Treatment of Guillain-Barré syndrome with anti-T cell monoclonal antibodies

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.

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.

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.

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.

Pharmacological treatment other than corticosteroids, intravenous immunoglobulin and plasma exchange for Guillain-Barré syndrome

BACKGROUND

Plasma exchange and intravenous immunoglobulin, but not corticosteroids, are beneficial in Guillain-Barré syndrome (GBS). The efficacy of other pharmacological agents is unknown. This review was first published in 2011 and previously updated in 2013, and 2016.

OBJECTIVES

To assess the effects of pharmacological agents other than plasma exchange, intravenous immunoglobulin and corticosteroids for GBS.

SEARCH METHODS

On 28 October 2019, we searched the Cochrane Neuromuscular Specialised Register, CENTRAL, MEDLINE, and Embase for treatments for GBS. We also searched clinical trials registries.

SELECTION CRITERIA

We included all randomised controlled trials (RCTs) or quasi-RCTs of acute GBS (within four weeks from onset) of all types and degrees of severity, and in individuals of all ages. We discarded trials that investigated only corticosteroids, intravenous immunoglobulin or plasma exchange. We included other pharmacological treatments or combinations of treatments compared with no treatment, placebo or another treatment.

DATA COLLECTION AND ANALYSIS

We followed standard Cochrane methodology.

MAIN RESULTS

We found six trials of five different interventions eligible for inclusion in this review. The trials were conducted in hospitals in Canada, China, Germany, Japan and the UK, and included 151 participants in total. All trials randomised participants aged 16 years and older (mean or median age in the trials ranged from 36 to 57 years in the intervention groups and 34 to 60 years in the control groups) with severe GBS, defined by the inability to walk unaided. One trial also randomised patients with mild GBS who were still able to walk unaided. We identified two new trials at this update.The primary outcome measure for this review was improvement in disability grade four weeks after randomisation. Four of six trials had a high risk of bias in at least one respect. We assessed all evidence for the outcome mean improvement in disability grade as very low certainty, which means that we were unable to draw any conclusions from the data. One RCT with 19 participants compared interferon beta-1a (IFNb-1a) and placebo. It is uncertain whether IFNb-1a improves disability after four weeks (mean difference (MD) -0.1; 95% CI -1.58 to 1.38; very low-certainty evidence). A trial with 10 participants compared brain-derived neurotrophic factor (BNDF) and placebo. It is uncertain whether BDNF improves disability after four weeks (MD 0.75; 95% CI -1.14 to 2.64; very low-certainty evidence). A trial with 37 participants compared cerebrospinal fluid (CSF) filtration and plasma exchange. It is uncertain whether CSF filtration improves disability after four weeks (MD 0.02; 95% CI -0.62 to 0.66; very low-certainty evidence). One trial that compared the Chinese herbal medicine tripterygium polyglycoside with corticosteroids with 43 participants did not report the risk ratio (RR) for an improvement by one or more disability grade after four weeks, but did report improvement after eight weeks. It is uncertain whether tripterygium polyglycoside improves disability after eight weeks (RR 1.47; 95% CI 1.02 to 2.11; very low-certainty evidence). We performed a meta-analysis of two trials comparing eculizumab and placebo with 41 participants. It is uncertain whether eculizumab improves disability after four weeks (MD -0.23; 95% CI -1.79 to 1.34; very low-certainty evidence). Serious adverse events were uncommon in each of the trials and evidence was graded as either low or very low. It is uncertain whether serious adverse events were more common with IFNb-1a versus placebo (RR 0.92, 95% CI 0.23 to 3.72; 19 participants), BNDF versus placebo (RR 1.00, 95% CI 0.28 to 3.54; 10 participants) or CSF filtration versus plasma exchange (RR 0.13, 95% CI 0.01 to 2.25; 37 participants). The trial of tripterygium polyglycoside did not report serious adverse events. There may be no clear difference in the number of serious adverse events after eculizumab compared to placebo (RR 1.90, 0.34 to 10.50; 41 participants). We found no clinically important differences in any of the outcome measures selected for this review in any of the six trials. However, sample sizes were small and therefore clinically important benefit or harm cannot be excluded.

AUTHORS' CONCLUSIONS

All six RCTs were too small to exclude clinically important benefit or harm from the assessed interventions. The certainty of the evidence was low or very low for all interventions and outcomes.

Biological Drugs in Guillain-Barré Syndrome: An Update

Background:

Guillain-Barré Syndrome (GBS) is currently considered the most common global cause of acute flaccid paralysis. Currently, standard therapy for Guillain-Barré Syndrome includes intravenous immunoglobulin or plasma exchange. Despite medical advances regarding these treatments, many treated patients do not reach full recovery. Therefore several biological agents have attracted the attentions from researchers during the last decades, and various studies have investigated their role in Guillain-Barré Syndrome.

Objective:

The present study aims to address emerging biological approaches to GBS while considering their efficiency and safety in treating the disease.

Materials and Methods:

An extensive electronic literature search was conducted by two researchers from April 2016 to July 2016. Original articles, clinical trials, systematic reviews (with or without meta-analysis) and case reports were selected. Titles and abstracts of papers were screened by reviewers to determine whether they met the eligibility criteria, and full texts of the selected articles were retrieved.

Results:

Herein authors focused on the literature data concerning emerging biological therapeutic agents, namely anti-C5 monoclonal antibody (Eculizumab), anti-C1q monoclonal antibody, anti-T cell monoclonal antibody, anti-CD2 monoclonal antibody, anti L-selectin monoclonal antibody, anti-CD20 monoclonal antibody (Rituximab), anti-CD52 monoclonal antibody (Alemtuzumab) and cytokine targets. By far, none of these agents have been approved for the treatment of GBS by FDA.

Conclusion:

Literature findings represented in current review herald promising results for using these biological targets. Current review represents a summary of what is already in regards and what progress is required to improve the immunotherapeutic approach of treating GBS via future studies.

Pharmacological treatment other than corticosteroids, intravenous immunoglobulin and plasma exchange for Guillain-Barré syndrome

BACKGROUND

Plasma exchange and intravenous immunoglobulin, but not corticosteroids, are beneficial in Guillain-Barré syndrome (GBS). The efficacy of other pharmacological agents is unknown. This review was first published in 2011 and updated in 2013 and 2016.

OBJECTIVES

To assess the effects of pharmacological agents other than plasma exchange, intravenous immunoglobulin and corticosteroids for GBS.

SEARCH METHODS

On 18 January 2016, we searched the Cochrane Neuromuscular Specialised Register, Cochrane Central Register of Controlled Trials, MEDLINE, and Embase for treatments for GBS. We also searched clinical trials registries.

SELECTION CRITERIA

We included all randomised controlled trials (RCTs) or quasi-RCTs of acute GBS (within four weeks from onset) of all types and degrees of severity, and in individuals of all ages. We discarded trials that investigated only corticosteroids, intravenous immunoglobulin or plasma exchange. We included other pharmacological treatments or combinations of treatments compared with no treatment, placebo or another treatment. We also identified a number of non-randomised studies during the search, the results of which we considered in the Discussion.

DATA COLLECTION AND ANALYSIS

We followed standard Cochrane methodology.

MAIN RESULTS

We identified no new trials during this update of the review. In previous versions of this review we identified only very low quality evidence for four different interventions published in four studies. Each study had a high risk of bias in at least one respect. One RCT with 19 participants comparing interferon beta-1a and placebo showed no clinically important difference in any outcome between groups. Another with 10 participants comparing brain-derived neurotrophic factor and placebo showed no clinically important difference in any outcome between groups. A third with 37 participants comparing cerebrospinal fluid filtration and plasma exchange also showed no clinically important difference in any outcome between groups. In a fourth with 43 participants, the risk ratio for an improvement by one or more disability grade after eight weeks was greater with the Chinese herbal medicine tripterygium polyglycoside than with corticosteroids (risk ratio 1.47; 95% confidence interval 1.02 to 2.11); other outcomes in this trial showed no difference. Serious adverse events were uncommon with each of these treatments and in the control groups.

AUTHORS' CONCLUSIONS

The quality of the evidence was very low. Three small RCTs, comparing interferon beta-1a or brain-derived neurotrophic factor with placebo, and cerebrospinal fluid filtration with plasma exchange, showed no significant benefit or harm for any of the interventions. A fourth small trial showed that the Chinese herbal medicine, tripterygium polyglycoside, hastened recovery in people with GBS to a greater extent than corticosteroids, but this result needs confirmation. We were unable to draw any useful conclusions from the few observational studies we identified.

Pharmacological treatment other than corticosteroids, intravenous immunoglobulin and plasma exchange for Guillain-Barré syndrome

BACKGROUND

Plasma exchange and intravenous immunoglobulin, but not corticosteroids, are beneficial in Guillain-Barré syndrome (GBS). The efficacy of other pharmacological agents is unknown. This review was first published in 2011 and this update in 2013. 

OBJECTIVES

To review systematically the evidence from randomised controlled trials (RCTs) for pharmacological agents other than plasma exchange, intravenous immunoglobulin and corticosteroids.

SEARCH METHODS

On 28 August 2012, we searched the Cochrane Neuromuscular Disease Group Specialized Register CENTRAL (2012, Issue 8 in The Cochrane Library), MEDLINE (January 1966 to August 2012) and EMBASE (January 1980 to August 2012) for treatments for GBS. We considered evidence from non-randomised studies in the Discussion.

SELECTION CRITERIA

We included all randomised or quasi-RCTs of acute (within four weeks from onset) GBS of all types, ages and degrees of severity. We discarded trials which only tested corticosteroids, intravenous immunoglobulin or plasma exchange. We included other pharmacological treatments or combinations of treatments compared with no treatment, placebo treatment or another treatment.

DATA COLLECTION AND ANALYSIS

Change in disability after four weeks was the primary outcome. Two authors checked references and extracted data independently. One author entered and another checked data in Review Manager (RevMan). We assessed risk of bias according to the Cochrane Handbook for Systematic Reviews of Interventions. We calculated mean differences and risk ratios with their 95% confidence intervals. We assessed strength of evidence with GradePro software.

MAIN RESULTS

Only very low quality evidence was found for four different interventions. This update of the review found no new trials. One RCT with 13 participants showed no significant difference in any outcome between interferon beta-1a and placebo. Another with 10 participants showed no significant difference in any outcome between brain-derived neurotrophic factor and placebo. A third with 37 participants showed no significant difference in any outcome between cerebrospinal fluid filtration and plasma exchange. In a fourth with 20 participants, the risk ratio of improving by one or more disability grades after eight weeks was significantly greater with the Chinese herbal medicine tripterygium polyglycoside than with corticosteroids (risk ratio 1.47; 95% confidence interval 1.02 to 2.11). Serious adverse events were uncommon with each of these treatments and not significantly commoner in the treated than the control groups.

AUTHORS' CONCLUSIONS

The quality of the evidence was very low. Three small RCTs, of interferon beta-1a, brain-derived neurotrophic factor and cerebrospinal fluid filtration, showed no significant benefit or harm. A fourth small trial showed that the Chinese herbal medicine tripterygium polyglycoside hastened recovery significantly more than corticosteroids but this result needs confirmation. It was not possible to draw useful conclusions from the few observational studies.

Pharmacological treatment other than corticosteroids, intravenous immunoglobulin and plasma exchange for Guillain Barré syndrome

BACKGROUND

Plasma exchange and intravenous immunoglobulin, but not corticosteroids, are beneficial in Guillain-Barré syndrome (GBS). The efficacy of other pharmacological agents is unknown.  

OBJECTIVES

To review systematically the evidence from randomised controlled trials for pharmacological agents other than plasma exchange, intravenous immunoglobulin and corticosteroids.

SEARCH STRATEGY

We searched the Cochrane Neuromuscular Disease Group Specialized Register (5 July 2010), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2010, Issue 2), MEDLINE (January 1966 to June 2010) and EMBASE (January 1980 to June 2010) for treatments for GBS. We considered evidence from non-randomised studies in the Discussion.

SELECTION CRITERIA

We included all randomised or quasi-randomised controlled trials of acute (within four weeks from onset) GBS of all types, ages and degrees of severity. We discarded trials which only tested corticosteroids, intravenous immunoglobulin or plasma exchange. We included other pharmacological treatments or combinations of treatments compared with no treatment, placebo treatment or another treatment.

DATA COLLECTION AND ANALYSIS

Change in disability after four weeks was the primary outcome. Two authors checked references and extracted data independently. One author entered and another checked data in Review Manager (RevMan). We assessed risk of bias according to the Cochrane Handbook for Systematic Reviews of Interventions. We calculated mean differences and risk ratios with their 95% confidence intervals. We assessed strength of evidence with GradePro software.

MAIN RESULTS

Only very low quality evidence was found for four different interventions. One randomised controlled trial with 13 participants showed no significant difference in any outcome between interferon beta-1a and placebo. Another with 10 participants showed no significant difference in any outcome between brain-derived neurotrophic factor and placebo. A third with 37 participants showed no significant difference in any outcome between cerebrospinal fluid filtration and plasma exchange. In a fourth with 20 participants, the risk ratio of improving by one or more disability grades after eight weeks was significantly greater with the Chinese herbal medicine tripterygium polyglycoside than with corticosteroids (risk ratio 1.47; 95% confidence interval 1.02 to 2.11).

AUTHORS' CONCLUSIONS

The quality of the evidence was very low. Three small randomised controlled trials, of interferon beta-1a, brain-derived neurotrophic factor and cerebrospinal fluid filtration, showed no significant benefit or harm. A fourth small trial showed that the Chinese herbal medicine tripterygium polyglycoside hastened recovery significantly more than corticosteroids but this result needs confirmation. It was not possible to draw useful conclusions from the few observational studies.

Current Therapeutic Options in Severe Guillain-Barre?? Syndrome

The classical form of Guillain-Barré syndrome (GBS) refers to an acute monophasic demyelinating motor and sensory polyneuropathy characterized by symmetric ascending flaccid weakness, along with sensory impairment and, less commonly, autonomic perturbations. Pure motor axonal forms, axonal motor, and sensory forms, as well as pure autonomic forms, have also been identified. A complex immune-mediated process leads to segmental demyelination accompanied with axonal involvement in protracted cases. Establishing strategies of immunomodulation may therefore halt and even reverse the harmful autoimmune insult to peripheral nerves. The present article reviews the current immunomodulatory options in severe GBS. A recent Cochrane meta-analysis of 6 randomized studies showed no significant improvement using corticosteroids, including either oral or intravenous methylprednisolone. Combined methylprednisolone and immunoglobulins shortened the time lapse to regain independent walking. Plasmapheresis (PE) was the first effectively proven method of immunomodulation, followed by intravenous immunoglobulins (IVIG). Both methods are comparable in their beneficial effect and were used either separately or in combination, but PE was more frequently associated with severe adverse effects requiring cessation of therapy, including a bleeding diathesis. In addition, PE is feasible only in major referral centers requiring the appropriate equipment and trained personnel. In addition, younger children may be at risk for bleeding after insertion of wide catheters. Therefore, in cases of severe GBS, IVIG is recommended as the first-line drug using a total empiric dose of 2 g/kg administered over 2 consecutive days, especially in children proven highly effective with negligible adverse effects. In protracted cases, the addition of intravenous corticosteroids to IVIG should be considered, which may shorten the duration to regain independent walking. If such therapy fails, PE should be applied using centrifugal blood separators with 5% albumin as the substitute solution.

Novel therapeutic approaches to Guillain-Barré syndrome

Guillain-Barré syndrome is an autoimmune disease which occurs throughout the world. Whilst the majority of patients can expect a reasonable recovery, about 10% die and 10% are left disabled with current therapy. The standard treatment is a five day course of iv. immunoglobulin, given at a dose of 0.4 g/kg/day, with plasma exchange as an equally efficacious alternative. Steroids are ineffective in Guillain-Barré syndrome. All new potential therapeutic agents need to be tested in addition to the standard agents available. Future potential therapies are suggested by the study of the animal model experimental autoimmune neuritis in the Lewis rat. Whilst in theory it is possible to target the different stages of the immune response, in practice not all of the steps at which experimental autoimmune neuritis can be prevented will be translatable to human Guillain-Barré syndrome. This is because Guillain-Barré syndrome probably presents after the immune reaction has been ongoing for some time and therefore early aspects of the immune response cannot be prevented. Many of the possible measures would have widespread immunosuppressive effects which would be unacceptable to patients. Interfering with the immune response by attempting to block antigen binding or inducing tolerance may not be practical, owing to the possibility of exacerbating disease. Once we have a more thorough understanding of the pathogenesis of Guillain-Barré syndrome, then immune-specific therapy for Guillain-Barré syndrome may become a possibility, rather than general immunosuppressive measures. Trials of beta-interferon and of a combination of steroid and i.v. immunoglobulin are underway. A trial of a second course of i.v. immunoglobulin is planned.

T helper type 2 like cytokine responses to peptides from P0 and P2 myelin proteins during the recovery phase of Guillain-Barré syndrome

T-lymphocytes are probably involved in the pathogenesis of Guillain-Barré syndrome (GBS). T-helper-1 (Th1) cytokines activate macrophages and induce a delayed type hypersensitivity (DTH) inflammatory response, consistent with the morphology of the demyelination in GBS. Th2 cytokines encourage antibody production and downregulate Th1 responses. To study the Th1/Th2 cytokines in relation to the clinical course of GBS an ELISPOT method for determination of single cells secreting interferon-gamma, IFN-gamma (Th1) or interleukin-4, IL-4 (Th2) was used. We serially investigated antigen-induced cytokine secretion from circulating T-cells stimulated with human peptides from the P0 and P2 proteins in seven patients and compared to results from seven serially investigated healthy controls. Most patients (five of seven) showed IL-4 responses during the plateau- or recovery-phase as compared to controls. One patient with a prolonged disease course, on the other hand, had an IFN-gamma dominated reactivity. We suggest that the IL-4 responses are beneficial in GBS, and may have a role in terminating the disease process in this self-limiting inflammatory disease.

Guillain-Barré syndrome in immunocompromised patients: a report of three patients and review of the literature

Both humoral and cell-mediated autoimmune mechanisms have been implicated in the pathogenesis of Guillain-Barré syndrome (GBS). Therefore, its occurrence in severely immunocompromised patients is not expected. We identified 3 severely immunocompromised patients who developed GBS. Two of the 3 patients had acquired immunodeficiency syndrome with CD4 counts of 5 and 4 cells/mm3, respectively. One post-cardiac transplant patient was taking azathioprine and cyclosporine at the time of onset of GBS. In all 3 patients, immunocompromise was induced by infectious or chemotherapeutic agents which preferentially suppress T-lymphocyte responses. All 3 had severe lymphocytopenia and incomplete recovery. We conclude that GBS can occur in patients with severe t-cell suppression. Although no conclusion regarding prognosis can be drawn from our small group of patients, their incomplete recovery is consistent with the idea that T-cells are important for recovery.

Monoclonal antibodies--immunotherapy for the critically ill

Monoclonal antibodies (mAb) have revolutionised many areas of medicine, particularly research and diagnostics. Murine, human and humanized mAb have all been developed. The most important clinical applications to date have been in the fields of transplantation and oncology. Experimental and limited clinical trials suggest mAb are emerging as a new therapeutic strategy in the critically ill. Antibodies against a variety of bacteria or their products are potentially useful in gram-positive and gram-negative shock. Anti-cytokine and anti-neutrophil adhesion molecule mAb may be effective not only in septic shock but also in other conditions associated with acute inflammation and cytokine release, e.g., acid aspiration, ischaemia/reperfusion injury (myocardial infarction, haemorrhagic shock, aortic aneurysm repair). Antibodies inhibiting neutrophil adhesion may also be efficacious in asthma, pulmonary fibrosis, meningitis and cerebral malaria. The use of these and other mAb in intensive care is an exciting prospect and future clinical studies will determine the extent of their role in the management of the critically ill.

Antigalactocerebroside antibody increases demyelination in adoptive transfer experimental allergic neuritis

There is suggestive but inconclusive evidence for a contribution of T cells and antimyelin antibodies to the pathogenesis of the Guillain-Barré polyneuropathy. We have studied the potential synergism of cellular and humoral immunity in the adoptive transfer model of EAN. EAN was induced in Lewis rats by injecting varying doses of P2 peptide (SP26)-sensitized T lymphocytes. Disease severity was dose-dependent. The addition of intravenous GC-AB to a subclinical dose of SP26-sensitized T cells resulted in overt clinical disease and markedly enhanced demyelination. Intravenous injection of antibody alone had no effect. We conclude that activated neuritogenic T cells, while entering into peripheral nerves, alter the blood-nerve barrier, which gives circulating demyelinating antibodies access to the endoneurium. The observations support the concept of a synergistic role of T-cell autoimmunity and humoral responses in the inflammatory demyelination of Lewis rat EAN.