Anti-GQ1b antibodies and evoked acetylcholine release at mouse motor endplates

Miller Fisher syndrome (MFS) is clinically characterized by ataxia, areflexia, and ophthalmoplegia, and is associated with serum anti-GQ1b-ganglioside antibodies. We have previously shown that anti-GQ1b antibodies induce complement-dependent, alpha-latrotoxin-like effects at mouse neuromuscular junctions (NMJs) in vitro. This effect comprises a massive increase in spontaneous quantal acetylcholine (ACh) release, accompanied by block of evoked release and muscle paralysis. This mechanism may contribute to the motor features of MFS. Whether the block of evoked ACh release is a primary effect of anti-GQ1b antibodies or occurs secondary to massive complement-dependent spontaneous release is unknown. Using conventional micro-electrode methods, we measured in detail ACh release evoked with low- and high-rate nerve stimulation, and studied the effect on it of a purified MFS IgG and a mouse monoclonal anti-GQ1b IgM (without added complement). We found that evoked transmitter release was unaffected. Control experiments proved binding of anti-GQ1b antibody at the NMJ. We conclude that the block of nerve-evoked ACh release at the NMJ is not a primary effect of anti-GQ1b antibodies, but is dependent on antibody-mediated complement activation. It remains to be determined whether the block of nerve-evoked ACh release is the consequence of massive spontaneous ACh release or occurs as a concomitant event.     

Miller Fisher anti-GQ1b antibodies: α-Latrotoxin–like effects on motor end plates

In the Miller Fisher syndrome (MFS) variant of the Guillain-Barré syndrome, weakness is restricted to extraocular muscles and occasionally other craniobulbar muscles. Most MFS patients have serum antibodies against ganglioside type GQ1b of which the pathophysiological relevance is unclear. We examined the in vitro effects of MFS sera, MFS IgG, and a human monoclonal anti-GQ1b IgM antibody on mouse neuromuscular junctions (NMJs). It was found that anti-GQ1b antibodies bind at NMJs where they induce massive quantal release of acetylcholine from nerve terminals and eventually block neuromuscular transmission. This effect closely resembled the effect of the paralytic neurotoxin α-latrotoxin at the mouse NMJs, implying possible involvement of α-latrotoxin receptors or associated downstream pathways. By using complement-deficient sera, the effect of anti-GQ1b antibodies on NMJs was shown to be entirely dependent on activation of complement components. However, neither classical pathway activation nor the formation of membrane attack complex was required, indicating the effects could be due to involvement of the alternative pathway and intermediate complement cascade products. Our findings strongly suggest that anti-GQ1b antibodies in conjunction with activated complement components are the principal pathophysiological mediators of motor symptoms in MFS and that the NMJ is an important site of their action. Ann Neurol 1999;45:189–199     

Recent developments in Miller Fisher syndrome and related disorders

PURPOSE OF REVIEW: Miller Fisher syndrome is a localized variant of Guillain-Barré syndrome, characterized by ophthalmoplegia, areflexia and ataxia. Bickerstaff's brainstem encephalitis is a related syndrome in which upper motor neurone features accompany the classic triad. Anti-GQ1b antibodies are uniquely found in both conditions and are believed to be pathogenic. RECENT FINDINGS: Infectious illnesses usually precede Miller Fisher syndrome. The clearest associations have been described with Haemophilus influenzae and Campylobacter jejuni infection. Raised cerebrospinal fluid protein is seen in 60% of patients, but clinical features and anti-GQ1b antibody testing are diagnostically more informative. Experimental studies demonstrating complement-dependent neuromuscular block may be relevant to the clinical pathophysiology of Miller Fisher syndrome. Recent neurophysiological studies suggest abnormal neuromuscular transmission occurs in some cases of Miller Fisher syndrome and Guillain-Barré syndrome. Recent mouse models have demonstrated that presynaptic neuronal membranes and perisynaptic Schwann cells are targets for anti-GQ1b antibody attack. The elimination of antiganglioside antibodies from the circulation through specific immunoadsorption therapy has the potential to ameliorate the course of Miller Fisher syndrome. This condition is typically a benign, self-limiting illness. Both plasmapheresis and intravenous immunoglobulin may be employed as treatment, especially in cases of Bickerstaff's brainstem encephalitis or those with overlapping Guillain-Barré syndrome. SUMMARY: Anti-GQ1b antibody testing has allowed clinicians to develop a greater understanding of the spectrum of Miller Fisher syndromes and to refine clinical diagnoses in patients with unusual presentations. Experimental studies strongly suggest anti-GQ1b antibodies are pathogenic, which in principle should direct treatments towards antibody neutralization or elimination.     

Complement inhibition abrogates nerve terminal injury in Miller Fisher syndrome

A large body of clinical and experimental data indicate that complement activation is an important mechanism for neuronal and glial injury in Guillain-Barré syndromes. Inhibition of complement activation therefore might be expected to limit the progression of the disease. Using in vitro and in vivo models of the Guillain-Barré syndrome variant, Miller Fisher syndrome, we have shown previously that anti-GQ1b ganglioside antibodies target the presynaptic motor nerve terminal axon and surrounding perisynaptic Schwann cells, thereby mediating destructive injury through deposition of membrane attack complex. Here, we have used this model to investigate the effects of a novel therapeutic inhibitor of complement activation, APT070 (Mirococept), both in vitro and in vivo. In these models, APT070 completely prevents membrane attack complex formation, and thereby has a major neuroprotective effect at the nerve terminal, as assessed by immunohistology of perisynaptic Schwann cell and axonal integrity. These data provide a rationale for considering clinical trials of APT070 in Guillain-Barré syndrome, its variant forms, and other complement dependent neuromuscular disorders.     

C5 inhibitor rEV576 protects against neural injury in an in vitro mouse model of Miller Fisher syndrome

Guillain-Barré syndrome and its clinical variants, including the anti-GQ1b ganglioside-mediated Miller Fisher syndrome (MFS), comprise the world's leading cause of acute neuromuscular paralysis. Presently, no specific drug therapies exist. The complement cascade, which is activated in these patients, forms an attractive drug target. In this study, we tested whether the complement C5-inhibiting recombinant protein, rEV576, was able to prevent neural injury in a previously developed in vitro mouse model for MFS. Mouse hemidiaphragm preparations were treated with anti-GQ1b antibody and normal human serum as a source of complement with added rEV576 or control protein. Immunohistology in control tissue showed deposition of C3c and membrane attack complex at neuromuscular junctions (NMJs), along with terminal motor axonal neurofilament degradation as well as ethidium homodimer-2 staining showing perisynaptic Schwann cell (pSC) injury. Electrophysiological and functional analyses showed block of synaptic transmission at the NMJ after an initial period of a dramatically high level of asynchronous acetylcholine release. In tissue treated with rEV576, all these indicators of motor neuronal damage were absent, except for the presence of C3c, indicating effective inhibition of C5. These results demonstrate that rEV576 effectively prevents development of neuronal and pSC damage in experimental murine neuropathy.     

Detection and prevalence of alpha-latrotoxin-like effects of serum from patients with Guillain-Barré syndrome

Anti-GQ1b antibodies are associated with the Miller Fisher syndrome (MFS), a variant of the Guillain-Barré syndrome (GBS). In the ex vivo mouse diaphragm, anti-GQ1b-positive MFS serum induces muscle fiber twitching, a temporary dramatic increase of spontaneous quantal acetylcholine release, and transmission blockade at neuromuscular junctions (NMJs). These effects resemble those of alpha-latrotoxin (alpha-LTx) and are induced by antibody-mediated activation of complement. We developed an assay for detection of the alpha-LTx-like effect, using muscle fiber twitching as indicator. We tested 89 serum samples from GBS, MFS, and control subjects, and studied correlations with clinical signs, anti-ganglioside antibodies, micro-electrode physiology, and complement deposition at NMJs. Twitching was observed with 76% of the MFS and 10% of the GBS samples. It was associated with ophthalmoplegia and anti-GQ1b antibodies in patients, and with increased spontaneous acetylcholine release and C3c-deposition at mouse NMJs. This study strongly suggests that antibodies to GQ1b (with cross-reactivity to related gangliosides) are responsible for the alpha-LTx-like activity. The twitching assay is an efficient test for detection of this effect, and allows for screening of large numbers of samples and modifying drugs.     

Combined pre- and postsynaptic action of IgG antibodies in Miller Fisher syndrome

BACKGROUND: Miller Fisher syndrome (MFS), a variant of the Guillain-Barré syndrome, is associated with the presence of neuromuscular blocking antibodies, some of which may be directed at the ganglioside GQ1b. MATERIALS AND METHODS: The authors investigated the in vitro effects of serum and purified immunoglobulin (Ig) G in a total of 11 patients with typical MFS during active disease, and in three of those patients after recovery. From one patient's serum, we prepared an IgG fraction enriched in anti-GQ1b antibodies by affinity chromatography. For combined pre- and postsynaptic analysis, endplate currents were recorded by a perfused macro-patch clamp electrode. Postsynaptic nicotinic acetylcholine receptor channels were investigated by an outside-out patch clamp technique in cultured mouse myotubes. RESULTS: AllMFS-sera depressed evoked quantal release and reduced the amplitude of postsynaptic currents. Five of the 11 sera were additionally examined by outside-out patch clamp analysis and caused a concentration-dependent and reversible decrease in acetylcholine-induced currents. The time course of activation and desensitization of nicotinic acetylcholine receptor channels was not altered by MFS-IgG. Nine patients (82 %) were positive for anti-GQ1b antibodies in ELISA and dot-blot. The enriched anti-GQ1b antibody fraction had a similar effect as whole serum. After recovery from MFS, blocking activity was lost and sera originally positive for anti-GQ1b antibodies became negative. CONCLUSION: Circulating IgG antibodies induce both pre- and postsynaptic blockade and may play a pathogenic role in acute MFS.     

Acute oropharyngeal palsy is associated with antibodies to GQ1b and GT1a gangliosides.

Three patients with acute oropharyngeal palsy had high titre anti-GQ1b and anti-GT1a IgG antibodies. No patients had ophthalmoplegia or ptosis. In all patients limb ataxia or areflexia were present without notable limb weakness. These patients describe an oropharyngeal variant of Guillain-Barré syndrome in terms of anti-GQ1b antibody reactivity and show that high titre anti-GQ1b antibodies, serologically indistinguishable from those found in Miller Fisher syndrome, can occur in a clinical setting without ophthalmoplegia. The anti-GQ1b and anti-GT1a antibody assays may be helpful tests when considering the differential diagnosis of acute oropharyngeal palsy.     

IgM anti-GQ1b monoclonal antibody inhibits voltage-dependent calcium current in cerebellar granule cells

Miller–Fisher syndrome (MFS), which is known to be associated with anti-GQ1b antibodies and to cause ataxia, is a variant of an acute inflammatory neuropathy. However, the pathogenic role of anti-GQ1b antibodies remains unclear. In this study, we investigated the effects of mouse IgM anti-GQ1b monoclonal antibody (IgM anti-GQ1b mAb) on the spontaneous muscle action potential of a rat spinal cord-muscle co-culture system and on the voltage-dependent calcium channel (VDCC) current in cerebellar granule cells and Purkinje cells using the whole-cell patch clamp technique. The frequency of spontaneous muscle action potential of the innervated muscle cells was transiently increased by IgM anti-GQ1b mAb and then was blocked completely, which was the same finding as reported previously. Moreover, the cerebellar granule cell VDCC current was decreased by 30.76 ± 7.60% by 5 μg/mL IgM anti-GQ1b mAb, whereas IgM anti-GQ1b mAb did not affect the VDCC current in cerebellar Purkinje cells. In immunocytochemistry, IgM anti-GQ1b mAb stained the whole cell surface of cerebellar granule cells, but not that of Purkinje cells. Therefore, the clinical symptoms of Miller–Fisher syndrome, such as cerebellar-like ataxia, may be explained by the inhibitory effects of anti-GQ1b antibodies on VDCC current in cerebellar granule cells.     

Effects of phospholipids on antiganglioside antibody reactivity in GBS

Serum antibody activities to mixtures of a ganglioside and various phospholipids were compared with those to a ganglioside alone in 30 anti-GM1 IgG-positive GBS patients and 30 anti-GQ1b IgG-positive Miller Fisher syndrome (MFS) patients. Anti-GM1-positive sera had higher antibody reactivities against a mixture of GM1 and several phospholipids including PA, PI and PS, than against GM1 alone. In contrast, in case of anti-GQ1b antibody, no phospholipid provided significant enhancement. Sphingomyelin provided decrease of the activity for both anti-GM1 and anti-GQ1b IgG. The effects of phospholipids must be considered to determine the pathogenetic role of antiganglioside antibodies in GBS and MFS.     

Anti-ganglioside antibody and neuropathy: review of our research

Some patients developed Guillain-Barré syndrome (GBS) after the administration of bovine gangliosides. Patients with GBS subsequent to Campylobacter jejuni enteritis frequently have IgG antibody to GM1 ganglioside. Fisher's syndrome (FS), a variant of GBS, is associated with IgG antibody to GQ1b ganglioside. We showed the existence of molecular mimicry between GM1 and lipopolysaccharide (LPS) of C. jejuni isolated from a GBS patient, and that between GQ1b and C. jejuni LPSs from FS patients. Several lines of evidence suggest a pathogenic role for anti-ganglioside antibodies. Some patients developed sensorimotor polyneuropathy after anti-GD2 antibody administration. Anti-GM1 antibody can block motor nerve conduction. The molecular mimicry between infectious agents and gangliosides may function in the production of anti-ganglioside antibodies and the development of GBS and FS. Anti-GQ1b IgG antibody is detected also in Bickerstaff's brainstem encephalitis and acute ophthalmoparesis, which suggests that these conditions are categorized as autoimmune diseases related to FS. Since a tryptophan-immobilized column effectively adsorb anti-GQ1b IgG antibody, immunoadsorption with the column should be considered as an alternative form of plasmapheresis for the anti-GQ1b IgG antibody syndrome.     

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.     

Neuro-ophthalmology and the anti-GQ1b antibody syndromes

The discovery of the association of the anti-GQ1b IgG antibody with the postinfectious clinical syndromes of ophthalmoplegia, ataxia, and areflexia helped house the phenotypes of the Miller Fisher syndrome (MFS), atypical MFS, Guillain-Barr’e syndrome with ophthalmoplegia, and Bickerstaff’s brainstem encephalitis under one roof. The neuro-ophthalmologic signs classically predominate and may vary from case to case, but they maintain clinically recognizable patterns that assist with the diagnosis. The identification of a common lipopolysaccharide on the plasma membrane in human cranial and peripheral nerves at the GQ1b epitope and on infectious particles of bacteria and viruses (ie, Campylobacter jejuni) demonstrates molecular mimicry. The high frequency of oculomotor dysfunction is partially explained by the tissue ganglioside concentration and distribution and the attraction of antibody-stimulating complement activation. Current experimental treatment targets antibody removal and neutralization and prevents membrane attack complex formation through deactivation of complement. This article aims to bring together the historically disparate opinions on the origins of these syndromes as either a purely peripheral nervous system or central nervous system dysfunction, highlight the clinical neuro-ophthalmologic signs, discuss some of the biology of the anti-GQ1b antibody, and review imaging abnormalities and treatment of this fascinating disorder.     

Anti-GQ1b ganglioside antibody in peripheral nervous system disorders: pathophysiologic role and clinical relevance

The recent literature about autoimmune peripheral neuropathies has been dominated by the discovery of antibodies to a variety of glycosphingolipids. Gangliosides are important carbohydrate determinants for autoimmune activity, and several studies have suggested that serum antibodies against gangliosides are responsible for some forms of acute and chronic neuropathy syndromes. However, this view is disputable, and despite substantial progress in understanding the potential pathogenic effects of antiganglioside antibodies, many central issues remain unresolved across the whole pathogenic process. Miller Fisher syndrome has been classified as a variant of Guillain-Barré syndrome that comprises the clinical triad of ataxia, areflexia, and ophthalmoplegia. It has been considered the archetypal antiganglioside antibody-mediated human neuropathy because anti-GQ1b ganglioside antibody is detected in most patients with Miller Fisher syndrome, decays rapidly with clinical recovery, and is not found in normal and disease control serum samples. The only other case in which this antibody is found is in patients with related conditions, which might share the same pathogenic mechanism, such as Bickerstaff brainstem encephalitis. The strength of this close serologic-clinical association is such that measurement of anti-GQ1b antibody in suspected cases of Miller Fisher syndrome is a useful diagnostic marker for clinicians. This article reviews the occurrence, the pathophysiologic role, and the clinical background of anti-GQ1b ganglioside antibody in Miller Fisher syndrome and related disorders.     

A polyclonal antibody to protein disulfide isomerase induces platelet aggregation and secretion

Monoclonal mouse antiplatelet antibodies against a variety of platelet surface components can activate platelets, causing platelet aggregation and secretion. The mechanism involves binding of the Fab domain to a platelet surface antigen, and the activation occurs through an interaction of the Fc domain with the platelet FcγRII receptor. There is almost no information on FcγRII receptor-dependent activation of platelets by polyclonal rabbit antibodies. We presently report that a polyclonal rabbit antibody to a platelet surface antigen, protein disulfide isomerase, induces platelet aggregation and secretion. These effects are seen with concentrations of the antiprotein disulfide isomerase antibody as low as 25 to 40 μg/mL. Fab and F(ab′)₂ preparations of the rabbit antiprotein disulfide isomerase antibody do not cause aggregation. Fab made from the rabbit antiprotein disulfide isomerase antibody as well as a monoclonal antibody to the FcγRII (IV.3) receptor block the aggregation and secretion responses. Aggregation and secretion are inhibited by an antiglycoprotein IIbIIIa antibody, which blocks fibrinogen binding and wortmannin, an inhibitor of phosphoinositide 3-kinase. Aspirin, prostaglandin E₁, and Ethylenediaminetetraacetic acid (EDTA) also block the platelet responses. These data suggest that activation of platelets by polyclonal antibodies occurs by mechanisms similar to those found with activating monoclonal antibodies.     

A case of Miller Fisher syndrome with pharyngeal palsy as an initial symptom]

We report herein a rare case of Miller Fisher syndrome with pharyngeal palsy as an initial symptom. A 68-year-old man admitted to our hospital with pharyngeal palsy two weeks after a respiratory infection. He subsequently developed ataxic gait, paresthesia in the upper limbs and ophthalmoplegia. Double-filtrated-plasmapheresis had been performed four times and all the symptoms subsided within two months. In the acute phase of the disease, the titers of anti-GQ1b and GT1a antibodies were elevated. The titer of anti-GT1a antibody was higher than that of anti-GQ1b antibody. Recently, the activity of serum anti-GT1a antibody has been supposed to be associated with pharyngeal palsy. In the present case, higher titer of anti-GT1a antibody compared with that of anti-GQ1b antibody could possibly cause pharyngeal palsy as an initial symptom of Miller Fisher syndrome.     

Ataxic Guillain-Barré syndrome associated with anti-GM1b and anti-GalNAc-GD1a antibodies

Abstract. Ataxic Guillain-Barré syndrome (GBS) associated with anti-GQ1b IgG antibody has been reported. We, however, have had a patient with ataxic GBS who had IgG antibodies to the minor gangliosides GM1b and GalNAc-GD1a, and we therefore retrospectively investigated the clinical features of patients who had antibodies to GM1b or GalNAc-GD1a, but not to GQ1b. Information on patients antecedent illnesses, initial symptoms, neurological signs, and CSF findings was reviewed in those with ataxic GBS or Fisher syndrome (FS) with anti-GM1b or anti-GalNAc-GD1a IgG antibodies. We tested whether the anti-GM1b and anti-GalNAc-GD1a antibodies are cross-reactive and constructed three-dimensional structural models of GM1b and GalNAc-GD1a. Ataxic GBS was diagnosed in 1 of 65 patients who had both anti-GM1b and anti-GalNAc-GD1a antibodies and in 3 of 159 patients who had anti-GM1b antibody without anti-GalNAc-GD1a antibody: FS was diagnosed in 1 of the 159 patients and in 1 of 35 who had anti-GalNAc-GD1a antibody without anti-GM1b antibody. All the patients antibodies to GM1b or GalNAc-GD1a were associated with the IgG isotype. The clinical features of patients with ataxic GBS associated with anti-GM1b or anti-GalNAc-GD1a IgG antibodies did not differ from those of patients who had anti-GQ1b IgG antibody. Absorption study findings for serum from the patient who had both anti-GM1b and anti-GalNAc-GD1a IgG antibodies showed significant absorbance of anti-GM1b IgG antibody by GalNAc-GD1a and of anti-GalNAc-GD1a IgG antibody by GM1b, indicating that these antibodies are cross-reactive. This is the first report of ataxic GBS or FS associated with anti-GM1b or anti-GalNAc-GD1a IgG antibodies. These autoantibodies, as well as anti-GQ1b IgG antibody, may function in the development of some patients with ataxic GBS and FS.     

Presynaptic N-methyl-D-aspartate receptor activation inhibits neurotransmitter release through nitric oxide formation in rat hippocampal nerve terminals

In brain synapses, nitric oxide synthase activation is coupled to N-methyl-D-aspartate-mediated calcium entry at postsynaptic densities through regulatory protein complexes, however a presynaptic equivalent to this signaling mechanism has not yet been identified. Novel evidence indicates that N-methyl-D-aspartate glutamate receptors may play a presynaptic role in synaptic plasticity. Thus, we investigated whether ionotropic glutamate receptor activation in isolated nerve terminals regulates neurotransmitter release, through nitric oxide formation. N-Methyl-D-aspartate dose-dependently inhibited the release of glutamate evoked by 4-aminopyridine (IC(50)=155 microM), and this effect was reversed by the N-methyl-D-aspartate receptor antagonist D-(-)-2-amino-5-phosphopentanoic acid and by the nitric oxide synthase inhibitor, L-nitroarginine, in synaptosomes isolated from whole hippocampus, CA3 and CA1 areas, but not from the dentate gyrus. In contrast, the 4-aminopyridine-evoked release of glutamate was reduced by alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid or kainate by a nitric oxide-independent mechanism, since it was not blocked by L-nitroarginine, and N-methyl-D-aspartate, but not alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid or kainate, significantly increased cGMP formation. Presynaptic N-methyl-D-aspartate receptors are probably involved since removing extracellular nitric oxide with the scavenger 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl 3-oxide did not block the depression of glutamate release by N-methyl-D-aspartate. The mechanism underlying this depression involves the inhibition of synaptic vesicle exocytosis since N-methyl-D-aspartate/nitric oxide inhibited the release of [3H]glutamate and [14C]GABA evoked by hypertonic sucrose. The results also suggest that presynaptic N-methyl-D-aspartate receptors may function as auto- and heteroreceptors.     

Acute isolated ophthalmoplegia with anti-GQ1b antibodies

Ophthalmoplegia without ataxia, areflexia or both has been designated as atypical Miller Fisher syndrome (MFS) or acute ophthalmoplegia (AO). This entity, first reported by Chiba et al. is associated with anti-GQ1b IgG antibodies.We report a patient with isolated acute ophthalmoplegia with high titer of anti-GQ1b IgG antibody activity in the acute phase in whom treatment with intravenous immunoglobulin (IVIg) led to the clinical recovery and the decrease in antibody titer.     

Development of testing kits of anti-ganglioside antibody: clinical utility in Guillain-Barré and Fisher syndromes]

We developed testing kits for anti-GM1 and anti-GQ1b IgG antibodies and examined their utilities in supporting the diagnosis of Guillain-Barré syndrome (GBS) and Fisher syndrome (FS). Anti-GM1 antibody was detected in 49% of 95 patients with GBS and in 5% or less of disease and normal controls. Anti-GQ1b antibody was detected in 85% of 55 patients with FS, whereas in none of the controls. Eight GBS patients, in whom anti-GM1 IgG antibody was judged negative using the kit, were found to have other anti-ganglioside IgG antibodies. Four of them showed ophthalmoplegia and had anti-GQ1b IgG antibody. Detection of anti-GM1 IgG antibody in GBS and of anti-GQ1b IgG antibody in FS within one week after the disease onset were significantly more frequent compared to albuminocytologic dissociation in the cerebrospinal fluids (GBS, 58% vs 32%; FS, 89% vs 20%). These findings indicate that our testing kits are useful for supporting the early diagnosis of GBS and FS.