Anti-GQ1b ganglioside antibodies mediate complement-dependent destruction of the motor nerve terminal.
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Miller-Fisher syndrome is an autoimmune neuropathy characterized by ataxia, areflexia and ophthalmoplegia, and in the majority of cases the presence of high titres of anti-GQ1b ganglioside antibodies. In an ex vivo model, human and mouse anti-GQ1b antibodies have been shown previously to induce a complement-dependent alpha-latrotoxin-like effect on the murine motor endplate, i.e. they bring about massive quantal release of acetylcholine and eventually block neuromuscular transmission. Using immunofluorescence microscopy with image analysis, we show here that the late stages of this electrophysiological effect temporally coincide with the loss of heavy neurofilament (200 kDa) and type III beta-tubulin immunostaining and structural breakdown of the nerve terminal, as demonstrated by electron microscopy. Ultrastructurally, axon terminals were disorganized, depleted of vesicles, and subdivided by the infiltrating processes of capping Schwann cells. These findings provide clear pathological evidence to support a role for anti-ganglioside antibodies in mediating nerve terminal injury and further advance the view that this site may be of importance as a target in some human neuropathies. (+info)
Transcranial magnetic stimulation studies in the Miller Fisher syndrome: evidence of corticospinal tract abnormality.
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OBJECTIVES: To evaluate serial central motor conduction time in the Miller Fisher syndrome. METHOD: Three patients with classic Miller Fisher syndrome were evaluated clinically. They had serial central motor conduction times measured with transcranial magnetic stimulation and nerve conduction studies. Motor evoked potentials were recorded from the first dorsal interossei and abductor hallucis muscles. RESULTS: All three patients showed reduction in central motor conduction times in tandem with gradual clinical improvement at each review. CONCLUSIONS: There is electrophysiological evidence of a central reversible corticospinal tract conduction abnormality in the Miller Fisher syndrome. (+info)
Sequence typing confirms that Campylobacter jejuni strains associated with Guillain-Barre and Miller-Fisher syndromes are of diverse genetic lineage, serotype, and flagella type.
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Guillain-Barre syndrome (GBS) and Miller-Fisher syndrome (MFS) are correlated with prior infection by Campylobacter jejuni in up to 40% of cases. Nucleotide sequence-based typing of 25 C. jejuni isolates associated with neuropathy permitted robust comparisons with equivalent data from approximately 800 C. jejuni isolates not associated with neuropathy. A total of 13 genetic lineages and 20 flaA short variable region nucleotide sequences were present among the 25 isolates. A minority of isolates (4 of 25) had the flaA short variable region nucleotide sequences that were previously proposed as a marker for GBS-associated isolates. These 4 isolates probably represented the Penner serotype 19 lineage, which has been proposed to have an association with GBS. (+info)
Miller Fisher syndrome: toward a more comprehensive understanding.
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PURPOSE: To review recent knowledge on the clinical features, pathology and pathophysiology, diagnosis and treatment of Miller Fisher syndrome (MFS). DATA SOURCES: Clinical and laboratory studies on MFS in the past 10 years were included. RESULTS: A viral infection preceded neurological symptoms in 71.8% of MFS patients. Typical MFS consists of the triad of ataxia, areflexia and ophthalmoplegia. Other cranial nerves are also involved, which may overlap with limb weakness in typical Guillain-Barre syndrome (GBS). Lower cranial nerve variants of GBS, atypical MFS and ataxic neuropathies may overlap, and are thought of as variant forms of MFS. Recurrence and CNS involvement is found more frequently in MFS than in GBS. Antibody to GQ1b, a tetrasyaloganglioside (GQ1b antibody) which is found in close relation to ophthalmoplegia in MFS, is also associated with Campylobacter jejuni (C. jejuni) serotype Penner 2. This suggests that C. jejuni may induce MFS via the GQ1b structure. The GQ1b antibody may lead to the failure of acetylcholine release from motor nerve terminals, which has been confirmed by clinical neurophysiological results. CONCLUSIONS: Many studies have shown similarities in the pathogenesis of MFS and GBS. However, there are still some differences between them, especially in the areas of sensory and CNS involvement. The GQ1b antibody is thought of as one of the key factors in the pathogenesis of MFS, especially with ophthalmoplegia, and it may prove a useful clinical marker in the diagnosis of MFS. (+info)
Structure of Campylobacter jejuni lipopolysaccharides determines antiganglioside specificity and clinical features of Guillain-Barre and Miller Fisher patients.
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Ganglioside mimicry in the lipopolysaccharide (LPS) fraction of Campylobacter jejuni isolated from Guillain-Barre syndrome (GBS) and Miller Fisher syndrome (MFS) patients was compared with isolates from patients with an uncomplicated enteritis. The antibody response to C. jejuni LPS and gangliosides in neuropathy patients and controls was compared as well. LPS from GBS and MFS-associated isolates more frequently contained ganglioside-like epitopes compared to control isolates. Almost all neuropathy patients showed a strong antibody response against LPS and multiple gangliosides in contrast to enteritis patients. Isolates from GBS patients more frequently had a GM1-like epitope than isolates from MFS patients. GQ1b-like epitopes were present in all MFS-associated isolates and was associated with anti-GQ1b antibody reactivity and the presence of oculomotor symptoms. These results demonstrate that the expression of ganglioside mimics is a risk factor for the development of post-Campylobacter neuropathy. This study provides additional evidence for the hypothesis that the LPS fraction determines the antiganglioside specificity and clinical features in post-Campylobacter neuropathy patients. (+info)
Miller Fisher syndrome in adult onset Still's disease: case report and review of the literature of other neurological manifestations.
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Adult-onset Still's disease (AOSD) is a multi-system inflammatory disorder characterized by high spiking fevers, evanescent salmon-coloured rash, arthralgias or arthritis, hepatosplenomegaly, lymphadenopathy and sore throat. There is no specific test or combination of tests that can establish the diagnosis of AOSD and patients may present with other systemic involvement including neurological manifestations in 7-12% of cases. We present a complex case of a patient with AOSD who developed the Miller-Fisher variant of Guillain-Barre syndrome. This immunological disorder of the nervous system has not been described in association with AOSD before. We also review the literature on other neurological manifestations in AOSD. AOSD mimics different disease processes and its multi-system manifestations may complicate the picture further. (+info)
Complex gangliosides at the neuromuscular junction are membrane receptors for autoantibodies and botulinum neurotoxin but redundant for normal synaptic function.
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One specialization of vertebrate presynaptic neuronal membranes is their multifold enrichment in complex gangliosides, suggesting that these sialoglycolipids may play a major functional role in synaptic transmission. We tested this hypothesis directly by studying neuromuscular synapses of mice lacking complex gangliosides attributable to deletion of the gene coding for beta1,4 GalNAc-transferase (GM2/GD2 synthase), which catalyzes an early step in ganglioside synthesis. Our studies show that complex gangliosides are surprisingly redundant for regulated neurotransmitter release under normal physiological conditions. In contrast, we show that they are membrane receptors for both the paralytic botulinum neurotoxin type-A and human neuropathy-associated anti-ganglioside autoantibodies that arise through molecular mimicry with microbial structures. These data prove the critical importance of complex gangliosides in mediating pathophysiological events at the neuromuscular synapse. (+info)
Ganglioside mimicry of Campylobacter jejuni lipopolysaccharides determines antiganglioside specificity in rabbits.
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The core oligosaccharides of Campylobacter jejuni lipopolysaccharides (LPS) display molecular mimicry with gangliosides. Cross-reactive anti-LPS-antiganglioside antibodies have been implicated to show a crucial role in the pathogenesis of the Guillain-Barre and Miller Fisher syndrome. The specificity of the antiganglioside response is thought to depend on the oligosaccharide structure of the ganglioside mimic. To test this hypothesis and to investigate the potential of LPS from Campylobacter strains from enteritis patients to induce an antiganglioside response, we immunized rabbits with purified LPS from eight Campylobacter jejuni reference strains with biochemically well-defined distinct ganglioside mimics and determined the presence of antiganglioside antibodies. All rabbits produced immunoglobulin G (IgM) and IgG anti-LPS antibodies, and the specificity of the cross-reactive antiganglioside response indeed corresponded with the biochemically defined mimic. Most rabbits also had antibody reactivity against additional gangliosides, and there were slight differences in the fine specificity of the antibody response between rabbits that had been immunized with LPS from the same Campylobacter strain. High anti-LPS and antiganglioside titers persisted over a 10-month period. In conclusion, the structure of the LPS only partly determines the antiganglioside specificity. Other strain-specific as well as host-related factors influence the induction and fine-specificity of the cross-reactive anti-LPS-antiganglioside response. (+info)