Autoimmunity in paraneoplastic neurological syndromes

Detection of paraneoplastic antibodies and their significance in paraneoplastic neurologic syndromes: a narrative review

Background and Objective

Paraneoplastic neurological syndromes (PNS) are a group of rare syndromes associated with immunopathological process and tumors. Paraneoplastic autoantibodies are important for the diagnosis of PNS and for searching for underlying tumors. With the development of detection methods and discovery of new autoantibodies, the 2004 guidelines on PNS have recently been updated by a worldwide PNS-Care expert group. For clinicians, proper testing methods and testing results explanation are important for the diagnosis and treatment of PNS. This review aims to review the detection of paraneoplastic autoantibodies and the significance of testing results.

Methods

We summarize the studies on detection methods, association of autoantibodies and PNS or tumors, particularly the guidelines of PNS.

Key Content and Findings

Antibodies are divided into 3 groups in the context of PNS according to the frequency of cancer association regardless of their eventual pathogenic effect. Instead of well-characterized antibodies and partially-characterized antibodies, high-risk antibodies, intermediate risk antibodies and lower risk antibodies were applied. According to the location of recognized antigens, these autoantibodies are divided as anti-intracellular antigen antibodies and neuronal surface antibodies (NSAbs). Tissue-based assays is recommended as screening method for paraneoplastic antibodies. Moreover, this method is helpful to discover new autoantibodies. A combination of a screening method [tissue-based assays (TBA)] and a confirmatory test [immunoblot and cell-based assay (CBA)] can improve sensitivity and specificity of the tests. Many PNSs are associated with specific antineuronal antibodies, but there is considerable diversity. Some autoantibodies are markers of specific neurological syndromes. Paraneoplastic antibodies are often specific for the PNS-associated tumor rather than for a particular neurological syndrome.

Conclusions

Diagnosis of PNS depends on integrated analysis of clinical manifestations and auxiliary examinations. During diagnosis, selection of candidate antibodies for testing is challenging due to the varying clinical phenotypes and tumors associated with a given antibody. Broad antibody panels are more likely to capture causative antibodies and should be considered. According to different subtypes of autoantibodies, specific tumors or PNS should be considered. However, antibody titers, including cerebrospinal fluid (CSF) titers, should not be the primary driver of treatment decisions.

Serum Tumor Markers in Paraneoplastic Neurologic Syndromes: A Systematic Review of Guidelines

Purpose: Algorithms for the detection of a malignancy in patients with unclear neurologic symptoms of suspicious paraneoplastic origins are not universally applied. Frequently, circulating tumor markers (TMs) are considered a valuable tool for cancer diagnosis in patients with paraneoplastic neurologic syndromes (PNS). Our aim was to extract the recommendations on the use of TMs and onconeural antibodies (Abs) for the diagnosis of malignancies in PNS from clinical practice guidelines and put them forward as evidence in a common framework to facilitate diffusion, dissemination, and implementation.

Methods: Systematic literature searches were performed for guidelines on both oncology and PNS published since 2007. Guidelines containing information and recommendations for clinical practice pertaining to the screening and diagnosis of PNS were selected. Information on circulating TMs and onconeural Abs was extracted and synthesized in consecutive steps of increasing simplification.

Results: We retrieved 799 eligible guidelines on oncology for the potential presence of information on PNS but only six covered treated diagnosis or the screening of cancer in PNS, which were then selected. Seventy-nine potentially relevant guidelines on PNS were identified as eligible and 15 were selected. Synoptic tables were prepared showing that classical TMs are not recommended for the screening or the diagnosis of a malignancy in patients with a suspected PNS. Neither should onconeural Abs be considered to screen for the presence of a malignancy, although they could be helpful to define the probability of the paraneoplastic origin of a neurologic disorder.

Conclusion: The present work of synthesis may be a useful tool in the diffusion, dissemination, and implementation of guideline recommendations, potentially facilitating the decrease of the inappropriate use of circulating biomarkers for cancer screening in the presence of PNS.

Advances in the Development of Anticancer HSP-based Vaccines

Current advances in cancer treatment are based on the recent discoveries of molecular mechanisms of tumour maintenance. It was shown that heat shock proteins (HSPs) play a crucial role in the development of immune response against tumours. Thus, HSPs represent multifunctional agents not only with chaperone functions, but also possessing immunomodulatory properties. These properties are exploited for the development of HSP-based anticancer vaccines aimed to induce cytotoxic responses against tumours. To date, a number of strategies have been suggested to facilitate HSP-based vaccine production and to increase its effectiveness. The present review focuses on the current trend for the development of HSPbased vaccines aimed at inducing strong immunological tumour-specific responses against cancer cells of distinct etiology and localization.

Immunity and Inflammation in Epilepsy

This review reports the available evidence on the activation of the innate and adaptive branches of the immune system and the related inflammatory processes in epileptic disorders and the putative pathogenic role of inflammatory processes developing in the brain, as indicated by evidence from experimental and clinical research. Indeed, there is increasing knowledge supporting a role of specific inflammatory mediators and immune cells in the generation and recurrence of epileptic seizures, as well as in the associated neuropathology and comorbidities. Major challenges in this field remain: a better understanding of the key inflammatory pathogenic pathways activated in chronic epilepsy and during epileptogenesis, and how to counteract them efficiently without altering the homeostatic tissue repair function of inflammation. The relevance of this information for developing novel therapies will be highlighted.

Treatment for paraneoplastic neuropathies

BACKGROUND

It is not unusual to observe peripheral nervous system involvement in people with tumours outside the nervous system. Any part of the peripheral nervous system can be involved, from sensory and motor neurons to nerve roots and plexuses, from distal trunks to neuromuscular junctions. Pathogenesis also varies from direct infiltration by cancer cells, to treatment toxicity, to metabolic derangement, cachexia, infections and paraneoplastic syndromes.Paraneoplastic neurological syndromes are symptoms or signs resulting from damage to organs or tissues that are remote from the site of the malignancy or its metastases. The pathogenesis is thought to be immune-mediated as a result of a cross-reaction against antigens shared by the tumour and nervous system cells.Paraneoplastic neuropathies are the most frequently reported paraneoplastic syndromes. They are, however, heterogeneous and require several therapeutic approaches. This review was undertaken to systematically assess any data available from randomised controlled trials (RCTs) on the treatment of paraneoplastic syndromes of the peripheral nervous system and not the whole range of paraneoplastic neurological syndromes.

OBJECTIVES

To assess the benefits and harms of treatments for paraneoplastic neuropathies.

SEARCH METHODS

We searched the Cochrane Neuromuscular Disease Group Specialized Register (14 February 2012), CENTRAL (2012, Issue 1), MEDLINE (January 1966 to February 2012), EMBASE (January 1980 to February 2012) and LILACS (January 1982 to February 2012) for RCTs, quasi-RCTs, historically controlled studies and trials with concurrent controls.We adapted this strategy to search MEDLINE from 1966 and EMBASE from 1980 for comparative cohort studies, case-control studies and case series.

SELECTION CRITERIA

We planned to include all RCTs and quasi-RCTs (in which allocation is not random but is intended to be unbiased, for example alternate allocation) of any treatment for paraneoplastic neuropathies. Since we expected there to be few or no included studies, we also planned to assess and summarise observational studies, prospective and retrospective comparative cohort studies, case-control studies and case series that met minimum criteria in the discussion.

DATA COLLECTION AND ANALYSIS

Three review authors selected the trials for inclusion. When there was any disagreement we reached an agreement by discussion. Two review authors extracted data independently onto a specially designed data extraction form. We would have collected adverse event data from included studies.

MAIN RESULTS

Despite many reports on paraneoplastic neuropathy, we identified no RCT or quasi-RCTs for inclusion in this review. We found only six studies, involving 54 participants, from among the non-randomised evidence that were judged by predefined criteria to be of suitable quality for inclusion in the discussion. These studies were not readily comparable. The treatments focused on tumour treatment and immunomodulation, mainly intravenous immunoglobulin.

AUTHORS' CONCLUSIONS

At present there are no RCTs or quasi-RCTs of treatment for paraneoplastic neuropathies on which to base practice. There is only evidence from case series, case reports or expert opinion (class IV evidence) for the effect of immunomodulation (intravenous immunoglobulin, plasma exchange, steroid treatment or chemotherapy) on paraneoplastic neuropathy.  

Endometrial carcinoma presenting as vasculitic sensorimotor polyneuropathy

Paraneoplastic syndromes (PNS) are a heterogeneous group of symptoms which are indirectly caused by primary or metastatic tumor. Paraneoplastic polyneuropathy (PNP) is mostly related to small cell lung cancer (5%), prostate, gastric, and breast cancer. Only sporadic cases have been reported to be associated with endometrial cancer. We present a case of a premenopausal woman with severe vasculitic, asymmetric sensorimotor polyneuropathy that developed in conjunction with an endometrial carcinoma responding to surgical therapy of primary tumor combined to steroid therapy. Neurological symptoms such as asymmetrical sensorimotor deficits and painful paresthesias are suspicious when they occur in otherwise healthy women with no medical history. The phenomenon of a paraneoplastic syndrome can point to an underlying malignancy and can be used as marker of progression or regression of the tumor. Due to the rarity of PNP, there is no standard treatment. Recommended therapy is stage-adjusted treatment of the primary tumor.

Autoantibodies in childhood opsoclonus-myoclonus syndrome

Opsoclonus-myoclonus syndrome or Dancing Eye Syndrome (OMS/DES) is a rare neurological disorder of children, which associates with neuroblastoma (NB) in approximately 50% of cases. We examined sera from five patients with (OMS-NB(+)) and five without NB (OMS-NB(-)) for autoantibodies. OMS-NB(-) IgG bound to the surface of a NB cell line, whereas IgG from OMS-NB(+) and from NB patients without OMS/DES bound only to permeabilised cells. Both OMS-NB(+) and OMS-NB(-) reduced proliferation of NB cells. We also present a case report of a child with OMS/DES without NB who made a complete recovery without treatment. Serum antibodies at presentation bound to the surface and decreased NB cell proliferation but had decreased 9 weeks later when the child was asymptomatic. These results demonstrate that sera from some OMS/DES patients contain IgG antibodies that are potentially pathogenic.

Qualitative evidence of Ri specific IgG-synthesis in the cerebrospinal fluid from patients with paraneoplastic neurological syndromes

The presence of Ri-specific oligoclonal IgG bands in the CSF was investigated in five patients with paraneoplastic anti-Ri associated neurological syndromes (PNS) and six controls. In 4/5 CSF samples reactivity of IgG bands with recombinant Ri antigen was found using isoelectrofocusing combined with affinity blotting; in one patient with absence of oligoclonal bands of total IgG in CSF Ri-specific oligoclonal bands were detected with the same sample, indicating a higher sensitivity of Ri-specific affinity blotting as compared to affinity blotting with anti-human IgG antibodies. Our results confirm previous studies demonstrating IgG synthesis against onconeuronal antigens by intrathecal B-cell clones in PNS and extend this observation to patients with anti-Ri syndrome. The pathogenic relevance of these antibodies, however, is further challenged by the finding that specific intrathecal IgG synthesis might not be a prerequisite of CNS involvement, because it was missed in one of our patients.

Brain iron metabolism: neurobiology and neurochemistry

New findings obtained during the past years, especially the discovery of mutations in the genes associated with brain iron metabolism, have provided key insights into the homeostatic mechanisms of brain iron metabolism and the pathological mechanisms responsible for neurodegenerative diseases. The accumulated evidence demonstrates that misregulation in brain iron metabolism is one of the initial causes for neuronal death in some neurodegenerative disorders. The errors in brain iron metabolism found in these disorders have a multifactorial pathogenesis, including genetic and nongenetic factors. The disturbances of iron metabolism might occur at multiple levels, including iron uptake and release, storage, intracellular metabolism and regulation. It is the increased brain iron that triggers a cascade of deleterious events, leading to neuronal death in these diseases. In the article, the recent advances in studies on neurochemistry and neuropathophysiology of brain iron metabolism were reviewed.

Epilepsy and the immune system: is there a link?

The concept that the immune system plays a role in the epileptogenic process of some epileptic syndromes was first proposed more than 20 years ago. Since then, numerous studies have reported on the existence of a variety of immunological alterations in epileptic patients, on the observation of favourable responses of refractory epilepsy syndromes to immunomodulatory treatment, and on the association of certain well-known immune-mediated disease states with epilepsy. This review comprehensively recapitulates the currently available evidence supporting or arguing against the possible involvement of the immune system in the pathogenesis of certain types of epilepsy. It is concluded that an abundance of facts is in support of this concept and that further studies should be directed at substantiating the pathogenic significance of (auto)immune responses in certain types of epilepsy. Current progress in the functional and molecular immunological research techniques will indisputably contribute to the elucidation of this link.

Gangliosides act as onconeural antigens in paraneoplastic neuropathies

We describe two patients with progressive neuropathy and lung cancer in whom gangliosides (GS) may represent the oncoantigens. Patient 1 had motor neuropathy, high titers of IgG1 and IgG3 to GD1a and GM1, and expansion of circulating gamma-delta T lymphocytes, a T-cell subset responding to glycolipids. Patient 2 presented with Miller-Fisher-like syndrome and IgG3 activity to disialo-GS. In both cases, decreased autoimmune responses and stabilization of neuropathy were accomplished by tumor treatment. By immunohistochemistry, patient 1's IgG bound to his own tumor and to structures of normal nervous system expressing GD1a or GM1. Infiltration of IgG in the same neural structures was found at his autopsy. Regarding cellular immunity, the proportion of gamma-delta T lymphocytes infiltrating carcinoma from patient 1 was significantly higher than in neoplastic controls. These results indicate that GS may represent onconeural antigens in paraneoplastic neuropathy (PNN); their expression on neoplastic tissue may elicit autoimmune responses, which also target neural structures.

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.

Complicated paraneoplastic neurological syndromes: a report of two patients with small cell or non-small cell lung cancer

Paraneoplastic neurological syndromes are frequently associated in patients with small cell lung cancer (SCLC) and antineuronal antibodies are involved in the autoimmune mechanism. Multiple syndromes are sometimes complicated in a single patient with SCLC. However, little is known about non-SCLC-associated neurological manifestations. We report two patients with complicated paraneoplastic neurological syndromes. Patient 1 showed paraneoplastic limbic encephalitis (PLE), paraneoplastic sensory neuropathy (PSN) and Lambert-Eaton myasthenic syndrome (LEMS) associated with SCLC. Patient 2 developed opsoclonus-ataxia and probable PLE associated with non-SCLC. Analysis of various antineuronal antibodies revealed that anti-Hu and P/Q-type voltage-gated calcium channel (VGCC) antibodies were positive in Patient 1 but any antibodies were not in Patient 2. Brain MRI demonstrated high intensity signals in temporal lobes particularly on fluid-attenuated inversion recovery (FLAIR) or diffusion-weighted images. These findings suggest that complicated paraneoplastic neurological syndromes occur in non-SCLC as well as SCLC and that unidentified antineuronal autoantibodies may underlie the pathophysiology.

Paraneoplastic neurological disorders in breast cancer

Paraneoplastic syndromes are the rarest neurological complications in patients with cancer. The neurological paraneoplastic syndromes that are mainly associated with breast cancer are subacute cerebellar degeneration, paraneoplastic retinopathy, opsoclonus-myoclonus syndrome, lower motor neuron diseases and Stiff-man syndrome. The aim of this paper is to briefly outline these paraneoplastic neurological syndromes and consider their relation to breast carcinoma.

A novel frozen brain tissue array technique: immunohistochemical detection of neuronal paraneoplastic autoantibodies

We introduce a modification of the tissue microarray technique in which several frozen brain tissue specimens are collected to a single frozen brain array block. In the present application, we use it for the detection of neuronal paraneoplastic anti-Hu autoantibodies. Representative samples from 15 different brain regions were collected according to a standard neuropathological autopsy protocol. Cryostat sections from each block were cut and conventionally stained. From representative areas, cylinder tissue samples from each specimen were punched and then arrayed into a recipient array block. Using the cryostat sections of this brain array, autoantibodies from seven anti-Hu-positive patient sera (confirmed by immunoblotting) were screened by immunohistochemistry. Neuronal architecture was well preserved and immunohistochemical staining was comparable to that of conventional cryostat sections. Because of the variable staining pattern in different brain areas, two anti-Hu-positive sera could be detected immunohistochemically by the one brain array. With the present array technique, it is possible to characterize the variable staining patterns of neuronal paraneoplastic autoantibodies in different locations of the human brain. The frozen brain array also allows the detection of RNA and DNA targets involved in neurological diseases.

Qualitative evidence of anti-Yo-specific intrathecal antibody synthesis in patients with paraneoplastic cerebellar degeneration

We investigated the presence of anti-Yo-specific oligoclonal antibody bands in cerebrospinal fluid (CSF) and serum samples of 9 patients with anti-Yo syndrome and 11 controls. Isoelectric focusing combined with affinity blotting, revealed anti-Yo-specific intrathecal antibody synthesis in all patients with anti-Yo syndrome: Four patients had positive anti-Yo-specific oligoclonal IgG bands in CSF which were not demonstrable in their sera; five CSF/serum pairs showed additional, more intensive, oligoclonal bands in CSF compared to the corresponding serum. Interestingly, four patients with absence of oligoclonal bands of total IgG in CSF revealed positive anti-Yo-specific oligoclonal bands in the same sample. This speaks for a higher sensitivity of detection of oligoclonal bands using an affinity blot loaded with Yo-specific antigen compared to an affinity blot coated with anti-human IgG used for the detection of oligoclonal bands of total IgG. In conclusion, the presence of anti-Yo-specific oligoclonal IgG bands in CSF which were absent, or less strong, in patients sera provides qualitative evidence of anti-Yo-specific IgG synthesis by intrathecal B-cell clones. These results could be of interest in detection of intrathecal-specific IgG synthesis in nervous system infectious diseases provided that the target antigen is known.

Paraneoplastic neurological syndromes: an update on diagnosis, pathogenesis, and therapy

Since the discovery of the first clinically relevant anti neuronal antibody specific for a paraneoplastic aetiology in 1985, the number of such reactivities has grown at a rate of about one per year. Clinicians can now diagnose a paraneoplastic syndrome much more easily. This ability is especially important because, typically, the neurological symptoms occur before the cancer is diagnosed. Early tumour diagnosis is essential, because effective treatment of the cancer still seems to be the most efficient treatment option for the neurological symptoms. Immuno modulatory therapy should, nevertheless, be initiated as early as possible and seems especially helpful for peripheral syndromes and limbic encephalitis. The recent fundamental advances in understanding of the autoimmune pathology of these disorders, especially the role of cytotoxic T cells, should eventually lead to more effective treatment options.

Occult Small Cell Lung Cancer Associated with Paraneoplastic Neurologic Syndrome: Case Report

Cancer is often associated with paraneoplastic syndromes, which may be misinterpreted. We report a case of a patient with occult small cell lung cancer that was initially compounded by clinical features of a paraneoplastic neurologic syndrome. The presence of antineuronal antibodies and positron emission tomography scan guided the search for the underlying tumor.

Following chemo-radiotherapy the patient showed no evidence of disease for the next 18 months, whereas only a slight improvement in the neurologic disorders was observed. The course of the small cell lung cancer was very indolent and the paraneoplastic neurologic syndrome did not worsen with the use of cisplatin.

Paraneoplastic neurological syndromes - patients' cohort profile in the Czech Republic

Reported paraneoplastic neurological syndromes (PNS) are rare disabling neurological diseases with supposed autoimmune pathogenesis. The aims of this study were to evaluate frequency, clinical course and therapeutic response in the cohort of PNS positive patients (n=10) in the Czech Republic for the first time. Second, we determined the presence and distribution of oligoclonal IgG bands (OB IgG) in PNS and compared the clinical and laboratory features of OB IgG positive and negative patients. A total of 2355 suspicious serum and/or CSF samples were screened by immunofluorescence and immunohistochemistry with definite confirmation by Western blot. OB IgG were detected by isoelectric focusing and immunoenzymatic staining and clinical status was scored according to modified Rankin scale (RS). Four patients had anti-Yo antibody, ovarian cancer and the score in range (2-5) on RS. Five patients had anti-Hu antibody, small cell lung cancer (SCLC), prostate cancer and the score between 1-4 grade on RS. One patient with SCLC and anti-Ri antibody had grade 2. Five of 10 patients with PNS had positive OB IgG and average value 4.2 on RS comparing with negative OB IgG patients with average value 2.6. Finally, we add well-defined cohort of PNS patients to emerging European profile of PNS and conclude that the presence of OB IgG in PNS seems to reflect enhanced immune response with more severe neurological damage and clinical course.

Synapsin I Identified as a Novel Brain-Specific Autoantigen

BACKGROUND

We report the identification and characterization of a novel 74-kd brain-specific autoantigen that is reactive with serum from a patient with discoid lupus erythematosus and chronic lymphocytic leukemia.

METHODS

We determined the molecular weight, tissue distribution and subcellular distribution of the autoantigen and obtained limited amino acid sequence after purification by ion-exchange chromatography and trypsin digestion.

RESULTS

We identified the 74-kd autoantigen as synapsin I on the basis of the following observations. First, the autoantigen has properties consistent with synapsin I: molecular weight of approximately equals 74 kd, brain-specific distribution, presence in cytosol and on synaptosomes, and association with taxol-stabilized microtubules. Second, limited amino acid sequence determination after trypsin digestion of the autoantigen shows identity with synapsin I. Third, the autoimmune serum immunoblots fusion proteins that incorporate rat synapsin Ia. The autoantibodies reactive to synapsin Ia are of immunoglobulin (Ig) G and IgM class.

CONCLUSIONS

This is the first report of autoantibodies that are reactive to synapsin Ia. Autoantibodies that are reactive to synapsin Ia are not restricted to discoid lupus erythematosus patients, because we found identical reactivity in two of 18 sera from dsDNA-positive systemic lupus erythematosus patients and in two of 14 rheumatoid factor-positive sera. Whether autoantibodies to synapsin I are associated with neuropsychiatric manifestations is currently unknown.

Restricted IgG1 subclass of anti-Yo antibodies in paraneoplastic cerebellar degeneration

Paraneoplastic cerebellar degeneration (PCD) occurs as a non-metastatic manifestation of cancer in a small proportion of patients with certain breast or gynaecological tumours, and is characterised by widespread Purkinje cell loss. Antibodies against a Purkinje cell cytoplasmic antigen, called Yo, that is expressed by the tumours, are present in the majority of these patients, but the pathogenic role of the antibodies is not clear. To characterise further the immune response in these cases, 13 anti-Yo positive sera were tested for IgG subclasses by immunohistochemistry and western blotting and, in four cases, PHA-stimulated cytokine secretion by peripheral blood lymphocytes was measured. Surprisingly, anti-Yo antibodies were entirely restricted to the IgG1 subclass, whereas antibodies against the small cell cancer-associated antigen, Hu, were found in all four IgG subclasses. There was a trend towards raised IgG1 levels in the total IgG of the anti-Yo positive patients and, in two, PHA-stimulated peripheral blood lymphocytes secreted raised levels of IFN-gamma. By contrast, in the other two cases tested, raised levels of IL-4 were secreted. Patients with PCD associated with anti-Yo antibodies appear to have strong immune responses that are polarised with respect to the IgG subclass and Th cytokine profiles.

EFNS task force report: a questionnaire-based survey on the service provision and quality assurance for determination of diagnostic autoantibody tests in European neuroimmunology centres. European Federation of Neurological Societies

Autoantibodies to a wide variety of neural components are frequently sought in the sera of patients with neurological diseases suspected to have an antibody-associated autoimmune basis. Variations in assay methodology and availability are likely to exist throughout European diagnostic immunology centres, and interlaboratory discrepancies in performance for some assays have been reported. The availability of quality assurance is largely unknown. In this questionnaire-based EFNS task force, all 18 national representatives of the Neuroimmunology Panel within the EFNS were invited to estimate the service provision within their country; 12 panel members responded. From these responses, it emerged that a range of assays are being performed throughout European centres, involving over 20 separate antigens, using a broad array of immunodetection techniques. With the exception of the estimation of anti-AChR antibodies for the diagnosis of myasthenia gravis, no systematic quality assurance schemes are available, this being conducted on an ad hoc basis, or not at all. Since quality is a central component of assay sensitivity and specificity, we conclude that there is an urgent need to introduce pan-European quality assurance schemes, based on provision of positive and negative test sera from a central source, and in which all neuroimmunology laboratories should participate.

Inflammatory neuropathies: update

This review focuses on recent neuroimmunological findings in autoimmune inflammatory neuropathies. In Guillain-Barré syndrome and paraneoplastic neuropathy most current investigations are centred on the hypothesis of molecular mimicry. In chronic inflammatory demyelinating polyradiculoneuropathy and multifocal motor neuropathy the data on immunopathology are more fragmentary. Why and how patients with autoimmune inflammatory neuropathies raise an increased anti-self-reactivity and how this leads to disease remains a major challenge for future research.

Pathogenic autoantibodies to neuronal proteins in neurological disorders

Autoantibodies to acetylcholine receptors and to voltage-gated calcium and potassium channels are thought to be pathogenic in three peripheral neurological disorders: myasthenia gravis, the Lambert Eaton syndrome and acquired neuromyotonia. However, evidence for the role of antibodies in conditions involving the central nervous system, is scanty or unclear. This review describes the ways in which the roles of autoantibodies have been defined in the peripheral diseases, and discusses the more controversial evidence for involvement of autoantibodies in some central disorders such as multiple sclerosis.