[Dengue fever with neurologic expression. Three cases in adults]

Dengue fever, unlike most other arboviral diseases, does not usually cause encephalitis. However, neurologic symptoms with poor prognosis have been regularly reported, mostly in Asian children affected by the severe dengue hemorrhagic fever/dengue shock syndrome, and attributed to a non specific, anoxic or metabolic encephalopathy. Recently, first isolations of dengue viruses from CSF or brain tissue, have renewed this concept. We report 3 dengue fever cases with neurologic manifestations and favorable outcome. Occurrence in adult age, during classic (benign) dengue fever (2 cases), and neurologic sequellae (1 case) were the three outstanding features. We point out the proteiform expression of these neurologic changes and their low incidence rate (< 3% in our series of adult dengue fever). Although their pathogenesis is poorly understood, different mechanisms are suggested: encephalopathy (case n. 1), acute specific encephalitis (questionable in case n(o) 2), or post-infective encephalitis (case n(o) 3).

Epilepsia partialis continua: a new manifestation of anti-Hu-associated paraneoplastic encephalomyelitis

We report on 3 anti-Hu-positive patients who presented with clinical and electroencephalographic (EEG) features of epilepsia partialis continua (EPC). Two of the patients had an associated small cell carcinoma. Magnetic resonance imaging (MRI) disclosed a hyperintense nonenhancing focal lesion in T2-weighted images in the sensorimotor area in 2 patients. Histopathological analysis of the lesion revealed inflammatory infiltrates and neuronal cell loss. In the patient who had a postmortem study, these neuropathological changes were not observed in other areas of the nervous system. This study emphasizes that the possibility of an anti-Hu-associated paraneoplastic disorder must be considered in patients with cortical encephalitis presenting with EPC when a brain tumor can be excluded.

Neurological manifestations of malignant and non-malignant dysglobulinaemias

The main neurological manifestations associated with malignant and non-malignant dysglobulinaemias are reviewed. These disorders are classified according to topographic features, pathological changes or association with specific plasma cell disorders. The main clinical, laboratory, immunological and pathological features are summarized. Knowledge of the pathogenesis in this group of disorders has clearly increased in recent years, allowing better diagnosis and treatment.

Demyelinating inflammatory neuropathies, including Guillain-Barré syndrome

The highly complex and multiple mechanisms responsible for the development of demyelinating neuropathies are reviewed, in particular Guillain-Barré syndrome and its variant Miller Fisher syndrome, chronic inflammatory demyelinating neuropathy, multifocal motor neuropathy, anti-myelin-associated glycoprotein neuropathy, as well as experimental models. Recent investigations into the role of auto antibodies against myelin proteins, or glycolipids have given insights into the pathogenesis of demyelinating inflammatory neuropathies.

Prostate-specific antigen in the cerebrospinal fluid leads to diagnosis of solitary cauda equina metastasis: a unique case report and review of the literature

A 79-year-old male patient presented with a subacute cauda syndrome caused by an intradural metastasis of the lumbosacral caudate fibres from an adenocarcinoma of the prostate, which had been treated 5 years earlier with external beam radiation therapy. Diagnosis could not be established by repeated magnetic resonance images (MRIs) during a 2-year period of increasingly severe radicular pain. Eventually, a small tumour mass could be visualized on the fourth MRI. Repeated normal serum prostate-specific antigen (PSA) did not hint at a prostate cancer metastasis (range 2.4-5.1 ng ml(-1)); however, PSA in the cerebrospinal fluid was found to be elevated (29.1 ng ml(-1)). Empirical radiation therapy of the caudate region did not improve radicular pain. Therefore, an exploratory surgical procedure was conducted, which confirmed the suspicion of an intradural prostate cancer metastasis. In conclusion, PSA in the cerebrospinal fluid provides a useful diagnostic tool for detecting intradural prostate cancer metastasis.

Confocal microscopic localization of anti-myelin-associated glycoprotein autoantibodies in a patient with peripheral neuropathy initially lacking a detectable IgM gammopathy

We report here on a patient with anti-myelin-associated glycoprotein (MAG) neuropathy in whom examination of a sural nerve biopsy by multichannel confocal microscopy showed a partly overlapping distribution of MAG and IgM deposits in myelinated fibers. Our data demonstrate that MAG in Schmidt-Lanterman incisures and paranodal loops, as well as some additional HNK-1-positive components of the basal lamina, are the major targets of the anti-MAG monoclonal IgM autoantibodies in this neuropathy in vivo. Perforation of the basal lamina can allow the penetration and binding of anti-MAG IgM inside myelinated fibers. Our results support and extend the notion that the production of monoclonal anti-MAG IgM may be antigenically driven by MAG molecules and that this process may occur in the immunologically privileged environment of the nerve prior to the appearance of a genuine gammopathy in serum.

Reciprocal expression of myelin-associated glycoprotein splice variants in the adult human peripheral and central nervous systems

The L- and S-MAG isoforms differ only at their C-terminus and are believed to be functionally distinct. To obtain information on the relative expression of these alternatively spliced isoforms in humans, we cloned an S-MAG cDNA fragment. The deduced amino-acid sequence of the human S-MAG C-terminus shows fairly conservative substitutions of 4 out of the 10 residues compared to the rodent peptide. Using reverse transcription and a competitive polymerase chain reaction, we show that, in contrast to rodents, the L-MAG splice variant predominates in adult human brain while, like in rodents, S-MAG transcripts are most abundant in peripheral nerve. The results obtained by Western blot analysis and immunohistochemistry are in good agreement with the findings at the mRNA level. Animal experiments may thus be more representative for the role of MAG in human nerve than in brain.

Gene dosage effects in hereditary peripheral neuropathy. Expression of peripheral myelin protein 22 in Charcot-Marie-Tooth disease type 1A and hereditary neuropathy with liability to pressure palsies nerve biopsies

A duplication of a 1.5-Megabase genomic region encompassing the gene for the peripheral myelin protein 22 (PMP22) is found on chromosome 17p11.2-12 in Charcot-Marie-Tooth disease type 1A (CMT1A), whereas the reciprocal deletion is associated with hereditary neuropathy with liability to pressure palsies (HNPP). Since most CMT1A patients harbor three copies of the PMP22 gene, and most HNPP patients carry only a single copy, a gene dosage effect has been proposed as a mechanism for both diseases. We have analyzed the steady-state expression of PMP22 protein in sural nerve biopsies from three CMT1A and four HNPP patients. Quantitative immunohistochemical determination showed that PMP22 protein expression relative to that of myelin protein zero and myelin basic protein was increased in all CMT1A patients and reduced in all HNPP patients, as compared with biopsy samples of patients with normal PMP22 gene expression. These data demonstrate that both neuropathies result from an imbalance of PMP22 protein expression.

Myelin modifications in 8 cases of peripheral neuropathy with Waldenström's macroglobulinemia and anti-MAG activity

Characteristic myelin modifications in patients with IgM monoclonal gammopathy and anti-MAG activity have mainly been studied in cases of undetermined significance, but also exist in cases with indolent Waldenström's macroglobulinemia, i.e., when lymphoplasmocytic infiltration in bone marrow is 15% or more, without any visceral involvement. Since 1983, the authors have examined nerve biopsies from 8 cases with Waldenström's macroglobulinelia by direct immunofluorescence examination on frozen sections and ultrastructural examination. At direct immunofluorescence, fixation of anti-IgM serum on myelinated fibers was present in 7 cases. At ultrastructural examination, a widening of some myelin lamellae at the periphery of a few fibers was visible in 8 cases. A few fibers with hypermyelination were present in 5 cases. In 2 of these 5 cases widening of some myelin lamellae was present in numerous fibers, 88% in one of them. Frequently, there was a major widening of some myelin lamellae with dilated lamellae present in the inner part of the myelin sheath. Certain lamellae were more dilated, up to 50 nm. Occasionally, enlarged lamellae were not compacted with each other. The authors also examined nerve biopsies from 36 patients with IgM monoclonal gammopathy of undetermined significance and anti-MAG activity, but found only one case with major widening of some myelin lamellae. Five other cases with major widening of some myelin lamellae, 4 Waldenström's macroglobulinemia and 1 IgM monoclonal gammopathy of undetermined significance, have been reported. Given that demyelinating neuropathies are far more numerous in cases with IgM monoclonal gammopathy of undetermined significance, it is likely that cases of indolent Waldenström's macroglobulinemia are prone to develop major myelin modifications, possibly due to another mechanism, added to the classic anti-MAG activity.

[Genetic studies in neurology]

The use of either direct or indirect genetic analyses in neurology is becoming ever greater as more genes are identified thanks to the human genome project. Often the methodologies are complex and difficult to understand. The aim of this review is to present various approaches to molecular diagnosis using several different inherited neurological diseases as examples. These include inherited mitochondriopathies, monogenetic disorders like trinucleotid repeat instability syndromes, duplication anomalies and specific point mutations as well as heterogenetic diseases such as limb girdle dystrophy and familial amyotrophic lateral sclerosis. Possible pathogenetic implications can now be proposed as the basis of new therapeutic modalities.

Extensive splice variation and localization of the EHK-1 receptor tyrosine kinase in adult human brain and glial tumors

EHK-1 is a neuronal ELK-related receptor tyrosine kinase which interacts with multiple, membrane-anchored ligands. Recent experiments have suggested a role for some of these ligands in the formation of neuronal pathways. Here, we report the isolation of human EHK-1 cDNAs and the localization of the human EHK-1 gene to chromosome 4q12. Six EHK-1 mRNA splice variants encoding cell-surface receptors with catalytic domains were identified in adult human brain where a 120-kDa EHK-1 protein predominates. Immunohistochemistry for EHK-1 reveals a dendritic staining pattern in cortical neurons and cerebellar Purkinje cells and a marked accumulation of EHK-1 in the somas of pyramidal neurons within the cortex and hippocampus. Interestingly, we have identified lineage aberrant expression of EHK-1 in a number of human gliomas. In addition to functions during development, EHK-1 may be involved in the maintenance of the adult nervous system and contribute to glioma development.

Cerebral infarcts related to isolated middle cerebral artery stenosis

BACKGROUND AND PURPOSE

The clinical presentation of middle cerebral artery (MCA) stenosis, a rarely diagnosed condition, is not well known. The aim of this study was to analyze the stroke patterns of patients with isolated MCA stenosis.

METHODS

Twenty-two patients with cerebral infarcts due to isolated MCA stenosis were analyzed with respect to their clinical syndrome, and cerebral lesions were assessed by neuroimaging. MCA stenosis was diagnosed by transcranial Doppler sonography (TCD) in 16, by TCD and digital subtraction angiography (DSA) in 4, and by DSA alone in 2 patients.

RESULTS

Ten patients (45.5%) had lacunar syndromes, suggesting small-vessel disease, and 12 patients (55.5%) showed signs and symptoms of cortical dysfunction. Cerebral CT or MRI showed no lesion in 2 patients, small deep infarcts in 10, large striatocapsular infarcts in 2, combined piomedullary and striatocapsular infarcts in 4, piomedullary branch infarcts in 3, and MCA trunk infarct in 1.

CONCLUSIONS

The results suggest an association between MCA stenosis and (1) lacunar infarcts and (2) the occurrence of piomedullary MCA branch infarcts alone or in combination with subcortical infarcts. The clinical syndromes and the radiological findings correspond in most cases.

[Bilateral glomus tumors with a blood pressure regulation disorder due to baroreceptor dysfunction]

HISTORY AND CLINICAL FINDINGS

A 73-year-old woman was admitted because of vertigo of recent onset with a tendency to fall down and progressive hearing impairment with tinnitus over the last 2 years. Neurological examination also revealed right recurrent nerve paresis, facial hemispasm and lingual atrophy, pointing to a lesion involving cranial nerves VII, VIII, IX, X and XII. She was found to have spontaneous nystagmus to the left, due to peripheral vestibular function deficit, without otoscopic abnormalities. She was in atrial fibrillation with a blood pressure of 140/80 mm Hg. The suspected cause was a hormonally active glomus jugulare tumour with intermittent hypertension and involvement of several cranial nerves.

INVESTIGATIONS

Repeatedly measured plasma and urinary catecholamine concentration was normal. Neuroradiology showed a contrast-rich lesion close to the jugular vein and the hypoglossal nerve, as well as a tumour in the left retromandibular fossa with displacement of the left internal carotid artery. The suspected cause of these findings was a neurologically asymptomatic left carotid body tumour with multiple cranial nerve deficits (VII, VIII, IX and XII) due to their compression at the base of the skull. No abnormal catecholamine activity could be demonstrated.

TREATMENT AND COURSE

After complete excision of the right carotid body there were no further hypertensive crises. Later on the left carotid body tumour was embolised because it had continued to grow.

CONCLUSION

The repeated hypertensive crises were probably caused by absent blood pressure regulation, the result of destruction of the afferent fibres. This destruction was due to compression of the hypoglossal nerve by the right jugular glomus, at the same time as the contralateral carotid body had been destroyed by tumour.

[Multiple sclerosis: therapy with recombinant beta-1b interferon: initial results with 30 multiple sclerosis patients in northwest Switzerland]

Recombinant interferon beta-1b has been registered with the Swiss health authorities since August 1995. Due to a special arrangement with health insurances it has been possible to prescribe this medication since spring 1995. We report on our experience with the first 30 consecutively treated multiple sclerosis patients. Indication, adverse event profile and clinical response to treatment are described. The most common side effects were local injection site reactions (63%), influenza-like symptoms (50%) and fatigue (33%). As compared to the prestudy period we observed a 49% reduction in the exacerbation rate. Compliance was excellent, possibly due to strict selection and extensive information about possible effects and side effects.

Selective loss of myelin-associated glycoprotein from myelin correlates with anti-MAG antibody titre in demyelinating paraproteinaemic polyneuropathy

The IgM monoclonal autoantibodies of patients with demyelinating paraproteinaemic polyneuropathy recognize a carbohydrate structure present on both myelin-associated glycoprotein (MAG) and protein zero (P0). These autoantibodies are sufficient to cause the disease but the mechanism of demyelination remains unclear. We have analysed nerve biopsies from eight patients with polyneuropathy and anti-MAG antibodies by quantitative immunohistochemistry and find a concordant pattern of reduced expression of myelin markers with the loss of myelinated fibres. We report here novel features of this disease, in particular a selective lack of detectable MAG in a large proportion of myelinated-fibres containing P0, myelin basic protein (MBP) and periaxin. There is also an inverse correlation of the distribution of MAG in peripheral nerve myelin with the serum anti-MAG antibody titres but no correlation of these titres with the loss of myelinated fibres. Double immunofluorescence staining of paraproteinaemic polyneuropathy (PPN) nerves shows anti-MAG IgM deposited on the periphery of myelinated fibres associated with or lacking MAG staining. These data suggest that the binding of anti-MAG antibodies to MAG and/or other myelin component(s) results in MAG downregulation and may have an essential role in the molecular mechanisms leading to demyelination and partial regeneration in this disease.

[Anti-glycoconjugate antibodies and dysglobulinemic or dysimmune peripheral neuropathies]

Different anti-glycoconjugate auto-antibodies are described to be associated with peripheral neuropathies; the anti-MAG monoclonal IgM activity is determined by ELISA or immunoblotting essays, anti-glycolipid activity by ELISA or chromatography and monoclonal gammopathies by commercially available kits. These investigations are limited by possible cross-reactions due to the common glycosilate epitope. The peripheral neuropathies with anti-glycoconjugate auto-antibodies are different: Guillain-Barré syndrome and its variants (anti-GM1, GQ1b, LM1, GD1, GD1a gangliosides or sulfatides), motor neuropathy (anti-GM1 ganglioside), sensory neuropathies (anti-GD3, GD1b, GD1a, GQ1b gangliosides or sulfatides), and chronic myelinic neuropathy with IgM gammopathy (anti-MAG). We review the major clinical and electrophysiological features and discuss the underlying pathophysiological mechanisms.

Paraproteinaemic neuropathies

Paraproteinaemia and neuropathy are each relatively frequent and may be associated by chance. However, a number of significant relationships have to be ruled out in the differential diagnosis. Malignant gammopathy should be excluded: multiple myeloma can lead to compression of the spinal cord or cauda equina; primary amyloidosis is occasionally involved; the rare but intriguing POEMS syndrome, consisting of polyneuropathy, organomegaly, endocrinopathy, M-protein and skin changes, usually accompanies osteosclerotic myeloma. It can be associated with angio-follicular lymph node hyperplasia and needs to be recognized because radioablative therapy is curative. The 'benign' monoclonal gammopathies of undetermined significance, known as MGUS, are much more frequent. There is an IgM MGUS group with predominantly distal sensorimotor demyelinating polyneuropathy and another rather heterogeneous group with IgG or IgA MGUS and a tendency to a favourable response to plasmapheresis. The role of the monoclonal IgG and IgA antibodies is unclear. This chapter has focused on the pathogenetic mechanisms of neuropathies associated with IgM MGUS. In the majority of cases, monoclonal autoantibodies specific for particular carbohydrate epitopes bind to myelin and are now recognized as the primary cause of the disease manifestations, including widening of the myelin lamellae. While the autoantibodies have been shown to bind complement, the presence of inhibitors is invoked to explain the absence of acute inflammatory changes. The epitopes recognized with the highest affinity by the auto-antibodies are present on the myelin-associated glycoprotein (MAG) and could interfere with cell adhesion and cellular signally processes. In addition, binding to antigenically similar glycoproteins, such as PO, PMP-22 and some acidic glycolipids, may be a contributory factor. It is generally accepted that the anti-MAG autoantibodies are inducing a progressive demyelinating polyneuropathy by modifying axon-Schwann cell interactions.

Acute infectious disorders of the spinal cord and its roots with gadolinium-DTPA enhancement in magnetic resonance imaging

We studied three patients with myelomeningoradiculitis caused by Borrelia burgdorferi, herpes zoster virus or cytomegalovirus infection. All patients underwent MRI of the spinal cord with gadolinium-DTPA and showed enhancing lesions of the spinal cord or nerve roots that correlated with clinical signs. Gadolinium-DTPA enhancement may visualize lesions that suggest an inflammation associated with blood-brain-barrier alteration and indicate the diagnosis before serological results are available.

[Acute hepatic porphyria and its neurological syndrome]

Certain of the hepatic porphyrias are classified as belonging to the acute hepatic prophyrias, namely acute intermittent porphyria (AIP), variegate porphyria (VP), hereditary coproporphyria (HCP) and ALA-dehydrase deficiency. The common feature of all acute hepatic porphyrias is the sudden onset of neurological symptoms. The whole syndrome consists of acute abdominal pain crises with autonomic dysfunction, global or focal central nervous system involvement and a predominantly motor polyneuropathy. Mono- or oligosymptomatic manifestations of acute porphyrias occur and are probably underestimated. The laboratory diagnosis of porphyria depends on the measurement of porphyrin precursors in urine, whereas the measurement of porphyrins in urine and feces is essential for evaluation of the porphyria type. Enzyme measurements are used to identify asymptomatic family members whose quantitative excretions of porphyrins are normal. At present the pathogenesis of neurological manifestations of acute porphyrias remains an unsettled question. The major hypotheses are discussed in this paper. The most important precipitating factor in acute hepatic porphyrias is drug ingestion. As many new drugs have not been in use for sufficiently long periods to assess their porphyrogenic activity, it is safer to avoid drugs in patients with porphyria. The most effective treatment of porphyria attacks is the administration of heme. Among the porphyria patients with epileptic seizures requiring antiepileptic medication, treatment with bromides should be taken into consideration.

Recognition of human recombinant myelin associated glycoprotein by anti-carbohydrate antibodies of the L2/HNK-1 family

The L2 and HNK-1 monoclonal antibodies recognize carbohydrate determinants containing sulfate-3-glucuronate that are prominent on cells of neural crest lineages. In humans these epitopes are most abundant on the Myelin Associated Glycoprotein and it was assumed that they co-localize on the same molecules. Recently, in vitro synthesized carbohydrates have provided a basis for the different recognition requirements of these two antibodies. We now provide in vivo evidence that a human melanoma cell line can produce glycoproteins such as fibronectin, which is recognized by both the L2 and HNK-1 antibodies, and simultaneously a transfected Myelin Associated Glycoprotein carrying only L2-type carbohydrates. Conceivably, the differential expression of L2- and HNK-1 type glycans could have a role in development.

[Treatable immune-mediated neuropathies]

We discuss current approaches in the treatment of immune mediated neuropathies and review recent progress in management. Intensive evaluation has led to improved diagnosis of the cause of neuropathies. Because immunosuppressive drugs are potentially hazardous, strict guidelines for their clinical use, including clinical immunological, neurophysiological and histological investigations, should be followed.

[Paraneoplastic subacute sensory Denny-Brown neuronopathy or anti-Hu syndrome: a classical paraneoplastic syndrome]

Paraneoplastic syndromes, or the remote non metastatic effects of cancer, are wellknown entities that may affect any organ or tissue in the body, including the central nervous system. Some have been shown to be associated with autoantibodies against the nervous system. One typical example ist the subacute sensory neuronopathy of Denny-Brown, classically associated with small cell lung cancer. These patients present with the subacute onset of a sensory neuronopathy which may appear as much as one year before the primary tumour is detected. An antibody called anti-Hu has been found in the serum in these patients, which recognizes a neuronal protein called Hu (M.W. 30 to 40 kD). This antibody can currently be detected by a combination of immunological methods such as Western blot analysis or immunohistochemistry.

High-grade B-cell cerebral lymphoma in a patient with anti-myelin-associated glycoprotein IgM paraproteinemic neuropathy

A 74-year-old woman with a sensory neuropathy and IgM M-protein monoclonal gammopathy of undetermined significance developed a fatal B-cell cerebral lymphoma. CSF protein immunofixation revealed intrathecal secretion of a paraprotein of the same heavy- and light-chain isotypes as the serum monoclonal component (IgM-lambda). Reactivation of Epstein-Barr virus was present in the lymphoma cells. Different factors may be involved in the preferential malignant development of the monoclonal B-cell clone within the CNS.

Chronic relapsing neuropathy associated with Castleman's disease (angiofollicular lymph node hyperplasia)

We report a 17-year-old patient who presented a chronic relapsing sensorimotor demyelinating neuropathy with 6 relapses over a 7-year period, preceding by 4 years the diagnosis of a multicentric angiofollicular lymph node hyperplasia. A role for Epstein-Barr virus (EBV) as a trigger of the neuropathy may be suggested by the presence of EBV DNA in the biopsied abdominal abdominal adenopathies. This unusual reported association seems to have a better prognosis than the known chronic progressive form of neuropathy associated with Castleman's disease and the Crow-Fukase syndrome.

Expression and developmental regulation of Ehk-1, a neuronal Elk-like receptor tyrosine kinase in brain

Protein tyrosine kinases are pivotal in central nervous tissue development and maintenance. Here we focus on the expression of Ehk-1, a novel Elk-related receptor tyrosine kinase. Ehk-1 gene expression is observed in the developing and adult central nervous system and is highly regulated throughout development at both the messenger RNA and protein levels. Three messenger RNA transcripts of 8.5, 5.9 and 5.1 kb are detectable in the rat brain and a variety of splice possibilities have been identified. However, a major protein species of around M(r) 120,000 predominates throughout development. Ehk-1 messenger RNA and protein levels are highest in the first postnatal week. By in situ messenger RNA hybridization the gene is expressed by all neurons of the adult brain, but mostly in the hippocampus, cerebral cortex and large neurons of the deep cerebellar nuclei, as well as the Purkinje and granular cells of the cerebellum. At earlier stages of development, transcripts are most prominent in the periventricular germinal layers of the brain. Immunohistochemistry reveals a pronounced membrane associated protein expression in immature neurons. In the adult animal, peak reactivity was found in the neuropil with sparing of most perikarya. The spatial and temporal pattern of ehk-1 gene expression suggests a role in both the development and maintenance of differentiated neurons of the central nervous system.

Pattern of nervous tissue immunostaining by human anti-glycolipid antibodies

Immunostaining of human, bovine and rodent unfixed nervous tissue sections was performed in order to characterize the structures recognized by anti-glycolipid antibodies. Four human sera from patients, two with M-IgM and motor neuron syndrome or motor neuropathy and two with motor neuropathy and polyclonal IgG antibody activity against gangliosides (GL; i.e. GM1, GD1b, GD1a), were utilized. Serum from a patient with sensory neuropathy and M-IgM immunoglobulins with antibody activity against sulfatide (SUL) was included in this series. This study shows that polyclonal and monoclonal anti-glycolipid antibodies give three different patterns of staining. The first is cholera toxin-like showing a more restricted neuronal pattern of staining. The second is peanut agglutinin-like, which includes the carbohydrate epitope shared by a group of glycoproteins in the gray and white matter. The third (anti-SUL) gives a preferential myelin staining. However, sera with anti-GM1 and anti-SUL antibodies recognize a number of closely situated determinants in the gray matter of the spinal cord and in the granule cells, while in peripheral nerves or in neuronal cells in culture their binding produces a different pattern (nodes of Ranvier for anti-GL; myelin for anti-SUL). These findings indicate that immunohistochemistry with anti-GL and anti-SUL antibodies may provide information regarding the glycolipid-bearing anatomical structures as target antigens and further substantiate the role of these molecules in the pathogenesis of autoimmune neurological disorders.

Identification of the glycosylated sequons of human myelin-associated glycoprotein

Myelin-associated glycoprotein (MAG) is a neural cell adhesion molecule expressing the L2/HNK-1 carbohydrate epitope. MAG is heavily glycosylated containing 30% carbohydrate by weight. In this study, human MAG glycopeptides were isolated and sequenced. Of the 9 MAG sequons 7 were glycosylated and 1 was partially glycosylated at Asn106. Asn332 which was not recovered in the glycopeptide fractions was probably not glycosylated. Furthermore, preliminary data indicate that all MAG glycosylated sequons might bear the L2/HNK-1 epitope.

Human myelin/oligodendrocyte glycoprotein: a new member of the L2/HNK-1 family

Myelin/oligodendrocyte glycoprotein (MOG) is a quantitatively minor component of CNS myelin. In this study, human MOG was found to express the L2/HNK-1 epitope on N-linked oligosaccharide structures. This carbohydrate epitope has been found previously in three other characterized human myelin glycoproteins: the myelin-associated glycoprotein, P0, and the oligodendrocyte-myelin glycoprotein. It seems, therefore, that the L2/HNK-1 epitope is expressed frequently in human myelin glycoproteins. Serial lectin affinity chromatography of 14C-glycopeptides indicated that MOG N-oligosaccharide structures are mainly of the complex type, accounting for 77.8% of total radioactivity. In contrast with myelin-associated glycoprotein and P0, which express the L2/HNK-1 epitope on fucosylated structures, in MOG the epitope was detected on all glycopeptide fractions obtained by serial lectin affinity chromatography, although a preferential expression of the L2/HNK-1 epitope was observed on fucosylated structures. Finally, the data indicated that, as for other human myelin glycoproteins, only a subpopulation of MOG molecules expresses the L2/HNK-1 epitope.

Motor conduction block and high titres of anti-GM1 ganglioside antibodies: pathological evidence of a motor neuropathy in a patient with lower motor neuron syndrome

A patient with a progressive lower motor neuron syndrome and neurophysiological evidence of motor axon loss, multifocal proximal motor nerve conduction block, and high titres of anti-ganglioside GM1 antibodies. Neuropathological findings included a predominantly proximal motor radiculoneuropathy with multifocal IgG and IgM deposits on nerve fibres associated with a loss of spinal motor neurons. These findings support an autoimmune origin of this lower motor neuron syndrome with retrograde degeneration of spinal motor neurons and severe neurogenic muscular atrophy.

Delayed appearance of anti-myelin-associated glycoprotein antibodies in a patient with chronic demyelinating polyneuropathy

A patient who had a polyneuropathy compatible with a chronic inflammatory demyelinating polyneuropathy and was initially negative for anti-myelin-associated glycoprotein (MAG) antibodies developed a double monoclonal gammopathy, IgM kappa and IgM lambda, two years after the diagnosis. The IgM kappa, but not the IgM lambda, exhibited strong anti-MAG antibody activity. The late appearance of the anti-MAG immunoreactivity suggests that in patients with an initial diagnosis of chronic inflammatory demyelinating polyneuropathy, the search for anti-MAG antibodies should be repeated during the course of the neuropathy.

Sensory neuronopathy and small cell lung cancer: antineuronal antibody reacting with neuroblastoma cells

The anti-Hu antibody is associated with a paraneoplastic subacute sensory neuronopathy (SSN) described in cases of small cell lung cancer (SCLC). The Hu antigen is a pan-neuronal nuclear antigen with a molecular weight of 35-40 kDa. In this study we demonstrated the presence of the paraneoplastic Hu antigen in different neuroblastoma cell lines. We showed that by indirect immunocytochemistry the serum of patients with SSN and SCLC reacts with the nuclei of neuroblastoma cell lines SKN-SH and LAN-1. Western blot analysis of nuclear extracts from neuroblastoma cell lines SKN-SH, IMR-32 and LAN-1 confirmed the presence of the Hu antigen in these neuroblastoma cell lines. By comparing the immunocytochemical method and the Western blot analysis we were able to determine that the Western blot analysis was a more sensitive test. Screening of the sera of a large population (a total of 122 patients with SCLC, 17 with paraneoplastic disorders as well as 121 controls with other neurological disorders) was performed and showed all 5 of the patients with SSN and SCLC to be positive for the anti-Hu antibody, whereas only 11 of the 122 SCLC patients and none of the controls were positive, thereby suggesting that this test has a very high degree of sensitivity.

The T-lymphocyte response against myelin-associated glycoprotein and myelin basic protein in patients with multiple sclerosis

In addition to myelin basic protein (MBP), other minor components of myelin, such as myelin-associated glycoprotein (MAG), may be important autoantigens in MS. To determine whether MAG might be involved in an autoimmune reaction in MS, we screened peripheral blood lymphocytes from MS patients and normal subjects for their sensitization to human MBP and MAG antigen using a [3H]thymidine incorporation assay. We recorded three patterns in MS patients: (1) patients who responded neither to MAG nor to MBP (4/11); (2) patients who responded to both MBP and MAG (5/11); and (3) patients who gave an exclusive response to MAG (2/11). The 10 healthy controls did not respond to either MAG or MBP. That some individuals with MS expressed a specific response against MAG and that more than 50% of MS patients expressed a sensitization to MAG suggest that MAG may have a role in the pathogenesis of MS.

[Autoimmune paraneoplastic neurological syndromes]

Paraneoplastic neurological syndromes are well established causes of neurological dysfunction in cancer patients. Recently an auto-immune origin has been found for the Lambert-Eaton myasthenic syndrome, the subacute sensory neuronopathy of Denny-Brown, the paraneoplastic cerebellar degeneration, the paraneoplastic opsoclonus-myoclonus as well as a few other minor syndromes. Indeed patients suffering from these diseases have been found to produce antibodies directed against the central nervous system. These antibodies can be detected as much as a year before the cancer is found and they are therefore interesting for neurological and oncologic diagnosis.

Inflammatory neuropathy: pathogenesis and clinical features

The nature of the underlying mechanisms in inflammatory and immune-mediated neuropathies continues to represent an intensive area of research. Different auto-antibodies that are thought to cause specific neuropathic syndromes have been described. The involvement of T cells, cytokines, complement and class II molecules in the pathogenesis of these syndromes has also been studied. There is also intensive investigation into the area of immunotherapy, in particular in the use of intravenous immunoglobulin (Ig).

Chlorambucil fails to improve patients with motor neuropathies and antibodies to gangliosides

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Comparison of the N-Linked Oligosaccharide Structures of the Two Major Human Myelin Glycoproteins MAG and P0: Assessment of the Structures Bearing the Epitope for HNK-1 and Human Monoclonal Immunoglobulin M Found in Demyelinating Neuropathy

The epitope for HNK-1 and patient's monoclonal autoantibodies in demyelinating polyneuropathy associated with immunoglobulin M gammopathy is borne by different types of N-linked oligosaccharide structures in human P0 and myelin-associated glycoprotein (MAG). Fourteen glycopeptide fractions bearing different oligosaccharide structures were obtained from either MAG or P0 glycopeptides by serial lectin affinity chromatography on concanavalin A-Sepharose, Phaseolus vulgaris erythrophytohemagglutinin-agarose, Pisum sativum agglutinin-agarose, and Phaseolus vulgaris leucophytohemagglutinin-agarose. As shown by dot-TLC plate immunostaining, the same MAG and P0 glycopeptide fractions were recognized by HNK-1 and patient's immunoglobulin M, confirming that these antibodies display similar specificities. The antigenic carbohydrate was present in glycopeptide fractions that either interact with Pisum sativum agglutinin-agarose or were bound by Aleuria aurantia agglutinin-digoxigenin, indicating that these structures contained alpha(1-6)fucose residues. This study demonstrates that the L2/HNK-1 epitope is borne mainly or even exclusively by N-linked oligosaccharide structures alpha(1-6)fucosylated in the core.

Comparison of the N-Linked Oligosaccharide Structures of the Two Major Human Myelin Glycoproteins MAG and P0: Assessment and Relative Occurrence of Oligosaccharide Structures by Serial Lectin Affinity Chromatography of14C-Glycopeptides

The N-linked oligosaccharide structures of human myelin-associated glycoprotein (MAG) and P0 have been characterized by serial lectin affinity chromatography (SLAC) of 14C-glycopeptides. 14C-Glycopeptides were prepared from purified MAG derivative and P0 by extensive proteolytic digestion and N-14C-acetylation. Assuming that all the 14C-glycopeptides were radiolabelled to the same specific radioactivity, the relative occurrence of the oligosaccharide structures was correlated to the amount of incorporated radioactivity. Sixteen and 15 fractions were generated by SLAC of MAG and P0 14C-glycopeptides, respectively. Despite this tremendous structural heterogeneity, the oligosaccharide "fingerprints" of MAG and P0 obtained by SLAC displayed similarities: (a) of the three types of N-linked oligosaccharides, the complex type accounted for 80.4% and 94.9% of MAG and P0 radioactivity, respectively; (b) biantennary complex oligosaccharides were the major structures present on MAG and P0; (c) approximately 60% of MAG and P0 oligosaccharides possessed a bisecting N-acetylglucosamine residue; and (d) large amounts of oligosaccharides with an alpha(1-6)fucose residue were found in both MAG and P0 and, noticeably, approximately 25% of the tri- and/or tetraantennary and approximately 90% of the bisected biantennary oligosaccharides of both glycoproteins contained alpha(1-6)fucose residues in the core. This study demonstrates that MAG and P0, both belonging to the immunoglobulin superfamily, display structural similarities in their N-linked oligosaccharide contents.

Carbohydrate moieties of myelin-associated glycoprotein, major glycoprotein of the peripheral nervous system myelin and other myelin glycoproteins potentially involved in cell adhesion

The myelin-associated glycoprotein (MAG) and the major glycoprotein of the peripheral nervous system myelin (P0) are two members of the family of cell adhesion molecules (CAMs). A role in cell adhesion of the carbohydrate moiety of these molecules has been attributed to the presence of N-glycans bearing the HNK-1 carbohydrate epitope. On the other hand, it has been suggested that these glycoproteins could be ligands of an endogenous mannose-binding lectin present in myelin, the cerebellar soluble lectin (CSL). In order to further document the heterogeneity of the glycans of these two CAMs, we have used several probes: an anti-carbohydrate antibody of the HNK-1 type, called Elec-39, the plant lectin concanavalin A (ConA), and the endogenous lectin CSL involved in myelin compaction. This study shows that CSL binds to a small proportion of the polypeptide chains of MAG found in adult CNS of rats and man and the polypeptide chains of P0 molecules from adult human and rat sciatic nerve. For MAG from adult rat brain, the binding of CSL is restricted to glycans of polypeptide chains which could be separated from the others according to their solubility properties. These MAG molecular entities react also with the Elec-39 antibody and with ConA. These results confirm that P0 and MAG are heterogeneous in their carbohydrate moieties.(ABSTRACT TRUNCATED AT 250 WORDS)

Borrelia rhombencephalomyelopathy

Three patients, in whom the diagnosis of Borrelia burgdorferi infection was unknown for several years, developed a biphasic involvement of the central nervous system: an acute brain-stem dysfunction was followed up, in two patients, by a progressive, disabling myelitis and, in one patient, by further relapsing-remitting episodes of severe multifocal rhombencephalitis. The most consistent cerebrospinal fluid abnormalities in the analysis of sequential specimens were elevated total IgM levels that normalized after penicillin therapy. The neuropathologic findings in one patient showed microgliosis and meningovascular involvement of the central nervous system, resulting in two ischemic infarcts in the myelencephalon. Few spirochetes were localized in the leptomeninges and around subependymal vessels of the fourth ventricle. The vascular element consisted of an obliterative inflammatory vasculopathy in the medullary parenchyma. This study (1) provides pathologic evidence that a vascular disease induced by B burgdorferi is a pathogenetic mechanism for cerebrovascular diseases, and (2) emphasizes the similarities between neuroborreliosis and neurosyphilis.

Anti-myelin-associated glycoprotein antibodies in patients with a monoclonal IgM gammopathy and polyneuropathy, and a simplified method for the preparation of glycolipid antigens

The two sulfated glucuronic acid containing glycolipids, sulfate-3-glucuronyl paragloboside (SGPG) and sulfate-3-glucuronyl lactosaminyl paragloboside (SGLPG), were prepared by ion exchange chromatography of lipid extracts from bovine cauda equina. Thin layer chromatography (TLC) immunostaining and an enzyme-linked immunosorbent assay (ELISA) were used to show that the SGPG/SGLPG fraction was free of crossreactive antigenic components such as gangliosides. The results obtained by ELISA demonstrate that sera of all patients were validated IgM monoclonal anti-myelin-associated glycoprotein (MAG) demyelinating neuropathy display high titer antibodies with high affinity type titration curves. These antibodies were absent from the sera of 16 patients with other neurological diseases and ten normal controls. ELISA with SGPG/SGLPG as an antigen appears to be a valuable and highly specific immunodiagnostic test for determining anti-MAG antibody titers in the sera of patients. The amount (approximately 0.4 mg) of SGPG/SGLPG partially purified from 10 g of fresh tissue is sufficient for the preparation of approximately 100 96-well plates for ELISA procedures.

[Efficacy and tolerance of cyclosporin A in the treatment of multiple sclerosis]

The use and tolerance of cyclosporine A (Cy A) and azathioprine (AZA) are compared as long-term immunosuppression treatment for multiple sclerosis. 38 patients with multiple sclerosis were randomized and received either Cy A (5 mg/kg/d) or AZA (2 mg/kg/d) during 24 months. These patients were assessed clinically and with different biological parameters. The Cy A blood level was controlled, and Cy A was well tolerated without side effects forcing to stop the treatment. However, its benefits were limited when the different clinical scores are compared.

Predictive value of anti-GM1 ganglioside antibodies in neuromuscular diseases: a study of 180 sera

The incidence of anti-GM1 antibodies in the serum of 104 patients with neurological diseases, 35 patients with non-neurological diseases (NND) and 41 normal controls was determined by enzyme-linked immunosorbent assay (ELISA). Anti-GM1 antibodies were found in 90% of patients presenting with a motor neuropathy (all except one had multifocal conduction blocks). A large proportion (60%) of these patients displayed high antibody titer ranging from 101 to 788. A low incidence of anti-GM1 antibodies was found in the other groups of patients, i.e. 21% of amyotrophic lateral sclerosis (ALS), 26% of other neurological diseases (OND) and 23% of NND. High antibody titers ranging from 106 to 260 were found in two (5%) ALS patients, one (2%) OND patient (myasthenia gravis), and one (3%) NND patient (Waldenström's disease). This study shows that high titers of anti-GM1 antibodies are found in a large proportion of patients with motor neuropathy with multifocal conduction blocks. This argues for a possible autoimmune origin of this neuropathy. We suggest that anti-GM1 antibody determination should be included systematically in the evaluation of all patients with motor neuron diseases and predominantly motor neuropathies.

Serum antibodies to GM1 and GM3-gangliosides in systemic lupus erythematosus with chronic inflammatory demyelinating polyradiculoneuropathy

Acute symmetric demyelinating polyneuropathy of the Guillain-Barré type is known in systemic lupus erythematosus (SLE). Chronic idiopathic demyelinating polyneuropathy (CIDP) has been reported rarely with SLE. A case is reported of CIDP accompanying SLE with autoantibodies against GM1- and GM3-gangliosides. There was no historical evidence to suggest SLE, and CIDP was the first manifestation of SLE. The 38-year-old patient had elevated CSF-protein, slow nerve conduction velocities, sural nerve biopsy revealed mixed axon loss with demyelination and CIDP white matter lesions were observed in magnetic resonance imaging, the GM1- and GM3-autoantibodies may play a role in the pathogenesis of CIDP in SLE.