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Gastrointestinal pseudo-obstruction (GIPO) is a phenotype of the paraneoplastic neurological syndrome (PNS). We herein report a case of small-cell lung carcinoma (SCLC) with GIPO elicited by an immune checkpoint inhibitor (ICI). A 75-year-old man with SCLC developed intractable intestinal obstruction after receiving one course of anticancer drugs (durvalumab, etoposide, and carboplatin). The serum anti-Hu antibody (Hu-Ab) was positive, and the patient was diagnosed with GIPO. Corticosteroid treatment did not improve the GIPO, and the patient died. There are few reports of GIPO after ICI treatment in patients with lung cancer, so a further investigation will be required to elucidate the mechanism by which ICIs elicit PNS. Checking for neuronal antibodies may help identify patients with SCLC who are at risk of developing PNS due to ICI treatment.

Background and Objectives: Dysautonomia has been associated with paraneoplastic neurological syndrome (PNS)-related mortality in anti-Hu PNS, but its frequency and spectrum remain ill-defined. We describe anti-Hu patients with dysautonomia, estimate its frequency, and compare them to patients without dysautonomia., Methods: Patients with anti-Hu antibodies diagnosed in the study centre (1990-2022) were retrospectively reviewed; those with autonomic signs and symptoms were identified., Results: Among 477 anti-Hu patients, 126 (26%) had dysautonomia (the only PNS manifestation in 7/126, 6%); gastrointestinal (82/126, 65%), cardiovascular (64/126, 51%), urogenital (24/126, 19%), pupillomotor/secretomotor (each, 11/126, 9%), and central hypoventilation (10/126, 8%). Patients with isolated CNS involvement less frequently had gastrointestinal dysautonomia than those with peripheral (alone or combined with CNS) involvement (7/23, 30% vs. 31/44, 70% vs. 37/52, 71%; P = 0.002); while more frequently central hypoventilation (7/23, 30% vs. 1/44, 2.3% vs. 2/52, 4%; P < 0.001) and/or cardiovascular alterations (18/23, 78% vs. 20/44, 45% vs. 26/52, 50%; P = 0.055). Median [95% CI] overall survival was not significantly different between patients with (37 [17; 91] months) or without dysautonomia (28 [22; 39] months; P = 0.78). Cardiovascular dysautonomia (HR: 1.57, 95% CI [1.05; 2.36]; P = 0.030) and central hypoventilation (HR: 3.51, 95% CI [1.54; 8.01]; P = 0.003) were associated with a higher risk of death, and secretomotor dysautonomia a lower risk (HR: 0.28, 95% CI [0.09; 0.89]; P = 0.032). Patients with cardiovascular dysautonomia dying ≤ 1 year from clinical onset had severe CNS (21/27, 78%), frequently brainstem (13/27, 48%), involvement., Discussion: Anti-Hu PNS dysautonomia is rarely isolated, frequently gastrointestinal, cardiovascular and urogenital. CNS dysfunction, particularly brainstem, associates with lethal cardiovascular alterations and central hypoventilation, while peripheral involvement preferentially associates with gastrointestinal or secretomotor dysautonomia, being the latest more indolent., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany.)

Rationale: Paraneoplastic neurological syndrome with anti-Hu antibody (Hu-PNS) is a neurological disorder that occur in patients with malignancy. The syndrome has a wide range of presentations and can present before diagnosis of primary malignancy. Familiarity with these paraneoplastic neurological syndromes can help early recognition and take appropriate regimens., Patients Concerns: Diagnosis and treatment of Hu-PNS., Diagnoses: This is retrospective study that analyzed the clinical data of this case. Through retrospective analysis and targeted antibody screening, serum anti-Hu antibody was detected. Subsequent spinal imaging revealed a mass in the paraspinal region, which was confirmed as ganglioneuroblastoma by pathologic examination., Interventions: The child was treated with a course of intravenous immunoglobulin and radical surgical operation without chemotherapy., Outcomes: The neurological symptoms were gradually improved and no signs indicate disease progression or tumor recurrence., Lessons: Hu-PNS has rarely been reported in children with ganglioneuroblastomas. They can mimic non-neoplastic processes, making detection and diagnosis difficult. Serum and/or cerebrospinal fluid onconeural antibody can strongly indicate occult cancers. Early detection of paraneoplastic neurological syndromes can help take appropriate regimens and improve prognosis., Competing Interests: The authors declare no conflicts of interest., (Copyright © 2024 the Author(s). Published by Wolters Kluwer Health, Inc.)

An 81-year-old woman was admitted to our hospital due to paresthesia of the extremities and difficulty in walking for three months. She underwent a total hysterectomy and bilateral salpingo-oophorectomy for large cell neuroendocrine carcinoma (LCNEC) of the endometrium seven months before the admission. The serum levels of neuron specific enolase (NSE) reduced after the surgery. She showed numbness of her limbs, disturbance of vibration, areflexia and autonomic dysfunction. Nerve conduction studies showed sensory dominant sensory neuronopathy. CT scan of her abdomen and pelvis revealed the recurrence of LCNEC of the endometrium. The serum levels of NSE was elevated and anti-Hu antibody was also positive. Other laboratory test, including autoantibodies were unremarkable. We diagnosed her as paraneoplastic sensory neuronopathy associated with postoperative recurrence of LCNEC of the endometrium. Here we show a clinical picture of anti-Hu positive paraneoplastic neurological syndrome with LCNEC of the endometrium.

We present an illustrative case of a 62-year-old woman with small cell lung cancer who developed progressive worsening of pre-existing anti-Hu antibody associated sensory neuronopathy after treatment with programmed cell death-1 (PD-1) inhibitor, nivolumab. We review the literature and identify 6 reported cases to understand the clinical outcomes of patients with anti-Hu paraneoplastic neurologic syndrome (PNS) treated with anti-PD-1 treatment. The PNS clinical spectrum comprised of encephalitis, a combination of sensory neuronopathy and anti-NMDAR encephalitis, isolated sensory neuronopathy, and encephalomyelitis. Immune checkpoint inhibitor have the potential to worsen pre-existing anti-Hu PNS and may promote the development of anti-Hu PNS., Competing Interests: Declaration of Competing interest PR- The author declares that she has no competing interests. DH- The author declares that she has no competing interests. KG- The author serves on advisory boards for Sanofi Genzyme and Eli Lilly. JS- The author declares that she has no competing interests., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Background: Paraneoplastic neurological syndromes (PNS) are a group of syndromes that affect the central and peripheral neuromuscular system in association with cancer. Specific antibodies may assist in the diagnosis of PNS. The antibodies tested can be classified into those directed against intracellular neuronal proteins ("well characterized" PNS: Hu, Yo, RI, CV2, amphiphysin, Ma1, Ma2) and those directed against neural surface antigens (autoimmune encephalitis syndromes: NMDA, AMPA, LGI1, CASPR2, GABAR). We aimed to characterize patients with unexplained neuropsychiatric symptoms, in whom positive PNS antibodies were detected in the Sheba medical center, a large referral hospital., Methods: Clinical and demographic data of patients with positive PNS antibodies were collected during the years 2002-2016. Antibodies were tested by either Line immunoassay or by cell-based indirect immunofluorscent assay., Results: During the follow up of 14 years, 4010 PNS tests were performed in patients with unexplained neuropsychiatric symptoms. Seventy-two were found to be positive; among them we had full clinical data access to 44. The most frequent antibodies were anti-Hu (31.8%), anti-Yo (18.2%), anti-CV2 (13.6%), and anti-NMDA (9.1%), and the most common cancers were small-cell lung (SCLC) and ovarian cancers. In the well characterized paraneoplastic group, cancer was diagnosed in 55.9% of the patients, and in the autoimmune encephalitis group, 40.0% were diagnosed with cancer. A positive correlation between antibody titer and the presence of cancer was found. Ninety percent of the tests in patients who were found positive were ordered by a neurologist or neuro-oncologist., Conclusions: The titers of PNS auto-antibodies can predict cancer in patients whom anti-PNS antibodies are tested. In addition, consultation with a specialist should be considered before this test is ordered., (Copyright © 2018 Elsevier Inc. All rights reserved.)

The case is a 75-year-old female. She had dysesthesia in the distal extremities and truncal ataxia, and they had progressed in two months. Neurological examination revealed the findings of segmental dysesthesia in the distal extremities, impaired deep sensations in the trunk and four limbs, and painful legs and moving toes (PLMT). After workup, she was diagnosed with small cell lung cancer and her blood sample was positive for anti-Hu antibody. We concluded that her neurological symptoms were attributable to sensory neuronopathy associated with paraneoplastic syndrome. No cases with PLMT caused by paraneoplastic syndrome have been reported so far. She had chemotherapy to lung cancer and Duloxetine without improvement of PLMT. On the other hand, intravenous immunoglobulin treatment improved lightening pain in the toes without improvement of moving toes.

To describe and analyze the clinical features and prognosis of patients with anti-Hu associated paraneoplastic neurological syndromes (PNS).The symptoms, MRI findings, cerebrospinal fluid (CSF) changes, electroencephalogram (EEG) characteristics and prognoses of 9 well-diagnosed anti-Hu associated PNS patients were analyzed.The study enrolled 6 female and 3 male patients. Three patients presented with vertigo and 6 patients exhibited a depressed mood, numbness of the lower limbs, generalized pains, seizures, mental disturbances, and a temporary unilateral hand tremor on initial presentation. Three patients presented with MRI abnormalities localized in the mesial temporal lobe and the thalamus. Abnormal interictal EEG readings were observed in all 5 patients who underwent EEG study. Four patients were found lung cancer (3 during hospitalization, 1 during follow-up). Seven patients were treated with immunotherapy and improved in symptoms. Three patients died during follow-up (2 with lung cancer).The clinical manifestation of anti-Hu associated PNS is diverse and multifocal. EEG may be more sensitive than MRI for early diagnosis of PNS. Long-term follow-up for patients with CT-negative anti-Hu associated PNS is necessary.

Paraneoplastic limbic encephalitis (PLE) is a rare autoimmune neurological syndrome observed in lung cancer patients. We retrospectively investigated the clinical characteristics, treatment responses, and prognoses in 16 PLE patients who were subsequently diagnosed with lung cancer. Fifteen patients initially presented with disturbance of consciousness, 13 with disorientation, and 12 with seizures. Thirteen patients had autoantibodies, including eight with gamma aminobutyric acid B receptor (GABA B R) antibodies and eight with Hu antibodies. PET-CT revealed lung neoplasms in 13 patients, nine of whom exhibited abnormal metabolic activity in the temporal lobe and hippocampus. Fifteen cases were confirmed as limited-stage small cell lung cancer and one as stage IV large cell neuroendocrine carcinoma. Eleven patients received immunomodulatory therapy, and four showed neurological improvement, who all had antibodies against GABA B R. Fifteen patients received chemotherapy, of which 14 maintained or improved their PLE status. The overall cancer response rate was 75%, and two-year overall survival was 74.7%. Our results suggest patients with GABA B encephalitis might respond better to immunotherapy than the classical PLE patients with anti-Hu antibodies. Anti-cancer treatment could further improve neurological symptoms. Lung cancer patients with PLE, especially those in limited stage, might have better outcome due to earlier diagnosis and prompt anti-cancer treatment.

Paraneoplastic neurological syndromes (PNS) are caused by immune responses against neuronal antigens expressed by the tumor. Based on the immunological pathomechanisms and responsiveness of treatments, onconeuronal antibodies are divided into two categories: 1) antibodies against neural intracellular antigens and 2) antibodies against neuronal surface or synaptic antigens. The recent discovery of onconeuronal antibodies have radically changed concepts of CNS autoimmunity, including PNS. The recognition of PNS provides a foundation for the early detection of underlying tumors and initiations of prompt treatments, which can result in substantial improvement. We here review the characteristic onconeuronal antibodies, including anti-Hu, anti-Ma2, and anti-N-methyl-D-aspartate receptor, and discuss the algorithm for the diagnosis of PNS.

Rationale: Paraneoplastic syndrome is a very rare syndrome among prostate cancer patients. In particular, paraneoplastic sensorimotor neuropathy has never been reported as a complication of prostatic adenocarcinoma., Patient Concerns: A 75-year-old man who was diagnosed with prostatic adenocarcinoma with multiple metastases received cancer treatment. But, numbness and tingling sensations in both sides of the upper and lower limbs got progressively worse., Diagnosese: He was diagnosed with positive anti-Hu antibodies paraneoplastic sensorimotor polyneuropathy caused by prostatic adenocarcinoma., Interventions: The patient received physical therapy, occupational therapy, and opioid medication during 3 weeks at cancer rehabilitation department during 3 weeks., Outcomes: There was no improvement in functional outcome in this patient. But, the patient's neuropathic pain was improved by the use of opioid agents., Lessons: This case report is the first to report anti-Hu antibody-positive paraneoplastic sensorimotor neuropathy in a patient with adenocarcinoma of the prostate.

Introduction: Indications for autoantibody testing in patients with rapid-onset cognitive impairment have expanded in step with the growing number of disease-associated autoantibodies and clinical syndromes. Although increased access to autoantibody testing has broadened our understanding of the spectrum of autoimmune encephalitis (AE), it has also produced new challenges associated with deciphering the contributions of disease-associated autoantibodies in patients with atypical clinical features and/or multiple autoantibodies. These challenges are illustrated through presentation of a patient with AE associated with autoantibodies against intracellular and cell-surface neuronal antigens. The implications of detection of multiple autoantibodies are considered in the context of relevant literature, and used to frame a diagnostic and therapeutic approach., Case Report: A previously well 67-year-old man presented with encephalopathy and psychosis, impaired visual fixation, and ataxia, emerging over 3 months. Hu, CRMP-5, and NMDAR autoantibodies were identified in the cerebrospinal fluid. No malignancy was discovered despite extensive investigations. An aggressive course of immunotherapy temporarily stabilized his course; however, the patient succumbed to his illness 10 months after symptom onset. Lack of sustained response to immunotherapy and neuropathologic findings suggested that AE associated with Hu antibodies was primarily responsible for this patient's progressive decline., Conclusions: Multiple autoantibodies may be detected in patients with AE. When antibodies targeting intracellular and cell-surface antigens are detected together, investigation and treatment of syndromes associated with intracellular antibodies should be prioritized, acknowledging the link between these antibodies and irreversible neuronal injury. In paraneoplastic cases, prognosis may be tied to early detection and treatment of the underlying malignancy.

Autoimmune encephalitis is an uncommon complication of immune checkpoint inhibitor therapy. This article reports a case of fatal anti-Hu-associated autoimmune limbic encephalitis presenting within 8 weeks following anti-PD1 therapy in a patient with myxoid chondrosarcoma and pre-existing anti-Hu antibodies. Although tumor reduction occurred in response to PD-1 inhibitor therapy, the patient had a rapidly progressive decline in neurologic function despite initial stabilization with immunosuppression. Considering the increasing use of immune checkpoint inhibitors for the treatment of various malignancies, an increase in the occurrence of neurologic adverse events is likely, requiring prompt intervention and enhanced pharmacovigilance in malignancies associated with onconeuronal antibodies., Competing Interests: Disclosures of potential conflicts of interest may be found at the end of this article., (© AlphaMed Press 2017.)

A 58-year-old man was being treated for squamous non-small-cell lung cancer with nivolumab. At the 17th of biweekly administrations he presented with global dysphasia, dysarthria and myoclonus in the right upper extremity. MRI showed multiple T2/FLAIR hyperintense lesions in the left hemisphere; lumbar puncture showed lymphocytic pleiocytosis in the CSF without identifiable pathogens. Hu antibodies were present in serum and CSF. Nivolumab was discontinued and corticosteroids were administered. The neurological symptoms gradually improved; MRI showed complete remission of cerebral lesions. After rechallenge with nivolumab his symptoms and cerebral lesions recurred, proving the causal relationship with nivolumab. After tapering of corticosteroids, a second relapse occurred., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Acute confusion is a common symptom of physical illness in the older patient. In the majority, it is transient and resolves on treatment of precipitants. In a subset of patients, however, neurological decline is progressive, raising concern about a serious underlying cause. We describe the case of a 71-year-old woman who developed progressive cognitive impairment following insertion of a permanent pacemaker for sinoatrial arrests. An initial diagnosis of delirium secondary to a urinary tract infection was suspected; however, the patient became increasingly confused despite treatment. Laboratory tests revealed serum anti-Hu paraneoplastic antibodies, and CT chest identified an occult lung tumour. Cervical lymph node histopathology confirmed a diagnosis of small cell carcinoma of the lung. Although a rare cause of confusion, paraneoplastic encephalomyelitis should be recognised early to allow timely identification and treatment of the associated cancer., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Ltd (unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.)

Therapeutic apheresis has emerged as a major treatment option for autoantibody-associated inflammatory diseases of the nervous system. This includes patients with autoimmune encephalitides caused by antibodies against neuronal proteins. Plasma exchange (PE) and immunoadsorption (IA) constitute two possibilities to eliminate pathogenic antibodies from patients' plasma, but their efficacy and safety has not been prospectively assessed in larger patient groups of autoimmune encephalitides. In a prospective observational case control study, we, therefore, investigated the disease courses and treatment effects of 21 patients with autoimmune encephalitis associated with NMDAR, LGI1, CASPR2, GAD, mGluR5 and Hu antibodies. Patients were randomly assigned to receive PE (n = 11) or IA (n = 10). Symptoms were evaluated using the modified Rankin Scale (mRS). Side effects or adverse events were recorded. Both interventions, IA (p = 0.014) and PE (p = 0.01), resulted in significant reduction of the median mRS. With IA, 60 % of the patients improved clinically by at least 1 mRS score, none worsened. PE led to a comparable symptom reduction in 67 % of the cases. During 83 PE sessions, three adverse events were documented, while no side effects occurred under IA. Symptom improvement was significantly associated with younger age (r = -0.58), but not with disease duration. Therapeutic apheresis was most effective for neuronal surface antigens (83.3 %), followed by intracellular-synaptic antigens (66.7 %). Both IA and PE resulted in moderate to marked clinical improvement, with a low rate of adverse events. Apheresis is well tolerated and effective also as first-line therapy in autoimmune encephalitis, particularly in patients with antibodies targeting neuronal surfaces.

This article reports the case of a 68-year-old patient with anti-HU antibodies paraneoplastic encephalitis. The clinical manifestations were atypical and the paraclinical work-up, notably the magnetic resonance imaging (MRI) showing bilateral posterior thalamic hyperintensities (pulvinar sign), misleadingly pointed towards a variant Creutzfeld-Jakob disease. After presenting the case, the differential diagnosis of the pulvinar sign is discussed along with other important diagnostic considerations., (© The Author(s) 2016.)

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.

Objective: There is still no consensus about whether to perform PET/CT to detect carcinoma in paraneoplastic neurological syndromes (PNS) in patients with or without antibodies. The aim of this study is to determine the diagnostic accuracy of PET/CT and antibodies in patients with PNS., Material and Methods: A retrospective study was conducted on patients with clinically suspected PNS between 2008 and 2013. The association between histopathological findings, paraneoplastic antibodies, and PET/CT findings were evaluated. Sensitivity and specificity for the detection of underlying malignancy were calculated for PET/CT and paraneoplastic antibodies., Results: A total of 42 patients were analyzed. Of these 42 patients, 32 (75%) had a classical PNS, 6 (14%) had positive PET/CT findings, and 34 were tested for the presence of antibodies (anti-Hu Ab, anti-Yo Ab, and anti-Ri Ab). Twenty one of 34 patients had positive antibodies. Of the 6 patients with positive PET/CT findings, 6 had positive histopathological results. Among 21 patients with positive biomarkers, carcinoma was confirmed only in 5 patients. One patient with negative antibodies, but positive PET/CT findings, was diagnosed with a tumor. Gastric carcinoma was detected in 1 patient with negative PET/CT findings and antibodies during follow-up. Based on the results, PET/CT was found to have 85.71% sensitivity, 100% specificity, 100% positive and 97.22% negative predictive values in the detection of tumors., Conclusion: PET/CT has a certain diagnostic accuracy for detecting underlying malignancy in patients with PNS, regardless of the presence of paraneoplastic antibodies., (Copyright © 2015 Elsevier España, S.L.U. and SEMNIM. All rights reserved.)

Autoimmune dementia and encephalopathies (ADE) are complex disorders that can cause immune-mediated cognitive deficits and have confusing nomenclature. Presentation varies from acute limbic encephalitis to subacute or chronic disorders of cognition mimicking neurodegenerative dementia. It may occur as a paraneoplastic phenomenon or an idiopathic autoimmune phenomenon. The presence of a personal/family history of autoimmunity, inflammatory spinal fluid, serologic evidence of autoimmunity (neural or nonorgan-specific), or mesial temporal magnetic resonance imaging abnormalities are clues to diagnosis. Bedside cognitive assessment and/or detailed neuropsychologic testing are useful. Neural-specific autoantibodies, mostly discovered in the past two decades, may bind antigens on the cell surface (e.g., N-methyl-d-aspartate receptor autoantibodies) and are likely to be pathogenic, with treatment aimed at antibody-depleting agents often with success, while antibodies binding intracellular antigens (e.g., antineuronal nuclear autoantibody type 1 (ANNA1 or anti-Hu)) are a marker of a T-cell-mediated process and treated with T-cell-depleting immunotherapies, with variable responses. Detection and treatment of cancer (when present) are essential. High-dose corticosteroids are the initial treatment in most patients and may serve as a diagnostic test when the diagnosis is uncertain. Repeat cognitive testing after immunotherapy helps document objective improvements. Maintenance immunotherapy is recommended in those at risk for relapse. Prognosis is variable, but paraneoplastic ADE with antibodies to intracellular antigens have a worse prognosis. The field is still developing and future studies should provide guidelines for diagnosis and treatments., (© 2016 Elsevier B.V. All rights reserved.)

Autoimmune autonomic disorders occur because of an immune response directed against sympathetic, parasympathetic, and enteric ganglia, autonomic nerves, or central autonomic pathways. In general, peripheral autoimmune disorders manifest with either generalized or restricted autonomic failure, whereas central autoimmune disorders manifest primarily with autonomic hyperactivity. Some autonomic disorders are generalized, and others are limited in their anatomic extent, e.g., isolated gastrointestinal dysmotility. Historically, these disorders were poorly recognized, and thought to be neurodegenerative. Over the last 20 years a number of autoantibody biomarkers have been discovered that have enabled the identification of certain patients as having an autoimmune basis for either autonomic failure or hyperactivity. Peripheral autoimmune autonomic disorders include autoimmune autonomic ganglionopathy (AAG), paraneoplastic autonomic neuropathy, and acute autonomic and sensory neuropathy. AAG manifests with acute or subacute onset of generalized or selective autonomic failure. Antibody targeting the α3 subunit of the ganglionic-type nicotinic acetylcholine receptor (α3gAChR) is detected in approximately 50% of cases of AAG. Some other disorders are characterized immunologically by paraneoplastic antibodies with a high positive predictive value for cancer, such as antineuronal nuclear antibody, type 1 (ANNA-1: anti-Hu); others still are seronegative. Recognition of an autoimmune basis for autonomic disorders is important, as their manifestations are disabling, may reflect an underlying neoplasm, and have the potential to improve with a combination of symptomatic and immune therapies., (© 2016 Elsevier B.V. All rights reserved.)

Tonsillar metastatic small cell lung cancer (SCLC) is rare, while anti-Hu antibodies are frequently found in SCLC. A 66-year-old man was admitted to our hospital with painful dysesthesia and muscle weakness in the distal extremities for over 1 year, progressive dysphagia for over 1 month, and severe cough and dyspnea for over 1 week. He was diagnosed with SCLC accompanied by tonsillar metastasis and anti-Hu antibody-associated paraneoplastic sensory neuropathy (PSN). The patient tolerated 6 cycles of sequential chemoradiotherapy and gradually recovered. The patient's disease remained in remission 2 years after the diagnosis with a remarkable reduction of tumor burden and a persisting high titer of anti-Hu antibodies. To our knowledge, this is the first case of tonsillar metastatic SCLC accompanied by anti-Hu antibody-associated PSN, whereby the anticancer immune response was presumed to play a vital role in disease control. Unilateral tonsillar metastasis of SCLC accompanied by anti-Hu antibody-associated PSN can occur and in certain circumstances, may have a favorable prognosis., Competing Interests: The authors have no conflicts of interest to disclose.

The anti-Hu antibody is one of the most famous onco-neural antibodies related to paraneoplastic neurological syndrome, and is associated with small cell lung carcinoma in most cases. Here, we report a case of poorly differentiated hepatocellular carcinoma accompanied by paraneoplastic peripheral neuropathy positive for the anti-Hu antibody. Image inspection before operation revealed that no tumors were found in organs other than the liver, including lung, and that the liver tumor had no metastatic lesion. The liver tumor showed histological appearance of poorly differentiated carcinoma with cartilaginous metaplasia and partial blastoid cell appearance. Most tumor cells presented trabecular-like structure lined by sinusoidal vessels. Immunohistochemically, the tumor cells were positive for low molecular weight cytokeratin and vimentin, partially positive for cytokeratin 19 and CD56, but negative for synaptophysin, chromogranin A and alpha-fetoprotein. Based on the trabecular-like morphology and the results of immunohistochemical staining, we concluded that the tumor was diagnosed as poorly differentiated hepatocellular carcinoma. Anti-Hu antibody-positive paraneoplastic peripheral neuropathy accompanied with liver tumor is extremely rare as far as is known. The presented case indicates that poorly differentiated carcinoma has the potential to be the responsible lesion of anti-Hu antibody-positive paraneoplastic neurological syndrome and systemic work-up is important for the management of this neurological disorder., (© 2015 Japanese Society of Pathology and Wiley Publishing Asia Pty Ltd.)

Introduction: Small cell lung cancer (SCLC), having properties of neuroendocrine cells, accounts for a small (15 percent) but significant percent of all newly diagnosed lung cancers and is distinguished from non-small cell lung cancer by its rapid doubling time, high growth fraction and the early development of widespread metastases. Therefore, investigation into early diagnosis and treatment is crucial. One sequela of SCLC is a paraneoplastic neurological syndrome usually mediated by a high titer of anti-Hu antibodies, a disease which can present in several variations of paraneoplastic encephalomyelitis. The presence of anti-Hu antibodies in patient serum, even at a low titer, may serve as a diagnostic marker for SCLC and as a model for antibody-based early cancer detection. Furthermore, anti-Hu titers may eventually function as a prognostic indicator and trending titers may be a way to monitor treatment of SCLC and associated paraneoplastic syndromes., Methods: In this retrospective chart review from a single hospital, we review all patients who had positive anti-Hu antibodies and discuss level of titers at diagnosis, outcomes, and length of survival., Results: We describe three cases of positive anti-Hu antibodies and document their diagnosis of SCLC and outcomes., Conclusions: Anti-Hu antibodies can be used as a diagnostic tool for aiding in the diagnosis of SCLC. Anti-Hu antibodies may be able to be followed as a marker of progression of the disease.

Objectives: Paraneoplastic neurological syndromes (PNSs) are rare disorders in association with cancer and sub-divided into "classical" and "non-classical" syndromes according to a 2004 consensus paper proposed by a panel of PNS experts. "Classical" PNSs are regarded to account for the vast majority of cases. However, systematic reports on clinical PNS manifestations are rare. Therefore, we analyzed the spectrum of PNS in our clinic., Methods: We retrospectively investigated medical records from consecutive patients diagnosed with definite PNS and serological evidence of well-characterized onconeural antibodies (anti-Hu, Yo, Ri, CV2/CRMP5, Ma1, Ma2, and amphiphysin) analyzed between 1991 and 2014 in our clinic., Results: Of the 50 patients identified with onconeural antibody-positive PNS, 28 patients (56.0%) had "classical" PNS, and 22 (44.0%) "non-classical" PNS. Subacute cerebellar degeneration was the most frequent "classical" syndrome, brainstem encephalitis and subacute sensorimotor neuronopathy the most frequent "non-classical" syndromes. Anti-Hu antibodies were most frequent in both groups. 86.1% of patients developed neurological symptoms before the cancer was known. No differences between "classical" and "non-classical" syndromes were detected with respect to age, tumor entities and median time to diagnosis. However, whereas most patients with "classical" syndromes were females, there was no gender predominance in patients with "non-classical" PNS and the latter had significantly more frequent peripheral neurological syndromes., Conclusions: The so-called "non-classical" PNSs in association with well-characterized onconeural antibodies were more common in our patient population than expected. Therefore, in neurological disorders of unclear etiology with a subacute onset and atypical presentation further diagnostic work-up including investigation of onconeural antibodies is necessary., (Copyright © 2015 Elsevier B.V. All rights reserved.)

Secretion of type I interferon (IFN) is the first cellular reaction to invading pathogens. Despite the protective function of these cytokines, an excessive response to their action can contribute to serious pathologies, such as autoimmune diseases. Transcripts of most cytokines contain adenylate-uridylate (A/U)-rich elements (AREs) that make them highly unstable. RNA-binding proteins (RBPs) are mediators of the regulatory mechanisms that determine the fate of mRNAs containing AREs. Here, we applied an affinity proteomic approach and identified lethal, abnormal vision, drosophila-like 1 (ELAVL1)/Hu antigen R (HuR) as the predominant RBP of the IFN-β mRNA ARE. Reduced expression or chemical inhibition of HuR severely hampered the type I IFN response in various cell lines and fibroblast-like synoviocytes isolated from joints of rheumatoid arthritis patients. These results define a role for HuR as a potent modulator of the type I IFN response. Taken together, HuR could be used as therapeutic target for diseases where type I IFN production is exaggerated., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The expression of interferon (IFN) β is highly induced in immune and nonimmune cells in response to virus infection. This upregulation is mediated at both transcriptional and posttranscriptional levels. Whereas the signaling pathways triggered by innate virus receptors leading to transcription factor activation have been extensively studied, the mechanisms by which IFN-β mRNA stability is posttranscriptionally controlled are not fully understood. In this issue of the European Journal of Immunology, Herdy et al. [Eur. J. Immunol. 2015 45:1500-1511] show that a human RNA-binding protein, embryonic lethal, abnormal vision, drosophila-like 1 (ELAVL1)/Hu antigen R (HuR), strongly associates with IFN-β mRNA via AU-rich sequences present in its 3' untranslated region in various human cell lines. The authors show that ELAVL1/HuR is required for the stabilization of IFN-β mRNA, and suppression of ELAVL1/HuR by its inhibitor MS-444 leads to impaired expression of IFN-β in response to viral dsRNA treatment. Thus, this study uncovers a novel mechanism of posttranscriptional IFN-β mRNA regulation in response to virus infection, through IFN-β stabilization by ELAVL1/HuR. Future studies are expected to identify further regulatory mechanisms of IFN-β stabilization and destabilization in the course of antiviral responses., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Post-transcriptional regulation of mRNA by the RNA-binding protein HuR (encoded by Elavl1) is required in B cells for the germinal center reaction and for the production of class-switched antibodies in response to thymus-independent antigens. Transcriptome-wide examination of RNA isoforms and their abundance and translation in HuR-deficient B cells, together with direct measurements of HuR-RNA interactions, revealed that HuR-dependent splicing of mRNA affected hundreds of transcripts, including that encoding dihydrolipoamide S-succinyltransferase (Dlst), a subunit of the 2-oxoglutarate dehydrogenase (α-KGDH) complex. In the absence of HuR, defective mitochondrial metabolism resulted in large amounts of reactive oxygen species and B cell death. Our study shows how post-transcriptional processes control the balance of energy metabolism required for the proliferation and differentiation of B cells.

Previous studies have suggested that common antigens that exist in neurons and tumor cells trigger cross immunoreaction, which attacks the neurons and tumor cells simultaneously. This action leads to paraneoplastic symptoms and slowed tumor growth. The present study co‑cultured peripheral blood mononuclear cells (PBMCs) from anti‑Hu antibody‑associated patients with paraneoplastic neurological syndrome (PNS) and the small cell lung cancer cell line NCI‑H446 (H446) in vitro. In the PNS group, no significant difference was observed in the proliferation index of PBMCs and H446 cells between the mixed or separate cultures. The proportion of CD4+ T cells in patients with PNS (76.54±3.96%) was significantly higher (P<0.05) compared with the healthy control individuals (51.75±17.3%). In conclusion, the sensitized specific T cells in the PBMCs of PNS patients predominantly comprised of CD4+ T cells, which had no inhibitory effect on small cell lung cancer cells in vitro.

A 64-year-old Japanese woman presented with a three-month history of progressive numbness and weakness of the lower extremities. A neurological examination and nerve conduction study indicated sensorimotor polyneuropathy. Since the serum anti-Hu antibody titer was remarkably elevated, paraneoplastic neurological syndrome was highly suspected. A thoracoscopic biopsy of the hilar lymph nodes, in which (18)F-fluorodeoxyglucose uptake was obviously increased, revealed pathological findings for small-cell lung cancer (SCLC). Subsequently, the patient presented with generalized tonic-clonic seizures, and cerebral MRI showed reversible multifocal brain lesions, considered to reflect paraneoplastic encephalopathy. After two courses of chemotherapy for SCLC, the brain lesions totally disappeared.

A 69-year-old man experienced general malaise, weight loss, amnesia, gait disturbance, and restlessness a month prior to admission. Brain MRI showed high intensity areas in the bilateral medial temporal lobes and insular cortices on FLAIR images, and therefore, he was diagnosed with limbic encephalitis. After admission, quadriplegia and respiratory failure progressed rapidly, and he needed ventilatory management. A nerve conduction study revealed low compound muscle action potential amplitude with loss of sensory nerve action potential, which indicated axonal sensorimotor neuropathy. We administered intravenous immunoglobulin and methylprednisolone pulse therapy, but he did not recover. Although no tumor was found on CT, his serum was positive for anti-Hu antibody; therefore, we diagnosed him with paraneoplastic neurological syndrome. An FDG-PET study showed accumulation at lesions on two hilar lymph nodes. Small cell lung carcinoma was detected by endobronchial ultrasound-guided transbronchial needle aspiration. Although paraneoplastic acute sensorimotor neuropathy with respiratory failure resembling Guillain-Barré syndrome is rare, identification of antibodies and servey of tumors aids accurate diagnosis.

Background: Several lines of evidence suggest a T cell-mediated immune response in paraneoplastic neurological syndromes with anti-Hu antibodies (Hu-PNS). In order to investigate whether suppression of T cell-mediated immune responses in Hu-PNS patients improved their neurological outcome, we performed a prospective open-label, single-arm study on sirolimus., Methods: Seventeen progressive Hu-PNS patients were treated with sirolimus with an intended treatment duration of 8 weeks. Primary outcome measures were (i) functional improvement, defined as a decrease of one or more points on the modified Rankin Scale (mRS), and (ii) improvement of neurological impairment, defined as an increase of one or more points on the Edinburgh Functional Impairment Tests (EFIT)., Results: One patient showed improvement on both clinical scales (mRS and EFIT). This patient presented with limbic encephalitis and improved dramatically from an mRS score of 3 to mRS 1. Another patient, with subacute sensory neuronopathy, remained stable at mRS 2 and improved one point on the EFIT scale. The other patients showed no improvement on the primary outcome measures. Median survival was 21 months., Conclusion: We conclude that treatment of Hu-PNS patients with sirolimus may improve or stabilize their functional disabilities and neurological impairments. However, the effects of this T cell-targeted therapy were not better than reported in trials on other immunotherapies for Hu-PNS. Trial Registration https://www.clinicaltrialsregister.eu/ctr-search/trial/2008-000793-20/NL., (© The Author(s) 2014. Published by Oxford University Press on behalf of the Society for Neuro-Oncology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Background: Most patients with small cell lung cancer (SCLC) or neuroblastoma (NB) already show clinically detectable metastases at diagnosis and have an extremely poor prognosis even when treated with combined modalities. The HuD-antigen is a neuronal RNA-binding protein that is expressed in 100% of SCLC tumor cells and over 50% of neuroblastoma cells. The correlation between high titers of circulating anti-HuD antibodies in patients and spontaneous tumor remission suggests that the HuD-antigen might be a potential molecular target for immunotherapy., Methods: We have constructed a new antibody-toxin compound (called BW-2) by assembling a mouse anti-human-HuD monoclonal antibody onto streptavidin/saporin complexes., Results: We found that the immunotoxin BW-2 specifically killed HuD-positive human SCLC and NB cancer cells at very low concentrations in vitro. Moreover, intratumoral immunotoxin therapy in a nude mouse model of human SCLC (n = 6) significantly reduced local tumor progression without causing toxicity. When the same intratumoral immunotoxin protocol was applied to an immunocompetent A/J mouse model of NB, significant inhibition of local tumor growth was also observed. In neuroblastoma allografted A/J mice (n = 5) treated twice with intratumoral immunotoxin, significant tumor regression occurred in over 80% of the animals and their duration of tumor response was significantly prolonged., Conclusions: Our study suggests that anti-HuD based immunotoxin therapy may prove to be an effective alternative treatment for patients with SCLC and NB.

Cancer-associated retinopathy (CAR) is one of the paraneoplastic neurological syndromes and characterised by retinal degeneration. Autoimmunity between cancer cells and retinal proteins is considered a major cause of CAR. The presence of serum autoantibodies to retinal antigens plays an important role in the diagnosis. A 60-year-old man reporting of visual disturbance and paresthaesia of extremities presented to our hospital. CT scan revealed a massive tumour in the left lower lobe of the lung. Small cell lung cancer was diagnosed histologically with bronchoscopy. Ophthalmological examination showed retinopathy but not optic neuritis. Anti-CV2/collapsin response mediator protein (CRMP)-5 and anti-Hu antibodies were detected by further serum examination. It has been reported that anti-CV2/CRMP5 antibodies are present in patients with neoplasms accompanied by retinopathy as well as optic neuritis. This is the first case of CAR with presence of anti-CV2/CRMP5 antibodies without neuritis., (2014 BMJ Publishing Group Ltd.)

Introduction: Paraneoplastic syndromes are a rare cancer complication with a frequent subacute evolution., Observation: A 62-year-old man was admitted presenting with a cerebellar syndrome and orthostatic hypotension with dysautonomia. Anti-Hu antibody research was positive. A subcarinal adenopathy biopsy found out a small cell lung carcinoma. Despite a treatment with immunoglobulin and chemotherapy, the patient died suddenly, after a raise of dysautonomia symptoms., Conclusion: Sudden death observations represent exceptional complications of paraneoplastic syndrome. They might be secondary to arrhythmias, ictal asystol or laryngospasm. Systematic research of paroxystic heart arrhythmias with holter-ECG in paraneoplastic syndrome may prevent sudden deaths., (Copyright © 2014 Société nationale française de médecine interne (SNFMI). Published by Elsevier SAS. All rights reserved.)

We describe a case of cerebellar ataxia associated with anti-Hu antibodies and benign ganglioneuroma. A 28-year-old woman developed progressive ataxia with hyporeflexia at the age of 19. Brain MRI showed progressive cerebellar atrophy. Neurophysiological studies, screening of immune-mediated ataxias, oncological markers, vitamin E and genetic tests for spinocerebellar ataxia types 1,2,3, Friedreich ataxia and POLG1 were negative. Anti-Hu antibodies were positive in Western blot and indirect immunofluorescence (1:640). Total-body computed tomography revealed a mediastinum mass; the histological diagnosis was maturing ganglioneuroma. Immunohistochemistry showed a mild reaction between the tumor and the patient's serum, and no reaction between the tumor and control serum. After surgery, serum anti-Hu titer decreased, while ataxic symptoms initially worsened and then stabilized. Ganglioneuroma is a benign tumor, usually derived from the maturation of a neuroblastoma. The benign histology and the presence of anti-Hu antibodies could be related to the positive oncological prognosis and to the slow clinical course mimicking a degenerative ataxia.

Antibodies directed to intracellular neural antigens have been mainly described in paraneoplastic peripheral neuropathies and mostly includes anti-Hu and anti-CV2/CRMP5 antibodies. These antibodies occur with different patterns of neuropathy. With anti-Hu antibody, the most frequent manifestation is sensory neuronopathy with frequent autonomic involvement. With anti-CV2/CRMP5 the neuropathy is more frequently sensory and motor with an axonal or mixed demyelinating and axonal electrophysiological pattern. The clinical pattern of these neuropathies is in keeping with the cellular distribution of HuD and CRMP5 in the peripheral nervous system. Although present in high titer, these antibodies are probably not directly responsible for the neuropathy. Pathological and experimental studies indicate that cytotoxic T-cells are probably the main effectors of the immune response. These disorders contrast with those in which antibodies recognize a cell surface antigen and are probably responsible for the disease. The neuronal cell death and axonal degeneration which result from T-cell mediated immunity explains why treating these disorders remains challenging., (Copyright © 2014 Elsevier Masson SAS. All rights reserved.)

Background: Anti-Hu and anti-Ri antibodies are paraneoplastic immunoglobulin (Ig)G autoantibodies which recognize cytoplasmic and nuclear antigens present in all neurons. Although both antibodies produce similar immunohistological labeling, they recognize different neuronal proteins. Both antibodies are associated with syndromes of central nervous system dysfunction. However, the neurological deficits associated with anti-Hu antibody are associated with neuronal death and are usually irreversible, whereas neurological deficits in patients with anti-Ri antibody may diminish following tumor removal or immunosuppression., Methods: To study the effect of anti-Hu and anti-Ri antibodies on neurons, we incubated rat hippocampal and cerebellar slice cultures with anti-Hu or anti-Ri sera from multiple patients. Cultures were evaluated in real time for neuronal antibody uptake and during prolonged incubation for neuronal death. To test the specificity of anti-Hu antibody cytotoxic effect, anti-Hu serum IgG was incubated with rat brain slice cultures prior to and after adsorption with its target Hu antigen, HuD., Results: We demonstrated that: 1) both anti-Hu and anti-Ri antibodies were rapidly taken up by neurons throughout both cerebellum and hippocampus; 2) antibody uptake occurred in living neurons and was not an artifact of antibody diffusion into dead cells; 3) intracellular binding of anti-Hu antibody produced neuronal cell death, whereas uptake of anti-Ri antibody did not affect cell viability during the period of study; and 4) adsorption of anti-Hu antisera against HuD greatly reduced intraneuronal IgG accumulation and abolished cytotoxicity, confirming specificity of antibody-mediated neuronal death., Conclusions: Both anti-Hu and anti-Ri antibodies were readily taken up by viable neurons in slice cultures, but the two antibodies differed markedly in terms of their effects on neuronal viability. The ability of anti-Hu antibodies to cause neuronal death could account for the irreversible nature of paraneoplastic neurological deficits in patients with this antibody response. Our results raise questions as to whether anti-Ri antibody might initially induce reversible neuronal dysfunction, rather than causing cell death. The ability of IgG antibodies to access and react with intracellular neuronal proteins could have implications for other autoimmune diseases involving the central nervous system.

Paraneoplastic neurological syndromes (PNS) are associated with small cell lung cancer (SCLC) and Hu antibodies, which are considered to have an immune-mediated etiology. As a pathogenic role for Hu antibodies (Hu-Ab) in PNS could not be demonstrated, the cellular immune response against the Hu proteins has been further investigated. To delve deeper into the hypothesized cell-mediated immune pathogenesis of these syndromes, imbalances within circulating T lymphocyte subsets were investigated to determine their significance in Hu antibody-associated PNS. The circulating T lymphocyte subsets were analyzed in untreated patients with SCLC, PNS and Hu-Ab (n=10), SCLC without PNS (n=10) and healthy controls (n=12) using flow cytometry. Patients with PNS and SCLC, had a variety of changes within their circulating T lymphocyte subsets, which included; lymphopenia of the CD3(+)and CD4(+) T cells, increased proportions of total activated T cells and activated CD4(+) T cells, and reduced numbers of CD4(+) and CD25(+) regulatory T cells (Treg). These results suggest that the excessive activation of T cells and dysfunction of Treg contribute to Hu antibody-associated PNS., (Copyright © 2014 Elsevier Inc. All rights reserved.)

Background and Objective: We investigated if the paraneoplastic Hu and collapsin response mediator protein 5 (CRMP5) antibodies could be used as early markers for lung cancer in smokers with or without chronic obstructive pulmonary disease (COPD)., Methods: Hu and CRMP5 antibodies were measured by radioimmunoprecipitation assay (RIPA) in sera from 552 smokers; 379 with and 173 without COPD. Three hundred blood donors served as controls. The positive sera were also tested by indirect immunofluorescence and line blot with recombinant proteins. The 552 smokers were matched with data from the Cancer Registry of Norway, and the hospital medical records from the subjects positive for Hu and CRMP5 antibodies were reviewed. The mean follow-up time was 4.4 years (range 2.5-5.7 years)., Results: The RIPA showed that 5/379 (1.3%) smokers with COPD had Hu antibodies and 1/379 (0.3%) smokers with COPD had CRMP5 antibodies. Only the smoker with the highest RIPA index had Hu antibodies also detected by immunofluorescence and line blot. One of 173 (0.6%) smokers without COPD had Hu antibodies, but none had CRMP5 antibodies. None of the 300 controls had Hu antibodies, but 2/300 (0.7%) had CRMP5 antibodies. Hu antibodies remained positive for more than 5 years. No cancer or neurological disease was recorded in the Hu or CRMP5 positive patients. The total cancer frequency in the smokers with and without COPD was 70/552 (13%)., Conclusions: Hu and CRMP5 antibodies were not associated with cancer or neurological disease in a large cohort of smokers and are therefore not always paraneoplastic., (© 2014 Asian Pacific Society of Respirology.)

IL-17 is a proinflammatory cytokine produced by activated Th17 cells and other immune cells. IL-17-producing Th17 cells are major contributors to chronic inflammatory and autoimmune diseases, such as multiple sclerosis, rheumatoid arthritis, and inflammatory bowel disease. Although the transcriptional regulation of Th17 cells is well understood, the posttranscriptional regulation of IL-17 gene expression remains unknown. The RNA-binding protein HuR positively regulates the stability of many target mRNAs via binding the AU-rich elements present in the 3' untranslated region of many inflammatory cytokines including IL-4, IL-13, and TNF-α. However, the regulation of IL-17 expression by HuR has not been established. CD4(+) Th17 cells from HuR knockout mice had decreased IL-17 steady-state mRNA and protein levels compared with wild-type Th17 cells, as well as decreases in frequency of IL-17(+) cells. Moreover, we demonstrated that HuR directly binds to the IL-17 mRNA 3' untranslated region by using RNA immunoprecipitation and biotin pulldown assays. In addition, the knockout of HuR decreased cellular proliferation of CD4(+) T cells. Mice with adoptively transferred HuR KO Th17 cells had delayed initiation and reduced disease severity in the onset of experimental autoimmune encephalomyelitis compared with wild-type Th17 cells. Our results reveal a HuR-induced posttranscriptional regulatory mechanism of Th17 differentiation that influences IL-17 expression. These findings may provide novel therapeutic targets for the treatment of Th17-mediated autoimmune neuroinflammation.

Opsoclonus-myoclonus syndrome (OMS) may be associated with ANNA-1 (anti-Hu) autoantibodies. The standard treatment with IVIG, steroids, and anti-CD20 monoclonal antibody may fail, and optimal therapy is unknown. A patient developed OMS with high-titer ANNA-1 following recovery from neuroblastoma. She failed standard therapy and had only transient response to rituximab. Treatment with the humanized anti-CD20 monoclonal antibody ofatumumab combined with methotrexate resulted in transient neurologic improvement and decrease of ANNA-1. This suggests that ofatumumab combined with methotrexate should further be considered OMS patients, particularly in refractory disease., (Copyright © 2013 Wiley Periodicals, Inc.)

In parallel to the detection of new neuronal autoantibodies, the diagnosis of non-infectious limbic encephalitis has risen. Given that cerebral imaging studies show highly variable results, the present retrospective study investigates imaging findings in association with autoantibody type. An institutional database search identified 18 patients with non-infectious limbic encephalitis who had undergone [18F] fluorodeoxyglucose positron emission tomography (FDG-PET). Sixteen of these patients also underwent magnetic resonance imaging (MRI). MRI and FDG-PET images were categorized as follows: normal (0); mesiotemporal abnormality (1); normal mesiotemporal finding but otherwise abnormal (2). Neuronal autoantibodies were determined in serum and/or CSF. Autoantibodies were grouped according to the cellular localization of their target antigen: antibodies against surface antibodies (i.e., VGKC, NMDAR): 9; antibodies against intracellular antigens (i.e., Hu, Ri, GAD): 4; no autoantibodies: 5. The fraction of abnormal scans was lower for MRI (10/16) than for FDG-PET (14/18). There was a significant association between PET findings and autoantibody type: All patients with autoantibodies against intracellular antigens showed mesiotemporal findings on FDG-PET. In turn, only 2/9 patients with autoantibodies against surface antigens displayed mesiotemporal hypermetabolism. In the remaining seven patients, four scans were rated as normal and three only showed findings outside the mesiotemporal region. A similar association was found using MRI, although this did not reach statistical significance. Autoantibody type was found to be associated with FDG-PET and, to a lesser extent, with MRI imaging results. Our observations may explain the heterogeneity of imaging data in LE and based on in vivo findings support the assumption of different patho mechanisms underlying LE due to antibodies against surface and intracellular antigens, respectively.