Clinical presentations and antibody mechanisms in anti-IgLON5 disease.

Anti-IgLON5 disease is a rare neurological disease, identified just ten years ago, where autoimmunity and neurodegeneration converge. The heterogeneity of symptoms, sometimes mimicking pure neurodegenerative diseases or motor neuron diseases, in addition to lack of awareness, represents a diagnostic challenge. Biomarkers of neuronal damage in combination with in vivo visualization of tau deposition using positron emission tomography (PET) scanning could represent a major advance in monitoring disease progression. Recent studies with more autopsies available have helped refine the knowledge of the pathological features of the disease and strengthen the autoimmune hypothesis of the disease. Although the pathogenesis of anti-IgLON5 disease remains unclear, the irreversible antibody-mediated decrease of IgLON5 clusters from the cell surface and alterations produced in the cytoskeleton, as well as the behavioural abnormalities and signs of neuroinflammation and neurodegeneration observed in the brains of animals infused with antibodies from patients by passive transfer, which have recently been published, support the autoimmune hypothesis of the disease. This review aims to summarize these important aspects and recent advances in the pathophysiology of anti-IgLON5 disease.

Randomized clinical trial of pancreaticogastrostomy versus pancreaticojejunostomy on the rate and severity of pancreatic fistula after pancreaticoduodenectomy.

BACKGROUND: Anastomotic leakage of pancreaticojejunostomy (PJ) remains the single most important source of morbidity after pancreaticoduodenectomy (PD). The primary aim of this randomized clinical trial comparing PG with PJ after PD was to test the hypothesis that invaginated PG would result in a lower rate and severity of pancreatic fistula. METHODS: Patients undergoing PD were randomized to receive either a duct-to-duct PJ or a double-layer invaginated PG. The primary endpoint was the rate of pancreatic fistula, using the definition of the International Study Group on Pancreatic Fistula. Secondary endpoints were the evaluation of severe abdominal complications (Clavien-Dindo grade IIIa or above), endocrine and exocrine function. RESULTS: Of 123 patients randomized, 58 underwent PJ and 65 had PG. The incidence of pancreatic fistula was significantly higher following PJ than for PG (20 of 58 versus 10 of 65 respectively; P = 0.014), as was the severity of pancreatic fistula (grade A: 2 versus 5 per cent; grade B-C: 33 versus 11 per cent; P = 0.006). The hospital readmission rate for complications was significantly lower after PG (6 versus 24 per cent; P = 0.005), weight loss was lower (P = 0.025) and exocrine function better (P = 0.022). CONCLUSION: The rate and severity of pancreatic fistula was significantly lower with this PG technique compared with that following PJ. REGISTRATION NUMBER: ISRCTN58328599 (http://www.controlled-trials.com).

The Spanish Pancreatic Club recommendations for the diagnosis and treatment of chronic pancreatitis: part 1 (diagnosis).

Chronic pancreatitis (CP) is a relatively uncommon, complex and heterogeneous disease. The absence of a gold standard applicable to the initial phases of CP makes its early diagnosis difficult. Some of its complications, particularly chronic pain, can be difficult to manage. There is much variability in the diagnosis and treatment of CP and its complications amongst centers and professionals. The Spanish Pancreatic Club has developed a consensus on the management of CP. Two coordinators chose a multidisciplinary panel of 24 experts on this disease. A list of questions was drafted, and two experts reviewed each question. Then, a draft was produced and shared with the entire panel of experts and discussed in a face-to-face meeting. This first part of the consensus addresses the diagnosis of CP and its complications.

The Spanish Pancreatic Club's recommendations for the diagnosis and treatment of chronic pancreatitis: part 2 (treatment).

Chronic pancreatitis (CP) is a complex disease with a wide range of clinical manifestations. This range comprises from asymptomatic patients to patients with disabling symptoms or complications. The management of CP is frequently different between geographic areas and even medical centers. This is due to the paucity of high quality studies and clinical practice guidelines regarding its diagnosis and treatment. The aim of the Spanish Pancreatic Club was to give current evidence-based recommendations for the management of CP. Two coordinators chose a multidisciplinary panel of 24 experts on this disease. These experts were selected according to clinical and research experience in CP. A list of questions was made and two experts reviewed each question. A draft was later produced and discussed with the entire panel of experts in a face-to-face meeting. The level of evidence was based on the ratings given by the Oxford Centre for Evidence-Based Medicine. In the second part of the consensus, recommendations were given regarding the management of pain, pseudocysts, duodenal and biliary stenosis, pancreatic fistula and ascites, left portal hypertension, diabetes mellitus, exocrine pancreatic insufficiency, and nutritional support in CP.

DNA delivery to 'ex vivo' human liver segments.

Hydrodynamic injection is an efficient procedure for liver gene therapy in rodents but with limited efficacy in large animals, using an 'in vivo' adapted regional hydrodynamic gene delivery system. We study the ability of this procedure to mediate gene delivery in human liver segments obtained by surgical resection. Watertight liver segments were retrogradely injected from hepatic vein with a saline solution containing a plasmid bearing the enhanced green fluorescent protein (eGFP) gene, under different conditions of flow rate (1, 10 and 20 ml s(-1)) and final perfused volume. Samples were cultured for 1 to 2 days and used for microscopy and molecular analysis of gene expression. The fluorescent and immunohistochemistry studies indicated that in segments injected at ≥10 ml s(-1), good and wide gene expression was present in the liver sections and the molecular analysis reinforced the histological observation in a quantitative manner (index of apparent gene delivery: 10(2)-10(4) eGFP DNA copy per 100 pg of total DNA; transcription index: 10(5)-2 × 10(6) eGFP RNA copy per 100 ng of total RNA). In addition, injected gold nanoparticles (15 nm diameter) suggested that DNA delivery to hepatocytes must involve a facilitated permeation process without membrane disruption. In summary, we show that retrograde venous injection of watertight human liver segment is an anadromous procedure that results in wide liver gene delivery and good gene expression. However, additional studies will be necessary to clarify the influence of the prolonged ischemia injury to hepatocytes in our model.

Spanish multicenter study of surgical resection of pancreatic tumors infiltrating the celiac axis: does the type of pancreatectomy affect results?

BACKGROUND: Pancreatectomy plus celiac axis resection (CAR) is performed in patients with locally advanced pancreatic cancer. The morbidity rates are high, and no survival benefit has been confirmed. It is not known at present whether it is the type of pancreatectomy, or CAR itself, that is the reason for the high complication rates. METHODS: Observational retrospective multicenter study. INCLUSION CRITERIA: patient undergoing TP, PD or DP plus CAR for a pancreatic cancer. RESULTS: Sixty-two patients who had undergone pancreatic cancer surgery (PD,TP or DP) plus CAR were studied. Group 1: 17 patients who underwent PD/TP-CAR (13TP/4PD); group 2: 45 patients who underwent DP-CAR. Groups were mostly homogeneous. Operating time was longer in the PD/TP group, while operative complications did not differ statistically in the two groups. The number of lymph nodes removed was higher in the PD/TP group (26.5 vs 17.3), and this group also had a higher positive node ratio (17.9% vs 7.6%). There were no statistical differences in total or disease-free survival between the two groups. CONCLUSION: It seems that CAR, and not the type of pancreatectomy, influences morbidity and mortality in this type of surgery. International multicenter studies with larger numbers of patients are now needed to validate the data presented here.

Contaminants of emerging concern in freshwater fish from four Spanish Rivers.

This study investigated the occurrence of 135 contaminants of emerging concern (CECs) - pharmaceuticals, pesticides, a set of endocrine disrupting compounds (EDCs) (parabens, bisphenols, hormones, triazoles, organophosphorus flame retardants and triclosan), UV-filters, perfluoroalkyl substances (PFASs) and halogenated flame retardants (HFRs) - in 59 fish samples, collected in 2010 in 4 Spanish Rivers (Guadalquivir, Júcar, Ebro and Llobregat). Of the 135 CECs, 76 including 8 pharmaceuticals, 25 pesticides, 10 EDCs, 5 UV-filters, 15 PFASs and 13 HFRs were detected. Pharmaceuticals were the less frequently found and at lower concentrations. Pesticides, EDCs, UV-filters, PFASs and HFRs were detected more frequently (>50% of the samples). The maximum concentrations were 15 ng/g dry weight (dw) for pharmaceuticals (diclofenac), 840 ng/g dw for pesticides (chlorpyrifos), 224 ng/g dw for EDCs (bisphenol A), 242 ng/g dw for UV-filters (EHMC), 1738 ng/g dw for PFASs (PFHxA) and 64 ng/g dw for HFRs (Dec 602). The contaminants detected in fish are commonly detected also in sediments. In light of current knowledge, the risk assessment revealed that there was no risk for humans related to the exposure to CECs via freshwater fish consumption. However, results provide detailed information on the mixtures of CECs accumulated that would be very useful to identify their effects on aquatic biota.

Influx of recent thymic emigrants into autoimmune thyroid disease glands in humans.

Autoimmune thyroid diseases (AITD) are considered as prototypic organ-specific autoimmune diseases, yet their underlying aetiology remains poorly understood. Among the various pathophysiological mechanisms considered, a failure of central tolerance has received little attention. Here we present evidence in favour of dysregulated thymic function playing a role in AITD. Flow-cytometric analyses conducted in peripheral blood lymphocytes from 58 AITD patients and 48 age- and-sex-matched controls showed that AITD patients have significantly higher blood levels of CD4(+)CD45RA(+), CD4(+)CD31(+) and CD4/CD8 double-positive T lymphocytes, all markers of recent thymic emigrants (RTE). In addition, the alpha-signal joint T cell receptor excision circles (TRECs) content (a molecular marker of RTEs) was higher in the group of AITD patients older than 35 years than in age-matched controls. This was independent from peripheral T cell expansion as assessed by relative telomere length. Comparisons of TREC levels in peripheral blood lymphocytes and intrathyroidal lymphocytes in paired samples showed higher levels within the thyroid during the initial 30 months of the disease, indicating an influx of RTE into the thyroid during the initial stages of AITD. Additionally, a lack of correlation between TREC levels and forkhead box P3 expression suggests that the intrathyroidal RTE are not natural regulatory T cells. These results uncover a hitherto unknown correlation between altered thymic T cell export, the composition of intrathyroidal T cells and autoimmune pathology.

Analysis of antibodies to neuronal surface antigens in adult opsoclonus-myoclonus.

Antibodies against neuronal surface antigens (NSA-ab) have been described in pediatric opsoclonus-myoclonus syndrome (OMS). We analyzed the presence of NSA-ab by flow cytometry and immunocytochemistry of live cerebellar granular neurons (CGN) in the serum of 25 adult patients with idiopathic (14) and paraneoplastic (11) OMS. Paraneoplastic, but not idiopathic, OMS sera showed a CGN surface binding by flow cytometry higher than that of controls (mean MFI (median fluorescence intensity): 29+/-6.9 vs. 20+/-5.8; p=0.001) but only one serum had a binding greater than three standard deviations of controls. OMS sera did not label live CGN by immunocytochemistry. Unlike pediatric OMS, NSA-ab were not detected in adult cases suggesting that the immunity to NSA in OMS is heterogeneous.

[Autoimmune pancreatitis: inflammatory pseudotumor, multifocal fibrosclerosis, portal hypertension, and long-term outcome]. / Pancreatitis autoinmune: pseudotumor inflamatorio, afectación multifocal, hipertensión portal y evolución a largo plazo.

Autoimmune pancreatitis is a recently characterized disease that still constitutes a diagnostic challenge, especially regarding differential diagnosis from neoplasia. Long-term outcome is poorly known. We herein report a case of a patient with autoimmune pancreatitis and 14 years of follow-up, and show its clinical, biochemical, and morphological characteristics. A 54-year-old female presented with obstructive jaundice and abdominal tenderness, as well as a mass at the pancreatic head on a CT scan, suggestive of pancreatic neoplasia. Surgery showed an increase of the whole pancreas, malignancy was intraoperatively ruled out, and a cholecystectomy and choledochoduodenostomy were carried out. The diagnosis was chronic pancreatitis. Over the following years different autoimmune complications developed, including asthma, salivary gland swelling, and sclerosing cholangitis, as well as recurrent episodes of jaundice, and exocrine and endocrine pancreatic failure. The development of these complications combined with the demonstration of high serum levels of IgG4 and carbonic anhydrase II led to a re-evaluation of the initial histology of the pancreas, leading to a final diagnosis of autoimmune pancreatitis: IgG4+ lymphoplasmacytic infiltrates, fibrosis, and obliterative phlebitis. New complications developed during the last few years: retroperitoneal fibrosis with portal hypertension, esophageal varices, and splenomegaly.

[Parathyroid carcinoma associated to secondary hyperparathyroidism in hemodialyzed patients. Two cases reports]. / Carcinoma de paratiroides asociado a hiperparatiroidismo secundario en pacientes en hemodiálisis.

Parathyroid carcinoma (PC) is an infrequent disease with a subtle initial presentation and a variable course, necessitating a high index of suspicion to make the correct diagnosis. In chronic failure patients on haemodialysis it becomes even more difficult to suspect this entity since the high prevalence of secondary hyperparathyroidism(SHP). Two patients with PC out of a series of 160 patients with moderate-to-severe SHP submitted for parathyroidectomy are reported. Their clinical features are compared with those of the twenty-two cases previously reported in the literature with a discussion of this pathology. Patients with PC showed higher blood levels of iPTH, total calcium, phosphate and total alkaline phosphatase than the SHP population. The final diagnosis of PC was made after histological study revealing capsular or blood vessel invasion.

Co-administration of pentoxifylline and thiopental causes death by acute pulmonary oedema in rats.

BACKGROUND AND PURPOSE: Pentoxifylline exhibits rheological properties that improve microvascular flow and it is widely used in vascular perfusion disorders. It also exhibits marked anti-inflammatory properties by inhibiting tumour necrosis factor alpha production. Thiopental is one of the most widely used drugs for rapid induction of anaesthesia. During experimental studies on the treatment of acute pancreatitis, we observed that when pentoxifylline was administered after anaesthesia with thiopental, most of the rats exhibited dyspnea, signs of pulmonary oedema and died. The aim of the work described here was to investigate the cause of the unexpected toxic effect of the combined treatment with thiopental and pentoxifylline. EXPERIMENTAL APPROACH: Pulmonary vascular permeability and arterial blood gases were measured, and a histological analysis was performed. The possible role of haemodynamic changes in the formation of pulmonary oedema was also assessed. KEY RESULTS: Co-administration of pentoxifylline and thiopental increased pulmonary vascular permeability and markedly decreased arterial pO2, with one third of rats suffering from hypoxemia. This combined treatment caused death by acute pulmonary oedema in 27% of normal rats and aggravated the respiratory insufficiency associated with acute pancreatitis in which the mortality rate increased to 60%. This pulmonary oedema was not mediated by cardiac failure or by pulmonary hypertension. CONCLUSIONS AND IMPLICATIONS: Co-administration of pharmacological doses of pentoxifylline and thiopental caused pulmonary oedema and death in rats. Consequently, pentoxifylline should not be administered when anaesthesia is induced with thiopental to avoid any possible risk of acute pulmonary oedema and death in humans.

Protein kinase Cgamma autoimmunity in paraneoplastic cerebellar degeneration and non-small-cell lung cancer.

BACKGROUND: The clinical and immunological profiles of patients with paraneoplastic cerebellar degeneration (PCD) and non-small-cell lung cancer (NSCLC) are not well known. OBJECTIVE: To review the clinical and immunological features of patients with PCD, NSCLC and without well-characterised onconeural antibodies. METHODS: The clinical features of nine patients with the diagnosis of classical PCD and NSCLC, included in our archives, were retrospectively reviewed. The presence of antibodies to cerebellar components was determined by immunohistochemistry and immunoblot of rat cerebellum. A cDNA library of human cerebellum was screened with the positive sera to identify the antigen. RESULTS: Nine patients with PCD and NSCLC were identified. Six patients were men, and the median age at diagnosis of PCD was 63 (range 47-73) years. PCD was completely reversed in two patients, and partially in one, after treatment of the tumour. The serum of one of the patients with PCD showed a unique reactivity with Purkinje cells. The screening of a cerebellar-expression library resulted in the isolation of protein kinase Cgamma (PKCgamma). PKCgamma immunoreactivity was not observed in the serum of 170 patients with non-paraneoplastic neurological syndromes, 27 patients with PCD, no onconeural antibodies and small-cell lung cancer, and 52 patients with NSCLC without paraneoplastic neurological syndromes. The NSCLC from 11 patients without PCD did not express PKCgamma at either the RNA or protein level. However, many cells of the NSCLC of the patient with PKCgamma antibodies expressed PKCgamma. CONCLUSION: PCD occurs in patients with NSCLC without typical onconeural antibodies and is associated with immune reactions against key proteins of the Purkinje cells.

Anti-glial nuclear antibody: marker of lung cancer-related paraneoplastic neurological syndromes.

We describe a new antibody, called anti-glial nuclear antibody (AGNA), in patients with paraneoplastic neurological syndromes (PNS) and small-cell lung carcinoma (SCLC). AGNA was initially identified in 24 sera of our archives by immunohistochemistry on rat cerebellum. AGNA positive sera showed a characteristic nuclear staining of the Bergmann glia in the Purkinje cell layer. Immunoblots and probing a cerebellar expression library with AGNA sera did not identify the antigen. Twenty of the 24 patients with AGNA had PNS and all but two had lung cancer. AGNA was identified in 13/113 (11.5%) patients with SCLC compared with 0/122 with other types of cancer (p<0.0001). The frequency of AGNA was not higher than expected for the presence of SCLC in the different PNS subtypes except in LEMS (p=0.0002). AGNA was present in 13/30 (43%) of LEMS patients with SCLC, compared with 0/19 of LEMS patients without cancer (p=0.0006). We conclude that the recognition of AGNA is helpful since this antibody is found in PNS associated with SCLC, particularly LEMS, in which other onconeural antibodies are absent.

Recurrence of immunological markers for type 1 (insulin-dependent) diabetes mellitus in immunosuppressed patients after pancreas transplantation.

BACKGROUND: Type 1 (insulin dependent) diabetes mellitus (IDDM) is an autoimmune disease in which autoantibodies against islet cells develop concomitantly with or even preceding diagnosis. Because the recurrence of diabetes can be the cause of graft failure in patients with pancreas transplantation, we studied the possible recurrence of IDDM immunomarkers after transplantation. METHODS: The following determinations were performed every 1-2 years after transplantation in 50 immunosuppressed IDDM patients with simultaneous kidney and pancreas transplantation (bladder drainage of exocrine secretion): islet cell antibodies (ICA) by direct immunofluorescence, antibodies against glutamic acid decarboxylase (GADab) by radiobinding assay, and the oral glucose tolerance test. The mean follow-up was 4.1+/-6.3 (range 1 to 9 years). RESULTS: GADab were detected in 11 patients after transplantation, 10 of whom had been positive beforehand. ICA reappearance after transplantation was detected in seven patients (14%). The presence of ICA was related to GADab positivity (P=0.001) and HLA DR3 patients (P=0.04), but not with pancreatitis and rejection episodes, immunosuppression induction therapy, or donor HLA haplotype. During follow-up, an abnormal oral glucose tolerance test was more frequent in ICA-positive patients (P=0.02), with no differences in metabolic control or insulin secretion. CONCLUSION: We conclude that GADab persist and ICA reappear despite immunosuppressive therapy in patients with functioning pancreas transplants. The relevance and the risk that this implies for IDDM development should be determined.

Role of cytokines and oxidative stress in the pathophysiology of acute pancreatitis: therapeutical implications.

Severe acute pancreatitis causes a high incidence of mortality due to the systemic inflammatory response syndrome leading to multiple organ failure. At present, there is no treatment against severe acute pancreatitis, other than supportive critical care. The relationship between pancreatic injury and the uncontrolled systemic response is not completely understood. Nevertheless, experimental and clinical evidences have shown that pro-inflammatory cytokines and oxidative stress are critically involved in the development of local and systemic complications associated with severe acute pancreatitis. Serum levels of pro-inflammatory cytokines, such as TNF-alpha and IL-1beta, increase during the course of acute pancreatitis and they appear to be the driving force for the initiation and propagation of the systemic response. Accordingly, pretreatment with an antibody against TNF-alpha or blockade of TNF-alpha production with pentoxifylline ameliorates experimental acute pancreatitis. In addition, serum IL-6 and IL-8 levels appear to be correlated with severity of pancreatic inflammation. The role of oxidative stress in acute pancreatitis has been evidenced indirectly by beneficial effects of antioxidants as well as directly by pancreatic glutathione depletion and increased lipid peroxidation. Furthermore, circulating xanthine oxidase released by the damaged pancreas acts as a source of systemic oxidative stress contributing to lung inflammation. In conclusion, pancreatic injury seems to trigger at least two different pathways, i.e. pro-inflammatory cytokines and oxidative stress, both involved in the systemic effects of acute pancreatitis. Elucidation of these mechanisms and their interactions is critical to develop a treatment based on the pathophysiology of acute pancreatitis.

Conservative pancreatic resection in patients with obstructive chronic pancreatitis.

The purpose of this paper is to present the results of our experience in using a conservative pancreatic resection approach in a certain group of patients suffering from chronic pancreatitis. From January 1988 to December 1995, 110 patients underwent surgical therapy for chronic pancreatitis at the Hospital Clinic of the University of Barcelona. In 35 patients with an inflammatory mass at the pancreatic head, pylorus-preserving duodeno-pancreatectomy was performed. Forty male patients with localized focal pancreatitis at the body or tail underwent distal pancreatectomy and drainage of the pancreatic remnant. In 30 patients with pancreatic ducts greater than 7 mm in diameter, side-to-side pancreaticojejunostomy was carried out. Five patients could not be included in any of these three categories because of their particular characteristics. In all cases, resolution of the symptoms was achieved at the mean follow-up of 18 months (range 12 to 21 months). No patient showed a deterioration of glucose homeostasis, and exocrine dysfunction was not observed. Patients with obstructive chronic pancreatitis by inflammatory cystic mass, short strictures or intraductal stones located in the central pancreas or uncinate process may be surgically managed with conservative pancreatic resection or extraction of the stones from the Wirsung duct. The jejunal interposition and pancreaticojejunal anastomosis achieved pain control without any deterioration of the endocrine or exocrine function.

[Usefulness of ultrasonography and computerized tomography in predicting resectability of pancreatic carcinoma]. / Utilidad de la ultrasonografía y la tomografía computarizada en la predicción de la resecabilidad del carcinoma pancreático.

BACKGROUND: Surgical resection is the only curative treatment of pancreatic carcinoma (PC). An accurate assessment of the extension of PC is mandatory to select appropriate patients to this therapeutic option. This study was aimed at assessing the usefulness of abdominal ultrasonography (US) and computed tomography (CT) to establish tumoral staging and to predict tumor resectability. PATIENTS AND METHODS: Between January 1990 and December 1995, 84 PC patients were submitted to surgical procedures (potentially curative resection in 30%, biliodigestive anastomosis in 51% and exploratory laparotomy in 13%). Preoperative staging was carried out by means of abdominal US and/or CT. Definitive staging was established according to surgical findings, using the TNM classification. RESULTS: Accuracy of preoperative evaluation with regard to tumoral staging was 65%, being underestimated in 29 (35%) patients. This underestimation was mainly due to lesions in stage I. In addition, preoperative staging predicted tumor unresectability with a 50% sensitivity and a 83% specificity. CONCLUSIONS: US and CT have a good specificity in the staging and unresectability prediction of pancreatic cancer. However, their usefulness is limited by their low sensitivity.

GABA(B) receptor antibodies in limbic encephalitis and anti-GAD-associated neurologic disorders.

BACKGROUND: γ-Aminobutyric acid-B receptor antibodies (GABA(B)R-ab) were recently described in 15 patients with limbic encephalitis (LE), associated with small-cell lung cancer (SCLC) or with concurrent glutamic acid decarboxylase (GAD) antibodies. We analyzed the frequency of GABA(B)R-ab in 147 patients with LE or neurologic syndromes associated with GAD-ab. METHODS: We examined the presence of GABA(B)R-ab in 70 patients with LE (33 paraneoplastic with onconeural antibodies, 18 paraneoplastic without onconeural antibodies [5 with Gad-ab], and 19 idiopathic with either GAD-ab [5 patients] or seronegative) and 77 patients with GAD-ab-associated neurologic syndromes other than LE (29 stiff-person syndrome, 28 cerebellar ataxia, 14 epilepsy, and 6 with diverse paraneoplastic neurologic syndromes). GABA(B)R-ab were analyzed in serum or CSF by indirect immunofluorescence on HEK293 cells transfected with GABA(B1) and GABA(B2) receptor subunits. RESULTS: GABA(B)R-ab were detected in 10 of the 70 patients with LE (14%). Eight had SCLC and 2 were idiopathic. One of the 8 patients with LE with SCLC had an additional onconeural antibody (Hu) and 2 GAD-ab. GABA(B)R-ab were identified in 7 (70%) of the 10 patients with LE and SCLC without onconeural antibodies. GABA(B)R-ab antibodies were not found in patients with GAD-ab and stiff-person syndrome, idiopathic cerebellar ataxia, or epilepsy. However, one patient with GAD-ab, paraneoplastic cerebellar ataxia, and anaplastic carcinoid of the thymus also presented GABA(B)R-ab. CONCLUSIONS: GABA(B)R-ab are the most common antibodies found in LE associated with SCLC previously considered "seronegative." In patients with GAD-ab, the frequency of GABA(B)R-ab is low and only observed in the context of cancer.