anti-GAD Autoantibodies Research Articles

Autoimmune Retinopathy in a Patient with Stiff-Person Syndrome: A Case Report.

To describe a patient who developed retinal degeneration associated with autoimmune retinopathy (AIR) and who was also found to have anti-glutamic acid decarboxylase (GAD65) autoantibodies and the diagnosis of stiff-person syndrome (SPS). Ophthalmologic workup consisted of clinical examination, multi-modality retinal imaging, and electrophysiologic testing. Further neurologic assessment including relevant serum and cerebrospinal fluid studies was also conducted. We highlight the case of a 45-year-old patient who developed subacute, sequential vision loss, along with bilateral lower extremity weakness. On initial presentation, optical coherence tomography (OCT) of the left eye was notable for diffuse attenuation of the outer retinal bands. Fundus autofluorescence demonstrated a ring of hyper-autofluorescence encircling the fovea of the left eye. At fifteen-month follow-up, the right eye also became similarly affected. He was found to have elevated serum and cerebrospinal anti-GAD65 autoantibodies and was diagnosed with both SPS and AIR. There is a potential association of anti-GAD65 autoantibodies with the development of AIR.

Anti-CASPR2, Anti-LGI1, and Anti-GAD65 Autoantibodies in Patients with Intractable Epilepsy

Abstract Background Autoimmunity is increasingly being recognized as a cause of intractable epilepsy. The autoimmune epilepsies (AE) are immunologically mediated disorders in which recurrent seizures are a primary and persistent clinical feature. When other etiologies have been excluded, an autoimmune etiology of epilepsy is suggested in the presence of resistance to anti-epileptic drugs (AED). In such patients, immunotherapy may be highly effective, depending on the particular autoimmune epilepsy syndrome present. Objective To investigate the presence of Contactin associated protein like 2 (CASPR2), leucine rich Glioma inactivated1 (LGI1) and Glutamic acid decarboxylase 65 (GAD65) autoantibodies in intractable epilepsy, and their association with clinical and imaging findings. Subjects and Methods Seventeen patients with intractable epilepsy were included. LGI1, CASPR2 and GAD65 autoantibodies testing by indirect immunofluorescence cellbased assay in both serum and cerebrospinal fluid (CSF) were assessed in all patients. Results Both serum and CSF samples of the 17 patients were tested negative for the 3 autoantibodies (Anti CASPR2, Anti LGI1 and Anti GAD 65). Regarding CSF examination, only 5 patients had normal CSF, the other 12 showed some changes; 7 had elevated levels of proteins, 3 showed positive oligoclonal bands and elevated IgG index and 2 patients showed both elevated proteins and cells. Conclusion Some cases of AE are associated with specific autoantibodies to neuronal proteins. Clinicians must make a diagnosis based on a combination of clinical phenotypes, CSF results, and neuroimaging. Meanwhile, patients should be followed-up systematically due to the constant discovery of new neuronal auto antibodies.

Anti-GAD65 autoantibody levels measured by ELISA and alternative types of immunoassays in relation to neuropsychiatric diseases versus diabetes mellitus type 1.

Anti-GAD65 autoantibodies (GAD65-Abs) may occur in patients with epilepsy and other neurological disorders, but the clinical significance is not clear-cut. Whereas high levels of GAD65-Abs are considered pathogenic in neuropsychiatric disorders, low or moderate levels are only considered as mere bystanders in, e.g., diabetes mellitus type 1 (DM1). The value of cell-based assays (CBA) and immunohistochemistry (IHC) for GAD65-Abs detection has not been clearly evaluated in this context. To re-evaluate the assumption that high levels of GAD65-Abs are related to neuropsychiatric disorders and lower levels only to DM1 and to compare ELISA results with CBA and IHC to determine the additional value of these tests. 111 sera previously assessed for GAD65-Abs by ELISA in routine clinical practice were studied. Clinical indications for testing were, e.g., suspected autoimmune encephalitis or epilepsy (neuropsychiatric cohort; n = 71, 7 cases were initially tested positive for GAD65-Abs by ELISA), and DM1 or latent autoimmune diabetes in adults (DM1/LADA cohort (n = 40, all were initially tested positive)). Sera were re-tested for GAD65-Abs by ELISA, CBA, and IHC. Also, we examined the possible presence of GAD67-Abs by CBA and of other neuronal autoantibodies by IHC. Samples that showed IHC patterns different from GAD65 were further tested by selected CBAs. ELISA retested GAD65-Abs level in patients with neuropsychiatric diseases was higher than in patients with DM1/LADA (only retested positive samples were compared; 6 vs. 38; median 47,092 U/mL vs. 581 U/mL; p = 0.02). GAD-Abs showed positive both by CBA and IHC only if antibody levels were above 10,000 U/mL, without a difference in prevalence between the studied cohorts. We found other neuronal antibodies in one patient with epilepsy (mGluR1-Abs, GAD-Abs negative), and in a patient with encephalitis, and two patients with LADA. GAD65-Abs levels are significantly higher in patients with neuropsychiatric disease than in patients with DM1/LADA, however, positivity in CBA and IHC only correlates with high levels of GAD65-Abs, and not with the underlying diseases.

Wernicke’s Encephalopathy Preceded by COVID-19 Infection: A Case Report (P2-7.006)

<h3>Objective:</h3> To describe a case of post-infectious encephalopathy following COVID-19 with MRI brain changes suggestive of Wernicke’s encephalopathy and a transient presence of anti-GAD65 autoantibodies in the cerebrospinal fluid (CSF). <h3>Background:</h3> Chronic malnutrition and alcoholism are known risk factors for developing Wernicke’s encephalopathy. However, it is not typically associated with thiamine deficiency resulting from acute starvation as in this case of severe respiratory syndrome due to coronavirus-2 (SARS-CoV-2). <h3>Design/Methods:</h3> NA <h3>Results:</h3> A 59 year-old female presented to the neurointensive care unit with subacute disorientation, decreased verbal fluency, memory deficits, gait dysfunction, confusion, and rapid weight loss that progressed to coma over two months following COVID-19 infection. Initial lumbar puncture (LP) one month following infection was notable for positive anti-GAD65 autoantibodies and elevated protein which was suggestive of post-infectious encephalitis. MRI brain at the time of initial evaluation was unremarkable for abnormalities and the patient’s symptoms continued to progress to include depressed mentation. Subsequent MRIs of the brain with and without contrast showed T2 FLAIR abnormalities in the periaqueductal grey, lateral walls of the third ventricle, splenium, and mammillary bodies. Repeat LP showed similar CSF profile and absence of anti-GAD65 autoantibodies. Electroencephalogram showed slowing with frequent generalized periodic discharges. Patient’s treatment course included high dose thiamine, methylprednisolone, intravenous immunoglobulin, and plasmapheresis without clinical improvement. The patient did not show meaningful cognitive recovery and was transitioned to comfort care. <h3>Conclusions:</h3> The patient’s progression to coma was suspected to be due to development of COVID-19 encephalopathy precipitating Wernicke’s encephalopathy in the setting of severely diminished oral intake. Because Wernicke’s encephalopathy is potentially reversible with thiamine administration, we propose that early empiric treatment should be considered in all patients suffering from persistent encephalopathy following COVID-19 infection. <b>Disclosure:</b> Dr. Volski has nothing to disclose. Dr. Wang has nothing to disclose. Dr. Chakrabarti Pulakanti has nothing to disclose. Dr. Dolla has nothing to disclose.

Late-Onset Cerebellar Ataxia Associated with Anti-GAD Autoantibodies: A Rare and Puzzling Disease (P4-5.013)

Late-Onset Cerebellar Ataxia Associated with Anti-GAD Autoantibodies: A Rare and Puzzling Disease (P4-5.013)

F-18 Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography Muscle Uptake in Antiglutamic Acid Decarboxylase Antibody-positive Stiff-person Syndrome.

Antiglutamic acid decarboxylase-65 (anti-GAD65) autoantibodies have been identified in variety of rare neurologic disorders most frequently in stiff-person syndrome (SPS), condition characterized by muscle rigidity and overlying painful spasms, typically affecting axial and limb musculature. In anti-GAD65-related neurologic disorder, malignancy screening is often performed with 18F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT). Here, we present an interesting image of 18FFDG PET/CT whole body showing muscle uptake and FDG brain showing thalamic hypometabolism in SPS.

Evaluation of glutamic acid decarboxylase (GAD) 65 antibody detection methods for neurological and diabetic investigation in an Australian diagnostic laboratory

The role of anti-glutamic acid decarboxylase (GAD) 65 autoantibodies in autoimmune neurological conditions is evolving, but testing recommendations remain unchanged in Australia with GAD enzyme-linked immunosorbent assay (ELISA) and immunoblot as the only two Therapeutic Goods Administration approved testing methods available in Australia. Common practice is for use of ELISA in diagnosis of type 1 diabetes mellitus (T1DM) and use of immunoblot for diagnosis of GAD65-associated neurological disease. We observed a cohort of patients with negative immunoblot results and positive ELISA in the context of GAD-associated neurological disease without T1DM. In the absence of robust consensus guidelines on preferred testing modalities, we sought to determine if ELISA could have a superior role in the diagnosis of GAD-associated neurological disease when compared to immunoblot in this paper. We tested for anti-GAD65 autoantibodies on 55 patient samples, 40 samples requested for neurological disease and 15 type 1 diabetes samples with detectable anti-GAD65, using two testing platforms: Euroimmun anti-GAD enzyme-linked immunosorbent assay (ELISA) and. Euroimmun EuroLine immunoblot for paraneoplastic neurologic syndromes. These results were correlated against the clinical scenario. Positive ELISA results had a sensitivity of 100% and specificity of 91% for GAD65-related neurological disease. Immunoblot showed sensitivity of 43% and specificity of 76% for GAD65-related neurological disease. ELISA proved more sensitive and specific for GAD65-related neurological disease compared to immunoblot, raising questions about the role of this testing modality in neurological disease. We propose that ELISA should be used as a sole diagnostic method for all GAD65 antibody-related neurological disease over immunoblot. The presence of anti-GAD65 antibody on immunoblot is of doubtful clinical significance.

The evaluation of pancreas β-cell autoantibodies in non-diabetic COVID-19 patients.

This study aims to evaluate potential pancreas endocrine damage due to SARS-CoV-2 by measuring β-cell autoantibodies in COVID-19 patients. Between June and July 2020, 95 inpatients with a positive COVID-19 test result after polymerase-chain-reaction (PCR) and who met the inclusion criteria were enrolled in our study. Laboratory parameters that belong to glucose metabolism and β-cell autoantibodies, including anti-islet, anti-glutamic acid decarboxylase, and anti-insulin autoantibodies, were measured. β-cell autoantibodies levels of the patients were measured during COVID-19 diagnosis. Positive results were reevaluated in the 3rd month of control. In the initial evaluation, 4 (4.2%) patients were positive for anti-islet autoantibody. Only one (1.1%) patient was positive for anti-glutamic acid decarboxylase autoantibody. No patient had positive results for anti-insulin autoantibody. FPG, HbA1c, and C-peptide levels were similar in patients who were split into groups regarding the initial positive or negative status of anti-islet and anti-GAD autoantibodies (p>0.05). In the 3rd month after the initial measurements, anti-islet autoantibody positivity of 2 (50%) of 4 patients and anti-glutamic acid decarboxylase positivity of 1 (100%) patient were persistent. Finally, 3 (3.1%) patients in the whole group were positive for anti-islet autoantibody in the 3rd month of control. No difference was determined between the initial and the 3rd month of parameters of glucose metabolism. Following an ongoing autoantibody positivity in the present study brings the mind that SARS-CoV-2 may be responsible for the diabetogenic effect. Clinicians should be aware of autoantibody-positive DM as a potential autoimmune complication in patients with SARS-CoV-2.

A genome-wide association study in autoimmune neurological syndromes with anti-GAD65 autoantibodies.

Autoimmune neurological syndromes (AINS) with autoantibodies against the 65 kDa isoform of the glutamic acid decarboxylase (GAD65) present with limbic encephalitis, including temporal lobe seizures or epilepsy, cerebellitis with ataxia, and stiff-person-syndrome or overlap forms. Anti-GAD65 autoantibodies are also detected in autoimmune diabetes mellitus, which has a strong genetic susceptibility conferred by human leukocyte antigen (HLA) and non-HLA genomic regions. We investigated the genetic predisposition in patients with anti-GAD65 AINS. We performed a genome-wide association study (GWAS) and an association analysis of the HLA region in a large German cohort of 1214 individuals. These included 167 patients with anti-GAD65 AINS, recruited by the German Network for Research on Autoimmune Encephalitis (GENERATE), and 1047 individuals without neurological or endocrine disease as population-based controls. Predictions of protein expression changes based on GWAS findings were further explored and validated in the CSF proteome of a virtually independent cohort of 10 patients with GAD65-AINS and 10 controls. Our GWAS identified 16 genome-wide significant (P < 5 × 10-8) loci for the susceptibility to anti-GAD65 AINS. The top variant, rs2535288 [P = 4.42 × 10-16, odds ratio (OR) = 0.26, 95% confidence interval (CI) = 0.187-0.358], localized to an intergenic segment in the middle of the HLA class I region. The great majority of variants in these loci (>90%) mapped to non-coding regions of the genome. Over 40% of the variants have known regulatory functions on the expression of 48 genes in disease relevant cells and tissues, mainly CD4+ T cells and the cerebral cortex. The annotation of epigenomic marks suggested specificity for neural and immune cells. A network analysis of the implicated protein-coding genes highlighted the role of protein kinase C beta (PRKCB) and identified an enrichment of numerous biological pathways participating in immunity and neural function. Analysis of the classical HLA alleles and haplotypes showed no genome-wide significant associations. The strongest associations were found for the DQA1*03:01-DQB1*03:02-DRB1*04:01HLA haplotype (P = 4.39 × 10-4, OR = 2.5, 95%CI = 1.499-4.157) and DRB1*04:01 allele (P = 8.3 × 10-5, OR = 2.4, 95%CI = 1.548-3.682) identified in our cohort. As predicted, the CSF proteome showed differential levels of five proteins (HLA-A/B, C4A, ATG4D and NEO1) of expression quantitative trait loci genes from our GWAS in the CSF proteome of anti-GAD65 AINS. These findings suggest a strong genetic predisposition with direct functional implications for immunity and neural function in anti-GAD65 AINS, mainly conferred by genomic regions outside the classical HLA alleles.

Autoantigen characterization in the lower esophageal sphincter muscle of patients with achalasia.

Serum anti-myenteric autoantibodies define autoimmune achalasia and tissue MMP-9 activity may locally process autoantigenic proteins in the muscle of the lower esophageal sphincter (LES) of achalasia patients. Biopsies of the LES muscle from 36 achalasia patients, 6 esophagogastric junction outflow obstruction (EGJOO) patients, and 16 transplant donors (TD) were compared in a blind cross-sectional study. Histological characteristics such as inflammation, fibrosis, presence of ganglion cells, cells of Cajal, GAD65, PNMA2, S-100, P substance, and MMP-9 proteoforms in tissue were assessed by H&E and Picrosirius Red staining and immunohistochemistry analysis. Anti-neuronal antibodies, onconeural antigens, recoverin, SOX-1, titin, zic4, GAD65, and Tr were evaluated by immunoblot/line assay. Tissue of achalasia patients had heterogeneous inflammatory infiltrates with fibrosis and contrasting higher levels of activated MMP-9, as compared with EGJOO and TD. Moreover, lower ganglion cell percentages and cell of Cajal percentages were determined in esophageal tissues of achalasia patients versus TD. The tissues of achalasia versus EGJOO patients had higher GAD65 and PNMA2 protein expression. Unexpectedly, these proteins were absent in TD tissue. S-100 and P substance had similar expression levels in tissues of achalasia patients versus TD and EGJOO. Most of the achalasia sera had anti-GAD65 (83%) and anti-PNMA2 (90%) autoantibodies versus EGJOO (17% and 33%, respectively) and healthy volunteers (10% and 0%, respectively). Tissue-specific ectopic expression of GAD65 and PNMA/Ta2 and active MMP-9, associated with the presence of specific autoantibodies directed against these proteins, might participate in the pathophysiology of achalasia triggering and/or perpetuating autoimmune disease.

Anti-CD20 therapy ameliorates β cell function and rebalances Th17/Treg cells in NOD mice

Anti-CD20 therapy delays type 1 diabetes mellitus (T1DM) progression in both nonobese diabetic (NOD) mice and new-onset patients. The mechanism is not completely defined. This study aimed to investigate the effects of anti-CD20 therapy on T helper 17 (Th17) cells and regulatory T cells (Tregs) in NOD mice. The role of B cell depletion in T1DM development was also examined. NOD mice were randomly divided into two groups. The mice in the experimental group were treated with an anti-CD20 antibody, while the control mice were treated with an isotype-matched control antibody. After treatment, islet morphology and inflammation, Th17 and Treg cell frequencies in the pancreas and spleen, serum cytokine and anti-glutamic acid decarboxylase (GAD) antibody levels, interleukin (IL)-17A levels in the pancreas and spleen, insulin expression in islet cells and islet β cell function were measured. Decreased blood glucose and increased insulin secretion were found in the exprimental group compared with the CON group. A lower islet inflammation score was also found in the experimental group. Decreased Th17 cell and IL-17A levels and augmented Treg cell levels were found in the spleen and pancreas after anti-CD20 treatment. The serum levels of B cell activating factor (BAFF), IL-17A, IL-17F, IL-23 and anti-GAD autoantibodies were decreased in the experimental group, while higher serum levels of IL-10 and transforming growth factor (TGF)-β were found. Anti-CD20 therapy might have some beneficial effects that improve β cell function by relieving islet inflammation through regulation of Th17/Treg cells and the proinflammatory/anti-inflammatory balance.

The early detection of type 1 diabetes mellitus and latent autoimmune diabetes in adults (LADA) through rapid test reverse-flow immunochromatography for glutamic acid decarboxylase 65 kDa (GAD65)

BackgroundDiabetes mellitus (DM) is a chronic and costly disease that has become a primary concern worldwide. Type 1 diabetes mellitus is categorized as an autoimmune disease, which results in islet cell apoptosis and insulin-dependent. GAD65 is known as a potential marker of impaired pancreatic β cell function that appears in the initial phase of type 1 DM and latent autoimmune diabetes in adults (LADA). This study aimed to develop a novel rapid test of anti-GAD65 autoantibodies in human serum samples. MethodsWe have developed a rapid test for anti-GAD65 autoantibodies in this assay based on the reverse-flow immunochromatography method. Human recombinant-protein antigen for GAD65 was attached as the control line over the nitrocellulose membrane. On the other side, the goat anti-mouse immunoglobulin G (IgG) was coated on the same membrane as a control line. The positive result for GAD65 was confirmed by a colloidal gold signal on the strip. Our novel assay analyzed 276 healthy subjects and 51 type 1 diabetes individuals serum samples from several ethnicities in Indonesia for this study. ResultsAmong the 276 healthy samples, 225 samples were identified as positive for anti-GAD65 autoantibodies, while 51 samples were negative. Interestingly, the positive results for anti-GAD65 autoantibodies were linear to the decreasing of high-density lipoprotein (HDL) levels and inversely associated with triglyceride levels. A significant correlation with age was observed in all groups. The sensitivity and specificity test proved that this kit has higher accuracy (AUC value = 0.960). ConclusionThe significant advantages of our rapid test for anti-GAD65 autoantibodies provide higher sensitivity, specificity, and stability compared to previous commercial kits. Therefore, it could be proposed as the future clinical diagnostic kit for patient management of type 1 DM.

Autoimmune Neurogenic Dysphagia.

Autoimmune neurogenic dysphagia refers to manifestation of dysphagia due to autoimmune diseases affecting muscle, neuromuscular junction, nerves, roots, brainstem, or cortex. Dysphagia is either part of the evolving clinical symptomatology of an underlying neurological autoimmunity or occurs as a sole manifestation, acutely or insidiously. This opinion article reviews the autoimmune neurological causes of dysphagia, highlights clinical clues and laboratory testing that facilitate early diagnosis, especially when dysphagia is the presenting symptom, and outlines the most effective immunotherapeutic approaches. Dysphagia is common in inflammatory myopathies, most prominently in inclusion body myositis, and is frequent in myasthenia gravis, occurring early in bulbar-onset disease or during the course of progressive, generalized disease. Acute-onset dysphagia is often seen in Guillain–Barre syndrome variants and slowly progressive dysphagia in paraneoplastic neuropathies highlighted by the presence of specific autoantibodies. The most common causes of CNS autoimmune dysphagia are demyelinating and inflammatory lesions in the brainstem, occurring in patients with multiple sclerosis and neuromyelitis optica spectrum disorders. Less common, but often overlooked, is dysphagia in stiff-person syndrome especially in conjunction with cerebellar ataxia and high anti-GAD autoantibodies, and in gastrointestinal dysmotility syndromes associated with autoantibodies against the ganglionic acetyl-choline receptor. In the setting of many neurological autoimmunities, acute-onset or progressive dysphagia is a potentially treatable condition, requiring increased awareness for prompt diagnosis and early immunotherapy initiation.

Distinct Effects of Stereotactically Injected Human Cerebrospinal Fluid Containing Glutamic Acid Decarboxylase Antibodies into the Hippocampus of Rats on the Development of Spontaneous Epileptic Activity.

Background: The conversion of glutamic acid into γ-aminobutyric acid (GABA) is catalyzed by the glutamic acid decarboxylase (GAD). Antibodies against this enzyme have been described in neurological disorders, but the pathophysiological role of these antibodies is still poorly understood. We hypothesized that anti-GAD autoantibodies could diminish the GABA content in the slice and facilitate epileptic activity. Methods: Cerebrospinal fluids (CSF) from two patients containing anti-GAD (A and B) were injected into the rat hippocampus in vivo. Hippocampal slices were prepared for electrophysiological field potential recordings in order to record recurrent epileptic discharges (REDs) in the CA1 region induced by the removal of Mg2+ and/or by adding gabazine. As control groups, we injected an anti-GAD-negative human CSF or saline solution, and we used non-operated naive animals. Results: RED frequencies were significantly higher in the Mg2+-free solution than in the gabazine-containing solution. The average frequency of REDs in the last 10 min and the average duration of REDs in the last 5 min did not show significant differences between the anti-GAD-B-treated and the control slices, but in the Mg2+-free solution, anti-GAD-A had significantly higher epileptic activity than anti-GAD-B. Conclusions: These results indicate that anti-GAD has distinct effects on the development of spontaneous epileptic activity.

Protein-engineered molecules carrying GAD65 epitopes and targeting CD35 selectively down-modulate disease-associated human B lymphocytes.

Type 1 diabetes mellitus is an autoimmune metabolic disorder characterized by chronic hyperglycemia, the presence of autoreactive T and B cells and autoantibodies against self-antigens. A membrane-bound enzyme on the pancreatic beta-cells, glutamic acid decarboxylase 65 (GAD65), is one of the main autoantigens in type 1 diabetes. Autoantibodies against GAD65 are potentially involved in beta-cell destruction and decline of pancreatic functions. The human complement receptor type 1 (CD35) on B and T lymphocytes has a suppressive activity on these cells. We hypothesized that it may be possible to eliminate GAD65-specific B cells from type 1 diabetes patients by using chimeric molecules, containing an anti-CD35 antibody, coupled to peptides resembling GAD65 B/T epitopes. These molecules are expected to selectively bind the anti-GAD65 specific B cells by the co-cross-linking of the immunoglobulin receptor and CD35 and to deliver a suppressive signal. Two synthetic peptides derived from GAD65 protein (GAD65 epitopes) and anti-CD35 monoclonal antibody were used for the construction of two chimeras. The immunomodulatory activity of the engineered antibodies was tested in vitro using peripheral blood mononuclear cells (PBMCs) from type 1 diabetes patients. A reduction in the number of anti-GAD65 IgG antibody-secreting plasma cells and increased percentage of apoptotic B lymphocytes was observed after treatment of these PBMCs with the engineered antibodies. The constructed chimeric molecules are able to selectively modulate the activity of GAD65-specific B lymphocytes and the production of anti-GAD65 IgG autoantibodies by co-cross-linking of the inhibitory CD35 and the B cell antigen receptor (BCR). This treatment presents a possible way to alter the autoimmune nature of these cells.

Autoimmune diabetes mellitus adult patients having latent autoimmune diabetes of adulthood (LADA) form exhibit different prevalence of accompanying autoimmune diseases than patients with conventional (juvenile) autoimmune type 1 diabetes: Furthermore, anti-GAD autoantibodies are strongly associated with accompanying autoimmune diseases in patients with autoimmune diabetes mellitus

Searchable abstracts of presentations at key conferences in endocrinology ISSN 1470-3947 (print) | ISSN 1479-6848 (online)

Stiff person-syndrome IgG affects presynaptic GABAergic release mechanisms.

The majority of patients with stiff person-syndrome (SPS) are characterized by autoantibodies to glutamate decarboxylase 65 (GAD65). In previous passive-transfer studies, SPS immunoglobulin G (IgG) induced SPS core symptoms. We here provide evidence that SPS-IgG causes a higher frequency of spontaneous vesicle fusions. Sustained GABAergic transmission and presynaptic GABAergic vesicle pool size remained unchanged. Since these findings cannot be attributed to anti-GAD65 autoantibodies alone, we propose that additional autoantibodies with so far undefined antigen specificity might affect presynaptic release mechanisms.

Association of Pediatric Stress Hyperglycemia with Insulin Metabolism Disorders

Introduction: Transient hyperglycemia is a condition that happens during acute physiologic stress in children. The aim of this study is to determine if there is any relation between stress hyperglycemia and diabetes mellitus and metabolic syndrome in pediatric patients. Materials and Methods: The study was performed on children hospitalized in Amirkola pediatric hospital, North of Iran, between February 2011 to January 2013. Children with a history of stress hyperglycemia were studied for the presence of metabolic syndrome or Anti GAD65 Autoantibodies. A total of 50 patients were studied. Results: None of our patients had developed type 1 diabetes. OGTT was normal in all patients. Metabolic syndrome was present in 2 cases (4%). The prevalence of insulin resistance was 16%. The most common metabolic abnormality noted was hypertriglyciredemia and one patient was positive for GAD 65 autoantibody. Conclusion: According to our data children with stress hyperglycemia do not appear to be at increased risk of developing type 1 diabetes but insulin resistance is relatively common in these patients.

The cytokine production of peripheral blood mononuclear cells reflects the autoantibody profile of patients suffering from type 1 diabetes

Event Abstract Back to Event The cytokine production of peripheral blood mononuclear cells reflects the autoantibody profile of patients suffering from type 1 diabetes Jana Labiková1*, Jana Včeláková1, Stanislava Koloušková1 and Kateřina Štechová1 1 Peadiatric Dpt. University Hospital Motol 2nd Medical Faculty, Charles University, Czechia Type 1 diabetes (T1D) is an autoimmune disease characterised by the destruction of pancreatic beta-cells. Proinflammatory Th1 response is considered as the most pathological. Specific autoantibodies can be detected a long time before the disease clinical onset. This study describes the influence of synthetic diabetogenic autoantigens GAD65 and IA2 on the cytokine response of peripheral blood mononuclear cells (PBMC) obtained from T1D patients with regards to their antibody profile. The study has been carried out on T1D patients (n = 40) positive for anti-GAD65 and/or anti-IA2 autoantibodies. Using flow cytometry we measured the cell type ratio in PBMC samples. The cells have been stimulated by three different concentrations of mentioned antigens and their IFN-gamma and IL-17 production has been detected by ELISPOT assay. In the case of both cytokines we have found a significant interaction between the way of stimulation (type and antigen concentration) and the patient's antibody profile (p = 0.003 IFN-gamma; p < 0.001 IL-17). The IA2 autoantibodies level correlates positively with the proportion of Tc cells and negatively with the proportion of Th cells (p = 0.004; p = 0.001). The IFN-gamma production correlates positively with the proportion of T cells and negatively with the proportion of NK cells in PBMC (p = 0.001; p = 0.001). Our results show that patient´s autoantibody profile reflects the type of his/her cellular responses too. This approach can be helpful in designing immunointervention strategies aimed at preventing T1D onset. Such immunointevention should apparently be individualised. Acknowledgements The study was supported by the project (Ministry of Health, Czech Republic) for conceptual development of research organization 00064203 (University Hospital Motol, Prague,Czech Republic), IPL699001 and IGA5240 Keywords: type 1 diabetes, PBMC, GAD65, IA2, IFN-gamma Conference: 15th International Congress of Immunology (ICI), Milan, Italy, 22 Aug - 27 Aug, 2013. Presentation Type: Abstract Topic: Immune-mediated disease pathogenesis Citation: Labiková J, Včeláková J, Koloušková S and Štechová K (2013). The cytokine production of peripheral blood mononuclear cells reflects the autoantibody profile of patients suffering from type 1 diabetes. Front. Immunol. Conference Abstract: 15th International Congress of Immunology (ICI). doi: 10.3389/conf.fimmu.2013.02.00483 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 10 Apr 2013; Published Online: 22 Aug 2013. * Correspondence: Miss. Jana Labiková, Peadiatric Dpt. University Hospital Motol 2nd Medical Faculty, Charles University, Prague, Czechia, jana.labik@seznam.cz Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Jana Labiková Jana Včeláková Stanislava Koloušková Kateřina Štechová Google Jana Labiková Jana Včeláková Stanislava Koloušková Kateřina Štechová Google Scholar Jana Labiková Jana Včeláková Stanislava Koloušková Kateřina Štechová PubMed Jana Labiková Jana Včeláková Stanislava Koloušková Kateřina Štechová Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Human Stiff person syndrome IgG-containing high-titer anti-GAD65 autoantibodies induce motor dysfunction in rats

Stiff person syndrome (SPS) is an autoimmune CNS disorder characterized by muscle rigidity, spasms and anxiety. The majority of patients have high-titer autoantibodies (ab) against glutamate decarboxylase (GAD65). A pathogenic role of SPS-associated IgG with ab against GAD65 has been shown for anxiety-like behavior but not for the core motor signs.We repetitively injected the purified IgG fraction of an SPS patient with severe motor impairment but without anxious comorbidity containing high titers of anti-GAD65 ab (SPS-IgG) into the lateral ventricle (i.c.v.) or intrathecally (i.th.) at the spinal level in experimental rats. We analyzed the effects on motor and anxiety-like behavior. Non-SPS human IgG fractions served as controls.Animals injected i.c.v. with SPS-IgG showed stiffness-like behavior with impaired walking ability and reduced grip strength of the upper limbs as well as postural and sensorimotor dysfunction. Testing for anxiety-like behavior revealed no significant differences between SPS and control IgG-treated rats. IgG deposits were found only in rats treated with SPS-IgG and were localized predominantly in CNS structures involved in motor control including globus pallidus, internal capsule, striatum and anterior thalamus. Double immunofluorescence staining revealed that predominantly GABAergic interneurons were positive for i.c.v. injected SPS-IgG. Rats injected i.th. with SPS-IgG did not present obvious motor symptoms and had a normal synaptic transmission at the spinal level.We conclude that SPS-like motor dysfunction can be induced in rats by passive transfer of IgG from an SPS-patient with high titer of anti-GAD65 ab. GABAergic dysfunction in supraspinal motor pathways rather than in the spinal cord may lead to motor deficits observed in the rats contrasting observations made in SPS with amphiphysin antibodies.