Epilepsy and the immune system: is there a link?

The Concept of an Epilepsy Brain Bank

Epilepsy comprises more than 40 clinical syndromes affecting millions of patients and families worldwide. To decode the molecular and pathological framework of epilepsy researchers, need reliable human epilepsy and control brain samples. Brain bank organizations collecting and supplying well-documented clinically and pathophysiologically tissue specimens are important for high-quality neurophysiology and neuropharmacology studies for epilepsy and other neurological diseases. New development in molecular mechanism and new treatment methods for neurological disorders have evoked increased demands for human brain tissue. An epilepsy brain bank is a storage source for both the frozen samples as well as the formaldehyde fixed paraffin embedded (FFPE) tissue from epilepsy surgery resections. In 2014, the University of Saskatchewan have started collecting human epilepsy brain tissues for the first time in Canada. This review highlights the necessity and importance of Epilepsy Brain bank that provides unique access for research to valuable source of brain tissue and blood samples from epilepsy patients.

Intravenous immunoglobulins for epilepsy

BACKGROUND

Epilepsy is a common neurological condition, with an estimated incidence of 50 per 100,000 persons. People with epilepsy may present with various types of immunological abnormalities, such as low serum immunoglobulin A (IgA) levels, lack of the immunoglobulin G (IgG) subclass and identification of certain types of antibodies. Intravenous immunoglobulin (IVIg) treatment may represent a valuable approach and its efficacy has important implications for epilepsy management. This is an update of a Cochrane review first published in 2011 and last updated in 2017.

OBJECTIVES

To examine the effects of IVIg on the frequency and duration of seizures, quality of life and adverse effects when used as monotherapy or as add-on treatment for people with epilepsy.

SEARCH METHODS

For the latest update, we searched the Cochrane Register of Studies (CRS Web) (20 December 2018), MEDLINE (Ovid, 1946 to 20 December 2018), Web of Science (1898 to 20 December 2018), ISRCTN registry (20 December 2018), WHO International Clinical Trials Registry Platform (ICTRP, 20 December 2018), the US National Institutes of Health ClinicalTrials.gov (20 December 2018), and reference lists of articles.

SELECTION CRITERIA

Randomised or quasi-randomised controlled trials of IVIg as monotherapy or add-on treatment in people with epilepsy.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed the trials for inclusion and extracted data. We contacted study authors for additional information. Outcomes included percentage of people rendered seizure-free, 50% or greater reduction in seizure frequency, adverse effects, treatment withdrawal and quality of life.

MAIN RESULTS

We included one study (61 participants). The included study was a randomised, double-blind, placebo-controlled, multicentre trial which compared the treatment efficacy of IVIg as an add-on with a placebo add-on in patients with drug-resistant epilepsy. Seizure freedom was not reported in the study. There was no significant difference between IVIg and placebo in 50% or greater reduction in seizure frequency (RR 1.89, 95% CI 0.85 to 4.21; one study, 58 participants; low-certainty evidence). The study reported a statistically significant effect for global assessment in favour of IVIg (RR 3.29, 95% CI 1.13 to 9.57; one study, 60 participants; low-certainty evidence). No adverse effects were demonstrated. We found no randomised controlled trials that investigated the effects of IVIg monotherapy for epilepsy. Overall, the included study was rated at low to unclear risk of bias. Using GRADE methodology, the certainty of the evidence was rated as low.

AUTHORS' CONCLUSIONS

We cannot draw any reliable conclusions regarding the efficacy of IVIg as a treatment for epilepsy. Further randomised controlled trials are needed.

Intravenous immunoglobulins for epilepsy

BACKGROUND

Epilepsy is a common neurological condition, with an estimated incidence of 50 per 100,000 persons. People with epilepsy may present with various types of immunological abnormalities, such as low serum immunoglobulin A (IgA) levels, lack of the immunoglobulin G (IgG) subclass and identification of certain types of antibodies. Intravenous immunoglobulin (IVIg) treatment may represent a valuable approach and its efficacy has important implications for epilepsy management. This is an updated version of the original Cochrane review published in Issue 1, 2011.

OBJECTIVES

To examine the effects of IVIg on the frequency and duration of seizures, quality of life and adverse effects when used as monotherapy or as add-on treatment for people with epilepsy.

SEARCH METHODS

For the latest update, we searched the Cochrane Epilepsy Group Specialized Register (2 February 2017), the Cochrane Central Register of Controlled Trials (CENTRAL) via the Cochrane Register of Studies Online (2 February 2017), MEDLINE (Ovid, 1946 to 2 February 2017), Web of Science (1898 to 2 February 2017), ISRCTN registry (2 February 2017), WHO International Clinical Trials Registry Platform (ICTRP, 2 February 2017), the US National Institutes of Health ClinicalTrials.gov (2 February 2017), and reference lists of articles.

SELECTION CRITERIA

Randomized or quasi-randomized controlled trials of IVIg as monotherapy or add-on treatment in people with epilepsy.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed the trials for inclusion and extracted data. We contacted study authors for additional information. Outcomes included percentage of people rendered seizure-free, 50% or greater reduction in seizure frequency, adverse effects, treatment withdrawal and quality of life.

MAIN RESULTS

We included one study (61 participants). The included study was a randomized, double-blind, placebo-controlled, multi-centre trial which compared the treatment efficacy of IVIg as an add-on with a placebo add-on in patients with refractory epilepsy. There was no significant difference between IVIg and placebo in 50% or greater reduction in seizure frequency. The study reported a statistically significant effect for global assessment in favour of IVIg. No adverse effects were demonstrated. We found no randomized controlled trials that investigated the effects of IVIg monotherapy for epilepsy. Overall, the included study was rated as low/unclear risk of bias. Using GRADE methodology, the quality of the evidence was rated as low.

AUTHORS' CONCLUSIONS

We cannot draw any reliable conclusions regarding the efficacy of IVIg as a treatment for epilepsy. Further randomized controlled trials are needed.

The role of IL-1β and glutamate in the effects of lipopolysaccharide on the hippocampal electrical kindling of seizures

In our study, we used rapid electrical hippocampal kindling and in vivo microdialysis methods to assess the involvement of inflammatory mediators: lipopolysaccharide (LPS) and proinflammatory interleukin-1β (IL-1β) in mechanisms of epileptogenesis. We observed, that both, LPS and IL-1β, administered into stimulated hippocampus, accelerated kindling process. LPS also increased the expression of IL-1β in stimulated hippocampus in kindled rats. In vivo acute LPS perfusion, via a microdialysis cannula implanted into the naïve rat's hippocampus, produced an increase in extracellular glutamate release. We suppose, that particularly IL-1β action and increased glutamate concentration may significantly contribute to LPS effects on kindling development.

Viscum Album in the Treatment of a Girl With Refractory Childhood Absence Epilepsy

Viscum album (European mistletoe) extracts have known immunomodulatory effects but little data exist on anticonvulsant activity despite its usefulness having been reported for centuries. A 4½-year-old girl with childhood absence epilepsy and global developmental delay was treated with different antiepileptic drugs and ketogenic diet but failed to become seizure free over a 2-year period. She also received different herbal remedies as part of an integrative medicine approach. Initial improvement occurred on valproate-ethosuximide, a further improvement was seen after adding clobazam to valproate. Final cessation of absence activity occurred after a dose increase of V album. She was still seizure free at the 12-month follow-up. V album appears to have been a necessary adjunct treatment for this child to become seizure free. We call on physicians to report their experiences of V album in epilepsy and suggest further study.

Immunomodulation in Adult Epilepsy: The Role of IVIG

Much of the research for intravenous immunoglobulins (IVIG) use in epilepsy has focused on childhood epilepsies and the results have been inconclusive. As evidence for inflammation in epilepsy and epileptogenesis is accumulating, IVIG might have a role to play in adult epilepsy. Our literature review focuses on the purported mechanisms of IVIG, the link between inflammation and the various causes of adult epilepsy and the different steps of epileptogenesis at which inflammation might play a role. We also review the current clinical evidence supporting IVIG as a treatment for epilepsy in the adult population. Though there is interesting theoretical potential for treatment of refractory epilepsy in adults with IVIG, insufficient evidence exists to support its standard use. The question remains if IVIG should still be considered as an end-of-the-line option for patients with epilepsy poorly responsive to all other treatments.

Tumor necrosis factor-α and interleukin-6 concentrations in cerebrospinal fluid of dogs after seizures

BACKGROUND

Idiopathic and acquired epilepsy are common in dogs. Up to 30% of these dogs are refractory to pharmacological treatment. Accumulating experimental evidence indicates that brain immune response and presence of inflammatory mediators decrease the threshold for individual seizures and contribute to epileptogenesis.

HYPOTHESIS

Dogs with seizures have higher cerebrospinal interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) concentrations compared to dogs with no seizures.

METHODS

A prospective double blinded study; cerebrospinal fluid (CSF) and serum IL-6, TNF-α and total protein (TP) concentrations were measured by a blinded investigator for the study group and CSF IL-6 and TNF-α levels and TP concentrations were measured in the control group (CG).

ANIMALS

Dogs presented with seizures that had enough CSF collected to allow analysis were included in the study group. Twelve apparently healthy, quarantined, stray dogs served as control (CG).

RESULTS

Cerebrospinal fluid TNF-α and IL-6 concentrations were significantly higher (P = .011, P = .039) in dogs with seizures (0 ± 70.66, 0.65 ± 10.93 pg/mL) compared to the CG (0 ± 19, 0.73 ± 0.55 pg/mL). When assessing cytokine concentrations of specifically the idiopathic epilepsy (IE) dogs compared to the CG, only TNF-α concentrations (8.66 ± 62, 0 ± 19 pg/mL) were significantly higher (P = .01). CSF TP concentrations were not significantly higher in the study dogs compared to the CG.

CONCLUSIONS AND CLINICAL IMPORTANCE

Higher TNF-α and IL-6 concentration in the CSF of dogs with naturally occurring seizures. The higher supports the hypothesis that inflammatory processes through certain mediators play a role in the pathogenesis of seizures in dogs.

Generalized epilepsies: immunologic and inflammatory mechanisms

This article focuses on the inflammatory processes in patients with generalized epilepsies. We specifically review the data regarding West, Lennox-Gastaut, and Landau-Kleffner syndromes as they have generalized clinical or electroencephalogram features. There is substantial evidence for a pathogenic implication of immune mechanisms in these epilepsies. Animal models and abnormalities in both cellular and humoral immunity support this hypothesis. They also appear to be particularly responsive to immunomodulatory therapies, which has raised the speculation that an unbalanced immune system may play an important role in the pathophysiology of these epileptic syndromes. In this article, we discuss clinical and experimental data that support the potential implication of immune mediated inflammation and immune response in the mechanism of these entities.

Seizure freedom after lamotrigine rash: a peculiar phenomenon in epilepsy

A 57-year-old right-handed woman with a history of left frontal lobe stroke had experienced episodes of language-expression difficulty followed by paraphasia lasting for approximately 30 seconds two years earlier. She was diagnosed with left frontal lobe epilepsy, and a lamotrigine regimen was initiated. This treatment had to be stopped five weeks after initiation because she developed a rash, and her drug lymphocyte stimulation test result was positive. Interestingly, she has since remained seizure free without requiring any antiepileptic medications. This adult case with a peculiar clinical course provides support for the hypothesis of immunomodulation process involvement in epilepsy, a phenomenon that was previously mainly seen in pediatric patients.

The effect of minocycline on seizures induced by amygdala kindling in rats

PURPOSE

Minocycline is known as a chemical with neuroprotective, anti-inflammatory, and antimicrobial properties. In this study, the effects of minocycline on seizures induced by amygdala kindling in rats were studied.

METHODS

Kindled Wistar rats were injected intraperitoneally with saline and, on the following day, with minocycline (50, 25, and 12.5mg/kg for the three groups (1-3), respectively). The animals in groups 1-3 had similar protocols. Groups 4 and 5 were given for the rotarod test and received 25 or 50mg/kg minocycline, respectively, without any kindling stimulation. The animals in groups 6 and 7 (seven each) received 25mg/kg minocycline or saline, respectively. All the injections were carried out 1h before kindling stimulation. Seizure parameters, including after discharge duration (ADD), stage 4 latency (S4L), stage 5 duration (S5D), and seizure duration (SD), were recorded and compared with those of the saline groups.

RESULTS

Minocycline (50mg/kg) significantly reduced ADD, 1/S4L, S5D, and SD (P<0.001, P<0.05, P<0.001, and P<0.001, respectively) in group 1. While the administration of 25mg/kg of minocycline decreased the ADD and S5D (P<0.05), in group 2. The injection of 12.5mg/kg resulted in decreased S5D (P<0.001) in group 3. The daily injection of minocycline (25mg/kg) significantly decreased ADD, S5D, and SD (P<0.001) in group 6.

CONCLUSION

The obtained results revealed that minocycline has anticonvulsant effect on seizures induced by amygdala kindling. Thus, it may be useful for epilepsy treatment.

Antiallergic effect of Trigonella foenum-graecum L. extracts on allergic skin inflammation induced by trimellitic anhydride in BALB/c mice

ETHNOPHARMACOLOGICAL RELEVANCE

Fenugreek (Trigonella foenum-graecum L.) has a wide variety of therapeutic properties for allergic and inflammatory diseases and is used as a traditional functional food, but its antiallergenic mechanism in these diseases is yet to be clearly elucidated.

AIM

In the present study, we investigated the antiallergic activity of fenugreek extract using trimellitic anhydride (TMA)-induced contact hypersensitivity (CHS) mice in vivo and ovalbumin (OVA)-immunized BALB/c mice ex vivo as represented model of T-helper (Th) 2-induced allergy.

MATERIALS AND METHODS

BALB/c mice were administered 250 mg/kg body weight (BW) of fenugreek extract for 7 days after sensitization and challenge treatment with 2-5% TMA. Ear thickness were noted, and the infiltration of eosinophils and mast cells was investigated by hematoxylin and eosin (H&E) and toluidine blue (TB) staining. The supernatants from homogenized ear and splenocytes were used for cytokine determination using ELISA. In addition, splenocytes from OVA-immunized BALB/c mice were treated with fenugreek extract ex vivo. The levels of cytokines present in the supernatants were determined by ELISA. The mRNA expression of T-box transcription factor 21 gene (T-bet), GATA-binding protein 3 (GATA-3), interferon (IFN)-γ, and interleukin (IL)-4 were evaluated by real-time RT-PCR.

RESULTS

Fenugreek extract was found to reduce ear thickness as well as the infiltration of eosinophils and mast cells. In homogenized ear, the production of IL-4, IL-5, IL-13, and IL-1β was suppressed. To determine the mechanism by which fenugreek extract inhibits allergic skin inflammation, detailed studies were conducted revealing that fenugreek extract prevented differentiation into Th2 cells in the splenocytes of OVA-induced allergic mice, resulting from suppressing the secretion of IL-4 and mRNA expression of GATA-3, an IL-4 transcription factor. In earlier phase, these extracts enhanced the secretion of IFN-γ, the mRNA expression of T-bet, an IFN-γ transcription factor, and the number of IFN-γ-producing CD4(+) T cells.

CONCLUSIONS

These results indicate that fenugreek extract cures Th2-induced allergic skin inflammation by enhancing Th1 differentiation. These data suggest that fenugreek extracts may prove to be an useful therapeutic agent on allergic inflammatory diseases as traditional use as well as Th2-mediated allergic response.

Immunoglobulin treatment for severe childhood epilepsy

We have used intravenous immunoglobulin to treat pediatric patients with various severe epileptic conditions. This retrospective, multicenter study comprised 64 consecutive patients treated with immunoglobulins for either epileptic encephalopathy or refractory epilepsy. The rate of full or partial improvement according to specific syndrome involved three of four patients with idiopathic West syndrome, six of 12 patients with electrical status epilepticus in sleep, eight of 19 patients with an undefined syndrome, one of three patients with Landau-Kleffner syndrome, and one of two patients with Rasmussen encephalitis. Intravenous immunoglobulins were ineffective in 10 patients with symptomatic West syndrome, nine with febrile infection-related status epilepticus, three with myoclonic astatic epilepsy, and two with Lennox-Gastaut syndrome. Nine patients (14%) demonstrated complete resolution, and 10 (15.6%) exhibited partial improvement. Of these 19 responders (29.7%), eight relapsed. Although intravenous immunoglobulin is not suitable for all cases of epilepsy, it may prove efficacious for specific epileptic syndromes, mainly idiopathic West syndrome and electrical status epilepticus during sleep.

Changing perspectives on Landau-Kleffner syndrome

Landau-Kleffner syndrome (LKS) is a childhood disorder characterized by an acquired aphasia that emerges in association with epileptiform electroencephalographic abnormalities. The language loss is often characterized by a severe disturbance of auditory language comprehension (verbal auditory agnosia) combined with a substantial disruption of expressive language. Comorbid behavioral disturbances commonly involve hyperactivity and attentional problems but sometimes encompass a more pervasive pattern of difficulties resembling an autism spectrum disorder. Now one the most frequently described forms of acquired aphasia in children, LKS has had a profound influence on both neurological practice and cognitive neuroscience. Here, we review current conceptualizations of LKS, consider its pleomorphic manifestations and discuss existing and future diagnostic issues and dilemmas. The potential relevance of LKS to understanding other disorders, including autistic regression, is considered.

The evaluation of treatment-resistant epilepsy

An estimated 10% to 40% of children with epilepsy have treatment-resistant epilepsy. Persistent seizures have negative psychosocial, behavioral, cognitive, and financial consequences and are associated with an increased mortality rate. Accurate syndromic and etiologic diagnoses are of vital importance because they may guide medical and/or surgical decision making. Revisitation of the history to confirm the diagnosis of epilepsy and the appropriateness of medication trials to date is vital. Routine imaging should include structural magnetic resonance imaging (MRI) with an established epilepsy protocol. In the setting of a normal previous MRI, repeat imaging may be indicated and may be supplemented with other imaging modalities. The admission for prolonged inpatient video-encephalographic monitoring may lead to a revision of a pre-existing diagnosis. Laboratory evaluations should include genetic, metabolic, and infectious/inflammatory studies when indicated. In this review, we discuss the implication of seizure semiology and syndrome classification when searching for an underlying diagnosis in treatment-resistant epilepsy, and will review both basic and more advanced procedures/studies that may aid diagnosis.

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.

Intravenous immunoglobulins for epilepsy

BACKGROUND

Epilepsy is a common neurological condition, with an estimated incidence of 50 per 100,000 persons. People with epilepsy may present with various types of immunological abnormalities, such as low serum IgA level, lack of IgG subclass and identification of certain types of antibodies. Intravenous immunoglobulin (IVIg) treatment may represent a valuable approach and its efficacy has important implications for epilepsy management.

OBJECTIVES

To examine the effects of IVIg on the frequency and duration of seizures, quality of life and adverse effects, when used as monotherapy or as add-on treatment for people with epilepsy.

SEARCH STRATEGY

We searched the Cochrane Epilepsy Group Specialized Register (14 June 2010), the Cochrane Central Register of Controlled Trials (Issue 2 of 4, The Cochrane Library, 2010), MEDLINE (1950 to June 2010), Web of Science (14 June 2010), Current Controlled Trials (11 June 2010), the National Research Register (NRR) archive (11 June 2010), the US National Institutes of Health (Clinicaltrials.gov) (11 June 2010) and reference lists of articles.

SELECTION CRITERIA

Randomized or quasi-randomized controlled trials of IVIg as monotherapy or add-on treatment in people with epilepsy.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed the trials for inclusion and extracted data. We contacted study authors for additional information. Outcomes included percentage of people rendered seizure-free, 50% or greater reduction in seizure frequency, adverse effects, treatment withdrawal and quality of life.

MAIN RESULTS

We included one study (61 patients). We found no randomized controlled trials that investigated the effects of IVIg monotherapy for epilepsy. The included study was a randomized, double-blind, placebo-controlled, multi-center trial which compared the treatment efficacy of IVIg as an add-on with a placebo add-on in patients with refractory epilepsy. There was no significant difference between IVIg and placebo in 50% or greater reduction in seizure frequency. The study reported a statistically significant effect for global assessment in favor of IVIg. No adverse effects were demonstrated.

AUTHORS' CONCLUSIONS

No reliable conclusions can be drawn regarding the efficacy of IVIg as a treatment for epilepsy. Further randomized controlled trials are needed.

Can Immune Disorders Influence Therapeutical Approach in Treatment of Epilepsy among Neurologists? A First Co-Operative National Recognition in Italy

Functional disturbances of the immune system have been detected more often among persons affected by epilepsy than in the general population. In the February-July period of 2007 a specific questionnaire on the relationship between epilepsy and immunological response was sent to 27 specialized Centres for Epilepsy in nine Italian regions. 15,388 epileptic patients attended twenty-seven Centers during this six-month period. 3.3% (n=502) of these patients suffered an immune disease. This is the first national survey on the relationship between epilepsy and immunological response in current clinical practice.

Microglial ablation and lipopolysaccharide preconditioning affects pilocarpine-induced seizures in mice

Activated microglia have been associated with neurodegeneration in patients and in animal models of Temporal Lobe Epilepsy (TLE), however their precise functions as neurotoxic or neuroprotective is a topic of significant investigation. To explore this, we examined the effects of pilocarpine-induced seizures in transgenic mice where microglia/macrophages were conditionally ablated. We found that unilateral ablation of microglia from the dorsal hippocampus did not alter acute seizure sensitivity. However, when this procedure was coupled with lipopolysaccharide (LPS) preconditioning (1 mg/kg given 24 h prior to acute seizure), we observed a significant pro-convulsant phenomenon. This effect was associated with lower metabolic activation in the ipsilateral hippocampus during acute seizures, and could be attributed to activity in the mossy fiber pathway. These findings reveal that preconditioning with LPS 24 h prior to seizure induction may have a protective effect which is abolished by unilateral hippocampal microglia/macrophage ablation.

Treatment of Lennox-Gastaut syndrome: overview and recent findings

Lennox-Gastaut syndrome (LGS) is a rare, age-related syndrome, characterized by multiple seizure types, a specific electro-encephalographic pattern, and mental regression. However, published data on the etiology, evolution, and therapeutic approach of LGS are contradictory, partly because the precise definition of LGS used in the literature varies. In the most recent classification, LGS belongs to the epileptic encephalopathies and is highly refractory to all antiepileptic drugs. Numerous treatments, medical and non-medical, have been proposed and results mostly from open studies or case series have been published. Sometimes, patients with LGS are included in a more global group of patients with refractory epilepsy. Only 6 randomized double-blind controlled trials of medical treatments, which included patients with LGS, have been published. Overall, treatment is rarely effective and the final prognosis remains poor in spite of new therapeutic strategies. Co-morbidities need specific treatment. This paper summarizes the definition, diagnosis and therapeutic approach to LGS, including not only recognized antiepileptic drugs, but also "off label" medications, immune therapy, diet, surgery and some perspectives for the future.

Seizure precipitants in children with intractable epilepsy

PURPOSE

To investigate the seizure precipitants in children with intractable epilepsy, and to determine any distinctive clinical features contributing to seizures in these patients.

METHODS

A questionnaire and seizure diary prepared by the parents of the patients. Demographic and seizure data were reviewed.

RESULTS

Of 120 patients with intractable epilepsy, 74 (62%) had one (n=43), two (n=23), or three seizure precipitants (n=8). The three most common precipitants were illness or fever (32%), sleep deprivation (13%), and menstruation (10%). Of these precipitants, inducing factors (endogenous origin) were more common than triggering factors (exogenous origin): 73% versus 27%, respectively. Three distinctive clinical features - neurological abnormalities (P=0.01), status epilepticus (P=0.017), and abnormal neuroimaging (P=0.007) - were significantly more common in patients with than in patients without precipitants.

CONCLUSIONS

Prompt recognition and management of seizure precipitants has practical implications for treating patients with refractory epilepsy. Such patients can be counseled to avoid specific precipitants.

Possible role of the innate immunity in temporal lobe epilepsy

PURPOSE

Temporal lobe epilepsy (TLE) is a multifactorial disease often involving the hippocampus. So far the etiology of the disease has remained elusive. In some pharmacoresistant TLE patients the hippocampus is surgically resected as treatment. To investigate the involvement of the immune system in human TLE, we performed large-scale gene expression profiling on this human hippocampal tissue.

METHODS

Microarray analysis was performed on hippocampal specimen from TLE patients with and without hippocampal sclerosis and from autopsy controls (n = 4 per group). We used a common reference pool design to perform an unbiased three-way comparison between the two patient groups and the autopsy controls. Differentially expressed genes were statistically analyzed for significant overrepresentation of gene ontology (GO) classes.

RESULTS

Three-way analysis identified 618 differentially expressed genes. GO analysis identified immunity and defense genes as most affected in TLE. Particularly, the chemokines CCL3 and CCL4 were highly (>10-fold) upregulated. Other highly affected gene classes include neuropeptides, chaperonins (protein protection), and the ubiquitin/proteasome system (protein degradation).

DISCUSSION

The strong upregulation of CCL3 and CCL4 implicates these chemokines in the etiology and pathogenesis of TLE. These chemokines, which are mainly expressed by glia, may directly or indirectly affect neuronal excitability. Genes and gene clusters identified here may provide targets for developing new TLE therapies and candidates for genetic research.

Intravenous Immunoglobulins in Refractory Childhood-Onset Epilepsy: Effects on Seizure Frequency, EEG Activity, and Cerebrospinal Fluid Cytokine Profile

PURPOSE

Several studies have reported favorable effects of intravenous immunoglobulins (IVIG) in refractory epilepsy. Evidence substantiating an immunomodulatory action is scarce. In an open-label study, we prospectively investigated the effect of IVIG on clinical, EEG and serum/CSF immunological parameters in patients with refractory childhood-onset epilepsy.

METHODS

Thirteen patients (median age 6.9 years; range 1.6-25.8) with refractory seizures despite 3-4 antiepileptic drug regimens were given IVIG (Sandoglobulin, ZLB-Behring, add-on, 4 x 400 mg/kg/3 weeks). Seizure frequency, 24-h video-EEG, and CSF/serum immunological parameters and cytokine profiles (IL-6/IL-8/IL-12/IL-10) were documented before and after completion of the course.

RESULTS

Seizure frequency was reduced by > or = 50% in four, and by 25%-50% in three patients. In contrast, variation in automatically recorded spike counts (1-h-wake and -sleep) did not correlate with clinical improvement. Serum immunological parameters showed variable deviations in eight patients (e.g., IgG(2) deficiency) and CSF immunoblotting showed oligoclonal bands in two patients. Blood-brain barrier permeability was normal in 12 patients. IL-6 and IL-8 were clearly detectable in CSF of all patients; the levels were significantly higher than those in plasma but remained unaffected by IVIG treatment.

CONCLUSIONS

Despite unchanged EEG spike counts, substantial reductions in seizure frequency occurred in 7 of 13 patients, suggesting that IVIG hinder progression of central epileptic activity into clinical seizures. Intrathecal presence of IL-8 and IL-6 was documented in all patients, but was unaffected by IVIG, suggesting that their production is directly related to electrical seizure activity and that IVIG may act through interference with immune pathways downstream to IL-6 and IL-8.

Lack of association between IL-1β/α gene polymorphisms and temporal lobe epilepsy with hippocampal sclerosis

Mesial temporal lobe epilepsy with hippocampal sclerosis (MTLE-HS) is one of the most common medically intractable epilepsy syndromes and the pathogenesis of HS remains highly obscure. Recent studies demonstrated controversial results about the relationship between interleukin (IL) gene polymorphism and epilepsy in different ethnic groups. This correlation was investigated in Turkish patients with MTLE-HS. The allele distribution of IL-1alpha and IL-1beta in 47 patients of Turkish ancestry was determined and compared with 99 ethnically matched control subjects. Analysis of genotype frequencies between patients and controls showed no statistically significant difference (p>0.05). Our data suggest that IL-1alpha and IL-1beta gene polymorphisms do not act as a strong susceptibility factor for MTLE-HS in individuals of Turkish ancestry.

Large-scale expression study of human mesial temporal lobe epilepsy: evidence for dysregulation of the neurotransmission and complement systems in the entorhinal cortex

Human mesial temporal lobe epilepsies (MTLE) are the most frequent form of partial epilepsies and display frequent pharmacoresistance. The molecular alterations underlying human MTLE remain poorly understood. A two-step transcriptional analysis consisting in cDNA microarray experiments followed by quantitative RT-PCR validations was performed. Because the entorhinal cortex (EC) plays an important role in the pathophysiology of the MTLE and usually discloses no detectable or little cell loss, resected EC and each corresponding lateral temporal neocortex (LTC) of MTLE patients were used as the source of disease-associated and control RNAs, respectively. Six genes encoding (i) a serotonin receptor (HTR2A) and a neuropeptide Y receptor type 1 (NPY1R), (ii) a protein (FHL2) associating with the KCNE1 (minK) potassium channel subunit and with presenilin-2 and (iii) three immune system-related proteins (C3, HLA-DR-gamma and CD99), were found consistently downregulated or upregulated in the EC of MTLE patients as compared with non-epileptic autopsy controls. Quantitative western blot analyses confirmed decreased expression of NPY1R in all eight MTLE patients tested. Immunohistochemistry experiments revealed the existence of a perivascular infiltration of C3 positive leucocytes and/or detected membrane attack complexes on a subset of neurons, within the EC of nine out of eleven MTLE patients. To summarize, a large-scale microarray expression study on the EC of MTLE patients led to the identification of six candidate genes for human MTLE pathophysiology. Altered expression of NPY1R and C3 was also demonstrated at the protein level. Overall, our data indicate that local dysregulation of the neurotransmission and complement systems in the EC is a frequent event in human MTLE.

Facilitation of spike-wave discharge activity by lipopolysaccharides in Wistar Albino Glaxo/Rijswijk rats

In normal rats the proinflammatory cytokines like interleukin-1beta, interleukin-6, which are induced by bacterial lipopolysaccharides, are able to control thalamo-cortical excitability by exerting strong effects on physiological synchronization such as sleep and on pathological synchronization like that in epileptic discharges. To investigate whether proinflammatory cytokines or lipopolysaccharides could modulate absence seizures resulting from a very different generator mechanism than the already investigated bicuculline-, kindling- and kainate-induced seizures, we used a genetically epileptic Wistar Albino Glaxo/Rijswijk rat strain, which is spontaneously generating high voltage spike-wave discharges. Wistar Albino Glaxo/Rijswijk rats responded with an increase of the number of spike-wave discharges to lipopolysaccharide injection (from 10 microg/kg to 350 microg/kg). Repetitive administration of 350 microg/kg lipopolysaccharides daily for 5 days increased the number of spike-wave discharges on the first, second and third days but the number of spike-wave discharges returned to the control value on day 5, at the 5th injection of lipopolysaccharides, showing a tolerance to lipopolysaccharides. The lipopolysaccharide-induced increase in spike-wave discharges was not directly correlated with the elevation of the core body temperature, as it is in febrile seizures, although lipopolysaccharide induced prostaglandin and is clearly pyrogenic at the doses used. Indomethacin, the prostaglandin synthesis inhibitor, efficiently blocked lipopolysaccharide-induced enhancement of spike-wave discharge genesis suggesting that the spike-wave discharge facilitating effect of lipopolysaccharides involves induction of cyclooxygenase 2 and subsequent synthesis and actions of prostaglandin E2. Low dose (40 mg/kg, i.p.) of competitive N-methyl-d-aspartate receptor antagonist 2-amino-5-phosphonopentanoic acid, and low dose of lipopolysaccharide (20 microg/kg) showed a synergistic interaction to increase the number of spike-wave discharges, whereas at supramaximal doses of lipopolysaccharide and the N-methyl-D-aspartate antagonist no synergy was present. The data reveal a functional connection between absence epileptic activity and lipopolysaccharide induction of prostaglandin synthesis and prostaglandin action and suggest some common cellular targets in epilepsy and lipopolysaccharide-induced inflammation.