No association of anti-GM1 and anti-GAD antibodies with juvenile myoclonic epilepsy: A pilot study

Neuronal antibodies in adult patients with new-onset seizures: A prospective study

OBJECTIVES

Immunotherapy in addition to antiepileptic drugs can improve seizure freedom rates in autoimmune epilepsy, highlighting the importance of early diagnosis. A diagnosis of autoimmune epilepsy can be supported by presence of serum antibodies to neuronal antigens. We asked how often neuronal antibodies are found in the serum of unselected adult patients with new-onset seizures and whether such testing could improve detection of autoimmune epilepsy.

MATERIAL AND METHODS

We included 44 patients over the age of 25 presenting after at least one unprovoked seizure to the Neurology Clinic at Sahlgrenska University Hospital, Gothenburg, Sweden. The median time between the first-ever seizure in life and the serum sampling was 50 days (range 22-11,000). Antibody testing in serum was performed according to the manufacturer's instructions. The patients were followed for at least 1 year.

RESULTS

Epilepsy could be diagnosed already at the first visit in 21/44 patients (47.7%). Two patients (4.5%) were positive for neuronal antibodies: one against contactin-associated protein 2 (CASPR-2) and one against glutamate acid decarboxylase (GAD). Three patients (6.7%) displayed very weak immunoreactivity that was deemed clinically insignificant. One of the antibody-positive patients had only a single seizure. The other had a focal cortical dysplasia and was seizure-free on levetiracetam. None of the five patients with antibodies or immunoreactivity displayed any feature of autoimmune epilepsy.

CONCLUSIONS

We conclude that indiscriminate testing in patients presenting to a first seizure clinic with new-onset seizures or epilepsy is unlikely to improve detection of autoimmune epilepsy.

Antiglutamic acid decarboxylase 65 (GAD65) antibody-associated epilepsy

Glutamic acid decarboxylase (GAD) antibody-associated encephalitis causes both acute seizures and chronic epilepsy with predominantly temporal lobe onset. This condition is challenging in diagnosis and management, and the incidence of GAD antibody (Ab)-related epilepsy could be much higher than commonly believed. Imaging and CSF evidence of inflammation along with typical clinical presentations, such as adult onset temporal lobe epilepsy (TLE) with unexplained etiology, should prompt testing for the diagnostic antibodies. High serum GAD Ab titer (≥2000U/mL or ≥20nmol/L) and evidence of intrathecal anti-GAD Ab synthesis support the diagnosis. Unlike other immune-mediated epilepsies, antiglutamic acid decarboxylase 65 (GAD65) antibody-mediated epilepsy is often poorly responsive to antiepileptic drugs (AEDs) and only moderately responsive to immune therapy with steroids, intravenous immunoglobulin (IVIG), or plasma exchange (PLEX). Long-term treatment with more aggressive immunosuppressants such as rituximab (RTX) and/or cyclophosphamide is often necessary and may be more effective than current immunosuppressive approaches. The aim of this review is to review the physiology, pathology, clinical presentation, related ancillary tests, and management of GAD Ab-associated autoimmune epilepsy by searching the keywords and to promote the recognition and the initiation of proper therapy for this condition.

Evaluation of Glutamic Acid Decarboxylase Antibody Levels in Patients with Juvenile Myoclonic Epilepsy and Mesial Temporal Lobe Epilepsy with Hippocampal Sclerosis

INTRODUCTION

Several clinical studies have been conducted to investigate the role of autoantibodies and immunological mechanisms in the etiology of treatment-resistant epilepsy in recent years. Some immunological treatments have been suggested as a result of these studies. In this study, we aimed to investigate the role of autoimmunity in partial and idiopathic generalized epilepsy and determine the relationship between drug resistance and autoimmune antibodies.

METHODS

Twenty-eight patients (24 treatment-responsive and 4 treatment-resistant) with juvenile myoclonic epilepsy (JME), 26 patients with mesial temporal lobe epilepsy with hippocampal sclerosis (MTLEHS) resistant to antiepileptic drug treatment, and 26 age-matched healthy control subjects were included in a two-year cross sectional study. Glutamic acid decarboxylase antibody (GADA) levels were measured with a radioimmunoassay method in the serum of the included subjects.

RESULTS

High GADA titers were detected in 2 patients with JME (7.1%), 1 patient with MTLEHS (3.8%), and 1 healthy subject (3.8%). There was no statistically significant difference among the groups regarding the serum GADA level. Although a limited number of drug-resistant patients with JME our study did not show relationships among anti-GADAs, both epileptic syndromes and drug resistance.

CONCLUSION

Because we did not determine any significant relationship between GADA levels and JME or MTLEHS, we do not recommend analysis of serum GADA levels in routine examinations where there is no evidence to suggest risk factors for autoimmunity.

Immunity and Inflammation in Epilepsy

This review reports the available evidence on the activation of the innate and adaptive branches of the immune system and the related inflammatory processes in epileptic disorders and the putative pathogenic role of inflammatory processes developing in the brain, as indicated by evidence from experimental and clinical research. Indeed, there is increasing knowledge supporting a role of specific inflammatory mediators and immune cells in the generation and recurrence of epileptic seizures, as well as in the associated neuropathology and comorbidities. Major challenges in this field remain: a better understanding of the key inflammatory pathogenic pathways activated in chronic epilepsy and during epileptogenesis, and how to counteract them efficiently without altering the homeostatic tissue repair function of inflammation. The relevance of this information for developing novel therapies will be highlighted.

Investigation of neuronal autoantibodies in two different focal epilepsy syndromes

OBJECTIVE

Neuronal antibodies have been identified in patients with seizures as the main or sole symptom. Our aim was to investigate the prevalence of these autoantibodies in patients with focal epilepsy of unknown cause (FEoUC) and in the group having mesial temporal lobe epilepsy with hippocampal sclerosis (MTLE-HS).

METHODS

We studied anti-neuronal antibodies of consecutive adult patients diagnosed with FEoUC and MTLE-HS in our epilepsy center. The clinical and laboratory features of antibody-positive patients were compared with those of seronegative patients. The responses to therapy have also been investigated.

RESULTS

Sera from 81 patients with epilepsy were tested. We found antibodies against glycine receptor (GLY-R) in 5 (6.2%), contactin-associated protein 2 (CASPR-2) in 4 (4.9%), N-methyl-d-aspartate receptor (NMDA-R) in 2 (2.5%), and voltage-gated potassium channel (VGKC)-complex in 2 (2.5%) of our patients with epilepsy. Psychotic attacks and nonspecific magnetic resonance imaging (MRI) white matter changes (WMCs) showed significant associations in seropositive patients (p = 0.003 and p = 0.03, respectively). Poor drug-response rates and total seizure counts were also higher in the seropositive patients but without reaching statistical significance. Three seropositive patients with previous epilepsy surgery showed typical histopathologic results for MTLE-HS, but not inflammatory changes. Moreover, some patients harboring these antibodies partly benefited from immunotherapy.

SIGNIFICANCE

We detected neuronal antibodies in one sixth of patients with focal epilepsy, GLY-R antibodies being the leading one. Psychosis or nonspecific MRI WMCs were frequent in the seropositive group. Our results suggested that relevant antibodies should be screened for a treatment possibility in these groups.

Temporal lobe epilepsy and anti glutamic acid decarboxylase autoimmunity

Epilepsy is one of the most impactful diseases on social life. A significant number of epileptic syndromes have been linked to immunological alterations. Elevated levels of antibodies against glutamic acid decarboxylase have been recently found in a significant percentage of patients with temporal lobe epilepsy, the most common epilepsy type. The clinical and pathogenetic relationship of this association is discussed. This link may have important therapeutic implications and merits additional clinical and laboratory research.

The growing recognition of immunotherapy-responsive seizure disorders with autoantibodies to specific neuronal proteins

PURPOSE OF REVIEW

The concept of epilepsy and seizure disorders caused by autoantibodies to specific neuronal membrane proteins has developed significantly during the past few years.

RECENT FINDINGS

Antibodies to cell-surface membrane proteins such as voltage-gated potassium channels or N-methyl-D-aspartate receptors, or to glutamic acid decarboxylase, are found in patients with different forms of limbic encephalitis, and in a few patients with epilepsy as their main or only condition. Many of these patients do not show a good response to conventional antiepileptic drugs, but respond to immunotherapies. By contrast, studies of other antibodies in idiopathic forms of epilepsy, or epilepsy associated with systemic lupus erythematosus or coeliac disease, have not in general disclosed consistent, clinically helpful results.

SUMMARY

There are a growing number of specific antibodies associated with new onset epilepsy. These patients are likely to have an immune-mediated disorder that may benefit from immunotherapies. In autoimmune diseases such as systemic lupus erythematosus or coeliac disease, antibodies to specific membrane targets may also prove to be important in the future.