Neurological course of long-term surviving patients with SCLC and anti-Hu syndrome

Patients with small-cell lung cancer (SCLC) have a poor prognosis with a three year survival rate of 4%. Our report concerns three patients with histologically proven SCLC and anti-Hu associated paraneoplastic neurological syndrome who have survived for 11 in two cases and 16 years respectively. The patients showed progressive deterioration which was only partly beneficially modulated by steroid therapy or tumor treatment, even in the cases with complete tumor remission.

[P/Q-type voltage-dependent calcium channels in neurological disease]

INTRODUCTION

Voltage-dependent calcium channels (VDCC) are hetero-multimeric complexes that mediate calcium influx into cells in response to changes in membrane potential. The alpha1A subunit, encoded by the CACNA1A gene, is the pore-forming structure specific to the neuronal P/Q-type voltage-dependent calcium channels (P/QCC), present exclusively in neurons. The ancillary subunits beta, alpha2delta and gamma, which are common to other VDCC, modulate alpha1A activity. P/QCC are involved in neuronal plasticity and survival, and mediate fast neurotransmission in the central and peripheral nervous system. Their highest levels of expression are found in the Purkinje cell layer of the cerebellum and in the hippocampus.

METHODS

Congenital and acquired disturbances of the P/QCCs lay behind some neurological diseases, such as spinocerebellar ataxia type 6, episodic ataxia type 2 and paraneoplastic cerebellar degeneration; familial hemiplegic migraine; generalized convulsive epilepsy, generalized absence epilepsy and myasthenic syndrome of Lambert-Eaton.

CONCLUSION

In this article, the structure and modulation of normal P/QCCs, and the neurological diseases caused by disturbances in these are reviewed. Electrophysiological characterization of mutated P/QCCs has yielded decreased calcium conductance in every case, compared with wild type channels. Research about calcium channelopathies should clarify how altered channel function produces disease and lead to new treatments for these conditions.

Central hypoventilation as the presenting symptom in Hu associated paraneoplastic encephalomyelitis

Central hypoventilation is usually caused by ischaemic or neoplastic lesions of the medulla and upper cervical spinal cord. An autoimmune disorder is not usually considered in the differential diagnosis of this syndrome. We retrospectively identified 14 patients from our database of 202 patients with Hu antibodies who presented with brainstem symptoms. Three were admitted to hospital because of central hypoventilation. All underwent intubation and mechanical ventilation. They could breathe properly while they were awake but suffered deep apnoeas during sleep. Two died, but one is still alive requiring ventilatory assistance during sleep. Autopsy was performed in one of the patients which showed severe inflammatory infiltrates and neuronal loss in the medulla. All patients had normal brain imaging studies and the cause of central hypoventilation was an unsolved problem until Hu antibodies were determined.

Syndromes neurologiques paranéoplasiques

The classic paraneoplastic neurological syndromes include Lambert-Eaton myasthenic syndrome, limbic encephalitis, sensory neuronopathy, intestinal pseudo-obstruction, subacute cerebellar degeneration, encephalomyelitis, and dermatomyositis. Approximately ten onconeural antibodies that recognize cancer and the nervous system have been described in paraneoplastic neurological syndromes. These antibodies appear to be important diagnostic tools, even though they may not always be present. Deciding whether a given neurological picture is definitely or possibly paraneoplastic depends on the clinical syndrome, any association with onconeural antibodies, and the time elapsed between onset of neurological symptoms and the discovery of the cancer. Diagnosis of a classic paraneoplastic neurological syndrome or the discovery of onconeural antibodies mandates an active and persistent search for cancer, using new techniques such as fluorodeoxyglucose positron emission tomography. In patients with one of these syndromes, the best treatment of the neurological disease is often the diagnosis and early treatment of the cancer.

Autoantibodies against glial antigens in paraneoplastic neurological diseases

Paraneoplastic neurological syndromes are clinically heterogeneous manifestations of cancer, but are not caused by the tumor or its metastases. Because autoantibodies reacting with tumor and nervous system tissue have been described, an autoimmune pathogenesis is suspected. Most autoantibodies are directed against neuronal proteins. Here, we describe the impact of antiglial autoantibodies in paraneoplastic neurological syndromes. Anti-CRMP5 and antiglial nuclear antibody both can be associated with different paraneoplastic neurological syndromes and tumors.

A patient with encephalitis associated with NMDA receptor antibodies

BACKGROUND

A 34-year-old woman presented with headache, feverish sensation and anxiety, rapidly followed by homicidal ideation, aggressive agitation, seizures, hypoventilation, hyperthermia and prominent autonomic instability requiring intubation and sedation. She developed episodes of hypotension and bradycardia with periods of asystole lasting up to 15 seconds. Upon weaning off sedation, her eyes opened but she was unresponsive to stimuli. There was muscle rigidity, frequent facial grimacing, rhythmic abdominal contractions, kicking motions of the legs, and intermittent dystonic postures of the right arm.

INVESTIGATIONS

Routine laboratory testing, toxicology screening, studies for autoimmune and infectious etiologies, brain MRI scan, lumbar puncture, electroencephalogram, whole-body CT scan, abdominal ultrasound, paraneoplastic and voltage-gated potassium channel antibody serologies, analysis of N-methyl-D-aspartate receptor antibodies.

DIAGNOSIS

Paraneoplastic encephalitis associated with immature teratoma of the ovary and N-methyl-D-aspartate receptor antibodies.

MANAGEMENT

Intensive care, mechanical ventilation, antiepileptics, laparotomy and left salpingo-oophorectomy, corticosteroids, plasma exchange, intravenous immunoglobulin, cyclophosphamide, physical therapy, and chemotherapy.

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.

Absence of paraneoplastic antineuronal antibodies in sera of 145 patients with motor neuron disease

BACKGROUND

Well characterised antineuronal antibodies (ANAbs) have been shown to be highly specific markers of neurological syndromes with a paraneoplastic aetiology. Previous reports indicate that pure motor neuron disease (MND) is rarely of paraneoplastic origin.

OBJECTIVE

To screen systematically for the prevalence of well characterised paraneoplastic ANAbs in a large collective of patients with pure MND.

METHODS

In a cohort of 145 patients with MND, the frequency of ANAbs was estimated by ELISA, employing recombinant antigens (HuD, Yo, Ri, CV2/CRMP5, Ma2 and amphiphysin).

RESULTS

None of the sera revealed high antineuronal antigen reactivity. Very low reactivity was detected in only five sera, in all probability representing background activity.

CONCLUSION

According to these data, routine analysis for ANAbs in patients with isolated MND is not mandatory.

Antigen-specific oligoclonal bands in cerebrospinal fluid and serum from patients with anti-amphiphysin- and anti-CV2/CRMP5 associated paraneoplastic neurological syndromes

Using isoelectric focusing and affinity blotting employing paraneoplastic recombinant antigens, we investigated cerebrospinal fluid (CSF) and sera from three patients with positive anti-CV2/CRMP5- and one patient with positive anti-amphiphysin serology. CSF and sera were previously adjusted to total IgG concentrations of 20 mg/l. All patients suffered from paraneoplastic neurological syndromes (PNS) with predominant involvement of the central nervous system (CNS). Using affinity blot preloaded with paraneoplastic antigen, we detected in three of four patients more or stronger specific oligoclonal bands (OCB) in the CSF than in the corresponding serum, providing qualitative evidence of antigen specific intrathecal antibody synthesis. These results are in line with previous studies demonstrating specific OCB predominantly in CSF from patients with anti-Hu-, anti-Yo- and anti-Ri-associated PNS, supporting the hypothesis of autoimmunity in the pathogenesis of PNS. One patient harboured extensive anti-amphiphysin specific OCB, although OCB of total IgG could not be detected, indicating a higher sensitivity for detection of intrathecal antibody synthesis of the affinity blot preloaded with the paraneoplastic antigen, compared with investigation of total IgG OCB. These results could have implications concerning pathophysiological autoimmune aspects in other inflammatory diseases of CNS associated with total IgG OCB, provided that the target antigen is known.

Diagnosis and current treatment of neurological paraneoplastic syndromes

Neurological paraneoplastic syndromes (NPS) affect only 0.01% of cancer patients, chiefly those affected by lung, breast, ovarian and stomach cancer. They frequently cause major disability and produce limitations in patients' daily activities; the character of the disease is irreversible. Clinical suspicion is fundamental for an early diagnosis and it must be backed up by the specification of certain antibodies both present in blood and in cerebrospinal fluid (CSF). Conventional treatments are very inefficient at the time of treating these disorders; at present, the administration of immunoglobulins, immunosuppressors, chemotherapy agents and corticoids are under study, but so far results are not promising. The aim of this review is to analyze the variety of NPS and describe the findings concerning autoimmunity and treatments used at present.

Isolated frontal disequilibrium as presenting form of anti-Hu paraneoplastic encephalomyelitis

Anti-Hu encephalomyelitis is one of the most frequent paraneoplastic syndromes, classically presenting with diffuse neurological involvement. We report a 69-year-old man presenting with a three-month isolated, progressive gait disorder with normal neurological examination, except for loss of balance and gait failure reminding frontal disequilibrium, only accompanied by a very mild rigidity of his right foot. MRI of the brain showed hyperintensities in both amygdale and left putamen. EMG study showed no abnormal continuous spontaneous fiber activity. Because of fast progression and MRI findings, anti-Hu antibodies were tested, resulting positive. Mediastinal biopsy of two adenopathies detected by body-PET, confirmed an oat-cell carcinoma. The patient received oral steroids and oncological therapy. One year later, the tumor is in remission. His gait and abnormal posture of right leg are normal. Only mild residual hyperintensities persist on follow-up MRI. A paraneoplastic syndrome should be considered in the differential diagnosis of subacute, fast progressive gait disorders.

Specific antibody index in cerebrospinal fluid from patients with central and peripheral paraneoplastic neurological syndromes

We evaluated the concentration of antineuronal antibodies in paired cerebrospinal fluid (CSF) and serum samples from 19 patients with central and peripheral paraneoplastic neurological syndromes (PNS), using an enzyme linked immunosorbent assay (ELISA) employing recombinant antineuronal antigens (HuD, Yo, Ri, CV2/CRMP5, amphiphysin, PNMA2/Ma2). The specific antibody index (AI) [Qspec/QIgG] was calculated to estimate specific intrathecal antibody synthesis. An AI>1.3 was considered as evidence of intrathecal specific antibody synthesis. 14 (88%) of 16 patients with exclusive or predominant paraneoplastic involvement of the central nervous system (CNS) showed an AI>1.3, indicating a specific intrathecal antibody synthesis, while all three patients with isolated involvement of the peripheral nervous system showed an AI<0.8. All together, in 17 of 19 patients (89%) we found a significant association (p<0.05) between central or peripheral neurological manifestations on the one hand and presence or absence of specific intrathecal synthesis respectively on the other hand. These data support the hypothesis that autoimmunity is involved in the pathogenesis of PNS.

[Onconeural antibodies as a tool for diagnosis of malignant tumors and paraneoplastic neurological disorders]

Paraneoplastic neurological syndromes (PNS) are autoimmune neurodegenerative diseases that develop as a result of the cross-reactivity of the tumor-specific immune effectors with neurons of central and peripheral nervous systems. So-called onconeural antibodies, which are detected in sera of PNS patients, are not only crucial diagnostic markers of PNS and associated tumors, but also have a considerable potential in the serological diagnosis of cancer as a whole. In this review we discuss the role of onconeural antibodies in serological diagnosis of PNS and associated tumors as well as their potential in diagnosis and prognostication of a broad spectrum of malignant tumors.

Autonomic paraneoplastic neurological syndromes

Autonomic paraneoplastic neurological syndromes (PNS) typically present as chronic gastrointestinal pseudo-obstruction or orthostatic hypotension and usually occur in association with other PNS rather than in isolation. Although rare, they are often debilitating, sometimes fatal, and probably seriously underdiagnosed. Here, we discuss the clinical, immunological and oncological features of these syndromes and review the molecular and cellular mechanism that may underlie the triggering and maintenance of their autoimmune pathogenesis.

An uncontrolled trial of rituximab for antibody associated paraneoplastic neurological syndromes

Anti-CD20 monoclonal antibody (rituximab) is effectively used in the treatment of B-cell lymphomas. Recent reports in the literature suggest that antibody associated autoimmune disorders may respond to rituximab. We therefore treated nine patients with anti-Hu or anti-Yo associated paraneoplastic neurological syndromes (PNS) with a maximum of four monthly IV infusions of rituximab (375mg/m(2)). In this uncontrolled, unblinded trial of rituximab, three patients improved > or =1 point on the Rankin Scale (RS). One patient with limbic encephalitis improved dramatically (RS from 5 to 1). Further studies of rituximab in autoantibody associated PNS are warranted.

Managing paraneoplastic neurological disorders

Paraneoplastic neurological syndromes (PNS) are remote effects of cancer that are not caused by invasion of the tumor or its metastases. Immunologic factors appear important in the pathogenesis of PNS because antineuronal autoantibodies and T-cell responses against nervous system antigens have been defined for many of these disorders. The immunologic response is elicited by the ectopic expression of neuronal antigens by the tumor. Expression of these so-called "onconeural" antigens is limited to the tumor and the nervous system and sometimes also the testis. At the time of presentation of the neurological symptoms, most patients have not yet been diagnosed with cancer. Detection of paraneoplastic antibodies is extremely helpful in diagnosing an otherwise unexplained and often rapidly progressive neurological syndrome as paraneoplastic. In addition, the paraneoplastic antibodies may also direct the search for an underlying neoplasm. On the other hand, in patients known to have cancer, the presentation of a PNS may herald recurrence of the tumor or a second tumor. The number of paraneoplastic antibodies is still growing, and at least seven of these can now be considered well characterized. Based on the clinical syndrome, the type of antibody, and the presence or absence of cancer, patients are classified as having a "definite" or "possible" PNS. Despite the presumed autoimmune etiology of PNS, the results of various forms of immunotherapy have been disappointing, with some exceptions. Rapid detection and immediate treatment of the underlying tumor appears to offer the best chance of stabilizing the patient and preventing further neurological deterioration.

Neuroimmunology of dancing eye syndrome in children

Clinical, histopathological, and laboratory evidence suggest that dancing eye syndrome/opsoclonus-mycoclonus syndrome is an immune-mediated and probably autoimmune disorder. There is a clear, but not invariable, association with neuroblastoma or ganglioneuroma in children, and with a miscellany of neoplasms in adults. Direct support, i.e. the identification of antibodies against cell-surface antigens in neurons, is lacking but the nature of other evidence is such that the case for use of immunomodulatory therapeutic strategies is compelling. Because at least 85% of children affected by the condition are left with permanent cognitive deficits, notwithstanding a favourable initial neurological response to, say, steroid or adrenocorticotrophic hormone, therapeutic stakes are high. There is an urgent need for controlled therapeutic trials which, because of the comparative rarity of the condition in children, will require international collaboration to expedite studies.

An immunoprecipitation assay for the detection of onconeural antibodies

INTRODUCTION

Onconeural antibodies are found in some patients with cancer, and are associated with paraneoplastic neurological syndromes.

METHOD

A multi-well adapted fluid-phase immunoassay using radiolabelled recombinant onconeural proteins for the detection of onconeural antibodies is described.

RESULT AND CONCLUSION

This immunoprecipitation technique is more sensitive in detecting onconeural antibodies than immunohistochemistry and immune blots.

Onconeural antibodies are essential to diagnose paraneoplastic neurological syndromes

Paraneoplastic neurological syndromes (PNS) can be defined as remote effects of cancer that are not caused by the tumor and its metastasis or by infection, ischemia or metabolic disruptions. In most patients, the neurological disorder develops before the cancer becomes clinically overt and the patient is referred to the neurologist who has the charge of identifying a neurological disorder as paraneoplastic. They are usually severely disabling. PNS are rare and are seen in less than 1% of patients with cancer. PNS depend on an autoimmune process triggered by cancer and directed to antigens common to both the cancer and the nervous system designated as onconeural antigens. Because of their high specificity (>90%), the best way to diagnose neurological disorders as paraneoplastic is to identify one of the well-characterized onconeural antibodies in the patient's serum. In addition, as these antibodies are associated with a restricted range of cancer, they permit orientating the search of the underlying tumor at a stage where it is frequently not clinically overt. This is a critical point, as today the best way to stabilize PNS is probably to treat the cancer as soon as possible. Unfortunately, about one-third of the patients do not have detectable antibodies and 5-10% have an atypical antibody that is not well characterized.

cDNA expression library screening for identification of novel onconeural antigens

Paraneoplastic neurological disorders occur as a remote effect of cancer. Tumor cells expressing neuron-specific proteins elicit an autoimmune response, resulting in the production of various antibodies. The antibodies are usually associated with different syndromes, but the identity of many of the antigens is still unknown. Screening a cDNA expression library is a powerful technique that allows identification of previously uncharacterized antigens. By using patient sera containing antibodies, the antigens of interest can be isolated and further characterized.