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The appearance of a paraneoplastic neurological disorder (PND) with Hu-antibodies, often before tumour detection, together with spontaneous tumour regression in a few patients, suggests that immune responses to HuD, possibly mediated by cytotoxic T-cells, could be beneficial to the patient.1 Nevertheless, in previous retrospective studies, survival in Hu-antibody-associated PNDs (Hu-Ab/PNDs) in general was similar to those in patients with small-cell lung cancer (SCLC) without neurological illness.2 3 Here we studied, for the first time prospectively, tumour outcomes in a large series of patients with Hu-Ab/PNDs, comparing with contemporaneous patients with SCLC without neurological symptoms. ### Patients Written consent was obtained from all patients. From July 2012 to June 2015 prospectively we collected all serum samples that were positive for Hu-antibodies at Oxford University Hospitals as part of routine diagnostic testing via referral from any of England’s 152 acute hospital trusts. Diagnostic categorisation of associated PNDs was agreed between the research team and the referring physician, in line with published diagnostic criteria.4 For survival comparisons, contemporaneous control data and pre-treatment serum samples were obtained prospectively from 245 patients with SCLC, without PNDs, from the Nottingham Trent region over the same time period. Serum samples were stored at −80°C and retested for Hu and SOX2 antibodies by ELISA, and paraneoplastic antibodies tested on frozen rat cerebellum with positive results confirmed using a multi-line blot (Ravo Diagnostika, Freiburg, Germany) (see online supplemental methods). ### Supplementary data [jnnp-2021-326067supp001.pdf] ### Statistical analysis Survival statistics from date of SCLC diagnosis in PND and control groups were calculated using log-rank tests, and differences in cancer survival according to presence of PNDs and Hu-antibodies were evaluated using a Cox proportional hazards model. ### Patients with Hu-antibody PNDs and SCLC controls One …

Introduction Autoantibodies against the extracellular domains of the voltage-gated potassium channel (VGKC) complex proteins, leucine-rich glioma-inactivated 1 (LGI1) and contactin-associated protein-2 (CASPR2), are found in patients with limbic encephalitis, faciobrachial dystonic seizures, Morvan’s syndrome and neuromyotonia. However, in routine testing, VGKC-complex-antibodies without LGI1- or CASPR2-reactivities (‘double-negative’) are commoner than LGI1- or CASPR2-specificities. Therefore, the target (s) and clinical associations of double-negative antibodies need to be determined. Methods Sera (n=1131) from several clinically-defined cohorts were tested for IgG-radioimmunoprecipitation of 125I-aDTX-labelled VGKC-complexes, 125I-aDTX and 125I-aDTX-labelled Kv1-subunits, live hippocampal neuron reactivity, and by cell-based assays using Kv1-subunits, LGI1 and CASPR2. Results VGKC-complex-antibodies were found in 162 of 1131 (14%) sera. Ninety of these (56%) had antibodies targeting the extracellular domains of LGI1 or CASPR2. Of the remaining 72 double-negative sera, ten (14%) immunoprecipitated 125I-aDTX itself, and 27 (38%) bound to solubilized co-expressed Kv1.1/1.2/1.6 subunits and/or Kv1.2 subunits alone, at levels proportionate to VGKC-complex-antibody levels (r=0.57, p=0.0017). The Kv1-precipitating samples only bound to permeabilised Kv1-expressing HEK cells. These intracellular Kv1-antibodies mainly associated with non-immune disease aetiologies, poor longitudinal clinical-serological correlations, and a limited immunotherapy-response. Conclusions Double-negative VGKC-complex-antibodies are often directed against cytosolic epitopes of Kv1-subunits, and occasionally against non-mammalian aDTX. These are not neuronal-surface antibodies. They consequently lack pathogenic potential, and do not in themselves support use of immunotherapies. VGKC-complex radioimmunoassay testing should cease; antibodies against LGI1 and CASPR2 provide greater specificity and sensitivity.

Systemic Lupus Erythematosis (SLE) is a multi-system autoimmune disease. Putative biomarkers for neuropsychiatric SLE (NPSLE) include antibodies against the DWEYS peptide, a sequence present on the extracellular portion of NR2A/B receptors. We tested for binding of antibodies to conformational state neuronal proteins, including the NMDA receptor to understand potential pathogenicity of these antibodies. Paired serum and CSF from 35 patients SLE/NPSLE were studied. No binding was observed to natively expressed NMDARs or live hippocampal neurons. A DWEYS-reactive ELISA showed by comparison to healthy controls, SLE patients (p=0.0001) and disease-controls (predominantly MS (n=36, (p=0.016)) but not antibody-controls (aquaporin-4- (n=11), LGI1- (n=13) and NMDAR- (n=10) antibody diseases, p=0.375) showed greater binding, suggesting this assay is not selective for NPSLE/SLE. Binding was unaffected by a scrambled or charge altered DWEYS peptide. However, the same samples also showed similar binding to the plate without the DWEYS peptide. Uncoated versus coated plate ELISA data showed Spearman’s correlations>0.79 across all cohorts. NPSLE does not associate with antibodies to NR1 or NR2A/B homomers/heteromers or cultured hippocampal neurons in their native, conformational state. The DWEYS assay is not a reliable way to test for NPSLE, and literature discrepancies may result from the propensity of SLE patients to bind ELISA plates. We would not recommend further use or exploration of the DWEYS assay in SLE.

The aims of the Lambert-Eaton myasthenic syndrome (LEMS) British Neurological Surveillance Unit (BNSU) survey was four-fold: firstly, to allow data collection on LEMS patients to establish a cohort of cases prospectively in order to determine, without bias, whether SCLC-LEMS patients survive longer than patients with SCLC without LEMS; secondly, to collect large serum samples to store as part of a LEMS biobank; thirdly to use previously published DELTA-P predictive scores prospectively in a real-world setting to measure its effectiveness in predicting cancer in LEMS patients at first diagnosis; and fourthly to test LEMS patients for the presence of other neuronal antibodies that may also be predictive of cancer. Between March 2010 and January 2017, we were notified of 111 new LEMS cases via the BNSU of the Association of British Neurologists. Of these, 45 (41%) LEMS patients returned a signed consent to us, and enrolled in the study. Ongoing survival data using multivariate Cox regression analysis showed that the presence of LEMS with SCLC conferred a significant survival advantage independent of the other prognostic variables (Hazard ratio 0.569, 95% CI 0.368–0.880, p=0.011). DELTA-P score was confirmed to aid in determining SCLC probability, with area under the ROC curve of 83.4%.

Epilepsy is one of the most frequent neurological disorders affecting between 0.5% and 1% of the population, but in many the aetiology is unknown. A recent population-based study reported a fivefold increase in patients with type 1 diabetes mellitus (T1DM).1 Autoantibodies that recognise neuronal proteins have been identified in a number of immunotherapy-responsive seizure-related neurological disorders.2 High-titre autoantibodies to glutamic acid decarboxylase (GAD), an intracellular enzyme that catalyses the synthesis of gamma-aminobutyric acid (GABA) have been detected in neurological diseases including epilepsy although these patients show a less clear response to immunotherapies.3 ,4 GAD is also expressed by pancreatic β cells and is a major autoantigen in T1DM. Antibodies to GAD (GAD Abs) are present in up to 80% of patients with newly diagnosed T1DM, although not considered causative. There have been studies examining the incidence of GAD Abs in patients with epilepsy;5 however, we compare GAD and other Abs in patients with T1DM, with and without epilepsy. ### Study design and participants We recruited patients with T1DM (n=25) and coexistent epilepsy (T1DM/Ep) and sex-matched/age-matched patients with T1DM (n=36) from Nottingham and Sheffield Teaching Hospitals NHS Trust; the diagnoses of epilepsy and T1DM were established by specialist neurology (PM and SH) and diabetology (II) teams. Ethics approval was obtained, and written informed consent was obtained from all patients involved. ### Radioimmunoassays Voltage-gated potassium channel (VGKC)-complex antibodies were determined by immunoprecipitation of 125I-α-dendrotoxin-labelled VGKC complexes from rabbit brain extract (positive >100 pmoles/L).5 GAD65 Abs were measured using …

Recent studies have identified antibodies to the SOXB1 group of proteins in patients with paraneoplastic disorders (PNDs) associated with small-cell lung cancer (SCLC), particularly Lambert-Eaton myasthenic syndrome (LEMS), but rarely in non-tumour LEMS, indicating that these antibodies may be useful paraneoplastic biomarkers. We aimed to establish if SOX antibodies could be used to identify underlying tumours in a range of PNDs, including control tumour groups. We established a SOX2 ELISA with high test-retest reproducibility. Positivity to SOX2 in control patients without neurological symptoms was 77/259 (30%) in SCLC, but only 15/238 (6%) in non-SCLC, 0/75 in breast cancer, 3/104 (3%) in ovarian cancer, and 12/414 (3%) in age matched healthy controls. Antibodies to SOX2 were detected in 39/71 (55%) patients with LEMS-SCLC, and 7/105 (6.6%) patients with non-tumour LEMS (p 90%) markers for SCLC, but not other tumours, in patients with PNDs, particularly LEMS with or without ataxia.

LE defines the subacute onset of amnesia and seizures. However, there are few reliable clinical features distinguishing VGKC-antibody associated LE from the many other forms of LE. Identification of such features may aid early diagnosis and immunotherapy administration. We describe 26 patients with median age at onset of 64.5 years (36–73) who developed characteristic, brief (few seconds), frequent (mean of 65 per day) dystonic seizures involving the arm (in 100%) and face (in 73%). All patients had high VGKC-antibody levels (mean 2403 pM, 238–6129; normal values

Type 1 anti-neuronal nuclear antibody (ANNA-1), also known as anti-Hu, recognises a family of RNA binding proteins, expressed in neuronal nuclei throughout the human neuraxis. Its presence usually reflects immunity against neuroendocrine tumours, in particular small-cell-lung cancer (SCLC). When present with neurological symptoms, anti-Hu is diagnostic of a paraneoplastic syndrome according to published criteria. A 72-year-old woman with a 39 pack-year smoking history developed a subacute sensory neuronopathy and weight loss attributed to a nonmetastatic chest neoplasm. High titres of anti-Hu antibodies were detected. Her chest mass was completely resected and found immunohistochemically to be homogenous squamous cell carcinoma. PET imaging has not revealed a second tumour to date. We demonstrated Hu antigen positivity on immunoblot of patient sera before and after surgery. Sections of the patient9s tumour were incubated with sera at 1:20 dilution for 1 h. We demonstrated immunoreactivity in sera from the patient, and a Hu-positive patient with SCLC; this was specific to the large nuclei of the patient9s squamous cell tumour, indicating tumour anti-Hu immunoreactivity. Control sera (from a patient with SCLC and a healthy control) did not show any staining. In rare cases the tumour giving rise to anti-Hu antibody associated sensory neuronopathy may be the result of squamous metaplasia. This should be borne in mind when initial tumour surveillance fails to detect SCLC.