A dysbalanced immune system in cryptogenic Lennox-Gastaut syndrome

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.

Reduced immunoglobulin levels in epilepsy patients treated with levetiracetam, lamotrigine, or carbamazepine

OBJECTIVES

The aim of the study was to investigate immunoglobulin levels in patients with epilepsy using the antiepileptic drugs (AED) levetiracetam (LEV), carbamazepine (CBZ), or lamotrigine (LTG).

METHODS

A total of 211 patients and 80 controls (age: 18-45 years) of both genders were included. The patients had been treated with either LEV (n = 47), CBZ (n = 90), or LTG (n = 74) monotherapy for at least 6 months. Total concentrations of immunoglobulin G (IgG), IgG subclasses (IgG1, IgG2, IgG3, and IgG4), immunoglobulin A (IgA), and immunoglobulin M (IgM) were measured. Smoking, drinking habits, and physical activity were recorded, and body mass index (BMI) was calculated.

RESULTS

A significantly lower total IgG and IgG1 was found in both men and women treated with LTG and in men on CBZ. IgG2 and IgG4 were also lower in LTG-treated women, and IgA and IgM were lower in LTG-treated men. Patients treated with LEV did not differ from the control group.

CONCLUSIONS

Low levels of immunoglobulins were found in patients with epilepsy treated with LTG or CBZ. As our group of patients consisted of otherwise healthy young adults, one should be especially aware of a possible effect of AEDs on immunoglobulin levels when treating selected patient groups, for example immunocompromised patients. Immunoglobulin concentrations should be measured in patients treated with LTG or CBZ who experience recurrent infections, and a change in medication should be considered.

High concentration of immunoglobulin A is associated with temporal lobe epilepsy

INTRODUCTION

Dysfunction of immunoglobulins (Igs) has been detected in association with antiepileptic drugs (AEDs) and in newly diagnosed epilepsy patients. The aim of this study was to evaluate the effect of clinical features and the current or past use of AEDs on serum Ig concentrations in a well-examined group of patients with refractory epilepsy.

PATIENTS AND METHODS

Using a nephelometric method, concentrations of IgA, IgG and IgM were analyzed in the sera of 257 patients with refractory epilepsy, 15 patients with controlled epilepsy and 584 healthy control subjects.

RESULTS

A low IgA concentration was found in 8.8% of the patients with epilepsy compared with 1.9% of the control subjects. High concentrations of IgA were associated with temporal lobe epilepsy (TLE) compared with other epilepsy types (p=0.042). The high concentrations of IgA (p=0.042), low concentrations of IgG (p=0.002), and high concentrations of IgG (p=0.008) were also associated with autoimmune diseases. The use of lamotrigine, nitrazepam, oxcarbazepine, topiramate and valproic acid was associated with alterations in Ig concentrations. Current use of topiramate was associated with high serum IgG and IgM concentrations (OR 10.39; 95% CI: 3.08-35.04 and OR 7.02; 95% CI: 1.25-39.55, respectively).

DISCUSSION

The finding of high serum IgA concentration in patients with TLE strengthens the previously found association of immunological activity in the epileptic temporal lobe rather than other brain regions. The newly observed immunological effects of topiramate are important to proper AED choice in patients with refractory epilepsy.

Antibodies to voltage-gated potassium and calcium channels in epilepsy

OBJECTIVE

To determine the prevalence of antibodies to ion channels in patients with long standing epilepsy.

BACKGROUND

Although the CNS is thought to be protected from circulating antibodies by the blood brain barrier, glutamate receptor antibodies have been reported in Rasmussen's encephalitis, glutamic acid decarboxylase (GAD) antibodies have been found in a few patients with epilepsy, and antibodies to voltage-gated potassium channels (VGKC) have been found in a non-paraneoplastic form of limbic encephalitis (with amnesia and seizures) that responds to immunosuppressive therapy.

METHODS

We retrospectively screened sera from female epilepsy patients (n=106) for autoantibodies to VGKC (Kv 1.1, 1.2 or 1.6), voltage-gated calcium channels (VGCC) (P/Q-type), and GAD. All positive results, based on the values of control data [McKnight, K., Jiang, Y., et al. (2005). Serum antibodies in epilepsy and seizure-associated disorders. Neurology 65, 1730-1735], were retested at lower serum concentrations, and results compared with previously published control data. Demographics, medical history, and epilepsy related information was gathered.

RESULTS

The studied group consisted predominantly of patients with long standing drug resistant epilepsy. VGKC antibodies were raised (>100 pM) in six patients. VGCC antibodies (>45 pM) were slightly raised in only one patient. GAD antibodies were <3 U/ml in all patients. The clinical features of the patients with VGKC antibodies differed from previously described patients with limbic encephalitis-like syndrome, and were not different with respect to seizure type, age at first seizure, duration of epilepsy, or use of anti-epileptic drugs from the VGKC antibody negative patients.

CONCLUSION

The results demonstrate that antibodies to VGKC are present in 6% of patients with typical long-standing epilepsy, but whether these antibodies are pathogenic or secondary to the primary disease process needs to be determined.

Epilepsy and the immune system: is there a link?

The concept that the immune system plays a role in the epileptogenic process of some epileptic syndromes was first proposed more than 20 years ago. Since then, numerous studies have reported on the existence of a variety of immunological alterations in epileptic patients, on the observation of favourable responses of refractory epilepsy syndromes to immunomodulatory treatment, and on the association of certain well-known immune-mediated disease states with epilepsy. This review comprehensively recapitulates the currently available evidence supporting or arguing against the possible involvement of the immune system in the pathogenesis of certain types of epilepsy. It is concluded that an abundance of facts is in support of this concept and that further studies should be directed at substantiating the pathogenic significance of (auto)immune responses in certain types of epilepsy. Current progress in the functional and molecular immunological research techniques will indisputably contribute to the elucidation of this link.

Immunologic aspects of West syndrome and evidence of plasma inhibitory effects on T cell function

STUDY OBJECTIVE: The purpose of this study was to assess the extent of immune dysfunction in a well-defined group of epileptic patients: children with diagnosis of West syndrome (WS) or with transitions to another age-related EEG patterns, the multifocal independent spikes (MIS), and the slow spike-wave complexes (Lennox-Gastaut syndrome - LGS). Thus, WS was studied at different points of the natural evolutive history of the disease. METHOD: A group of 50 patients (33 with WS, 10 with LGS and 7 with MIS) and 20 age-matched healthy controls were submitted to enumeration of T lymphocyte subsets: CD1, CD3, CD4, CD8, CD4/CD8 ratio and lymphocyte proliferation assay to phytohaemagglutinin (PHA), in the presence of autologous and AB, homologous plasma. Dinitrochlorobenzene (DNCB) skin test sensitization was performed only in patients. Determinations of IgG, IgA, and IgM serum levels were compared to standard values for Brazilian population in different age ranges. RESULTS: Sensitization to DNCB showed absent or low skin reactions in 76% of the patients. High levels of IgG (45.7%) and IgM (61.4%), and lower levels of IgA (23.9%) were detected in the serum of the patients. Enumeration of lymphocyte subsets in peripheral blood showed: low CD3+ (p<0.05), low CD4+ (p<0.05), high CD8+ (p<0.01) and low CD4+ / CD8+ ratio (p<0.001). The proportion of CD1+ cells in the control group was less than 3%, while ranged between 6 and 11 % in 18% of the patients. The in vitro PHA-induced T cell proliferation showed significantly low blastogenic indices only when patients, cells were cultured in presence of their own plasma. No differences in blastogenic indices were observed when the cells of patients and controls were cultured with human AB plasma. CONCLUSION: The immunodeficiency in WS was mainly characterized by anergy, impaired cell-mediated immunity, altered levels of immunoglobulins, presence of immature thymocytes in peripheral blood and functional impairment of T lymphocytes induced by plasma inhibitory factors.

Virological and immunological aspects of seizure disorders

The brain is a symptom-producing organ, and one of the symptoms due to a basic brain dysfunction is epilepsy. The pathophysiologic background is in most epilepsies multifactorial, as different pre-, peri-, and postnatal triggers or environmental conditions influence one or several genetic factors, where also gender is of importance. One of the genetic factors is immunodysfunction, and the trigger mechanism may be a virus infection. Viruses are the most common agents to which the human being is exposed throughout life. The herpes virus group is of special interest with respect to complications of the central nervous system. Herpes viruses, especially herpes simplex virus type 1 (HSV-1), human herpes virus type 6 (HHV-6), cytomegalovirus (CMV) and Epstein-Barr virus (EBV), are capable of establishing latent infection and reactivating under a variety of stimuli. In this review especially HHV-6 will be emphasized, as well as CMV in relation to Rasmussen's syndrome. The immunological aspects will focus on immunoglobulins, antibodies, especially the glutamate receptors, human leukocyte antigens, T- and B-lymphocytes, and their respective interaction with the antigen presenting cell. This course of events concerns the 'immunological synapse'. Finally, reports on herpes virus genomes in the human brain are discussed. A study on herpes viral DNA in brain tissue from patients operated for focal epilepsy is briefly mentioned.

Intravenous immunoglobulin in neurological disease: a specialist review

Treatment of neurological disorders with intravenous immunoglobulin (IVIg) is an increasing feature of our practice for an expanding range of indications. For some there is evidence of benefit from randomised controlled trials, whereas for others evidence is anecdotal. The relative rarity of some of the disorders means that good randomised control trials will be difficult to deliver. Meanwhile, the treatment is costly and pressure to "do something" in often distressing disorders considerable. This review follows a 1 day meeting of the authors in November 2000 and examines current evidence for the use of IVIg in neurological conditions and comments on mechanisms of action, delivery, safety and tolerability, and health economic issues. Evidence of efficacy has been classified into levels for healthcare interventions (tables 1 and 2).

[Neurocysticercosis and Lennox-Gastaut syndrome: case report]

Report of a girl with the epileptic, hydrocephalic and encephalitic form of neurocysticercosis, diagnosed by cerebrospinal fluid and computed tomography exams, during her second year of life and an evolution with multiple types of seizures, prolonged periods of intracranial hypertension due to obstruction in the ventriculoperitoneal shunt, psychomotor regression and blindness until she was 10 years old, when the Lennox-Gastaut syndrome was diagnosed. Nowadays the patient is 16 years old and presents complex partial seizures with automatism not completely controlled with clobazan and oxcarbazepine, associated to left spastic hemiparesis, universal hyperreflexia, psychomotor agitation, self-mutilation, amaurosis and severe mental retardation. The association between neurocysticercosis and Lennox-Gastaut syndrome was first described in 1973 by Frochtengarten & Scarante in a Brazilian girl with a similar clinical picture.

Absence of glutamic acid decarboxylase antibodies in childhood epilepsies

Glutamic acid decarboxylase antibodies are present in some patients with therapy-resistant epilepsy. The authors measured glutamic acid decarboxylase antibodies in an unselected population of 114 children with different types of epilepsy. Three children with temporal lobe epilepsy and six children with various other types of epilepsy had intractable epilepsy. None of the children tested positive for glutamic acid decarboxylase antibodies. The study suggests that glutamic acid decarboxylase antibody testing cannot be recommended in unselected cases of childhood epilepsy.

Community-based study of Lennox-Gastaut syndrome

PURPOSE

Before 1986, the spectrum of childhood epilepsies, including Lennox-Gastaut syndrome (LGS) and Doose syndrome (DS), known collectively as "epilepsia myoclonica astatica," was believed to represent a single disease. More recently, some investigators have considered these syndromes to be parts of a continuum. To clarify these theories, neurobiologic factors of the syndromes were studied to determine which qualities were shared and which were unique.

METHODS

A retrospective (1975-1985), community-based (Helsinki metropolitan area and the province of Uusimaa) study was designed to seek children with features of LGS and DS. It was assumed that recall bias and the selection of documented history would be similar throughout the group. Ranks of increasing pathology were assigned to different seizure types, EEG results, and drug treatments. A similar procedure was applied to epidemiologic data. Spearman rank-order correlations were calculated to determine which features correlated with LGS and which correlated with less severe epilepsy.

RESULTS

The survey comprised 75 patients with broadly defined LGS. The annual incidence was 2 in 100,000 children aged 0 to 14 years. Prenatal or perinatal abnormalities did not correlate with severity of epilepsy. As compared with the relatively favorable ranks, the severe epilepsy ranks were more often associated with an early onset of epilepsy, an infectious disease at the onset, delayed development before epilepsy, abnormalities in neurologic or neuroradiologic examinations, and a deteriorating course of the condition.

CONCLUSIONS

Patients with LGS are more likely than patients with less severe epilepsy to have a younger age at onset of epilepsy, an infection or both, and a deteriorating course of the condition.

Lamotrigine adjunctive therapy in childhood epileptic encephalopathy (the Lennox Gastaut syndrome)

PURPOSE

We assessed efficacy and safety of adjunctive lamotrigine (LTG) therapy in patients with the Lennox-Gastaut syndrome (LGS).

METHODS

The study was a single-center, retrospective chart review of open-label adjunctive LTG therapy in patients with LGS. Initial LTG dose and titration was dependent on concomitant antiepileptic drugs (AEDs). Efficacy was based on the change in seizure frequency between the initiation of LTG therapy and December 1, 1995 (or LTG discontinuation). Seizure diaries were used to count patient seizures. A secondary evaluation of efficacy was a parental or guardian assessment of the patient's global status. The evaluation of safety involved chart review for treatment-emergent adverse events (AE).

RESULTS

Data from 16 LGS patients were analyzed. Fifty-three percent (8 of 15) had a > 50% reduction in seizure frequency with LTG adjunctive therapy. Tonic, atonic, generalized tonic-clonic (GTCS), and atypical absence seizure frequency but not myoclonic seizure frequency decreased significantly during LTG therapy. Fifty-three percent of the patient's parents (8 of 15) reported that their child's quality of life (QOL) was much or very much improved during the study. The major treatment-emergent AE were infection (50%, 8 of 16) and sleep disturbance (19%, 3 of 16). A rash was noted in 13% (2 of 16) of the patients and resulted in LTG discontinuation in 1. No clinically significant changes were noted in neurologic examination or laboratory tests during the study.

CONCLUSIONS

Our results indicate that LTG adjunctive therapy is effective and well tolerated in patients with LGS.