the cellular and molecular specialization of axoglial signalling, how pharmacological agents may promote or impede such signalling and the pathogenic effects of ganglioside antibodies.awx012media15372351982001.

Guillain-Barré syndrome: a century of progress

In 1916, Guillain, Barré and Strohl reported on two cases of acute flaccid paralysis with high cerebrospinal fluid protein levels and normal cell counts - novel findings that identified the disease we now know as Guillain-Barré syndrome (GBS). 100 years on, we have made great progress with the clinical and pathological characterization of GBS. Early clinicopathological and animal studies indicated that GBS was an immune-mediated demyelinating disorder, and that severe GBS could result in secondary axonal injury; the current treatments of plasma exchange and intravenous immunoglobulin, which were developed in the 1980s, are based on this premise. Subsequent work has, however, shown that primary axonal injury can be the underlying disease. The association of Campylobacter jejuni strains has led to confirmation that anti-ganglioside antibodies are pathogenic and that axonal GBS involves an antibody and complement-mediated disruption of nodes of Ranvier, neuromuscular junctions and other neuronal and glial membranes. Now, ongoing clinical trials of the complement inhibitor eculizumab are the first targeted immunotherapy in GBS.

Serological study using glycoarray for detecting antibodies to glycolipids and glycolipid complexes in immune-mediated neuropathies

We performed a serological investigation using glycoarray in Guillain-Barré syndrome (GBS), chronic inflammatory demyelinating polyradiculoneuropathy (CIDP), and multifocal motor neuropathy (MMN). Antibodies to 10 glycolipids and 45 glycolipid complexes were tested. Anti-GM1/sulfatide and anti-GA1/sulfatide IgG antibodies were common in GBS (20.0% and 19.0%, respectively). Anti-GQ1b/sulfatide IgG antibody was detected in 14.0% of GBS patients. IgG antibodies to antigens containing GQ1b were significantly correlated with ophthalmoplegia in GBS (p<0.01). IgM antibodies to antigens containing GM1 or GalNAc-GD1a were in 50% and 37.5% of MMN patients, respectively. Glycoarray is efficient for detecting antibodies against numerous glycolipid complexes in immune-mediated neuropathies.

Guillain-Barré syndrome

Guillain-Barré syndrome is the most common and most severe acute paralytic neuropathy, with about 100,000 people developing the disorder every year worldwide. Under the umbrella term of Guillain-Barré syndrome are several recognisable variants with distinct clinical and pathological features. The severe, generalised manifestation of Guillain-Barré syndrome with respiratory failure affects 20-30% of cases. Treatment with intravenous immunoglobulin or plasma exchange is the optimal management approach, alongside supportive care. Understanding of the infectious triggers and immunological and pathological mechanisms has advanced substantially in the past 10 years, and is guiding clinical trials investigating new treatments. Investigators of large, worldwide, collaborative studies of the spectrum of Guillain-Barré syndrome are accruing data for clinical and biological databases to inform the development of outcome predictors and disease biomarkers. Such studies are transforming the clinical and scientific landscape of acute autoimmune neuropathies.

Seasonal variation in Guillain-Barré syndrome: a systematic review, meta-analysis and Oxfordshire cohort study

INTRODUCTION

Evidence for seasonal variation in incidence and subtype of Guillain-Barré syndrome (GBS) is contradictory, but has implications for provision of neurological services and understanding pathogenesis.

METHODS

We searched PubMed and EMBASE between inception and January 2014, including all studies reporting seasonal incidence of GBS. We included a retrospective cohort study of patients with GBS at the John Radcliffe Hospital, Oxford 2001-2012 and determined the seasonal variation in GBS incidence and length of stay. The incidence rate ratio (IRR) for winter versus summer was pooled across studies by fixed and random effects meta-analysis weighted by inverse variance, stratified by geographical region, infectious prodrome and GBS subtype.

RESULTS

Across 9836 patients from 42 studies there was a 14% increased risk of GBS in winter versus summer (IRR=1.14, 1.02-1.27, p=0.020), with significant heterogeneity between studies (I(2)=77%, p<0.0001), including significant seasonal variation in Oxford (n=140; p=0.037) for winter versus summer (IRR=1.92, 1.18-3.11, p=0.004) but a non-significantly reduced length of stay for winter versus other seasons (15 vs 21 days, p=0.08). Across all studies, there was greater seasonal variation with respiratory prodrome (IRR=3.06, 1.84-5.11, p<0.0001) than diarrhoeal prodrome (IRR=1.10, 0.60-2.00, p=0.76) and a greater incidence in winter in Western countries (IRR=1.28), the Far East (IRR=1.20) and Middle East (IRR=1.12), with a lower incidence in the Indian subcontinent (IRR=0.86) and Latin America (IRR=0.75).

DISCUSSION

Incidence of GBS was greater in winter than summer, but this was not evident in all geographical regions. This is likely to be related to regional variation in prodromal illnesses.

Progress in inflammatory neuropathy -the legacy of Dr Jack Griffin

The past quarter of a century has brought incredible advances in our understanding of inflammatory neuropathies, and the insights into Guillain-Barré syndrome (GBS) began in the 1990s with the seminal work of Dr Jack Griffin and his colleagues. In this essay, we provide a tribute to Jack, and review the recent progress in a field that he termed his personal favourite. In particular, we discuss the new developments in our understanding and diagnosis of inflammatory neuropathies, the recent emergence of the node of Ranvier and the paranode as sites of intensive investigation, and the mechanistic evidence that is providing a platform for therapeutic development studies.

Biomarkers of Guillain-Barré Syndrome: Some Recent Progress, More Still to Be Explored

Guillain-Barré syndrome (GBS), the axonal subtype of which is mainly triggered by C. jejuni with ganglioside-mimicking lipooligosaccharides (LOS), is an immune-mediated disorder in the peripheral nervous system (PNS) accompanied by the disruption of the blood-nerve barrier (BNB) and the blood-cerebrospinal fluid barrier (B-CSF-B). Biomarkers of GBS have been extensively explored and some of them are proved to assist in the clinical diagnosis and in monitoring disease progression as well as in assessing the efficacy of immunotherapy. Herein, we systemically review the literature on biomarkers of GBS, including infection-/immune-/BNB, B-CSF-B, and PNS damage-associated biomarkers, aiming at providing an overview of GBS biomarkers and guiding further investigations. Furthermore, we point out further directions for studies on GBS biomarkers.

Chronic inflammatory demyelinating polyradiculoneuropathy: from pathology to phenotype

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is an inflammatory neuropathy, classically characterised by a slowly progressive onset and symmetrical, sensorimotor involvement. However, there are many phenotypic variants, suggesting that CIDP may not be a discrete disease entity but rather a spectrum of related conditions. While the abiding theory of CIDP pathogenesis is that cell-mediated and humoral mechanisms act together in an aberrant immune response to cause damage to peripheral nerves, the relative contributions of T cell and autoantibody responses remain largely undefined. In animal models of spontaneous inflammatory neuropathy, T cell responses to defined myelin antigens are responsible. In other human inflammatory neuropathies, there is evidence of antibody responses to Schwann cell, compact myelin or nodal antigens. In this review, the roles of the cellular and humoral immune systems in the pathogenesis of CIDP will be discussed. In time, it is anticipated that delineation of clinical phenotypes and the underlying disease mechanisms might help guide diagnostic and individualised treatment strategies for CIDP.

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

BACKGROUND AND PURPOSE

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'.

METHODS

Immunoglobulin G antibodies to ganglioside complex (GSC) of GQ1b or GT1a with GM1, GD1a, GD1b or GT1b were tested in sera from patients with anti-GQ1b (n = 708) or anti-GT1a (n = 696) IgG antibodies. Optical densities of the single anti-GQ1b or anti-GT1a antibodies were used as reference (100%), and those of anti-GSC antibodies were expressed in percentages to reference. The relationships between anti-GSC antibody reactivity and the corresponding clinical features were assessed by multivariate logistic regression analysis.

RESULTS

Ophthalmoplegia and hypersomnolence were significantly associated with complex-attenuated anti-GQ1b and anti-GT1a antibodies. Ataxia was associated with GD1b- and GT1b-enhanced anti-GQ1b antibodies or GM1-enhanced anti-GT1a antibodies. Bulbar palsy was associated with GT1b-enhanced anti-GQ1b antibodies. Neck weakness was associated with GD1a-enhanced anti-GQ1b antibodies. Arm weakness was associated with GD1b-enhanced anti-GQ1b and GD1a-enhanced anti-GT1a antibodies. Leg weakness was associated with GD1a-enhanced anti-GQ1b and anti-GT1a antibodies.

CONCLUSIONS

Differences in fine specificity of anti-GQ1b antibodies are associated with clinical features, possibly due to the different expression of gangliosides in different parts of the nervous system.

Diagnostic Utility of Auto Antibodies in Inflammatory Nerve Disorders

A wide range of autoantibodies have been described in immune-mediated nerve disorders that target glycans borne by glycolipids and glycoproteins enriched in the peripheral nerves. Their use as diagnostic biomarkers is very widespread, despite some limitations on sensitivity and specificity, and the lack of standardized assays and access to quality assurance schemes. Although many methods have been applied to measurement, ELISA, in the form of commercial kits or in-house assays, still remains the most widely available and convenient assay methodology.Some antibodies have a particularly robust and widely appreciated clinical significance. Thus, the anti-MAG IgM antibodies that are found in IgM paraprotein related neuropathies define a relatively uniform clinical and prognostic phenotype. IgG antibodies against gangliosides GM1 and GD1a are strongly associated with motor axonal variants of Guillain-Barré syndrome, and anti-GQ1b with Miller Fisher syndrome. In other chronic neuropathies, antibodies against disialylated gangliosides including GD1b and GD3 are detected in ataxic neuropathies, usually associated with an IgM paraprotein, and antibodies against GM1 and the complex GM1:GalC are frequently found in multifocal motor neuropathy. Unfortunately, autoantibodies strongly associated with the diagnosis of chronic inflammatory demyelinating polyneuropathies and with demyelinating forms of GBS are still lacking.Identification of autoantibodies that map onto a specific clinical phenotype not only allows for improved classification, but also provides better understanding of the pathophysiology of inflammatory neuropathies and the potential for therapeutic interventions.