Anti-GQ1b IgG antibody is associated with ataxia as well as ophthalmoplegia

Close association between the increase in anti-GQ1b immunoglobulin G (IgG) antibody and ophthalmoplegia in Miller Fisher syndrome (MFS) and Guillain-Barré syndrome (GBS) has been reported. We investigated whether anti-GQ1b IgG antibody also is associated with ataxia, another of the MFS triad. Of 149 patients who had anti-GQ1b IgG antibody without profound weakness, 144 showed ophthalmoplegia (120 showed both ophthalmoplegia and ataxia; 24, ophthalmoplegia without ataxia). In contrast, five showed ataxia without ophthalmoplegia. Some large neurons of the dorsal root ganglia were immunostained with anti-GQ1b monoclonal antibody. Anti-GQ1b IgG antibody may thus be associated with ataxia as well as ophthalmoplegia. Ataxia may be due to its binding to a subset of primary sensory neurons.

Hbox1 and Hbox7 are involved in pattern formation in sea urchin embryos

In spite of their potential importance in evolution, there is little information about Hox genes in animal groups that are related to ancestors of deuterostome. It has been reported that only two Hox genes (Hbox1 and Hbox7) are expressed significantly in sea urchin embryos. Expression of Hbox1 protein is restricted to the aboral ectoderm, and Hbox7 expression is restricted to oral ectoderm, endoderm and secondary mesenchyme cells in sea urchin embryos after the gastrula stage. With the aim of gaining insight into the role of Hbox1 and Hbox7 in sea urchin development, Hbox1 and Hbox7 overexpression experiments were performed. Overexpression of Hbox1 repressed the development of oral ectoderm, endoderm and mesenchyme cells. On the contrary, overexpression of Hbox7 repressed the development of aboral ectoderm and primary mesenchyme cells. The data suggest that Hbox1 and Hbox7 are expressed in distinct non-overlapping territories, and overexpression of either one inhibits territory-specific gene expression in the domain of the other. It is proposed that an important function of both Hbox1 and Hbox7 genes is to maintain specific territorial gene expression by each one, in its domain of expression, while repressing the expression of the other in this same domain.

[Guillain-Barré syndrome with cerebellar symptoms and elevated serum anti-GD1b IgG antibody]

We reported a 46-year-old woman with Guillain-Barré syndrome (GBS) after suffering from common cold. She also had cerebellar symptoms; ataxic speech, poor finger-nose and heel-knee tests, dysmetria, dysdiadochokinesis, poor one foot standing, positive Mann's test, ataxic gait, and poor tandem gait without Romberg's sign, and sensory disturbance. We ruled out other diseases with cerebellar symptoms; for example, Wernicke encephalopathy, multiple sclerosis, cerebellar vascular disease and encephalitis in the brain stem and cerebellum. Anti-GD1bIgG antibody was elevated in her serum in the acute phase. She was treated with immuno-adsorption therapy (TR-350) in the acute phase. The antibody titer decreased with clinical improvement after immuno-adsorption therapy. The involvement of the anti-GD1bIgG antibody in the pathogenetic mechanism of peripheral neuropathy and cerebellar symptoms was suggested.

[A case of pharyngeal-cervical-brachial variant of Guillain-Barré syndrome with positive anti-galactocerebroside (Gal-C) IgM antibody]

A 49-year-old man presented with hoarseness, dysphagia, muscle atrophy and weakness of deltoid, trapezius, sternocleidomastoid, rhomboid, anterior serratus, infraspinatus and supraspinatus. Anti-Gal-C IgM antibody was positive in the serum. The other antiganglioside antibodies (GM1, GM2, GM3, GD1a, GD1b, GD3, GT1a, GT1b, GQ1b, GA1, GalNAc-GD1a, GM1b) were negative. Patient contracted pneumonia but whether it was due to mycoplasma was not evident. Plasmapheresis improved his clinical state including a decrease of the antibody. This case was diagnosed pharyngeal-cervical-brachial variant of Guillain-Barré syndrome, and anti-Gal-C antibody seemed to be correlated with the pathogenesis of this syndrome. Gal-C is a major glycolipid of myelin and the cell membrane of the myelin-forming cell (oligodendrocytes and Schwann cells) and is free of specific localization and distribution. The mechanism how the anti-Gal-C IgM antibody induced bulbar paralysis and the symptoms localizing neck and upper limbs remains to be known.

Monospecific anti-GD1b IgG is required to induce rabbit ataxic neuropathy

Of 22 rabbits sensitized with GD1b, 12 developed experimental sensory ataxic neuropathy. The affected rabbits had a higher level of serum IgG monospecific to GD1b than the unaffected ones. The GD1b-positive neuronal cytoplasms of rabbit dorsal root ganglia had larger diameters than the negative ones. IgG antibody monospecific to GD1b may preferentially bind to large primary sensory neurons, causing sensory ataxic neuropathy.

Rabbit experimental sensory ataxic neuropathy: anti-GD1b antibody-mediated trkC downregulation of dorsal root ganglia neurons

We previously reported experimental sensory neuropathy in rabbit induced by the immunization of ganglioside GD1b. The major pathological change in diseased rabbits was degeneration of primary sensory neurons with central axons extending to the dorsal column of the spinal cord. The loss of primary sensory neurons that mediate proprioceptive sensation prompted us to investigate the expression of trkC in dorsal root ganglia (DRG) because this type of neuron is thought depend mainly on neurotrophin-3-mediated trkC signaling. Northern blotting analysis revealed markedly reduced expression of trkC in DRG of diseased rabbits in acute phase. This result together with the absence of lymphocytic infiltration in DRG of diseased rabbits at any stage suggests the anti-GD1b antibody-mediated downregulation of trkC expression could be one of the pathogenesis of this experimental sensory ataxic neuropathy.

Dorsal root ganglia neuron-specific promoter activity of the rabbit beta-galactoside alpha1,2-fucosyltransferase gene

The rabbit H-blood type alpha1,2-fucosyltransferase (RFT-I), gene and its biosynthetic products, H antigens (Fucalpha1,2Galbeta), are abundantly expressed in a subset of dorsal root ganglia (DRG) neurons. To investigate the regulatory mechanisms for the RFT-I gene expression, we determined the genomic structure and promoter activity of this gene. PCR amplification of the 5' cDNA end analysis revealed two transcriptional start sites, 498 and 82 nucleotides upstream of the translational initiation codon, the latter site yielding a major 3.1-kb transcript specifically expressed in DRG, as revealed by Northern blotting. Promoter analysis of the 5'-flanking region of the RFT-I gene using a luciferase gene reporter system demonstrated strong promoter activity in PC12 cells, which express the rat H-type alpha1,2-fucosyltransferase gene, and Neuro2a mouse neuroblastoma cells. Deletion analysis revealed the 704-base pair minimal promoter region flanking the translational initiation codon, for which two distinct promoter activities were detected and differentially used in PC12 and Neuro2a cells. The minimal promoter region contained a GC-rich domain (GC content 80%), in which a Sp1 binding sequence and a GSG-like nerve growth factor-responsive element were found, but lacked TATA- and CAAT-boxes. Promoter analysis with a primary culture of DRG neurons demonstrated that the minimal promoter region of the RFT-I gene was sufficient for the expression of a reporter gene in DRG neurons. We conclude that the TATA-less GC-rich minimal promoter region of the RFT-I gene controls DRG small neuron-specific expression of the RFT-I gene.

[Antiganglioside antibodies in the pathogenesis of autoimmune neuropathies]

Antiganglioside antibodies are frequently detected in sera from patients with autoimmune neuropathies, such as Guillain-Barré syndrome, Miller Fisher syndrome, IgM paraproteinemic neuropathy, chronic inflammatory demyelinating polyneuropathy, and multifocal motor neuropathy. In the acute phase sera from GBS patients, antiganglioside antibodies are detected in 60-70%. Ganglioside antigens recognized by serum antibodies are varied from case to case. IgG antibody against GQ1b ganglioside is specifically raised in sera from patients with Miller Fisher syndrome and Guillain-Barré syndrome with ophthalmoplegia. That antibody may bind to the paranodal myelin of oculomotor, trochlear and abducens nerves, where GQ1b ganglioside is specifically localized, to cause ophthalmoplegia. IgM M-protein which recognizes the disialosyl residue of GD1b is specifically associated with sensory ataxic neuropathy. The IgM M-protein may bind to the primary sensory neurons, where GD1b ganglioside is localized, to cause sensory disturbance. After we confirmed the localization of GD1b in the rabbit primary sensory neurons, we sensitized rabbits with GD1b and induced sensory ataxic neuropathy in them. This is the first established animal model of autoimmune neuropathy induced by sensitization with ganglioside. Some antiganglioside antibodies may determine the clinical phenotype of neuropathy by binding specifically to the ganglioside antigens which have unique localization.

The pattern of antiganglioside antibody reactivities producing myelinated nerve conduction block in vitro

We studied the pattern of human antiganglioside antibody reactivities causing an acute conduction block in rat myelinated nerve fibers, using an in vitro preparation of the sciatic-tibial nerve. With the aid of complements, IgM antibodies reacting with the terminal disaccharide of galactose (beta1-3)N-acetylgalactosamine produced the block. These findings may help us to understand the mechanism in which the conduction block occurs in neuropathies associated with antiganglioside antibodies.

[A case of atypical Guillain-Barré syndrome exclusively showing multiple cranial nerve palsy with an elevation of anti-GQ1b and anti-GT1a IgG antibodies]

This is a case report of atypical Guillain-Barré syndrome (GBS). A 42-year-old woman displayed pharyngeal paralysis after a mild upper respiratory infection, subsequently having developed ophthalmoplegia, facial diplegia and accessory nerve palsy within about ten days. She had neither weakness nor abnormal tendon reflexes in the extremities. During the acute phase of the disease we found significant elevation of anti-GQ1b and anti-GT1a IgG antibodies in the serum, and immunoadsorption therapy had a remarkable effect on the symptoms. Although our case was extremely atypical of GBS in terms of exclusively showing multiple cranial nerve palsy and lacking areflexia, the elevation of anti-glycolipid antibodies during the acute phase suggests that this case shares pathogenesis with GBS.

[Bickerstaff's brainstem encephalitis with one-and-a-half syndrome]

We presented a case of Bickerstaff's brainstem encephalitis. A 50-year-old woman developed semicoma, external ophthalmoplegia, hyporeflexia, extensor plantar responses. A high titer of anti-GQ1b IgG antibody was detected in her acute phase serum. Auditory brainstem response suggested the presence of brainstem lesion. Although MRI and CSF showed no abnormality, one-and-a-half syndrome was observed during the clinical course, suggesting involvement of the pontine tegmentum. She received steroid pulse-therapy and symptoms disappeared completely. Our case suggested that anti-GQ1b IgG antibody might relate to the pathogenesis of intramedullary as well as extramedullary lesions.

Anti-GQ1b ganglioside antibody and ophthalmoplegia of undetermined cause

BACKGROUND/AIM

Serum antibody against ganglioside GQ1b is reported to be closely associated with immune mediated ophthalmoplegia in the Fisher and Guillain-Barré syndromes. Its presence against glycolipids, in particular ganglioside GQ1b, was investigated in patients with ophthalmoplegia of unknown origin.

METHODS

16 patients with ophthalmoplegia, the cause of which could not be confirmed from clinical findings or diagnostic testing, were tested. 34 patients who had ophthalmoplegia of definite cause, 16 healthy people, and 23 patients with typical Fisher syndrome served as the controls. The ELISA was used to check for serum antibodies against glycolipids in all study participants.

RESULTS

Two of the 16 patients with ophthalmoplegia of unknown cause had serum IgG antibody against GQ1b but not against other glycolipids, and 22 of the 23 patients with typical Fisher syndrome had this antibody. No anti-GQ1b antibodies were found in the patients with ophthalmoplegia of definite cause or in the normal controls.

CONCLUSION

A common underlying cause appears to bring about the pathogenesis of palsy in Fisher syndrome and in the ophthalmoplegia with positive anti-GQ1b IgG antibody, called atypical Fisher syndrome. This antibody may prove a useful clinical marker for differentiating Fisher syndrome, typical and atypical, in patients with ophthalmoplegia.

Differential expression of sea urchin Otx isoform (hpOtxE and HpOtxL) mRNAs during early development

Two distinct types of orthodenticle-related proteins (early type: HpOtxE, late type: HpOtxL) of the sea urchin, Hemicentrotus pulcherrimus, have been implicated as enhancer element binding factors of the aboral ectoderm-specific arylsulfatase (HpArs) gene. In order to understand the role of these isoforms during sea urchin development, we have isolated and characterized HpOtx gene. Here we describe the spatial expression patterns of HpOtxE and HpOtxL mRNAs and effects of overexpression of these mRNAs on embryogenesis. Whole-mount in situ hybridization using each isoform-specific probe reveals the complex and dynamic change of expression patterns among three germ layers. HpOtxE mRNA is maternally stored and exists apparently in a nonlocalized manner by the blastula stage. After hatching, HpOtxE transcripts are expressed predominantly in presumptive endoderm cells and gradually decrease during gastrulation. Signals for HpOtxL mRNA are intense at the vegetal half after hatching and subsequently, its expression is restricted to the micromere-derived cells. After primary mesenchyme cell (PMC) ingression, HpOtxL transcripts are localized at the vegetal plate and thereafter, concentrated primarily in ectoderm. Eggs injected with HpOtxE or HpOtxL mRNA develop into similar radialized structures without PMC ingression and gut invagination, whose oral-aboral axes are disrupted. Overexpression of HpOtxE induces accumulation of HpOtxL mRNA at the significantly earlier stages, though HpOtxL overexpression inhibits the accumulation of HpOtxE transcripts. Expression patterns of HpOtxE and HpOtxL in all three germ layers and dramatic morphological changes observed in the mRNA-injected embryos suggest that each HpOtx isoform has an important role in sea urchin embryogenesis.

Dorsal root ganglia-specific expression of the beta-galactoside alpha1,2-fucosyltransferase genes in rabbits

The neurons of dorsal root ganglia (DRG) mediate several sensation modalities. The carbohydrate antigens on DRG neurons differ with the sensation modalities that subsets of neurons convey. Despite the important roles of gangliosides and glycoproteins in neuronal differentiation and neuritogenesis of the mammalian nervous system, little is known about the mechanisms underlying the regulation of glycosylation. We previously demonstrated the expression of H-blood type antigens (Fuc alpha1, 2Gal beta) on rabbit DRG neurons of small diameter and dramatic changes in H antigens during the perinatal period. To investigate the possible biological roles and regulatory mechanisms of H antigens, we recently cloned three types of rabbit alpha1,2-fucosyltransferase gene that catalyze the biosynthesis of H antigens. Here, we analyze the expression of these genes, RFT-I, II, and III, in rabbit DRG. The H-type alpha1,2-fucosyltransferase gene, RFT-I, was expressed in DRG in late embryos to adult rabbits, as detected on northern blotting. The other two secretor-type alpha1,2-fucosyltransferase genes, RFT-II and III, were observed to be expressed in late embryonic DRG on RT-PCR analysis but were not detectable on northern blotting. The expression of the H-type alpha1,2-fucosyltransferase gene was analyzed by in situ hybridization and was found to be abundant in small-diameter DRG neurons. These results indicate that the H-type alpha1,2-fucosyltransferase gene plays a major role in the regulation of the H antigen expression in DRG during the perinatal period.

Severe motor-dominant neuropathy with IgM M-protein binding to the NeuAcalpha2-3Galbeta- moiety

We report the occurrence of a relapsing, severe predominantly motor neuropathy in a 75-year-old man with an IGM-K M-protein binding to gangliosides GM2, GM3, GM4, GD1a, GT1b and LM1. Motor nerve conduction velocities were slowed with conduction block. A superficial peroneal nerve biopsy specimen revealed segmental demyelination and remyelination. The patient improved after repeated plasma exchanges, and the antibody titer decreased in association with clinical recovery. This IgM M-protein has a unique, previously unreported binding specificity for terminal NeuAcalpha2-3Galbeta- moiety in common to all gangliosides bound by the antibody except GM2. M-proteins with this affinity may be involved in the pathogenesis of this and other cases of motor-dominant demyelinating neuropathy.

Induction of chronic inflammatory arthropathy and mesenchymal tumors in rats infected with HTLV-I

To compare the pathogenicity of HTLV-I derived from patients with HTLV-I-associated myelopathy (HAM)/tropical spastic paraparesis (TSP) and that from patients with adult T-cell leukemia (ATL), neonatal WKA rats were inoculated with either an HTLV-I-infected T-cell line (Fuk line) newly established from a HAM/TSP patient or MT-2 derived from a patient with ATL. Of 38 rats, 34 developed mesenchymal tumors (89%) only after 14 months of age, irrespective of the cell lines used. The rats inoculated with the Fuk line developed severe arthritis (27%) and anti-type II collagen antibody (64%), and less frequently, paraparesis (7%). Those inoculated with MT-2 developed paraparesis (23%), but not arthritis. Cyclophosphamide (CY) administration to induce immunosuppression in the Fuk line-inoculated rats increased the frequency of paraparesis (70%), but decreased the frequency of tumors (20%). HTLV-I proviral DNA was found in the spinal cord, sciatic nerves, tumors, and joints, whereas pX mRNA was detected in the sciatic nerves and tumors, but not in the spinal cord and joints. As a result, HTLV-I is considered to facilitate development of both chronic inflammatory arthropathy associated with autoimmunity and mesenchymal tumors in rats by experimental infection, and its pathogenicity is likely to be greatly influenced by the host immune state.

Binding of antibodies against GM1 and GD1b in human peripheral nerve

Human dorsal root ganglia (DRG), and ventral and dorsal roots were immunostained with rabbit antibodies recognizing GM1, GD1b, or both. Sera from rabbits immunized with GM1 or GD1b were separated in affinity columns into three fractions: Rab1, Rab2, and Rab3. Rab1 recognized only GM1, and Rab2 only GD1b; whereas Rab3 recognized both GM1 and GD1b, presumably by binding to the terminal galactosyl beta 1-3N-acetylgalactosaminyl residue. Rab2 and Rab3 immunostained most of the nerve cell bodies in the DRG and paranodal myelin of the ventral and dorsal roots, whereas Rab1 produced no significant immunostaining. These results show that GD1b is localized on the DRG neurons and the paranodal myelin of human peripheral nerve. These places may be the binding sites for anti-GD1b antibodies, including those cross-reactive with GM1, in the sera from patients with autoimmune neuropathies. GM1 may be dispersed in human DRG and dorsal and ventral roots.

[A case of axonal form of Guillain-Barré syndrome associated with anti-GM1b IgG antibody following Penner 4 Campylobacter jejuni infection]

A 41-year-old woman was admitted to the hospital because of diarrhea followed by progressive weakness of all extremities and dysphagia. On neurological examination, she showed facial diplegia, bulbar palsy, flaccid quadriplegia, and absence of all deep tendon reflexes in addition to Laségue's sign. The Campylobacter jejuni Penner type 4 was isolated from the culture of stool. The test of anti-GM1b antibody (IgG) was positive in the serum. The protein content was elevated in the cerebrospinal fluid without pleocytosis. The studies of motor nerve conduction velocity showed a pattern of the axonal neuropathy. This is a case of Guillain-Barré syndrome presenting with the axonal neuropathy possibly due to the immune response directed to GM1b which is triggered by the Campylobacter jejuni Penner type 4 infection.