Immunological and clinical response to immunosuppressive treatment in paraneoplastic cerebellar degeneration

Ovarian mass Presenting as Paraneoplastic cerebellar degeneration with peripheral neuropathy and anti-Yo antibody

Paraneoplastic neurological syndromes (PNS) are a group of disorders with diverse neurological manifestations that are observed in patients with various types of cancer. Any portion of the nervous system can be affected by these syndromes, which are brought on by processes other than metastasis, direct tumour spread or chemotherapy side effects. An immune-mediated attack on the cerebellar Purkinje cells and consequent cerebellar symptoms define paraneoplastic cerebellar degeneration(PCD), a subtype of the PNS. Axonal or demyelinating paraneoplastic peripheral neuropathies are both possible. Here, we describe the case of a middle-aged woman who presented with subacute-onset cerebellar symptoms and peripheral neuropathy, was discovered to have a positive anti-Yo antibody, and was later detected to have an ovarian mass. This case illustrates the significance of considering a paraneoplastic aetiology in patients with otherwise unexplained neurological manifestations and initiating an appropriate workup and early treatment for the primary malignancy.

Paraneoplastic cerebellar and brainstem disorders

Paraneoplastic cerebellar and brainstem disorders are a heterogeneous group that requires prompt recognition and treatment to help prevent irreversible neurologic injury. Paraneoplastic cerebellar degeneration is best characterized by Yo antibodies in patients with breast or ovarian cancer. Tr (DNER) antibodies in patients with Hodgkin lymphoma can also present with a pure cerebellar syndrome and is one of the few paraneoplastic syndromes found with hematological malignancy. Opsoclonus-myoclonus-ataxia syndrome presents in both pediatric and adult patients with characteristic clinical findings. Other paraneoplastic brainstem syndromes are associated with Ma2 and Hu antibodies, which can cause widespread neurologic dysfunction. The differential for these disorders is broad and also includes pharmacological side effects, infection or postinfectious processes, and neurodegenerative diseases. Although these immune-mediated disorders have been known for many years, mechanisms of pathogenesis are still unclear, and optimal treatment has not been established.

Paraneoplastic cerebellar degeneration with anti-Yo antibodies and an associated submandibular gland tumor: a case report

Background

As a debilitating syndrome, paraneoplastic cerebellar degeneration (PCD) remains challenging to treat. Further, anti-Yo antibody (directed against human cerebellar degeneration-related protein 2) detection in patients with PCD is associated with unsatisfactory responses to existing therapies. Here, we present the case of a 60-year-old woman who developed PCD with anti-Yo antibodies and a submandibular gland tumor.

Case presentation

A 60-year-old woman presented with a 5-day history of unsteadiness of gait and inadequate coordination of her extremities, along with truncal instability. Although walking without aid was possible, dysmetria of all four limbs, trunk, and gait ataxia was observed. While routine biochemical and hematological examinations were normal, the patient’s blood was positive for anti-Yo antibodies. When the neurological symptoms deteriorated despite administration of intravenous methylprednisolone, fluorodeoxyglucose-positron emission tomography (FDG-PET) and computed tomography (CT) images with contrast enhancement were performed, which showed a tumor in the left submaxillary gland. She underwent total left submandibular gland resection, including the tumor; histological and immunohistochemical results revealed a salivary duct carcinoma. She was administered intravenous methylprednisolone, followed by 10 plasma exchange sessions, intravenous immunoglobulins, and cyclophosphamide therapy. Following treatment, her symptoms were not alleviated, even after the reduction of anti-Yo titers.

Conclusions

Although tumor detection was delayed, early tumor detection, diagnosis, and PCD treatment are essential because any delay can result in the progression of the disorder and irreversible neurological damage. Therefore, we recommend that the possibility of a salivary gland tumor should be considered, and whole-body dual-modality CT, including the head and neck, and FDG-PET should be performed at the earliest for patients with well-characterized paraneoplastic antibodies when conventional imaging fails to identify a tumor.

Update on Paraneoplastic Cerebellar Degeneration

Purpose of review: To provide an update on paraneoplastic cerebellar degeneration (PCD), the involved antibodies and tumors, as well as management strategies. Recent findings: PCD represents the second most common presentation of the recently established class of immune mediated cerebellar ataxias (IMCAs). Although rare in general, PCD is one of the most frequent paraneoplastic presentations and characterized clinically by a rapidly progressive cerebellar syndrome. In recent years, several antibodies have been described in association with the clinical syndrome related to PCD; their clinical significance, however, has yet to be determined. The 2021 updated diagnostic criteria for paraneoplastic neurologic symptoms help to establish the diagnosis of PCD, direct cancer screening, and to evaluate the presence of these newly identified antibodies. Recognition of the clinical syndrome and prompt identification of a specific antibody are essential for early detection of an underlying malignancy and initiation of an appropriate treatment, which represents the best opportunity to modulate the course of the disease. As clinical symptoms can precede tumor diagnosis by years, co-occurrence of specific symptoms and antibodies should prompt continuous surveillance of the patient. Summary: We provide an in-depth overview on PCD, summarize recent findings related to PCD, and highlight the transformed diagnostic approach.

Paraneoplastic Diseases of the Central Nervous System

Paraneoplastic neurological syndromes are nonmetastatic complications of malignancy secondary to immune-mediated neuronal dysfunction or death. Pathogenesis may occur from cell surface binding of antineuronal antibodies leading to dysfunction of the target protein, or from antibodies binding against intracellular antigens which ultimately leads to cell death. There are several classical neurological paraneoplastic phenotypes including subacute cerebellar degeneration, limbic encephalitis, encephalomyelitis, and dorsal sensory neuropathy. The patient’s clinical presentations may be suggestive to the treating clinician as to the specific underlying paraneoplastic antibody. Specific antibodies often correlate with the specific underlying tumor type, and malignancy screening is essential in all patients with paraneoplastic neurological disease. Prompt initiation of immunotherapy is essential in the treatment of patients with paraneoplastic neurological disease, often more effective in cell surface antibodies in comparison to intracellular antibodies, as is removal of the underlying tumor.

General principles and escalation options of immunotherapy in autoantibody-associated disorders of the CNS

Autoimmune diseases associated with antineuronal and antiglial autoantibodies (Abs) is one of the most rapidly expanding research fields in clinical neuroimmunology, with more than 30 autoantibodies described so far. Being associated with a wide range of clinical presentations these syndromes can be diagnostically challenging. Surface or intracellular antigen localizations are crucial for the treatment response and outcome. In the latter Abs are mostly of paraneoplastic cause and tumor management should be performed as soon as possible in order to stop peripheral antigen stimulation. Immunotherapy should be started early in both groups, before irreversible neuronal loss occurs. Despite serious prognosis, aggressive therapeutic approaches can be effective in many cases. In this article we review main pathogenic mechanisms leading to Abs-related syndromes and describe standard as well as emerging strategies of immunotherapy, including tocilizumab and bortezomib. Several special therapeutic approaches will be illustrated by clinical cases recently treated in our department.

Immune-mediated Cerebellar Ataxias: Practical Guidelines and Therapeutic Challenges

Immune-mediated cerebellar ataxias (IMCAs), a clinical entity reported for the first time in the 1980s, include gluten ataxia (GA), paraneoplastic cerebellar degenerations (PCDs), antiglutamate decarboxylase 65 (GAD) antibody-associated cerebellar ataxia, post-infectious cerebellitis, and opsoclonus myoclonus syndrome (OMS). These IMCAs share common features with regard to therapeutic approaches. When certain factors trigger immune processes, elimination of the antigen( s) becomes a priority: e.g., gluten-free diet in GA and surgical excision of the primary tumor in PCDs. Furthermore, various immunotherapeutic modalities (e.g., steroids, immunoglobulins, plasmapheresis, immunosuppressants, rituximab) should be considered alone or in combination to prevent the progression of the IMCAs. There is no evidence of significant differences in terms of response and prognosis among the various types of immunotherapies. Treatment introduced at an early stage, when CAs or cerebellar atrophy is mild, is associated with better prognosis. Preservation of the "cerebellar reserve" is necessary for the improvement of CAs and resilience of the cerebellar networks. In this regard, we emphasize the therapeutic principle of "Time is Cerebellum" in IMCAs.

Treatment of Cerebellar Ataxia in the Context of Systemic Diseases

Purpose of review The purpose of this review is to assess the evidence behind treatment regimens for cerebellar ataxias occurring in the context of systemic disease. We will address systemic conditions which are associated with specific involvement of the cerebellum (rather than widespread nervous system involvement) and those conditions for which some degree of evidence of treatment response exists.

Recent findings We have divided systemic disorders affecting the cerebellum into systemic immunological disorders, endocrine and metabolic disorders and paraneoplastic. Recent studies have increased understanding of the range of cerebellar disorders associated with a systemic immunological condition. The identification of newer pathogenic antibodies has improved diagnosis in conditions which would have previously been labelled as idiopathic. However, their rarity and phenotypic variability makes defining optimal immunomodulatory treatment regimens challenging. There is some evidence for beneficial effects of immunomodulation, particularly in anti-GAD ataxia and Hashimoto’s encephalopathy, although, at this time, specific treatment regimens cannot be defined. Immune-mediated paraneoplastic cerebellar disorders show response to therapy dependent, to some extent, on the underlying pathogenic antibody. Much is still to be understood concerning treatment regimens for the ataxic manifestations of metabolic disorders, notably alcohol-induced cerebellar injury, which are common and which are associated with significant disability.

Summary Despite their rarity, cerebellar ataxias occurring in the context of systemic disease cause significant morbidity and better therapies are required to improve outcomes associated with these conditions.

Paraneoplastic cerebellar degeneration with anti-Yo antibodies - a review

The ataxic syndrome associated with Anti-Yo antibody, or Purkinje cell cytoplasmic antibody type 1 (PCA1), is the most common variant of paraneoplastic cerebellar degeneration (PCD). The typical presentation involves the subacute development of pancerebellar deficits with a clinical plateau within 6 months. The vast majority of cases have been reported in women with pelvic or breast tumors. Magnetic resonance imaging of the brain is often normal in the early stages, with cerebellar atrophy seen later. The underlying mechanism is believed to be an immunological reaction to cerebellar degeneration-related protein 2 (CDR2), a protein usually found in the cerebellum that is ectopically produced by tumor cells. Although both B- and T-cell abnormalities are seen, there is debate about the relative importance of the autoantibodies and cytotoxic T lymphocytes in the neuronal loss. Cerebrospinal fluid abnormalities, primarily elevated protein, lymphocytic pleocytosis, and oligoclonal bands, are common in the early stages. The low prevalence of this condition has not allowed for large-scale randomized controlled trials. Immunotherapies, such as steroids, intravenous immune globulins, and plasma exchange, have been extensively used in managing this condition, with limited success. Although some reports indicate benefit from antitumor therapies like surgery and chemotherapy, this has not been consistently observed. The prognosis for anti-Yo PCD is almost uniformly poor, with most patients left bedridden. Further studies are required to clarify the pathophysiology and provide evidence-based treatment options.

Guidelines for treatment of immune-mediated cerebellar ataxias

Immune-mediated cerebellar ataxias include gluten ataxia, paraneoplastic cerebellar degeneration, GAD antibody associated cerebellar ataxia, and Hashimoto’s encephalopathy. Despite the identification of an increasing number of immune-mediated cerebellar ataxias, there is no proposed standardized therapy. We evaluated the efficacies of immunotherapies in reported cases using a common scale of daily activity. The analysis highlighted the importance of removal of autoimmune triggering factors (e.g., gluten or cancer) and the need for immunotherapy evaluation (e.g., corticosteroids, intravenous immunoglobulin, immunosuppressants) and adaptation according to each subtype.

'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.

[Therapeutic options for autoimmune encephalomyelitis]

Autoantibodies to neuronal tissue are becoming increasingly more important in the evaluation and classification of several neurological diseases, e.g. neuromyelitis optica, paraneoplastic syndromes of the central nervous system (CNS), stiff person syndrome or autoimmune epilepsy. As these disorders are rare, no evidence-based recommendations for therapy are available. Currently, immunomodulating or immunosuppressive drugs are administered in most cases. In paraneoplastic syndromes treatment of the underlying cancer is of considerable importance. This overview summarizes current experiences and recommendations in the treatment of autoimmune neurological disorders.

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.

The role of breast MRI in the investigation of anti-Yo positive paraneoplastic cerebellar degeneration

Paraneoplastic neurological syndromes are a group of rare and heterogeneous disorders complicating cancer through immune-mediated mechanisms. They typically arise before the diagnosis of malignancy, thus constituting its first clinical manifestation. A thorough search for the underlying tumour is necessary, as adequate tumour management is essential for both neurological prognosis and overall survival. The authors present the case of a 43 year-old woman who presented with a subacute cerebellar syndrome associated with the paraneoplastic anti-Yo antibody. Although paraneoplastic aetiology was immediately suspected, the diagnosis of the underlying tumour was not straightforward, as is often the case. This case report highlights the importance of directing tumour search for the most probable anatomic locations, according to patient demographics and risk factors as well as the type of onconeural antibodies present, and also the need to use the most sensitive diagnostic modalities appropriate for each target organ.

Paraneoplastic cerebellar degeneration

One of the most dramatic and devastating examples of a remote effect of cancer is paraneoplastic cerebellar degeneration (PCD). There is convincing evidence that this disorder is caused by autoimmunity directed against cerebellar targets. Typically, the neurological presentation antedates the diagnosis of malignancy, and the cancer, when found, tends to be localized and responsive to treatment. Diagnosis depends on clinical suspicion, serology for paraneoplastic antibodies, and a focused search for cancer. Neuronal autoantibody tests facilitate the diagnosis and help direct the search for malignancy. Unfortunately, even with prompt diagnosis, current treatment strategies meet with limited success. Optimum management includes early diagnosis, treatment of cancer to remission, immunosuppression, symptomatic therapies, and compassionate support.

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 sensitive neuropathy associated with anti-hu antibodies in a neuroendocrine tumor of duodenum: a case report

Paraneoplastic sensitive neuropathy is one of the most common presentations among a group of cancer-related disorders known as Paraneoplastic Neurological Syndromes (PNS). PNS likely have an autoimmune etiology since they have been associated with the presence of antibodies against neuronal antigens expressed by tumor cells (such as anti-Hu, anti-Ri and anti-Yo). The tumors most frequently associated with PSN and onconeural antibodies are lung cancer, lymphomas and gynaecological tumors; however, they have also been described in other tumors. We report, for the first time, a case of neuroendocrine tumor of duodenum and PNS associated with anti-Hu antibodies. Moreover, we analyze and discuss the clinical implications that PNS and anti-Hu could have in patients with tumors.

Progressive ataxic gait disorder

Paraneoplastic cerebellar degeneration (PCD) is a well-described paraneoplastic syndrome. In patients with anti-Yo associated PCD, neurological symptoms precede the diagnosis of the underlying cancer in approximately 60% of cases. Ovarian, breast and other gynaecological malignancies are most frequently found as causative malignancies. Antitumour treatment should be commenced at an early stage of the disease. Identification of the tumour is a diagnostic challenge in many of these patients. In the case reported herein, a secondary tumour with unknown primary was suggested after detection of a pathological lymph node in the right axilla by a positron emission tomography scan. Microscopic examination of the ultrasound-guided resected tissue was a poorly differentiated adenocarcinoma strongly positive for the C-ERB 2 oncoprotein. A micro-invasive mammary carcinoma was unable to be localized, even with the aid of magnetic resonance mammography and axillary clearance. Intravenous gamma-globulin and steroid treatment and rehabilitation failed to influence the neurological symptoms. The present patient also demonstrated diffuse increase on the T2 signal in the cerebellum, which may provide a useful diagnostic clue in the assessment of PCD.

Clinical and immunological diversity of limbic encephalitis: a model for paraneoplastic neurologic disorders

The most important contribution to the understanding and management of paraneoplastic neurologic disorders (PND) is the discovery that many of these diseases are immune mediated. It is believed that cytotoxic T-cell responses and antibodies that target neuronal proteins usually expressed by the underlying tumor cause the neurologic symptoms. The detection of these antibodies has provided diagnostic tests that allow recognition of the disorder as paraneoplastic and direct the search of the tumor to selected organs. This article summarizes the authors' findings of limbic encephalitis and postulates that a similar approach can be used for syndromes involving other areas of the nervous system.

Autoimmunity in paraneoplastic neurological syndromes

In patients with Paraneoplastic Neurological Disorders, the researcher detected several autoantibodies reacting with neuronal antigens and tumors; their characteristics supported the hypothesis that autoimmunity plays a part in these diseases and gave impetus to the study of these neurological disorders. The relationship between detection of anti-neuronal antibodies, clinical syndromes, and certain types of tumors suggested the utility of these antibodies as a new tool for clinical diagnosis, although their function in the pathogenesis of the various syndromes is still unclear. This paper intends to review the characteristics of the anti-neuronal antibodies so far identified, their correlation with clinical syndromes, and the function of antigens. In addition, the paper will offer some insights on the immunological mechanisms of neuronal damage and on treatment options.

Immunotherapy for paraneoplastic neurological disorders

Paraneoplastic disorders may affect any part of the central or peripheral nervous systems. Although relatively uncommon, these disorders are a significant cause of severe neurological disability among cancer patients. Most, if not all, neurological paraneoplastic disorders are believed to be autoimmune diseases in which an antitumour immune response also attacks neurons that express shared neuronal tumour antigens. Affected patients often have one or more circulating antineuronal antibodies, which serve as a diagnostic marker for the paraneoplastic condition, and in some cases are the direct mediators of neuronal injury. The exact immunopathogenesis and relative contributions of humoral or cellular immune effectors for most paraneoplastic syndromes are not well understood. Some patients have a gratifying neurological response to tumour treatment and/or immunotherapy, especially if the diagnosis is made early and treatment is initiated promptly. Unfortunately, many patients are left with severe and permanent neurological deficits despite aggressive treatment. This review summarises the current understanding of the clinical immunology of paraneoplastic disorders, and outlines immunotherapy options and outcomes.

Immunomodulatory treatment trial for paraneoplastic neurological disorders

Paraneoplastic neurological disorders are devastating remote effects of malignancy. Despite compelling evidence of an autoimmune pathogenesis, empiric immunomodulatory treatment of these disorders is often ineffective. However, very few systematic studies have been conducted, and the treatment of patients without active malignancy has not been addressed. We conducted a prospective open-label treatment study of plasma exchange plus conventional cancer chemotherapy (10 patients) or plasma exchange plus continuous oral cyclophosphamide (10 patients). All patients had progressive symptoms and at least moderate disability at enrollment (mean Rankin score, 3.4). Patients who had experienced symptoms for more than 12 months were excluded (mean duration of symptoms at enrollment, 3.6 months). The primary outcome measure was change in quantitative disability measures (Rankin and Barthel scores) after 6 months of treatment; a positive response was defined as stability or improvement in disability. Overall, 50% of patients had a positive response at 6 months (6 patients had improved by at least 1 Rankin grade). Patients with good outcome tended to be those with less disability at time of enrollment. Hematologic toxicity was common among those receiving cyclophosphamide. Aggressive immunosuppression early in the clinical course should be considered in patients who have paraneoplastic neurological disorders, even when there is no evidence of active malignancy.

Current Therapies for Paraneoplastic Neurologic Syndromes

Paraneoplastic neurologic syndromes (PNS) comprise an extensive group of heterogeneous disorders that can affect any part of the central and peripheral nervous system. There is evidence that many of these disorders are mediated by immunologic responses triggered by the presence of a cancer. Several immunologic mechanisms and many antigenic targets have been related to these disorders. Some disorders of the neuromuscular junction or peripheral nervous system are directly mediated by antibodies, and they may have a paraneoplastic origin or develop without a tumor association. For these disorders and a few PNS of the central nervous system, immunotherapy may result in neurologic improvement. However, for most PNS of the peripheral and central nervous system the response to any type of therapy is, in general, disappointing. The main concern of the clinician should be to rule out other diagnostic entities and to uncover the presence of the associated neoplasm that often remains elusive to detection. In general, the best approach to treat PNS is to discover and treat the tumor promptly, and provide supportive care for the neurologic deficits with symptomatic treatment and physical therapy. In a few cases, depending on the syndrome and if the patient is in the early stages of the neurologic disease, treatment with immunosuppression may have some effect on the PNS.

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.

Immunotherapeutic approaches to paraneoplastic neurological disorders

The review presents an overview on the pathogenesis of paraneoplastic neurological disorders (PNDs) and the current therapeutic immunosuppressive or immunomodulatory strategies used in these patients. PNDs are disturbances in the functioning of the nervous system in cancer patients, where the disturbances are not due to a local effect of the tumour or its metastases. Most of these clinically, well-defined syndromes in adults are associated with lung cancer (especially small cell lung cancer), lymphomas and gynaecological tumours. Since autoantibodies directed against proteins expressed in neurons and tumour cells have been found, PNDs are suspected to be autoimmune. In neuromuscular PND, immunosuppressive therapies, plasmapheresis and intravenous immunoglobulins are effective treatments. In contrast, central nervous system PNDs seen in adults are by far the most problematic group to treat. With exception of the stiff-man syndrome, immunosuppression appears to have little effect on these neurological disorders. Tumour therapy stabilises PNDs but does not cause improvement. Plasmapheresis reduces the autoantibody titre in the sera of these patients but, like tumour therapy, does not lead to a clinical improvement. In children with paraneoplastic opsoclonus-myoclonus syndrome, steroids and intravenous immunoglobulins may lead to a complete or partial remission of PNDs.

Remote neurologic manifestations of cancer

Paraneoplastic disorders may affect any part of the central or peripheral nervous systems. Although relatively uncommon, these disorders are a significant cause of neurologic morbidity for cancer patients. At least some paraneoplastic syndromes are believed to be caused by an autoimmune reaction against shared tumor-neural antigens. This article summarizes the clinical features of paraneoplastic disorders, the current evidence for autoimmunity, and guidelines for diagnosis and treatment.

Paraneoplastic cerebellar degeneration as the first manifestation of cancer

Paraneoplastic cerebellar degeneration (PCD) is a type of paraneoplastic syndrome that primarily affects women with gynecological cancers. Patients typically experience pancerebellar symptoms, including gait ataxia, dysarthria, nystagmus, and truncal and appendicular ataxia. We present the case of a 50-year-old woman with PCD and presumed ovarian cancer who initially complained of ataxia and dysarthria. PCD was diagnosed on the basis of her symptoms, diagnostic imaging, and laboratory work. PCD symptoms may precede the diagnosis of malignancy by months or years. Early diagnosis and treatment of these syndromes, including rehabilitation, may result in improvements in quality of life for this population of patients.

Treatment of paraneoplastic neurological syndromes with antineuronal antibodies (Anti-Hu, anti-Yo) with a combination of immunoglobulins, cyclophosphamide, and methylprednisolone

OBJECTIVES

To evaluate the effect of a combination of immunoglobulins (IVIg), cyclophosphamide (CTX), and methylprednisolone (MP) on the clinical course of patients with paraneoplastic neurological syndrome (PNS) and antineuronal antibodies (Abs).

METHODS

Seventeen patients with paraneoplastic encephalomyelitis/sensory neuropathy (PEM/SN) with anti-Hu Abs (n = 10) or cerebellar degeneration (PCD) with anti-Yo Abs (n = 7) received one to nine cycles (mean 3.5) of a combination of IVIg (0.5 g/kg/day from days 1 to 5), CTX (600 mg/m2 at day 1) and MP (1g/day from day 1 to 3). The Rankin scale (RS) was used to evaluate the response. A positive response was considered as either improvement or stabilisation in patients who were still ambulatory (RS< or =3) at the onset of treatment, whereas only improvement, and not stabilisation, was considered a therapeutic benefit in bedridden patients (RS> or =4).

RESULTS

Tolerance was good and no patient experienced grade 3/4 toxicity (World Health Organisation). Sixteen patients were evaluable for response. Of the seven patients with RS> or =4, none improved. Of the nine patients with RS< or =3, none improved but three (two SN and one PCD) stabilised for 4, 35, and 16 months.

CONCLUSIONS

This study suggests that vigorous immunosuppressive treatment is not useful in severely disabled PNS patients with antineuronal Abs. In a minority of patients (mainly with SN) who are not severely disabled at the onset of treatment, a transient stabilisation is possible and deserves further evaluation.

Paraneoplastic Diseases of the Nervous System

Several neurologic paraneoplastic disorders are believed to be caused by an autoimmune reaction against an antigen or antigens coexpressed by tumor cells and neurons. Of the paraneoplastic syndromes, the Lambert-Eaton myasthenic syndrome (LEMS)--in which autoantibodies downregulate voltage-gated calcium channels at the presynaptic nerve terminal--is associated with the strongest evidence of an autoimmune cause. For the other syndromes, including cerebellar degeneration, multifocal encephalomyelitis, sensory neuronopathy, limbic encephalitis, opsoclonus-myoclonus, and retinal degeneration, an autoimmune cause is indicated by the presence of specific anti-neuronal antibodies. These antibodies serve as a useful diagnostic tool, but their actual role in causing neuronal injury and clinical disease remains unclear. A small percentage of patients with paraneoplastic disorders shows major neurologic improvement after successful treatment of the associated tumor. Of patients who require further therapy for the neurologic disorder, those with LEMS have the best outcome. The response to immunosuppression among patients with paraneoplastic central nervous system (CNS) dysfunction is much less favorable. Although exceptions clearly exist, most patients with CNS paraneoplastic disorders do not improve despite tumor treatment and immunosuppressive therapy. It is likely that many patients already have irreversible neuronal injury at the time of diagnosis. The decision to attempt immunosuppressive treatment must be made on an individual basis.

Anti-Yo positive paraneoplastic cerebellar degeneration associated with ovarian carcinoma: case report and review of the literature

Paraneoplastic cerebellar degeneration (PCD) is a rare nonmetastatic neurological complication in cancer patients. Anti-Yo is one of the anti-onconeural antibodies found in PCD patients. It is believed that anti-Yo occurs almost always in women and is most likely associated with gynecologic or breast cancers, although exceptions exist. Here we report a PCD patient with ovarian cancer having high-titer anti-Yo. The acute onset of her PCD symptoms mimicked that of a stroke. Her ovarian cancer tissue contained abundant plasma cells and lymphocytes. After a thorough review of the literature, we propose a schematic hypothesis for the autoimmune pathogenesis of PCD. Despite anecdotal case reports of neurological improvement with different combinations of treatment, including IVIg, there is still no definitely effective treatment for PCD. Further research on the pathogenesis of PCD may lead to more effective therapies.

Neurodegeneration in ataxia-telangiectasia is caused by horror autotoxicus

Ataxia-telangiectasia (A-T) is a pleiotropic, multi-system disorder with manifestations that include immune deficiency, sensitivity to ionizing radiation and neoplasms. Many of these manifestations are understood in principle since the identification in A-T patients of mutations in a gene encoding a protein kinase that plays a key role in signaling and repair of DNA damage. However, the cause of the neurodegeneration that afflicts patients with A-T for at least a decade before they succumb to overwhelming infections or malignancy remains mysterious. Based on our work in a mouse model of A-T and previous evidence of extra-neural autoimmune disorders in A-T, we postulate that the neurodegenerative process in A-T is not due to a function for A-T mutated (ATM) essential for the postnatal brain, but to an autoimmune process (hence 'horror autotoxicus', Paul Ehrlich's term for autoimmune disorder). This hypothetical mechanism may be analogous to that in the so-called 'paraneoplastic' neurodegenerative syndromes in patients with various malignancies. Thus, alterations in the balance between cellular and humoral immunity in A-T probably result in autoantibodies to cerebral epitopes shared with cells of the immune system. This hypothesis has important implications for the understanding and development of effective palliative and even preventative strategies for A-T, and probably for other so far relentlessly progressive neurodegenerative disorders.

Neurologic paraneoplastic syndromes

Several neurologic paraneoplastic disorders are believed to be caused by an autoimmune reaction against antigen(s) co-expressed by tumour cells and neurons. Of the paraneoplastic syndromes, the evidence for an autoimmune etiology is strongest for the Lambert-Eaton myasthenic syndrome, in which autoantibodies downregulate voltage-gated calcium channels at the presynaptic nerve terminal. For other syndromes, including cerebellar degeneration, multifocal encephalomyelitis, sensory neuronopathy, limbic encephalitis, opsoclonus-myoclonus, stiff person syndrome, and retinal degeneration, the autoimmune theory is supported by the presence of specific antineuronal antibodies. These antibodies serve as a useful diagnostic tool, but their actual role in causing neuronal injury and clinical disease remains unclear. Further understanding of immunopathogenesis awaits successful experimental models. Among different syndromes, a varied proportion of patients shows neurologic improvement with immunosuppressive treatments; it is likely that many patients have already suffered irreversible neuronal injury at the time of diagnosis.

Motor neuron disease: a paraneoplastic process associated with anti-hu antibody and small-cell lung carcinoma

Although isolated lower motor neuron disease has been reported as a paraneoplastic complication, it has not been previously described, in association with anti-Hu antibody. We report a 51-year-old man in whom weakness heralded the presence of a small-cell cancer of the lung. His neurological disorder was characterized by an unremitting progression of limb, neck, and chest wall weakness and wasting that commenced and remained predominant in the upper limbs. Electrophysiological studies demonstrated widespread denervation and examination of a muscle biopsy specimen showed evidence of acute and chronic denervation. High titers of anti-Hu antibody were detected in the serum and cerebrospinal fluid. Neither objective measures of strength nor titers of anti-Hu antibody responded to corticosteroids, cyclophosphamide, intravenous immunoglobulins, or plasmapheresis. Death from the complications of motor neuron disease ensued 23 months after the onset of weakness. Autopsy revealed tumor in the lung and on pleural and peritoneal surfaces. There was a loss of anterior horn cells in the spinal cord. Despite the absence of symptomatic cerebellar disease, a decrease in the number of Purkinje cells was also detected.