Chemotherapy treatment for anti-Hu paraneoplastic syndrome without active malignancy

INTRODUCTION: Anti-Hu associated paraneoplastic neurological syndromes are rare and characterized by poor prognosis. The research and treatment of a related cancer, a small-cell lung cancer most of the time, remains the best therapeutic strategy. CASE REPORT: We describe the clinical course of a paraneoplastic subacute sensory neuronopathy associated with anti-Hu antibodies in a male smoker treated by an early chemotherapy active against a small-cell lung cancer although no tumor could be found at repeated evaluations. In spite of this treatment, the neurological state deteriorated with the appearance of a cerebellar degeneration, and limbic encephalitis which resulted in a loss of autonomy. A small-cell lung cancer was found and treated 65 months after the onset of the neurological symptoms. The treatment of the underlying malignancy, when it can be found, is still considered as the optimal treatment for paraneoplastic neurological syndromes. Although no tumor could be found, we treated our patient with an empirical chemotherapy active against the most frequent malignancy associated to anti-Hu syndrome in a smoker man, without any improvement. CONCLUSION: Active and repeated research for a cancer related to an anti-Hu neurological syndrome and its treatment are undispensable. For our patient without any identified cancer empirical chemotherapy treatment was unable to stop neurological worsening. When no tumor can be identified by conventional imaging techniques, an early FDG-PET scan should be considered and then repeated if normal.     

Anti-Hu antibodies in Merkel cell carcinoma

Anti-Hu antibody is an antineuronal autoantibody found in a subset of patients with paraneoplastic neurological disease. The antibody was first associated with small cell carcinoma of the lung and is most often used as a marker for this neoplasm in patients presenting with suspected paraneoplastic syndromes. Here we report a patient with a multifaceted neurological disorder in the setting of Merkel cell carcinoma. The patient's serum contained antibodies against the Hu antigen, and the expression of the Hu antigen was demonstrated in the patient's tumor.     

Anti-neuronal antibodies and central nervous system diseases: contribution to diagnosis and pathophysiology

Antibodies against antigens found in the central nervous system have been evidenced in several neurological diseases. The most well-known are associated with paraneoplastic neurological diseases (Anti-Hu, Yo, Ri amphiphysin, Tr, CV2 and Ta antibodies). Some of these antibodies are specific for certain types of cancer or neurological syndromes and are highly useful diagnostic tools for the clinician. They have contributed to the hypothesis that these paraneoplastic neurological syndromes involve autoimmune cross reactions between tumoral and nervous system antigens. They are however most unlikely pathogenic on their own. Anti voltage-dependent calcium channel antibodies associated with Lambert-Eaton syndrome which is paraneoplastic in only 60 p. 100 of the cases are also observed in cases of paraneoplastic cerebellar atrophy. Anti-GAD antibodies are seen in non-paraneoplastic stiff man syndrome and in certain progressive cerebellar atrophies. Antibodies reacting with different glutamate receptors are detected in different neurological diseases including Rasmussen's encephalitis. Finally, antibodies are described in diverse conditions such as amyotrophic lateral sclerosis, Sydeham chorea or Gilles de la Tourette syndrome. The significance of the antibodies observed outside the context of paraneoplastic syndromes is not well understood, but the anti-GAD antibodies associated with progressive cerebellar disorders and autoimmune polyendocrinopathies could be an expression of the autoimmune nature of certain neurological degenerative processes affecting the central nervous system.     

Limbic encephalitis with antibodies to glutamic acid decarboxylase presenting with brainstem symptoms

Limbic encephalitis (LE) is a neurological syndrome that may present in association with cancer, infection, or as an isolate clinical condition often accompanying autoimmune disorders. LE associated with glutamic acid decarboxylase antibodies (anti-GAD) is rare in children. Here, we characterized the clinical and laboratory features of a patient presenting with brainstem involvement with non-paraneoplastic LE associated with anti-GAD antibodies. In our patient, after plasma exchange, we determined a dramatic improvement of the neurological deficits.     

Bickerstaff's brainstem encephalitis complicating Salmonella Paratyphi A infection

Patients with enteric fever frequently develop neurological complications during their illness. Among them, majority has encephalopathy, but focal deficits or peripheral nervous involvements are occasionally encountered. We describe a young woman who developed a neurological syndrome consistent with Bickerstaff's brainstem encephalitis, with symptoms and signs including convulsion, impaired consciousness, external ophthalmoplegia, ataxia, bulbar palsy and pyramidal signs, following Salmonella Paratyphi A infection. This is the first case report of this syndrome after S. Paratyphi A infection, and it is the second case of Bickerstaff's brainstem encephalitis complicating enteric fever reported in the literature. This case also demonstrated, for the first time, a positive anti-GQ1b IgG response in a patient with Bickerstaff's brainstem encephalitis and related disorders that appear as complications during enteric fever.     

Anti-Ri paraneoplastic syndrome associated with ophtalmoplegia, blepharospasm and palilalia

INTRODUCTION: Anti-Hu and anti-Yo are the most well-known anti-neuronal antibodies. The anti-Ri antibodies, which are less common, are generally found in subjects with opsoclonus-myoclonus, often associated with breast cancer. CASE REPORT: A 54-year-old woman presented anti-Ri antibodies associated with a paraneoplastic syndrome and unusual symptoms of ophthalmoplegia, blepharospasm, palilalia and ataxia. Adenocarcinoma of the breast was also found. After chemotherapy, radiotherapy, and several immunoglobulin infusions, the patient did not improve ten months after tumor surgery. CONCLUSION: Anti-Ri antibodies associated with paraneoplastic syndrome can be observed in patients who develop a rapidly progressive brainstem tumor. Breast or lung cancer and conduct to search a breast or pulmonary cancer.     

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

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

Bickerstaff brainstem encephalitis associated with Mycoplasma pneumoniae infection

Bickerstaff brainstem encephalitis is a clinical syndrome of ophthalmoplegia, cerebellar ataxia, and central nervous system signs and is associated with the presence of anti-GQ1b antibodies. There is a clinical continuum between Bickerstaff brainstem encephalitis and Miller Fisher syndrome. We describe the case of an 11-year-old boy with encephalopathy, external ophthalmoplegia, brainstem signs, and ataxia with raised titers of anti-GQ1b antibodies. He presented following a respiratory illness and had laboratory evidence of recent infection with Mycoplasma pneumoniae. M pneumoniae infection has been associated with both Bickerstaff brainstem encephalitis and Miller Fisher syndrome. This is only the second case in the literature of Bickerstaff brainstem encephalitis with raised titers of anti-GQ1b antibodies described in association with M pneumoniae infection. The patient responded to intravenous immunoglobulin administration.     

Anti-Ma2 Paraneoplastic Encephalitis in Association with Recurrent Cervical Cancer

Background

Paraneoplastic neurological syndromes are rare, and although they are frequently associated with gynecological malignancies, cervical cancer is a rare cause. The symptoms of anti-Ma2 encephalitis are diverse and often present prior to the diagnosis of malignancy.

Case Report

We report a case of a 37-year-old woman with a history of cervical cancer presenting with unexplained weight gain and vertical supranuclear gaze palsy. Magnetic resonance imaging of the brain revealed lesions within the bilateral hypothalami and midbrain. Anti-Ma2 antibodies were eventually found in the serum, prompting a search for malignancy. Recurrent metastatic cervical cancer was found in the retroperitoneal lymph nodes.

Conclusions

This is the first report of cervical cancer in association with anti-Ma2 encephalitis, and highlights the need for a high degree of suspicion in patients with a cancer history presenting with neurological symptoms. The symptoms associated with anti-Ma2 encephalitis are diverse and typically precede the diagnosis of cancer in patients, and should trigger a search for an underlying malignancy.     

Bickerstaff’s brainstem encephalitis: can it recur?

Bickerstaff's brain-stem encephalitis is usually a monophasic post-viral inflammatory illness characterized by progressive ophthalmoplegia, ataxia and disturbance of consciousness (or hyper-reflexia). Since the clinical spectrum of Bickerstaff encephalitis may overlap with the Miller-Fisher and Guillain-Barré syndromes, the presence of anti- GQ1b antibodies and abnormal brain MRI can help to support its diagnosis. However, absence of anti-GQ1b antibodies and normal MRI do not exclude the diagnosis, which remains based on clinical criteria and exclusion of other etiologies. We report a case of recurrent Bickerstaff's brainstem encephalitis with no identifiable antecedent illness, and overlapping features of Miller Fisher and Guillain-Barré syndromes, in the presence of negative anti-GQ1b antibodies and repeatedly normal MRI of the brain.     

Síndromes neurológicos paraneoplásicos asociados a anticuerpos anti-Ma y anti-Ma2

Objective

Analyse the clinical profile, associated tumour types, and response to treatment of paraneoplastic neurological syndromes associated with antibodies against Ma proteins.

Paraneoplastic neurological syndromes in patients with carcinoid

Background: Paraneoplastic neurological syndromes (PNS) are mainly associated with small‐cell lung cancer, gynaecological tumours and lymphomas. Few studies report the association of neurological syndromes with a carcinoid, the majority being a serotonin‐related myopathy. We report four patients with a PNS associated with carcinoid. Patients and results: The clinical syndromes were sensory neuropathy, limbic encephalitis, myelopathy and brain stem encephalitis. Two patients had antineuronal autoantibodies (one anti‐Hu, one anti‐Yo), one patient had antinuclear antibodies, and one patient had no autoantibodies. For two of the carcinoids, expression of HuD in the tumour could be demonstrated. Conclusion: This study demonstrates that carcinoids can also be associated with classical antineuronal antibody‐associated PNS.     

Spectrum of neurological diseases associated with antibodies to minor gangliosides GM1b and GalNAc-GD1a

The authors reported the neurological disease spectrum associated with autoantibodies against minor gangliosides GM1b and GalNAc-GD1a. IgG and IgM antibody reactivity against gangliosides GM1, GM2, GM1b, GD1a, GalNAc-GD1a and GQ1b was investigated in sera from 7000 consecutive patients who had various neurological conditions. The clinical diagnoses for 456 anti-GM1b-positive patients were Guillain-Barré syndrome (GBS, 71%), atypical GBS with preserved deep tendon reflexes (12%), Fisher syndrome (10%), Bickerstaff's brainstem encephalitis (2%), ataxic GBS (2%) and acute ophthalmoparesis (1%). For 193 anti-GalNAc-GD1a-positive patients, the diagnoses were GBS (70%), atypical GBS (16%), Fisher syndrome (10%) and Bickerstaff's brainstem encephalitis (3%). Of the patients with GBS or atypical GBS, 28% of 381 anti-GM1b-positive and 31% of 166 anti-GalNAc-GD1a-positive patients had neither anti-GM1 nor anti-GD1a antibodies. Of those patients with Fisher syndrome, Bickerstaff's brainstem encephalitis, ataxic GBS or acute ophthalmoparesis, 33% of 67 anti-GM1b-positive, and 52% of 25 anti-GalNAc-GD1a-positive patients had no anti-GQ1b antibodies. Autoantibodies against GM1b and GalNAc-GD1a are associated with GBS, Fisher syndrome and related conditions. These antibodies should provide useful serological markers for identifying patients who have atypical GBS with preserved deep tendon reflexes, ataxic GBS, Bickerstaff's brainstem encephalitis or acute ophthalmoparesis, especially for those who have no antibodies to GM1, GD1a or GQ1b. A method to prepare GM1b was developed.     

Antiamphiphysin antibodies are associated with various paraneoplastic neurological syndromes and tumors

BACKGROUND: Antiamphiphysin antibodies react with a 128-kd protein found in synaptic vesicles.They were first described in patients with paraneoplastic stiff-man syndrome and breast cancer, but studies suggest that they can also occur in patients with other tumors and neurological disorders. OBJECTIVE: To determine if antiamphiphysin antibodies are associated with various paraneoplastic neurological syndromes and tumors. PATIENTS AND METHODS: Of 2800 serum samples tested by routine immunohistochemical procedures on sections of paraformaldehyde-fixed rat brain for the detection of autoantibodies associated with paraneoplastic neurological syndromes, 5 were selected because of labeling suggestive of antiamphiphysin antibodies and subsequently confirmed by the results of Western blot analysis using recombinant amphiphysin protein. Controls consisted of 40 patients with various nonparaneoplastic neurological diseases; 101 patients with cancer but without paraneoplastic neurological syndrome; 9 patients with small cell lung cancer, anti-Hu antibodies, and paraneoplastic neurological syndrome; 3 patients with M2-type antimitochondrial antibodies but no neurological disorder; and 30 normal subjects. RESULTS: Of the 5 patients with antiamphiphysin antibodies, patient 1 had sensory neuronopathy, encephalomyelitis, and breast cancer; patient 2 had limbic encephalitis, and small cell lung cancer was detected in the mediastinum after 24 months of follow-up; patient 3 had encephalomyelitis and ovarian carcinoma; and patients 4 and 5 had Lambert-Eaton myasthenic syndrome and small cell lung cancer (patient 4 subsequently developed cerebellar degeneration). None of the 5 had stiffness. Two patients (Nos. 2 and 4) had antimitochondrial antibodies. The two patients (Nos. 4 and 5) with Lambert-Eaton myasthenic syndrome had antibodies directed against the voltage-gated calcium channel, and patient 2 subsequently developed anti-Hu antibodies. In the controls, antiamphiphysin antibodies were detected by Western blot analysis in 3 of 8 patients with anti-Hu antibodies, but in none of the other groups. CONCLUSIONS: These data indicate that antiamphiphysin antibodies are not specific for one type of tumor or one neurological syndrome and can be associated with other neural and nonneural antibodies. The simultaneous association of several antibodies in some patients suggests multimodal autoantibody production.     

Anti-GAD antibodies in paraneoplastic cerebellar ataxia associated with limbic encephalitis and autonomic dysfunction

IntroductionCerebellar ataxia and stiff person-syndrome are the main neurological syndromes associated with antibodies to glutamic acid decarboxylase (GAD).Case reportA 59-year-old patient, with history of polymyalgia rheumatica and active smoking, was admitted for subacute cerebellar ataxia and memory dysfunction explained by limbic encephalitis on brain MRI. He also presented with orthostatic hypotension and erectile dysfunction revealing autonomic dysfunction. CSF was inflammatory and antibodies to GAD were positive. Onconeuronal antibodies including GABA_B receptor antibodies were negative. Patient's condition quickly improved after intravenous immunoglobulins. A few months later, a small cell lung carcinoma was diagnosed and precociously treated.ConclusionThis case report underlines the importance of appropriate studies to confirm a primitive neoplasia, when confronted with limbic encephalitis and cerebellar ataxia, even if anti-GAD antibodies rarely define paraneoplastic syndromes.     

BR serine/threonine kinase 2: a new autoantigen in paraneoplastic limbic encephalitis

We describe a new antigen, BR serine/threonine kinase 2 (BRSK2), identified by an antibody present in the serum of a patient with limbic encephalitis and small-cell lung cancer (SCLC). Patient's serum immunolabeled the neuronal cytoplasm and, less intense, the neuropil of rat brain but did not immunoreact with other rat tissues with the exception of testis. Immunoblots of rat brain homogenate identified several immunoreactive bands in the range of 88-82 kDa and a weaker broad band of 47-43 kDa. Probing a rat hippocampus expression library with the patient's serum resulted in the isolation of BR serine/threonine kinase 2 (BRSK2), a protein (also know as SAD1B kinase) preferentially expressed in the brain and testis and implicated in neuronal polarization as well as synaptic development. Eluted IgG from the BRSK2 clone gave a similar immunolabeling than the patient's serum by immunohistochemistry and immunoblot of rat brain and testis. BRSK2 antibodies reacted with two SCLC from patients without paraneoplastic neurological syndromes. No anti-BRSK2 antibodies were found in the serum of 50 patients with SCLC without PNS, 19 with limbic encephalitis without onconeural antibodies, 50 with anti-Hu antibodies and several paraneoplastic neurological syndromes, including 14 with limbic encephalitis, and 160 with a variety of non-paraneoplastic neurological syndromes. Our study suggests BRSK2 may be an autoantigen involved in the pathogenesis of SCLC-associated limbic encephalitis.     

Paraneoplastic neurological disorders

The article provides an overview on the diagnosis and pathogenesis of paraneoplastic neurological disorders (PNDs), and subsequently the current therapeutic strategies in these patients. PNDs are nervous system dysfunctions in cancer patients, which are not due to a local effect of the tumor or its metastases. Most of these clinically defined syndromes in adults are associated with lung cancer, especially small-cell lung cancer, lymphoma and gynecological tumors. In a part of the PND, an overlapping of different clinical syndromes can be observed. Highly specific autoantibodies directed against onconeuronal antigens led to the current hypothesis of an autoimmune pathophysiology. Whereas the most central nervous PNDs are more T-cell-mediated, limbic encephalitis can be caused by pathogenic receptor autoantibodies. The PND of the neuromuscular junction and paraneoplastic autonomic neuropathy are mainly associated with receptor or ion channel autoantibodies. The childhood opsoclonus-myoclonus syndrome and the PNDs associated with receptor/ion channel autoantibodies often respond to immunosuppressive therapies, plasmapheresis and intravenous immunoglobulins. By contrast, most CNS PNDs associated with defined antineuronal antibodies directed against intracellular antigens only stabilize after tumor treatment.     

Autoimmune encephalitis: Recent updates and emerging challenges

The knowledge of immune dysregulation and autoimmunity in neurological disorders has expanded considerably in recent times. Recognition of clinical syndromes, reliable methods of diagnosis, and early targeted immunotherapy can lead to a favourable outcome in acute and subacute neurological disorders that may be associated with significant morbidity and mortality if left untreated. This review focuses on the rapidly expanding field of autoimmune encephalitis. We describe the differences between limbic encephalitis associated with antibodies targeting intracellular antigens, and neuronal surface antibody syndromes (NSAS) where the antigens are primarily receptors or synaptic proteins located on the neuronal cell surface. We chronologically highlight important developments in NSAS by focusing on voltage gated potassium channel complex-associated antibody mediated encephalitis, anti-N-methyl-d-aspartate receptor (anti-NMDAR) encephalitis, and anti-dopamine 2 receptor antibody-associated basal ganglia encephalitis. Contentious issues such as the complexities of using serum antibodies as biomarkers, the initiation of central nervous system autoimmunity, and possible pathogenic mechanisms of these antibodies will be reviewed. The therapeutic challenges that clinicians face such as the timing of therapy and the role of second-line therapy will be discussed, with crucial concepts highlighted in the form of clinical vignettes. Future directions will involve the identification of novel antigens and methods to establish their pathogenicity, as well as evaluation of the most efficacious therapeutic strategies in patients with established NSAS.     

Antibodies and neuronal autoimmune disorders of the CNS

We review the neuronal antibodies described in CNS disorders in order to clarify their diagnostic value, emphasize potentials pitfalls and limitations in the diagnosis of paraneoplastic neurological syndromes (PNS), and examine the current evidence for a possible pathogenic role. We propose to classify the neuronal antibodies associated with syndromes resulting from CNS neuronal dysfunction into two groups according to the location of the antigen: inside the neuron or in the cell membrane. Group I includes antibodies which target intracellular antigens and probably are not pathogenic. They are further subdivided into three groups. Group Ia comprises well-characterized onconeural antibodies (Hu (ANNA1), Yo (PCA1), Ri (ANNA2), CV2 (CRMP5), amphiphysin, Ma2) that are useful for the diagnosis of PNS. Group Ib antibodies (SOX and ZIC) are cancer-specific but there is no evidence that the immune response is in any way pathogenically related to the PNS. Antibodies in group Ic (glutamic acid decarboxylase (GAD), adenylate kinase 5 and Homer 3) identify non-PNS: stiff-person syndrome (SPS), cerebellar ataxia, and limbic encephalitis (LE). Group II antibodies recognize neuronal surface antigens. Antibodies in group IIa associate with characteristic CNS syndromes but their detection does not indicate that the disorder is paraneoplastic. Antibodies to potassium channels, AMPA and GABA_B receptors are associated with LE, NMDA receptor antibodies identify a well-defined encephalitis, and antibodies against glycine receptors associate with SPS with encephalitis. A pathogenic role of the antibodies is suggested by the response of symptoms to immunotherapy and the correlation between antibody titers and neurological outcome. Lastly, Group IIb includes antibodies that are found in patients with paraneoplastic cerebellar ataxia associated with lung cancer (P/Q type calcium channels antibodies) or Hodgkin disease (metabotropic glutamate receptor type 1 antibodies).