Anticardiolipin and antinuclear antibodies in epilepsy—a population-based cross-sectional study

Elevated IL-6 plasma levels are associated with GAD antibodies-associated autoimmune epilepsy

Background

Antibodies against glutamic acid decarboxylase (GADA) are present in multiple neurological manifestations, such as stiff-person syndrome, cerebellar ataxia, limbic encephalitis, and epilepsy. Increasing data support the clinical significance of GADA as an autoimmune etiology of epilepsy, however, there is not yet definitive evidence to confirm the pathogenic link between GADA and epilepsy.

Objective

Interleukin-6 (IL-6), a pro-convulsive and neurotoxic cytokine, and interleukin-10 (IL-10), an anti-inflammatory and neuroprotective cytokine, are crucial inflammatory mediators in the brain. Increased production of IL-6 and its association with epileptic disease profiles are well established, suggesting the presence of chronic systemic inflammation in epilepsy. Therefore, in this study, we investigated the association of plasma cytokine concentrations of IL-6 and IL-10 and their ratio with GADA in patients with drug-resistant epilepsy.

Methods

Interleukin-6 and IL-10 concentrations were measured by ELISA in plasma, and the IL-6/IL-10 ratio was calculated in a cross-sectional cohort of 247 patients with epilepsy who had their GADA titers measured previously for their clinical significance in epilepsy. Based on GADA titers, patients were grouped as GADA negative (n = 238), GADA low positive (antibody titers < 1,000 RU/mL, n = 5), and GADA high positive (antibody titers ≥ 1,000 RU/mL, n = 4).

Results

Median IL-6 concentrations were significantly higher in patients with high GADA positivity [2.86 pg/mL, interquartile range (IQR) = 1.90-5.34 pg/mL] than in GADA-negative patients [1.18 pg/mL, interquartile range (IQR) = 0.54-2.32 pg/mL; p = 0.039]. Similarly, IL-10 concentrations were also higher in GADA high-positive patients [1.45 pg/mL, interquartile range (IQR) = 0.53-14.32 pg/mL] than in GADA-negative patients [0.50 pg/mL, interquartile range (IQR) = 0.24-1.00 pg/mL], however, the difference was not statistically significant (p = 0.110). Neither IL-6 nor IL-10 concentrations were different between GADA-negative and GADA low-positive patients (p > 0.05) or between GADA low-positive or GADA high-positive patients (p > 0.05). The IL-6/IL-10 ratio was also similar among all the study groups.

Conclusion

Increased circulatory concentrations of IL-6 are associated with high GADA titers in patients with epilepsy. These data provide additional pathophysiological significance of IL-6 and help to further describe the immune mechanisms involved in the pathogenesis of GADA-associated autoimmune epilepsy.

Seizures in systemic lupus erythematosus: A scoping review

Systemic lupus erythematosus is a systemic autoimmune disease that affects the central nervous system, either by direct neuronal damage, injury to brain vessels, or by pathogenic mechanisms indirectly induced by immune mechanisms related to the production and deposition of immune complexes. The prevalence of explicit episodes of seizures among SLE patients, varies from 2 to 8%. In some cases, patients with positivity for antiphospholipid or anti-β2 glycoprotein antibodies are found to be more prone to exhibit seizures compared to seronegative patients, other subjects at risk are carries of gene abnormalities codifying for ion channels. The exclusion of vasculitis or thrombosis is required for accurate treatment, imaging studies and alternative sequences are mandatory in patients with known SLE who present with a seizure. Several statements regarding SLE-related seizure remain to be decoded. In this scoping review we analyzed published information about prevalence, pathogenesis, clinical characteristics, diagnostic and therapeutic SLE patients that manifest a seizure, our objective is to provide with useful information for prompt diagnosis and individualized treatment.

[Mental disorders and cognitive impairment in patients with antiphospholipid syndrome]

Mental disorders (mainly anxiety and depressive disorders) and cognitive impairment are often found in patients with antiphospholipid syndrome (APS), but their prevalence, structure, and mechanisms of occurrence are not well researched. The review provides literature data on the frequency, spectrum and possible causes of mental disorders and cognitive impairment in patients with APS, the pathogenetic mechanisms of these disorders (in particular, the important role of antiphospholipid antibodies, stress factors, chronic inflammation), the relationship between APS, mental disorders and as well as cognitive impairment is examined. Special attention is paid to the influence of mental disorders and cognitive impairment on patients adherence to treatment, their quality of life, as well as the particularities of psychopharmacotherapy of mental disorders in patients with APS. The aim of the review is to actualize the interdisciplinary problem of mental disorders and cognitive impairment in patients with APS and the need to introduce a partnership model of care.

Neurological autoantibodies in drug-resistant epilepsy of unknown cause

BACKGROUND

Autoimmune epilepsy is a rarely diagnosed condition. Recognition of the underlying autoimmune condition is important, as these patients can be resistant to antiepileptic drugs.

AIMS

To determine the autoimmune and oncological antibodies in adult drug-resistant epilepsy of unknown cause and identify the clinical, radiological, and EEG findings associated with these antibodies according to data in the literature.

METHODS

Eighty-two patients with drug-resistant epilepsy of unknown cause were prospectively identified. Clinical features were recorded. The levels of anti-voltage-gated potassium channel complex (anti-VGKCc), anti-thyroid peroxidase (anti-TPO), anti-nuclear antibody (ANA), anti-glutamic acid decarboxylase (anti-GAD), anti-phospholipid IgG and IgM, anti-cardiolipin IgG and IgM, and onconeural antibodies were determined.

RESULTS

Serum antibody positivity suggesting the potential role of autoimmunity in the aetiology was present in 17 patients with resistant epilepsy (22.0%). Multiple antibodies were found in two patients (2.6%). One of these patients (1.3%) had anti-VGKCc and ANA, whereas another (1.3%) had anti-VGKCc and anti-TPO. A single antibody was present in 15 patients (19.5%). Of the 77 patients finally included in the study, 4 had anti-TPO (5.2%), 1 had anti-GAD (1.3%), 4 had anti-VGKCc (5.2%) 8 had ANA (10.3%), and 2 had onconeural antibodies (2.6%) (1 patient had anti-Yo and 1 had anti-MA2/TA). The other antibodies investigated were not detected. EEG abnormality (focal), focal seizure incidence, and frequent seizures were more common in antibody-positive patients.

CONCLUSION

Autoimmune factors may be aetiologically relevant in patients with drug-resistant epilepsy of unknown cause, especially if focal seizures are present together with focal EEG abnormality and frequent seizures.

Hughes syndrome and epilepsy: when to test for antiphospholipid antibodies?

Epilepsy and seizures are reported among the neurological manifestations of antiphospholipid syndrome (APS) at a prevalence rate of approximately 8%, which is nearly 10 times the prevalence of epilepsy in the general population. The association of seizures with antiphospholipid antibodies (aPL) is even more significant in the presence of systemic lupus erythematosus (SLE). In this review, we discuss the epidemiological, pathophysiological, laboratory, clinical, and radiological aspects of this association, and derive suggestions on when to consider testing for aPL in epileptic patients and how to manage seizures secondary to APS based on literature data. Epilepsy due to APS should be considered in young patients presenting with seizures of unknown origin. Temporal lobe epilepsy seems to be particularly prevalent in APS patients. The pathogenesis is complex and may not only involve micro-thrombosis, but also a possible immune-mediated neuronal damage. Patients with seizures and positive aPL tend to develop thrombocytopenia and livedo racemosa more frequently compared with those without aPL. Magnetic resonance imaging (MRI) remains the imaging modality of choice in these patients. The presence of SLE and the presence of neurological symptoms significantly correlate with the presence of white matter changes on MRI. In contrast, the correlation between aPL positivity and the presence of white matter changes is very weak. Furthermore, MRI can be normal in more than 30–40% of neuropsychiatric lupus patients with or without aPL. aPL testing is recommended in young patients presenting with atypical seizures and multiple hyper-intensity lesions on brain MRI in the absence of other possible conditions. New MRI techniques can better understand the pathology of brain damage in neuro-APS. The therapeutic management of epileptic APS patients relies on anti-epileptic treatment and anticoagulant agents when there is evidence of a thrombotic event. In the absence of consensual recommendations, the decision of lifelong anticoagulation is discussed on a case-by-case basis. The anti-thrombotic benefit of hydroxychloroquine and statins is supported by several studies.

Epilepsy as part of systemic lupus erythematosus and systemic antiphospholipid syndrome (Hughes syndrome)

The antiphospholipid syndrome (APS) is defined by the presence of antiphospholipid antibodies (aPL), demonstrated by ELISAs for antibodies against phospholipids and associated phospholipid-binding cofactor proteins and/or a circulating lupus anticoagulant (LA) together with diverse systemic clinical manifestations such as thrombosis, and recurrent spontaneous abortions. According to the criteria set out in Sydney1 the only neurological manifestations that can be suitable as APS classification criteria are ischemic events (stroke and transient ischemic attacks). However, other neurological manifestations, including seizures in particular, have been repeatedly reported in APS patients.2

The present review will summarize recent research on the association of aPL, as well as other autoantibodies, with seizure disorders, with or without concomitant SLE.

Predictors of Incident Seizure in Systemic Lupus Erythematosus

OBJECTIVE

The risk factors for incident seizures in systemic lupus erythematosus (SLE) were prospectively determined in a cohort study.

METHODS

A total of 2203 patients with SLE followed longitudinally in the Hopkins Lupus Cohort were analyzed. Demographic variables, clinical manifestations, laboratory tests, and SLE disease activity were recorded at each quarterly visit. Adjusted estimates of association of risk factors for onset of seizure were derived using pooled logistic regression. We examined incident seizures in 3 ways: at the time of diagnosis, more than 45 days after the diagnosis of SLE, and after cohort entry.

RESULTS

Of 2203 patients with no history of seizure prior to SLE diagnosis, 157 (7.13%) had the first seizure occurrence at the time of (37 patients, 1.68%) or after diagnosis (120 patients, 5.45%) of SLE. The risk of seizure occurring around the time of SLE diagnosis was higher in patients with a history of malar rash (p = 0.002), proteinuria (p = 0.004), and psychosis (p < 0.001). Multivariable analysis of the first seizure occurring after the diagnosis of SLE showed that history of low C3 (p = 0.0078), psychosis (p < 0.0001), cranial or peripheral neuropathy (p = 0.0043), anti-Sm antibody (p = 0.0551), renal involvement (p = 0.0177), and current corticosteroid dose (p < 0.0001) were independently associated with a higher incidence of seizure. Disease activity was not predictive after adjusting for corticosteroids.

CONCLUSION

Risk of seizure after diagnosis of SLE is increased in those patients with prior psychosis, neuropathy, proteinuria, anti-Sm, low C3, and use of corticosteroids.

Antithyroid Antibodies Are Implicated in Epileptogenesis of Adult Patients With Epilepsy

Antithyroid antibodies (Abs) are associated with epilepsy in steroid-responsive encephalopathy, but have been rarely studied in unselected epilepsy patients. This study aimed to characterize the prevalence and associated factors of antithyroid Abs and other auto-Abs in adult patients with epilepsy.Epilepsy patients without autoimmune disorders were surveyed for antinuclear antibody (ANA), anti-β2 glycoprotein 1 antibody (aβ2GP1), anticardiolipin IgG Ab, antimicrosomal antibody (AMA), antithyroglobulin antibody (ATA), and thyroid function test.Of 319 patients, 75 (23.5%) were positive for at least 1 Ab. The most common Ab was anticardiolipin antibody (aCL) (30/319, 9.4%), followed by AMA (24/319, 7.5%), ANA (18/319, 5.6%), aβ2GP1 (18/319, 6.5%), and ATA (6/319, 3.25%). Antimicrosomal Abs were significantly more frequent in patients who were female, older at disease onset, older at the time of study, and had unknown seizure etiology. The presence of aCL was significantly associated with more frequent seizures. Most patients with antithyroid Ab were female and had focal seizures with unknown etiology.The association of different auto-Abs with different factors suggests that they may have different roles in adult patients with epilepsy. Recurrent seizures and certain antiepileptic medications may cause the production of aCL. The role of antithyroid Abs in adult focal epilepsy with unknown cause, especially in females, warrants further evaluation because of the potential implications on treatment.

Autoimmunity-related immunological serum markers and survival in a tertiary care cohort of adult patients with epilepsy

We evaluated mortality in relation to a panel of autoimmunity-related immunological serum markers in adult patients with epilepsy (PWE), seen in 1996-1997 at the Department of Neurology, Oulu University Hospital in Finland. Blood samples were drawn from 968 volunteers, and baseline measurements included serum immunoglobulins (IgG, IgA, and IgM), and the following antibodies: anticardiolipin, antinuclear, antimitochondrial, antigliadin (IgA and IgG classes), IgA tissue transglutaminase, and IgA endomysial. Hazard ratios (HR) for all-cause mortality in PWE with abnormal immunological markers relative to 413 patients with normal findings were evaluated with adjustment for confounders during a follow-up of nine years. Borderline statistically significant associations were found only for elevated IgA (HR 2.09, 95% CI 0.99-4.42) and for having two or more abnormal antibody titers (HR 1.58, 95% CI 0.98-2.56). The findings of this exploratory study suggested that elevated serum IgA might be associated with excess mortality in PWE.

Lack of antibodies to NMDAR or VGKC-complex in GAD and cardiolipin antibody-positive refractory epilepsy

BACKGROUND

Over the last few years autoantibodies against neuronal proteins have been identified in several forms of autoimmune encephalitis and epilepsy. NMDA receptor (NMDAR) and voltage gated potassium channel (VGKC) complex antibodies are mainly associated with limbic encephalitis (LE) whereas glutamic acid decarboxylase antibodies (GADA) and anticardiolipin (ACL) antibodies are more commonly detected in patients with chronic epilepsy. Clinical features vary between these antibodies suggesting the specificity of different neuronal antibodies in seizures.

METHODS

Serum samples of 14 GADA positive and 24 ACL positive patients with refractory epilepsy were analyzed for the presence of VGKC or NMDAR antibodies.

RESULTS

No positive VGKC or NMDAR antibodies were found in these patients.

CONCLUSIONS

The results confirm the different significance of these neuronal antibodies in seizure disorders. Different autoantibodies have different significance in seizures and probably have different pathophysiological mechanisms of actions.

Immunological perspectives of temporal lobe seizures

The temporal lobes are affected in many different neurological disorders, such as neurodegenerative diseases, viral and immunological encephalitides, and epilepsy. Both experimental and clinical evidence suggests a different inflammatory response to seizures in patients with temporal lobe epilepsy (TLE) in comparison to those with extra-TLE (XTLE). Proinflammatory cytokines and several autoantibodies have been shown to be associated with TLE compared to other epilepsy types suggesting the specific role and structure of the temporal lobe. Abundant experience suggests that activation of both innate and adaptive immunity is associated with epilepsy, particularly refractory focal epilepsy. Limbic encephalitis often triggers temporal lobe seizures, and a proportion of these disorders are immune-mediated. Histological evidence shows activation of specific inflammatory pathways in resected temporal lobes of epileptic patients, and certain epileptic disorders have shown increased incidence in patients with autoimmune diseases. Rapid activation of proinflammatory cytokines is observed after single seizures, but there is also evidence of chronic overproduction of cytokines and other inflammatory mediators in patients with TLE, suggesting a neuromodulatory role of inflammation in epilepsy. In this review we summarize current data on the presence and the role of immunological factors in temporal lobe seizures, and their possible involvement in epileptogenesis.

Intracellular and circulating neuronal antinuclear antibodies in human epilepsy

There are overwhelming data supporting the inflammatory origin of some epilepsies (e.g., Rasmussen's encephalitis and limbic encephalitis). Inflammatory epilepsies with an autoimmune component are characterized by autoantibodies against membrane-bound, intracellular or secreted proteins (e.g., voltage gated potassium channels). Comparably, little is known regarding autoantibodies targeting nuclear antigen. We tested the hypothesis that in addition to known epilepsy-related autoantigens, the human brain tissue and serum from patients with epilepsy contain autoantibodies recognizing nuclear targets. We also determined the specific nuclear proteins acting as autoantigen in patients with epilepsy. Brain tissue samples were obtained from patients undergoing brain resections to treat refractory seizures, from the brain with arteriovenous malformations or from post-mortem multiple sclerosis brain. Patients with epilepsy had no known history of autoimmune disease and were not diagnosed with autoimmune epilepsy. Tissue was processed for immunohistochemical staining. We also obtained subcellular fractions to extract intracellular IgGs. After separating nuclear antibody-antigen complexes, the purified autoantigen was analyzed by mass spectrometry. Western blots using autoantigen or total histones were probed to detect the presence of antinuclear antibodies in the serum of patients with epilepsy. Additionally, HEp-2 assays and antinuclear antibody ELISA were used to detect the staining pattern and specific presence of antinuclear antibodies in the serum of patients with epilepsy. Brain regions from patients with epilepsy characterized by blood-brain barrier disruption (visualized by extravasated albumin) contained extravasated IgGs. Intracellular antibodies were found in epilepsy (n=13/13) but not in multiple sclerosis brain (n=4/4). In the brain from patients with epilepsy, neurons displayed higher levels of nuclear IgGs compared to glia. IgG colocalized with extravasated albumin. All subcellular fractions from brain resections of patients with epilepsy contained extravasated IgGs (n=10/10), but epileptogenic cortex, where seizures originated from, displayed the highest levels of chromatin-bound IgGs. In the nuclear IgG pool, anti-histone autoantibodies were identified by two independent immunodetection methods. HEp-2 assay and ELISA confirmed the presence of anti-histone (n=5/8) and anti-chromatin antibodies in the serum from patients with epilepsy. We developed a multi-step approach to unmask autoantigens in the brain and sera of patients with epilepsy. This approach revealed antigen-bound antinuclear antibodies in neurons and free antinuclear IgGs in the serum of patients with epilepsy. Conditions with blood-brain barrier disruption but not seizures, were characterized by extravasated but not chromatin-bound IgGs. Our results show that the pool of intracellular IgG in the brain of patients with epilepsy consists of nucleus-specific autoantibodies targeting chromatin and histones. Seizures may be the trigger of neuronal uptake of antinuclear antibodies.

Epilepsy associated with systemic autoimmune disorders

Systemic autoimmune disorders affect multiple organ systems. Brain involvement commonly causes seizures, which may be the presenting symptom. Systemic lupus erythematosus, Sjorgren's syndrome, Wegener's granulomatosis, sarcoidsosis, celiac disease, Crohn's disease, Behcet's, and Hashimoto's encephalopathy are reviewed. Mechanisms underlying CNS pathology in systemic autoimmune disorders-and specifically factors predisposing these patients-are discussed, including vascular disease (e.g., prothrombotic state, anticardiolipin antibody, emboli, vasculitis), antineuronal antibodies, immune complexes, cytokines, metabolic disorders, infection, and therapy. Diagnostic and therapeutic strategies must be individualized for both the disorder and the patient. Systemic autoimmune disorders affect multiple organ systems and frequently involve the central and peripheral nervous systems. Seizures are among the most common neurological manifestation and occasionally can be the presenting symptom. There are many causes of seizures in systemic autoimmune disorders (Table 1), and the first clinical challenge is to determine not only the cause but also the significance of seizures. In some cases, they are clues to metabolic or infectious disorders or medication toxicity; in other cases, seizures herald a life-threatening progression of the underlying illness.

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.

Characterization of insulin secretion in Valproate-treated patients with epilepsy

PURPOSE

Valproate (VPA) treatment has been reported to be associated with obesity and high fasting serum insulin concentrations in parallel with an unfavorable serum lipid profile and hyperandrogenism and polycystic ovaries in women. The pathogenetic mechanism underlying these changes has remained unknown, although several mechanisms have been implicated.

METHODS

Fifty-one patients receiving monotherapy (31 male and 20 female patients) were included in this study, with 45 (23 male and 22 female) healthy control subjects. These participants were interviewed, clinically examined, and blood samples for fasting plasma glucose, serum insulin, proinsulin, and C-peptide concentrations were taken after an overnight fast.

RESULTS

The valproate-treated patients had fasting hyperinsulinemia (11.30 +/- 6.23 pM vs. 6.28 +/- 4.66 pM in the control subjects; p < 0.001), although the fasting serum proinsulin and C-peptide concentrations were not significantly higher in the patients than in the control subjects. In addition, proinsulin/insulin (0.30 +/- 0.14) and C-peptide/insulin ratios (35.48 +/- 24.09) were lower (p < 0.001) in the VPA-treated patients when compared with the control subjects (0.53 +/- 0.36 and 94.27 +/- 61.85, respectively), and they also had lower fasting plasma glucose concentrations (4.72 +/- 0.35 mM) than the control subjects (5.12 +/- 0.58 mM; p < 0.01).

CONCLUSIONS

This study suggests that valproate does not induce insulin secretion but might interfere with the insulin metabolism in the liver, resulting in higher insulin concentrations in the peripheral circulation. These changes are seen irrespective of concomitant weight gain, suggesting that increased insulin concentrations induce weight gain and not vice versa.

Cerebral Manifestations in the Antiphospholipid (Hughes) Syndrome

The importance of cerebral disease in patients with the Hughes syndrome is now becoming more widely recognized. The range of neuropsychiatric manifestations of APS is comprehensive, and includes focal symptoms attributable to lesions in a specific area of the brain as well as diffuse or global dysfunction. Patients with APS frequently present with strokes and TIA, but a wide spectrum of other neurologic features-also including non thrombotic neurologic syndromes-has been described in association with the presence of aPL. The recognition of APS has had a profound impact on the understanding and management of the treatment of CNS manifestations associated with connective tissue diseases, in particular, SLE. Many patients with focal neurologic manifestations and aPL, who a few years ago would have received high-dose corticosteroids or immunosuppression, are often successfully treated with anticoagulation. In our opinion, testing for aPL may have a major diagnostic and therapeutic impact not only in patients with autoimmune diseases and neuropsychiatric manifestations, but also in young individuals who develop cerebral ischemia, in those with atypical multiple sclerosis, transverse myelitis, and atypical seizures. We would also recommend testing for aPL for young individuals found with multiple hyperintensity lesions on brain MRI in the absence of other possible causes,especially when under the age of 40 years. It is our practice to anticoagulate patients with aPL suffering from cerebral ischemia with a target INR of 3.0 to prevent recurrences. Low-dose aspirin alone (with occasional exceptions)does not seem helpful to prevent recurrent thrombosis in these patients. Our recommendation, once the patient has had a proven thrombosis associated with aPL, is long-term (possibly life-long) warfarin therapy. Oral anti coagulation carries a risk of hemorrhage, but in our experience the risk of serious bleeding in patients with APS and previous thrombosis treated with oral anticoagulation to a target INR of 3.5 was similar to that in groups of patients treated with lower target ratios. Although a double-blind crossover trial comparing low molecular weight heparin with placebo in patients with aPL and chronic headaches did not show a significant difference in the beneficial effect of low molecular weight heparin versus placebo, in our experience selected patients with aPL and neuropsychiatric manifestations such as seizures, severe cognitive dys-function, and intractable headaches unresponsive to conventional treatment may respond to anticoagulant treatment. The neurologic ramifications of Hughes syndrome are extensive, and it behoves clinicians in all specialties to be aware of this syndrome because treatment with anticoagulation may profoundly change the outlook for these patients.

Hughes syndrome, the antiphospholipid syndrome: a new chapter in neurology

The importance of cerebral disease in patients with the antiphospholipid (Hughes) syndrome (APS) is now becoming more widely recognized. The range of neuropsychiatric manifestations of APS is comprehensive and includes focal symptoms attributable to lesions in a specific area of the brain as well as diffuse or global dysfunction. Patients with APS frequently present with strokes and transient ischemic attacks, but a wide spectrum of other neurologic features, also including nonthrombotic neurological syndromes, has been described in association with the presence of antiphospholipid antibodies. In this review, we attempt to highlight the large variety of the neurological features of APS.

Insulin-related metabolic changes during treatment with valproate in patients with epilepsy

Weight gain is a known side effect of valproate (VPA) therapy, which is associated with hyperinsulinemia and polycystic ovary-like syndrome and unfavorable lipid changes in women. Hyperinsulinemia has also been observed in male and lean subjects as well. Hyperinsulinemia is associated with several health risks, such as cardiovascular diseases and the metabolic syndrome. The purpose of this study was to evaluate whether VPA-related hyperinsulinemia is associated with other metabolic changes and whether there is any association between weight gain, other adverse effects related to VPA, and the metabolic syndrome. Fifty-one patients under VPA monotherapy and 45 healthy control subjects participated in the study. They were interviewed and clinically examined, and, after an overnight fast, blood samples were taken to evaluate fasting serum insulin, lipid, free fatty acid, and uric acid levels. Incidence of the metabolic syndrome was determined as well. Compared with control subjects, VPA-treated patients had higher circulating insulin concentrations relative to body mass index, higher uric acid and triglyceride levels, and lower high-density lipoprotein cholesterol concentrations. There was no significant difference in the frequency of the metabolic syndrome between the VPA-treated patient group and the control group. In conclusion, valproate therapy, especially if started at a young age, is associated with increased circulating insulin concentrations relative to body mass index, indicating that the high insulin levels are not a consequence of obesity. Although the frequency of the metabolic syndrome did not differ between VPA-treated patients and control subjects, VPA-treated patients had higher concentrations of triglycerides and uric acid and lower levels of high-density lipoprotein cholesterol than control subjects.

Antimitochondrial antibodies in patients with epilepsy

Immune mechanisms have been implicated in the pathogenesis of epilepsy. An increased prevalence of autoantibodies, as well as changes in serum immunoglobulin concentrations, has been reported in patients with epilepsy. The presence of unspecific antimitochondrial antibodies (AMAs) and their possible associations with other immunological markers were evaluated in a cohort of 1386 adult patients with epilepsy and population-based reference subjects. Unspecific AMAs were more frequent in epilepsy patients than in the reference group. Thirty-seven epilepsy patients (3.9%) and eleven control subjects (1.9%) had unspecific AMAs (RR 2.1, CI 1.05-4.1, P=0.03). These antibodies were associated with long duration of epilepsy and old age at the onset of epilepsy among patients with epilepsy. Their presence was independent of other immunological markers, comorbidity, and epilepsy medications.

Serum IgA, IgG, and IgM concentrations in patients with epilepsy and matched controls: a cohort-based cross-sectional study

Conflicting reports have been published on serum immunoglobulin (Ig) concentrations in patients with epilepsy. Serum IgA, IgG, and IgM concentrations were determined in a cohort of 958 patients and in a reference population of 581 subjects. Overall, 8.2% of patients with epilepsy and 1.9% of control subjects had low serum IgA concentrations. Low serum IgA levels were measured in 19.1% of patients currently on phenytoin therapy and in 11.9% of patients who had previously been treated with phenytoin, whereas only 3.8% of patients who had never been on phenytoin therapy had low serum IgA. In multivariate analysis low serum IgA concentrations were associated with phenytoin medication and female gender. No differences in serum IgG and IgM concentrations were observed between patients and control subjects. However, in patients with epilepsy, low serum IgG concentrations were associated with concomitant autoimmune diseases, and low IgM levels with older age at the onset of epilepsy, long duration of epilepsy, and autoimmune diseases. In conclusion, the prevalence of low serum IgA concentrations was increased in patients with epilepsy, but serum IgG and IgM concentrations were similar in patients with epilepsy and reference subjects. The low serum IgA concentrations were associated with phenytoin medication. In addition to current phenytoin medication, previous phenytoin therapy also was associated with low serum IgA concentrations. This implies that phenytoin medication may have permanent immunological effects in some patients.

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.