Nobuhiro Yuki

Acute axonal polyneuropathy associated with anti‐GM1 antibodies following Campylobacter enteritis

We report 2 patients with Guillain-Barré syndrome (GBS) following Campylobacter jejuni enteritis. Electrophysiologic studies indicated that the predominant process was axonal degeneration of motor nerves, and clinical recovery was poor. Serum testing by thin-layer chromatography and enzyme-linked immunosorbent assay revealed that the sera from both patients contained high titers of IgG antibody against GM1 ganglioside. These cases may represent a subgroup of GBS as acute axonal polyneuropathy following C jejuni enteritis associated with anti-GM1 antibodies.

Animal model of axonal Guillain‐Barré syndrome induced by sensitization with GM1 ganglioside

Some humans develop the axonal form of Guillain‐Barré syndrome after receiving bovine brain ganglioside. On sensitization with the ganglioside mixture, all of a group of rabbits injected developed high anti‐GM1 IgG antibody titers, flaccid limb weakness of acute onset, and a monophasic illness course. Pathological findings for the peripheral nerves showed predominant Wallerian‐like degeneration, with neither lymphocytic infiltration nor demyelination. IgG was deposited on the axons of the anterior roots, and GM1 was proved to be present on the axons of peripheral nerves. Sensitization with purified GM1 also induced axonal neuropathy, indicating that GM1 was the immunogen in the mixture. A model of human axonal Guillain‐Barré syndrome has been established that uses inoculation with a bovine brain ganglioside mixture or isolated GM1. This model may help to clarify the molecular pathogenesis of the syndrome and to develop new treatments for it.

Axonal Guillain-Barré syndrome: Relation to anti-ganglioside antibodies and Campylobacter jejuni infection in Japan

To clarify the relations of the axonal form of Guillain‐Barré syndrome (GBS) to anti‐ganglioside antibodies and Campylobacter jejuni infection, 86 consecutive Japanese GBS patients were studied. Electrodiagnostic criteria showed acute inflammatory demyelinating polyneuropathy in 36% of the patients and acute motor axonal neuropathy (AMAN) in 38%. Frequent anti‐ganglioside antibodies were of the IgG class and against GM1 (40%), GD1a (30%), GalNAc‐GD1a (17%), and GD1b (21%). Identified infections were C. jejuni (23%), cytomegalovirus (10%), Mycoplasma pneumoniae (6%), and Epstein‐Barr virus (3%). There was a strong association between AMAN and IgG antibodies against GM1, GD1a, GalNAc‐GD1a, or GD1b. Almost all the patients with at least one of these antibodies had the AMAN pattern or rapid resolution of conduction slowing/block possibly because of early‐reversible changes on the axolemma. C. jejuni infection was frequently associated with AMAN or anti‐ganglioside antibodies, but more than half of the patients with AMAN or anti‐ganglioside antibodies were C. jejuni–negative. These findings suggest that the three phenomena “axonal dysfunctions (AMAN or early‐reversible conduction failure),” “IgG antibodies against GM1, GD1a, GalNAc‐GD1a, or GD1b,” and “C. jejuni infection” are closely associated but that microorganisms other than C. jejuni frequently trigger an anti‐ganglioside response and elicit axonal GBS. Ann Neurol 2000;48:624–631

Anti-GM1 Antibodies Cause Complement-Mediated Disruption of Sodium Channel Clusters in Peripheral Motor Nerve Fibers

Voltage-gated Na+ (Nav) channels are highly concentrated at nodes of Ranvier in myelinated axons and facilitate rapid action potential conduction. Autoantibodies to gangliosides such as GM1 have been proposed to disrupt nodal Nav channels and lead to Guillain-Barré syndrome, an autoimmune neuropathy characterized by acute limb weakness. To test this hypothesis, we examined the molecular organization of nodes in a disease model caused by immunization with gangliosides. At the acute phase with progressing limb weakness, Nav channel clusters were disrupted or disappeared at abnormally lengthened nodes concomitant with deposition of IgG and complement products. Paranodal axoglial junctions, the nodal cytoskeleton, and Schwann cell microvilli, all of which stabilize Nav channel clusters, were also disrupted. The nodal molecules disappeared in lesions with complement deposition but no localization of macrophages. During recovery, complement deposition at nodes decreased, and Nav channels redistributed on both sides of affected nodes. These results suggest that Nav channel alterations occur as a consequence of complement-mediated disruption of interactions between axons and Schwann cells. Our findings support the idea that acute motor axonal neuropathy is a disease that specifically disrupts the nodes of Ranvier.

Clinical features and prognosis of Miller Fisher syndrome

Article abstract— The authors reviewed the clinical features and outcome of Miller Fisher syndrome (MFS) for 50 consecutive patients with MFS including 28 patients who received no immunotherapy. Besides the characteristic clinical triad (ophthalmoplegia, ataxia, and areflexia), pupillary abnormalities, blepharoptosis, and facial palsy are frequent in MFS, whereas sensory loss is unusual despite the presence of profound ataxia. Patients with MFS usually had good recovery and no residual deficits.

Infectious origins of, and molecular mimicry in, Guillain-Barré and Fisher syndromes

Guillain-Barré syndrome (GBS), characterised by limb weakness and areflexia, is the prototype of postinfectious autoimmune diseases, and Campylobacter jejuni is the most frequent antecedent pathogen. GBS subsequent to C jejuni enteritis is associated with a severe, pure motor axonal variant and IgG antibodies against GM1, GM1b, GD1a, or GalNAc-GDla, gangliosides expressed in human peripheral nerves. Lipopolysaccharides of C jejuni isolated from GBS patients have ganglioside-like epitopes. Cytomegalovirus is the most common viral antecedent infection. Patients with demyelinating GBS who have had a recent CMV infection have severe sensory deficits and anti-GM2 IgM antibody. CMV-infected fibroblasts express the GM2 epitope. Fisher syndrome (FS), characterised by ophthalmoplegia, ataxia, and areflexia, is a GBS variant associated with anti-GQ1b IgG antibody. GQ1b is enriched in the cranial nerves that innervate the extraocular muscles. Some patients develop FS after C jejuni infection, and the lipopolysaccharide present bears the GQ1b epitope. Molecular mimicry is a possible cause of GBS and FS.

Frequent presence of anti-GQ1b antibody in Fisher's syndrome.

We used the enzyme-linked immunosorbent assay to investigate autoantibodies against the gangliosides GM1, GD1a, GD1b, GT1b, GD2, and GQ1b, in sera from 16 patients with Fishers syndrome. We found high anti-GQlb antibody titers, mainly those of the IgG class, in the sera of 13 of these patients. The titers decreased with the clinical course of the illness. Moreover, anti-GQlb antibody-positive patients had more severe ataxia of cerebellar type than the antibody-negative patients.

Antecedent infections in Fisher syndrome A common pathogenesis of molecular mimicry

Objective: To assess the production mechanism of anti-GQ1b autoantibody in Fisher syndrome (FS). Methods: The authors conducted a prospective case-control serologic study of five antecedent infections (Campylobacter jejuni, cytomegalovirus, Epstein–Barr virus, Mycoplasma pneumoniae, and Haemophilus influenzae) in 73 patients with FS and 73 sex- and age-matched hospital controls (HCs). Serologic evidence in FS patients of C. jejuni (21%) and H. influenzae (8%) infections was present significantly more often than in the HCs. None of the five pathogens examined was found in the 49 (67%) patients with FS. Anti-GQ1b IgG antibody was detected in most FS patients infected with C. jejuni or H. influenzae. Mass spectrometry analysis identified a C. jejuni strain (CF93-6) carrying a GT1a-like lipo-oligosaccharide (LOS) that had been isolated from an FS patient. Immunization of complex ganglioside-lacking knockout mice with the GT1a-like LOS generated IgG class monoclonal antibodies (mAbs) that reacted with GQ1b and GT1a. Thin-layer chromatography with immunostaining showed that anti-GQ1b mAb bound to the C. jejuni LOS (50% of the 20 FS-related strains) more commonly than in the Guillain–Barré syndrome (GBS)–related (7% of 70) or enteritis-related (20% of 65) strains. Anti-GM1 and anti-GD1a mAbs also reacted with the LOS from some FS-related strains (both 20%), but binding frequencies were higher in the GBS-related strains (74 and 57%). The GQ1b epitope was detected in 4 (40%) of the 10 FS-related H. influenzae strains but was absent in strains from patients with GBS (n = 4) and uncomplicated respiratory infections (n = 10). Conclusions: C. jejuni and H. influenzae are related to Fisher syndrome (FS) development, and production of anti-GQ1b autoantibody is mediated by the GQ1b-mimicking lipo-oligosaccharides on those bacteria. The causative agents remain unclear in the majority of patients with FS.

The crucial role of Campylobacter jejuni genes in anti-ganglioside antibody induction in Guillain-Barre syndrome

Molecular mimicry of Campylobacter jejuni lipo-oligosaccharides (LOS) with gangliosides in nervous tissue is considered to induce cross-reactive antibodies that lead to Guillain-Barre syndrome (GBS), an acute polyneuropathy. To determine whether specific bacterial genes are crucial for the biosynthesis of ganglioside-like structures and the induction of anti-ganglioside antibodies, we characterized the C. jejuni LOS biosynthesis gene locus in GBS-associated and control strains. We demonstrated that specific types of the LOS biosynthesis gene locus are associated with GBS and with the expression of ganglioside-mimicking structures. Campylobacter knockout mutants of 2 potential GBS marker genes, both involved in LOS sialylation, expressed truncated LOS structures without sialic acid, showed reduced reactivity with GBS patient serum, and failed to induce an anti-ganglioside antibody response in mice. We demonstrate, for the first time, to our knowledge, that specific bacterial genes are crucial for the induction of anti-ganglioside antibodies.

Bickerstaff's brainstem encephalitis and Fisher syndrome form a continuous spectrum: clinical analysis of 581 cases.

Whether Bickerstaffs brainstem encephalitis (BBE) is a distinct disease or a subtype of Fisher syndrome (FS) is unclear as there have been no clinical studies with sufficiently large numbers of patients with FS or BBE. Our aim was to clarify the nosological relationship. Medical records of patients suffering acute ophthalmoplegia and ataxia within four weeks of onset were reviewed. BBE was the diagnosis for patients with impaired consciousness, FS for those with clear consciousness and areflexia. Clinical features, neuroimages, and laboratory findings were analyzed. Patients were grouped as having BBE (n = 53), FS (n = 466), or as unclassified (n = 62). The BBE and FS groups had similar features; positive serum anti-GQ1b IgG antibody (68 % versus 83 %), antecedent Campylobacter jejuni infection (23 % versus 21 %), CSF albuminocytological dissociation (46 % versus 76 %), brain MRI abnormality (11 % versus 2 %), and abnormal EEG findings (57 % versus 25 %). BBE (n = 4) and FS (n = 28) subgroups underwent detailed electrophysiological testing. Both groups frequently showed absent soleus H-reflexes, but normal sensory nerve conduction (75 % versus 74 %) and a 1-Hz power spectrum peak on postural body sway analysis (67 % versus 72 %). Common autoantibodies, antecedent infections, and MRI and neurophysiological results found in this large study offer conclusive evidence that Bickerstaffs brainstem encephalitis and Fisher syndrome form a continuous spectrum with variable CNS and PNS involvement.