Antibodies against glutamic acid decarboxylase in intravenous immunoglobulin preparations can affect the diagnosis of type 1 diabetes mellitus.

BACKGROUND AND OBJECTIVES: Intravenous immunoglobulins (IVIgs) contain various autoantibodies, including those against glutamic acid decarboxylase (GADAb), a valuable biomarker of type 1 diabetes mellitus. Passive transfer of GADAb from IVIgs to patients poses a risk of misdiagnosis, and information on the specific titres of GADAb and their impact on diagnostic accuracy remains limited. This study aimed to provide further insights into the origin of GADAb detected in patient serum following IVIg infusion. MATERIALS AND METHODS: GADAb titres in IVIg products from Japan and the United States were measured using enzyme-linked immunosorbent assay-based assays. For reliable quantification, GADAb titres in pooled plasma were quantified and compared with those in the IVIg products. The determined titres were used to estimate the likelihood of passively detecting acquired GADAb in individuals receiving IVIgs. RESULTS: GADAbs were prevalent in IVIg products; however, the titres varied significantly among different lots and products. Importantly, IVIg-derived GADAb was estimated to remain detectable in patient serum for up to 100 days following a dosage of 2000 mg/kg. CONCLUSION: Clinicians should consider that IVIg preparations may contain GADAb, which can lead to false-positive results in serological assays. Careful interpretation of the assay results is key to the definitive diagnosis of type 1 diabetes mellitus.

Efgartigimod beyond myasthenia gravis: the role of FcRn-targeting therapies in stiff-person syndrome.

Stiff-person syndrome (SPS) is a rare autoimmune neurological disorder characterized by high titers of antibodies against glutamic acid decarboxylase (GAD) causing impaired GABAergic inhibitory neurotransmission. To date, there is not a defined therapy for such condition, but immunomodulating therapies, such as plasma exchange, intravenous immunoglobulins, and rituximab, have been widely used in clinical practice. However, the efficacy and tolerability of these treatments is not well established. Efgartigimod, a new neonatal Fc receptor (FcRn) blocker, is a human IgG1 antibody Fc fragment engineered with increased affinity for FcRn binding, leading to a reduction in IgGs levels, including pathogenic IgG autoantibody showing promising results in neurological autoimmune disorders and has been approved for the treatment of AChR-seropositive generalized myasthenia gravis (MG). In this study, we report and describe the first data on treatment with efgartigimod in three patients affected by both AChR-seropositive generalized MG and anti-GAD-seropositive SPS. Patients were followed since the start of efgartigimod and for the whole treatment period (12 weeks). MG symptoms were assessed with the "MG activity of daily living score" and the Quantitative Myasthenia Gravis score, while SPS ones were assessed with the "SPS activity of daily living score"; muscle strength was assessed with the Medical Research Council Sum score; the overall disability from MG and SPS was assessed by the modified Rankin Scale. All patients showed an improvement in symptoms of both SPS and MG after 2 cycles of treatment. Our data suggest that efgartigimod may be considered as a candidate drug for SPS and other autoantibody-mediated neurological disorders.

Concomitant Crohn's Disease and Anti-Glutamic Acid Decarboxylase (GAD)-Associated Autoimmune Encephalitis: A Case Report.

Crohn's disease is an inflammatory, autoimmune disorder that predominantly affects the intestines but can also affect extraintestinal organs. Certain neurological conditions, such as autoimmune encephalitis, can develop along with this disease. In this case report, we present a case of anti-glutamic acid decarboxylase (GAD) antibody-associated autoimmune encephalitis that occurred shortly after the diagnosis of Crohn's disease and was unrelated to the treatment and nutritional deficiencies. After a significant weight loss (24 kg) and persistent diarrhea, the patient was diagnosed with Crohn's disease by colonoscopy and biopsy. Within two weeks after the diagnosis, he experienced altered consciousness and memory impairment, followed by a rapid deterioration in consciousness and respiratory distress, leading to intubation and admission to the intensive care unit. His brain MRI revealed asymmetrical diffuse cortical diffusion restrictions, hyperintense signals on fluid-attenuated inversion recovery (FLAIR) sequences, and diffuse pachymeningeal contrast enhancement involving both cingulate gyri, bilateral insular cortices, amygdalae, hippocampi, and the right precuneus. Analysis of cerebrospinal fluid (CSF) revealed a slight elevation of CSF proteins, and the patient tested positive for serum anti-GAD antibodies. The patient responded favorably to a seven-day course of intravenous methylprednisolone, five days of intravenous immunoglobulin (IVIG), and oral corticosteroids. Subsequent treatment consisted of monthly IVIG, azathioprine, and vedolizumab, resulting in no neurologic sequelae except mild amnesia. A follow-up MRI at three months showed a nearly complete disappearance of the lesions. This is the first reported case of anti-GAD-associated encephalitis occurring in the presence of Crohn's disease.

Co-occurrence of Anti-GAD65 Syndrome, Type 1 Diabetes Mellitus, and Focal Seizures With Impaired Awareness.

Glutamic acid decarboxylase (GAD) is an intracellular enzyme found in the presynaptic end of nerve terminals that functions to synthesize ​​gamma-aminobutyric acid (GABA) via decarboxylation. Autoantibodies to the GAD65 isoform have been found in high levels in neurological disorders including stiff person syndrome (SPS), autoimmune encephalitis, and refractory epilepsy. Low levels of anti-GAD65 have also been noted in type 1 diabetes mellitus. We present the unusual case of a woman with a longstanding history of focal seizures with impaired awareness and type 1 diabetes mellitus who was found to have extremely high titers of anti-GAD65 and clinical presentation suggestive of stiff person syndrome. This case highlights the increasing significance of autoimmune etiologies within neurologic disorders, as well as the importance of maintaining a high index of suspicion for rare anti-GAD65 syndromes. Although uncommon and with an unclear pathophysiology, we discuss the importance of establishing SPS diagnostic criteria to facilitate timely diagnosis and quickly direct patient management towards immunotherapy.

Advances in the Pathogenesis of Auto-antibody-Induced Cerebellar Synaptopathies.

The presence of auto-antibodies that target synaptic machinery proteins was documented recently in immune-mediated cerebellar ataxias. The autoantigens include glutamic acid decarboxylase 65 (GAD65), voltage-gated Ca2+ channel (VGCC), metabotropic glutamate receptor type 1 (mGluR1), and glutamate receptor delta (GluRdelta). GAD65 is involved in the synthesis, packaging, and release of GABA, whereas the other three play important roles in the induction of long-term depression (LTD). Thus, the auto-antibodies toward these synaptic molecules likely impair fundamental synaptic machineries involved in unique functions of the cerebellum, potentially leading to the development of cerebellar ataxias (CAs). This concept has been substantiated recently by a series of physiological studies. Anti-GAD65 antibody (Ab) acts on the terminals of inhibitory neurons that suppress GABA release, whereas anti-VGCC, anti-mGluR1, and anti-GluR Abs impair LTD induction. Notably, the mechanisms that link synaptic dysfunction with the manifestations of CAs can be explained by disruption of the "internal models." The latter can be divided into three levels. First, since chained inhibitory neurons shape the output signals through the mechanism of disinhibition/inhibition, impairments of GABA release and LTD distort the conversion process from the "internal model" to the output signals. Second, these antibodies impair the induction of synaptic plasticity, rebound potentiation, and LTD, on Purkinje cells, resulting in loss of restoration and compensation of the distorted "internal models." Finally, the cross-talk between glutamate and microglia/astrocytes could involve a positive feedback loop that accelerates excitotoxicity. This mini-review summarizes the pathophysiological mechanisms and aims to establish the basis of "auto-antibody-induced cerebellar synaptopathies."

L-Asparaginase-Induced Continuous Hyperglycemia With Type 1 Diabetes-Related Antibodies and HLA Genotypes: A Case Study.

A 19-year-old male presented with fatigue and dyspnea on exertion. He was diagnosed with acute T-cell lymphoblastic leukemia. After following the Group for Research on Adult Acute Lymphoblastic Leukemia (GRAALL) 2003 protocol that incorporates L-asparaginase (L-Asp) treatment, blood glucose levels became elevated for more than one year and insulin secretion was depleted. Anti-glutamic acid decarboxylase (GAD) and anti-islet antigen 2 (IA-2) antibody levels were both positive, which is rare. The patient's HLA genotype was sensitive for type 1 diabetes. L-Asp can cause transient hyperglycemia as a side effect. However, cases with the anti-GAD antibody have not been reported in L-Asp-induced diabetes. In summary, L-Asp-induced continuous hyperglycemia might be associated with a type 1 diabetes-related HLA genotype through elevations of anti-GAD and anti-IA-2 antibodies.

Gut Microbiota Functional Traits, Blood pH, and Anti-GAD Antibodies Concur in the Clinical Characterization of T1D at Onset.

Alterations of gut microbiota have been identified before clinical manifestation of type 1 diabetes (T1D). To identify the associations amongst gut microbiome profile, metabolism and disease markers, the 16S rRNA-based microbiota profiling and 1H-NMR metabolomic analysis were performed on stool samples of 52 T1D patients at onset, 17 T1D siblings and 57 healthy subjects (CTRL). Univariate, multivariate analyses and classification models were applied to clinical and -omic integrated datasets. In T1D patients and their siblings, Clostridiales and Dorea were increased and Dialister and Akkermansia were decreased compared to CTRL, while in T1D, Lachnospiraceae were higher and Collinsella was lower, compared to siblings and CTRL. Higher levels of isobutyrate, malonate, Clostridium, Enterobacteriaceae, Clostridiales, Bacteroidales, were associated to T1D compared to CTRL. Patients with higher anti-GAD levels showed low abundances of Roseburia, Faecalibacterium and Alistipes and those with normal blood pH and low serum HbA1c levels showed high levels of purine and pyrimidine intermediates. We detected specific gut microbiota profiles linked to both T1D at the onset and to diabetes familiarity. The presence of specific microbial and metabolic profiles in gut linked to anti-GAD levels and to blood acidosis can be considered as predictive biomarker associated progression and severity of T1D.

Nonocclusive mesenteric ischemia during treatment for ketoacidosis associated with acute-onset type 1 diabetes mellitus: A case report.

This case report describes a patient with nonocclusive mesenteric ischemia that developed due to diabetic ketoacidosis. We believe that early diagnosis and intervention may improve the prognosis of nonocclusive mesenteric ischemia that has low vascular risk, with the major risk factor being dehydration due to diabetic ketoacidosis.

Immunotherapy-responsive Non-paraneoplastic Encephalitis with Antibodies against GAD, LGI1, and GABAA Receptor.

A 62-year-old man showed abnormal behavior. Brain magnetic resonance imaging revealed multifocal lesions on T2-weighted images. Initial screening revealed that he was seropositive for antibodies against glutamate decarboxylase, which usually indicates treatment resistance to autoimmune encephalitis (AE). Intensive immunosuppressive therapies, however, improved the neurological symptoms. In line with this, we also detected seropositivity for antibodies against leucine-rich glioma-inactivated 1 and gamma-aminobutyric acid A receptor (GABAAR). Brain imaging and treatment responsiveness suggested that antibodies against GABAAR were the main cause of symptoms. Furthermore, the patient showed the presence of triple anti-neural antibodies in the absence of malignancy and had a favorable clinical course.

Case Report: Markedly Long-Term Preservation of Pancreatic ß-Cell Function in a Subject With Elderly Onset of Type 1 Diabetes Mellitus Showing High-Titer Autoimmune Antibodies for Over 4 Years.

Type 1 diabetes mellitus (T1DM) is mainly triggered by autoimmune ß-cell destruction, usually leading to absolute insulin deficiency. Regarding the speed of ß-cell destruction, there are large variations depending on age. In some adult cases, sufficient ß-cell function is sometimes retained for a relatively long period and eventually they become dependent on insulin for survival. It is known that even in subjects with T1DM showing high titers of such antibodies, insulin secretory capacity is preserved under several conditions such as "honeymoon" period and slowly progressive T1DM (SPIDDM). Herein, we reported the acute onset T1DM subject with long-term preservation of ß-cell function, although his anti-GAD antibody and anti-IA-2 antibody titers were very high for more than 4 years. This case is very important in that his ß-cell function was preserved with dipeptidyl peptidase-4 inhibitor alone. This means that there are large variations in the speed of ß-cell destruction in the onset of T1DM.

A Case Report of Latent Autoimmune Diabetes Arising After Isotretinoin Treatment: Real Association or Coincidence? A Hypothesis on Pathophysiology.

BACKGROUND: Latent autoimmune diabetes in adults (LADA) is the most common form of adult-onset autoimmune diabetes. Isotretinoin is a very effective treatment for severe acne. There are various reports on the effect of isotretinoin on autoimmunity. We present a case of LADA, probably related to isotretinoin treatment. To the best of our knowledge, this case was the second case of LADA that occurred after isotretinoin treatment. Here we discuss a hypothesis on the pathophysiology of how isotretinoin can induce LADA. CASE PRESENTATION: A 55-year-old female was diagnosed with type 2 diabetes mellitus (T2DM) one month after the end of a nine-month isotretinoin treatment period. At the time of diagnosis, the patient's fasting blood glucose level was 257 mg/dL and HbA1c level was 10.3%. Then, she was followed-up for T2DM for two years. Since the patient did not comply with classical T2DM characteristics and C-peptide level was 0.4 ng/ml (0.78-5.18), autoantibody test was performed. The patient was found positive for anti-glutamic acid decarboxylase antibody (>2000 IU/mL). Her oral antidiabetic drug treatment was discontinued and insulin degludec and insulin aspart therapy was started. Three months after this adjustment, HbA1c level decreased to 7.2%. Except 25-hydroxycholecalciferol which was low (10.9 ng/mL), all other laboratory parameters were within normal range. CONCLUSION: Isotretinoin is known to have some immunomodulating effects. There are some case reports on the relationship between isotretinoin and autoimmune diseases. The negative immune environment that developed due to the long-standing moderate-severe VitD deficiency may have taken a turn toward autoimmunity upon isotretinoin treatment. This hypothesis on how isotretinoin can cause autoimmune diabetes needs to be validated.

Glutamic acid decarboxylase 65-positive autoimmune encephalitis presenting with gelastic seizure, responsive to steroid: A case report.

BACKGROUND: Anti-glutamic acid decarboxylase (GAD) antibody is known to cause several autoimmune-related situations. The most known relationship is that it may cause type I diabetes. In addition, it was also reported to result in several neurologic syndromes including stiff person syndrome, cerebellar ataxia, and autoimmune encephalitis. Decades ago, isolated epilepsy associated with anti-GAD antibody was first reported. Recently, the association between temporal lobe epilepsy and anti-GAD antibody has been discussed. Currently, with improvements in examination technique, many more autoimmune-related disorders can be diagnosed and treated easier than in the past. CASE SUMMARY: A 44-year-old female Asian with a history of end-stage renal disease (without diabetes mellitus) under hemodialysis presented with diffuse abdominal pain. The initial diagnosis was peritonitis complicated with sepsis and paralytic ileus. Her peritonitis was treated and she recovered well, but seizure attack was noticed during hospitalization. The clinical impression was gelastic seizure with the presentation of frequent smiling, head turned to the right side, and eyes staring without focus; the duration was about 5-10 s. Temporal lobe epilepsy was recorded through electroencephalogram, and she was later diagnosed with anti-GAD65 antibody positive autoimmune encephalitis. Her seizure was treated initially with several anticonvulsants but with poor response. However, she showed excellent response to intravenous methylprednisolone pulse therapy. Her consciousness returned to normal, and no more seizures were recorded after 5 d of intravenous methylprednisolone treatment. CONCLUSION: In any case presenting with new-onset epilepsy, in addition to performing routine brain imaging to exclude structural lesion and cerebrospinal fluid studies to exclude common etiologies of infection and inflammation, checking the autoimmune profile has to be considered. In the practice of modern medicine, autoimmune-related disorders are relatively treatable and should not be missed.

Effectiveness of Combined Immunoglobulin and Glucocorticoid Treatments in a Patient With Stiff Limb Syndrome: Case Report and Review of the Literature.

Stiff limb syndrome (SLS) is a rare autoimmune-related central nervous system disorder, resulting in stiffness and spasms of limbs since onset with rare involvement of the truncal muscles. However, SLS patients will gain notable effects by appropriate therapy focusing on symptomatic treatment and immunotherapy. We reported on a 55-year-old female who showed typical painful spasms in both lower limbs and abduction of the right eyeball that partially responded to low-dose diazepam and had high-titer anti-glutamic acid decarboxylase (anti-GAD) antibody. Electromyography (EMG) only showed continuous motor unit activity (CMUA) in the anterior tibialis and right triceps. Eventually, our patient was diagnosed with SLS and treated with intravenous immunoglobulin (IVIG) and glucocorticoid combined simultaneously. She obtained notable effects. We also review and summarize the current literature on clinical characteristics, coexisting disease, treatment, and outcome of 40 patients with SLS. We hope that this report will provide a basis for further understanding of SLS and promote the formation of more advanced diagnosis and treatment processes.

Anti-GAD epileptic encephalopathy in a toddler with Parry-Romberg syndrome.

Parry-Romberg syndrome (PRS) is a progressive facial hemiatrophy often associated with severe epilepsy. Although an immune-mediated vasculitic pathogenesis is widely assumed, no CNS-specific autoantibody has been described so far. A 2-year-old boy was admitted for a status epilepticus preceded by fever, restlessness, insomnia, and left facial rash. Cerebrospinal fluid was positive for glutamic acid decarboxylase (GAD)-antibodies. Brain MRI revealed FLAIR hyperintensities on left mediotemporal areas. He was successfully treated with intravenous methylprednisolone. One month later, seizures and facial rash reappeared and steroids were satisfactorily repeated. However, left hemifacial rash reappeared 5 months later, slowly followed by sclerotic skin lesions on frontal scalp and hemifacial sub-atrophy, leading to a diagnosis of PRS. Three years later, and despite chronic immunosuppression, new MRI lesions on left white matter are seen and left hemifacial atrophy has progressed. For the first time, we describe GAD autoantibodies in a PRS patient with epileptic encephalopathy. Epileptic syndromes with GAD autoantibodies are frequently described though with a questionable pathogenic significance. Given the clinical and MRI similarities of PRS with both Morphea and Rasmussen's encephalitis, we suggest that, in our patient, the initial facial skin vasculitis spread into CNS vessels through perforating arteries, inducing neuronal MHC-class I presentation of GAD epitopes, ultimately causing CD8-mediated neuronal cytotoxicity and the epileptic encephalopathy. GAD autoantibodies might represent the missing pathophysiological link between PRS and neuropsychiatric manifestations.

Immune Mediated Cerebellar Ataxia: An Unknown Manifestation of Graft-versus-Host Disease.

Neurologic complications of allogeneic hematopoietic cell transplantation (allo-HCT) include infections, cerebrovascular events, therapy-induced neurotoxicity, recurrent malignancies, and neurologic manifestations of graft-versus-host disease (GVHD). Anti-glutamic acid decarboxylase (GAD) antibody-associated cerebellar ataxia is a well-established disorder of autoimmune origin, but there are no reports in the literature of its occurrence following allo-HCT. We describe a middle-aged woman with chronic GVHD after allo-HCT who presented with a rapidly progressive cerebellar syndrome. Thorough investigation revealed only cerebellar atrophy on brain imaging and positive anti-GAD65 antibodies in serum and cerebrospinal fluid suggesting the diagnosis of anti-GAD antibody-associated cerebellar ataxia. Despite prompt treatment with high-dose corticosteroids, intravenous immunoglobulins, and rituximab, the patient's condition rapidly deteriorated, and she died 4 months later. This case suggests that anti-GAD antibody-associated cerebellar ataxia may be a rare manifestation of chronic GVHD.

Stiff person syndrome: An unusual paraneoplastic neurological phenomenon in Carcinoid tumour

@#Stiff person syndrome is a rare neurologic disorder characterised by rigidity of the truncal and proximal limb muscles with intermittent superimposed spasms. It’s unique because it lacks similarity to any other neurologic disorder. Possibly tetanus is the closest related condition with both inhibiting central gamma-aminobutyric (GABA) systems. Stiff person syndrome is extremely rare with less than 20 cases reported from South Asia which has a population of nearly 2 billion. In its classic form, it is associated with the presence of high titres of glutamic acid decarboxylase (GAD) antibodies. Paraneoplastic stiff person syndrome comprising of around 5% of the patients has been reported with malignancies of the breast, colon, lung, thymus and Hodgkin’s lymphoma. Antibodies against amphiphysin and gephyrin are detected in paraneoplastic stiff person syndrome. We report a 58 year old Sri Lankan male with stiff person syndrome with a high GAD antibody titre and classical electromyographic changes, who was found to have an underlying carcinoid tumour. We postulate that stiff person syndrome was a paraneoplastic phenomenon secondary to the carcinoid in this case. Although neurological syndromes such as sensory neuropathy, limbic encephalitis and, myelopathy have been described as paraneoplastic features in carcinoid, we believe this is the first report of stiff person syndrome associated with carcinoid tumour.

Refractory epilepsy secondary to anti-GAD encephalitis treated with DBS post SEEG evaluation: a novel case report based on stimulation findings.

We report a case of medically refractory anti-GAD encephalitis which was treated with deep brain stimulation (DBS) after seizure termination was achieved using cortical stimulation during stereo-electroencephalography (SEEG) evaluation. The patient underwent bilateral SEEG implantation and cortical stimulation. Upon stimulation, mimicking the intrinsic seizures (at 1 Hz), it was possible to induce seizures with typical semiology, on multiple attempts. Stimulation during these seizures with high frequency (50 Hz) resulted in complete termination of the seizure. DBS was inserted after the SEEG evaluation, targeting the bilateral anterior nucleus of the thalamus. There was a sustained reduction in seizure frequency and severity 12 months post insertion. There were also improvements in quality of life. To the best of our knowledge, this is the only case reported in which DBS was successfully used to treat refractory epilepsy in a patient with seizures that were proven to be responsive to electrical stimulation during SEEG recording.

Neurologic disorders associated with anti-glutamic acid decarboxylase antibodies: A comparison of anti-GAD antibody titers and time-dependent changes between neurologic disease and type I diabetes mellitus.

To determine clinical features of neurologic disorders associated with anti-glutamic acid decarboxylase antibodies (anti-GAD-Ab), we examined titers and time-dependent changes of anti-GAD-Ab. Six patients, stiff person syndrome (2), cerebellar ataxia (1), limbic encephalitis (1), epilepsy (1), brainstem encephalitis (1), were compared with 87 type I diabetes mellitus (T1DM) patients without neurologic disorders. Anti-GAD-Ab titers and index were higher in neurologic disorders than in T1DM, suggesting intrathecal antibody synthesis. Anti-GAD-Ab titers in T1DM decreased over time, whereas they remained high in neurologic disorders. Immunotherapy improved neurological disorders and anti-GAD-Ab titers and index provide clinically meaningful information about their diagnostic accuracy.

Prevalence of double diabetes in youth onset diabetes patients from east Delhi and neighboring NCR region.

BACKGROUND: It is being increasingly reported that some of the youth onset diabetes patients cannot be classified clearly as type 1 diabetes mellitus (T1DM) or type 2 diabetes mellitus (T2DM) based on usual criteria and the term double diabetes (DD) coined for these cases. AIM: The objective of the study was to find out the prevalence of DD in youth onset diabetes patients from east Delhi and neighboring NCR region. METHODS: A total of 200 patients with youth onset diabetes below 25 years of age were recruited from a tertiary care hospital in East Delhi. Clinical history, family history of diabetes and anthropometry of patients were recorded. Fasting serum C-peptide, Anti-IA2-antibody and Anti-GAD-antibody were measured in all patients. Patients positive for Anti-GAD-antibody (>1.05U/ml) and C-peptide level >0.3nmol/l were characterized as DD patients. Patients negative for Anti-GAD-antibody and C-peptide >0.3nmol/l were kept under the category of T2DM. Patients with low C-peptide level along with one of the following, positive Anti-GAD-antibody, positive Anti-IA2-antibody and diabetic ketoacidosis (DKA) were considered as T1DM. Remaining patients were kept under the unknown category. RESULTS: Mean age of study subjects was 18.2±7.1years. Seven percent (7%) of the subjects were classified as DD, 51% as T1DM, 13% as T2DM and 29% were kept under the unknown category. Mean age of subjects with 22.2±9.7, 16.9±6.7, 20.6±7.7 and 19.4±7.4 years in DD, T1DM, T2DM and unknown category respectively. Mean BMI of subjects with DD, T1DM, T2DM and unknown category was 19.8±5.7, 16.6±3.7, 19.3±4.1 and 18.0±4.6 kg/m2 respectively. CONCLUSION: Double diabetes is an important occurrence among youth onset diabetes subjects. Only half of the subjects with youth onset of diabetes had T1DM.

Refractory status epilepticus and glutamic acid decarboxylase antibodies in adults: presentation, treatment and outcomes.

Glutamic acid decarboxylase antibodies (GAD-Abs) have been implicated in refractory epilepsy. The association with refractory status epilepticus in adults has been rarely described. We discuss our experience in managing three adult patients who presented with refractory status epilepticus associated with GAD-Abs. Case series with retrospective chart and literature review. Three patients without pre-existing epilepsy who presented to our institution with generalized seizures between 2013 and 2014 were identified. Seizures proved refractory to first and second-line therapies and persisted beyond 24 hours. Patient 1 was a 22-year-old female who had elevated serum GAD-Ab titres at 0.49 mmol/l (normal: <0.02) and was treated with multiple immuno- and chemotherapies, with eventual partial seizure control. Patient 2 was a 61-year-old black female whose serum GAD-Ab titre was 0.08 mmol/l. EEG showed persistent generalized periodic discharges despite maximized therapy with anticonvulsants but no immunotherapy, resulting in withdrawal of care and discharge to nursing home. Patient 3 was a 50-year-old black female whose serum GAD-Ab titre was 0.08 mmol/l, and was discovered to have pulmonary sarcoidosis. Treatment with steroids and intravenous immunoglobulin resulted in seizure resolution. Due to the responsiveness to immunotherapy, there may be an association between GAD-Abs and refractory seizures, including refractory status epilepticus. Causation cannot be established since GAD-Abs may be elevated secondary to concurrent autoimmune diseases or formed de novo in response to GAD antigen exposure by neuronal injury. Based on this report and available literature, there may be a role for immuno- and chemotherapy in the management of refractory status epilepticus associated with GAD-Abs.