The role of immunotherapy in Guillain-Barré syndrome: understanding the mechanism of action

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.

Modified Zipper Method, a Promising Treatment Option in Severe Pediatric Immune-Mediated Neurologic Disorders

OBJECTIVE

To introduce and evaluate a modified version of the "zipper method"-a treatment strategy alternating intravenous immunoglobulin (IVIG) and plasma exchange (PLEX) first reported for 9 pediatric cases of Guillain-Barré syndrome in 2018-for treatment of severe immune-mediated neurologic disorders in children.

METHODS

The modified zipper method comprised longer intervals between PLEX-IVIG cycles (48 hours instead of 24 hours), more cycles (7-10 instead of 5), a consistent plasma volume exchange (instead of the original multistep approach), and variable infusion times for IVIGs (4-8 hours). The modified zipper method was applied as an individual treatment approach once standard therapy failed. The follow-up ranged from 6 months to 2 years. Cases were analyzed retrospectively. Disease severity was mainly quantified by the Guillain-Barré syndrome disability score.

RESULTS

Four children (9-15 years) with (1) Miller-Fisher syndrome, (2) Bickerstaff brainstem encephalitis, (3) common Guillain-Barré syndrome, and (4) severe acute disseminated encephalomyelitis were treated by the modified zipper method. Results for duration of mechanical ventilation (median of 12 days, interquartile range [IQR] 8-16), hospital stay (median of 23 days, IQR 22-24), and time to unaided walking (median of 22 days, IQR 21-37) outperformed previous studies with IVIG/PLEX alone or IVIG + PLEX combinations unlike the zipper method.

CONCLUSION

The modified zipper method is associated with a low mortality, a short mechanical ventilation time, a short hospital stay, and an excellent outcome in children with severe Guillain-Barré syndrome or acute disseminated encephalomyelitis. Our regimen is streamlined for applicability. Results emphasize its robust effectiveness as an option for therapy escalation in severe neuroimmunologic diseases. Now, multicenter trials are needed to evaluate this novel treatment strategy.

Efficacy of intravenous immunoglobulin in autoimmune neurological diseases. Literature systematic review and meta-analysis

BACKGROUND

Corticosteroids are the first-line treatment for several common autoimmune neurological diseases. Other therapeutic approaches, including intravenous immunoglobulin (IVIg) and plasmapheresis, have shown mixed results in patient improvement.

OBJECTIVE

To compare the efficacy of IVIg administration with that of corticosteroids, plasmapheresis, and placebo in autoimmune neurological diseases like Guillain-Barré syndrome, myasthenia gravis, chronic inflammatory demyelinating polyneuropathy, optic neuritis, and multiple sclerosis.

METHODS

A systematic review was performed on the databases PubMed, MEDLINE, Embase, and Cochrane. Controlled, randomized studies comparing the efficacy of IVIg with placebo, plasmapheresis, and/or glucocorticoid administration were selected. Only studies reporting the number of patients who improved after treatment were included, irrespective of language or publication year. In total, 23 reports were included in the meta-analysis study.

RESULTS

Our meta-analysis showed a beneficial effect of IVIg administration on patient improvement over placebo (OR = 2.79, CI [95%] = 1.40-5.55, P = 0.01). Meanwhile, IVIg administration showed virtually identical effects to plasmapheresis (OR = 0.83, CI [95%] = 0.45-1.55, P < 0.01). Finally, no significant differences were found in the efficacy of IVIg and glucocorticoid administration (OR = 0.98, Cl [95%] = 0.58-1.68, P = 0.13).

CONCLUSION

IVIg can be regarded as a viable therapeutic approach, either as a first- or second-line therapy, and as an adjuvant therapy for autoimmune neurological diseases.

Hyperbaric oxygen therapy in a patient with Guillain-Barré syndrome receiving mechanical ventilation

The mortality rate of patients with Guillain-Barré syndrome (GBS) who develop respiratory muscle paralysis and need mechanical ventilation is increased. Though an unestablished indication, hyperbaric oxygen treatment (HBOT) has been used to treat patients with mild GBS who do not have respiratory muscle paralysis. The use of HBOT in severe cases has not been reported. We present a patient with severe GBS who received HBOT while ventilated in a multiplace hyperbaric chamber. Three courses of HBOT (one session per day, 10 sessions per course) were administered with a 2-day rest period between each course. The HBOT protocol was 40 minutes at 220 kPa with 25 minutes of compression and decompression. Following weeks of gradual deterioration, motor function improved after the first HBOT session. After eight HBOT sessions, the patient was successfully discontinued from mechanical ventilation and after 10 sessions the patient's muscle strength was significantly improved. After 30 HBOT sessions, the patient had normal breathing and speech, and did not cough when eating. Upper limb muscle strength was graded as 4 on the Medical Research Council (MRC) scale, lower limb muscle strength was graded as MRC 3. The patient was successfully discharged. Mechanically ventilated GBS patients may benefit from HBOT but studies are required to separate spontaneous recovery rates from treatment benefit.

The effectiveness and safety of acupuncture therapy for Guillain-Barré syndrome: A systematic review and meta-analysis protocol

BACKGROUND

Guillain-Barré syndrome (GBS) is the most common acute paralytic neuropathy. Many clinical trials indicate acupuncture provides a good effect as a complementary therapy of Western medicine for GBS. The objective of this systematic review protocol is to provide the evidence to evaluate the effectiveness and safety of acupuncture on the treatment of GBS.

METHODS

We will search relevant randomized controlled trials investigating the effect of acupuncture for GBS in following databases from start to October 2019: PubMed, Embase, the Cochrane Library, CINAHL Complete, National Digital Science Library, China National Knowledge Infrastructure, and Wanfang Database without language restriction. For articles that meet our inclusion criteria, 2 researchers will extract the data information independently, and assess the risk of bias and trial quality by the Cochrane collaboration's tool. All data will be analyzed by RevMan V.5.3.3 statistical software.

RESULTS

According to the Barthel index of Activities of Daily Living (ADL) and the Medical Research Council (MRC) muscle scale, the efficacy and safety of acupuncture for GBS will be determined in this study.

CONCLUSION

This systemic review will provide high quality evidence to judging whether acupuncture provides benefits to treat GBS.Prospero registration number: CRD42019158710.

Severe Guillain-Barré syndrome associated with chronic active hepatitis C and mixed cryoglobulinemia: a case report

Background

We describe a case of severe Guillain-Barre syndrome (GBS) associated with chronic active hepatitis C and mixed cryoglobulinemia (MC). To our knowledge, this association between GBS and hepatitis C virus (HCV) infection has been rarely reported.

Case presentation

A 56-year-old man developed symmetrical muscle weakness in all extremities, areflexia and sensorial disorder followed by acute respiratory failure associated with chronic active hepatitis C, which was confirmed by the presence of anti-HCV antibodies in the serum and persistence of HCV RNA viral load for more than 6 months. Chronic hepatitis C was further complicated by type 3 MC. Electromyography showed peripheral nerve injury (mainly in axon). A severe acute motor sensory axonal neuropathy (AMSAN) was diagnosed. After treatment with intravenous immunoglobulin and plasma exchange followed by antiviral therapy by direct-acting antiviral agent, patient showed progressive recovery and was transferred 3 months after his first admission to a rehabilitation center.

Conclusions

Our case reported a severe GBS associated with HCV infection and MC. EMG classified for the first time the subtype of GBS (severe AMSAN) correlated with severe clinical form. HCV infection should be screened in high-risk patients to prevent silent progression of the chronic hepatitis C and its potentially severe extra-hepatic manifestations.

A Novel Treatment Strategy for Severe Guillain-Barré Syndrome: Zipper Method

OBJECTIVE

Intravenous immunoglobulin and plasma exchange are proven treatments for Guillain-Barré syndrome. Despite these treatments, the prognosis for severe Guillain-Barré syndrome is still not satisfactory. This article seeks for a logical timing for plasma exchange-intravenous immunoglobulin synergy, which may improve outcome in severe Guillain-Barré syndrome requiring mechanical ventilation.

STUDY DESIGN

This study is an open-label study. Nine pediatric severe Guillain-Barré syndrome patients requiring mechanical ventilation were treated with novel treatment strategy named as "zipper method." In this method, following diagnosis of Guillain-Barré syndrome, plasma exchange was started immediately. In the first session of plasma exchange, one and a half volume of patients' plasma was removed by using 5% albumin as replacement solution. At the end of the plasma exchange session, 0.4 g/kg intravenous immunoglobulin infusion was started immediately. Second plasma exchange session was applied with one volume change after 24 hours from the end of the intravenous immunoglobulin infusion. Each plasma exchange session was followed by intravenous immunoglobulin infusions. This plasma exchange-intravenous immunoglobulin cycle was repeated for 5 times.

RESULTS

Among the 9 patients, the mean mechanical ventilation duration was 7 (5-14) days and the mean hospital stay was 18 (10-30) days. Medical Research Council sum score was increased in all patients, especially after the third session. All patients survived and all patients were able to walk unaided on the 28th day of admission.

CONCLUSION

The zipper method as a novel treatment modality seems to reduce mortality, speed up weaning from mechanical ventilation, and shorten hospital stay, with excellent outcome in severe Guillain-Barré syndrome patients, who require intensive care. This technique stands as a promising immunomodulation strategy for various scenarios.

Decitabine induces regulatory T cells, inhibits the production of IFN-gamma and IL-17 and exerts preventive and therapeutic efficacy in rodent experimental autoimmune neuritis

Guillain-Barré syndrome (GBS) is an immune-mediated acute disorder of the peripheral nervous system. Despite treatment, there is an associated mortality and severe disability in 9 to 17% of the cases. Decitabine (DAC) is a hypomethylating drug used in myelodisplastic syndrome, that has been shown to exert immunomodulatory effects. We have evaluated the effects of DAC in two rodent models of GBS, the Experimental Allergic Neuritis (EAN). Both prophylactic and therapeutic treatment with DAC ameliorated the clinical course of EAN, increasing the numbers of thymic regulatory T cells and reducing the production of proinflammmatory cytokines. Our data suggest the possible use of decitabine for the treatment of GBS.

Is a second cycle of immunoglobulin justified in axonal forms of Guillain-Barré syndrome?

Objective In certain situations, severe forms of Guillain-Barré syndrome (GBS) show no response or continue to deteriorate after intravenous immunoglobulin (IVIg) infusion. It is unclear what the best treatment option would be in these circumstances.Method This is a case report on patients with severe axonal GBS in whom a second cycle of IVIg was used.Results Three patients on mechanical ventilation who presented axonal variants of GBS, with autonomic dysfunction, bulbar impairment and Erasmus score > 6, showed no improvement after IVIg infusion of 400 mg/kg/d for 5 days. After 6 weeks, we started a second cycle of IVIg using the same doses and regimen as in the previous one. On average, 5 days after the second infusion, all the patients were weaned off mechanical ventilation and showed resolution of their blood pressure and heart rate fluctuations.Conclusions A second cycle of IVIg may be an option for treating severe forms of GBS.

Relationship Between Cerebrospinal Fluid Protein Levels and Electrophysiologic Abnormalities in Guillain-Barré Syndrome

OBJECTIVES

The cerebrospinal fluid (CSF) protein level is known to be elevated in patients with Guillain-Barré syndrome (GBS). This report correlates the degree of CSF protein elevation with the number of electrophysiologic abnormalities on nerve conduction study (NCS).

METHODS

We reviewed 38 patients admitted to our institution with a diagnosis of GBS and had both a measured CSF protein level and a NCS within 24 hours of each other.

RESULTS

CSF protein level correlates with the number of NCS demyelination criteria, as described by Cornblath, in patients with GBS.

CONCLUSIONS

This retrospective study is the first to demonstrate a relationship between the CSF protein level and the electrophysiologic abnormalities that accompany GBS.

Intravenous immunoglobulin in critically ill adults: When and what is the evidence?

Intravenous immunoglobulin (IVIg) use is growing dramatically internationally due to the increasing numbers of acute and chronic conditions that may benefit from IVIg. Patients with conditions that may benefit from IVIg might require intensive care unit (ICU) admission, supporting the need to review IVIg use in the critical care setting. The most common clinical indications for IVIg in adults that may require ICU admission and are commonly supported under clinical practice guidelines are Guillain-Barré syndrome, myasthenia gravis and Lambert-Eaton myasthenic syndrome, inflammatory myopathies, and primary or secondary immunodeficiency diseases complicated by severe bacterial sepsis. Other emerging indications include necrotizing fasciitis, toxic epidermal necrolysis/Stevens-Johnson syndrome, and toxic shock syndrome. The evidence for IVIg use in sepsis and septic shock remains controversial and insufficient to recommend its routine use. Intravenous immunoglobulin is expensive and also carries risks of adverse effects, including common and benign infusion-related reactions, as well as relatively rare and more serious problems, such as thromboembolic events, renal failure, and aseptic meningitis. In this article, we review the literature on conditions requiring ICU admission and IVIg, and we classify them as supported, emerging, or unsupported indications based on the available evidence and guidelines for clinical use of IVIg.

Beneficial effect of a multimerized immunoglobulin Fc in an animal model of inflammatory neuropathy (experimental autoimmune neuritis)

Intravenous immunoglobulin (IVIg) is one of the first-line therapies for inflammatory neuropathies. Clinical use of IVIg for these disorders is limited by expense and availability. Here, we investigated a synthetic product alternative to IVIg. The aim of this study was to test the therapeutic efficacy of a novel recombinant polyvalent murine IgG2a Fc compound (stradomer™) in experimental autoimmune neuritis (EAN). Seventy-four Lewis rats were immunized with myelin, randomized into three groups, and were treated with albumin, IVIg, or stradomer at 1% of IVIg dose. Rats were assessed clinically, electrophysiologically, and histologically. The clinical disease severity was evaluated by clinical grading and weight changes. The electrophysiological studies recorded motor conduction velocity (MCV), amplitudes, and latencies of the evoked compound muscle action potential (CMAP) and spinal somatosensory evoked potential. The treatment efficacy of the IVIg and stradomer groups was compared to the albumin (control) group. We demonstrate that stradomer has a similar therapeutic efficacy to human IVIg in EAN. Rats receiving stradomer or IVIg showed significantly lower clinical scores and less prominent weight loss compared with controls. A statistically significant improvement in both MCV and the amplitudes of distal and proximal evoked CMAP was observed in the stradomer and IVIg groups. Finally, treatment with both IVIg and stradomer resulted in statistically less inflammation and demyelinating changes in the sciatic nerve as evidenced by lower histological grade. These results reveal the potential of using fully recombinant multimerized immunoglobulin Fc instead of IVIg for treating inflammatory neuropathies.

Structural heterogeneity of terminal glycans in Campylobacter jejuni lipooligosaccharides

Lipooligosaccharides of the gastrointestinal pathogen Campylobacter jejuni are regarded as a major virulence factor and are implicated in the production of cross-reactive antibodies against host gangliosides, which leads to the development of autoimmune neuropathies such as Guillain-Barré and Fisher Syndromes. C. jejuni strains are known to produce diverse LOS structures encoded by more than 19 types of LOS biosynthesis clusters. This study demonstrates that the final C. jejuni LOS structure cannot always be predicted from the genetic composition of the LOS biosynthesis cluster, as determined by novel lectin array analysis of the terminal LOS glycans. The differences were shown to be partially facilitated by the differential on/off status of three genes wlaN, cst and cj1144-45. The on/off status of these genes was also analysed in C. jejuni strains grown in vitro and in vivo, isolated directly from the host animal without passaging, using immunoseparation. Importantly, C. jejuni strains 331, 421 and 520 encoding cluster type C were shown to produce different LOS, mimicking asialo GM₁, asialo GM₂ and a heterogeneous mix of gangliosides and other glycoconjugates respectively. In addition, individual C. jejuni colonies were shown to consistently produce heterogeneous LOS structures, irrespective of the cluster type and the status of phase variable genes. Furthermore we describe C. jejuni strains (351 and 375) with LOS clusters that do not match any of the previously described LOS clusters, yet are able to produce LOS with asialo GM₂-like mimicries. The LOS biosynthesis clusters of these strains are likely to contain genes that code for LOS biosynthesis machinery previously not identified, yet capable of synthesising LOS mimicking gangliosides.