Increased circulating T cell reactivity to GM1 ganglioside in patients with Guillain–Barré syndrome

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

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

Sex differences in Guillain Barré syndrome, chronic inflammatory demyelinating polyradiculoneuropathy and experimental autoimmune neuritis

Guillain Barré syndrome (GBS) and its variants, and chronic inflammatory demyelinating polyradiculoneuropathy (CIDP and its variants, are regarded as immune mediated neuropathies. Unlike in many autoimmune disorders, GBS and CIDP are more common in males than females. Sex is not a clear predictor of outcome. Experimental autoimmune neuritis (EAN) is an animal model of these diseases, but there are no studies of the effects of sex in EAN. The pathogenesis of GBS and CIDP involves immune response to non-protein antigens, antigen presentation through non-conventional T cells and, in CIDP with nodopathy, IgG4 antibody responses to antigens. There are some reported sex differences in some of these elements of the immune system and we speculate that these sex differences could contribute to the male predominance of these diseases, and suggest that sex differences in peripheral nerves is a topic worthy of further study.

SARS-CoV-2 and Guillain-Barré Syndrome: Lessons from Viral Infections

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is responsible for the COVID-19 pandemic. COVID-19 has a broad clinical spectrum from asymptomatic patients to multiorgan dysfunction and septic shock. Most of the common symptoms of COVID-19 are classified as respiratory disorders, but some reports show neurological involvements. During the COVID-19 pandemic, a case series of neurological complications, such as Guillain-Barré syndrome (GBS), were reported. GBS is a neuroimmune disorder with acute inflammatory radicular polyneuropathy in different parts of the peripheral nerve. Some studies have reported GBS as an inflammatory neuropathy related to various viral infections, such as cytomegalovirus (CMV), Epstein-Barr Virus (EBV), herpes simplex virus (HSV), human immunodeficiency virus (HIV), influenza, and Zika virus. There are some immunomodulation approaches for the management of GBS. Studies have evaluated the effects of the various therapeutic approaches, including intravenous immunoglobulin (IVIG), plasma exchange (PE), complement inhibitors, and corticosteroids to regulate overactivation of immune responses during GBS in experimental and clinical studies. In this regard, the possible association between GBS and SARS-CoV-2 infection during the outbreak of the current pandemic and also the mentioned therapeutic approaches were reviewed.

Genetic polymorphisms in Guillain-Barré Syndrome: A field synopsis and systematic meta-analysis

OBJECTIVE

Guillain-Barré Syndrome (GBS) is considered to be a complex immune-mediated neuropathy. In the past few years, numerous studies were performed to detect the association between genetic polymorphisms and GBS risk. However, the findings of these studies were controversial. Thus, we conducted this field synopsis and systematic meta-analysis for further evaluating the possible associations between all available genetic polymorphisms and GBS susceptibility.

METHODS

Relevant studies focusing on the association between all genetic polymorphisms and GBS risk were obtained by a comprehensive literature search. The pooled odds ratios (ORs) as well as 95% confidence intervals (CIs) were used for assessing the strength of association. Subgroup analyses stratified by ethnicity and GBS subtype were further performed. Moreover, sensitive analysis and publication bias were conducted for evaluating the reliability of the results.

RESULTS

Among the initial identified 333 articles, 41 articles reporting on 220 genetic polymorphisms were extracted for conducting this systematic review. Then, we performed 95 primary and 94 subgroup meta-analyses for 59 variants with at least three independent studies available. The results showed significant association between four variants (FcγR IIA rs1801274, TNF-α rs1800629, HLA DRB1*0401 and HLA DRB1*1301) and GBS susceptibility. In the subgroup analysis, three (TNF-α rs1800629, TNF-α rs1800630 and TLR4 rs4986790) and two (FcγR IIA rs1801274, HLA DRB1*14) variants showed association with increased GBS risk in Asian and Caucasian population, respectively. Also, TNF-α rs1800629 was significant associated with AMAN subtypes of GBS. Furthermore, sensitivity analysis, funnel plots and Egger's test displayed robust results, except for FcγR IIA rs1801274. Additionally, for 161 variants with less than three studies, 17 genetic variants have been found to be significantly related with GBS risk in our systematic review.

INTERPRETATION

In our study, we assessed the association between all available genetic polymorphisms and GBS susceptibility. We hope our findings would be helpful for identifying novel genetic biomarkers and potential therapeutic targets for GBS.

The frequencies of Killer immunoglobulin-like receptors and their HLA ligands in chronic inflammatory demyelinating polyradiculoneuropathy are similar to those in Guillian Barre syndrome but differ from those of controls, suggesting a role for NK cells in pathogenesis

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is an acquired inflammatory neuropathy, which has similar clinical and pathological features to Guillain-Barré Syndrome (GBS), but differs in time course. We investigated the frequency of genes encoding Killer immunoglobulin-like receptors and their HLA ligands in subjects with CIDP, in subjects with GBS and in healthy controls. There were no differences in KIR gene frequency among the 3 groups. The gene frequencies for HLA-B Bw4-I were significantly greater in CIDP than HC, but did not differ from GBS. The frequency of the combination of 3DL1/HLA-B Bw4I was greater in CIDP than HC, but did not differ from that of GBS. These data raise the possibility of NK cell function being an important factor in the pathogenesis of CIDP.

Autoimmune diseases of the peripheral nervous system

Autoimmune-mediated diseases targeting the peripheral nerve represent a group of disorders often associated with high clinical disability. At present, therapeutic options are limited. The application of innovative and cutting-edge technologies to the study of immune-mediated disorders of the peripheral nervous system (PNS) have generated a better understanding of underlying principles of the organization of the immune network present in the peripheral nerve and its dialogue with the systemic immune system. These insights may foster the development of specific and highly effective therapies for autoimmune diseases of the peripheral nerve. Of great interest in this context is the application of monoclonal antibodies, such as rituximab or alemtuzumab, which in small observational studies provided promising clinical results. But also other immunomodulatory or immunosuppressive drugs used in other indications currently find their way to PNS autoimmunity. Clearly, prospective controlled clinical trials are warranted before making firm conclusions on the feasibility of these innovative therapeutic approaches for treating immune-mediated disease of the peripheral nerve.

The role of cytokines in Guillain-Barré syndrome

Cytokines play an important role in the pathogenesis of autoimmune diseases including Guillain-Barré syndrome (GBS) and its animal model experimental autoimmune neuritis (EAN). In this article, we reviewed the current knowledge of the role of cytokines such as TNF-α, IFN-γ, IL-1β, IL-6, IL-12, IL-18, IL-23, IL-17, IL-10, IL-4 and chemokines in GBS and EAN as unraveled by studies both in the clinic and the laboratory. However, these studies occasionally yield conflicting results, highlighting the complex role that cytokines play in the disease process. Efforts to modulate cytokine function in GBS and other autoimmune disease have shown efficiency indicating that cytokines are important therapeutic targets.

GM1 and nerve growth factor modulate mitochondrial membrane potential and neurofilament light mRNA expression in cultured dorsal root ganglion and spinal cord neurons during excitotoxic glutamate exposure

Monosialoganglioside GM1 is a known neurotrophic factor. Nerve growth factor (NGF), a member of the neurotrophin family, is important for the survival, differentiation and maturation of neurons. The aim of this study was to test whether administration of GM1 and NGF can ameliorate glutamate (Glu) neurotoxicity in primary cultured embryonic rat dorsal root ganglia (DRG) and spinal cord neurons, and to investigate the mechanism underlying any effect. DRG and spinal cord neurons were exposed to the following treatments: Glu (2 mmol/L); Glu (2 mmol/L) plus GM1 (10mg/mL); Glu (2 mmol/l) plus NGF (10 ng/mL); Glu (2 mmol/L) plus GM1 (5mg/mL) and NGF (5 ng/mL). Cell viability was assessed using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, ultrastructural alterations were examined using inverse phase contrast microscopy and electron microscopy, mitochondrial membrane potential was measured using rhodamine 123 labeling and flow cytometry, and neurofilament light (NF-L) mRNA expression was detected by reverse transcription-polymerase chain reaction. It was found that GM1 and NGF can increase the viability of neurons incubated with Glu, which, after GM1 and NGF treatment, were almost morphologically normal. The mitochondrial membrane potential of neurons was lowest for neurons treated with Glu alone, and that for neurons treated with Glu plus GM1 and NGF was higher than that for treatment with GM1 or NGF alone. The mRNA of NF-L was expressed at the highest level in neurons treated with Glu plus GM1 and NGF. Our findings indicate that NGF and GM1 act synergistically to protect DRG and spinal cord neurons from Glu cytotoxicity. NGF and GM1 may function by maintaining normal mitochondrial membrane potential or by promoting NF-L mRNA expression.

T cells from patients with Guillain-Barré syndrome produce interferon-gamma in response to stimulation with the ganglioside GM1

Guillain-Barré syndrome (GBS) is an acquired demyelinating neuropathy, characterized by infiltration of peripheral nerves with macrophages and T cells. There have been reports of antibodies to glycolipids in GBS. We have previously found T cell reactivity to glycolipids in patients with the demyelinating form of GBS. This study was performed to characterize the cytokines produced by these T cells. Peripheral blood lymphocytes from patients with GBS, chronic inflammatory demyelinating polyradiculoneuropathy, healthy control patients and other neuropathies were incubated with the ganglioside GM1 and transferred to enzyme-linked immunospot plates. The average number per well of spot-forming cells (SFC) in the absence of antigen was counted. The average spontaneous SFC number was subtracted from the average SFC number in the presence of GM1, to produce a corrected SFC. There was significantly increased production of interferon-gamma but not interleukin-5 in response to stimulation with the ganglioside GM1. This could indicate that SFC have a role in pathogenesis of disease.

T Cell Response in Acute Motor Axonal Neuropathy

There is evidence that in the acute axonal motor neuropathy (AMAN) subtype of Guillain-Barré syndrome antibodies to gangliosides, produced through molecular mimicry by antecedent Campylobacter jejuni ( C. jejuni) infection, attack gangliosides expressed in human peripheral nerve axolemma, inducing a primary axonal damage. The aim of this study is to investigate whether the T cell response has a role in AMAN pathogenesis. We isolated monocytes from 4 healthy subjects and 5 AMAN patients with antecedent C. jejuni infection and antibodies to GM1 and/or GDla gangliosides. Immature dendritic cells expressing CD1 molecules cultured with autologous T cells were stimulated with 2 lipopolysaccharides (LPSs) extracted from C. jejuni strains containing GM1 and GDla-like structures and with GM1 and GDla. The T cell response to LPSs and to gangliosides was determined by measuring the release of IFN-γ and TNF-α. We observed a T cell response to both LPSs in controls and AMAN patients, whereas only AMAN patients showed T cell reactivity to gangliosides GM1 and GD1a with a tight correlation between T cell reactivity to the ganglioside and individual antibody responses to the same ganglioside. T cells responding to gangliosides were CD1c-restricted CD8 positive and CD27 negative. These findings indicate a contribution of cellular immunity in the pathogenesis of AMAN. A possible role for ganglioside-reactive T cells might be to facilitate the production of antibodies against gangliosides.

From bench to bedside--experimental rationale for immune-specific therapies in the inflamed peripheral nerve

Guillain-Barré syndrome and chronic inflammatory demyelinating polyradiculoneuropathy are autoimmune-mediated inflammatory diseases of the PNS. In recent years, substantial progress has been made towards understanding the immune mechanisms that underlie these conditions, in large part through the study of experimental models. Here, we review the available animal models that partially mimic human Guillain-Barré syndrome and chronic inflammatory demyelinating polyneuropathy, and discuss the wide range of therapeutic approaches that have been successfully established in these models of inflammatory neuropathies. Transfer of this preclinical knowledge to patients has been far less successful, and inflammatory neuropathies are still associated with significant morbidity and mortality. We will summarize successful therapeutic trials in human autoimmune neuropathies to provide a vantage point for the transfer of experimental treatment strategies to clinical practice in immune-mediated diseases of the peripheral nerve.

Antibody responses to peptides of peripheral nerve myelin proteins P0 and P2 in patients with inflammatory demyelinating neuropathy

BACKGROUND

Antibodies with reactivity to peripheral nerve myelin have previously been found in the serum, and bound to peripheral nerves of patients with Guillain-Barré syndrome (GBS) and chronic inflammatory demyelinating polyradiculoneuropathy (CIDP).

AIM

To investigate the presence of antibodies reactive to specific peptide sequences within the myelin proteins P0 and P2 in patients with GBS, in patients with CIDP, in healthy controls and in patients with other neuropathies (ON).

METHODS

Blood was obtained from 48 patients with GBS, 36 with CIDP, 48 with ON and 38 controls. ELISA was used to detect antibody responses to peptides of the human peripheral myelin proteins P0 and P2. Blood samples were collected from patients with GBS in early, peak and recovery stages of GBS to analyse antibody levels throughout the course of the disease.

RESULTS

Significantly increased total IgG levels were found in patients with GBS compared with other groups. A higher percentage of patients with GBS at the peak of disease had antibody reactivity to P2(14-25) compared with patients with CIDP and control groups. In patients with GBS and CIDP, the percentages of patients with antibody reactivity to P2(61-70), and peptides derived from P0, were comparable to the control groups. Although some individual patients with GBS had high titres of reactivity to the peptide antigens tested, most patients with GBS and CIDP had levels of antibody similar to controls.

CONCLUSION

Our data suggest that increased IgG levels and increased antibody reactivity to P2(14-25) in patients with GBS at the peak of disease may play a contributory role in the disease process in some patients with demyelinating forms of GBS.

Immune circuitry in the peripheral nervous system

PURPOSE OF REVIEW

The aim of this review is to describe the local immune circuitry in the peripheral nervous system and its dialogue with systemic immunity under pathological conditions. Specifically, interactions of the immune system with cellular and extracellular components within peripheral nerve and immune functions of tissue-resident endoneurial macrophages and Schwann cells will be discussed.

RECENT FINDINGS

New insights into the elements involved in the pathogenesis of immune-mediated disorders of the peripheral nervous system provide a better understanding of the complex interplay of these cellular and molecular components in the immunology of the peripheral nervous system.

SUMMARY

The application of innovative and cutting-edge technologies to the study of immunoinflammatory disorders of the peripheral nervous system provides a better understanding of underlying principles of the organization of the immune network present in the peripheral nerve and its dialogue with the systemic immune system. This may foster the development of specific and highly effective therapies for immune-mediated disorders of the peripheral nerve.