An uncontrolled trial of rituximab for antibody associated paraneoplastic neurological syndromes

'Medusa head ataxia': the expanding spectrum of Purkinje cell antibodies in autoimmune cerebellar ataxia. Part 3: Anti-Yo/CDR2, anti-Nb/AP3B2, PCA-2, anti-Tr/DNER, other antibodies, diagnostic pitfalls, summary and outlook

Serological testing for anti-neural autoantibodies is important in patients presenting with idiopathic cerebellar ataxia, since these autoantibodies may indicate cancer, determine treatment and predict prognosis. While some of them target nuclear antigens present in all or most CNS neurons (e.g. anti-Hu, anti-Ri), others more specifically target antigens present in the cytoplasm or plasma membrane of Purkinje cells (PC). In this series of articles, we provide a detailed review of the clinical and paraclinical features, oncological, therapeutic and prognostic implications, pathogenetic relevance, and differential laboratory diagnosis of the 12 most common PC autoantibodies (often referred to as 'Medusa head antibodies' due to their characteristic somatodendritic binding pattern when tested by immunohistochemistry). To assist immunologists and neurologists in diagnosing these disorders, typical high-resolution immunohistochemical images of all 12 reactivities are presented, diagnostic pitfalls discussed and all currently available assays reviewed. Of note, most of these antibodies target antigens involved in the mGluR1/calcium pathway essential for PC function and survival. Many of the antigens also play a role in spinocerebellar ataxia. Part 1 focuses on anti-metabotropic glutamate receptor 1-, anti-Homer protein homolog 3-, anti-Sj/inositol 1,4,5-trisphosphate receptor- and anti-carbonic anhydrase-related protein VIII-associated autoimmune cerebellar ataxia (ACA); part 2 covers anti-protein kinase C gamma-, anti-glutamate receptor delta-2-, anti-Ca/RhoGTPase-activating protein 26- and anti-voltage-gated calcium channel-associated ACA; and part 3 reviews the current knowledge on anti-Tr/delta notch-like epidermal growth factor-related receptor-, anti-Nb/AP3B2-, anti-Yo/cerebellar degeneration-related protein 2- and Purkinje cell antibody 2-associated ACA, discusses differential diagnostic aspects and provides a summary and outlook.

Paraneoplastic neuropathies

PURPOSE OF REVIEW

This article provides an approach to the recognition and management of paraneoplastic neuropathies.

RECENT FINDINGS

Paraneoplastic neuropathies may have unique phenotypic presentations, such as sensory neuronopathy, autonomic enteric neuropathy, demyelinating neuropathy, and, rarely, motor neuropathy. Paraneoplastic sensorimotor neuropathy, on the other hand, may be indistinguishable from other common types of axonal polyneuropathy. Certain patterns of neuropathies are commonly seen with different types of cancers, but this relationship is not exclusive and not all patients whose pattern of neuropathy suggests a paraneoplastic disorder have an underlying cancer. In addition to definitive therapy for malignancy, immunomodulatory therapy, such as corticosteroids, IV immunoglobulin (IVIg), or immunosuppressants, may benefit some patients, but there are very few published treatment data for paraneoplastic neuropathies.

SUMMARY

Prompt recognition of paraneoplastic neuropathies may lead to identification and treatment of an occult cancer. Treatment can potentially arrest the progression of neuropathy.

Autoimmune channelopathies in paraneoplastic neurological syndromes

Paraneoplastic neurological syndromes and autoimmune encephalitides are immune neurological disorders occurring or not in association with a cancer. They are thought to be due to an autoimmune reaction against neuronal antigens ectopically expressed by the underlying tumour or by cross-reaction with an unknown infectious agent. In some instances, paraneoplastic neurological syndromes and autoimmune encephalitides are related to an antibody-induced dysfunction of ion channels, a situation that can be labelled as autoimmune channelopathies. Such functional alterations of ion channels are caused by the specific fixation of an autoantibody upon its target, implying that autoimmune channelopathies are usually highly responsive to immuno-modulatory treatments. Over the recent years, numerous autoantibodies corresponding to various neurological syndromes have been discovered and their mechanisms of action partially deciphered. Autoantibodies in neurological autoimmune channelopathies may target either directly ion channels or proteins associated to ion channels and induce channel dysfunction by various mechanisms generally leading to the reduction of synaptic expression of the considered channel. The discovery of those mechanisms of action has provided insights on the regulation of the synaptic expression of the altered channels as well as the putative roles of some of their functional subdomains. Interestingly, patients' autoantibodies themselves can be used as specific tools in order to study the functions of ion channels. This article is part of a Special Issue entitled: Membrane channels and transporters in cancers.

T cells targeting a neuronal paraneoplastic antigen mediate tumor rejection and trigger CNS autoimmunity with humoral activation

Paraneoplastic neurologic diseases (PND) involving immune responses directed toward intracellular antigens are poorly understood. Here, we examine immunity to the PND antigen Nova2, which is expressed exclusively in central nervous system (CNS) neurons. We hypothesized that ectopic expression of neuronal antigen in the periphery could incite PND. In our C57BL/6 mouse model, CNS antigen expression limits antigen-specific CD4+ and CD8+ T-cell expansion. Chimera experiments demonstrate that this tolerance is mediated by antigen expression in nonhematopoietic cells. CNS antigen expression does not limit tumor rejection by adoptively transferred transgenic T cells but does limit the generation of a memory population that can be expanded upon secondary challenge in vivo. Despite mediating cancer rejection, adoptively transferred transgenic T cells do not lead to paraneoplastic neuronal targeting. Preliminary experiments suggest an additional requirement for humoral activation to induce CNS autoimmunity. This work provides evidence that the requirements for cancer immunity and neuronal autoimmunity are uncoupled. Since humoral immunity was not required for tumor rejection, B-cell targeting therapy, such as rituximab, may be a rational treatment option for PND that does not hamper tumor immunity.

7th International Immunoglobulin Conference: Interlaken Leadership Awards

The Interlaken Leadership Awards (ILAs), established in 2010, are monetary grants pledged annually by CSL Behring to fund research into the use of immunoglobulin (Ig) therapy, especially into its use in neurological disorders. Five recipients of the 2011/2012 Awards were invited to present their research at the 7th International Immunoglobulin Conference. Dr Honnorat reports on paraneoplastic neurological syndromes (PNS). His multi-centre Phase II trial, currently under way, will assess the efficacy of IVIg therapy in treating PNS in the first 3 months of treatment. Dr Geis shows improved disease scores after IVIg treatment in a mouse model of neuromyelitis optica (NMO). It is hoped that these promising results will translate well into human NMO. Dr Schmidt studied IVIg therapy in an mdx mouse model for Duchenne muscular dystrophy (DMD). He reports that motor function improved and myopathic changes in skeletal muscles and creatine kinase release were decreased. Dr Gamez presents the design and rationale for a Phase II clinical trial investigating the preoperative use of IVIg therapy in myasthenia gravis patients to prevent post-operative myasthenic crisis. Dr Goebel reports results from studies elucidating the immune-mediated pathogenesis of complex regional pain syndrome (CRPS), the successful IVIg therapy in a proportion of CRPS patients, and the development of a model for predicting which patients are more likely to respond to Ig therapy.

Therapeutic approaches in antibody-associated central nervous system pathologies

Initially, antibodies targeting intracellular compounds were described in patients with paraneoplastic neurological syndromes (PNS) such as anti-Hu, anti-Yo, anti-Ri or anti-CV2/CRMP5 antibodies. As more than 90% of patients with these antibodies suffer from an associated cancer, these antibodies were used as biomarkers of an underlying tumour. Recently, autoantibodies targeting cell-surface synaptic antigens have been described in patients with neurological symptoms suggesting PNS. These autoantibodies being less frequently associated with a tumour, they completely changed the concept of PNS. They lead to a new classification, not based on clinical symptoms or oncological status but on the location of the targeted antigens. Three groups of autoantibodies can be delineated according to the neuronal localization of the targeted antigen: Group 1: cytoplasmic neuronal antigens (CNA) (anti-Hu, Yo, CV2/CRMP5, Ri, Ma1/2, Sox, Zic4). Group 2: cell-surface neuronal antigens (CSNA) (anti-NMDAR, Lgi1, CASPR2, VGCC, AMPAr, GlyR, DNER, GABABR, GABAAR, IgLONS, mGluR1 and mGluR5). Group 3: intracellular synaptic antigens (ISA) (anti-GAD65 and anti-amphiphysin). More than being solely a classification of patients, these three groups are related to profound differences in the pathophysiology and in the pathogenic role of the associated autoantibody. According to the type of associated autoantibody, the age and sex of patients, physicians are now able to predict the presence or absence of tumour, the clinical evolution and prognostic and also the response to immunomodulator treatments that differ fundamentally from one group to the others.

Diagnosis and management of paraneoplastic neurologic disorders

OPINION STATEMENT

Paraneoplastic neurologic disorders (PND) are a heterogeneous group of immune-mediated neurological disorders associated with systemic cancers. When a PND is diagnosed, prompt identification and treatment of the associated tumor is important as PND stabilization and in some cases improvement have been reported after tumor treatment. The cancer, however, may be small and difficult to detect or the onset of the PND may precede the development of the cancer by months or years. In the latter cases, patients often initially present to neurologists or internists who will need assistance from their oncology colleagues to uncover the cancer. It is therefore important to be aware of the associations of common cancers with specific PND syndromes and the significance in some PND of the presence in serum and/or cerebrospinal fluid (CSF) of specific antineuronal antibodies. Together, this information can focus the search for the tumor or support continued vigilance. Previously thought to be poorly responsive to therapies, it is now recognized that there is a subgroup of PND, mostly associated with antibodies to antigens on the neuronal cell surface that are highly treatment responsive. Treatments aimed at the PND are mostly immunosuppressive and include corticosteroids, plasma exchange and intravenous immunoglobulins (IVIg). Immunosuppressive chemotherapeutics and B-cell targeting drugs such as rituximab also may be useful. Although cancer patients tolerate these therapies, there is the risk of increased toxicity when combined with tumor-directed treatments and treatment plans should be coordinated between specialists.

A prospective open-label study of sirolimus for the treatment of anti-Hu associated paraneoplastic neurological syndromes

BACKGROUND

Several lines of evidence suggest a T cell-mediated immune response in paraneoplastic neurological syndromes with anti-Hu antibodies (Hu-PNS). In order to investigate whether suppression of T cell-mediated immune responses in Hu-PNS patients improved their neurological outcome, we performed a prospective open-label, single-arm study on sirolimus.

METHODS

Seventeen progressive Hu-PNS patients were treated with sirolimus with an intended treatment duration of 8 weeks. Primary outcome measures were (i) functional improvement, defined as a decrease of one or more points on the modified Rankin Scale (mRS), and (ii) improvement of neurological impairment, defined as an increase of one or more points on the Edinburgh Functional Impairment Tests (EFIT).

RESULTS

One patient showed improvement on both clinical scales (mRS and EFIT). This patient presented with limbic encephalitis and improved dramatically from an mRS score of 3 to mRS 1. Another patient, with subacute sensory neuronopathy, remained stable at mRS 2 and improved one point on the EFIT scale. The other patients showed no improvement on the primary outcome measures. Median survival was 21 months.

CONCLUSION

We conclude that treatment of Hu-PNS patients with sirolimus may improve or stabilize their functional disabilities and neurological impairments. However, the effects of this T cell-targeted therapy were not better than reported in trials on other immunotherapies for Hu-PNS. Trial Registration https://www.clinicaltrialsregister.eu/ctr-search/trial/2008-000793-20/NL.

Paraneoplastic cerebellar degeneration as the first evidence of malignancy: a case report

Paraneoplastic cerebellar degeneration (PCD) is an immune-mediated paraneoplastic disorder affecting the cerebellum. PCD associated with ovarian malignancy is a rare occurrence with fewer than 100 cases reported in published work. PCD patients express anti-Yo antibody, one of the anti-onconeuronal antibodies which is most likely associated with gynecologic or breast malignancies. In this report, we present the case of a 65-year-old postmenopausal woman presenting with acute symptoms of PCD as a first sign of ovarian malignancy.

Experience with low-dose rituximab in off-label indications at two tertiary hospitals

BACKGROUND

Rituximab is a monoclonal antibody directed against B cells and is increasingly used to treat a variety of autoimmune conditions. Most published evidence reporting the successful use of rituximab in off-label indications has empirically used a high-dose regimen (either 375 mg/m(2) weekly for 4 weeks, or 1000 mg × 2), which is the approved course of treatment for lymphoma and rheumatoid arthritis patients.

AIMS

The aims of this report are to review the indications, outcomes and adverse events of low-dose (500 mg twice, given 1-2 weeks apart), off-label use of rituximab in our institutions, and to review the available evidence.

METHODS

We performed a retrospective audit of the off-label use of low-dose rituximab at two university teaching, tertiary referral hospitals, from mid-2008 until the end of 2011.

RESULTS

Off-label rituximab was given to 52 patients (53 indications) across a heterogeneous group of autoimmune conditions. Outcomes were known for 46 conditions (affecting 45 patients), and of these, complete responses were observed in 16 (35%) conditions and a further 19 (41%) had a partial response. There was no response to rituximab in 11 (24%) patients. There were eight significant adverse events, mostly related to infectious complications.

CONCLUSION

This case series suggests that low-dose courses of rituximab can be used off-label to treat several severe and/or refractory immunological disorders with a reasonable safety profile; however, further trials are required in many off-label indications.

Antiglycine receptor antibody and encephalomyelitis with rigidity and myoclonus (PERM) related to small cell lung cancer

A 39-year-old man (a lifetime non-smoker) presented with a locked left jaw and leg myoclonus. Clinical and electromyographic findings were in keeping with progressive encephalomyelitis with rigidity and myoclonus (PERM) syndrome. A thoracic CT scan demonstrated a 19 mm right hilar nodule, which was proven to be small cell lung cancer on bronchoscopic biopsy. Serological evaluation of the patient's plasma revealed antibodies against glycine receptors (serology negative for anti-GAD, anti-Yo, anti-Hu, anti-Ri, antiamphiphysin, anti-Ma2/Ta, anti-CRMP5 and anti-NMDA receptor). After his cancer was treated with chemotherapy and intravenous immunoglobulins (IVIg), neurological symptoms resolved but returned several months later without any evidence of cancer recurrence. Symptoms were refractory to corticosteroids and IVIg therapy. Rituximab was then initiated, which led to a dramatic and sustained resolution of symptoms. To our knowledge, this is the first case of PERM related to antiglycine receptor antibodies from paraneoplastic syndrome, which resolved with rituximab.

Anti-Yo mediated paraneoplastic cerebellar degeneration in the context of breast cancer: a case report and literature review

BACKGROUND

Paraneoplastic syndromes are of interest to psycho-oncologists because they may be misdiagnosed initially as primary psychiatric disorders and can have profound neuropsychiatric and psychosocial sequelae. Paraneoplastic cerebellar degeneration (PCD) is a paraneoplastic syndrome which destroys Purkinje cells of the cerebellum and causes trunk and limb ataxia, dysarthria, diplopia, and vertigo, which often precede the diagnosis of cancer. Anti-Yo PCD is a devastating syndrome that significantly worsens prognosis in terms of functional ability and survival.

METHODS

We present the case of a woman with progressive cerebellar deficits, which were misdiagnosed for several months before breast cancer and anti-Yo antibodies were discovered.

RESULTS

PCD may be misdiagnosed as a primary psychiatric disorder. Results of neuropsychological assessment in this case found subtle attentional dysfunction but relatively preserved cognitive functioning in other domains.

DISCUSSION

The literature relating to PCD and psychiatric manifestations of cerebellar disease are reviewed. The limitations of our current understanding of non-motor cerebellar function are highlighted, asserting the need for further study in this area.

Paraneoplastic neurological syndromes: general treatment overview

OPINION STATEMENT

Major recent discoveries have bringing out a revised definition of paraneoplastic neurological syndromes (PNS), bringing out the concept of antibody-mediated neurological disorders, triggered or not by cancer. Classification of these diseases is not based anymore on the clinical pattern or an underlying tumor, but on the location of the targeted antigens. Indeed, evolution, response to treatment, and pathophysiology are radically different according to the associated antibodies. In some patients with newly described antibodies targeting cell-surface antigens, humoral immunity seems to play a direct role and a dramatic improvement is observed with immunomodulator treatments. In these patients, an associated tumor is less frequent. Conversely, patients with antibodies directed against intracellular targets are, in most cases, characterized by a high degree of irreversible neuronal death mediated by cytotoxic T-cells and do not improve after immunomodulator treatments. In these patients, an associated tumor is highly frequent and must be cured as soon as possible. A third group of patients can be identified with anti-GAD65 and anti-Amphiphysin antibodies. In patients with these antibodies, the efficiency of immunomodulator treatments is less clear as well as the type of immune response that could be a mix between humoral and cellular. In this last group, the antigen is intracellular, but patients may improve with immunomodulator treatments and associated tumors are rare. Thus, identification of associated antibodies should be prompt and the treatment guided according the identified antibody. Mainstream of treatment include the quest of a tumor and its cure. Immunotherapy must be promptly initiated, targeting humoral, or cellular immune response, or both, according to the associated antibodies. Furthermore, in some situations such as Lambert-Eaton Myasthenic Syndromes and Stiff-Person Syndromes, symptomatic drugs can be useful to control the symptoms.

Treatment of paraneoplastic cerebellar degeneration

Paraneoplastic cerebellar degeneration is an uncommon autoimmune disorder characterized clinically by progressive, ultimately incapacitating ataxia and pathologically by destruction of cerebellar Purkinje cells, with variable loss of other cell populations. The disorder is most commonly associated with gynecological and breast carcinomas, small cell carcinoma of the lung, and Hodgkin’s disease and in most cases comes on prior to identification of the underlying neoplasm. The hallmark of paraneoplastic cerebellar degeneration is the presence of an immune response reactive with intracellular proteins of Purkinje or other neurons or, less commonly, against neuronal surface antigens. Evidence-based treatment strategies for paraneoplastic cerebellar degeneration do not exist; and approaches to therapy are thus speculative. Diagnosis and treatment of the underlying neoplasm is critical, and characterization of the antibody response involved may assist in tumor diagnosis. Most investigators have initiated treatment with corticosteroids, plasma exchange, or intravenous immunoglobulin G. Cyclophosphamide, tacrolimus, rituximab, or possibly mycophenolate mofetil may warrant consideration in patients who fail to stabilize or improve on less aggressive therapies. Plasma exchange has been of questionable benefit when used alone but should be considered at initiation of treatment to achieve rapid lowering of circulating paraneoplastic autoantibodies. Because the course of illness is one of relentless neuronal destruction, time is of the essence in initiating treatment. Likelihood of clinical improvement in patients with longstanding symptoms and extensive neuronal loss is poor.

Treatment options in paraneoplastic disorders of the peripheral nervous system

OPINION STATEMENT

Paraneoplastic disorders of the peripheral nervous system (PNS) are the most frequent manifestation of paraneoplasia. As with the central nervous system, two categories of immune mechanisms are distinguished. On one side, antibodies toward intracellular antigens (HuD and CV2-CRMP5) occur with subacute sensory neuronopathy or sensorimotor neuropathy probably depending on a T cell mediated disorder (group 1). On the other side, the Lambert-Eaton myasthenic syndrome (LEMS) and peripheral nerve hyperexcitability (PNH) occur with antibodies to cell membrane antigens, respectively, the voltage gated calcium channel and CASPR2 proteins, which are responsible for the disease (group 2). Treatment recommendation mostly depends on class IV studies. Three lines of therapeutics can be proposed, namely tumor, immunomodulatory and symptomatic treatments. Cancer treatment is crucial since an early tumor cure is the best way to stabilize patients in group 1 and improve those in group 2. This implies the use of an efficient strategy for cancer diagnosis. With group 2 symptomatic treatment including 3,4 diaminopyridine for LEMS and carbamazepine for PNH may suffice to obtain good quality remission. Immunomodulatory treatments like IVIg and plasma exchange, which have a well-established efficacy in antibody dependent diseases, may be used as second line treatments. Rituximab, for which there is only little evidence in this context, may be kept in a third line for severe refractory patients. With group 1 patients, who frequently develop an evolving and disabling disorder, bolus of methylprednisolone and or IVIg may be recommended while searching for and treating the tumor. If the tumor is not found and the patient deteriorates, monthly pulses of cyclophosphamide may stabilize the patients. Antidepressants and antiepileptic drugs efficacious in the treatment of neuropathic pain are to be used as symptomatic treatment when necessary. The choice is then based on the cost effectiveness and tolerance of these drugs.

Paraneoplastic neuropathy

Recent progress in serological screening of paraneoplastic antibodies and in diagnostic imaging techniques to detect malignancies has enabled a broadening of the concept of paraneoplastic neurological syndromes by integrating nonclassic clinical features. The peripheral nervous system is frequently involved in patients with paraneoplastic syndrome and may be seen alone or in combination with involvement of other areas of the nervous system. Destruction of dorsal root ganglion cells due to lymphocytic infiltration, especially with CD8-positive cytotoxic T cells, has been postulated to mediate the classic syndrome of subacute sensory neuronopathy. However, the motor and autonomic nervous systems are frequently affected. Indeed, patients can develop clinical features compatible with Guillain-Barré syndrome, chronic inflammatory demyelinating polyneuropathy, or brachial plexopathy. Other forms of paraneoplastic neuropathy are vasculitic neuropathy, autoimmune autonomic ganglionopathy, and chronic intestinal pseudo-obstruction. Various onconeural antibodies, including anti-Hu, anti-CV2/CRMP-5, and anti-ganglionic acetylcholine receptor antibodies, are associated with neuropathy. Somatic neuropathy is the most common manifestation in patients with anti-Hu and anti-CV2/CRMP-5 antibodies, while anti-ganglionic acetylcholine receptor antibody is associated with autonomic neuropathies. A whole-body fluorodeoxyglucose positron emission tomography scan may be useful to detect malignancy in patients with unremarkable conventional radiological findings. Recognition and diagnosis of paraneoplastic neuropathy is important, as neuropathic symptoms usually precede the identification of the primary tumor, and treatment at an earlier stage provides better chances of good outcomes.

Cellular immune suppression in paraneoplastic neurologic syndromes targeting intracellular antigens

BACKGROUND Tumor treatment is the mainstay of therapy for paraneoplastic neurologic disorders (PNDs), but it is only effective in some cases and other treatment options are limited. OBJECTIVE To evaluate the short-term use of a combination of prednisone and tacrolimus for acute neurologic worsening in PND in which intracellular antigens are targeted. DESIGN Retrospective single-center case series of patients with PND treated with tacrolimus. SETTING The Rockefeller University Hospital, a research hospital in New York, New York. PATIENTS Twenty-six patients with PND with high titer (≥1:1000) anti-HuD, anti-Yo, or anti-CRMP5 autoantibodies were enrolled. Patients were referred from Memorial Sloan Kettering Cancer Center or self-referred. Two patients discontinued intervention owing to adverse events. INTERVENTIONS Patients were treated with tacrolimus, 0.15-0.30 mg/kg per day, in 2 divided oral doses with 60 mg per day of oral prednisone, tapered off during 1 to 4 weeks. MAIN OUTCOME MEASURES The primary outcome measure was median survival. Neurologic examinations before and after treatment as well as adverse events are described. RESULTS Median survival time was 52 months from time of diagnosis. Some patients experienced neurologic improvement that was functionally meaningful. The incidence of adverse events was similar to that generally reported with tacrolimus. CONCLUSIONS A short course of prednisone and tacrolimus to target central nervous system T cells in patients with PND with acute neurologic decline in which intracellular antigens are targeted was well tolerated and warrants further study. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT00378326.

The diagnosis and treatment of limbic encephalitis

The term limbic encephalitis (LE) was first introduced in 1968. While this disease was initially considered rare and is often fatal with very few treatment options, several reports published in the last decade provide a better description of this condition as well as possible causes and some cases of successful treatment. The clinical manifestation of LE is primarily defined by the subacute onset of short-term memory loss, seizures, confusion and psychiatric symptoms suggesting the involvement of the limbic system. In addition, EEG often shows focal or generalized slow wave or epileptiform activity, and MRI findings reveal hyperintense signals of the medial temporal lobes in T2-weighted or FLAIR images. The current literature suggests that LE is not a single disorder but is comprised of a group of autoimmune disorders predominantly affecting the limbic system. Before the diagnosis of LE can be determined, other causes of subacute encephalopathy must be excluded, especially those resulting from infectious aetiologies. LE has previously been regarded as a paraneoplastic phenomenon associated with the classical onconeuronal antibodies that are primarily directed against intracellular antigens. However, recent literature suggests that LE is also associated with antibodies that are directed against cell surface antigens, and these cases of LE display a much weaker association to the neoplasm. The treatment options for LE largely depend on the aetiology of the disease and involve the removal of the primary neoplasm. Therefore, a search for the underlying tumour is mandatory. In addition, immunotherapy has been successful in a significant number of patients where LE is not associated with cancer.

[Autoimmune encephalitis, clinical, radiological and immunological data]

INTRODUCTION

Encephalitis is an inflammatory or infectious disease with an acute or subacute presentation. Immunological abnormalities in serum can be found but may be underdiagnosed. In several cases, a paraneoplastic origin with anti-neuron antibodies is noted. In all cases, other auto-antibodies can be found with or without any neoplastic mechanism.

OBJECTIVES

The aim of our study was to describe a clinical, radiological and immunological cohort of patients with autoimmune encephalitis and suggest a diagnostic and therapeutic algorithm.

PATIENTS AND METHOD

We performed a retrospective study in an immunological unit of neurology. All patients with autoimmune encephalitis between March 2000 and October 2009 were included. The clinical, imaging and immunological evaluations were recorded for each patient.

RESULTS

Our cohort included 16 patients (eight men and eight women), mean age 45.3±10years. All patients had acute or subacute neuropsychological or neuropsychiatric impairment and all patients but one had temporal lobe dysfunction confirmed by cerebral MRI, PET or SPECT. Epilepsy was observed in 56% of cases, extra-temporal lobe impairment in 50%, including sleep disturbances. A cancer was found in only 25% (two small-cell lung cancers, one testis seminoma, one non-small-cell lung cancer with Merckel cells cancer). Anti-neuron antibodies were noted in 56% of cases (two with anti-voltage gate potassium channel complex antibodies (ab), two with anti-NMDA-R ab, two with anti-glutamate acid decarboxylase ab, one with anti-Ma2, two with anti-Hu ab and two remained uncharacterized). Systemic antibodies were found in 50% (one anti-gangliosides, one anti-SSA and one anti-DNA and four antinuclear ab uncharacterized, two anti-TPO and two anti-phospholipids). All patients received immunomodulatory treatments, including intravenous immunoglobulins (IgIV) and cancer was treated. Five patients achieved complete recovery, partial improvement was observed in 10 patients and two patients died.

DISCUSSION

Despite clinical homogeneity at presentation, clinical outcome seems to be different between patients with antibodies against neuronal surface antigens and those with antibodies against intracellular antigens, which are more likely refractory to immunotherapy and paraneoplastic. The frequency of extra-temporal lobe impairment suggests that the term of limbic encephalitis should be changed to autoimmune encephalitis.

Rituximab as potential therapy for paraneoplastic cerebellar degeneration in pediatric Hodgkin disease

Paraneoplastic cerebellar degeneration (PCD) is a rare neurological syndrome associated with lung cancer, breast adenocarcinoma,ovarian adenocarcinoma, and Hodgkin disease. It is rarely seen in pediatrics. We report a case of a 10-year-old boy with a 2-year prodrome that led to a diagnosis of PCD in association with stage IV Hodgkin disease. He received radiation and chemotherapy for his Hodgkin disease with resolution of his lymphoma. Based on promising data in adults on the efficacy of rituximab over other immuno suppressive agents in paraneoplastic disorders, he was treated with rituximab with marked improvement of the cerebellar syndrome.

Movement disorders in autoimmune diseases

Movement disorders have been known to be associated with a variety of autoimmune diseases, including Sydenham's chorea, pediatric autoimmune neuropsychiatric disorders associated with streptococcus, systemic lupus erythematosus, antiphospholipid syndrome, gluten sensitivity, paraneoplastic and autoimmune encephalopathies. Tremors, dystonia, chorea, ballism, myoclonus, parkinsonism, and ataxia may be the initial and even the only presentation of these autoimmune diseases. Although antibodies directed against various cellular components of the central nervous system have been implicated, the pathogenic mechanisms of these autoimmune movement disorders have not yet been fully elucidated. Clinical recognition of these autoimmune movement disorders is critically important as many improve with immunotherapy or dietary modifications, particularly when diagnosed early. We discuss here the clinical features, pathogenic mechanisms, and treatments of movement disorders associated with autoimmune diseases, based on our own experience and on a systematic review of the literature.

Opsoclonus-myoclonus and anti-Hu positive limbic encephalitis in a patient with neuroblastoma

Opsoclonus-myoclonus syndrome (OMS) is seen in 2-3% of children with neuroblastoma and is believed to be caused by an autoimmune process elicited by the tumor. Although long-term neurologic sequelae are common in children with OMS, limbic encephalitis has not previously been reported. We report a child who developed limbic encephalitis associated with anti-Hu antibodies, 6 years after her initial diagnosis of neuroblastoma and OMS. This case demonstrates that patients with neuroblastoma and OMS are at risk for developing new paraneoplastic symptoms years after their original diagnosis and emphasizes the need for careful long-term follow-up.

A case of follicular lymphoma associated with paraneoplastic cerebellar degeneration

Paraneoplastic neurological disorders (PND) are neurological effects of malignancy that are recognized as immune-mediated disorders caused by aberrant expression of a tumor antigen that is normally expressed in the nervous system. We report a case of cerebellar ataxia which turned out to be paraneoplastic cerebellar degeneration, a subtype of PND that develops cerebellar symptoms, that was caused by follicular lymphoma. After chemotherapy, the patient attained sufficient improvement of cerebellar symptoms along with complete remission of lymphoma. Paraneoplastic cerebellar degeneration should be recognized as a rare complication of lymphoma as it is important to start proper treatment before the neurological symptoms become irreversible.

A novel approach to paraneoplastic intestinal pseudo-obstruction

Paraneoplastic neurologic syndromes (PNS) are uncommon, affecting fewer than 1 in 10,000 patients with cancer. PNS, while rare, can cause significant morbidity and impose enormous socio-economic costs, besides severely affecting quality of life. PNS can involve any part of the nervous system and can present as limbic encephalitis, subacute cerebellar ataxias, opsoclonus-myoclonus, retinopathies, chronic intestinal pseudo-obstruction (CIPO), sensory neuronopathy, Lambert-Eaton myasthenic syndrome, stiff-person syndrome, and encephalomyelitis. The standard of care for CIPO includes the use of promotility and anti-secretory agents and the resection of the non-functioning gut segment; all of which can cause significant compromise in the quality of life. There is significant evidence that paraneoplastic neurologic syndromes are associated with antibodies directed against certain nerve antigens. We successfully treated a patient with CIPO in the setting of small cell lung cancer with a combination of rituximab and cyclophosphamide. The patient, who had failed to respond to prokinetic agents, anti-secretory therapy, and multiple resections, responded to the immunomodulatory therapy, with minimal residuals with PEG tube feeding and sustained ostomy output. The use of rituximab and cyclophosphamide should therefore be considered in patients with CIPO, especially if it can avoid complicated surgical procedures.

New concepts in paraneoplastic neurological syndromes

Paraneoplastic neurological syndromes (PNS) are rare diseases defined so far by the presence of a neurological disorder associated with cancer in the absence of invasion of the nervous system by tumor cells. Discovery of circulating autoantibodies specific for these patients has revolutionized the diagnosis and understanding of these syndromes and demonstrated a role of the immune system in the neurological syndromes. Until recent years, we thought that these autoantibodies were only markers of the disease and had no role in the pathophysiology. The recent description of autoantibodies directed against membrane receptors or channels and playing a direct pathological role has transformed the concept of PNS. Especially, it appears that many patients may have a neurological syndrome and autoantibodies without cancer. This results in a classification based on the nature of the autoantibodies associated with neurological syndrome. In case of autoantibodies targeting intracellular antigens, cancer is almost always associated, the neurological disorders are mainly related to neuronal death, patients are rarely sensitive to immunomodulatory treatments and cellular immunity appears to play a major role. In contrast, patients with autoantibodies targeting membrane antigens (receptors, channels or receptor associated proteins) have rarely cancer, neurological disorders are related to a reversible neuronal dysfunction, patients are mostly sensitive to immunomodulatory treatments and it seems that humoral immunity and autoantibodies play a major role.

Movement disorders in paraneoplastic and autoimmune disease

PURPOSE OF REVIEW

The most relevant advances in immune-mediated movement disorders are described, with emphasis on the clinical--immunological associations, novel antigens, and treatment.

RECENT FINDINGS

Many movement disorders previously considered idiopathic or degenerative are now recognized as immune-mediated. Some disorders are paraneoplastic, such as anti-CRMP5-associated chorea, anti-Ma2 hypokinesis and rigidity, anti-Yo cerebellar ataxia and tremor, and anti-Hu ataxia and pesudoathetosis. Other disorders such as Sydenham's chorea, or chorea related to systemic lupus erythematosus and antiphospholipid syndrome occur in association with multiple antibodies, are not paraneoplastic, and are triggered by molecular mimicry or unknown mechanisms. Recent studies have revealed a new category of disorders that can be paraneoplastic or not, and associate with antibodies against cell-surface or synaptic proteins. They include anti-N-methyl-D-aspartate receptor (anti-NMDAR) encephalitis, which may cause dyskinesias, chorea, ballismus or dystonia (NMDAR antibodies), the spectrum of Stiff-person syndrome/muscle rigidity (glutamic acid decarboxylase, amphiphysin, GABA(A)-receptor-associated protein, or glycine receptor antibodies), neuromyotonia (Caspr2 antibodies), and opsoclonus--myoclonus--ataxia (unknown antigens).

SUMMARY

Neurologists should be aware that many movement disorders are immune-mediated. Recognition of these disorders is important because it may lead to the diagnosis of an occult cancer, and a substantial number of patients, mainly those with antibodies to cell-surface or synaptic proteins, respond to immunotherapy.

Progress in the management of paraneoplastic neurological disorders

Paraneoplastic neurological disorders (PNDs) are a rare and diverse group of neurological conditions that can involve any part of the nervous system. Diagnosis is facilitated by finding well-recognized autoantibodies directed against neural antigens in the sera and the cerebrospinal fluid. Identifying and eliminating the underlying malignancy is the mainstay of treatment. Immunomodulatory treatment is gaining more acceptance especially, where a malignancy could not be identified, oncology treatment is completed, or along with cancer treatment. Literature review shows only a handful of systematic prospective case series. Multicenter, prospective controlled clinical trials are needed for future therapeutic advances.

Paraneoplastic syndromes causing movement disorders

Paraneoplastic neurological disorders are an extensive group of neurological syndromes that occur in patients with cancer and often present before the presence of an underlying tumor is known. Many of these disorders appear to be immune-mediated, with targets throughout the nervous system, including basal ganglia and brainstem, in which case they may result in movement disorders. Recent descriptions of new immune-mediated encephalitides in children and adults have substantially increased the number of patients with paraneoplastic movement disorders. There are several key concepts that assist in the identification of a movement disorder as likely paraneoplastic, including a rapid onset, the presence of cerebrospinal fluid inflammatory changes, and in some patients the identification of specific serum and cerebrospinal fluid antineuronal antibodies. Once identified, prompt diagnosis and treatment of the tumor can result in neurological symptom improvement or stabilization, although some patients may require immunotherapy only. Understanding the natural course of each immune-mediated paraneoplastic movement disorder minimizes unnecessary testing and the use of potentially toxic therapies.

Small cell lung cancer presenting with paraneoplastic limbic encephalitis

We report two cases of the rare neurological paraneoplastic syndrome, limbic encephalitis, as the initial presentation of small cell lung cancer. The first case responded to treatment of the underlying malignancy, while the second required more acute treatment in the intensive care setting. In this case, initial treatment was with immunosuppression to achieve a degree of stability before the underlying malignancy could be treated. Both cases had significant improvement in neurological function. These cases highlight the importance of directed investigation to try and identify an underlying malignancy in patients in whom a diagnosis of limbic encephalitis is made, and the difficulty in managing such patients.

Paraneoplastic syndromes: an approach to diagnosis and treatment

Recent medical advances have improved the understanding, diagnosis, and treatment of paraneoplastic syndromes. These disorders arise from tumor secretion of hormones, peptides, or cytokines or from immune cross-reactivity between malignant and normal tissues. Paraneoplastic syndromes may affect diverse organ systems, most notably the endocrine, neurologic, dermatologic, rheumatologic, and hematologic systems. The most commonly associated malignancies include small cell lung cancer, breast cancer, gynecologic tumors, and hematologic malignancies. In some instances, the timely diagnosis of these conditions may lead to detection of an otherwise clinically occult tumor at an early and highly treatable stage. Because paraneoplastic syndromes often cause considerable morbidity, effective treatment can improve patient quality of life, enhance the delivery of cancer therapy, and prolong survival. Treatments include addressing the underlying malignancy, immunosuppression (for neurologic, dermatologic, and rheumatologic paraneoplastic syndromes), and correction of electrolyte and hormonal derangements (for endocrine paraneoplastic syndromes). This review focuses on the diagnosis and treatment of paraneoplastic syndromes, with emphasis on those most frequently encountered clinically. Initial literature searches for this review were conducted using PubMed and the keyword paraneoplastic in conjunction with keywords such as malignancy, SIADH, and limbic encephalitis, depending on the particular topic. Date limitations typically were not used, but preference was given to recent articles when possible.

Update on paraneoplastic neurologic disorders

When patients with cancer develop neurologic symptoms, common causes include metastasis, infections, coagulopathy, metabolic or nutritional disturbances, and neurotoxicity from treatments. A thorough clinical history, temporal association with cancer therapies, and results of ancillary tests usually reveal one of these mechanisms as the etiology. When no etiology is identified, the diagnosis considered is often that of a paraneoplastic neurologic disorder (PND). With the recognition that PNDs are more frequent than previously thought, the availability of diagnostic tests, and the fact that, for some PNDs, treatment helps, PNDs should no longer be considered diagnostic zebras, and when appropriate should be included in the differential diagnosis early in the evaluation.

Update on paraneoplastic neurologic disorders

Once considered rare, paraneoplastic neurologic disorders (PNDs) are an extensive group of neurologic disorders that occur either exclusively or at increased frequency in patients with cancer. PNDs have been increasingly recognized due in large part to the identification of antineuronal antibodies in the serum and cerebrospinal fluid of patients. Although almost any neoplasm can cause PND, the tumors most commonly involved are small-cell lung cancer, cancers of the breast and ovary, thymoma, neuroblastoma, plasma cell tumors, and ovarian teratoma. Establishing the diagnosis of PND is important because in more than two-thirds of patients the neurologic symptoms develop before the presence of the cancer is known. When PND is suspected and no tumor is found, it is recommended that cancer screening be repeated every 6 months. Early diagnosis and intervention offers the best chance of neurologic stabilization or improvement.