Immunopathogenesis and treatment of the Guillain-Barré syndrome--Part II

Inferring immune-associated signatures based on a co-expression network in Guillain-Barré syndrome

Objectives

Guillain‐Barré syndrome (GBS) is a type of acute autoimmune disease, which occurs in peripheral nerves and their roots. There is extensive evidence that suggests many immune‐associated genes have essential roles in GBS. However, the associations between immune genes and GBS have not been sufficiently examined as most previous studies have only focused on individual genes rather than their entire interaction networks.

Materials and methods

In this study, multiple levels of data including immune‐associated genes, GBS‐associated genes, protein‐protein interaction (PPI) networks and gene expression profiles were integrated, and an immune or GBS‐directed neighbour co‐expressed network (IOGDNC network) and a GBS‐directed neighbour co‐expressed network (GDNC network) were constructed.

Results

Our analysis shows the immune‐associated genes are strongly related to GBS‐associated genes whether at the interaction level or gene expression level. Five immune‐associated modules were also identified which could distinguish between GBS and normal samples. In addition, functional analysis indicated that immune‐associated genes are essential in GBS.

Conclusions

Overall, these results highlight a strong relationship between immune‐associated genes and GBS existed and provide a potential role for immune‐associated genes as novel diagnostic and therapeutic biomarkers for GBS.

Coexisting infectious diseases on admission as a risk factor for mechanical ventilation in patients with Guillain-Barré syndrome

Background

The aim of this study was to investigate patient characteristics on admission to hospital that increase the risk of subsequent mechanical ventilation (MV) use for patients with Guillain–Barré syndrome (GBS).

Methods

We extracted data from the Japanese Diagnosis Procedure Combination (DPC) database for 4132 GBS patients admitted to hospital. Clinical characteristics of GBS patients with and without MV were compared. Multivariate logistic regression analyses were performed to estimate the odds ratios (ORs) and 95% confidence intervals (CIs) for the associations of requirement for MV with coexisting infectious diseases, after adjustment for potential confounding variables, age, sex, hospital type, and ambulance transportation.

Results

In total, 281 patients required MV, and 493 patients had coexisting respiratory diseases on admission. After adjustment for covariates and stratification by coexisting respiratory diseases, multivariate logistic regression analysis revealed that coexisting cytomegaloviral (CMV) disease (OR 8.81; 95% CI, 2.34–33.1) and herpes simplex viral (HSV) infections (OR 4.83; 95% CI, 1.16–20.1) were significantly associated with the requirement for MV in the group without coexisting respiratory diseases.

Conclusion

Our findings suggest that coexisting CMV and HSV infections on admission might be significantly associated with increased risk of respiratory failure in GBS patients.

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Subjects of this study were 4132 inpatients with Guillain–Barré syndrome.

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Data were derived from the Japanese Diagnosis Procedure Combination (DPC) database.

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Association between comorbidities and mechanical ventilation use was evaluated.

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Cytomegaloviral and herpes simplex viral infections were associated with ventilation.

Impact of Immunoglobulin Therapy in Pediatric Disease: a Review of Immune Mechanisms

Intravenous immunoglobulin (IVIG) provides replacement therapy in immunodeficiency and immunomodulatory therapy in inflammatory and autoimmune diseases. This paper describes the immune mechanisms underlying six major non-primary immunodeficiency pediatric diseases and the diverse immunomodulatory functions of IVIG therapy. In Kawasaki disease, IVIG plays a major, proven, and effective role in decreasing aneurysm formation, which represents an aberrant inflammatory response to an infectious trigger in a genetically predisposed individual. In immune thrombocytopenia, IVIG targets the underlying increased platelet destruction and decreased platelet production. Although theoretically promising, IVIG shows no clear clinical benefit in the prophylaxis and treatment of neonatal sepsis. Limitations in research design combined with the unique neonatal immunologic environment offer explanations for this finding. Inflammation from aberrant immune activation underlies the myelinotoxic effects of Guillain-Barré syndrome. HIV-1 exerts a broad range of immunologic effects and was found to decrease serious bacterial infections in the pre-highly active anti-retroviral therapy (HAART) era, although its practical relevance in the post-HAART era has waned. Clinical and experimental data support the role of immune mechanisms in the pathogenesis of childhood epilepsy. IVIG exerts anti-epileptic effects through targeting upregulated cytokine pathways and antibodies thought to contribute to epilepsy. Applications in six additional pediatric diseases including pediatric asthma, atopic dermatitis, cystic fibrosis, pediatric autoimmune neuropsychiatric disorders associated with streptococcal infection (PANDAS), autism, and transplantation will also be briefly reviewed. From autoimmunity to immunodeficiency, a dynamic immunologic basis underlies major pediatric diseases and highlights the broad potential of IVIG therapy.

Differential effects of CXCR4-CXCL12- and CXCR7-CXCL12-mediated immune reactions on murine P0106-125 -induced experimental autoimmune neuritis

AIM

The role of chemokines and their receptors, which regulate trafficking and homing of leucocytes to inflamed organs in human or murine autoimmune neuritis, has not yet been elucidated in detail, Therefore, the role of the chemokine receptors CXCR4 and CXCR7 and their ligand CXCL12 was studied in autoimmune-mediated inflammation of the peripheral nervous system.

METHODS

CXCL12/CXCR4 and/or CXCL12/CXCR7 interactions were specifically inhibited by the compounds AMD3100 or CCX771, respectively, in experimental autoimmune neuritis (EAN) of C57BL/6J mice immunized with P0106-125 peptide.

RESULTS

Disease activity was significantly suppressed by blocking CXCR7 while antagonization of CXCR4 enhanced disease activity. Enhanced disease activity was accompanied by significantly increased transcription of IFN-γ, IL-12 and TNF-α mRNA in regional lymph nodes and spleen as well as by increased serum levels of IFN-γ. Furthermore, by blocking CXCR4, expression of the cell adhesion molecules ICAM-1 and VCAM-1 was upregulated on vascular endothelial cells of the sciatic nerve, which coincided with significantly increased infiltration of the sciatic nerve by CD4+ T cells and macrophages. Remarkably, combined antagonization of both CXCR4 and CXCR7 significantly suppressed disease activity. This was accompanied by increased frequencies of activated and highly IFN-γ-expressing, P0106-125 -specific T cells in regional lymph nodes and spleen; however, these cells were unable to infiltrate the sciatic nerve.

CONCLUSION

These data suggest differential and hierarchically ordered roles for CXCR4/CXCL12- vs. CXCR7/CXCL12-dependent effects during EAN: CXCR7/CXCL12 interaction is a gatekeeper for pathogenic cells, regardless of their CXCR4/CXCL12-dependent state of activation.

A rare neurological complication of typhoid fever: Guillain-Barre' syndrome

Guillain-Barre’ syndrome is a rare complication of typhoid fever, and only a few such cases have been reported in the pediatric age group. We report a young boy with blood culture proven typhoid fever that developed this very rare neurological complication quite early in the course of the disease. Following treatment with intravenous antibiotics and intravenous immunoglobulin, he improved.

Costimulatory molecule CD40 is essential for myelin protein 0 peptide 106-125-induced experimental autoimmune neuritis in mice

Myelin protein 0 peptide 106-125-induced murine experimental autoimmune neuritis (EAN) is a CD4-positive T cell-mediated monophasic axonal inflammatory neuropathy; interferon-γ is the key proinflammatory mediator. Experimental autoimmune neuritis is well suited for elucidating pathogenetic mechanisms underlying human acute axonal Guillain-Barré syndrome. Here, the functional role of the costimulatory molecule CD40 was defined by characterization of EAN in CD40-deficient mice. In contrast to immunized C57BL/6 mice, CD40-deficient mice were resistant to EAN owing to impaired priming of CD4-positive T-effector cells. To determine whether CD40 is a suitable candidate for the treatment of EAN, we administered monoclonal anti-CD40 antibody either before immunization or upon onset of neurologic signs. Prophylactic anti-CD40 treatment completely abolished CD4-positive T-cell priming. Therapeutic application of anti-CD40 prevented full activation of CD4-positive T cells that were in the process of priming and suppressed production of interferon-γ in peripheral lymph nodes, spleen, and serum, and of interleukin-6, interleukin-12p40, intercellular adhesion molecule-1, and vascular cell adhesion molecule-1, which are associated with activation of the nuclear factor-κB signaling pathway. This resulted in enhanced recovery by early generation of CD25-positive, Foxp3-positive, CD4-positive regulatory T cells. Thus, these experiments highlight the crucial role of CD40 as an important costimulatory molecule in EAN and suggest that it has potential as a therapeutic target in human neuritis.

Prevalence and profile of sleep disturbances in Guillain-Barre Syndrome: a prospective questionnaire-based study during 10 days of hospitalization

INTRODUCTION

Sleep disturbances in Guillain-Barre Syndrome (GBS), though common, have not received focused attention.

OBJECTIVES

To study frequency and nature of sleep disturbances in patients with GBS, using validated questionnaires, and analyze the contributing factors.

MATERIALS AND METHODS

This prospective study included 60 patients fulfilling National Institute of Neurological and Communicative Diseases and Stroke (NINCDS) criteria for GBS (mean age: 32.7 ± 12.9 years; median: 30 years; M:F = 46:14), evaluated from 2008 to 2010. Data regarding sleep were collected on 10 consecutive days following admission using Richard Campbell Sleep score, St Mary's Hospital Sleep Questionnaire, and Pittsburgh Sleep Quality Index (PSQI) and correlated with various possible contributing factors like pain, paresthesia, anxiety, depression, autonomic dysfunctions, severity of disease, and therapeutic interventions among others.

OBSERVATIONS

Qualitative and quantitative sleep disturbances were rather frequent and involved over 50% patients: abnormal PSQI - 13.3%, abnormal score on Richard scale - 51.6%, abnormal sleep onset latency - 35%, sleep fragmentation - 40%, and reduced sleep duration - 46.6%. The symptoms were severe during the first week of hospitalization and reduced thereafter. Sleep disturbances as scored on Richard scale significantly correlated with anxiety, pain, paresthesia, and severity of immobility (P < 0.05) but not with depression and use of analgesics or antineuritic drugs.

CONCLUSIONS

This study first of its kind suggests that sleep disturbance in GBS is frequent, multi-factorial, often disturbing, and varies during the course of illness. Routine enquiry into the sleep disturbances and timely intervention may reduce morbidity and improve their quality of life.

Diagnosis and treatment of primary Sjögren syndrome-associated peripheral neuropathy: a six-case series

OBJECTIVES

The clinical and therapeutic aspects of primary Sjögren syndrome (PSS) in patients with peripheral neuropathy were analyzed and the specifics of individual case studies are discussed.

METHODS

We retrospectively studied six patients (four women, two men; mean age 64.5 years) presenting with PSS with peripheral neurological involvement over a five-year period (2008-2012). All patients had neurological examinations, including nerve conduction studies, somatosensory evoked potentials, and sural nerve biopsies. Treatment regimens included corticosteroids, intravenous gammaglobulin, or immunosuppressive treatment.

RESULTS

Peripheral neuropathy was observed in six (7.9 %) of 76 patients with SS as the underlying disease; three were cases of multiple mononeuropathy, two cases had sensory ataxic neuropathy, one of which was autonomic neuropathy, and one case was diagnosed as painful sensory neuropathy without sensory ataxia. Four of the six patients were diagnosed with SS after the onset of neurological symptoms. Individual peripheral neuropathies had distinct neurological, electrophysiological, and pathological characteristics. The effect of steroids and intravenous gammaglobulin differed depending on the case.

CONCLUSIONS

In PSS patients, a precise diagnosis is important, because the therapeutic strategy and response varies depending on the type of neuropathy. In clinical practice, it is important to consider a diagnosis of SS when patients present with peripheral neuropathy.

Peripheral neuropathy

Patients presenting with symptoms of peripheral neuropathy are commonplace in the practice of generalist physicians, office based or hospitalists. Although there are at least a thousand different causes for peripheral neuropathy, the majority of patients can be properly diagnosed (and managed) based on framing the diagnostic possibilities within one of six typical scenarios. The case presentations in this article illustrate common and less common but essential presentations and the approach to evaluation and treatment. For these patients the key to success lies in the history and clinical examination findings.

Therapy of immune neuropathies with intravenous immunoglobulins

Autoimmune-mediated disorders belong to the main causes of neuropathies worldwide. During recent years much progress has been achieved in the understanding of the underlying pathomechanisms, associated with implications for therapeutic approaches. Here we will briefly review the pathogenesis and discuss treatment options of the Guillain-Barré syndrome, chronic inflammatory demyelinating polyneuropathy, multifocal motor neuropathy, and neuropathies associated with paraproteinemias. In most of these disease entities intravenous immunoglobulins play a major role as effective and safe treatment options.

Guillain-Barré syndrome associated with Salmonella paratyphi A

A 31-year-old Nepali man was admitted to the intensive care unit with a 3-day history of fever associated with four-limb weakness, followed by difficulty in swallowing. The patient came from Nepal 20 days before admission. On examination the patient was conscious and appeared ill, with a temperature of 38.0 degrees C. His four limbs were weak (grades 2-3) and he was areflexic with mild facial weakness and absent gag reflex. Brain CT and MRI were normal. Cerebrospinal fluid analysis showed high protein. A neurophysiologic study showed data consistent with motor axonal polyradiculopathy. The patient was diagnosed with Guillain-Barré syndrome (GBS), and intravenous immunoglobulin (0.4 g/kg day for 5 days) was administered. On the third hospitalization day, the patient developed respiratory failure for which he was intubated and mechanically ventilated. On the same day, blood samples grew Salmonella paratyphi A (S. paratyphi A), which was sensitive to ceftriaxone. The patient was then diagnosed with GBS associated with S. paratyphi A, and treated with ceftriaxon (2 g administered intravenously, daily for 10 days). On the eleventh hospitalization day the patient was weaned from ventilator and extubated successfully. Subsequently, the patient improved, his fever subsided, and he regained muscle power satisfactorily.

Cytomegalovirus disease with Guillain–Barré syndrome in a cadaver renal allograft recipient: cause or coincidence

Anecdotal reports of acute inflammatory demyelinating polyneuropathy (Guillain-Barré syndrome) with cytomegalovirus (CMV) suggested as the etiological agent have been described in transplant recipients with poor prognosis. We describe a 48-year-old man, a cadaveric renal allograft recipient on cyclosporine, mycophenolate mofetil and prednisolone, who developed febrile illness with unexplained anemia followed by progressive weakness of the upper and lower limbs. He was diagnosed as a case of Guillain-Barré syndrome (GBS). His CMV serology was positive by polymerase chain reaction (PCR). We treated him with both gancyclovir and intravenous immunoglobulins within a week of the onset of GBS and observed rapid recovery. Thus, search for CMV is warranted in transplant patients presenting with GBS, as early initiation of treatment with gancyclovir and immunoglobulins can help expedite recovery.

The immunobiology of Guillain-Barré syndromes

This presentation highlights aspects of the immunobiology of the Guillain-Barré syndromes (GBS), the world's leading cause of acute autoimmune neuromuscular paralysis. Understanding the key pathophysiological pathways of GBS and developing rational, specific immunotherapies are essential steps towards improving the clinical outcome of this devastating disorder. Much of the research into GBS over the last decade has focused on the forms mediated by anti-ganglioside antibodies, and we have made substantial progress in our understanding in several related areas. Particular highlights include (a) the emerging correlations between anti-ganglioside antibodies and specific clinical phenotypes, notably between anti-GM1/anti-GD1a antibodies and the acute motor axonal variant and anti-GQ1b/anti-GT1a antibodies and the Miller Fisher syndrome; (b) the identification of molecular mimicry between GBS-associated Campylobacter jejuni oligosaccharides and GM1, GD1a, and GT1a gangliosides as a mechanism for anti-ganglioside antibody induction; (c) the development of rodent models of GBS with sensory ataxic or motor phenotypes induced by immunisation with GD1b or GM1 gangliosides, respectively. Our work has particularly studied the motor nerve terminal as a model site of injury, and through combined active and passive immunisation paradigms, we have developed murine neuropathy phenotypes mediated by anti-ganglioside antibodies. This has been achieved through use of glycosyltransferase and complement regulator knock-out mice, both for cloning anti-ganglioside antibodies and inducing disease. Through such studies, we have proven a neuropathogenic role for murine anti-ganglioside antibodies and human GBS-associated antisera and identified several determinants that influence disease expression including (a) the level of immunological tolerance to microbial glycans that mimic self-gangliosides; (b) the ganglioside density in target tissue; (c) the level of complement activation and the neuroprotective effects of endogenous complement regulators; and (d) the role of calcium influx through complement pores in mediating axonal injury. Such studies provide us with clear information on an antibody-mediated pathogenesis model for GBS and should lead to rational therapeutic testing of agents that are potentially suitable for use in humans.

Dendritic cells in the cerebrospinal fluid and peripheral nerves in Guillain-Barré syndrome and chronic inflammatory demyelinating polyradiculoneuropathy

The role of antigen-presenting cells (APC) involved in induction of T and B cell mediated autoaggressive immunity in Guillain-Barre syndrome (GBS) and chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is poorly understood. We studied the numbers and phenotype of dendritic cells (DC) in blood and cerebrospinal fluid (CSF) over the course of GBS and CIDP before and after immunomodulatory treatment. Four out of seven GBS patients examined prior to treatment with high-dose intravenous immunoglobulins (IvIg) had elevated numbers of CD123(+) plasmacytoid DC in the CSF, while both GBS and CIDP patients examined prior to treatment had elevated numbers of CD11c(+) myeloid DC in the CSF, as compared to patients with noninflammatory neurological diseases (OND). The percentages of blood DC expressing the cell surface marker CD1a, co-stimulatory molecules CD80 and CD86, adhesion molecule CD54, and chemokine receptors CCR1, CCR2, CCR5, and CXCR4 were not affected in GBS or CIDP. The immunohistochemistry of sural nerve biopsies revealed CD11c(+)CD83(-)CD14(-)CD16(-) immature myeloid DC at low numbers, mostly in the perineurium, without difference between CIDP patients and controls. In contrast, the numbers of CD11c(+)CD14(+)/CD16(+) macrophages were higher within the endoneurium in CIDP patients compared with the controls. The recruitment of DC to CSF in GBS and CIDP may be important in capturing antigens released from inflamed spinal nerve roots into CSF and in transferring these antigens from CSF to local lymph nodes, where naive T and B cells may be activated.

The use of intravenous immunoglobulin in the treatment of autoimmune neuromuscular diseases: evidence-based indications and safety profile

Intravenous immunoglobulin (i.v.Ig) has multiple actions on the immunoregulatory network that operate in concert with each other. For each autoimmune neuromuscular disease, however, there is a predominant mechanism of action that relates to the underlying immunopathogenetic cause of the respective disorder. The best understood actions of i.v.Ig include the following: (a) modulation of pathogenic autoantibodies, an effect relevant in myasthenia gravis (MG), Lambert-Eaton myasthenic syndrome (LEMS), Guillain-Barré syndrome (GBS), chronic inflammatory demyelinating polyneuropathy (CIDP), and stiff-person syndrome (SPS); (b) inhibition of complement activation and interception of membranolytic attack complex (MAC) formation, an action relevant to the complement-mediated mechanisms involved in GBS, CIDP, MG, and dermatomyositis (DM); (c) modulation of the inhibitory or activation Fc receptors on macrophages invading targeted tissues in nerve and muscle, as seen in CIDP, GBS, and inflammatory myopathies; (d) down-regulation of pathogenic cytokines and adhesion molecules; (e) suppression of T-cell functions; and (f) interference with antigen recognition. Controlled clinical trials have shown that i.v.Ig is effective as first-line therapy in patients with GBS, CIDP, and multifocal motor neuropathy (MMN), and as second-line therapy in DM, MG, LEMS, and SPS. In paraproteinemic IgM anti-MAG (myelin-associated glycoprotein) demyelinating polyneuropathies and inclusion body myositis (IBM), the benefit is variable, marginal, and not statistically significant. i.v.Ig has a remarkably good safety record for long-term administration, however, the following side effects have been observed: mild, infusion-rate-related reactions, such as headaches, myalgia, or fever; moderate but inconsequential events, such as aseptic meningitis and skin rash; and severe, but rare, complications, such as thromboembolic events and renal tubular necrosis. Future studies are needed to (a) find the appropriate dose and frequency of infusions that maintain a response; (b) address pharmacoeconomics, comparing the high cost of i.v.Ig to the cost of the other therapies, which, although less expensive, cause significantly more long-term side effects; (c) determine why some patients respond better than others; and (d) examine the merits of combining i.v.Ig with other immunosuppressive drugs.

Elevated number of cells secreting transforming growth factor beta in Guillain-Barre syndrome

We used ELISPOT and cell ELISA to study secretion of IL-4, IFN-gamma, TGF-beta, IL-6, and TNF-alpha by circulating mononuclear cells during the course of Guillain-Barré syndrome (GBS). Compared to healthy controls, patients with GBS had higher numbers of TGF-beta-secreting cells and the number of individuals with myelin-peptide-induced IL-4 and TGF-beta secretion was higher in the GBS group. No significant differences were seen concerning the predominantly pro-inflammatory cytokines IFN-gamma, IL-6 or TNF-alpha. Our findings indicate a down-regulatory role for TGF-beta and IL-4 in GBS.

Tolerance to self gangliosides is the major factor restricting the antibody response to lipopolysaccharide core oligosaccharides in Campylobacter jejuni strains associated with Guillain-Barré syndrome

Guillain-Barré syndrome following Campylobacter jejuni infection is frequently associated with anti-ganglioside autoantibodies mediated by molecular mimicry with ganglioside-like oligosaccharides on bacterial lipopolysaccharide (LPS). The regulation of antibody responses to these T-cell-independent antigens is poorly understood, and only a minority of Campylobacter-infected individuals develop anti-ganglioside antibodies. This study investigates the response to gangliosides and LPS in strains of mice by using a range of immunization strategies. In normal mice following intraperitoneal immunization, antibody responses to gangliosides and LPS are low level but can be enhanced by the antigen format or coadministration of protein to recruit T-cell help. Class switching from the predominant immunoglobulin M (IgM) response to IgG3 occurs at low levels, suggesting B1-cell involvement. Systemic immunization results in poor responses. In GalNAc transferase knockout mice that lack all complex gangliosides and instead express high levels of GM3 and GD3, generation of anti-ganglioside antibodies upon immunization with either complex gangliosides or ganglioside-mimicking LPS is greatly enhanced and exhibits class switching to T-cell-dependent IgG isotypes and immunological memory, indicating that tolerance to self gangliosides is a major regulatory factor. Responses to GD3 are suppressed in knockout mice compared with wild-type mice, in which responses to GD3 are induced specifically by GD3 and as a result of polyclonal B-cell activation by LPS. The anti-ganglioside response generated in response to LPS is also dependent on the epitope density of the ganglioside mimicked and can be further manipulated by providing secondary signals via lipid A and CD40 ligation.

Transfer of myelin-specific cells deviated in vitro towards IL-4 production ameliorates ongoing experimental allergic neuritis

A causal role of IL-4 (Th2) production for recovery in experimental allergic neuritis (EAN) was indicated by experiments where Th1-like autoreactive cell populations, taken from the induction phase of the disease, were deviated to extensive secretion of IL-4 in a selective fashion, by ex vivo stimulation with autoantigen in the presence of IL-4. The deviated cells were adoptively transferred to EAN rats at a time just prior to the onset of clinical signs. This treatment ameliorated EAN compared with sham treatment. This therapeutic approach, with generation of autoreactive IL-4-secreting cells ex vivo followed by subsequent adoptive transfer, may become a new selective treatment of organ-specific autoimmune diseases since, in contrast to previous attempts, it is done in a physiological and technically easy way.

Can antiglycolipid antibodies present in HIV-infected individuals induce immune demyelination?

Of the eight clinically defined neuropathies associated with HIV infection, there is compelling evidence that acute and chronic inflammatory demyelinating polyneuropathy (IDPN) have an autoimmune pathogenesis. Many non-HIV infected individuals who suffer from sensory-motor nerve dysfunction have autoimmune indicators. The immunopathogenesis of demyelination must involve neuritogenic components in myelin. The various antigens suspected to play a role in HIV-seronegative IDPN include (i) P2 protein; (ii) sulfatide (GalS); (iii) various gangliosides (especially GM1); (iv) galactocerebroside (GalC); and (v) glycoproteins or glycolipids with the carbohydrate epitope glucuronyl-3-sulfate. These glycoproteins or glycolipids may be individually targeted, or an immune attack may be raised against a combination of any of these epitopes. The glycolipids, however, especially GalS, have recently evoked much interest as mediators of immune events underlying both non-HIV and HIV-associated demyelinating neuropathies. The present review outlines the recent research findings of antiglycolipid antibodies present in HIV-infected patients with and without peripheral nerve dysfunction, in an attempt to arrive at some consensus as to whether these antibodies may play a role in the immunopathogenesis of HIV-associated inflammatory demyelinating polyneuropathy.

Recent advances of therapeutic apheresis in Guillain-Barré syndrome

Acute idiopathic demyelinating polyneuritis (AIDP), commonly known as the Guillain-Barré syndrome (GBS), is an immune-mediated demyelinating disease of the peripheral nerve and nerve roots. A number of immunological mechanisms were described, but the exact pathomechanism has not been explained fully. Presumably, a variety of immunological processes lead to a relatively uniform clinical phenotype. Two large multicenter studies showed that plasma exchange (PE) was significantly superior to supportive treatment only. Selective adsorption (SA) also was employed as a method of therapeutic apheresis, and various smaller studies established that both PE and SA are equally effective treatments for GBS. Recently, it was demonstrated that the number of apheresis treatments should be adapted to the severity of disease. A large multicenter controlled study established equal efficacy of PE and intravenous immunoglobulin treatment (IVIg) as well as the combination of PE and IVIg. Since that time, the use of apheresis for the treatment of GBS declined in many countries due to the easier application of IVIg. The number of patients treated in larger hospitals with long-standing experience in the treatment of GBS also has declined.

Inexcitability of nerves in a fulminant case of Guillain-Barré syndrome

A 45-year-old woman presented with a recent sensorimotor deficiency in all 4 limbs, and the next day she was totally paralyzed. A slight motor improvement began on day 27. The cerebrospinal fluid had normal cellularity, but the protein varied from 90 mg/dL on the first day to 800 mg/dL on day 15, and then 290 mg/dL on day 33. Electrophysiologic studies performed on days 15 and 23 revealed a universal peripheral nerve inexcitability. A superficial peroneal nerve biopsy was performed on day 23. Nine fascicles were examined on semi-thin sections and myelinated fiber damage varied greatly from one fascicle to another. At ultrastructural examination, certain axons were severely damaged, but the others were quite well preserved and were naked or wrapped in a myelin sheath presenting a multivesicular degeneration. A few fibers had a better-preserved myelin sheath that was sometimes dissociated by elongated processes from an invading histiocyte. Six cases of fulminant Guillain-Barré syndrome with inexcitability of nerves and ultrastructural examination of nerve fragments have been reported. Electrophysiologic study is often ambiguous and cannot determine the precise origin of such an axonal degeneration. Therefore, ultrastructural analysis of a nerve biopsy is mandatory in this setting.

Apheresis and selective adsorption plus immunoglobulin treatment in Guillain-Barré syndrome

Plasma exchange (PE) and administration of intravenous immunoglobulin (i.v. IgG) are established treatments for Guillain-Barré syndrome (GBS). Combination treatment with elimination of postulated pathogenetic factors by PE or selective adsorption (SA) treatment and subsequent immunomodulation by intravenous IgG may provide a more effective treatment. In a single-center randomized study, 45 patients with acute GBS were prospectively examined using a clinical score. We treated 11 patients by PE, 13 with SA using a tryptophan-linked polyvinyl alcohol gel adsorbent, and 21 with SA followed by intravenous IgG. The patients treated sequentially by selective adsorption and intravenous IgG improved significantly better than the patients who received plasma treatment only. The results suggest that combination treatment of GBS may be superior to plasma treatment alone.

Pathogenic autoantibodies to neuronal proteins in neurological disorders

Autoantibodies to acetylcholine receptors and to voltage-gated calcium and potassium channels are thought to be pathogenic in three peripheral neurological disorders: myasthenia gravis, the Lambert Eaton syndrome and acquired neuromyotonia. However, evidence for the role of antibodies in conditions involving the central nervous system, is scanty or unclear. This review describes the ways in which the roles of autoantibodies have been defined in the peripheral diseases, and discusses the more controversial evidence for involvement of autoantibodies in some central disorders such as multiple sclerosis.

Intravenous immunoglobulin in the treatment of autoimmune neuromuscular diseases: present status and practical therapeutic guidelines

This review summarizes the current status of intravenous immunoglobulin (IVIg) in the treatment of autoimmune neuromuscular disorders and the possible mechanisms of action of the drug based on work in vivo, in vitro, and in animal models. Supply of idiotypic antibodies, suppression of antibody production, or acceleration of catabolism of immunoglobulin G (IgG) are relevant in explaining the efficacy of IVIg in myasthenia gravis (MG), Lambert-Eaton myasthenic syndrome (LEMS), and antibody-mediated neuropathies. Suppression of pathogenic cytokines has putative relevance in inflammatory myopathies and demyelinating neuropathies. Inhibition of complement binding and prevention of membranolytic attack complex (MAC) formation are relevant in dermatomyositis (DM), Guillain-Barré syndrome (GBS), and MG. Modulation of Fc receptors or T-cell function is relevant in chronic inflammatory demyelinating polyneuropathy (CIDP), GBS, and inflammatory myopathies. The clinical efficacy of IVIg, based on controlled clinical trials conducted in patients with GBS, CIDP, multifocal motor neuropathy (MMN), DM, MG, LEMS, paraproteinemic IgM anti-myelin-associated glycoprotein (anti-MAG) demyelinating polyneuropathies, and inclusion body myositis is summarized and practical issues related to each disorder are addressed. The present role of IVIg therapy in other disorders based on small controlled or uncontrolled trials is also summarized. Finally, safety issues, risk factors, adverse reactions, spurious results or serological tests, and practical guidelines associated with the administration of IVIg in the treatment of neuromuscular disorders are presented.

Intravenous immunoglobulin in very severe childhood Guillain-Barré syndrome

To evaluate intravenous immunoglobulin (IVIG) therapy in children with very severe Guilain-Barré syndrome (GBS) with reference to the need for respiratory support, ICU stay and long-term outcome, we studied 33 children with very severe GBS and quadriparesis and/or respiratory muscle weakness admitted to the Pediatric Intensive Care Unit (PICU) of PGIMER, Chandigarh. Cases (n = 22, IVIG group) were enrolled prospectively, and controls (n = 11), similar to cases in age and severity of illness, retrospectively. All children received similar supportive and respiratory care. In addition, cases were given IVIG (Sandoglobulin, Sandoz) 0.4 g/kg bodyweight per day for 5 days. The mean age, duration of symptoms prior to admission and severity of illness in the two groups were similar. In the IVIG group, onset of recovery of muscle power was significantly earlier (day 14.8 (6.8) of illness vs day 20.9 (8.6), p < 0.05) and the length of PICU stay significantly shorter (20.5 (13.0) days vs 50.5 (33.3) days, p < 0.01). Sixteen (72.7%) children in the IVIG group had improved by at least one functional grade after 1 month and 15 (68%) were walking independently after 3 months compared with two (18%) and four (36%) controls, respectively (p < 0.05). The number of children who needed endotracheal intubation and mechanical ventilation and the duration of mechanical ventilation was significantly less in the IVIG-treated group. We conclude that in very severe GBS in children IVIG therapy improves outcome to a remarkable extent, reduces the need for intubation and mechanical ventilation, shortens the length of stay in ICU, and promotes ambulation sooner.

AAEM case report 4: Guillain-Barré syndrome. American Association of Electrodiagnostic Medicine

A 57-year-old woman developed rapidly progressive, symmetric, extremity weakness, facial diplegia, ophthalmoplegia, respiratory insufficiency, and sensory ataxia over a 3-week period. Electrodiagnostic studies were performed on days 6, 13, and 50 following the onset of weakness. Motor nerve conduction abnormalities were the predominant findings. Prolonged motor distal latencies, prolonged or absent F waves, and partial motor conduction blocks were present and form the diagnostic features of an acquired, demyelinating polyneuropathy. Abnormalities in sensory nerve conductions and blink reflexes were also present. Guillain-Barré syndrome was diagnosed prompting the initiation of therapeutic plasma exchange. The patient's clinical status continued to worsen over the next 10 days before stabilizing. Considerable improvement in extremity strength, ocular motility, and respiratory function occurred in the subsequent weeks. Well-planned and well-executed electrodiagnostic studies generate key adjunctive data to the clinical diagnosis of Guillain-Barré syndrome.

TCR-Vbeta usage in the thymus and blood of myasthenia gravis patients

In myasthenia gravis (MG) the muscle acetylcholine receptor (AChR) is the target of an autoimmune response. The anti-AChR response may originate in the thymus, which is abnormal in most MG patients and contains anti-AChR T and B cells. Microbial superantigens (sAg) may trigger autoimmune responses and in this study we sought clues as to whether sAg play a role in the pathogenesis of MG. We investigated the frequency of use of the different TCR Vbeta families by the thymus and blood T cells in MG patients and in control subjects, using a multi-primer PCR assay. Identical TCR-Vbeta usage was found in the thymi of MG patients and controls, except Vbeta2, which showed a small increase in MG patients' thymi. Blood T cells of MG patients used Vbeta4, Vbeta6, Vbeta15, Vbeta16 and Vbeta24 significantly more than those of the controls. Vbeta4 and Vbeta6 are the gene families most frequently used by anti-AChR CD4(+) cells in MG patients. Blood T cells from MG patients used Vbeta12, Vbeta14, Vbeta17 and Vbeta18 significantly less than controls. MG patients used Vbeta4 and Vbeta6 significantly more in the blood than in the thymus, while the opposite occurred for Vbeta7, Vbeta12 and Vbeta14. Controls used Vbeta17 more and Vbeta24 less in the blood than in the thymus. The preferential expansion of Vbeta4 and Vbeta6 in MG patients might reflect the immunodominance of certain AChR epitopes, or the action of a sAg outside the thymus. The minimal differences in the TCR-Vbeta usage in the blood and thymus of control subjects might be due to expansion of T cell clones specific for common antigens. Identical Vbeta usage in the thymi of MG patients and controls does not support an important role of the thymus as the location of anti-AChR sensitization when MG is clinically evident. The differences observed in the Vbeta usage in blood and thymi of MG patients are likely to be due to preferential Vbeta usage by the anti-AChR T cells in the blood.

Characterization and partial purification of a novel 36 kDa peripheral myelin protein recognized by the sera of patients with neurological disorders

Sera of some patients with acquired sensory neuropathy, chronic inflammatory demyelinating polyradiculoneuropathy and motor neuron disease have high titres of IgG autoantibodies to a minor human peripheral nerve glycoprotein of approximately 36 kDa. This protein cofractionated with PNS myelin and was also found in bovine and rat nerve but not in CNS myelin or other nonneural human tissues. The N-terminal sequence revealed that this protein is related to the major myelin protein P0. Monoclonal antibodies to P0 and to the carbohydrate epitope HNK-1 did not recognize the 36-kDa protein, and the human anti-36-kDa antibodies did not bind to P0. IgG binding to this protein was not abolished after periodate oxidation or deglycosylation, suggesting that the epitope recognized by the human antibodies is peptidic. Differential glycosylation did not account for the differences in the apparent molecular weight between these two proteins. Overall our results indicate that the 36-kDa protein is a variant of P0.

Electrophysiological classification of Guillain-Barré syndrome: clinical associations and outcome. Plasma Exchange/Sandoglobulin Guillain-Barré Syndrome Trial Group

We performed electrophysiological and serological testing within 15 days of symptom onset on 369 patients with Guillain-Barré Syndrome (GBS) enrolled in a trial comparing plasma exchange, intravenous immunoglobulin, and both treatments. Patients were classified into five groups by motor nerve conduction criteria; 69% were demyelinating, 3% axonal, 3% inexcitable, 2% normal, and 23% equivocal. Six of 10 (60%) patients with axonal neurophysiology had had a preceding diarrheal illness compared with 71 of 359 (20%) in other groups. Antiganglioside GM1 antibodies were present in a higher proportion of patients with axonal physiology or inexcitable nerves than other patients. The number dead or unable to walk unaided at 48 weeks was greater in the group with initially inexcitable nerves (6 of 12, 50%) compared with the rest (52 of 357, 15%), but was not significantly different between the axonal (1 of 10, 10%) and demyelinating (44 of 254, 17%) groups. Sensory action potentials and clinical sensory examination were both normal in 53 of 342 (16%) patients, and these "pure motor GBS" patients were more likely than other GBS patients to have IgG antiganglioside GM1 antibodies and to have had preceding diarrhea but had a similar outcome. The axonal group was more likely than other groups to have normal sensory action potentials. The outcomes in response to the three treatments did not differ in any subgroup (including patients with pure motor GBS or preceding diarrhea) or any neurophysiological category.

Recovery from Guillain-Barré syndrome is associated with increased levels of neutralizing autoantibodies to interferon-gamma

Guillain-Barré syndrome (GBS) is an immune-mediated demyelinating disease of peripheral nerves that is often preceded by an infection and is usually self-restricted. The Th1 cytokine interferon-gamma (IFN-gamma) is thought to be disease-promoting in organ-specific autoimmune diseases. We report the spontaneous induction of IFN-gamma and a mechanism involving the generation of neutralizing autoantibodies (Aabs) to IFN-gamma that may regulate the disease. Numbers of cells spontaneously secreting IFN-gamma in peripheral blood were augmented in GBS, in particular at the peak of clinical disease, and decreased during recovery. This decrease was associated with elevated serum concentrations of IgG Aabs to IFN-gamma. These Aabs specifically bound to IFN-gamma and neutralized its effects in a biological assay. Aabs to IFN-gamma are proposed to be another important regulatory mechanism in IFN-gamma-driven GBS.

Guillain-Barré syndrome

Guillain-Barré syndrome (GBS) is viewed as a reactive, self-limited, autoimmune disease triggered by a preceding bacterial or viral infection. Campylobacter jejuni, a major cause of bacterial gastroenteritis worldwide, is the most frequent antecedent pathogen. It is likely that immune responses directed towards the infecting organisms are involved in the pathogenesis of GBS by cross-reaction with neural tissues. The infecting organism induces humoral and cellular immune responses that, because of the sharing of homologous epitopes (molecular mimicry), cross-react with ganglioside surface components of peripheral nerves. Immune reactions against target epitopes in Schwann-cell surface membrane or myelin result in acute inflammatory demyelinating neuropathy (85% of cases); reactions against epitopes contained in the axonal membrane cause the acute axonal forms of GBS (15% of cases). Care for such patients may be challenging, yet the prognosis overall is favourable. Optimal supportive care and anticipation and prevention of complications are the mainstay of therapy. Admission to the intensive-care unit is necessary in 33% of patients who require intubation and assisted ventilation. Immunomodulation with infusions of IgG or plasma exchange treatments foreshorten the disease course.

Immunoadsorption therapy in Guillain-Barré syndrome

A 12-year-old boy rapidly developed Guillain-Barré syndrome (GBS) after Campylobacter jejuni enteritis. Electrophysiologic studies suggested that demyelination was dominant, and serum anti-C. jejuni and both IgG and IgM anti-GM1 antibodies were significantly elevated. The patient was treated three times with immunoadsorption therapy using a tryptophan-immobilized column. The volume of treated plasma in each session was about 2 L. His blood pressure was maintained within normal range with the use of 5% albumin preparations and etilefrine hydrochloride. His clinical and electrophysiologic findings began to recover shortly after therapy, with a decrease in the levels of serum IgG and IgM anti-GM1 antibodies. This immunoadsorption therapy should be considered for anti-GM1 antibody-associated GBS.

Campylobacter species and Guillain-Barré syndrome

Since the eradication of polio in most parts of the world, Guillain-Barré syndrome (GBS) has become the most common cause of acute flaccid paralysis. GBS is an autoimmune disorder of the peripheral nervous system characterized by weakness, usually symmetrical, evolving over a period of several days or more. Since laboratories began to isolate Campylobacter species from stool specimens some 20 years ago, there have been many reports of GBS following Campylobacter infection. Only during the past few years has strong evidence supporting this association developed. Campylobacter infection is now known as the single most identifiable antecedent infection associated with the development of GBS. Campylobacter is thought to cause this autoimmune disease through a mechanism called molecular mimicry, whereby Campylobacter contains ganglioside-like epitopes in the lipopolysaccharide moiety that elicit autoantibodies reacting with peripheral nerve targets. Campylobacter is associated with several pathologic forms of GBS, including the demyelinating (acute inflammatory demyelinating polyneuropathy) and axonal (acute motor axonal neuropathy) forms. Different strains of Campylobacter as well as host factors likely play an important role in determining who develops GBS as well as the nerve targets for the host immune attack of peripheral nerves. The purpose of this review is to summarize our current knowledge about the clinical, epidemiological, pathogenetic, and laboratory aspects of campylobacter-associated GBS.

Guillain-Barré syndrome after Cyclospora infection

We present a patient who developed Guillain-Barré syndrome (GBS) after a Cyclospora-induced diarrheal illness. We raise the possibility that Cyclospora is an infectious trigger for GBS in this patient. An active search for this agent in patients with GBS preceded by diarrheal illness is recommended.

Human autoimmune neuropathies

Peripheral nerve diseases are among the most prevalent disorders of the nervous system. Because of the accessibility of the peripheral nervous system (PNS) to direct physiological and pathological study, neuropathies have traditionally played a unique role in developing our understanding of basic mechanism of nervous system injury and repair. At present they are providing new insight into the mechanisms of immune injury to the nervous system. A rapidly growing catalogue of PNS disorders are now suspected to be immune-mediated, and in the best understood of these disorders, the molecular and cellular targets of immune attack are known, and the pathophysiology follows directly from the specific immune injury. This review summarizes the immunologically relevant features of the PNS, then considers selected immune-mediated neuropathies, focusing on pathogenetic mechanisms. Finally, the PNS is providing a testing ground for new immunotherapies and approaches to protection and regeneration, including the use of trophic factors. The current status of treatment and implications for future approaches is reviewed.

Intravenous immunoglobulin treatment of neurological autoimmune diseases

Intravenous immunoglobulin (IVIg) has been widely used in neurological diseases during the last decade. The current indications of IVIg in neurological diseases are reviewed and discussed on the basis of the available experimental data and clinical trials. Compared to other immunomodulating treatments used in neurological diseases, IVIg has only few side effects with a small risk of transmission of infectious agents. Good clinical evidence for the effectiveness is available for Guillain-Barré-Syndrome, chronic inflammatory demyelinating polyneuropathy and multifocal motor neuropathy. In conditions like myasthenia gravis and myositis favourable effects of IVIg were reported, but future studies have to be awaited. For all other neurological conditions where IVIg has been administered, there is currently no support for the use of IVIg other than in controlled trials. In conclusion, IVIg is a promising immunomodulary therapy that has been shown to be effective in some neurological autoimmune diseases. Routine use in neurological practice should be restricted to diseases for which a positive effect has been proven in controlled trials. For all other conditions no definite recommendations can presently be made.

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.

Acute peripheral neuropathy in adults. Guillain-Barré syndrome and related disorders

Acute paralysis in adults has an extensive assortment of etiologies. Guillian-Barré syndrome is the most common cause of acute neuropathy in adults. This review emphasizes pathophysiology, clinical features, differential diagnosis, and a practical approach to the laboratory work-up for patients with suspected Guillian-Barré syndrome. The current status of immunotherapy is reviewed.

Fulminant Guillain-Barré syndrome with universal inexcitability of peripheral nerves: a clinicopathological study

The pathological basis of nerve inexcitability in Guillain-Barré syndrome has not been established with certainty. We report the clinicopathological findings in a 67-year-old patient with fulminant Guillain-Barré syndrome who died 18 days after onset. Three serial electrophysiological studies revealed nerve inexcitability. Antibodies to Campylobacter jejuni were present but there was no antiganglioside reactivity. Spinal root sections revealed extensive and almost pure macrophage-associated demyelination with occasional presence of T lymphocytes and neutrophil leukocytes. Conversely, in femoral, median, and sural nerves the outstanding lesion was axonal degeneration, with some denuded axons remaining. Unmyelinated fibers, posterior root ganglia, and dorsal columns were preserved. Endoneurial postcapillary venules showed plump endothelial cells with loss of their tight junctions. We conclude that both primary demyelination and axonal degeneration secondary to inflammation account for nerve inexcitability. Our findings lend support to the hypothesis of increased endoneurial pressure as the cause of wallerian degeneration in nerve trunks.

Failure of intravenous immunoglobulin (IVIg) therapy in experimental autoimmune neuritis (EAN) of the Lewis rat

Experimental autoimmune neuritis (EAN) is an animal model for Guillain-Barré syndrome (GBS). Intravenous immunoglobulins (IVIg) are an effective treatment for GBS, but their mechanism of action is not well understood. Here we tested whether IVIg treatment, a potent modulator of proinflammatory assaults, reduces inflammation in EAN. The evaluation of IVIg treatment failed to demonstrate a salutary effect in different models of EAN. IVIg appears not to suppress the acute inflammatory insult on the peripheral nerve, but may have beneficial long-term effects not looked for in the present investigation.