Immunoglobulin subgroups in children with febrile seizures

Nephelometry vs. Immunoturbidimetry assay: Analytical performance on IgG subclasses

Interest in measuring immunoglobulin G Subclasses (IgG Subclasses) is increasing as more information is gathered and understanding regarding conditions associated with deficiencies of each IgG Subclass grows. Different methodologies are available for the measurement of IgG Subclasses, but their specificities vary. As a result, laboratories choose the methodology that better suits their routine, but which may not necessarily align with the needs of their population. In addition, the lack of standardization for the quantification of IgG Subclasses causes diagnostic gaps when comparing results provided by different methodologies. Thus, the purpose of our research is to compare the analytical performance of The Binding Site's (TBS) Optilite® human Immunoglobulin G (IgG) and IgG Subclasses Immunoturbidimetry assay, with the Nephelometry method routinely used in our clinical laboratory, Siemens BNII®. Our results show that the Immunoturbidimetry assay appears to be the most reliable to evaluate IgG Subclasses: the sum of IgG Subclasses and Total IgG correlate better than by Nephelometry. Although these methodologies share a similar principle, the comparison of results appears to be compromised. Therefore, prior to switching methodologies, further studies should be conducted to assess which methodology could be better applied to specific populations. It is also essential to standardise IgG Subclasses assays to reduce discrepancies that arise from comparing results.

Determining the Role of Immunoglobulin Levels in Children with Febrile Seizures

Background

Febrile seizures are the most common form of convulsive disorder in childhood. The mechanisms underlying the pathogenesis of febrile seizure remain unclear.

Objective

The aim of this study was to assess the immunoglobulin (IG) sub-group levels in children with febrile seizures.

Methods and Material

The patients with a diagnosis of febrile seizure with an age range of 1-7 years who attended the clinic were included in the study. Neurologically normal and age- and sex-matched children with no history of febrile seizures were considered as controls.

Results

A total of 64 patients and 100 control subjects participated in this study. There were no significant inter-group differences in terms of sex and age of the participants (p >.05). There was no statistical difference between case and control groups for serum lymphocyte count, IgA, IgG, IgM, IgE levels, and anti-HB response (p >.05).

Conclusion

Our study demonstrated that there is no difference in humoral immunity between children with febrile seizures and control subjects with the same age range.

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.

Consequences of pilocarpine-induced status epilepticus in immunodeficient mice

Systemic injection of pilocarpine in rodents induces status epilepticus (SE) and reproduces the main characteristics of temporal lobe epilepsy (TLE). Different mechanisms are activated by SE contributing to cell death and immune system activation. We used BALB/c nude mice, a mutant that is severely immunocompromised, to characterize seizure pattern, neurochemical changes, cell death and c-Fos activation secondarily to pilocarpine-induced SE. The behavioral seizures were less severe in BALB/c nude than in BALB/c wild type mice. However, nude mice presented more tonic-clonic episodes and higher mortality rate during SE. The c-Fos expression was most prominent in the caudate-putamen, CA3 (p<0.05), dentate gyrus, entorhinal cortex (p<0.001), basolateral nucleus of amygdala (p<0.01) and piriform cortex (p<0.05) of BALB/c nude mice than of BALB/c. Besides, nude mice subjected to SE presented high number of Fluorojade-B (FJB) stained cells in the piriform cortex, amygdala (p<0.05) and hilus (p<0.001) in comparison with BALB/c mice. A significant increase in the level of glutamate and GABA was found in the hippocampus and cortex of BALB/c mice presenting SE in comparison to controls. However, the level of glutamate was higher in the brains of BALB nude mice than in the brains of BALB/c wild type mice, while the levels of GABA were unchanged. These results indicate that the brains of immunodeficient nude mice are more vulnerable to the deleterious effects of pilocarpine-induced SE as they present intense activation, increased glutamate levels and more cell death.

Lymphocytes subsets in children with febrile convulsions

In this study, lymphocytes subsets including blood CD3, CD4, CD8, CD16, CD19, and CD56 values were analyzed in children with febrile convulsion (FC) to determine whether there was the association of lymphocytes subsets in the pathogenesis of FC. The study includes 48 children with FC, and 55 healthy age matched control subjects, followed in Yüzüncü Yil University, Faculty of Medicine, Department of Pediatrics between October 2003 and June 2004. Blood CD3, CD4, CD8, CD16, CD19, and CD56 values were examined in the study and control groups. The analyses were performed in the Hematology Laboratory, Yüzüncü Yil University Faculty of Medicine, with flow cytometer device (Coulter Epics XL2, Flow Cytometer). A total of 48 children [17 girls (35.5%) and 31 boys (64.5%)], aged 6 months to 60 months (mean 22.20 +/- 13.75 months) with FC and 55 healthy children [28 girls (51%) and 27 boys (49%)], aged 6 months to 60 months (mean 28.87 +/- 17.04 months) were included in the study. When compared with the control group, the study found significantly decreased blood CD3 and CD4 values in the study group (p <.05). However, there was not significant difference in CD8, CD16, CD19, and CD56 values between the control and study groups (p >.05). When comparing the children with and without positive family history for FC, the study did not find any difference for all CD values between the groups (p >.05). Similarly, there was not significant difference in CD values between the children with simple and complex FC (p >.05). The findings suggested that decreased blood CD3 and CD4 values might be responsible for the infections connected with FC or that they might be related to the pathogenesis of FC in some children.

Long-term kindled seizures induce alterations in hematopoietic functions: role of serum leptin

Recent studies conducted in our laboratory have demonstrated marked increases in both serum leptin levels and colony numbers in bone marrow progenitor cells following long-term kindled seizures in rats. The present study sought to determine whether such changes in hematopoietic functions following kindling are linked to increased serum leptin levels. Kindled stage V seizures were induced for 30 days in Sprague-Dawley rats by stimulation of the basal complex of amygdala. The results revealed colony numbers in colony forming units-granulocyte/macrophage (CFU-GM) cultures from kindled rats increased significantly, an effect that was blocked by the presence of an anti-leptin antibody. The results further demonstrated that the addition of serum obtained from kindled rats to CFU-GM cultures from control rats significantly increased the numbers of colonies relative to non-serum added cultures. Moreover, the proliferative effects of serum from kindled rats were also blocked by adding an anti-leptin antibody. These findings were confirmed from the observations that the long isoform of the leptin receptor, which is capable of signal transduction, was present only in kindled, but not in control rats. Thus, the results provide evidence that the hematopoietic changes observed following long-term kindling are directly associated with elevated serum leptin levels.

Amygdaloid kindled seizures can induce functional and pathological changes in thymus of rat: role of the sympathetic nervous system

The present study sought to determine the effects of long-term kindled seizures of the basal amygdala upon immune function in rat, utilizing the thymus, as a principal target for study. Histopathology from kindled Sprague-Dawley rats revealed the presence of epithelial cell thymoma in 70% of these rats. The results revealed an increased rate of apoptosis and proliferation in thymic epithelial cells. Analysis of thymocytes indicated a decrease in the ratio of CD4 to CD8 positive T cells and reduced proliferative response to T-cell mitogens. To determine whether these effects were mediated through the sympathetic nervous system, animals were treated with guanethidine, which blocked the development of epithelial cell thymomas, while mifepristone treatment, employed to determine the possible role of the hypothalamic-pituitary axis, was ineffective in attenuating thymoma development. Thus, the present study demonstrated that functional and pathological changes in the thymus during kindled seizures are mediated through the sympathetic nervous system.

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.