Second intravenous immunoglobulin dose in patients with Guillain-Barré syndrome with poor prognosis (SID-GBS): a double-blind, randomised, placebo-controlled trial

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.

New chronic inflammatory demyelinating polyneuropathy/Guillain-Barré syndrome guidelines - impact on clinical practise

PURPOSE OF REVIEW

There is no diagnostic biomarker that can reliably detect Guillain-Barré syndrome (GBS) or chronic inflammatory demyelinating polyneuropathy (CIDP). Diagnosis relies upon integrating key clinical characteristics and relevant supportive data. Consequently, misdiagnosis and delayed diagnosis are common. Diagnostic criteria have proven valuable resources to improve diagnosis, but are underutilized during routine clinical care.

RECENT FINDINGS

In 2021, the EAN/PNS CIDP criteria was published, and were followed by the EAN/PNS GBS criteria in 2023. Both guidelines utilized GRADE methodology to formulate evidence-based recommendations that are intended to be used by adult and paediatric clinicians across diverse care settings to optimize diagnostic accuracy and improve patient outcomes during routine clinical care.

SUMMARY

The EAN/PNS GBS and CIDP criteria detail specific clinical, electrophysiological, and laboratory features that raise diagnostic confidence, and call attention to diagnostic mimics. The sensitivity of EAN/PNS and other modern criteria to detect GBS and CIDP is high, but utilization during clinical practice is low. Complexity is one factor limiting widespread application. Strategies are needed to optimize criteria adoption during routine clinical care such that GBS and CIDP diagnosis can be achieved with greater speed and accuracy.

Efgartigimod in the treatment of Guillain-Barré syndrome

BACKGROUND

Guillain-Barré Syndrome (GBS) is caused by immunoglobulin G (IgG) autoantibodies. Efgartigimod, a human IgG antibody Fc fragment that acts as a natural ligand for the FcRn, can increase IgG degradation, which thus may be a promising therapeutic drug for GBS.

CASE PRESENTATION

The two patients presented with postinfectious and acute flaccid paralysis. On admission, they were bedridden. Nerve conduction studies indicated peripheral neuropathy. GBS was suspected and they are treated with two doses of efgartigimod (10 mg/kg) within 5 days. Their muscle strength improved gradually and 4 weeks after the initial dose, they could walk independently. Following the first dose, Patient 1 complaint of muscle soreness, which subsided the next morning. Patient 2 was intubated due to respiratory failure the day after the initial dose, and did not report other adverse effects.

DISCUSSION

In GBS patients, two doses of efgartigimod (10 mg/kg) were effective in rapidly improving muscle strength, with a satisfactory safety profile. The findings suggest a potential role for efgartigimod in modifying the disease process in GBS patients.

CONCLUSION

Efgartigimod seems effective and safe in the treatment of GBS. This study indicates the potential role of efgartigimod as a novel treatment option for GBS. Well-designed clinical trials should be conducted.

Neuromuscular Emergencies

OBJECTIVE

This article aims to familiarize the reader with the clinical approach, diagnostic considerations, and treatment strategies for patients presenting with abrupt-onset or acutely worsening weakness due to neuromuscular disorders.

LATEST DEVELOPMENTS

Neuromuscular weakness is often the result of an inflammatory process. In recent years, there has been growing recognition of pathologic antibodies that cause neuromuscular injury. This has allowed clinicians to make a more accurate diagnosis. Additionally, neuromuscular junction disorders and myopathies are increasingly identified as the adverse effects of novel anticancer therapies, namely immune checkpoint inhibitors. More data are being incorporated into frameworks for neuroprognostication after neuromuscular emergencies, especially for commonly encountered disorders such as Guillain-Barré syndrome.

ESSENTIAL POINTS

Care of patients with neuromuscular emergencies requires prompt attention to respiratory status. Once supportive measures are in place to protect the airway and facilitate effective ventilation, diagnostic considerations should hinge on appropriate neurologic localization. Aggressive immunosuppression is often required for immune-mediated neuromuscular disorders, and clinicians must be thoughtful in selecting a strategy that best aligns with each patient's risk factors and comorbidities.

Guillain-Barré syndrome after surgery: a literature review

Guillain-Barré syndrome (GBS) is a rare postoperative complication that is sometimes characterized by serious motor weakness and prolonged weaning from mechanical ventilation. Although the exact nature of the relationship between GBS and the surgical procedure is still unclear, there is a clear increased incidence of GBS in post-surgical patients compared to non-surgical patients. GBS after surgery is unique in several ways. The course of post-surgical GBS unfolds more rapidly than in other situations where GBS develops, the condition is often more severe, and respiratory muscles are more commonly involved. Prompt diagnosis and appropriate treatment are essential, and the condition can worsen if treated inappropriately. Postoperative sedation, intubation, and restraint use make the diagnosis of GBS difficult, as the onset of symptoms of weakness or numbness in those contexts are not obvious. GBS is often misdiagnosed, being attributed to other postoperative complications, and subsequently mishandled. The lack of relevant information further obscures the clinical picture. We sought to better understand post-surgical GBS by performing an analysis of the relevant literature, focusing on clearly documenting the clinical characteristics, diagnosis, and management of GBS that emerges following surgery. We underscore the importance of physicians being aware of the possibility of GBS after major surgery and of performing a variety of laboratory clinical investigations early on in suspected cases.

Dynamics and prognostic value of serum neurofilament light chain in Guillain-Barré syndrome

BACKGROUND

Neurofilament light chain (NfL) is a biomarker for axonal damage in several neurological disorders. We studied the longitudinal changes in serum NfL in patients with Guillain-Barré syndrome (GBS) in relation to disease severity, electrophysiological subtype, treatment response, and prognosis.

METHODS

We included patients with GBS who participated in a double-blind, randomised, placebo-controlled trial that evaluated the effects of a second course of intravenous immunoglobulin (IVIg) on clinical outcomes. Serum NfL levels were measured before initiation of treatment and at one, two, four, and twelve weeks using a Simoa HD-X Analyzer. Serum NfL dynamics were analysed using linear mixed-effects models. Logistic regression was employed to determine the associations of serum NfL with clinical outcome and the prognostic value of serum NfL after correcting for known prognostic markers included in the modified Erasmus GBS Outcome Score (mEGOS).

FINDINGS

NfL levels were tested in serum from 281 patients. Serum NfL dynamics were associated with disease severity and electrophysiological subtype. Strong associations were found between high levels of serum NfL at two weeks and inability to walk unaided at four weeks (OR = 1.74, 95% CI = 1.27-2.45), and high serum NfL levels at four weeks and inability to walk unaided at 26 weeks (OR = 2.79, 95% CI = 1.72-4.90). Baseline serum NfL had the most significant prognostic value for ability to walk, independent of predictors included in the mEGOS. The time to regain ability to walk unaided was significantly longer for patients with highest serum NfL levels at baseline (p = 0.0048) and week 2 (p < 0.0001). No differences in serum NfL were observed between patients that received a second IVIg course vs. IVIg and placebo.

INTERPRETATION

Serum NfL levels are associated with disease severity, axonal involvement, and poor outcome in GBS. Serum NfL potentially represents a biomarker to monitor neuronal damage in GBS and an intermediate endpoint to evaluate the effects of treatment.

FUNDING

Prinses Beatrix Spierfonds W.OR19-24.

What Is in the Literature

ABSTRACT

This issue of What is in the Literature focuses on the Guillain-Barré syndrome. Guillain-Barré syndrome is a monophasic illness, and there is new information about precipitating factors, changes in nerve conduction studies over time, potential biomarkers, optimal treatment, and features in uncommon patient populations.

Guillain-Barré syndrome: immunopathogenesis and therapeutic targets

INTRODUCTION

Guillain-Barré syndrome (GBS) is a group of acute immune-mediated disorders in the peripheral nervous system. Both infectious and noninfectious factors are associated with GBS, which may act as triggers of autoimmune responses leading to neural damage and dysfunction.

AREAS COVERED

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and its vaccines as well as flaviviruses have been associated with GBS, although a robust conclusion has yet to be reached. Immunomodulatory treatments, including intravenous immunoglobulins (IVIg) and plasma exchange (PE), have long been the first-line therapies for GBS. Depending on GBS subtype and severity at initial presentation, the efficacy of IVIg and PE can be variable. Several new therapies showing benefits to experimental animals merit further investigation before translation into clinical practice. We review the state-of-the-art knowledge on the immunopathogenesis of GBS in the context of coronavirus disease 2019 (COVID-19). Immunomodulatory therapies in GBS, including IVIg, PE, corticosteroids, and potential therapies, are summarized.

EXPERT OPINION

The association with SARS-CoV-2 remains uncertain, with geographical differences that are difficult to explain. Evidence and guidelines are lacking for the decision-making of initiating immunomodulatory therapies in mildly affected patients or patients with regional subtypes of GBS.

[Prospect of novel therapies in immune-mediated neuropathies]

The efficacy of immunotherapies such as steroids, plasmapheresis, and intravenous immunoglobulin have been proven in various immune-mediated neuropathies. However, these treatments sometimes lack the efficacy in a part of patients with the immune-mediated neuropathies. In addition, anti-myelin associated glycoprotein (MAG) neuropathy is usually refractory to the treatments. Recently, novel therapies targeting a molecule which are associated with pathogenesis of immune-mediated diseases, have been developed. These molecularly targeted therapies are notable in immune-mediated neuropathies as novel drug candidates. In the present article, current treatments and future prospect of novel therapies in immune-mediated neuropathies will be reviewed.

Current status of Guillain-Barré syndrome (GBS) in China: a 10-year comprehensive overview

Guillain-Barré syndrome (GBS) is an acute inflammatory polyradiculoneuropathy; a disease involving the peripheral nervous system which is the most common cause of acute flaccid paralysis worldwide. So far, it is still lack of a comprehensive overview and understanding of the national epidemiological, clinical characteristics, and the risk factors of GBS in China, as well as differences between China and other countries and regions in these respects. With the global outbreak of the coronavirus disease 2019 (COVID-19), an epidemiological or phenotypic association between severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection and GBS has attracted great attention. In this review, we outlined the current clinical data of GBS in China by retrieving literature, extracting and synthesizing the data of GBS in China from 2010 to 2021. Besides, we compared the characteristics of epidemiology, preceding events and clinical profiles of GBS between China and other countries and regions. Furthermore, in addition to conventional intravenous immunoglobulin (IVIG) and plasma exchange (PE) therapy, the potential therapeutic effects with novel medications in GBS, such as complement inhibitors, etc., have become the research focus in treatments. We found that epidemiological and clinical findings of GBS in China are approximately consistent with those in the International GBS Outcome Study (IGOS) cohort. We provided an overall picture of the present clinical status of GBS in China and summarized the global research progress of GBS, aiming to further understand the characteristics of GBS and improve the future work of GBS worldwide, especially in countries with the middle and low incomes.

European Academy of Neurology/Peripheral Nerve Society Guideline on diagnosis and treatment of Guillain-Barré syndrome

Guillain-Barré syndrome (GBS) is an acute polyradiculoneuropathy. Symptoms may vary greatly in presentation and severity. Besides weakness and sensory disturbances, patients may have cranial nerve involvement, respiratory insufficiency, autonomic dysfunction and pain. To develop an evidence-based guideline for the diagnosis and treatment of GBS, using Grading of Recommendations, Assessment, Development and Evaluation (GRADE) methodology a Task Force (TF) of the European Academy of Neurology (EAN) and the Peripheral Nerve Society (PNS) constructed 14 Population/Intervention/Comparison/Outcome questions (PICOs) covering diagnosis, treatment and prognosis of GBS, which guided the literature search. Data were extracted and summarised in GRADE Summaries of Findings (for treatment PICOs) or Evidence Tables (for diagnostic and prognostic PICOs). Statements were prepared according to GRADE Evidence-to-Decision (EtD) frameworks. For the six intervention PICOs, evidence-based recommendations are made. For other PICOs, good practice points (GPPs) are formulated. For diagnosis, the principal GPPs are: GBS is more likely if there is a history of recent diarrhoea or respiratory infection; CSF examination is valuable, particularly when the diagnosis is less certain; electrodiagnostic testing is advised to support the diagnosis; testing for anti-ganglioside antibodies is of limited clinical value in most patients with typical motor-sensory GBS, but anti-GQ1b antibody testing should be considered when Miller Fisher syndrome (MFS) is suspected; nodal-paranodal antibodies should be tested when autoimmune nodopathy is suspected; MRI or ultrasound imaging should be considered in atypical cases; and changing the diagnosis to acute-onset chronic inflammatory demyelinating polyradiculoneuropathy (A-CIDP) should be considered if progression continues after 8 weeks from onset, which occurs in around 5% of patients initially diagnosed with GBS. For treatment, the TF recommends intravenous immunoglobulin (IVIg) 0.4 g/kg for 5 days, in patients within 2 weeks (GPP also within 2-4 weeks) after onset of weakness if unable to walk unaided, or a course of plasma exchange (PE) 12-15 L in four to five exchanges over 1-2 weeks, in patients within 4 weeks after onset of weakness if unable to walk unaided. The TF recommends against a second IVIg course in GBS patients with a poor prognosis; recommends against using oral corticosteroids, and weakly recommends against using IV corticosteroids; does not recommend PE followed immediately by IVIg; weakly recommends gabapentinoids, tricyclic antidepressants or carbamazepine for treatment of pain; does not recommend a specific treatment for fatigue. To estimate the prognosis of individual patients, the TF advises using the modified Erasmus GBS outcome score (mEGOS) to assess outcome, and the modified Erasmus GBS Respiratory Insufficiency Score (mEGRIS) to assess the risk of requiring artificial ventilation. Based on the PICOs, available literature and additional discussions, we provide flow charts to assist making clinical decisions on diagnosis, treatment and the need for intensive care unit admission.

European Academy of Neurology/Peripheral Nerve Society Guideline on diagnosis and treatment of Guillain-Barré syndrome

Guillain-Barré syndrome (GBS) is an acute polyradiculoneuropathy. Symptoms may vary greatly in presentation and severity. Besides weakness and sensory disturbances, patients may have cranial nerve involvement, respiratory insufficiency, autonomic dysfunction and pain. To develop an evidence-based guideline for the diagnosis and treatment of GBS, using Grading of Recommendations, Assessment, Development and Evaluation (GRADE) methodology, a Task Force (TF) of the European Academy of Neurology (EAN) and the Peripheral Nerve Society (PNS) constructed 14 Population/Intervention/Comparison/Outcome questions (PICOs) covering diagnosis, treatment and prognosis of GBS, which guided the literature search. Data were extracted and summarised in GRADE Summaries of Findings (for treatment PICOs) or Evidence Tables (for diagnostic and prognostic PICOs). Statements were prepared according to GRADE Evidence-to-Decision (EtD) frameworks. For the six intervention PICOs, evidence-based recommendations are made. For other PICOs, good practice points (GPPs) are formulated. For diagnosis, the principal GPPs are: GBS is more likely if there is a history of recent diarrhoea or respiratory infection; CSF examination is valuable, particularly when the diagnosis is less certain; electrodiagnostic testing is advised to support the diagnosis; testing for anti-ganglioside antibodies is of limited clinical value in most patients with typical motor-sensory GBS, but anti-GQ1b antibody testing should be considered when Miller Fisher syndrome (MFS) is suspected; nodal-paranodal antibodies should be tested when autoimmune nodopathy is suspected; MRI or ultrasound imaging should be considered in atypical cases; and changing the diagnosis to acute-onset chronic inflammatory demyelinating polyradiculoneuropathy (A-CIDP) should be considered if progression continues after 8 weeks from onset, which occurs in around 5% of patients initially diagnosed with GBS. For treatment, the TF recommends intravenous immunoglobulin (IVIg) 0.4 g/kg for 5 days, in patients within 2 weeks (GPP also within 2-4 weeks) after onset of weakness if unable to walk unaided, or a course of plasma exchange (PE) 12-15 L in four to five exchanges over 1-2 weeks, in patients within 4 weeks after onset of weakness if unable to walk unaided. The TF recommends against a second IVIg course in GBS patients with a poor prognosis; recommends against using oral corticosteroids, and weakly recommends against using IV corticosteroids; does not recommend PE followed immediately by IVIg; weakly recommends gabapentinoids, tricyclic antidepressants or carbamazepine for treatment of pain; does not recommend a specific treatment for fatigue. To estimate the prognosis of individual patients, the TF advises using the modified Erasmus GBS outcome score (mEGOS) to assess outcome, and the modified Erasmus GBS Respiratory Insufficiency Score (mEGRIS) to assess the risk of requiring artificial ventilation. Based on the PICOs, available literature and additional discussions, we provide flow charts to assist making clinical decisions on diagnosis, treatment and the need for intensive care unit admission.

Guillain-Barré Syndrome

OBJECTIVE

This article summarizes the clinical features, diagnostic criteria, differential diagnosis, pathogenesis, and prognosis of Guillain-Barré syndrome (GBS), with insights into the current and future diagnostic and therapeutic interventions for this neuromuscular syndrome.

LATEST DEVELOPMENTS

GBS is an acute, inflammatory, immune-mediated polyradiculoneuropathy that encompasses many clinical variants and divergent pathogenic mechanisms that lead to axonal, demyelinating, or mixed findings on electrodiagnostic studies. The type of antecedent infection, the development of pathogenic cross-reactive antibodies via molecular mimicry, and the location of the target gangliosides affect the subtype and severity of the illness. The data from the International GBS Outcome Study have highlighted regional variances, provided new and internationally validated prognosis tools that are beneficial for counseling, and introduced a platform for discussion of GBS-related open questions. New research has been undertaken, including research on novel diagnostic and therapeutic biomarkers, which may lead to new therapies.

ESSENTIAL POINTS

GBS is among the most frequent life-threatening neuromuscular emergencies in the world. At least 20% of patients with GBS have a poor prognosis and significant residual deficits despite receiving available treatments. Research is ongoing to further understand the pathogenesis of the disorder, find new biomarkers, and develop more effective and specific treatments.

Neuroprognostication: Guillain-Barré Syndrome

Guillain-Barré syndrome is an immune-mediated disease of the peripheral nerves characterized by rapidly progressing symmetric weakness, areflexia, and albuminocytological dissociation. Most patients reach their nadir within 2 weeks. Disease severity can be mild to severe, with 20% of patients requiring mechanical ventilation. Intravenous immunoglobulin and plasma exchange are equally effective treatments. Monitoring strength, respiratory function, blood pressure, and heart rate, as well as pain management and rehabilitative therapy are important aspects of management. About 20% of patients require assistance to walk at 6 months. Older age, preceding diarrhea, and lower Medical Research Council (MRC) sum scores predict poor outcome. Death from cardiovascular and respiratory complications can occur in the acute or recovery phases of the illness in 3 to 7% of the patients. Risk factors for mortality include advanced age and disease severity at onset. Neuropathic pain, weakness, and fatigue can be residual symptoms; risk factors for these include axonal loss, sensory involvement, and severity of illness.

Safety and Tolerability of Intravenous Immunoglobulin in Chronic Inflammatory Demyelinating Polyneuropathy: Results of the ProCID Study

BACKGROUND AND AIMS

The ProCID study evaluated the efficacy and safety of three doses of a 10% liquid intravenous immunoglobulin (IVIg) preparation (panzyga®) in patients with chronic inflammatory demyelinating polyneuropathy (CIDP). This report describes the safety findings.

METHODS

Patients were randomised to receive a 2.0 g/kg induction dose followed by maintenance doses of either 0.5, 1.0 or 2.0 g/kg IVIg every 3 weeks over 24 weeks.

RESULTS

All 142 enrolled patients were included in the safety analyses. In total, 286 treatment-emergent adverse events (TEAEs) were reported in 89 patients, of which 173 (60.5%) were considered treatment-related. Most TEAEs were of mild severity. Eleven serious TEAEs were reported in 6 patients. Two serious TEAEs in one patient (headache and vomiting) were considered related to treatment, which resolved without study discontinuation. No treatment-related thrombotic events, haemolytic transfusion reactions or deaths occurred. One patient discontinued the study due to a TEAE (allergic dermatitis) probably related to IVIg. Headache was the only dose-dependent TEAE, with incidences ranging from 2.9 to 23.7%, the incidence of all other TEAEs was similar across treatment groups. Most TEAEs were associated with the induction dose infusion, and the rate of TEAEs decreased thereafter. The median (IQR) daily IVIg dose was 78 (64-90) g, and 94.4% of patients tolerated the maximal infusion rate of 0.12 ml/kg/min without pre-medication.

INTERPRETATION

Infusions of 10% IVIg at doses up to 2.0 g/kg with high infusion rates were safe and well tolerated in patients with CIDP.

CLINICAL TRIAL NUMBERS

EudraCT 2015-005443-14, NCT02638207.

Emerging biomarkers to predict clinical outcomes in Guillain-Barré syndrome

INTRODUCTION

Guillain-Barré syndrome (GBS) is an immune-mediated poly(radiculo)neuropathy with a variable clinical outcome. Identifying patients who are at risk of suffering from long-term disabilities is a great challenge. Biomarkers are useful to confirm diagnosis, monitor disease progression, and predict outcome.

AREAS COVERED

The authors provide an overview of the diagnostic and prognostic biomarkers for GBS, which are useful for establishing early treatment strategies and follow-up care plans.

EXPERT OPINION

Detecting patients at risk of developing a severe outcome may improve management of disease progression and limit potential complications. Several clinical factors are associated with poor prognosis: higher age, presence of diarrhea within 4 weeks of symptom onset, rapid and severe weakness progression, dysautonomia, decreased vital capacity and facial, bulbar, and neck weakness. Biological, neurophysiological and imaging measures of unfavorable outcome include multiple anti-ganglioside antibodies elevation, increased serum and CSF neurofilaments light (NfL) and heavy chain, decreased NfL CSF/serum ratio, hypoalbuminemia, nerve conduction study with early signs of demyelination or axonal loss and enlargement of nerve cross-sectional area on ultrasound. Depicting prognostic biomarkers aims at predicting short-term mortality and need for cardio-pulmonary support, long-term patient functional outcome, guiding treatment decisions and monitoring therapeutic responses in future clinical trials.

The neutrophil-to-lymphocyte ratio as a prognostic biomarker in Guillain-Barre syndrome: a systematic review with meta-analysis

Background and objectives

Guillain-Barre syndrome (GBS) is an immune-mediated neuropathy. This has raised the possibility that the neutrophil-lymphocyte ratio (NLR) may be a biomarker of its activity. We conducted a systematic review and meta-analysis to summarize the evidence of NLR as a potential biomarker for GBS.

Methods

We systematically searched databases (PubMed, Ovid-Medline, Embase, Scopus, Web of Science, SciELO Citation Index, LILACS, and Google Scholar) until October 2021 for studies evaluating pre-treatment NLR values in GBS patients. A meta-analysis using a random-effects model to estimate pooled effects was realized for each outcome and a narrative synthesis when this was not possible. Subgroup and sensitivity analysis were realized. GRADE criteria were used to identify the certainty of evidence for each result.

Results

Ten studies from 745 originally included were selected. Regarding GBS patients versus healthy controls, a meta-analysis of six studies (968 patients) demonstrated a significant increase in NLR values in GBS patients (MD: 1.76; 95% CI: 1.29, 2.24; I2 = 86%) with moderate certainty due to heterogeneity of GBS diagnosis criteria used. Regarding GBS prognosis, assessed by Hughes Score ≥ 3, NLR had a sensitivity between 67.3 and 81.5 and a specificity between 67.3 and 87.5 with low certainty due to imprecision, and heterogeneity. In relation to respiratory failure, NLR had a sensitivity of 86.5 and specificity of 68.2 with high and moderate certainty, respectively.

Discussion

With moderate certainty, mean NLR is higher in GBS patients compared to healthy controls. Furthermore, we found that NLR could be a prognostic factor for disability and respiratory failure with low and moderate certainty, respectively. These results may prove useful for NLR in GBS patients; however, further research is needed.

Systematic review registration

https://www.crd.york.ac.uk/PROSPERO/, identifier: CRD42021285212.

Molecular, Electrophysiological, and Ultrasonographic Differences in Selected Immune-Mediated Neuropathies with Therapeutic Implications

The spectrum of immune-mediated neuropathies is broad and the different subtypes are still being researched. With the numerous subtypes of immune-mediated neuropathies, establishing the appropriate diagnosis in normal clinical practice is challenging. The treatment of these disorders is also troublesome. The authors have undertaken a literature review of chronic inflammatory demyelinating polyradiculoneuropathy (CIDP), Guillain-Barre syndrome (GBS) and multifocal motor neuropathy (MMN). The molecular, electrophysiological and ultrasound features of these autoimmune polyneuropathies are analyzed, highlighting the differences in diagnosis and ultimately treatment. The immune dysfunction can lead to damage to the peripheral nervous system. In practice, it is suspected that these disorders are caused by autoimmunity to proteins located in the node of Ranvier or myelin components of peripheral nerves, although disease-associated autoantibodies have not been identified for all disorders. The electrophysiological presence of conduction blocks is another important factor characterizing separate subgroups of treatment-naive motor neuropathies, including multifocal CIDP (synonyms: multifocal demyelinating neuropathy with persistent conduction block), which differs from multifocal motor neuropathy with conduction block (MMN) in both responses to treatment modalities and electrophysiological features. Ultrasound is a reliable method for diagnosing immune-mediated neuropathies, particularly when alternative diagnostic examinations yield inconclusive results. In overall terms, the management of these disorders includes immunotherapy such as corticosteroids, intravenous immunoglobulin or plasma exchange. Improvements in clinical criteria and the development of more disease-specific immunotherapies should expand the therapeutic possibilities for these debilitating diseases.

Serum C3 complement levels predict prognosis and monitor disease activity in Guillain-Barré syndrome

OBJECTIVE

Biomarkers are needed to predict prognosis and disease activity in patients with Guillain-Barré syndrome (GBS). The complement system is a key player in the pathogenesis of GBS. This study aimed to assess the potential utility of serum complement proteins as novel biomarkers in GBS.

METHODS

We reviewed the medical records of 76 GBS patients with C3 and C4 measurements during hospitalization between 2010 and 2021. Clinical outcomes were correlated with baseline serum C3, C4, and seven additional predictors: four existing biomarkers (GM1, albumin, immunoglobulin G, neutrophil-lymphocyte ratio) and three clinical factors from the modified Erasmus GBS outcome score model. Five complement activation products (C3a, C4a, C5a, soluble C5b-9, factor Bb) were measured in 35 patients and were compared with C3 and C4 levels. Longitudinal changes in C3 and C4 levels were compared with the disease course in 12 patients.

RESULTS

Higher C3, but not C4, was associated with poorer outcomes: lower Medical Research Council sum scores (MRCSS), higher GBS disability score (GBSDS), longer hospitalization, and more frequent treatment-related fluctuations. Age, MRCSS at admission, and baseline serum C3 were significant independent indicators of 1- and 3-month GBSDS. We found that C3 was positively correlated with C3a (r = 0.32) and C5a (r = 0.37), which indicates an activated complement cascade with high C3. Longitudinal change of C3 coincided with clinical severity of the disease course.

INTERPRETATION

This study highlights the use of serum C3 as a novel mechanistic biomarker in GBS. Larger prospective studies are needed to validate our findings.

Acute/chronic inflammatory polyradiculoneuropathy

Autoimmune neuropathy may present acutely or with a more progressive and/or relapsing and remitting course. Acute inflammatory neuropathy or Guillain-Barré syndrome (GBS) has variable presentations but by far the most common is acute inflammatory demyelinating polyradiculoneuropathy which is characterized by rapidly progressive proximal and distal symmetric weakness, sensory loss, and depressed reflexes. The most common chronic autoimmune neuropathy is chronic inflammatory demyelinating polyradiculoneuropathy, which in its most typical form is clinically similar to acute inflammatory demyelinating polyradiculoneuropathy (proximal and distal symmetric weakness, sensory loss, and depressed reflexes) but differs in that onset is much more gradual, i.e., over at least 8 weeks. While the majority of GBS cases result from a postinfectious activation of the immune system, presumably in a genetically susceptible host, less is understood regarding the etiopathogenesis of chronic inflammatory demyelinating polyradiculoneuropathy. Both acute and chronic forms of these inflammatory neuropathies are driven by some combination of innate and adaptive immune pathways, with differing contributions depending on the neuropathy subtype. Both disorders are largely clinical diagnoses, but diagnostic tools are available to confirm the diagnosis, prognosticate, detect variant forms, and rule out mimics. Given the autoimmune underpinnings of both disorders, immunosuppressive and immunomodulating treatments are typically given in both diseases; however, they differ in their response to treatment.

Course and Treatment of a Rare Neurological Sequelae After COVID-19: Miller Fisher Syndrome

Reports of COVID-19 infection detailing its symptoms and outcomes point to its effects systemically, including that of the nervous system, such as the rare Miller Fisher syndrome (MFS). In this report, we identified a 43-year-old Caribbean man who arrived in the USA with ataxia and ascending bilateral lower extremity weakness after COVID-19 infection. Before arrival, the patient was diagnosed with Guillain-Barré syndrome (GBS). He was treated with IV methylprednisolone and a round of IV immunoglobulin (IVIG); however, he showed a minimal response. Upon admission to our ED, he had severe tachypnea and flaccid symmetrical quadriparesis combined with areflexia. Moreover, he had begun to exhibit signs of multiple cranial nerve palsies, including ophthalmoplegia and facial diplegia. Additionally, his laboratory cerebrospinal fluid (CSF) analysis was grossly normal. Therefore, he was diagnosed with MFS. Furthermore, he developed acute depression and exhibited signs of mania. The patient was treated with IV methylprednisolone and the second round of a five-day course of IVIG, resulting in marked clinical improvement. This case highlights the need for a multidisciplinary care approach in patients with MFS. It also points to the possible benefit of multiple IVIG rounds in MFS patients who do not improve after the first course.

Population Pharmacokinetic Modelling of Intravenous Immunoglobulin Treatment in Patients with Guillain-Barré Syndrome

Background and Objective

Intravenous immunoglobulin (IVIg) at a standard dosage is the treatment of choice for Guillain–Barré syndrome. The pharmacokinetics, however, is highly variable between patients, and a rapid clearance of IVIg is associated with poor recovery. We aimed to develop a model to predict the pharmacokinetics of a standard 5-day IVIg course (0.4 g/kg/day) in patients with Guillain–Barré syndrome.

Methods

Non-linear mixed-effects modelling software (NONMEM^®) was used to construct a pharmacokinetic model based on a model-building cohort of 177 patients with Guillain–Barré syndrome, with a total of 589 sequential serum samples tested for total immunoglobulin G (IgG) levels, and evaluated on an independent validation cohort that consisted of 177 patients with Guillain–Barré syndrome with 689 sequential serum samples.

Results

The final two-compartment model accurately described the daily increment in serum IgG levels during a standard IVIg course; the initial rapid fall and then a gradual decline to steady-state levels thereafter. The covariates that increased IgG clearance were a more severe disease (as indicated by the Guillain–Barré syndrome disability score) and concomitant methylprednisolone treatment. When the current dosing regimen was simulated, the percentage of patients who reached a target ∆IgG > 7.3 g/L at 2 weeks decreased from 74% in mildly affected patients to only 33% in the most severely affected and mechanically ventilated patients (Guillain–Barré syndrome disability score of 5).

Conclusions

This is the first population-pharmacokinetic model for standard IVIg treatment in Guillain–Barré syndrome. The model provides a new tool to predict the pharmacokinetics of alternative regimens of IVIg in Guillain–Barré syndrome to design future trials and personalise treatment.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40262-022-01136-z.

Immunoglobulin and Monoclonal Antibody Therapies in Guillain-Barré Syndrome

Guillain-Barré syndrome (GBS) is an acute autoimmune polyradiculoneuropathy affecting 1-2 subjects per 100,000 every year worldwide. It causes, in its classic form, symmetric weakness in the proximal and distal limb muscles with common involvement of the cranial nerves, particularly facial weakness. Respiratory function is compromised in a case in four. Randomised controlled trials have demonstrated the benefit of therapeutic plasma exchange in hastening time to recovery. Intravenous immunoglobulin was subsequently shown to be as efficacious as plasma exchange in adult subjects. In children, few trials have shown the benefit of intravenous immunoglobulin versus supportive care. Pharmacokinetic studies suggested a relationship between increase in immunoglobulin G level post-infusion and outcome, implying administration of larger doses may be beneficial in subjects with poor prognosis. However, a subsequent trial of a second dose of immunoglobulin in such subjects failed to show improved outcome, while demonstrating a higher risk of thromboembolic side-effects. Monoclonal antibody therapy has more recently been investigated for GBS, after multiple studies in animal models, with different agents and variable postulated mechanisms of action. Eculizumab, a humanised monoclonal antibody against the complement protein C5, was tested in in two randomised, double-blind, placebo-controlled phase 2 trials. Neither showed benefit versus immunoglobulins alone on disability level at 4 weeks, although one study importantly suggested possible, clinically highly relevant, late effects on normalising function. A phase 3 trial is in progress. Preliminary results of a placebo-controlled ongoing study of ANX005, a humanised recombinant antibody against C1q inhibiting the complement cascade, have been promising.

The challenge of diagnosing Guillain–Barre syndrome in patients with COVID-19 in the intensive care unit

Various neurological complications have been described in COVID-19 patients, especially Guillain–Barre syndrome (GBS). The underlying mechanisms on the association between SARS-CoV-2 infection and GBS remain unclear, but several hypotheses have been proposed. It seems that post-SARS-CoV-2 GBS shares many characteristics with classic post-infectious GBS; however, it may occur in sedated and intubated patients hospitalized in the intensive care unit for SARS-CoV-2 acute respiratory distress syndrome, which presents challenges in the diagnosis and treatment of GBS. In this study, we describe three cases of post-SARS-CoV-2 GBS that were hospitalized in the intensive care unit.

To be, or not to be… Guillain-Barré Syndrome

Guillain-Barré Syndrome (GBS) is currently the most frequent cause of acute flaccid paralysis on a global scale, being an autoimmune disorder wherein demyelination of the peripheral nerves occurs. Its main clinical features are a symmetrical ascending muscle weakness with reduced osteotendinous reflexes and variable sensory involvement. GBS most commonly occurs after an infection, especially viral (including COVID-19), but may also transpire after immunization with certain vaccines or in the development of specific malignancies. Immunoglobulins, plasmapheresis, and glucocorticoids represent the principal treatment modalities, however patients with severe disease progression may require supportive therapy in an intensive care unit. Due to its symptomology, which overlaps with numerous neurological and infectious illnesses, the diagnosis of GBS may often be misattributed to pathologies that are essentially different from this syndrome. Moreover, many of these require specific treatment methods distinct to those recommended for GBS, in lack of which the prognosis of the patient is drastically affected. Such diseases include exposure to toxins either environmental or foodborne, central nervous system infections, metabolic or serum ion alterations, demyelinating pathologies, or even conditions amenable to neurosurgical intervention. This extensive narrative review aims to systematically and comprehensively tackle the most notable and challenging differential diagnoses of GBS, emphasizing on the clinical discrepancies between the diseases, the appropriate paraclinical investigations, and suitable management indications.

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.

Update on Intravenous Immunoglobulin in Neurology: Modulating Neuro-autoimmunity, Evolving Factors on Efficacy and Dosing and Challenges on Stopping Chronic IVIg Therapy

In the last 25 years, intravenous immunoglobulin (IVIg) has had a major impact in the successful treatment of previously untreatable or poorly controlled autoimmune neurological disorders. Derived from thousands of healthy donors, IVIg contains IgG1 isotypes of idiotypic antibodies that have the potential to bind pathogenic autoantibodies or cross-react with various antigenic peptides, including proteins conserved among the "common cold"-pre-pandemic coronaviruses; as a result, after IVIg infusions, some of the patients' sera may transiently become positive for various neuronal antibodies, even for anti-SARS-CoV-2, necessitating caution in separating antibodies derived from the infused IVIg or acquired humoral immunity. IVIg exerts multiple effects on the immunoregulatory network by variably affecting autoantibodies, complement activation, FcRn saturation, FcγRIIb receptors, cytokines, and inflammatory mediators. Based on randomized controlled trials, IVIg is approved for the treatment of GBS, CIDP, MMN and dermatomyositis; has been effective in, myasthenia gravis exacerbations, and stiff-person syndrome; and exhibits convincing efficacy in autoimmune epilepsy, neuromyelitis, and autoimmune encephalitis. Recent evidence suggests that polymorphisms in the genes encoding FcRn and FcγRIIB may influence the catabolism of infused IgG or its anti-inflammatory effects, impacting on individualized dosing or efficacy. For chronic maintenance therapy, IVIg and subcutaneous IgG are effective in controlled studies only in CIDP and MMN preventing relapses and axonal loss up to 48 weeks; in practice, however, IVIg is continuously used for years in all the aforementioned neurological conditions, like is a "forever necessary therapy" for maintaining stability, generating challenges on when and how to stop it. Because about 35-40% of patients on chronic therapy do not exhibit objective neurological signs of worsening after stopping IVIg but express subjective symptoms of fatigue, pains, spasms, or a feeling of generalized weakness, a conditioning effect combined with fear that discontinuing chronic therapy may destabilize a multi-year stability status is likely. The dilemmas of continuing chronic therapy, the importance of adjusting dosing and scheduling or periodically stopping IVIg to objectively assess necessity, and concerns in accurately interpreting IVIg-dependency are discussed. Finally, the merit of subcutaneous IgG, the ineffectiveness of IVIg in IgG4-neurological autoimmunities, and genetic factors affecting IVIg dosing and efficacy are addressed.

Real-world treatment of adult patients with Guillain-Barré syndrome over the last two decades

This study investigated treatment characteristics of Guillain-Barré syndrome (GBS) in a real-world setting between 2000 and 2019. We analyzed clinical improvement between nadir and last follow-up in patients with severe GBS (defined as having a GBS disability scale > 2 at nadir) and aimed to detect clinical factors associated with multiple treatments. We included 121 patients (74 male; median age 48 [IQR 35-60]) with sensorimotor (63%), pure motor (15%), pure sensory (10%) and localized GBS (6%) as well as Miller Fisher syndrome (6%). 44% of patients were severely affected. All but one patient received at least one immunomodulatory treatment with initially either intravenous immunoglobulins (88%), plasma exchange (10%) or corticosteroids (1%), and 25% of patients received more than one treatment. Severe GBS but not age, sex, GBS subtype or date of diagnosis was associated with higher odds to receive more than one treatment (OR 4.22; 95%CI 1.36-13.10; p = 0.01). Receiving multiple treatments had no adjusted effect (OR 1.30, 95%CI 0.31-5.40, p = 0.72) on clinical improvement between nadir and last follow-up in patients with severe GBS. This treatment practice did not change over the last 20 years.