Immunotherapy of Guillain-Barré syndrome

Animal models of immune-mediated demyelinating polyneuropathies

Immune-mediated demyelinating polyneuropathies (IMDPs) are rare disorders in which dysregulated adaptive immune responses cause peripheral nerve demyelinating inflammation and axonal injury in susceptible individuals. Despite significant advances in understanding IMDP pathogenesis guided by patient data and representative mammalian models, specific therapies are lacking. Significant knowledge gaps in IMDP pathogenesis still exist, e.g. precise antigen(s) and mechanisms that initially trigger immune system activation and identification of large population disease susceptibility factors. The initial directional cues for antigen-specific effector or autoreactive leukocyte trafficking into peripheral nerves are also unknown. An overview of current animal models, with emphasis on the experimental autoimmune neuritis and spontaneous autoimmune peripheral polyneuropathy models, is provided. Insights on the initial directional cues for peripheral nerve tissue specific autoimmunity using a novel Major Histocompatibility Complex class II conditional knockout mouse strain are also discussed, suggesting an essential research tool to study cell- and time-dependent adaptive immunity in autoimmune diseases.

Causal role of the pyrimidine deoxyribonucleoside degradation superpathway mediation in Guillain-Barré Syndrome via the HVEM on CD4 + and CD8 + T cells

Immune system regulation is a key indicator of the gut microbiota (GM) influencing disease development. The causal role of the GM in Guillain-Barré syndrome (GBS) and whether it can be mediated by immune cells is unknown. Genome-wide association study (GWAS) summary statistics for the GM were obtained from the Dutch Microbiota Project (n = 7,738) and the FINRISK 2002 (FR02) cohort (n = 5,959). Inverse variance weighting method (IVW) were used as the main method to evaluate the causal relationship between GM and GBS. Subsequently, the mediating effects of 731 immune traits were evaluated. Additionally, we also executed the Bayesian Weighting algorithm for verification. Mendelian randomization (MR) analysis determined the protective effect of the pyrimidine deoxyribonucleoside degradation superpathway on GBS (IVW: P = 0.0019, OR = 0.4508). It is worth noting that in the causal effects of pyrimidine deoxyribonucleoside degradation superpathway on GBS, the mediated proportions of herpesvirus entry mediator (HVEM) ( HVEM on CM CD4 + , HVEM on naive CD4 + , HVEM on CD45RA - CD4 + , HVEM on CM CD8br) in the T cell maturation stage on GBS were -0.0398, -0.0452, -0.0414, -0.0425, accounting for 5.00%, 5.67%, 5.19% and 5.34% of the total effect. 11 types of intestinal bacteria might be involved in the pyrimidine deoxyriboside degradation superpathway, including Staphylococcus A fleurettii, AR31,CAG-274 sp000432155, Photobacterium, Acetobacteraceae, Dysgonomonadaceae, NK4A144,Leptospirae, CAG-81 sp000435795, Leptospirales and CAG-873 sp001701165. This study suggests that there is a causal relationship between pyrimidine deoxyribonucleoside degradation superpathway and GBS, which may be mediated by HVEM on CD4 + and CD8 + T cells. As a bidirectional molecular switch, HVEM plays an important role in T cell regulation. 11 intestinal flora were found to be involved in pyrimidine deoxyribonucleoside degradation superpathway, and their changes may be related to the occurrence of GBS. However, extensive research is still warranted before microbiome sequencing can be used for prevention and targeted treatment of GBS.

Rapid Improvement in Guillain-Barré Syndrome With Demyelinating and Secondary Axonal Involvement: A Case Report

Guillain-Barré syndrome (GBS) is a major cause of acute neuropathy worldwide. The accurate classification of GBS subtypes is essential for diagnosis and prognosis, with acute inflammatory demyelinating polyneuropathy generally linked to more favorable outcomes. This case report examines a 65-year-old Sudanese man who experienced a six-day progression of symmetrical lower limb weakness and numbness, which rapidly escalated to significant motor impairment. Clinical evaluations and diagnostic tests identified primary demyelinating polyradiculoneuropathy with secondary axonal damage. Despite severe initial weakness and hypoxia, the patient showed significant recovery. Follow-up assessments confirmed full motor recovery and independent mobility. This case report aims to fill the gap in local data and provide valuable insights into the clinical features and outcomes of GBS in the Saudi Arabian context.

Neuron-Schwann cell interactions in peripheral nervous system homeostasis, disease, and preclinical treatment

Schwann cells (SCs) have a critical role in the peripheral nervous system. These cells are able to support axons during homeostasis and after injury. However, mutations in genes associated with the SCs repair program or myelination result in dysfunctional SCs. Several neuropathies such as Charcot-Marie-Tooth (CMT) disease, diabetic neuropathy and Guillain-Barré syndrome show abnormal SC functions and an impaired regeneration process. Thus, understanding SCs-axon interaction and the nerve environment in the context of homeostasis as well as post-injury and disease onset is necessary. Several neurotrophic factors, cytokines, and regulators of signaling pathways associated with proliferation, survival and regeneration are involved in this process. Preclinical studies have focused on the discovery of therapeutic targets for peripheral neuropathies and injuries. To study the effect of new therapeutic targets, modeling neuropathies and peripheral nerve injuries (PNIs) in vitro and in vivo are useful tools. Furthermore, several in vitro protocols have been designed using SCs and neuron cell lines to evaluate these targets in the regeneration process. SCs lines have been used to generate effective myelinating SCs without success. Alternative options have been investigated using direct conversion from somatic cells to SCs or SCs derived from pluripotent stem cells to generate functional SCs. This review will go over the advantages of these systems and the problems associated with them. In addition, there have been challenges in establishing adequate and reproducible protocols in vitro to recapitulate repair SC-neuron interactions observed in vivo. So, we also discuss the mechanisms of repair SCs-axon interactions in the context of peripheral neuropathies and nerve injury (PNI) in vitro and in vivo. Finally, we summarize current preclinical studies evaluating transgenes, drug, and novel compounds with translational potential into clinical studies.

Regulatory Mechanism of M1/M2 Macrophage Polarization in the Development of Autoimmune Diseases

Macrophages are innate immune cells in the organism and can be found in almost tissues and organs. They are highly plastic and heterogeneous cells and can participate in the immune response, thereby playing a crucial role in maintaining the immune homeostasis of the body. It is well known that undifferentiated macrophages can polarize into classically activated macrophages (M1 macrophages) and alternatively activated macrophages (M2 macrophages) under different microenvironmental conditions. The directions of macrophage polarization can be regulated by a series of factors, including interferon, lipopolysaccharide, interleukin, and noncoding RNAs. To elucidate the role of macrophages in various autoimmune diseases, we searched the literature on macrophages with the PubMed database. Search terms are as follows: macrophages, polarization, signaling pathways, noncoding RNA, inflammation, autoimmune diseases, systemic lupus erythematosus, rheumatoid arthritis, lupus nephritis, Sjogren's syndrome, Guillain-Barré syndrome, and multiple sclerosis. In the present study, we summarize the role of macrophage polarization in common autoimmune diseases. In addition, we also summarize the features and recent advances with a particular focus on the immunotherapeutic potential of macrophage polarization in autoimmune diseases and the potentially effective therapeutic targets.

Guillain-Barré Syndrome in Adults in a Decade: The Largest, Single-Center, Cross-Sectional Study From the Kingdom of Saudi Arabia

BACKGROUND

Guillain-Barré Syndrome (GBS) is the most common cause of acute, usually post-infectious, peripheral neuropathy resulting in a symmetrical, ascending paralysis. We evaluated the clinical and neurophysiological features, treatment, and outcomes of patients with GBS in our center.

METHODS

A retrospective chart review on patients with GBS admitted to King Abdulaziz Medical City, Riyadh, Saudi Arabia, from January 2011 to December 2020. Data were analyzed using JMP statistical software version 15 pro.

RESULTS

A total of 86 patients who met the criteria were included, 55 (64%) were males, with a mean age of 49.5+/-17.5 years. Antecedent infection was reported in 53 (61.6%), 51 (62.2%) presented within one week of symptoms onset. Ascending weakness was seen in 55 (70.5%), while 70 (81.4%) had areflexia. Acute motor axonal neuropathy (AMAN) was the commonest electrophysiological type of GBS in 41 (51.9%) patients. Albuminocytologic dissociation was seen in 48 (57%) who had lumbar puncture. Nearly half, 41 (47.7%) were admitted to the intensive care unit (ICU). Seventy (81.3%) were treated with intravenous immunoglobulin. There was no significant difference in the clinical presentation, management, ICU requirement, and discharge disposition between males and females. Females were more likely to have a higher disability at discharge (p=0.01). Patients younger than 60 years were more likely to require ICU admission (p=<0.01).

CONCLUSION

Our patients with GBS were slightly older than previously reported from the region. AMAN was the commonest type of GBS. Younger patients were more likely to need ICU admission, whereas females were more likely to have a more severe disability.

Plasma exchange (PE) versus intravenous immunoglobulin (IVIG) for the treatment of Guillain-Barré syndrome (GBS) in patients with severe symptoms: A systematic review and meta-analysis

Background and purpose

Guillain- Barré syndrome (GBS) is a neuropathic condition that leads to the rapid development of impairments and is characterized by weakness and numbness or tingling sensation in the legs and arms and sometimes loss of movement and feeling in the legs, arms, upper body, and face. Currently, the cure for the disease is yet to be developed. However, treatment options such as intravenous immunoglobulin (IVIG) and plasma exchange (PE) have been used to minimize the symptoms and duration of the disease. Therefore, this systematic review and meta-analysis compared the efficacy of IVIG and PE in treating GBS patients with severe symptoms.

Methodology

Six electronic databases, including PubMed, Embase, Scopus, ScienceDirect, Medline, and Google scholar, were scoured for articles related and relevant to our research. Additionally, more studies were obtained through the reference lists of the studies retrieved from these electronic databases. Quality assessment and statistical data analysis were conducted using Review Manager software (RevMan 5.4.1).

Results

The search for relevant articles resulted in 3253 articles, of which only 20 were included for review in the current study. A sub-group analysis indicated no significant difference in the curative effect (Hughes score reduces by at least one score 4 weeks after GBS treatment; OR: 1.00; 95% CI: 0.66-1.52; p = 1.00 and Achieving grade 0 or 1 on Hughes scale; OR: 1.03; 95% CI: 0.27-3.94; p = 0.97). Similarly, the statistical showed that the difference in length of hospitalization and duration of mechanical ventilation was insignificant between the IVIG and PE group (Standard Mean Difference (SMD): -0.45; 95% CI: -0.92, 0.02; I2 = 91%; p = 0.06 and SMD: -0.54; 95% CI: -1.67, 0.59; I2 = 93%; p = 0.35, respectively). Moreover, the meta-analysis did not find any significant difference in the risk of GBS relapse (RR: 0.47; 95% CI: 0.20-1.14; p = 0.10) and risk of complications related to the treatment regimens (RR: 1.03; 95% CI: 0.71-1.48; p = 0.89). However, the statistical analysis of outcomes from 3 studies showed that the risk of discontinuation was significantly lower in the IVIG group than in the PE group (RR: 0.22; 95% CI: 0.06-0.88; p = 0.03).

Conclusion

Our study suggests that IVIG and PE have similar curative effects. Similarly, IVIG seems easier to use and thus can be preferred for treating GBS.

A diagnostic support system based on pain drawings: binary and k-disease classification of EDS, GBS, FSHD, PROMM, and a control group with Pain2D

BACKGROUND AND OBJECTIVE

The diagnosis of rare diseases (RDs) is often challenging due to their rarity, variability and the high number of individual RDs, resulting in a delay in diagnosis with adverse effects for patients and healthcare systems. The development of computer assisted diagnostic decision support systems could help to improve these problems by supporting differential diagnosis and by prompting physicians to initiate the right diagnostic tests. Towards this end, we developed, trained and tested a machine learning model implemented as part of the software called Pain2D to classify four rare diseases (EDS, GBS, FSHD and PROMM), as well as a control group of unspecific chronic pain, from pen-and-paper pain drawings filled in by patients.

METHODS

Pain drawings (PDs) were collected from patients suffering from one of the four RDs, or from unspecific chronic pain. The latter PDs were used as an outgroup in order to test how Pain2D handles more common pain causes. A total of 262 (59 EDS, 29 GBS, 35 FSHD, 89 PROMM, 50 unspecific chronic pain) PDs were collected and used to generate disease specific pain profiles. PDs were then classified by Pain2D in a leave-one-out-cross-validation approach.

RESULTS

Pain2D was able to classify the four rare diseases with an accuracy of 61-77% with its binary classifier. EDS, GBS and FSHD were classified correctly by the Pain2D k-disease classifier with sensitivities between 63 and 86% and specificities between 81 and 89%. For PROMM, the k-disease classifier achieved a sensitivity of 51% and specificity of 90%.

CONCLUSIONS

Pain2D is a scalable, open-source tool that could potentially be trained for all diseases presenting with pain.

Case Report: Chlamydia psittaci pneumonia complicated by Guillain-Barré syndrome detected using metagenomic next-generation sequencing

Psittacosis and Guillain-Barré syndrome are both rare clinical diseases with low incidence, and their combination has rarely been reported. Here, we report a case of Chlamydia psittaci pneumonia combined with Guillain-Barré syndrome. The patient initially presented with high fever, difficulty breathing, and fatigue. Chest computerised tomography indicated large consolidation opacities in both lungs. Metagenomic next-generation sequencing clearly identified the pathogen as C. psittaci. The patient's fever subsided after targeted antibiotic treatment, but difficulty breathing and fatigue worsened, and the patient developed symmetric limb numbness and weakness. Lumbar puncture, electrophysiological examination, and clinical characteristics were suggestive of Guillain-Barré syndrome, and the symptoms improved after treatment with human immunoglobulin. The results of this study suggest that metagenomic next-generation sequencing is useful for the rapid diagnosis of pulmonary infectious agents. Psittacosis is closely associated with the development of Guillain-Barré syndrome; however, more cases are needed to support this conclusion, and early targeted antibiotic treatment, immunotherapy, and basic supportive treatment are essential for improving outcomes.

Diagnostic Pitfalls in Guillain-Barré Syndrome: Case Report and Literature Review

Guillain-Barré syndrome (GBS) represents a group of acute immune-mediated polyradiculoneuropathies that is usually characterized by symmetrical limb weakness and areflexia. GBS can also lead to atypical clinical findings, which may lead to confusion and errors in the diagnosis. In this report, we describe a case of Guillain-Barré syndrome in a 7-year-old child who presented with neck stiffness, headache and vomiting mimicking acute meningoencephalitis, arthritis and myositis. Symptoms of ascending paralysis developed subsequently. Clearly, the atypical presentation of GBS is a significant dilemma for pediatricians and may lead to delays in diagnosis and treatment.

Campylobacter jejuni and Postinfectious Autoimmune Diseases: A Proof of Concept in Glycobiology

Glycans, one of the most diverse groups of macromolecules, are ubiquitous constituents of all cells and have many critical functions, including the interaction between microbes and their hosts. One of the best model organisms to study the host-pathogen interaction, the gastrointestinal pathogen Campylobacter jejuni dedicates extensive resources to glycosylation and exhibits a diverse array of surface sugar-coated displays. The first bacterium where N-linked glycosylation was described, C. jejuni can additionally modify proteins by O-linked glycosylation, has extracellular capsular polysaccharides that are important for virulence and represent the major determinant of the Penner serotyping scheme, and has outer membrane lipooligosaccharides that participate in processes such as colonization, survival, inflammation, and immune evasion. In addition to causing gastrointestinal disease and extraintestinal infections, C. jejuni was also linked to postinfectious autoimmune neuropathies, of which Guillain-Barré syndrome (GBS) and Miller Fisher syndrome (MFS) are the most extensively characterized ones. These postinfectious autoimmune neuropathies occur when specific bacterial surface lipooligosaccharides mimic gangliosides in the host nervous system. C. jejuni provided the first proof of concept for the involvement of molecular mimicry in the pathogenesis of an autoimmune disease and, also, for the ability of a bacterial polymorphism to shape the clinical presentation of the postinfectious autoimmune neuropathy. The scientific journey that culminated with elucidating the mechanistic details of the C. jejuni-GBS link was the result of contributions from several fields, including microbiology, structural biology, glycobiology, genetics, and immunology and provides an inspiring and important example to interrogate other instances of molecular mimicry and their involvement in autoimmune disease.

Intravenous immunoglobulin prevents peripheral liver transduction of intrathecally delivered AAV vectors

Gene therapy using neurotropic adeno-associated virus vectors represents an emerging solution for genetic disorders affecting the central nervous system. The first approved central nervous system-targeting adeno-associated virus gene therapy, Zolgensma®, for treating spinal muscular atrophy is administered intravenously at high doses that cause liver-associated adverse events in 20%–30% of patients. Intrathecal routes of vector administration, such as the intra-cisterna magna route, provide efficient gene transduction to central nervous system cells while reducing off-target liver transduction. However, significant levels of liver transduction often occur upon intra-cisterna magna vector delivery in preclinical studies. Using vectors expressing monoclonal antibody transgenes, we examined whether passive transfer of adeno-associated virus-neutralizing antibodies as intravenous immunoglobulin before intrathecal adeno-associated virus delivery improved the safety of viral gene therapy targeting the central nervous system in mice and nonhuman primates. We used intracerebroventricular and intra-cisterna magna routes for vector administration to mice and nonhuman primates, respectively, and evaluated transgene expression and vector genome distribution. Our data indicate that pretreatment with intravenous immunoglobulin significantly reduced gene transduction to the liver and other peripheral organs but not to the central nervous system in both species. With further refinement, this method may improve the safety of adeno-associated virus-based, central nervous system-targeting gene therapies in clinical settings.

Clinical efficacy of high-dose intravenous gammaglobulin in acute Guillain-Barre syndrome and effect on serum concentration of inflammatory factors

OBJECTIVE

To explore the clinical efficacy of high-dose intravenous gammaglobulin (IVIG) in acute Guillain-Barre syndrome (GBS) and its effect on serum concentrations of inflammatory factors.

METHODS

A total of 111 patients with acute GBS were enrolled in this retrospective study. They were admitted to Ji'nan City People's Hospital from January 2019 to December 2020. According to the treatment method, the patients were divided into a control group (n=53, received routine treatment) and an observation group (n=58, received high-dose IVIG in addition to routine treatment). The clinical efficacy, Barthel index for activities of daily living (ADL), serum concentrations of inflammatory factors (IL-6, TNF-α, NO) in peripheral blood, potential of electromyography signals, abnormal rates of motor and sensory conduction velocity, and F wave abnormality rate were compared. Also, the risk factors affecting IVIG treatment efficacy were analyzed.

RESULTS

The overall response rate, and Barthel index for ADL were higher, while serum concentrations of IL-6, TNF-α, and NO were lower in the observation group than the control group (all P<0.05). There were differences in spontaneous potential and motor potential before and after treatment in both groups (both P<0.05). The observation group showed lower abnormal rates of motor and sensory conduction velocity, F wave abnormality rate, and prolonged latency rate than the control group (all P<0.05). Concomitant lung infection, respiratory muscle involvement, and treatment with high-dose IVIG >2 weeks from onset were independent risk factors for treatment efficacy.

CONCLUSION

High-dose IVIG has good clinical efficacy in treating acute GBS by reducing the serum concentrations of IL-6, TNF-α, and NO, improving patients' abnormal muscle electrical condition, and promoting recovery. It is recommended for use clinically at an early stage. At the same time, lung infection must be prevented.

Analysis of Clinical Symptoms of Guillain–Barré Syndrome Induced by Heat Stroke: Three Case Reports and Literature Review

Background

Heat stroke is a potentially fatal condition that is caused by elevated core temperature. Guillain–Barré syndrome (GBS) induced by heat stroke is extremely rare and has only been reported in few case reports. The purpose of this case study was to evaluate the clinical symptoms, neuroelectrophysiological and imageological features of GBS after heat stroke.

Methods

We reviewed our hospital records and previously published reports to find the cases of GBS after heat stroke. The clinical, imageological, and electrophysiological profiles, treatment and prognosis were presented and analyzed.

Results

We retrieved three cases of GBS induced by heat stroke from our hospital, which presented as lesions on multiple cranial and peripheral nerves and albuminocytologic dissociation in the cerebrospinal fluid. All of these patients had disorders of consciousness at the early stage of heat stroke and a “pseudo-recovery period” after they recovered from coma after heat stroke. After immunoglobulin administration and immunoregulation therapy, these patients' neurological deficiencies were relieved significantly. But there are still disabilities and almost totally reliant on others.

Conclusions

The number of the cases of GBS induced by HS reported in this study has been the most in the recent 5 years. Clinicians should pay attention to patients with heat stroke with sustained coma and the sudden quadriplegia. Early, exact and timely diagnosis and treatment of GBS need to be performed, to accelerate recovery and improve prognosis.

IgG4 Autoantibodies in Organ-Specific Autoimmunopathies: Reviewing Class Switching, Antibody-Producing Cells, and Specific Immunotherapies

Organ-specific autoimmunity is often characterized by autoantibodies targeting proteins expressed in the affected tissue. A subgroup of autoimmunopathies has recently emerged that is characterized by predominant autoantibodies of the IgG4 subclass (IgG4-autoimmune diseases; IgG4-AID). This group includes pemphigus vulgaris, thrombotic thrombocytopenic purpura, subtypes of autoimmune encephalitis, inflammatory neuropathies, myasthenia gravis and membranous nephropathy. Although the associated autoantibodies target specific antigens in different organs and thus cause diverse syndromes and diseases, they share surprising similarities in genetic predisposition, disease mechanisms, clinical course and response to therapies. IgG4-AID appear to be distinct from another group of rare immune diseases associated with IgG4, which are the IgG4-related diseases (IgG4-RLD), such as IgG4-related which have distinct clinical and serological properties and are not characterized by antigen-specific IgG4. Importantly, IgG4-AID differ significantly from diseases associated with IgG1 autoantibodies targeting the same organ. This may be due to the unique functional characteristics of IgG4 autoantibodies (e.g. anti-inflammatory and functionally monovalent) that affect how the antibodies cause disease, and the differential response to immunotherapies of the IgG4 producing B cells/plasmablasts. These clinical and pathophysiological clues give important insight in the immunopathogenesis of IgG4-AID. Understanding IgG4 immunobiology is a key step towards the development of novel, IgG4 specific treatments. In this review we therefore summarize current knowledge on IgG4 regulation, the relevance of class switching in the context of health and disease, describe the cellular mechanisms involved in IgG4 production and provide an overview of treatment responses in IgG4-AID.

Case Report: Guillain-Barré Syndrome as Primary Presentation of Systemic Lupus Erythematosus (SLE-GBS) in a Teenage Girl

Peripheral nervous system involvement accounts for fewer than 10% of SLE cases with neuropsychiatric manifestations. Guillain-Barré syndrome (GBS) as the presenting, major manifestation of pediatric SLE is extremely rare, and the best treatment approach is unknown. A 14-year-old, previously healthy female teenager developed classic features of GBS with ascending bilateral muscle weakness leading to respiratory insufficiency, associated with protein-cell dissociation in cerebro-spinal fluid, nerve root enhancement by MRI and reduction in compound muscle action potential amplitude. SLE was diagnosed serologically and histologically (lupus nephritis WHO class II). Despite immediate treatment with intravenous immunoglobulin (IVIg), methylprednisolone pulses and subsequently, rituximab, the patient required prolonged mechanical ventilation. She achieved full recovery following 14 PLEX treatments and two more rituximab infusions. Anti-dsDNA, C3, C4 and urinalysis normalized while anti-Smith and Sjögren antibodies persisted 15 months after disease onset, with no other lupus manifestations. Review of the literature revealed two pediatric cases of GBS at the onset of SLE and a third case with GBS 6 years after the diagnosis of SLE. Conventional GBS therapy may not be adequate to treat SLE-GBS. SLE should be included in the differential diagnosis of GBS. Importantly, treatment experiences and outcomes of such cases need be reported to inform future treatment recommendations.

Severe Acute Motor Axonal Neuropathy associated with Influenza-A (H1N1) Infection and Prolonged Respiratory Failure - A Case Report

Acute Motor Axonal Neuropathy (AMAN) is an immune-mediated disorder of the peripheral nervous system, part of the spectrum of the Guillain-Barre syndrome (GBS). An infectious event most often triggers it reported a few weeks before the onset. The reported case is of a 56 years-old woman who developed acute motor axonal neuropathy three weeks after respiratory infection with influenza A virus subtype H1N1. Despite early treatment with plasmapheresis and intravenous immunoglobulins, the patient remained tetraplegic, mechanically ventilated for five months, with repetitive unsuccessful weaning trails. The probable cause was considered to be phrenic nerve palsy in the context of acute motor axonal neuropathy. This case highlights that acute motor axonal neuropathy is a severe and life-threatening form of Guillain-Barre syndrome associated with significant mortality and morbidity. Neurological and physical recovery strongly depend on the inter-professional effort in an intensive care unit and neurology professionals.

Novel Immunological and Therapeutic Insights in Guillain-Barré Syndrome and CIDP

Inflammatory neuropathies are a heterogeneous group of rare diseases of the peripheral nervous system that include acute and chronic diseases, such as Guillain-Barré syndrome (GBS) and chronic inflammatory demyelinating polyradiculoneuropathy (CIDP). The etiology and pathophysiological mechanisms of inflammatory neuropathies are only partly known, but are considered autoimmune disorders in which an aberrant immune response, including cellular and humoral components, is directed towards components of the peripheral nerve causing demyelination and axonal damage. Therapy of these disorders includes broad-spectrum immunomodulatory and immunosuppressive treatments, such as intravenous immunoglobulin, corticosteroids, or plasma exchange. However, a significant proportion of patients do not respond to any of these therapies, and treatment selection is not optimized according to disease pathophysiology. Therefore, research on disease pathophysiology aiming to reveal clinically and functionally relevant disease mechanisms and the development of new treatment approaches are needed to optimize disease outcomes in CIDP and GBS. This topical review describes immunological progress that may help guide therapeutic strategies in the future in these two disorders.

Case Report: Early-Onset Guillain-Barre Syndrome Mimicking Stroke

Introduction: Guillain-Barre syndrome (GBS) is an acute immune-mediated inflammatory demyelinating polyneuropathy characterized by symmetrical limb weakness and areflexia. GBS can have different clinical manifestations; hence, the initial symptoms are also varied. Here, we describe a rare case of GBS presenting as hemiparesis and cranial nerve palsy, which mimic brainstem stroke. Case Presentation: A 53-year-old man was admitted to the hospital with a 3-h history of left-arm weakness, glossolalia, and right eyelid droop. After admission, his condition suddenly worsened, with quadriplegia, bilateral peripheral facial palsy, bilateral ophthalmoplegia, and other neurological symptoms. Based on the findings from a neurological examination, MRI, cerebrospinal fluid analysis, and nerve conduction study, a diagnosis of GBS was made. He received intravenous immunoglobulin (0.4 kg/day) for 5 days. After 20 days of systematic therapy, his dysphagia, dyspnea, facial paralysis, ocular movement disorder, and leg weakness recovered almost completely, but his arms were still moderately impaired, with a power of 4/5. Fortunately, the patient recovered well without any sequelae after 2 years of follow-up. Conclusions: In patients with an atypical presentation, the diagnosis of GBS is often delayed. With this case report, we intend to highlight the fact that some symptoms mimicking stroke may be a feature of GBS at onset; close observation and timely diagnosis are crucial for clinicians. Neuroimaging is a valuable diagnostic tool in differentiating stroke from GBS.

Macrophage roles in peripheral nervous system injury and pathology: Allies in neuromuscular junction recovery

Peripheral nerve injuries remain challenging to treat despite extensive research on reparative processes at the injury site. Recent studies have emphasized the importance of immune cells, particularly macrophages, in recovery from nerve injury. Macrophage plasticity enables numerous functions at the injury site. At early time points, macrophages perform inflammatory functions, but at later time points, they adopt pro-regenerative phenotypes to support nerve regeneration. Research has largely been limited, however, to the injury site. The neuromuscular junction (NMJ), the synapse between the nerve terminal and end target muscle, has received comparatively less attention, despite the importance of NMJ reinnervation for motor recovery. Macrophages are present at the NMJ following nerve injury. Moreover, in denervating diseases, such as amyotrophic lateral sclerosis (ALS), macrophages may also play beneficial roles at the NMJ. Evidence of positive macrophages roles at the injury site after peripheral nerve injury and at the NMJ in denervating pathologies suggest that macrophages may promote NMJ reinnervation. In this review, we discuss the intersection of nerve injury and immunity, with a focus on macrophages.

Pain drawings as a diagnostic tool for the differentiation between two pain-associated rare diseases (Ehlers-Danlos-Syndrome, Guillain-Barré-Syndrome)

Background

The diagnosis of rare diseases poses a particular challenge to clinicians. This study analyzes whether patients’ pain drawings (PDs) help in the differentiation of two pain-associated rare diseases, Ehlers-Danlos Syndrome (EDS) and Guillain-Barré Syndrome (GBS).

Method

The study was designed as a prospective, observational, single-center study. The sample comprised 60 patients with EDS (3 male, 52 female, 5 without gender information; 39.2 ± 11.4 years) and 32 patients with GBS (10 male, 20 female, 2 without gender information; 50.5 ± 13.7 years). Patients marked areas afflicted by pain on a sketch of a human body with anterior, posterior, and lateral views. PDs were electronically scanned and processed. Each PD was classified based on the Ružička similarity to the EDS and the GBS averaged image (pain profile) in a leave-one-out cross validation approach. A receiver operating characteristic (ROC) curve was plotted.

Results

60–80% of EDS patients marked the vertebral column with the neck and the tailbone and the knee joints as pain areas, 40–50% the shoulder-region, the elbows and the thumb saddle joint. 60–70% of GBS patients marked the dorsal and plantar side of the feet as pain areas, 40–50% the palmar side of the fingertips, the dorsal side of the left palm and the tailbone. 86% of the EDS patients and 96% of the GBS patients were correctly identified by computing the Ružička similarity. The ROC curve yielded an excellent area under the curve value of 0.95.

Conclusion

PDs are a useful and economic tool to differentiate between GBS and EDS. Further studies should investigate its usefulness in the diagnosis of other pain-associated rare diseases. This study was registered in the German Clinical Trials Register, No. DRKS00014777 (Deutsches Register klinischer Studien, DRKS), on 01.06.2018.

Therapeutic Plasma Exchange as a Treatment for Autoimmune Neurological Disease

Introduction

Therapeutic plasma exchange (TPE) is commonly used as treatment of certain autoimmune neurological diseases (ANDs), and its main objective is the removal of pathogenic autoantibodies. Our aim was to describe the clinical profile and the experience with the usage of TPE in patients with ANDs at our institution.

Methods

This is an observational retrospective study, including medical records of patients with diagnosis of ANDs who received TPE, between 2011 and 2018. Characteristics of TPE, such as number of cycles, type of replacement solution, and adverse effects, were evaluated. The modified Rankin Scale (mRS) was applied to measure the clinical response after the therapy.

Results

187 patients were included with the following diagnoses: myasthenia gravis (MG), n = 70 (37%); Guillain–Barré syndrome (GBS), n = 53 (28.3%), neuromyelitis optica spectrum disorders (NMOSD), n = 35 (18.7%); chronic inflammatory demyelinating polyneuropathy (CIDP), n = 23 (12.2%); and autoimmune encephalitis (AE), n = 6 (3.2%). The most used types of replacement solution were albumin (n = 131, 70%) and succinylated gelatin (n = 45, 24%). All patients received a median of five cycles (IQR 5-5). Hypotension and hydroelectrolytic disorders were the main complications. After TPE, 99 patients (52.9%) showed improvement in the mRS scores and a statistical significance (p < 0.05) was seen between the admission score and after TPE for every diagnosis except for CIDP.

Conclusion

TPE has an adequate safety profile, and improvement in functionality in treated patients reflects its effectiveness.

Are Repeated Cycles of Intravenous Immunoglobulin Justified in Patients With Poorly Responsive Guillain-Barré Syndrome?

Guillain-Barré syndrome (GBS) is a life-threatening form of inflammatory polyneuropathy. Immunotherapy with intravenous immunoglobulin (IVIG) has been used successfully in the treatment of GBS. In this case report, we present a severe axonal form of GBS that showed improvement after 3 cycles of IVIG. Repeated cycles of IVIG may be an option for treating severe forms of GBS not responding to the first course of such treatment. The recent work suggests that patients who are severely affected and have severe gadolinium enhancement on the magnetic resonance imaging of the spine should be considered for retreatment with IVIG. Although the cost of management was high, the outcome was excellent, which is definitely considered a reasonable approach. This case report is an urgent call for performing large multicenter trials on the use of repeated cycles of IVIG in the management of severe cases of GBS.

Targeting the blood-nerve barrier for the management of immune-mediated peripheral neuropathies

Healthy peripheral nerves encounter, with increased frequency, numerous chemical, biological, and biomechanical forces. Over time and with increasing age, these forces collectively contribute to the pathophysiology of a spectrum of traumatic, metabolic, and/or immune-mediated peripheral nerve disorders. The blood-nerve barrier (BNB) serves as a critical first-line defense against chemical and biologic insults while biomechanical forces are continuously buffered by a dense array of longitudinally orientated epineural collagen fibers exhibiting high-tensile strength. As emphasized throughout this Experimental Neurology Special Issue, the BNB is best characterized as a functionally dynamic multicellular vascular unit comprised of not only highly specialized endoneurial endothelial cells, but also associated perineurial cells, pericytes, Schwann cells, basement membrane, and invested axons. The composition of the BNB, while anatomically distinct, is not functionally dissimilar to that of the well characterized neurovascular unit of the central nervous system. While the BNB lacks a glial limitans and an astrocytic endfoot layer, the primary function of both vascular units is to establish, maintain, and protect an optimal endoneurial (PNS) or interstitial (CNS) fluid microenvironment that is vital for proper neuronal function. Altered endoneurial homeostasis as a secondary consequence of BNB dysregulation is considered an early pathological event in the course of a variety of traumatic, immune-mediated, or metabolically acquired peripheral neuropathies. In this review, emerging experimental advancements targeting the endoneurial microvasculature for the therapeutic management of immune-mediated inflammatory peripheral neuropathies, including the AIDP variant of Guillain-Barré syndrome, are discussed.

Axonal variants of Guillain-Barré syndrome: an update

Axonal variants of Guillain-Barré syndrome (GBS) mainly include acute motor axonal neuropathy, acute motor and sensory axonal neuropathy, and pharyngeal-cervical-brachial weakness. Molecular mimicry of human gangliosides by a pathogen's lipooligosaccharides is a well-established mechanism for Campylobacter jejuni-associated GBS. New triggers of the axonal variants of GBS (axonal GBS), such as Zika virus, hepatitis viruses, intravenous administration of ganglioside, vaccination, and surgery, are being identified. However, the pathogenetic mechanisms of axonal GBS related to antecedent bacterial or viral infections other than Campylobacter jejuni remain unknown. Currently, autoantibody classification and serial electrophysiology are cardinal approaches to differentiate axonal GBS from the prototype of GBS, acute inflammatory demyelinating polyneuropathy. Newly developed technologies, including metabolite analysis, peripheral nerve ultrasound, and feature selection via artificial intelligence are facilitating more accurate diagnosis of axonal GBS. Nevertheless, some key issues, such as genetic susceptibilities, remain unanswered and moreover, current therapies bear limitations. Although several therapies have shown considerable benefits to experimental animals, randomized controlled trials are still needed to validate their efficacy.