Serum antibodies to Purkinje cells and dorsal root ganglia neurons in sensory neuronopathy without malignancy

Inflammatory sensory neuronopathies

Inflammatory sensory neuronopathies are rare disorders mediated by dysimmune mechanisms targeting sensory neurons in the dorsal root ganglia. They constitute a heterogeneous group of disorders with acute, subacute, or chronic courses, and occur with cancer, systemic autoimmune diseases, notably Sjögren syndrome, and viral infections but a noticeable proportion of them remains isolated. Identifying inflammatory sensory neuronopathies is crucial because they have the potential to be stabilized or even to improve with immunomodulatory or immunosuppressant treatments provided that the treatment is applied at an early stage of the disease, before a definitive degeneration of neurons. Biomarkers, and notably antibodies, are crucial for this early identification, which is the first step to develop therapeutic trials.

Cerebellar atrophy is infrequently [corrected] associated with non-paraneoplastic sensory neuronopathy

Sensory neuronopathies (SN) are peripheral nervous system disorders associated with degeneration of dorsal root ganglion neurons. Despite the evidence of a defective proprioceptive sensory input in SN,the prominent gait and truncal ataxia raises the question of a concomitant involvement of the cerebellum.

OBJECTIVE

To evaluate cerebellar atrophy in SN.

METHOD

We analyzed MRI-based volumetry of anterior lobe (paleocerebellum) and total cerebellum in patients with non-paraneoplastic chronic SN and compared to age- and gender-matched controls.

RESULTS

Cerebellum and anterior lobe MRI volumetry were performed in 20 patients and nine controls. Mean anterior lobe and cerebellar volume were not statistically different. Three patients (15%), however, had an abnormal anterior lobe and cerebellar volume index (values outside 2.5 standard deviations). One of them also had a specific atrophy of the anterior lobe. All these patients had infectious or dysimmune associated SN.

CONCLUSION

Cerebellar atrophy is infrequently associated with SN, but can be found in some patients with SN related to infectious or immune mediated conditions. It can be more prominent in the anterior lobe and may contribute to the ataxia seen in these patients.

Balance control in Sensory Neuron Disease

OBJECTIVE

Balance control under static and dynamic conditions was assessed in patients with Sensory Neuron Disease (SND) in order to shed further light on the pathophysiology of ataxia.

METHODS

Fourteen patients with diabetic polyneuropathy and 11 with SND underwent clinical and neurophysiological evaluation, stabilometric recording of body sway during quiet stance with and without vision, stereometric analysis of body segment displacement while riding a platform translating in anterior-posterior direction with and without vision (dynamic condition), and EMG recording of leg muscle responses to abrupt stance perturbation produced by rotation of a supporting platform. The findings were compared to those of age matched normal subjects.

RESULTS

Clinical and neurophysiological evaluation revealed a more severe motor impairment in patients with diabetes than SND, while sensory impairment was superimposable. Some patients with SND had vestibular dysfunction of diverse severity. Body sway during stance was larger in patients with SND than diabetes with and without vision. In the stance perturbation condition, the latency of the long-loop EMG response to platform rotation was disproportionately increased with respect to the spinal response in the SND but not in diabetic patients. Under dynamic condition, patients with SND oscillated more than diabetic patients and several of them easily lost balance with eyes closed.

CONCLUSIONS

Patients with SND show severe unsteadiness under both static and dynamic conditions, particularly with eyes closed. The patchy sensory loss of SND, disrupting sensation from territories other than the lower limbs and possibly including the vestibular nerve, could be responsible for this instability. Ataxia is correlated to the abnormal latency of the muscle responses to stance perturbation. Since increased response latencies cannot be attributed to a vestibular deficit, the deterioration of equilibrium control would be ascribed mainly to the degeneration of the central branch of the afferent fibres.

SIGNIFICANCE

Measures of body balance under quiet stance and dynamic conditions can provide relevant diagnostic information as to the pathophysiology and severity of ataxia and viability of the central branch of the sensory fibres, and help in separating patients with peripheral neuropathy from patients with loss of sensory neurones.

The spectrum of antineuronal autoantibodies in a series of neurological patients

The aim of the present study is to identify the range of neurological disorders expressing antineuronal antibodies, evaluate the number of different patterns of reactivity that can be detected, and analyse the contribution of these studies to the identification of subgroups of patients. The records of 882 patients were reviewed and their sera and cerebrospinal fluids tested for antineuronal antibodies. Patients were initially divided into four groups according to suspected clinical diagnosis. Autoantibodies were detected by immunohistochemistry, Western blot of gradient-separated neuronal and recombinant proteins and by RIA. Cerebellar degeneration and sensory neuropathies were the most common neurological disorders in which paraneoplastic-related anti-neuronal antibodies were detected. However, in addition to PCA1/anti-Yo and ANNA1/anti-Hu antibodies, we found other reactivities in six patients with cerebellar degeneration: anti-GAD in three females and atypical in the other cases. The widest range of different anti-neuronal antibodies was detected in patients with peripheral sensory neuropathy. Few patients with Stiff-Person syndrome, temporal lobe epilepsy and myoclonus harboured anti-GAD antibodies. Atypical antibodies were detected in single cases with motor neuron disorder and multiple system atrophy. No anti-neuronal antibodies were detected in patients with neurological complications of connective tissue disorders other than Sjögren's syndrome, or in neurological diseases other than motor neuron disease and multiple system atrophy. Our study shows that the spectrum of neurological disorders in which anti-neuronal antibodies can be detected is wider than previously thought. In addition, we found patterns of neuronal staining and Western blot reactivity that differed from those so far reported. This may permit identification of subgroups of patients in whom strategies directed at removing and/or suppressing antibody production could be of some benefit.

Antibodies to dorsal root ganglia and olfactory cells in a patient with chronic sensory neuropathy and anosmia

We report the case of a 51-year-old woman with anosmia and chronic sensory ataxic neuropathy. Olfactory tests suggested neurosensory anosmia. Immunocytochemical analysis showed serum antibodies against dorsal root ganglion (DRG) cells and olfactory neurons, in the absence of other known causes of anosmia and sensory neuropathy. Clinical and laboratory data suggested a slow autoimmune process affecting dorsal root ganglion and olfactory cells.

Indications for an immune-mediated etiology of idiopathic sensory neuronopathy

To investigate immune mechanisms in the etiology of idiopathic sensory neuronopathy (ISN), we studied neurite outgrowth inhibition and antibody binding to neuronal tissue of serum from 4 patients with ISN. Rat dorsal root ganglion (DRG) cells were cultured in the presence of serum from ISN patients and controls. After 48 h of incubation, neurite outgrowth was quantified with a neurofilament ELISA. Serum from ISN patients significantly inhibited DRG neurite outgrowth compared to controls. ISN serum also strongly immunostained fixed cultured and cryostat rat DRG neurons (at dilutions up to 1:10,240), whereas serum from controls did not. Western blots showed unique binding patterns to DRG proteins in 3 ISN patients compared with controls, but a single band corresponding in all ISN patients was not found. The inhibitory effect of ISN serum on neurite outgrowth and the presence of circulating anti-DRG antibodies in the acute phase of the disease supports an immune-mediated pathogenesis of ISN.

Immunological characterization of a neuronal antibody (anti-Tr) associated with paraneoplastic cerebellar degeneration and Hodgkin's disease

We studied an autoantibody (called anti-Tr), found in the serum and CSF of five patients with paraneoplastic cerebellar degeneration (PCD) and Hodgkin's disease (HD). Anti-Tr antibodies labelled the cytoplasm of Purkinje cells of human and rat cerebellum. The molecular layer of rat cerebellum showed a characteristic dotted pattern suggestive of immunoreactivity of dendritic spines of Purkinje cells. Patients with cerebellar disorders without HD (159) or HD without PCD (30) did not harbor anti-Tr antibodies. Immunoblots of human Purkinje cells or rat and mouse cerebellum were negative. Anti-Tr antibodies, as defined in this study, appear specific for HD-associated PCD. The immunohistochemical pattern described in the rat cerebellum coupled with the absence of reactivity in the immunoblot may be used to identify anti-Tr antibodies.

AAEM case report #31: paraneoplastic sensory neuronopathy

Sensory neuronopathy (SN) presents with sensory ataxia and no weakness. The site of pathology is in the dorsal root ganglia. Electrodiagnostic studies show absence of sensory nerve action potentials and preservation of motor nerve function. Elderly individuals with sensory ataxia and typical electrodiagnostic findings of SN should be evaluated for underlying carcinoma.

Anti-gabaergic neuron autoantibodies in a patient with stiff-man syndrome and ataxia

We describe a patient with autoimmune insulin-dependent diabetes whose original symptoms of trunk stiffness and rigidity of the abdomen were followed three years later by a pancerebellar syndrome. An autoantibody (autoAb) against GABAergic neurons was found in the patient's serum and cerebrospinal fluid (CSF); on Western blot, this autoAb recognized a 64-kDa antigen of cerebellar protein. The detection of this antibody in a case with ataxia suggests that a spectrum of different neurological diseases may be observed in patients harbouring anti-GABAergic neuron autoAb and supports the concept that factors other than autoAb contribute to the clinical presentation of these disorders.

[Electrophysiologic study, diagnosis and cases of acquired sensory polyneuropathy]

Sensory neuropathies encompass a group of neuropathies affecting solely or predominantly peripheral sensory nerves. They are rarely encountered in clinical practice. The authors review sensory nerve conduction studies and compare the various recording technics. Values of compound sensory action potential amplitude and sensory nerve conduction velocity are analyzed. On the basis of clinical and electrophysiological sensory impairment, three types of neuropathies can be proposed: neuropathies with either large, small or total myelinated fibers involvement. Lastly definable causes of sensory neuropathies are reviewed.

Management of painful paraneoplastic syndromes

The majority of patients with advanced malignant disease experience pain, so pain is commonly present in patients with paraneoplastic syndromes. It is rare, however, that the pain itself is a paraneoplastic manifestation of cancer. Usually, the pain in this context is associated with a paraneoplastic syndrome but is not a direct result of that syndrome. Three syndromes in which pain is part of the syndrome and a paraneoplastic manifestation of malignant disease--neuropathy, ganglionitis, and monolitis--have been described in the literature. These syndromes and their management are discussed in this article.

Purification and characterization of natural antibodies that recognize a human brain lectin

We have recently identified oligoclonal IgG antibodies that are related to a human brain lectin (HBL14) from serum and cerebrospinal fluid of patients with neurological disorders. They were termed lectin-like IgG (L-IgG) (Joubert-Caron et al., 1994a,b). In this paper, the occurrence of antibodies reactive both towards HBL14 and L-IgG was investigated. Binding of antibodies to HBL14 was demonstrated by solid-phase ELISA and chromatography on immobilized HBL14. Fab fragments of these antibodies were also shown to bind to HBL14. The specificity of the antibodies towards HBL14 was studied using a panel of different antigens. Our data show that individual sera from healthy people as well as a pool of immunoglobulins from 80 blood donors contain an IgG autoreactivity to HBL14, while no IgM autoreactivity was detected. Anti-HBL14 antibodies from sera were purified using affinity chromatography on immobilized HBL14. Affinity chromatography further allowed us to demonstrate that the binding of anti-HB14 antibodies was mediated through their Fab fragments. A higher amount of anti-HBL14 antibodies was purified using a L-IgG-depleted fraction of sera. The binding of anti-HBL14 antibodies to L-IgG was confirmed by ELISA. Finally, anti-HBL14 antibodies were found to be polyreactive. These results indicate the occurrence of a novel class of natural antibodies reactive towards a human brain lectin and suggest that these antibodies may participate in immunoregulatory mechanisms probably though idiotypic/anti-idiotypic interaction.

Immune diagnosis of paraneoplastic neurological disease

A continuous stream of new information on clinical, pathological and immunological aspects of paraneoplastic neurological syndromes has been published in recent years. In this survey, we will discuss current opinions on the value of anti-neuronal antibody detection for establishing a diagnosis of one of the paraneoplastic syndromes of the central nervous system.