Antibodies of the anti-Yo and anti-Ri type in the absence of paraneoplastic neurological syndromes: a long-term survey of ovarian cancer patients

Neurological adverse events of immune checkpoint inhibitors and the development of paraneoplastic neurological syndromes

Immune checkpoint inhibitors, a class of oncological treatments that enhance antitumour immunity, can trigger neurological adverse events closely resembling paraneoplastic neurological syndromes. Unlike other neurological adverse events caused by these drugs, post-immune checkpoint inhibitor paraneoplastic neurological syndromes predominantly affect the CNS and are associated with neural antibodies and cancer types commonly found also in spontaneous paraneoplastic neurological syndromes. Furthermore, post-immune checkpoint inhibitor paraneoplastic neurological syndromes have poorer neurological outcomes than other neurological adverse events of immune checkpoint inhibitors. Early diagnosis and initiation of immunosuppressive therapy are likely to be crucial in preventing the accumulation of neurological disability. Importantly, the neural antibodies found in patients with post-immune checkpoint inhibitor paraneoplastic neurological syndromes are sometimes detected before treatment, indicating that these antibodies might help to predict the development of neurological adverse events. Experimental and clinical evidence suggests that post-immune checkpoint inhibitor paraneoplastic neurological syndromes probably share immunological features with spontaneous paraneoplastic syndromes. Hence, the study of post-immune checkpoint inhibitor paraneoplastic neurological syndromes can help in deciphering the immunopathogenesis of paraneoplastic neurological syndromes and in identifying novel therapeutic targets.

Evaluation of potential prevalence of onconeural antibodies in women with breast cancer

OBJECTIVE

Aim: To analyse onconeural antibodies in the blood serum of breast cancer patients without neurological symptoms..

PATIENTS AND METHODS

Materials and Methods: The study included 48 women with breast cancer. Paraneoplastic Neurologic Syndromes 12 Ag (IgG) Euroline by EUROIMMUN test was used to determine onconeural antibodies: anti-Hu, anti-Yo, anti-Ri, anti-CV2, anti-Ma/anti-Ta, anti-amphiphysin, anti-recoverin, anti-SOX1, anti-tytin, anti-zic4, anti-GAD65 and anti-Tr (DNER).

RESULTS

Results: The conducted analysis revealed the presence of onconeural antibodies such as: anti-recoverin, anti-CV2, anti-Zic4, anti-SOX1, anti-MA2/Ta and antititin in blood serum of women with breast cancer.

CONCLUSION

Conclusions: Further analysis may allow the assessment of the possible clinical usefulness of these determinations.

A Breakdown of Immune Tolerance in the Cerebellum

Cerebellar dysfunction can be associated with ataxia, dysarthria, dysmetria, nystagmus and cognitive deficits. While cerebellar dysfunction can be caused by vascular, traumatic, metabolic, genetic, inflammatory, infectious, and neoplastic events, the cerebellum is also a frequent target of autoimmune attacks. The underlying cause for this vulnerability is unclear, but it may be a result of region-specific differences in blood–brain barrier permeability, the high concentration of neurons in the cerebellum and the presence of autoantigens on Purkinje cells. An autoimmune response targeting the cerebellum—or any structure in the CNS—is typically accompanied by an influx of peripheral immune cells to the brain. Under healthy conditions, the brain is protected from the periphery by the blood–brain barrier, blood–CSF barrier, and blood–leptomeningeal barrier. Entry of immune cells to the brain for immune surveillance occurs only at the blood-CSF barrier and is strictly controlled. A breakdown in the barrier permeability allows peripheral immune cells uncontrolled access to the CNS. Often—particularly in infectious diseases—the autoimmune response develops because of molecular mimicry between the trigger and a host protein. In this review, we discuss the immune surveillance of the CNS in health and disease and also discuss specific examples of autoimmunity affecting the cerebellum.

Immune checkpoint inhibitor-induced aseptic meningitis and encephalitis: a case-series and narrative review

BACKGROUND

Along with the increasing use of immune checkpoint inhibitors comes a surge in immune-related toxicity. Here, we review the currently available data regarding neurological immune adverse events, and more specifically aseptic meningitis and encephalitis, and present treatment and diagnostic recommendations. Furthermore, we present five cases of immunotherapy-induced aseptic meningitis and encephalitis treated at our institution.

RECENT FINDINGS

Neurological immune-related adverse events, including aseptic meningitis and encephalitis, secondary to checkpoint inhibitors are a rare but complex and clinically relevant entity, comprising a wide range of diseases, most often presenting with symptoms with a wide range of differential diagnoses. Our case-series highlights the challenges of such entities and the importance of properly identifying and managing aseptic meningitis and encephalitis.

SUMMARY

Checkpoint inhibitor-induced meningoencephalitis warrants prompt investigations and treatment. Properly diagnosing aseptic meningitis, encephalitis, or mixed presentations may guide the treatment decision, as highlighted by our case-series. After rapid exclusion of alternative diagnoses, urgent corticosteroids are the therapeutic backbone but this could change in favour of highly specific cytokine-directed treatment options.

PLAIN LANGUAGE SUMMARY

Aseptic meningitis and encephalitis with immune checkpoint inhibitors: a single centre case-series and review of the literature Over the course of the past decade, checkpoint inhibitors have revolutionized cancer care. With their favourable toxicity profile and potential for durable and deep responses, they have become ubiquitous across the field of oncology. Furthermore, combination checkpoint inhibitors are also gaining ground, with increased efficacy and, unfortunately, immune-related toxicity. While there are guidelines based on extensive clinical experience for frequent adverse events, uncommon entities are less readily identified and treated. Neurological immune-related adverse events secondary to checkpoint inhibitors are a rare but complex entity, comprising a wide range of diseases, most often presenting with aspecific symptoms. In this paper, we discuss a single institution case-series of patients with autoimmune aseptic meningitis and encephalitis, and we perform a narrative literature review on this subject. We conclude with our treatment recommendations based on available evidence.

Immunological Bases of Paraneoplastic Cerebellar Degeneration and Therapeutic Implications

Paraneoplastic cerebellar degeneration (PCD) is a rare immune-mediated disease that develops mostly in the setting of neoplasia and offers a unique prospect to explore the interplay between tumor immunity and autoimmunity. In PCD, the deleterious adaptive immune response targets self-antigens aberrantly expressed by tumor cells, mostly gynecological cancers, and physiologically expressed by the Purkinje neurons of the cerebellum. Highly specific anti-neuronal antibodies in the serum and cerebrospinal fluid represent key diagnostic biomarkers of PCD. Some anti-neuronal antibodies such as anti-Yo autoantibodies (recognizing the CDR2/CDR2L proteins) are only associated with PCD. Other anti-neuronal antibodies, such as anti-Hu, anti-Ri, and anti-Ma2, are detected in patients with PCD or other types of paraneoplastic neurological manifestations. Importantly, these autoantibodies cannot transfer disease and evidence for a pathogenic role of autoreactive T cells is accumulating. However, the precise mechanisms responsible for disruption of self-tolerance to neuronal self-antigens in the cancer setting and the pathways involved in pathogenesis within the cerebellum remain to be fully deciphered. Although the occurrence of PCD is rare, the risk for such severe complication may increase with wider use of cancer immunotherapy, notably immune checkpoint blockade. Here, we review recent literature pertaining to the pathophysiology of PCD and propose an immune scheme underlying this disabling disease. Additionally, based on observations from patients' samples and on the pre-clinical model we recently developed, we discuss potential therapeutic strategies that could blunt this cerebellum-specific autoimmune disease.

Rare case of paraneoplastic cerebellar degeneration secondary to high-grade serous carcinoma of tubo-ovarian origin

This case describes a 69-year-old woman, who presented with rapidly progressive cerebellar symptoms and unintentional weight loss. Full neurological assessment excluded space-occupying lesions, vascular accidents and infection. Surprisingly, a chest, abdomen and pelvis CT showed a left hemipelvis mass, which was subsequently biopsied. A high-grade serous carcinoma of tubo-ovarian origin was found, diagnosing paraneoplastic cerebellar degeneration (PCD) secondary to this. The exact mechanism is not known, but is thought to be immune-mediated. In cases of PCD, after cancer treatment, the neurological disability stabilises to a severe level and will unfortunately be lifelong. Our patient continues to make great progress with intensive rehabilitation for her ongoing balance issues. Early recognition of PCD can lead to a prompt diagnosis of the underlying malignancy and hence subsequent management. This can at least limit the extent of the neurological disability of the disease and increase the survival rate from cancer.

The role of the laboratory in the expanding field of neuroimmunology: Autoantibodies to neural targets

Accelerated identification of autoantibodies associated with previously idiopathic neurological disease has provided insights into disease mechanisms, enhanced understanding of neurological function, and opportunities for improved therapeutic interventions. The role of the laboratory in the expanding field of neuroimmunology is critical as specific autoantibody identification provides guidance to clinicians in diagnosis, prognosis, tumor search strategies, and therapeutic interventions. The number of specific autoantibodies identified continues to increase and newer testing strategies increase efficiencies in the laboratory and availability to clinicians. The need for broadly targeted efficient testing is underscored by the variability in clinical presentation and tumor associations attributable to a specific autoantibody, and conversely the various autoantibody specificities that can be the cause of a given clinical presentation. While many of the antineural antibodies were first recognized in the setting of neoplastic disease, idiopathic autoimmune neurological disease in the absence of underlying tumor is increasingly recognized. Appropriation of therapeutic modalities used to treat autoimmune disease to treat these autoantibody mediated neurological diseases has improved patient outcomes. Interaction between clinicians and laboratorians is critical to our understanding of these diseases and optimization of the clinical benefits of our increasing knowledge in neuroimmunology.

Paraneoplastic antigens as biomarkers for early diagnosis of ovarian cancer

Paraneoplastic syndromes are a group of rare disorders that can be triggered by an abnormal immune response to proteins from tumors of the lung, ovary, lymphatics, or breast. Paraneoplastic clinical syndromes affect < 1% of patients with cancer; however, the frequency of subclinical levels of paraneoplastic autoantibodies in asymptomatic patients with cancer is unknown. Numerous studies have reported that ovarian cancer patients show signs of paraneoplastic neurological syndromes (PNSs) before or after their cancers are diagnosed. PNSs arise from a tumor-elicited immune response against onconeural antigens that are shared by tissues of nervous system, muscle, and tumor cells. Studies on the serum IgGs obtained from ovarian cancer patients have indicated the presence of onconeural antibodies in the absence of any PNS symptoms. The occurrence of PNSs is low in ovarian cancer patients and it can be accompanied by onconeural antibodies. The diagnosis of PNSs is accompanied by a suspicion of a malignant tumor such that neurologists typically refer such patients for a tumor diagnostic workup. There will be tremendous utility if subclinical levels (without paraneoplastic neurological symptoms or myositis) of these autoantibodies to paraneoplastic antigens can be exploited to screen asymptomatic high-risk patients for ovarian cancer, and used as biomarkers in immunoassays for the early detection or recurrence of ovarian cancer. Ovarian cancer overall survival is likely to be improved with early detection. Therefore, a panel of onconeural antigens that can detect paraneoplastic autoantibodies in patient sera should provide diagnostic utility for an earlier therapeutic intervention. Here we review the usefulness of PNS and other paraneoplastic syndromes and their association with paraneoplastic antigens to exploit these autoantibody biomarkers to form diagnostic multi-analyte panels for early detection of ovarian cancer.

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.

'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.

Is there a paraneoplastic ALS?

Our objective was to examine the strength of evidence in support of the paraneoplastic syndrome (PNS) as one cause of ALS and, if the association appears more likely than chance, determine which features of ALS imply concurrent malignancy. We reviewed the literature on concurrent ALS and neoplasia assessing the strength of evidence for the association. Most accounts of ALS and neoplasm are case reports or small uncontrolled series. In order of strength of evidence, three clinical situations that support a paraneoplastic aetiology for ALS are: 1) laboratory evidence of well-characterized onconeuronal antibodies, most often anti-Hu, anti-Yo or anti-Ri; 2) co-occurrence of ALS and a neoplasm known to cause PNS, usually lymphoma or cancer of the breast; and 3) combined ALS and a neoplasm not classically associated with PNS, without detectable onconeuronal antibodies. Clinical features that warrant evaluation of neoplasm include upper motor neuron disease in elderly females, rapid progression, non-motor signs, and young onset. In conclusion, most examples of ALS and neoplasm do not constitute a classically established PNS. Rare instances of elevated onconeuronal antibody titres or typical neoplasm, implies that, albeit rare, the PNS is one of a multitude of causes of ALS.

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.

Paraneoplastic neurological syndromes associated with ovarian tumors

Introduction

Paraneoplastic neurological syndromes (PNS) are neurologic deficits triggered by an underlying remote tumor. PNS can antedate clinical manifestation of ovarian malignancy and enable its diagnosis at an early stage. Interestingly, neoplasms associated with PNS are less advanced and metastasize less commonly than those without PNS. This suggests that PNS may be associated with a naturally occurring antitumor response.

Methods

We review the literature on the diagnosis, pathogenesis and management of PNS associated with ovarian tumors: paraneoplastic cerebellar degeneration (PCD) and anti-N-methyl-d-aspartate receptor (anti-NMDAR) encephalitis. An approach to the diagnostic workup of underlying tumors is discussed.

Results

PCD can precede the manifestation of ovarian carcinoma. Anti-NMDAR encephalitis in young women appears often as a result of ovarian teratoma. Since ovarian tumors and nervous tissue share common antigens (e.g., cdr2, NMDAR), autoimmune etiology is a probable mechanism of these neurologic disorders. The concept of cross-presentation, however, seems insufficient to explain entirely the emergence of PNS. Early resection of ovarian tumors is a significant part of PNS management and improves the outcome.

Conclusions

The diagnosis of PNS potentially associated with ovarian tumor indicates a need for a thorough diagnostic procedure in search of the neoplasm. In some patients, explorative laparoscopy/laparotomy can be considered.

Cell-mediated immune responses in paraneoplastic neurological syndromes

Paraneoplastic neurological syndromes (PNS) are disorders of the nervous system that are associated with remote effects of malignancy. PNS are considered to have an autoimmune pathology. It has been suggested that immune antitumor responses are the origin of improved outcome in PNS. We describe cell-mediated immune responses in PNS and their potential contributions to antitumor reactions. Experimental and neuropathological studies have revealed infiltrates in nervous tissue and disturbances in lymphocyte populations in both cerebrospinal fluid and peripheral blood. A predominance of cytotoxic T lymphocytes (CTLs) over T helper cells has been observed. CTLs can be specifically aggressive against antigens shared by tumors and nervous tissue. Based on genetic studies, a common clonal origin of lymphocytes from blood, tumor, and nervous tissue is suggested. Suppressive regulatory T (Treg) lymphocytes are dysfunctional. Simultaneously, in tumor tissue, more intense cell-mediated immune responses are observed, which often coincide with a less aggressive course of neoplastic disease. An increased titer of onconeural antibodies is also related to better prognoses in patients without PNS. The evaluation of onconeural and neuronal surface antibodies was recommended in current guidelines. The link between PNS emergence and antitumor responses may result from more active CTLs and less functional Treg lymphocytes.

Autoimmune encephalitis: A potentially reversible cause of status epilepticus, epilepsy, and cognitive decline

Objectives:

To review clinical characteristics and response to immunomodulation therapy in autoimmune encephalitis presenting with status epilepticus (SE), epilepsy, and cognitive decline.

Design:

Observational, prospective case series.

Setting:

All India Institute of Medical Sciences, New Delhi, India.

Materials and Methods:

Prospective analysis of 15 patients, who presented with SE, epilepsy, cognitive decline, and other neurological symptoms with positive autoantibodies. Demographic and clinical characteristics were recorded. Brain magnetic resonance imaging (MRI), cerebrospinal-fluid analysis (CSF), and tumor screening were done periodically. Treatment received and responses (categorized as per patients and treating doctor's information) were noted.

Results:

There were 15 (males = 10) patients of autoimmune encephalitis. The mean age of presentation was 24 years (range: 2-64 years). The most common onset was subacute (64%) and four (29%) patients presented as SE. Predominant clinical presentations were seizures (100%) almost of every semiology. CSF was done in 10 patients; it was normal in 60%. Brain MRI was done in all patients, in six (40%) it was normal, six (40%) showed T2W and FLAIR hyperintensities in bilateral limbic areas. Antibodies found were the N-methyl-D-aspartate receptor antibody in seven (50%), voltage-gated potassium channel antibody in five (36%), two of antiglutamic acid decarboxylase, and one patient with double stranded DNA (dsDNA) antibodies. None showed evidence of malignancy. Patients received immunotherapy, either steroids, intravenous immunoglobulin, or both. Follow-up showed significant improvement in majority of cases, neither further seizures nor relapse in nine (67%) cases. One death occurred, due to delayed presentation.

Conclusions:

Uncommon but potentially reversible causes of SE, epilepsy, and cognitive decline may be immune-related and high index of suspicion will prevent missing the diagnosis.

Neuronal autoantigens--pathogenesis, associated disorders and antibody testing

The discovery of disorders that are associated with antibodies to neuronal cell-surface proteins has led to a paradigm shift in our understanding of CNS autoimmunity. These disorders can occur in patients with or without cancer-often children or young adults who develop psychosis, catatonic or autistic features, memory problems, abnormal movements, or seizures that were previously considered idiopathic. The autoantigens in such cases have crucial roles in synaptic transmission, plasticity and peripheral nerve excitability. Patients can be comatose or encephalopathic for months and yet fully recover with supportive care and immunotherapy. By contrast, disorders in which the antibodies target intracellular antigens, and in which T-cell-mediated irreversible neuronal degeneration occurs, show a considerably poorer response to treatment. In this article, we review the various targets of neuronal antibodies, focusing predominantly on autoantigens located on the cell surface or synapses-namely, N-methyl-D-aspartate receptors, α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors, γ-aminobutyric acid receptors, leucine-rich glioma-inactivated protein 1, contactin-associated protein-like 2, and metabotropic glutamate receptors. We also provide an algorithm to identify and assess antibodies that bind to cell-surface and synaptic antigens.

Autoantibodies against the Ca(2+)-binding protein recoverin in blood sera of patients with various oncological diseases

In cancer, the retinal Ca(2+)-binding protein recoverin is a paraneoplastic antigen, the aberrant expression of which is capable of triggering the appearance of specific autoantibodies in the serum of patients with malignant tumors and the subsequent development of a paraneoplastic syndrome, cancer-associated retinopathy (CAR). The frequency of serum autoantibodies against recoverin (AAR), earlier determined at a rate of 15-20% in lung cancer, is much higher than the frequency of CAR syndrome, which is approximately 1%. In the present study, we estimated for the first time the frequencies of serum AAR in patients with various types of malignancies other than lung cancer. Patient biospecimens were collected to analyze for the presence of AAR. Additionally, various cell lines were cultivated and analyses were performed using Western blotting and RT-PCR. Results showed that in all cases tested, the AAR frequencies did not exceed 10%. Five AAR-positive patients with various types of cancer were available for ophthalmological investigation and only one of these patients had CAR syndrome. This result is consistent with the conclusion made in our previous studies of lung cancer that serum AAR do not necessarily trigger the development of CAR syndrome.

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.

Onconeural antibodies in sera from patients with various types of tumours

PURPOSE

We assessed the frequency and levels of onconeural antibodies in 974 patients with various types of tumours, but without apparent paraneoplastic neurological syndromes (PNS).

PATIENTS AND METHODS

We included patients with the following tumours: 200 small-cell lung cancer (SCLC) patients, 253 breast cancer patients, 182 ovarian cancer patients, 266 uterine cancer patients and 73 thymoma patients, as well as 52 patients with PNS and cancer and 300 healthy blood donors. Sera were screened for amphiphysin, CRMP5, Hu, Ma2, Ri and Yo antibodies using a multi-well immunoprecipitation technique.

RESULTS

The most frequently detected antibodies were Hu followed by CRMP5. Ma2, Yo, amphiphysin and Ri antibodies were less common, but each was found at similar frequencies. Onconeural antibodies were present at similar levels in sera from the PNS control group and from cancer patients. Hu antibodies were rare in cancers other than SCLC. CRMP5 was the only antibody found in patients with thymoma and this antibody was more common among patients with thymoma than in other tumour patients. With one exception, coexisting antibodies were only found in patients with SCLC. The presence of onconeural antibodies in SCLC patients was not associated with prolonged survival.

CONCLUSION

Onconeural antibodies are associated with various types of tumours suggesting that all antibodies should be included in the serological screening for possible PNS. The levels of onconeural antibody are not sufficiently sensitive to discriminate between cancer patients with PNS and those without.

Paraneoplastic movement disorders

Neurologic paraneoplastic syndromes (NPSs) result from damage to the nervous system due to the remote effects of cancer not related to metastasis, infection, or metabolic derangements. NPSs are rare, affecting 1 in 10,000 patients with cancer. Pathogenesis is likely related to the immune mechanisms: normal neural tissue is mistakenly attacked due to the similarity in the onconeural antigens expressed by the tumor cells. Among the various "classic" and other NPSs, this review focuses on paraneoplastic movement disorders, including ataxia due to cerebellar degeneration, stiff-person syndrome, opsoclonus-myoclonus syndrome, chorea, parkinsonism, and tremor. The recently described syndrome of paraneoplastic anti-N-methyl-D-aspartate receptor encephalitis is also included, given that these patients have complex movements such as stereotypies and dyskinesias in addition to psychiatric symptoms, altered sensorium, and other neurologic signs. Although variable, treatment and prognosis of NPSs rely heavily on treatment of the underlying malignancy and immunotherapy.

Paraneoplastic neurological syndromes: a review

BACKGROUND

Paraneoplastic neurologic syndromes (PNS) constitute a rare group of disorders resulting from damage to the nervous system in the setting of cancer physically unrelated to the tumor site. PNS are believed to result from an autoimmune attack of normal neuronal tissue, spurred by similar neuronal antigens ectopically expressed by tumor cells.

REVIEW SUMMARY

The most common PNS are reviewed and also their association with specific onconeural antibodies, some directly pathogenic, others whose role in the disease process is less clear-cut. This diversity in pathogenesis is likely due to the relative role of humoral versus cellular immunity in PNS. Virtually any cancer may result in PNS but certain tumors, small cell lung cancer, gynecologic cancers (breast and ovarian), thymoma, and plasma cell tumors are more frequently encountered. In most instances, immunosuppressive therapy is unhelpful and outcome is poor.

CONCLUSIONS

PNS have diverse presentations, affecting both the central and peripheral nervous system and commonly, it is the PNS, not cancer that is the presenting symptom. Only subsequently, after onconeural antibodies are discovered or cancer is found, is PNS diagnosed. Neurologists should familiarize themselves with these rare syndromes and treatment principles, as rapid detection and treatment of the underlying tumor offer the best chance for recovery or prevention of further neurologic deterioration.

CRMP5 antibodies in patients with small-cell lung cancer or thymoma

The collapsin response mediator protein 5 (CRMP5) antibody is usually associated with paraneoplastic neurological syndrome (PNS) and small-cell lung cancer (SCLC) or thymoma. The objective of this study was to assess the frequency of CRMP5 antibodies in patients with such tumours and to see if the presence of antibodies was associated with prognosis in these cancers. A multi-well adapted immunoprecipitation assay using radiolabelled recombinant CRMP5 protein, produced by coupled in vitro transcription/translation, was used for the detection of CRMP5 antibodies. Sera from 200 patients with SCLC, 73 patients with thymoma and myasthenia gravis (MG) and from 300 healthy blood donors were examined for CRMP5 antibodies. Positive sera were also examined by immunofluorescence and immune blots. The serological results were compared with disease severity of the patients with thymoma or SCLC. CRMP5 antibodies were detected in 10/200 (5%) of the SCLC, 9/73 (12%) of the thymomas and in 2/300 (0.6%) of the healthy controls by immunoprecipitation. The antibodies were less frequently detected by immunofluorescence or immune blots. There was no significant correlation between CRMP5 antibodies and disease severity. CRMP5 antibodies are more than twice as frequent, and the antibody levels are higher in patients with thymoma and MG than in patients with SCLC. The antibodies are correlated to these tumours, but not to disease severity.

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.

Asymptomatic persistence of anti-Yo antibodies for 5 years without relapse of malignancy

Neurological paraneoplastic syndromes (NPS) are rare disorders in association with malignancy and the presence of various antineuronal antibodies. The persistence of antineuronal antibodies for years after the eradication of the tumor without clinical manifestations of a NPS has not been reported. In a 64-year-old woman with a history of gynecologic malignancy, treated by surgery and chemotherapy with docetaxel and carboplatin, ptosis, hypertelorism, dysarthria, short stature, upper and lower limb weakness, exaggerated tendon reflexes and recurrent creatine-kinase elevation were found. Nerve conduction studies disclosed polyneuropathy and muscle biopsy nonspecific myopathic features. Though anti-Yo antibodies were repeatedly positive, the clinical findings and polyneuropathy were rather attributed to a suspected metabolic myopathy or chemotherapy than a NPS. Anti-Yo antibodies remained positive at 5 further determinations. During the 5 years of follow up there was improvement of polyneuropathy and no relapse of the malignancy, as assessed clinically, by tumor markers, computed tomography scans and 18-fluorodeoxyglucose positron emission tomography. Anti-Yo antibodies may occur without the typical clinical manifestations of a NPS and may persist for years without the development of a NPS or relapse of the tumor.

Paraneoplastic neurological syndromes and onconeural antibodies: clinical and immunological aspects

Paraneoplastic neurological syndromes (PNS) are infrequent disorders that are associated with cancer. The syndromes are highly heterogeneous and often affect several areas of the nervous system. Among the most well-known syndromes are paraneoplastic encephalomyelitis, cerebellar degeneration, sensory neuronopathy, and Lambert-Eaton myastenic syndrome. There are various associated tumors, in particular small cell lung cancer, cancer of the breast and ovary, and thymoma. The onset of neurological symptoms often precedes the cancer diagnosis, and the recognition of a paraneoplastic syndrome should lead to immediate search for cancer. The etiology of the paraneoplastic syndromes is believed to be autoimmune. Antibodies to onconeural antigens, expressed in the tumor of the affected individual and in normal neurons, are found in many of the patients. These antibodies are useful markers for paraneoplastic etiology. The pathogenesis of the PNS is uncertain, but cellular immune responses are thought to be the main effector mechanism. The cornerstone of therapy is the identification and treatment of the underlying malignancy. In some of the disorders, immunosuppressive therapy is of additional benefit. The prognosis of the different PNS varies depending on the level of affection and the degree of neuronal death.

A rare gynecological case of paraneoplastic cerebellar degeneration discovered by FDG-PET

BACKGROUND

PET/CT may be particularly useful to detect the primary cancer in paraneoplastic cerebellar degeneration (PCD) with anti-Yo which is most commonly associated with breast, ovarian and other gynecological cancers.

CASE

A 60-year-old woman developed a PCD associated with anti-Yo antibodies in serum and cerebrospinal fluid. Conventional imaging was negative. FDG-PET showed an abnormal hot spot in the right ovarian area associated with lombo aortic lymph nodes. The diagnosis was confirmed by surgery as an ovarian adenocarcinoma.

CONCLUSION

In this case report, FDG-PET played a crucial role in detecting the unknown primary tumor in a patient with PCD.

Ataxias

Gait disorders in elderly individuals are a major cause of falls and their attendant morbidities. Ataxia is one of the neurologic components of fall risk, as are inattention or confusion, visual impairment, vestibular impairment, subcortical white matter disease, parkinsonism, weakness, sensory loss, orthostasis or arrhythmia with alterations in blood pressure, pain, medication use, and environmental hazards. Ataxia in the geriatric population has many causes. Correctly identifying them can improve clinicians' ability to offer treatment and management strategies to patients and their families. The goals should be safe mobility and preserved activities of daily living.

Ri antibodies in patients with breast, ovarian or small cell lung cancer determined by a sensitive immunoprecipitation technique

The presence of circulating antineuronal antibodies has been associated with paraneoplastic neurological syndromes (PNS). Ri antibodies are often associated with lung or breast cancer, but the prevalence of such antibodies in large cancer materials is largely unknown. We used a highly sensitive immunoprecipitation assay to study the level of Ri antibodies in blood samples from 200 patients with small cell lung cancer (SCLC), 253 patients with breast cancer and 557 patients with ovarian cancer. Two hundred blood donors and six Ri positive PNS patients served as controls. The recombinant antigen used in the immunoprecipitation assay was radiolabeled by a coupled in vitro transcription and translation (ITT) technique, enabling low levels of antibodies to be detected. None of the blood donors contained Ri antibodies, whereas all of the sera from the PNS patients were positive. Ri antibodies were present in 4.5% of the patients with SCLC, 0.8% of the patients with breast cancer and in 0.2% of the patients with ovarian cancer. Retesting of the Ri positive samples with immunofluorescense and immune blot showed that the immunoprecipitation technique was more sensitive than the other immune assays. Ri antibodies were not associated with PNS in the patients with breast or ovarian cancer. Neurological data were not available for the SCLC patients, but in these, Ri antibodies were not associated with survival.

Paraneoplastic syndromes affecting the nervous system

The paraneoplastic neurologic disorders (PND) are a diverse group of diseases characterized by the presence of neurologic dysfunction in the setting of a remote cancer. PND can affect almost any part of the nervous system, and are most commonly associated with lung cancer (small cell) and gynecologic tumors. Laboratory studies have demonstrated that an autoimmune response links the neurologic disorder and the cancer, and established a model whereby the cancer is believed to initiate the syndrome by expressing a protein antigen normally expressed in the nervous system, leading to anti-tumor immune response followed by autoimmune neurologic symptoms. We review the currently known PND and their pathogenesis.

Yo antibodies in ovarian and breast cancer patients detected by a sensitive immunoprecipitation technique

Onconeural antibodies are found in patients with cancer and are associated with paraneoplastic neurological syndromes (PNS). The objective of the present study was to assess the frequency of Yo antibodies in ovarian and breast cancer using a sensitive immunoprecipitation technique, and to look for any association of Yo antibodies with neurological symptoms and prognostic factors. A multiwell adapted fluid-phase immunoassay using radiolabelled recombinant cerebellar degeneration related protein (cdr2), produced by coupled in vitro transcription/translation was used for the detection of Yo antibodies. This technique combines high specificity and sensitivity with high sample analysing capacity for the antibody in question. Sera or EDTA-blood from 810 ovarian (n = 557) and breast cancer (n = 253) patients were analysed for Yo antibodies by immunoprecipitation, as well as immunofluorescence and immune blots. Two hundred healthy blood donors and sera from 17 patients with paraneoplastic cerebellar degeneration and Yo antibodies served as controls. Immunoprecipitation was more sensitive in detecting Yo antibodies than immunofluorescence and immune blots. The prevalence of Yo antibodies was 13/557 (2.3%) in ovarian cancer and 4/253 (1.6%) in breast cancer using immunoprecipitation. Yo antibodies were not correlated with specific histological subgroups. The Yo index of ovarian cancer patients in FIGO stage IV was higher compared to FIGO stage I-III. The prevalence of Yo antibodies was 3 times higher in patients with stage III breast cancer than in stage I and II. Only 2/17 (11.8%) patients with Yo antibodies detected during the screen of 810 cancer patients had PNS. The results show that the prevalence of Yo antibodies is low in ovarian and breast cancer. Yo antibodies may be associated with advanced cancer, but less often with PNS.

Neuroimmunology of the paraneoplastic neurological degenerations

The paraneoplastic neurological degenerations (PNDs) are remarkable examples of naturally occurring tumor immunity in humans. In PND patients, common tumors such as breast, ovarian and lung tumors express proteins normally made exclusively in the brain, eliciting an immune response that successfully suppresses growth of the tumor. This successful anti-tumor response would be expected to go clinically unnoticed by the patient, but the immune cells mediating the response somehow cross into the brain, resulting in an autoimmune attack on neurons and neurological symptoms. Pieces of the mystery of this tumor immune response and neuronal autoimmunity have been assembled, but much more needs to be learned.

Recommended diagnostic criteria for paraneoplastic neurological syndromes

BACKGROUND

Paraneoplastic neurological syndromes (PNS) are defined by the presence of cancer and exclusion of other known causes of the neurological symptoms, but this criterion does not separate "true" PNS from neurological syndromes that are coincidental with a cancer.

OBJECTIVE

To provide more rigorous diagnostic criteria for PNS.

METHODS

An international panel of neurologists interested in PNS identified those defined as "classical" in previous studies. The panel reviewed the existing diagnostic criteria and recommended new criteria for those in whom no clinical consensus was reached in the past. The panel reviewed all reported onconeural antibodies and established the conditions to identify those that would be labelled as "well characterised". The antibody information was obtained from published work and from unpublished data from the different laboratories involved in the study.

RESULTS

The panel suggest two levels of evidence to define a neurological syndrome as paraneoplastic: "definite" and "possible". Each level can be reached combining a set of criteria based on the presence or absence of cancer and the definitions of "classical" syndrome and "well characterised" onconeural antibody.

CONCLUSIONS

The proposed criteria should help clinicians in the classification of their patients and the prospective and retrospective analysis of PNS cases.

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.

Anti-neuronal nuclear autoantibody type 2: paraneoplastic accompaniments

We identified the IgG autoantibody ANNA-2 ("anti-Ri") in 34 patients in a 12-year period by immunofluorescence screening of sera from approximately 75000 patients with subacute neurological disorders that were suspected to be paraneoplastic. Detailed clinical information was available for 28 patients (10 men, 18 women). Cancer was diagnosed in 24 patients (86%); 21 had histologically proven carcinoma (10 lung, 9 breast, 1 cervical, 1 bladder), and 3 had an intrathoracic imaging abnormality. Cancer anteceded neurological symptoms in 4 of 28 patients. Cancer detection frequency increased with continued surveillance. Neurological disorders, in decreasing frequency, were brainstem syndrome (including opsoclonus, myoclonus, or both), cerebellar syndrome, myelopathy, peripheral neuropathy, cranial neuropathy, movement disorder, encephalopathy, Lambert-Eaton syndrome, and seizures. Four patients had laryngospasm and four had jaw opening dystonia (two with neck dystonia). Nine (32%) were wheelchair-bound 1 month after neurological symptom onset. Most improved neurologically after immunomodulatory or tumor-directed therapy. Accompanying autoantibodies, found in 73% of sera, included ANNA-1, ANNA-3, CRMP-5-IgG, P/Q-type and N-type Ca(2+) channel antibodies, and muscle-type acetylcholine receptor antibody. Some neurological accompaniments of ANNA-2 may reflect potentially pathogenic humoral or cell-mediated responses to coimmunogenic tumor antigens, for example, Lambert-Eaton syndrome (P/Q-type Ca(2+) channel antibody) and peripheral neuropathy (ANNA-1 effector T cells).

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

Paraneoplastic cerebellar degeneration (PCD) is a rare, severely debilitating disease, often with a rapid onset and progression, which predate the diagnosis of malignancy. Despite characteristic features, diagnosis is commonly difficult and successful therapy, which relies on early instigation of treatment, is rare. Here we present a patient in whom anti-Yo antibody-positive PCD was associated with endometrial carcinoma and an extensive review of the literature outlining the clinical features, pathogenesis and treatment of PCD.

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.

Low titre autoantibodies against recoverin in sera of patients with small cell lung cancer but without a loss of vision

To date, many authors have described the presence of autoantibodies against various neuronal proteins, paraneoplastic antigens (PNA), in a serum of patients with different kinds of malignant tumors located outside the nervous system. These autoantibodies may cross-react with the corresponding PNA or their epitopes present in neurons and thus initiate the development of a variety of neurological disorders, paraneoplastic syndromes (PNS), even though the primary tumor and its metastases have not invaded the nervous system. Cancer-associated retinopathy (CAR) is a rare ocular PNS induced by autoantibodies against several retinal antigens, one of which is a photoreceptor calcium-binding protein, recoverin. Only several CAR patients with a few kinds of cancer (endothelial carcinoma, breast cancer, epithelial ovarian carcinoma) have so far been found to contain autoantibodies against recoverin in their sera. As for lung cancer, the majority of CAR cases mediated by anti-recoverin autoantibodies have been revealed in patients with the most malignant lung cancer, small cell lung carcinoma (SCLC), and only one similar case has been described for a patient with non-small lung carcinoma. The common feature of all these anti-recoverin-positive patients, irrespective of the type of cancer, is the presence of both the CAR syndrome and high titres (as a rule, more than 1:1000) of the underlying autoantibodies in their serum. In this study, we have used recombinant myristoylated recoverin to screen serum samples of 50 patients with SCLC by Western blot and revealed 5 individuals with low titres of anti-recoverin antibodies, who have no manifestation of a loss of vision. To our knowledge, this is the first report on the presence of low titre autoantibodies against recoverin in a serum of patients with cancer, but without visual dysfunction.

Cancer and autoimmunity: autoimmune and rheumatic features in patients with malignancies

OBJECTIVES

To review the autoimmune and rheumatic manifestations of patients with malignancy.

METHODS

A Medline search of all published papers using keywords related to malignancies, autoimmunity, rheumatic diseases, and paraneoplastic syndromes.

RESULTS

Patients with malignant diseases may develop autoimmune phenomena and rheumatic diseases as a result of (a) generation of autoantibodies against various autoantigens, including oncoproteins (P185, 1-myc, c-myc, c-myb), tumour suppression genes (P53), proliferation associated antigens (cyclin A, B1, D1, E; CENP-F; CDK, U3-RNP), onconeural antigens (Hu, Yo, Ri, Tr), cancer/testis antigens (MAGE, GAGE, BAGE, SSX, ESO, SCP, CT7), and rheumatic disease associated antigens (RNP, Sm). The clinical significance of the various autoantibodies is not clear. Anti-oncoprotein and anti-tumour suppression gene antigens are detected before the diagnosis of the cancer or in the early stages of the malignant disease, suggesting a potential diagnostic or prognostic role. Anti-onconeural antibodies are pathogenic and are associated with specific clinical neurological syndromes (anti-Hu syndrome and others). (b) Paraneoplastic syndromes, a wide range of clinical syndromes, including classic autoimmune rheumatic diseases that develop among patients with cancer. (c) Rheumatism after chemotherapy, a clinical entity characterised by the development of musculoskeletal symptoms after combination chemotherapy for malignancy.

CONCLUSION

Autoimmune and rheumatic features are not rare among patients with malignancies. They are the result of various diverse mechanisms and occasionally they may be associated with serious clinical entities.

Anti-Ri-associated paraneoplastic opsoclonus-ataxia syndrome in a man with transitional cell carcinoma

BACKGROUND

There are several case reports describing paraneoplastic syndromes in patients with various forms of bladder carcinoma. Current immunologic analyses have enabled the identification of the antineuronal autoantibodies associated with specific syndromes.

METHODS

A patient with a history of bladder carcinoma presented with opsoclonus and myoclonus.

RESULTS

Workup confirmed the presence of anti-Ri antibodies in the patient's serum and cerebrospinal fluid. The target Ri antigen was found to be expressed by the tumor.

CONCLUSIONS

To the authors' knowledge, there are few reports in the literature describing the long-term clinical follow-up and postmortem evaluation in a patient with this form of paraneoplastic syndrome. More important, the authors believe the current study represents the first time that the presence of anti-Ri antibodies has been noted in a paraneoplastic syndrome associated with transitional cell carcinoma of the bladder.

[Paraneoplastic subacute cerebellar degeneration: case report]

We report a 40-year-old woman with subacute cerebellar degeneration associated with ovarian cancer. We briefly review the clinical and laboratory features of this syndrome, and emphasize the importance of its prompt recognition, which many times makes possible the early detection and treatment of the primary disorder.

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.