40 years of autoantibody research in paraneoplastic neurological syndromes.

Paraneoplastic neurologic syndromes (PNS) are a group of disorders that affect the central and the peripheral nervous system and frequently occur in patients with cancer which usually still is undiagnosed by the time the patient presents the first neurological manifestations. The discovery in the serum and cerebrospinal fluid of PNS patients of antibodies that target tumor antigens that also are normally expressed in the nervous system had a significant impact. First, the research on neuronal antibodies confirmed that most PNS are autoimmune disorders triggered by the underlying cancer supporting the use of immunotherapy to treat them; second, although the first antibodies described recognized intracellular neuronal antigens and therefore they were not pathogenic, these antibodies became robust biomarkers for the strict diagnosis of PNS; and third, the methodological approach used to characterize the first neuronal antibodies paved the way to the identification of antibodies against neuronal surface antigens that are pathogenic and responsible for some PNS and non-paraneoplastic encephalitis. Future studies should address several issues: (1) to improve the efficiency of commercial kits; (2) to provide strict criteria to select which neural antibodies should be used for the diagnosis of PNS; and (3) define in more detail the autoimmune mechanisms responsible for the brain injury in the PNS.

Diagnostic delay and outcome in immunocompetent patients with primary central nervous system lymphoma in Spain: a multicentric study.

INTRODUCTION: To assess the management of immunocompetent patients with primary central nervous system lymphomas (PCNSL) in Spain. METHODS: Retrospective analysis of 327 immunocompetent patients with histologically confirmed PCNSL diagnosed between 2005 and 2014 in 27 Spanish hospitals. RESULTS: Median age was 64 years (range: 19-84; 33% ≥ 70 years), 54% were men, and 59% had a performance status (PS) ≥ 2 at diagnosis. Median delay to diagnosis was 47 days (IQR 24-81). Diagnostic delay > 47 days was associated with PS ≥ 2 (OR 1.99; 95% CI 1.13-3.50; p = 0.016) and treatment with corticosteroids (OR 2.47; 95% CI 1.14-5.40; p = 0.023), and it did not improve over the years. Patients treated with corticosteroids (62%) had a higher risk of additional biopsies (11.7% vs 4.0%, p = 0.04) but corticosteroids withdrawal before surgery did not reduce this risk and increased the diagnostic delay (64 vs 40 days, p = 0.04). Median overall survival (OS) was 8.9 months [95% CI 5.9-11.7] for the whole series, including 52 (16%) patients that were not treated, and 14.1 months (95%CI 7.7-20.5) for the 240 (73.4%) patients that received high-dose methotrexate (HD-MTX)-based chemotherapy. Median OS was shorter in patients ≥ 70 years (4.1 vs. 13.4 months; p < 0.0001). Multivariate analysis identified age ≥ 65 years, PS ≥ 2, no treatment, and cognitive/psychiatric symptoms at diagnosis as independent predictors of short survival. CONCLUSIONS: Corticosteroids withdrawal before surgery does not decrease the risk of a negative biopsy but delays diagnosis. In this community-based study, only 73.4% of patients could receive HD-MTX-based chemotherapy and OS remains poor, particularly in elderly patients ≥ 70 years.

Syndrome and outcome of antibody-negative limbic encephalitis.

BACKGROUND AND PURPOSE: The aim was to report the clinical characteristics of 12 patients with limbic encephalitis (LE) who were antibody-negative after a comprehensive immunological study. METHODS: The clinical records of 163 patients with LE were reviewed. Immunohistochemistry on rat brain, cultured neurons and cell-based assays were used to identify neuronal autoantibodies. Patients were included if (i) there was adequate clinical, cerebrospinal fluid (CSF) and magnetic resonance imaging information to classify the syndrome as LE, (ii) magnetic resonance images were accessible for central review and (iii) serum and CSF were available and were confirmed negative for neuronal antibodies. RESULTS: Twelve (7%) of 163 LE patients [median age 62 years; range 40-79; 9 (75%) male] without neuronal autoantibodies were identified. The most frequent initial complaints were deficits in short-term memory leading to hospital admission in a few weeks (median time 2 weeks; range 0.5-12). In four patients the short-term memory dysfunction remained as an isolated symptom during the entire course of the disease. Seizures, drowsiness and psychiatric problems were unusual. Four patients had solid tumors (one lung, one esophagus, two metastatic cervical adenopathies of unknown primary tumor) and one chronic lymphocytic leukemia. CSF showed pleocytosis in seven (58%) with a median of 13 white blood cells/mm3 (range 9-25). Immunotherapy included corticosteroids, intravenous immunoglobulins and combinations of both drugs or with rituximab. Clinical improvement occurred in six (54%) of 11 assessable patients. CONCLUSIONS: Despite the discovery of new antibodies, 7% of LE patients remain seronegative. Antibody-negative LE is more frequent in older males and usually develops with predominant or isolated short-term memory loss. Despite the absence of antibodies, patients may have an underlying cancer and respond to immunotherapy.

Anti-Ma and anti-Ma2-associated paraneoplastic neurological syndromes. / 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. METHODS: A retrospective study of patients with antibodies against Ma proteins identified in a neuroimmunology laboratory of reference. RESULTS: Of the 32 patients identified, 20 showed reactivity against Ma2 only (anti-Ma2 antibodies), 11 against Ma1 and Ma2 (anti-Ma antibodies), and 1 with reactivity against Ma1 only (anti-Ma1 antibodies). The most common clinical presentations were limbic encephalopathy, diencephalic dysfunction, or brainstem encephalopathy, frequently appearing as a combination of these features. Three patients had isolated cerebellar dysfunction with anti-Ma antibodies, and 2 exhibited peripheral nervous system syndrome with anti-Ma2 antibodies. Testicular tumours were the most common neoplasms (40%) in the anti-Ma2 cases. In the group associated with anti-Ma1 antibodies, the most common were lung tumours (36%), followed by testicular tumours. All idiopathic cases were reactive to Ma2. The clinical outcome was significantly better in the anti-Ma2 group. The patient with anti-Ma1 presented with limbic encephalitis and brainstem dysfunction associated with lymphoepithelioma of the bladder. CONCLUSIONS: Specifically determining the different reactivities of anti-Ma protein antibodies in order to differentiate between Ma1 and Ma2 antibodies is important because anti-Ma2-associated paraneoplastic syndromes have a better outcome. Lastly, this study is the first to confirm that there may be cases that react exclusively to antibodies against Ma1.

Seizure-susceptible brain regions in glioblastoma: identification of patients at risk.

BACKGROUND AND PURPOSE: The main aim of this study was to identify which patients with glioblastoma multiforme (GBM) have a higher risk of presenting seizures during follow-up. METHODS: Patients with newly diagnosed GBM were reviewed (n = 306) and classified as patients with (Group 1) and without (Group 2) seizures at onset. Group 2 was split into patients with seizures during follow-up (Group 2A) and patients who never had seizures (Group 2B). The anatomical location of GBM was identified and compared by voxel-based lesion symptom mapping (discovery set). Seizure-susceptible brain regions obtained were assessed visually and automatically in external GBM validation series (n = 85). RESULTS: In patients with GBM who had no seizures at onset, an increased risk of presenting seizures during follow-up was identified in the superior frontal and inferior occipital lobe, as well as in inferoposterior regions of the temporal lobe. Conversely, those patients with GBM located in medial and inferoanterior temporal areas had a significantly lower risk of suffering from seizures during follow-up. Additionally, the seizure-susceptible brain region maps obtained classified patients in the validation set with high positive and negative predictive values. CONCLUSIONS: Tumor location is a useful marker to identify patients with GBM who are at risk of suffering from seizures during follow-up. These results may help to support the use of antiepileptic prophylaxis in a selected GBM population and to improve stratification in antiepileptic clinical trials.

Absence of NMDA receptor antibodies in the rare association between Type 1 Narcolepsy and Psychosis.

Frequency and mechanisms underlying the association between narcolepsy type 1 (NT1) and psychosis remain unclear with potential role for a common immune pathway. We estimated the frequency of psychosis and its characteristics in NT1 at two European sleep centers (France, n = 381; Spain, n = 161) and measured IgG autoantibodies that recognize the GluN1 subunit of the NMDAR in 9 patients with NT1 with psychosis, and 25 NT1 patients without psychosis. Ten NT1 patients (6 in France, 4 in Spain) were diagnosed with comorbid psychosis, a frequency of 1.8%. One patient reported psychotic symptoms few months before narcolepsy onset, two patients few months after onset, and one patient one year after onset but after modafinil introduction. The six remaining patients reported long delays between NT1 and psychosis onset. Half the patients, mostly male adults, reported onset or worsening of psychotic symptoms after medication. We found no IgG antibodies to NR1/NR2B heteromers of the NMDARs in patients with NT1 with or without psychosis. To conclude, psychosis is rare in NT1, with limited evidence for a key impact of stimulants, and no association with anti-NMDAR antibodies. However, dramatic NT1 and schizophrenia exists especially in early onset NT1, which may lead to inappropriate diagnosis and management.

Prostate cancer, Hu antibodies and paraneoplastic neurological syndromes.

Prostate cancer is the most common cancer among American and European men. Nervous system affection caused by local tumor growth or osseous metastases are the main causes of neurological symptoms in prostate cancer patients. Prostate cancer is rarely reported in association with paraneoplastic neurological syndromes (PNS). We have, therefore, studied clinical and paraclinical findings of a series of patients with prostate cancer and PNS, and reviewed cases reported in the literature. Case histories of 14 patients with definite PNS from the PNS Euronetwork database and from the authors' databases were reviewed. A PubMed literature search identified 23 patients with prostate cancer and PNS. Thus, a total of 37 case histories were reviewed with respect to syndrome type, cancer evolution, paraclinical investigations, antibody status, treatment and outcome. The three most frequent isolated PNS were paraneoplastic cerebellar degeneration, paraneoplastic encephalomyelitis (PEM)/limbic encephalitis and subacute sensory neuronopathy (SSN). Onconeural antibodies were detected in 23 patients, in most cases the Hu antibody (17 patients, 74 % of all antibody-positive cases). Other well-characterized onconeural antibodies (Yo, CV2/CRMP5, amphiphysin, VGCC antibodies) were found in a minority. PNS was diagnosed prior to prostate cancer diagnosis in 50 % of the cases. The association of PNS with prostate cancer is quite infrequent, but clinically important. PNS often heralds prostate cancer diagnosis. Syndromes associated with Hu antibodies predominate. Another tumor more prone to associate with PNS should always be excluded.

The expanding field of IgG4-mediated neurological autoimmune disorders.

At least 13 different disease entities affecting the central nervous system, peripheral nervous system and connective tissue of the skin or kidneys are associated with immunoglobulin G4 (IgG4) immune reactivity. IgG4 has always been considered a benign, non-inflammatory subclass of IgG, in contrast to the well-known complement-activating pro-inflammatory IgG1 subclass. A comprehensive review of these IgG4 autoimmune disorders reveals striking similarities in epitope binding and human leukocyte antigen (HLA) associations. Mechanical interference of extracellular ligand-receptor interactions by the associated IgG4 antibodies seems to be the common/converging disease mechanism in these disorders.

Clinical spectrum and diagnostic value of antibodies against the potassium channel related protein complex.

INTRODUCTION: Antibodies against a protein complex that includes voltage-gated potassium channels (VGKC) have been reported in patients with limbic encephalitis, peripheral nerve hyperexcitability, Morvan's syndrome, and a large variety of neurological syndromes. REVIEW SUMMARY: In this article, a review is presented of the syndromes associated with antibodies against VGKC-related proteins and the main antigens of this protein complex, the proteins LGI1 (leucine rich glioma inactivated protein 1) and Caspr2 (contactin-associated protein-like 2). The conceptual problems and clinical implications of the description of antibodies against VGKC-related proteins other than LGI1 and Caspr2 are also discussed. Although initial studies indicated the occurrence of antibodies against VGKC, recent investigations have shown that the main antigens are a neuronal secreted protein known as LGI1 which modulates synaptic excitability, and a protein called Caspr2 located on the cell surface and processes of neurons of different brain regions, and at the juxtaparanodal region of myelinated axons. While antibodies against LGI1 preferentially associate with classical limbic encephalitis, antibodies against Caspr2 associate with a wider spectrum of symptoms, including Morvan's syndrome, peripheral nerve hyperexcitability or neuromyotonia, and limbic or more extensive encephalitis. In addition there are reports of patients with antibodies against VGKC-related proteins that are different from LGI1 or Caspr2. In these cases, the identity and location of the antigens are unknown, the syndrome association is not specific, and the response to treatment uncertain. CONCLUSIONS: The discovery of antigens such as LGI1 and Caspr2 has resulted in a clinical and molecular definition of the broad group of diseases previously attributed to antibodies against VGKC. Considering the literature that describes the presence of antibodies against VGKC other than LGI1 and Caspr2 proteins, we propose a practical algorithm for the diagnosis and treatment of these patients.

Seronegative paraneoplastic cerebellar degeneration: the PNS Euronetwork experience.

BACKGROUND AND PURPOSE: To describe the characteristics of patients presenting a paraneoplastic cerebellar degeneration without classical onconeural antibodies (seronegative PCD). METHODS: Thirty-nine seronegative PCD patients from the Paraneoplastic Neurological Syndrome Euronetwork were retrospectively analyzed and compared with 180 patients with PCD associated with classical onconeural antibodies (seropositive PCD). RESULTS: No patient had anti-CASPR2 or anti-mGluR1 antibodies. No significant difference between the clinical characteristics of seronegative and seropositive PCD patients was observed. Yet the frequency of associated tumors was different. Lymphoma was more frequent in seronegative than in seropositive women (24% vs. 2%, P = 0.002) whilst gynecological cancer were less frequent (38% vs. 74%, P = 0.002). In comparison with seropositive men, seronegative men more frequently had a non-small-cell lung cancer (27% vs. 6%, P = 0.08) or a genitourinary cancer (22% vs. 0%, P = 0.04) but less frequently a small-cell lung cancer (23% vs. 74%, P = 0.002). Seronegative and seropositive PCD patients with similar tumors had a similar overall survival. CONCLUSION: The clinical characteristics of seronegative and seropositive PCD are similar but the spectrum of associated tumors is different. The immunological scenario of seronegative PCD seems to be different from that of limbic encephalitis with only few patients harboring anti-neuropile antibodies.

[Fast and spectacular clinical response to plasmapheresis in a paediatric case of anti-NMDA encephalitis]. / Respuesta clinica rapida y espectacular a plasmaferesis en un caso pediatrico de encefalitis anti-NMDA.

INTRODUCTION: Autoimmune encephalitis against N-methyl-D-aspartate (NMDA) receptors is being diagnosed more and more frequently in the paediatric age. It should be suspected in children with psychiatric symptoms, encephalopathy, abnormal movements or epileptic seizures. Paraneoplastic cases are less frequent than in adults. CASE REPORT: We report the case of a boy, 2.5 years of age, with subacute encephalopathic signs and symptoms and epileptic seizures followed by behaviour disorders, neurological regression, dyskinesias and insomnia. Results of a cerebrospinal fluid study were normal, the magnetic resonance scan of the head revealed a focal periventricular lesion and diffuse leptomeningeal uptake; moreover, the serial electroencephalograms showed high-amplitude delta activity interspersed with generalised intercritical epileptiform activity. The patient was given empirical treatment with high doses of corticoids and intravenous immunoglobulins with no response. After showing up positive for antibodies against the NMDA receptor, plasmapheresis was begun, which led to his swift and spectacular recovery. After more than 18 months' follow-up, his sequelae are limited to mild behavioural and language alterations. He has had no relapses and has not needed any kind of maintenance treatment. CONCLUSIONS: Anti-NMDA encephalitis is a treatable disorder and, sometimes, the first evidence of an underlying neoplasia, which makes its early recognition and treatment essential. Treatment of the non-paraneoplastic forms are based on immunotherapy: glucocorticoids, intravenous immunoglobulins, plasmapheresis and immunosuppressants. Plasmapheresis can bring about a fast, spectacular improvement.

Human epidermal growth factor receptor 2 overexpression in breast cancer of patients with anti-Yo--associated paraneoplastic cerebellar degeneration.

Isolated case reports suggest that breast tumors from patients with paraneoplastic cerebellar degeneration (PCD) and Yo antibodies overexpress human epidermal growth factor receptor 2 (HER2). HER2 overexpression is present in 15%-25% of breast cancers and is associated with poor prognosis. We retrospectively analyzed the status of HER2 in breast tumors of 27 patients with anti-Yo-associated PCD to evaluate whether HER2 overexpression in this group of patients is higher than expected. In addition, we analyzed HER2 status of 19 breast tumors from patients with paraneoplastic neurological syndromes and Ri antibodies to see whether HER2 was specifically related to anti-Yo-associated PCD. We also assessed cdr2 expression (the onconeural antigen recognized by Yo antibodies) in 21 HER2-positive breast tumors from patients without paraneoplastic neurological syndromes. HER2 was overexpressed in 26 patients (96.3%) with anti-Yo-associated PCD but only in 2 patients (10.5%) with paraneoplastic neurological syndromes associated with Ri antibodies (P< .0001). Only 5 (23.8%) of the 21 HER2-positive breast tumors showed cdr2 immunoreactivity. This study shows a very high frequency of HER2 overexpression in breast cancers in patients with anti-Yo-associated PCD but not in those from patients with Ri antibodies. Although the expression of cdr2 onconeural antigen is not high in HER2-positive breast cancers, HER2 overexpression seems to be an important requirement to develop an anti-Yo-associated PCD.

Prevalence and immunological spectrum of temporal lobe epilepsy with glutamic acid decarboxylase antibodies.

BACKGROUND AND PURPOSE: High levels of glutamic acid decarboxylase (GAD)-ab were initially described in patients with stiff person syndrome, and have since also been observed in patients with other neurological diseases. Temporal lobe epilepsy (TLE) seems to be specially associated. Our purpose is to describe the prevalence of GAD-ab in patients with TLE, and to characterize the clinical-immunological profile of TLE patients with high levels of GAD-ab. METHODS: An immunological profile including GAD-ab and antinuclear, anti-DNA, anti-cardiolipin, anti-transglutaminase and antithyroid antibodies was determined in a consecutive series of patients with TLE. As adulthood onset is the least common onset in TLE + hipocampal sclerosis and febrile seizures, we selected patients whose onset was after 30 years of age, to expand the spectrum of aetiologies. Patients were divided into two groups: known aetiology, 19 patients (45%) and unknown aetiology, 23 (55%). The clinical-immunological study included TLE patients with high GAD-ab levels (>1000 IU). RESULTS: Amongst 42 patients, serum GAD-ab levels were positive in 5 (152-11, 963 IU/ml), all from the unknown aetiology group. Thus, GAD-ab levels were positive in 21.7% and high in 8.7% of the unknown aetiology group. The immunological profile study included nine patients (seven pharmacoresistant), of whom six were women (66%) with mean age 41 years. Three patients reported acute debut, four (44%) insulin-dependent diabetes mellitus, five (55%) other concomitant autoimmune diseases, four (44%) memory impairment and four moderate-to-severe mood disturbance. Intrathecal synthesis of GAD-ab was observed in seven patients (77%). CONCLUSIONS: Temporal lobe epilepsy with GAD-ab is not a rare condition. In the subgroup of patients with high titres, this epilepsy is often pharmacoresistant and associated with memory impairment, depression and other autoimmune diseases.

White matter abnormalities in primary Sjögren syndrome.

OBJECTIVE: To describe the main characteristics of patients with primary Sjögren syndrome (SS) and white matter abnormalities (WMA) seen by a specialist SS unit. METHODS: The study cohort included 321 consecutive patients fulfilling the 2002 classification criteria for primary SS. We retrospectively analyzed the results of neuroimaging studies performed in patients who presented with neurological symptoms. Patients were further evaluated by three neurologists to determine fulfillment of the McDonald criteria for the diagnosis of multiple sclerosis (MS). RESULTS: Fifty-one (16%) patients had at least one neuroimaging study, and 25 of these had WMA. WMA were classified as vascular pathological changes in 21 patients: 10 had multiple small focal lesions, 7 had beginning confluence of lesions and 4 had diffuse involvement of the entire region. WMA were classified as inflammatory/demyelinating lesions (MS-like) in 4 patients who fulfilled the MRI Barkhof criteria. Patients with inflammatory/demyelinating lesions were younger (53.7 vs. 73.5 years, P = 0.001) and had a lower frequency of hypertension (25% vs. 86%, P = 0.031) and altered glomerular filtration rate (0% vs. 70%, P = 0.047) in comparison with patients with vascular lesions. The multivariate age-sex adjusted model including the seven variables which were statistically significant in the univariate analysis (antimalarial therapy, leukopenia, anti-La/SSB antibodies, diabetes, hypertension, metabolic syndrome and HDL-c levels) identified hypertension (P = 0.019) and HDL-c levels (P = 0.032) as independent predictors of WMA in primary SS patients. CONCLUSION: Neuroimaging studies disclosed WMA in 49% of patients with primary SS and suspected neurological involvement. WMA were identified as vascular pathological changes in 80% of the patients, and hypertension and HDL-c levels as predictive factors for this association.