Antibodies to sulfated glycolipids in Guillain-Barré syndrome

Concurrent acute sensorimotor axonal neuropathy and disseminated encephalitis associated with Chlamydia pneumoniae in an adult patient with anti-MOG and anti-sulfatide antibodies: a case report

Acute disseminated encephalomyelitis and Guillain-Barré syndrome refer to post-infectious or post-vaccination inflammatory demyelinating disorders of central and peripheral nervous system, respectively. We report the case of a 60-year-old male patient presenting with irritability, gait difficulty, asymmetric quadriparesis (mostly in his left extremities), distal sensory loss for pain and temperature in left limbs, and reduced tendon reflexes in his upper limbs and absent in his lower limbs, following an upper respiratory tract infection, 3 weeks earlier. Brain magnetic resonance imaging revealed abnormal T2 signal and peripherally enhancing lesions in hemispheres, brainstem, and cerebellum. Nerve conduction studies were compatible with acute motor and sensory axonal neuropathy. Serology revealed positive IgM and IgG antibodies for Chlamydia pneumoniae, and he also tested positive for myelin oligodendrocyte glycoprotein (MOG) and sulfatide antibodies. Treatment with intravenous immunoglobulin and methylprednisolone led to clinical and radiological recovery within weeks. Even though several cases of combined central and peripheral demyelination have been reported before, it is the first case report with seropositive anti-sulfatide and anti-MOG acute sensorimotor axonal neuropathy and disseminated encephalitis associated with C. pneumoniae.

European Academy of Neurology/Peripheral Nerve Society Guideline on diagnosis and treatment of Guillain-Barré syndrome

Guillain-Barré syndrome (GBS) is an acute polyradiculoneuropathy. Symptoms may vary greatly in presentation and severity. Besides weakness and sensory disturbances, patients may have cranial nerve involvement, respiratory insufficiency, autonomic dysfunction and pain. To develop an evidence-based guideline for the diagnosis and treatment of GBS, using Grading of Recommendations, Assessment, Development and Evaluation (GRADE) methodology a Task Force (TF) of the European Academy of Neurology (EAN) and the Peripheral Nerve Society (PNS) constructed 14 Population/Intervention/Comparison/Outcome questions (PICOs) covering diagnosis, treatment and prognosis of GBS, which guided the literature search. Data were extracted and summarised in GRADE Summaries of Findings (for treatment PICOs) or Evidence Tables (for diagnostic and prognostic PICOs). Statements were prepared according to GRADE Evidence-to-Decision (EtD) frameworks. For the six intervention PICOs, evidence-based recommendations are made. For other PICOs, good practice points (GPPs) are formulated. For diagnosis, the principal GPPs are: GBS is more likely if there is a history of recent diarrhoea or respiratory infection; CSF examination is valuable, particularly when the diagnosis is less certain; electrodiagnostic testing is advised to support the diagnosis; testing for anti-ganglioside antibodies is of limited clinical value in most patients with typical motor-sensory GBS, but anti-GQ1b antibody testing should be considered when Miller Fisher syndrome (MFS) is suspected; nodal-paranodal antibodies should be tested when autoimmune nodopathy is suspected; MRI or ultrasound imaging should be considered in atypical cases; and changing the diagnosis to acute-onset chronic inflammatory demyelinating polyradiculoneuropathy (A-CIDP) should be considered if progression continues after 8 weeks from onset, which occurs in around 5% of patients initially diagnosed with GBS. For treatment, the TF recommends intravenous immunoglobulin (IVIg) 0.4 g/kg for 5 days, in patients within 2 weeks (GPP also within 2-4 weeks) after onset of weakness if unable to walk unaided, or a course of plasma exchange (PE) 12-15 L in four to five exchanges over 1-2 weeks, in patients within 4 weeks after onset of weakness if unable to walk unaided. The TF recommends against a second IVIg course in GBS patients with a poor prognosis; recommends against using oral corticosteroids, and weakly recommends against using IV corticosteroids; does not recommend PE followed immediately by IVIg; weakly recommends gabapentinoids, tricyclic antidepressants or carbamazepine for treatment of pain; does not recommend a specific treatment for fatigue. To estimate the prognosis of individual patients, the TF advises using the modified Erasmus GBS outcome score (mEGOS) to assess outcome, and the modified Erasmus GBS Respiratory Insufficiency Score (mEGRIS) to assess the risk of requiring artificial ventilation. Based on the PICOs, available literature and additional discussions, we provide flow charts to assist making clinical decisions on diagnosis, treatment and the need for intensive care unit admission.

European Academy of Neurology/Peripheral Nerve Society Guideline on diagnosis and treatment of Guillain-Barré syndrome

Guillain-Barré syndrome (GBS) is an acute polyradiculoneuropathy. Symptoms may vary greatly in presentation and severity. Besides weakness and sensory disturbances, patients may have cranial nerve involvement, respiratory insufficiency, autonomic dysfunction and pain. To develop an evidence-based guideline for the diagnosis and treatment of GBS, using Grading of Recommendations, Assessment, Development and Evaluation (GRADE) methodology, a Task Force (TF) of the European Academy of Neurology (EAN) and the Peripheral Nerve Society (PNS) constructed 14 Population/Intervention/Comparison/Outcome questions (PICOs) covering diagnosis, treatment and prognosis of GBS, which guided the literature search. Data were extracted and summarised in GRADE Summaries of Findings (for treatment PICOs) or Evidence Tables (for diagnostic and prognostic PICOs). Statements were prepared according to GRADE Evidence-to-Decision (EtD) frameworks. For the six intervention PICOs, evidence-based recommendations are made. For other PICOs, good practice points (GPPs) are formulated. For diagnosis, the principal GPPs are: GBS is more likely if there is a history of recent diarrhoea or respiratory infection; CSF examination is valuable, particularly when the diagnosis is less certain; electrodiagnostic testing is advised to support the diagnosis; testing for anti-ganglioside antibodies is of limited clinical value in most patients with typical motor-sensory GBS, but anti-GQ1b antibody testing should be considered when Miller Fisher syndrome (MFS) is suspected; nodal-paranodal antibodies should be tested when autoimmune nodopathy is suspected; MRI or ultrasound imaging should be considered in atypical cases; and changing the diagnosis to acute-onset chronic inflammatory demyelinating polyradiculoneuropathy (A-CIDP) should be considered if progression continues after 8 weeks from onset, which occurs in around 5% of patients initially diagnosed with GBS. For treatment, the TF recommends intravenous immunoglobulin (IVIg) 0.4 g/kg for 5 days, in patients within 2 weeks (GPP also within 2-4 weeks) after onset of weakness if unable to walk unaided, or a course of plasma exchange (PE) 12-15 L in four to five exchanges over 1-2 weeks, in patients within 4 weeks after onset of weakness if unable to walk unaided. The TF recommends against a second IVIg course in GBS patients with a poor prognosis; recommends against using oral corticosteroids, and weakly recommends against using IV corticosteroids; does not recommend PE followed immediately by IVIg; weakly recommends gabapentinoids, tricyclic antidepressants or carbamazepine for treatment of pain; does not recommend a specific treatment for fatigue. To estimate the prognosis of individual patients, the TF advises using the modified Erasmus GBS outcome score (mEGOS) to assess outcome, and the modified Erasmus GBS Respiratory Insufficiency Score (mEGRIS) to assess the risk of requiring artificial ventilation. Based on the PICOs, available literature and additional discussions, we provide flow charts to assist making clinical decisions on diagnosis, treatment and the need for intensive care unit admission.

Anti-Glycolipid Antibody Examination in Five EAE Models and Theiler's Virus Model of Multiple Sclerosis: Detection of Anti-GM1, GM3, GM4, and Sulfatide Antibodies in Relapsing-Remitting EAE

Anti-glycolipid antibodies have been reported to play pathogenic roles in peripheral inflammatory neuropathies, such as Guillain-Barré syndrome. On the other hand, the role in multiple sclerosis (MS), inflammatory demyelinating disease in the central nervous system (CNS), is largely unknown, although the presence of anti-glycolipid antibodies was reported to differ among MS patients with relapsing-remitting (RR), primary progressive (PP), and secondary progressive (SP) disease courses. We investigated whether the induction of anti-glycolipid antibodies could differ among experimental MS models with distinct clinical courses, depending on induction methods. Using three mouse strains, SJL/J, C57BL/6, and A.SW mice, we induced five distinct experimental autoimmune encephalomyelitis (EAE) models with myelin oligodendrocyte glycoprotein (MOG)35-55, MOG92-106, or myelin proteolipid protein (PLP)139-151, with or without an additional adjuvant curdlan injection. We also induced a viral model of MS, using Theiler's murine encephalomyelitis virus (TMEV). Each MS model had an RR, SP, PP, hyperacute, or chronic clinical course. Using the sera from the MS models, we quantified antibodies against 11 glycolipids: GM1, GM2, GM3, GM4, GD3, galactocerebroside, GD1a, GD1b, GT1b, GQ1b, and sulfatide. Among the MS models, we detected significant increases in four anti-glycolipid antibodies, GM1, GM3, GM4, and sulfatide, in PLP139-151-induced EAE with an RR disease course. We also tested cellular immune responses to the glycolipids and found CD1d-independent lymphoproliferative responses only to sulfatide with decreased interleukin (IL)-10 production. Although these results implied that anti-glycolipid antibodies might play a role in remissions or relapses in RR-EAE, their functional roles need to be determined by mechanistic experiments, such as injections of monoclonal anti-glycolipid antibodies.

A Severe Pharyngeal-Sensory-Ataxic Variant of Guillain-Barré Syndrome With Transient Cardiac Dysfunction and a Positive Anti-sulfatide IgM

Guillain-Barré syndrome (GBS) is a heterogeneous group of acute immune-mediated polyradiculoneuropathy that typically presents with classic axonal or demyelinating sensory-motor type. However, there are variants of GBS with atypical presentation. We report a rare case of severe pharyngeal-sensory-ataxic variant of GBS associated with poor cardiac systolic function, elevated troponin, and positive anti-sulfatide IgM. The sensory symptom atypically started in the hands in an ascending pattern, which progressed to involve the trunk and face and, later, all limbs. It was associated with severe dysphagia, ataxia, and generalized areflexia but with preserved muscle strength in all extremities. Recognizing the atypical pattern of presentation and the ability to perform an accurate clinical localization are the utmost important initial steps in making the diagnosis. The patient showed complete recovery after immunoglobulin therapy.

Innate immune suppression by SARS-CoV-2 mRNA vaccinations: The role of G-quadruplexes, exosomes, and MicroRNAs

The mRNA SARS-CoV-2 vaccines were brought to market in response to the public health crises of Covid-19. The utilization of mRNA vaccines in the context of infectious disease has no precedent. The many alterations in the vaccine mRNA hide the mRNA from cellular defenses and promote a longer biological half-life and high production of spike protein. However, the immune response to the vaccine is very different from that to a SARS-CoV-2 infection. In this paper, we present evidence that vaccination induces a profound impairment in type I interferon signaling, which has diverse adverse consequences to human health. Immune cells that have taken up the vaccine nanoparticles release into circulation large numbers of exosomes containing spike protein along with critical microRNAs that induce a signaling response in recipient cells at distant sites. We also identify potential profound disturbances in regulatory control of protein synthesis and cancer surveillance. These disturbances potentially have a causal link to neurodegenerative disease, myocarditis, immune thrombocytopenia, Bell's palsy, liver disease, impaired adaptive immunity, impaired DNA damage response and tumorigenesis. We show evidence from the VAERS database supporting our hypothesis. We believe a comprehensive risk/benefit assessment of the mRNA vaccines questions them as positive contributors to public health.

Differential binding patterns of anti-sulfatide antibodies to glial membranes

Sulfatide is a major glycosphingolipid in myelin and a target for autoantibodies in autoimmune neuropathies. However neuropathy disease models have not been widely established, in part because currently available monoclonal antibodies to sulfatide may not represent the diversity of anti-sulfatide antibody binding patterns found in neuropathy patients. We sought to address this issue by generating and characterising a panel of new anti-sulfatide monoclonal antibodies. These antibodies have sulfatide reactivity distinct from existing antibodies in assays and in binding to peripheral nerve tissues and can be used to provide insights into the pathophysiological roles of anti-sulfatide antibodies in demyelinating neuropathies.

Anti-sulfatide reactivity in patients with celiac disease

OBJECTIVE

To explore a possible significance of the presence of anti-ganglioside and anti-sulfatide antibodies in sera of adult patients with celiac disease (CD) in different clinical scenario.

METHODS

We selected 22 adult patients with newly diagnosed CD and 20 age-sex matched non-CD controls. Patients' serum was tested - before and after at least 6 months on a gluten-free diet (GFD) - for anti-GM1, GM2, GM3, GD1a, GD1b, GD3, GT1a, GT1b, GQ1b and sulfatide IgM, IgG and IgA auto-antibodies, by means of a dot blot technique and enzyme-linked immunosorbent assay (ELISA).

RESULTS

We found the presence of auto-antibodies in untreated patients. In particular, anti-sulfatide IgG antibodies were present in 8 (36%) patients independently of the presence of neurological symptoms. Anti-sulfatide IgA antibodies were present in 3 (19%) patients. During GFD, anti-sulfatide IgG disappeared in all the patients, whereas IgA were observed in 2 patients. Anti-sulfatide, anti-GM1 and anti-GM2 IgM antibodies were also observed in 2 patients on a GFD. All the other auto-antibodies were absent and no demographic or clinical parameters were associated. Non-CD controls did not present any auto-antibody.

CONCLUSIONS

We found anti-sulfatide IgG antibodies in CD patients on a gluten-containing diet. Anti-sulfatide IgA antibodies persisted during GFD together with the occurrence of other IgM auto-antibodies. These data suggest a possible link between gluten and IgG auto-antibodies.

Elevated anti-sulfatide antibodies in Guillain-Barré syndrome in T cell depleted at end-stage AIDS

A 38-year-old man developed the Guillain-Barré syndrome (GBS) associated with untreated end-stage AIDS and CD4+ lymphocyte count of 3 cells/mm(3). The patient had serum high titer anti-sulfatide antibodies and responded well to infusion of immunoglobulin. The data suggest that elevated levels of anti-sulfatide antibodies may play a role in the pathogenesis of GBS in this patient, although a direct neurotropic effect of HIV virus cannot be excluded.

Pathogenesis of chronic inflammatory demyelinating polyradiculoneuropathy

The acute lesions of chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) consist of endoneurial foci of chemokine and chemokine receptor expression and T cell and macrophage activation. The myelin protein antigens, P2, P0, and PMP22, each induce experimental autoimmune neuritis in rodent models and might be autoantigens in CIDP. The strongest evidence incriminates P0, to which antibodies have been found in 20% of cases. Failure of regulatory T-cell mechanism is thought to underlie persistent or recurrent disease, differentiating CIDP from the acute inflammatory demyelinating polyradiculoneuropathy form of Guillain-Barré syndrome. Corticosteroids, intravenous immunoglobulin and plasma exchange each provide short term benefit but the possible long-term benefits of immunosuppressive drugs have yet to be confirmed in randomised, controlled trials.

Developments in the prediction of type 1 diabetes mellitus, with special reference to insulin autoantibodies

The prodromal phase of type 1 diabetes is characterised by the appearance of multiple islet-cell related autoantibodies (Aab). The major target antigens are islet-cell antigen, glutamic acid decarboxylase (GAD), protein-tyrosine phosphatase-2 (IA-2) and insulin. Insulin autoantibodies (IAA), in contrast to the other autoimmune markers, are the only beta-cell specific antibodies. There is general consensus that the presence of multiple Aab (> or = 3) is associated with a high risk of developing diabetes, where the presence of a single islet-cell-related Aab has usually a low predictive value. The most commonly used assay format for the detection of Aab to GAD, IA-2 and insulin is the fluid-phase radiobinding assay. The RBA does not identify or measure Aab, but merely detects its presence. However, on the basis of molecular studies, disease-specific constructs of GAD and IA-2 have been employed leading to somewhat improved sensitivity and specificity of the RBA. Serological studies have shown epitope restriction of IAA that can differentiate diabetes-related from unrelated IAA, but current assays do not distinguish between disease-predictive and non-predictive IAA or between IAA and insulin antibodies (IA). More recently, phage display technology has been successful in identifying disease-specific anti-idiotopes of insulin. In addition, phage display has facilitated the in vitro production of antibodies with high affinity. Identification of disease-specific anti-idiotopes of insulin should enable the production of a high affinity reagent against the same anti-idiotope. Such a development would form the basis of a disease-specific radioimmunoassay able to identify and measure particular idiotypes, rather than merely detect and titrate IAA.

Antiglycolipid antibodies in Guillain-Barré syndrome and related diseases: Review of clinical features and antibody specificities

Guillain-Barré syndrome (GBS) is an acute inflammatory polyradiculoneuropathy that usually develops following a respiratory or intestinal infection. Although the pathogenic mechanisms of GBS have not been fully established, both humoral and cell-mediated immune factors have been shown to contribute to the disease process. Several antiglycosphingolipid (anti-GSL) antibodies have been found in the sera of patients with GBS or related diseases. Measurements of these antibody titers are very important in the diagnosis of GBS and in evaluating the effectiveness of treatments in clinical trials. The most common treatment strategies for these disorders involve plasmapheresis and the use of steroids for reducing anti-GSL antibody titers to ameliorate patients' clinical symptoms. Administration of intravenous immunoglobulin may also be beneficial in the treatment of neuropathies by suppressing the immune-mediated processes that are directed against antigenic targets in myelin and axons. In certain demyelinating neuropathies, the destruction or malfunctioning of the blood-nerve barrier, which results in the leakage of circulating antibodies into the peripheral nerve parenchyma, has been considered to be an initial step in development of the disease process. In addition, anti-GSL antibodies, such as anti-GM1, may cause nerve dysfunction and injury by interfering with the ion channel function at the nodes of Ranvier, where carbohydrate epitopes of glycoconjugates are located. These malfunctions thus contribute to the pathogenic mechanisms of certain demyelinating neuropathies.

Isolated cranial neuropathy associated with anti-glycolipid antibodies

We describe seven patients with isolated cranial neuropathy in whom serum anti-glycolipid antibodies were detected. Trigeminal sensory neuropathy was found in four patients, who had exhibited symptoms for 2 months to 4 years. The other three patients showed facial nerve palsy with or without ophthalmoparesis. Temporal profile analysis of anti-glycolipid antibodies revealed that titers of anti-glycolipid IgM antibodies against GM2 and LM1 gradually decreased in patients having chronic trigeminal sensory neuropathy. In patients with acute trigeminal sensory neuropathy, elevation of anti-LM1 antibody titers continued over 12 months although anti-GalNAc-GD1a antibody disappeared. On the other hand, titers of anti-glycolipid antibodies rapidly decreased in patients with acute facial nerve palsy with or without ophthalmoparesis. We conclude that anti-glycolipid antibodies may play an important role in the development of isolated cranial neuropathy in some patients.

Generation and characterization of antibodies to sulfated glucuronyl glycolipids in Lewis rats

Antibodies to sulfated glucuronyl glycolipids (SGGLs) have been reported in sera of patients with peripheral neuropathies including patients with IgM gammopathy. However, the role of anti-SGGL antibodies in the pathogenesis of neuropathy remains unclear. In order to study the role of antibodies to SGGLs in the pathogenesis of neuropathy, Lewis female rats were injected with purified SGPG mixed with keyhole limpet hemocyanin (KLH) and emulsified with equal amount of complete Freund's adjuvant. High titer anti-SGPG antibodies were detected by ELISA in sera of all rats inoculated with SGPG. All anti-SGPG antibodies cross-reacted with human myelin-associated glycoprotein (MAG). None of the sensitized rats exhibited clinical signs of neuropathy. Histological examination showed that there was no demyelination or axonal damage in peripheral nerves. Our data demonstrate that SGPG is a highly immunogenic glycolipid but high titer antibodies against it do not produce an experimental autoimmune neuropathy in Lewis rats.

Temporal profile of anti-ganglioside antibodies and their relation to clinical parameters and treatment in Guillain-Barré syndrome

Elevated anti-ganglioside antibody levels mainly of anti-GM1 and anti-GD1a specificities have been reported in THE serum of patients with Guillain-Barré syndrome (GBS). The relevance of anti-ganglioside antibodies other than anti-GM1 and anti-GD1a IgG antibodies and the temporal profile of anti-ganglioside antibodies in GBS is less clear. We studied serum antibodies to GM1, GD1a, GD1b, GQ1b, sulfatide and cardiolipin of the IgM, IgG and IgA classes over the course of GBS in patients who were untreated or treated with high dose intravenous immunoglobulin (IvIg). Antibodies to GD1b, GQ1b, sulfatide and cardiolipin were not detected in the sera of the GBS patients examined in this study. Anti-GM1 IgG titers peaked around 40 days and anti-GD1a IgM around 90 days after GBS onset. Titers of anti-GM1 IgG antibodies decreased following IvIg treatment. Patients with antibody peaks, defined as fivefold or higher increase in antibody titer compared to the lowest antibody titer over the course of GBS, had higher disability scores during the first two weeks of GBS and a worse clinical outcome (anti-GM1 IgG and anti-GD1a IgM antibody peaks) and axonal damage (anti-GD1a IgM antibody peaks), compared to patients without peak antibody titers. Anti-GM1 IgG and anti-GD1a IgM antibodies are thus strongly associated with more severe- and predominantly axonal cases of GBS. The appearance of anti-GM1 IgG and anti-GD1a antibody peaks in the serum after the termination of the acute phase of GBS suggests that these antibodies are produced secondary to nerve damage in GBS. The data does not exclude the possibility that secondarily secreted anti-GM1 IgG and anti-GD1a IgM antibodies may themselves be biologically active and play a role in disease propagation and/or recovery from disease in some patients with GBS.

Anti-sulfatide IgM antibodies in peripheral neuropathy

Anti-sulfatide IgM antibodies have been recently associated with neuropathy but the clinical and electrophysiological correlations of this reactivity remains unclear. We reviewed the clinical and electrophysiological features of patients with high anti-sulfatide titers detected in our laboratory from 1991 to 1998. Of the 564 patients with different neurological diagnosis tested by enzyme-linked immunosorbent assay (ELISA), 11 had high anti-sulfatide IgM titers (>1/8000), 26 had titers of 1/8000 while 78 had titers of 1/4000. All patients with high anti-sulfatide IgM titers had a chronic, dysimmune, mostly sensorimotor neuropathy that in seven was associated with IgM monoclonal gammopathy. In most of these patients electrophysiological and morphological studies were consistent with a predominantly demyelinating neuropathy frequently associated with prominent axonal loss. Antibody titers of 1/8000, though always associated with neuropathy, did not correlate with a particular form or cause of neuropathy, while lower titers were equally distributed in patients with different neurological disorders. Our study indicate that high anti-sulfatide IgM titers (>1/8000) are highly predictive for a chronic, dysimmune, mostly demyelinating neuropathy often associated with IgM monoclonal gammopathy, and may therefore have potential diagnostic relevance.

Pathogenesis of Guillain-Barré syndrome

Recent neurophysiological and pathological studies have led to a reclassification of the diseases that underlie Guillain-Barré syndrome (GBS) into acute inflammatory demyelinating polyradiculoneuropathy (AIDP), acute motor and sensory axonal neuropathy (AMSAN) and acute motor axonal neuropathy (AMAN). The Fisher syndrome of ophthalmoplegia, ataxia and areflexia is the most striking of several related conditions. Significant antecedent events include Campylobacter jejuni (4-66%), cytomegalovirus (5-15%), Epstein-Barr virus (2-10%), and Mycoplasma pneumoniae (1-5%) infections. These infections are not uniquely associated with any clinical subtype but severe axonal degeneration is more common following C. jejuni and severe sensory impairment following cytomegalovirus. Strong evidence supports an important role for antibodies to gangliosides in pathogenesis. In particular antibodies to ganglioside GM1 are present in 14-50% of patients with GBS, and are more common in cases with severe axonal degeneration associated with any subtype. Antibodies to ganglioside GQ1b are very closely associated with Fisher syndrome, its formes frustes and related syndromes. Ganglioside-like epitopes exist in the bacterial wall of C. jejuni. Infection by this and other organisms triggers an antibody response in patients with GBS but not in those with uncomplicated enteritis. The development of GBS is likely to be a consequence of special properties of the infecting organism, since some strains such as Penner 0:19 and 0:41 are particularly associated with GBS but not with enteritis. It is also likely to be a consequence of the immunogenetic background of the patient since few patients develop GBS after infection even with one of these strains. Attempts to match the subtypes of GBS to the fine specificity of anti-ganglioside antibodies and to functional effects in experimental models continue but have not yet fully explained the pathogenesis. T cells are also involved in the pathogenesis of most or perhaps all forms of GBS. T cell responses to any of three myelin proteins, P2, PO and PMP22, are sufficient to induce experimental autoimmune neuritis. Activated T cells are present in the circulation in the acute stage, up-regulate matrix metalloproteinases, cross the blood-nerve barrier and encounter their cognate antigens. Identification of the specificity of these T cell responses is still at a preliminary stage. The invasion of intact myelin sheaths by activated macrophages is difficult to explain according to a purely T cell mediated mechanism. The different patterns of GBS are probably due to the diverse interplay between antibodies and T cells of differing specificities.

Advances in chronic inflammatory demyelinating polyneuropathy: disease variants and inflammatory response mediators and modifiers

Available data on the immunopathogenesis of chronic inflammatory demyelinating polyneuropathy remain still fragmentary and insufficient for a unified hypothesis. Macrophage-mediated demyelination appears to play a fundamental role and cytokines, especially tumour necrosis factor-alpha, participate in this process. The nature of antigen presenting cells, T-cell receptors, adhesion molecules between inflammatory cells and myelinated fibers and the apparent predominance of T helper cell 1-related cytokines need to be explored to design more specific immunotherapies. In chronic cases of chronic inflammatory demyelinating polyneuropathy, a concomitant axonal loss secondary to primary demyelination is common and should be taken into consideration in the design of future therapeutic strategies.

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.

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.

Cyclosporin A in resistant chronic inflammatory demyelinating polyradiculoneuropathy

The role of cyclosporin A (CsA) in the treatment of resistant chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) was retrospectively reviewed in 19 patients who had failed to respond adequately to corticosteroids, plasmapheresis, intravenous immunoglobulin, and in some cases other immunosuppressive agents. Patients were subdivided into progressive or relapsing types according to the course of disease and response to therapy graded at follow-up by clinical and electrophysiological criteria. In the progressive group, the mean disability status declined from 3.8+/-0.7 to 1.8+/-1.1 grades on a 5-grade scale following CsA therapy (P<0.001). In the relapsing group, the mean annual incidence of relapse declined from 1.0+/-0.5 to 0.2+/-0.4 after commencement of CsA (P<0.05). Dose-dependent, reversible nephrotoxicity was the most serious complication of therapy, and necessitated cessation of CsA in 2 patients. In conclusion, CsA is an efficacious and, with appropriate monitoring, safe therapy for patients with CIDP.

Antibodies to GT1a ganglioside in patients with Guillain-Barré syndrome

Serum antibodies from 8 (13%) of 62 patients with the acute Guillain-Barré syndrome (GBS) and 1 of 3 patients with the Miller Fisher syndrome (MFS) recognized a minor ganglioside in bovine and human brain trisialoganglioside fractions. The ganglioside antigen migrated between GD1a and GD1b on thin-layer chromatograms. The structure of this ganglioside was established to be GT1a by thin-layer chromatography blotting and mass spectrometry. GT1a a ganglioside was also detected in human and bovine peripheral nerves by thin-layer chromatogram immunostaining. Serum from the GBS patients had IgM, IgG, or IgA antibodies against GT1a detectable by enzyme-linked immunosorbent assay (ELISA). Serum from the MFS patient also had elevated levels of IG against GT1a. None of the sera from 43 patients with other neurological diseases or from 24 healthy controls reacted with GT1a. Sera from 6 of 8 GBS patients with anti-Gt1a antibodies also reacted with GQ1b. There was no difference in the incidence of anti-GT1a immunoglobulins in acute GBS patients with or without oculomotor abnormalities. Levels of anti-GT1a antibodies correlated temporally wit clinical symptoms in GBS patients. Although the incidence of dysphagia was slightly higher in GBS patients with anti-GT1a antibodies than in those without, the number of patients studied may have been too small to detect an association between anti-GT1a antibodies and an a specific clinical variant of GBS. Our data demonstrate that a proportion of GBS patients have antibodies against GT1a ganglioside and suggest that these antibodies may play a role in the pathogenesis of neuropathy in GBS.

Immunological investigation of chronic inflammatory demyelinating polyradiculoneuropathy

In order to investigate the hypothesis that chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is an autoimmune disease related to the acute inflammatory form of Guillain-Barre Syndrome (GBS), we studied 40 patients, 40 age and sex matched controls with other forms of peripheral neuropathy (ONP) and 37 controls from the same family or household (FC). We sought antibodies to gangliosides GM1 and LM1 by enzyme linked immunoassay (ELISA) confirmed by immuno-overlay. Only 6 (15%) CIDP patients had IgM antibodies to ganglioside GM1 (GM1) and none had IgG antibodies. We found IgM antibodies to ganglioside LM1 in 2 (5%) and IgG antibodies in 4 (10%) CIDP patients. Antibodies of IgG or IgM class were detected by ELISA to chondroitin sulphate C or sulfatide in up to 7.5% of CIDP patients. There were IgM antibodies in 3 (7.5%) and IgG in 4 (10%) patients against 25, 28 or 36 kD myelin proteins identified by immunoblot. Antibodies to any of these candidate myelin autoantigens were not significantly more frequent in CIDP than FC or ONP controls. Sera from 5 CIDP patients with active disease which subsequently responded to plasma exchange did not induce more demyelination upon intraneural injection into rat sciatic nerve than ONP sera. Serum tumor necrosis factor alpha (TNFalpha) concentrations were not increased in any of the CIDP patients. Serological evidence of Campylobacter jejuni (Cj) infection was present in 4 (10%) CIDP patients. IgM antibodies to cytomegalovirus (CMV) were not detected in any sera. CIDP is not commonly associated with either of these infections or with an antibody-mediated response to any of these glycolipid or myelin autoantigens.

Autoantibodies to peripheral nerve glycosphingolipids SPG, SLPG, and SGPG in Guillain-Barré syndrome and chronic inflammatory demyelinating polyneuropathy

Unlike CNS myelin, human peripheral nerve myelin has the acidic glycosphingolipids sialosyl paragloboside (SPG), sialosyl lactosaminyl paragloboside (SLPG), and sulfated glucuronyl paragloboside (SGPG). To elucidate the pathogenesis of Guillain-Barré syndrome (GBS) and chronic inflammatory demyelinating neuropathy (CIDP), we investigated the autoantibodies to peripheral nerve molecules in patients with these diseases and compared the frequency of the autoantibodies with that of autoantibody to GM1 which is present in both the CNS and PNS. The report of Sheikh et al. (Ann. Neurol. 1995; 38: 350) that Campylobacter jejuni bears the SGPG epitope led us to study whether sera from patients with GBS subsequent to C. jejuni enteritis have anti-SGPG antibody; but, high anti-SGPG antibody titers were not found in the GBS patients from whom C. jejuni was isolated. Although the frequency of the anti-SPG, anti-SLPG and anti-SGPG antibodies were lower than that of the anti-GM1 antibody in GBS, 5 patients with demyelinating GBS had high IgG anti-SPG antibody titers. IgG anti-SPG antibody may function in the development of demyelinating GBS. We found that 6 CIDP patients had elevated IgM anti-SGPG antibody titers. Immunoelectrophoresis failed to detect IgM M-protein in 3 of the patients. IgM anti-SGPG antibody could be a diagnostic marker for a subgroup of CIDP with or without paraprotein.

Anti-skeletal muscle glycolipid antibodies in human heart transplantation as markers of acute rejection. Correlation with endomyocardial biopsy

In seventeen patients the result of the histological study of 153 endomyocardial biopsies (EMB) was compared with the ELISA titer of anti-human skeletal muscle glycolipid antibodies (AGA) present in serum samples collected simultaneously with the EMB procedure during the first four months following cardiac transplantation. The glycolipids were extracted from the quadriceps femoralis of blood group O patients. In the serum samples corresponding to the histological rejection grades with myocyte necrosis (greater than or equal to 2, International Society for Heart and Lung Transplantation grading) the AGA titer was significantly higher (P<0.005) than in the less severe rejection grades. The follow-up in each patient showed that the AGA titer raised in the serum samples collected immediately after, before, or coincidentally with a histological diagnosis of rejection grade 2 or 3A. In only one rejection grade 3A case was a false-negative result observed. Determination of the cut-off of the AGA level versus rejection grades 2 and 3A was determined by a relative-operating characteristic curve. An optical density (OD) of 0.040 showed maximum efficiency with sensitivity 53% and specificity 79%. Four patients who had AGA with an OD above 0.040 at the time of transplant had a significantly higher number of rejection grade 2 and 3A episodes than eleven patients with low pre-transplant AGA titers (P<0.05). These results indicate that search of anti-skeletal muscle glycolipid antibodies may represent a useful noninvasive method for monitoring heart rejection, and suggest that its investigation prior transplant may be a predictor of the number of grades 2 and 3A rejection episodes.

Intrathecal synthesis of anti-sulfatide IgG is associated with peripheral nerve disease in acquired immunodeficiency syndrome

Peripheral nervous system involvement in the acquired immunodeficiency syndrome (AIDS) can take the form of an acute or chronic inflammatory demyelinating polyneuropathy, polyradiculopathy, mononeuropathy multiplex, or autonomic neuropathy. There is no widely held consensus on the etiology of PNS or other neurological complications associated with HIV infection. We report here that PNS disease in HIV-infected individuals is associated with intrathecal synthesis of an antibody directed against sulfatide, a major component of myelin. The anti-sulfatide antibody is also present nonspecifically in serum. The antibody requires the presence of the 3-O-sulfogalactosyl residue for binding and recognizes preferentially the hydroxy fatty acid-containing form of sulfatide. Anti-sulfatide antibodies are therefore one of the humoral factors responsible for demyelinating diseases in AIDS patients.

Systemic passive transfer studies using IgM monoclonal antibodies to sulfatide

We present a patient with benign IgM-gamma anti-Sulfatide (SUL) whose neuropathy was transferred in newborn rabbits. The patient's clinico-pathological picture of anti-SUL-associated demyelinating neuropathy is reported. The monoclonal IgM antibodies prepared by Tatum's method, that retained their biological activity, were passively transferred to newborn rabbits. The passive transfer produced demyelinating nerve lesions very similar to the donor antibody neuropathy. In experimental lesions we observed the human IgM anti-SUL antibodies binding to Schmidt-Lanterman incisures and nodes of Ranvier. We postulate that the myelin-specific and complement-dependent lesions observed in the peripheral nerve support the potential demyelinating role of anti-SUL antibodies. Moreover, the pattern of the antibody binding to the perineuronal sheath of satellite cells in dorsal root ganglia strengthen the hypothesis that anti-SUL antibodies may have a pathogenetic role in this sensorimotor syndrome.

Anti-GM1 IgG antibodies and Campylobacter bacteria in Guillain-Barré syndrome: evidence of molecular mimicry

In Guillain-Barré syndrome antibodies to GM1 and the presence of an antecedent Campylobacter jejuni infection are correlated with a more severe course of the disease. From a group of 137 consecutive GBS patients, 11 sera had elevated titers of anti-GM1 IgG antibodies during the acute stage of disease. Each serum sample was preincubated with three different Penner serotypes of whole C. jejuni (PEN O:4/59, PEN O:41) and Campylobacter coli (PEN O:22) bacteria. The PEN O:4/59 serotype, isolated from the stools of a Guillain-Barré syndrome patient, inhibited 63 to 93% of the anti-GM1 activity in 6 of 11 patients. The PEN O:41 inhibited 63 to 100% of the anti-GM1 antibody activity in 9 of 11 patients. The PEN O:22 inhibited anti-GM1 antibody activity in only 2 of 11 patients (80 and 86%). Two Guillain-Barré syndrome patients did not show antibody absorption by any of the Campylobacter serotypes tested, although this does not exclude the involvement of other serotypes. An Escherichia coli control strain did not significantly absorb anti-GM1 antibodies. The results of this study indicate that anti-GM1 IgG antibodies in Guillain-Barré syndrome sera recognize surface epitopes on whole Campylobacter bacteria and that this recognition is strain-specific. This provides evidence for molecular mimicry in the pathogenesis of Guillain-Barré syndrome.

Guillain-Barré syndrome and chronic inflammatory demyelinating polyneuropathy: immune mechanisms and update on current therapies

The relation between Guillain-Barré syndrome and chronic inflammatory demyelinating polyneuropathy is discussed. Most likely they represent parts of a continuum, arbitrarily separated by their time course. Within the concept of chronic inflammatory demyelinating polyneuropathy the presence of a monoclonal gammopathy of undetermined significance is discussed. The pathogenesis of inflammatory demyelinating polyneuropathies has not been elucidated yet, but involvement of the immune system has been firmly established. Preceding infections, especially with Campylobacter jejuni, and the analysis of antiganglioside antibodies lend new support to the hypothesis of molecular mimicry between epitopes on infectious agents and peripheral nerve constituents as one of the mechanisms in Guillain-Barré syndrome. In the future, a further classification of individual patients based on clinical, epidemiological, electrophysiological, pathological, microbiological, and immunological criteria may give a basis for more individualized treatment strategies. In Guillain-Barré syndrome the efficacy of high-dose intravenous immune globulin treatment was established after earlier positive findings with plasma exchange; immune globulins are easier to administer and may be superior. Even with these treatments it should be anticipated that one fourth of patients after immune globulin treatment and one third of patients after plasma exchange will show further deterioration in the first 2 weeks after onset of treatment. Despite this, just one treatment course usually is indicated in the individual patient, and no valid arguments were found to switch to the other treatment modality. In chronic inflammatory demyelinating polyneuropathy, prednisone, plasma exchange, and immune globulins are effective in a proportion of patients. The last two are equally effective. Patients may respond to one of these if a previous treatment failed, and here switching therapy may be effective due to the chronic course of the disease. Complexity and costs make plasma exchange the last choice. Whether prednisone or immune globulin is the first choice depends on the speed of recovery and the estimation of long-term loss of quality of life due to side effects of prednisone versus the costs of immune globulins. The mechanism of immune globulins in inflammatory polyneuropathies is discussed. There is evidence that idiotypic-antiidiotypic interaction may play a role, but several other mechanisms also may be involved.

Activated T cells of nonneural specificity open the blood-nerve barrier to circulating antibody

Recent studies from our laboratory and by other investigators have shown that autoreactive CD4+ cells specific for peripheral nerve P2 protein have a powerful effect on blood-nerve barrier permeability. In this study we injected CD4+ T cells reactive to a nonneural antigen (ovalbumin) systemically and achieved their accumulation in the tibial nerve of Lewis rats by previous intraneural injection of ovalbumin. Selected rats were given systemic demyelinating antibody (antigalactocerebroside) to provide an indicator of changes in the permeability of the blood-nerve barrier, and the animals were monitored by sequential neurophysiological studies and histology. Circulating ovalbumin-specific T cells accumulated at sites of intraneural ovalbumin injection without inducing demyelination in control animals. In rats with circulating galactocerebroside antibodies, local conduction block and demyelination were seen in the region of T-cell accumulation. Electron microscopy demonstrated dissolution of some tight junctions between endothelial cells in areas of T-cell accumulation, and T cells traversing the endothelium between endothelial cells and through their cytoplasm. Endothelial cell damage was evident in these areas. This study demonstrates breakdown of the blood-nerve barrier by activated T cells, even of nonneural specificity, allowing the development of focal conduction block and demyelination in the presence of circulating antimyelin antibodies.

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

The etiology of the Guillain-Barré syndrome (GBS) still remains elusive. Recent years have witnessed important advances in the delineation of the mechanisms that may operate to produce nerve damage. Evidence gathered from cell biology, immunology, and immunopathology studies in patients with GBS and animals with experimental autoimmune neuritis (EAN) indicate that GBS results from aberrant immune responses against components of peripheral nerve. Autoreactive T lymphocytes specific for the myelin antigens P0 and P2 and circulating antibodies to these antigens and various glycoproteins and glycolipids have been identified but their pathogenic role remains unclear. The multiplicity of these factors and the involvement of several antigen nonspecific proinflammatory mechanisms suggest that a complex interaction of immune pathways results in nerve damage. Data on disturbed humoral immunity with particular emphasis on glycolipid antibodies and on activation of autoreactive T lymphocytes and macrophages will be reviewed. Possible mechanisms underlying initiation of peripheral nerve-directed immune responses will be discussed with particular emphasis on the recently highlighted association with Campylobacter jejuni infection.

Myelin- and microbe-specific antibodies in Guillain-Barré syndrome

We surveyed the frequency of reported infections and target autoantigens in 56 Guillain Barré syndrome (GBS) patients by detecting antibodies to myelin and microbes. Sulfatide (43%), cardiolipin (48%), GD1a (15%), SGPG (11%), and GM3 (11%) antibodies were the most frequently detected heterogenous autoantibodies. A wide spectrum of antimicrobial IgG and IgM antibodies were also detected; mumps-specific IgG (66%), adenovirus-specific IgG (52%), varicella-zoster virus-specific IgG (46%), and S. pneumoniae serotype 7-specific IgG (45%) were the most prevalent. Our results indicate that polyclonal expansion of physiologic and pathologic antibodies and/or molecular mimicry likely occurs following infection and is related to other autoimmune factors in the etiology of GBS. Although no single definitive myelin-specific autoantibody was identified, our results suggest a unique pattern of reactivity against autoantigens.

Antiglycolipid antibodies in peripheral neuropathy: fact or fiction?

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Anti-glycosphingolipid autoantibodies in rheumatologic disorders

Antibodies directed against ganglioside GM1 or sulfatides are frequently associated with motor or sensorimotor neuropathies. To establish the prevalence of such anti-glycosphingolipid autoantibodies in autoimmune disorders and to determine whether they contribute to neurologic symptoms in those individuals, we measured these antibodies by enzyme-linked immunosorbent assay (ELISA) in serum samples from rheumatologic patients with and without peripheral neuropathies (PN). We tested 21 patients with systemic lupus erythematosus (9 with PN), 26 with Sjögren's syndrome (12 with PN), 34 with scleroderma (28 with PN), and 14 with rheumatoid arthritis (4 with PN). Samples from 32 normal individuals were also tested. Patients with systemic lupus erythematosus and rheumatoid arthritis had elevated concentrations of GM1 antibodies and scleroderma patients had lower levels of sulfatide antibodies compared to healthy individuals. The presence of ganglioside or sulfatide antibodies did not correlate with the development of peripheral neuropathy in these patients. These findings suggest that relatively low-titer glycosphingolipid antibodies may arise as part of a nonspecific polyclonal gammopathy in rheumatologic disorders but generally without clinical manifestation.

Anti-sulphatide antibodies in peripheral neuropathy

A study was carried out on 135 patients with chronic idiopathic neuropathy (63), neuropathy associated with monoclonal gammopathy (51, including eight with anti-MAG antibody activity) and the Guillain-Barré syndrome (GBS) (21). Serum IgM, IgG and IgA anti-sulphatide antibody titres were compared with titres in 304 patients with other neurological or immunological diseases and in 50 normal subjects. Titres were presented a) as the highest serum dilution at which reactivity could be detected, and b) in the linear region of the optical density curve. A substantial number of patients with neurological or immunological diseases had higher titres than normal subjects. Compared with normal and disease controls, five patients with neuropathy associated with IgMk monoclonal gammopathy had raised titres of IgM anti-sulphatide antibodies and one patient with GBS had raised IgM, IgG and IgA anti-sulphatide antibodies in the acute phase of the disease. Two patients had a predominantly axonal sensory neuropathy with presenting symptoms of painful paresthesiae and minimal neurological deficit. Three patients had a predominantly demyelinating sensorimotor neuropathy associated with anti-MAG antibody activity. The patient with GBS had extensive sensory loss and antibody titres returned to normal within three weeks. Raised titres of anti-sulphatide antibodies occurred in several types of neuropathy, but all had some degree of sensory impairment and associated immunological abnormality.

Antibody responses to P0 and P2 myelin proteins in Guillain-Barré syndrome and chronic idiopathic demyelinating polyradiculoneuropathy

Immunisation with the peripheral nerve myelin proteins P0 or P2 induces inflammatory neuropathy in animals. We sought antibodies with an ELISA to these proteins in 38 patients with acute Guillain-Barré syndrome (GBS), 32 patients with chronic idiopathic demyelinating polyradiculoneuropathy (CIDP), 31 patients with other neuropathies (ONP) and 26 normal control (NC) subjects. We discovered IgM antibodies to human P0 protein in the sera of 18.5% of the patients with GBS, 15.6% with CIDP, 6.4% with ONP and 3.8% of NC subjects. Of the sera which reacted with P0, sera from 4/7 of GBS, 3/5 of CIDP, 1/2 of ONP patients and 0/1 of NC subjects reacted with a synthetic P0 peptide representing residues 150-169 from the cytoplasmic portion of the molecule. IgG antibodies to P0 were slightly less common than IgM antibodies, being present in only 7.9% of GBS, 0% of CIDP and 3% of ONP patients and 0% of NC subjects. We found antibodies to bovine P2 protein more commonly than antibodies to P0. IgM antibodies were present in 39.5% of GBS, 34.4% of CIDP, 16.1% of ONP patients and 15.4% of NC subjects. IgG antibodies were present in 18.4% of GBS, 12.5% of CIDP, 3.2% of ONP patients and 7.6% of NCs. Of the sera which contained antibodies to P2 protein, only a few reacted with P2 peptides 14-25 or 58-81, but without any consistent pattern of reactivity.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of ganglioside administration on experimental autoimmune neuritis induced by peripheral nerve myelin or P2-specific T cell lines

We studied the effects of ganglioside administration in two animal models of inflammatory demyelinating polyneuropathy. We administered a mixture of bovine brain gangliosides intraperitoneally to Lewis rats with myelin-induced or T cell line-mediated experimental autoimmune neuritis (EAN). Under the experimental conditions we had chosen, we only detected marginal but not statistically significant effects on disease course and severity, as evidenced by motor function, electrophysiological findings, and morphological signs of inflammation and demyelination. There was no significant induction of antibody production against gangliosides, and we did not detect signs of increased cellular reactivity towards gangliosides. We conclude that the administration of gangliosides modulates EAN at best marginally, and does not induce a cellular or humoral immune reaction.

Effects of Guillain-Barré sera containing antibodies against glycolipids in cultures of rat Schwann cells and sensory neurons

Serum samples from 52 patients with the acute Guillain-Barré syndrome (GBS), 19 patients with other neurological disorders, and 18 healthy volunteers were tested for cytotoxicity in cultures of rat Schwann cells and dorsal root ganglion neurons. The samples were also examined by enzyme-linked immunosorbent assay for IgG and IgM antibodies against various acidic and neutral glycolipids. Samples from 16 of the 52 (31%) acute GBS patients and from 1 of the 6 patients with chronic inflammatory demyelinating polyneuropathy produced myelin breakdown in culture. Although 10 of the 16 cytotoxic acute GBS serum samples contained anti-glycolipid immunoglobulins, there was no correlation in individual samples between cytotoxic activity and the presence of antibodies against specific glycolipids. While our results do not exclude a role for anti-glycolipid antibodies in the pathogenesis of the acute GBS, the cytotoxic effects of acute GBS serum in cultures of Schwann cells and sensory neurons are probably not due to these antibodies alone.

Anti-sulfatide antibodies in neurological disease: binding to rat dorsal root ganglia neurons

Increased titers of anti-sulfatide antibodies were detected by ELISA in 5 of 200 patients and control subjects. All 5 patients had sensory impairment; 4 had neuropathy, and one had multiple sclerosis. Of the patients with neuropathy, 2 had a clinical syndrome of small fiber sensory neuropathy with normal electrophysiological or nerve biopsy studies, 1 had a sensorimotor axonal neuropathy associated with IgM monoclonal gammopathy, and 1 had sensorimotor neuropathy with multifocal motor conduction block and anti-GM1 antibodies. The anti-sulfatide antibodies bound to the surface of unfixed rat dorsal root ganglia neurons and human neuroblastoma cells, and to fixed sections of central and peripheral myelin. No binding was detected following intraneural injection into rat sciatic nerves. Pre-absorption with sulfatide but not with galactocerebroside eliminated the tissue binding activity. These findings indicate that increased titers of anti-sulfatide antibodies are found in patients with sensory impairment but are not restricted to a particular neurological syndrome or type of neuropathy. The significance of anti-sulfatide antibodies is uncertain although sulfatide on dorsal root ganglia neurons may be a target antigen.