Electrodiagnostic findings related to anti-GM1 and anti-GQ1b antibodies in Guillain-Barré syndrome

Impact of Zika Virus on adult human brain structure and functional organization

Objective

To determine the impact of Zika virus (ZIKV) infection on brain structure and functional organization of severely affected adult patients with neurological complications that extend beyond Guillain–Barré Syndrome (GBS)‐like manifestations and include symptoms of the central nervous system (CNS).

Methods

In this first case–control neuroimaging study, we obtained structural and functional magnetic resonance images in nine rare adult patients in the subacute phase, and healthy age‐ and sex‐matched controls. ZIKV patients showed atypical descending and rapidly progressing peripheral nervous system (PNS) manifestations, and importantly, additional CNS presentations such as perceptual deficits. Voxel‐based morphometry was utilized to evaluate gray matter volume, and resting state functional connectivity and Network Based Statistics were applied to assess the functional organization of the brain.

Results

Gray matter volume was decreased bilaterally in motor areas (supplementary motor cortex, specifically Frontal Eye Fields) and beyond (left inferior frontal sulcus). Additionally, gray matter volume increased in right middle frontal gyrus. Functional connectivity increased in a widespread network within and across temporal lobes.

Interpretation

We provide preliminary evidence for a link between ZIKV neurological complications and changes in adult human brain structure and functional organization, comprising both motor‐related regions potentially secondary to prolonged PNS weakness, and nonsomatomotor regions indicative of PNS‐independent alternations. The latter included the temporal lobes, particularly vulnerable in a range of neurological conditions. While future studies into the ZIKV‐related neuroinflammatory mechanisms in adults are urgently needed, this study indicates that ZIKV infection can lead to an impact on the brain.

Association of anti-gangliosides antibodies and anti-CMV antibodies in Guillain-Barré syndrome

INTRODUCTION

Numerous types of infection were closely related to GBS, mainly including Campylobacter jejuni, Cytomegalovirus, which may lead to the production of anti-gangliosides antibodies (AGA). Currently, although there are increased studies on the AGA and a few studies of anti-CMV antibodies in GBS, the association between them remains poorly documented. Therefore, our research aims to analyze the correlation of anti-CMV antibodies and AGA in GBS.

METHODS

A total of 29 patients with GBS were enrolled in this study. The CMV antibodies were tested by the electrochemiluminescence immunoassay "ECLIA" (Roche Diagnostics GmbH). The serum gangliosides were determined by The EUROLINE test kit.

RESULTS

Of the 29 patients with GBS, 9 (31%) were AGA-seropositive, in which 22 were CMV-IgG positive in CSF at the same time, but all 29 samples were CMV-IgM negative in both serum and CSF. In the AGA-positive group, the rate of both serum and CSF positive was 87.5% (7/8), higher than 50% (7/14) of the negative group, although no statistical significance was found. In addition, we found that there was a trend of higher ratio of men, a younger age onset, less frequent preceding infection, a higher level of CSF proteins, and less frequent cranial nerve deficits, although the data did not reach a statistical significance.

CONCLUSION

In spite of no statistical significance association was found between serum AGA and CMV-IgG in serum and CSF. However, we found that there was a trend of high positive rate of both serum and CSF-CMV-IgG in AGA-positive than the negative group. So we should further expand the sample size to analyze the association between AGA and CMV or other neurotropic virus antibodies in various diseases, to observe whether they could be serological marker of these diseases (especially GBS) or the underlying pathogenesis.

Long term clinical and electrophysiological assessment of Croatian children with corticospinal tract involvement in Guillain-Barré syndrome (GBS)

Guillain-Barré syndrome (GBS) is characterized by areflexia. Hyperreflexia is reported in acute motor axonal neuropathy (AMAN). We present 16 children with GBS at the age of 14 months to 13 years. All children studied fulfilled accepted diagnostic criteria for GBS. Hyperreflexia or positive Babinski sign were obtained in all children studied during follow up. Brain and spinal cord MR scans did not reveal any significant structural and morphological abnormalities of central nervous system. The children were examined clinically and electromyoneurographically 2-5 times successively during 1-8.5 years of follow-up. According to established electrodiagnostic criteria demyelinating form of GBS was most common (68%) compared to axonal (18,7%) or mixed form (12,5%). No children had antecendent Campylobacter jejuni infection. Antiganglioside antibodies were detected in 18,7% of patients associated with demyelinating or mixed (axonal/demyelinating) form. Time to nadir and recovery period of walking ability is prolonged more often in demyelinating GBS. Clinical improvement occur earlier compared to improvement of abnormal electrophysiological parameters.Outcome was excellent in 11 in the period 1 month-8.5 years. Hyperreflexia usually appeared in recovery period suggesting involvement of upper motor neurons or spinal interneurons occurring in Croatian children with both demyelinating and axonal form of GBS usually associated with milder course of disease.

Molecular mimicry in Campylobacter jejuni and Helicobacter pylori lipopolysaccharides: contribution of gastrointestinal infections to autoimmunity

Molecular mimicry of host structures by the saccharide portion of lipopolysaccharides (LPS) of the gastrointestinal pathogens Campylobacter jejuni and Helicobacter pylori is thought to be associated with the development of autoimmune sequelae. C. jejuni, a leading cause of gastroenteritis, is the most common antecedent infection in Guillain-Barré syndrome (GBS), an inflammatory neuropathy. Chemical analyses of the core oligosaccharides of neuropathy-associated C. jejuni strains have revealed structural homology with human gangliosides. Serum antibodies against gangliosides are found in one third of GBS patients but are generally absent in enteritis cases. Collective data suggest that the antibodies are induced by antecedent infection with C. jejuni, and subsequently react with nerve tissue causing damage. The O-chains of most H. pylori strains express Lewis blood group antigens which are thought to have a role in camouflage of the bacterium as these antigens are also present on human gastric epithelial cells. In chronic H. pylori infections, bacterial expression of Lewis antigens is suggested to be involved in the induction of autoantibodies against the Lewis antigen-expressing gastric proton pump. Many aspects of the autoimmune mechanisms in C. jejuni -associated GBS and H. pylori -induced atrophic gastritis remain unclear, such as the involvement of T cells and the role of host factors.

Intravenous immunoglobulin therapy for Guillain-Barré syndrome with IgG anti-GM1 antibody

To compare the effects of intravenous immunoglobulin (IVIg) therapy and plasmapheresis for the IgG anti-GM1-positive subtype of Guillain-Barré syndrome (GBS), clinical and electrophysiological recoveries were analyzed in 24 patients treated with IVIg (n = 10) or plasmapheresis (n = 14). At entry, there were no significant differences between the two patient groups in age, sex, clinical severity (Hughes grade), sum scores of distally evoked amplitudes of compound muscle action potentials (CMAPs), and frequency of Campylobacter jejuni infection. The patients treated with IVIg had significantly lower Hughes grade scores 1, 3, and 6 months after onset (P = 0.03), and a higher probability to regain independent locomotion at 6 months [P(logrank) = 0.044]. In the IVIg group, markedly rapid recovery (improvement by two or more Hughes grade scores within 4 weeks) was more frequent (6 of 10 vs. 3 of 14, P = 0. 03), and delayed recovery (unable to walk independently at 6 months) was less frequent (0 of 10 vs. 4 of 14, P = 0.06). CMAP sum score at 6 months tended to be greater for the IVIg group (P = 0.07). For the IgG anti-GM1-positive subgroup of GBS patients, IVIg therapy may be a more efficacious treatment than plasmapheresis.

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.

Electrophysiological studies in the Guillain-Barré syndrome: distinguishing subtypes by published criteria

Guillain-Barré syndrome (GBS) is recognized clinically by the presence of acute, rapidly progressive weakness, areflexia, and albuminocytological dissociation in cerebrospinal fluid. Although GBS was initially considered to be primarily an acute inflammatory demyelinating polyneuropathy (AIDP), several other subtypes have been recognized: acute motor axonal neuropathy (AMAN), acute motor-sensory axonal neuropathy (AMSAN), and Fisher syndrome (FS). Because each of these subtypes may have an independent immunopathogenesis and, therefore, may require selective treatments in the future, recognition of these subtypes is important. When using nerve conductions to classify the subtypes, the most easily and confidently identified subtype is AIDP. Therefore, most electrodiagnostic criteria have attempted to identify demyelination in this acute setting, in which physiology is constantly changing. In a single well-defined GBS population, we compared the various published criteria for demyelination in GBS. We reviewed charts of 43 patients with GBS between 1991 and 1996. Applying six available criteria sets, the number of patients categorized as having AIDP ranged from 21% to 72%. Until investigators can agree on a single set of criteria, considerable variability will continue to exist when identifying cases of AIDP.

The role of glycosphingolipids in neurological disorders. Mechanisms of immune action

Specific criteria that are required for understanding the significance of glycosphingolipid (GSL) antibodies, as well as mechanisms that may underlie the immunopathogenesis of these disorders, are proposed. These criteria are illustrated by describing the role of a unique family of acidic GSLs, the sulfated glucuronosyl glycolipids (SGGLs), in the pathogenic mechanisms of peripheral neuropathy with IgM paraproteinemia. High anti-SGGL antibody titers are detected in patients suffering from this disorder. It is demonstrated that SGGLs, which possess a common carbohydrate epitope with myelin-associated glycoprotein (MAG), several low-molecular-weight glycoproteins in the PNS, and a number of cell adhesion molecules, are potential target antigens for the neuropathy. Evidence is provided that sensitization of laboratory animals with pure SGGLs elicits experimental peripheral neuropathies that exhibit remarkable similarities with respect to antibody specificity, and electrophysiological and pathological features to the human conditions. By intraneural injection of antibodies into the sciatic nerve of rats, it is demonstrated that pathological changes consisting of demyelination and axonal degeneration are mediated by an antibody- and complement-dependent process. To elucidate the mechanisms of antibody penetration from circulation into the endoneurial space, it is further shown that brain microvascular endothelial cells express SGGLs. Moreover it has been found that inflammatory cytokines are capable of upregulating the expression of SGGLs on the endothelial cell surface, resulting in a greater attachment of leukocytes. This latter observation suggests that SGGLs may also participate in cell-mediated responses in certain inflammatory neurological disorders.