HLA antigens and idiopathic epilepsy

A community-based case-control study of prevalence and pattern of cognitive impairments in patients with epilepsy residing in South-Eastern Nigeria

BACKGROUND

Epilepsy is the commonest neurological disorder encountered in Sub-Saharan Africa. The quality of life of patients with epilepsy (PWEs) is adversely affected by cognitive impairments.

AIM

This study investigated the prevalence and pattern of cognitive impairments in PWE in Ukpo community located in a South-Eastern state in Nigeria using Community Screening Interview for Dementia (CSID) and a computer-assisted cognitive test battery (FePsy).

METHODS AND PATIENTS

Fifty-one PWEs were studied and compared with 51 age-, sex-and level of education-matched healthy controls. Diagnosis of epilepsy was confirmed clinically with eye-witness corroboration. Sociodemographic data and information on epilepsy variables were obtained with the aid of a questionnaire. Cognitive domains assessed include language, memory, orientation, attention, psychomotor speed and constructional praxis.

RESULTS

The prevalence rate of cognitive impairment using total CSID score was 19.6%. Analysis of CSID scores revealed significant impairment in language (17.6%), memory (29.4%), orientation (15.7%), attention (7.8%) and constructional praxis (15.7%) compared to healthy controls. A similar pattern was observed with FePsy but with better sensitivity indices for detecting cognitive impairment.

CONCLUSION

This study indicated significant prevalence rate of cognitive impairment among treatment-naïve PWE with profound affectation of memory, mental speed and language. In addition, the FePsy was found to be more sensitive and specific in assessment of cognitive function in PWE.

[Celiac disease, cerebral calcifications and epilepsy syndrome]

The syndrome of coeliac disease, epilepsy and cerebral calcifications is a rare complication of coeliac disease. The pathological changes consist in a patchy pial angiomatosis and resemble those of Sturge-Weber syndrome, whose variant without port-wine angioma must be ruled out. Typical course includes three stages leading to a severe encephalopathy. However, the mental impairment is extremely variable. The pathogenetic process is so for unknown; main clues involve a chronic folic acid deficiency or a HLA-related autoimmune disorder. Treatment requires early gluten-free diet and anti-epileptic drug.

The phenotypic spectrum related to the human epilepsy susceptibility gene "EJM1"

Linkage studies of families ascertained through patients with juvenile myoclonic epilepsy (JME) suggest that an HLA-linked susceptibility gene on chromosome 6, designated "EJM1," predisposes to a group of idiopathic generalized epilepsies (IGEs) comprising JME, juvenile absence epilepsy (JAE), childhood absence epilepsies (CAE), and epilepsies with generalized tonic-clonic seizures (GTCS). To explore the EJM1-related phenotypic spectrum, we conducted linkage studies with HLA-DQ alpha restriction fragment length polymorphisms in 44 families ascertained through patients with CAE or JAE. Our results for the entire group of families provide evidence against a major susceptibility locus for idiopathic absence epilepsies and broader spectra of IGEs in the HLA region. Lod scores less than -2 were obtained for a region from 10 cM up to 23 cM on either side of the HLA-DQ alpha locus, depending on the assumed trait model. Suggestive evidence for linkage was found only for a subgroup of families with JME patients assuming an autosomal dominant mode of inheritance with 70% penetrance. A maximum lod score was obtained when family members with JME, JAE, CAE, and idiopathic GTCS were included into the affection status. Our results demonstrate that (1) the genetic susceptibility to idiopathic absence epilepsies and broader spectra of IGEs is heterogeneous, (2) the gene effect of EJM1 depends on the familial genetic background, and (3) EJM1 confers genetic susceptibility to idiopathic absence epilepsies and broader spectra of IGEs in the presence of family members with JME.

Serologic HLA typing in cryptogenic Lennox-Gastaut syndrome

Serologic HLA typing was performed on 12 patients with cryptogenic Lennox-Gastaut syndrome and compared to a normal control group of 1661 Caucasians. In the Lennox-Gastaut group we found a significant increase in the frequency of DR5 antigen (55%, chi 2 = 5.6), and an indication of a decrease in the frequency of DR4 antigen (0%, chi 2 = 3.0) as compared with controls (20% and 28%, respectively). No significant differences existed in the frequencies of HLA-A, B, and C antigens between the Lennox-Gastaut group and the controls. These findings contribute to the hypothesis that immunogenetic mechanisms may play a role in triggering or maintaining cryptogenic Lennox-Gastaut syndrome.

Thalamocortical oscillations in the sleeping and aroused brain

Sleep is characterized by synchronized events in billions of synaptically coupled neurons in thalamocortical systems. The activation of a series of neuromodulatory transmitter systems during awakening blocks low-frequency oscillations, induces fast rhythms, and allows the brain to recover full responsiveness. Analysis of cortical and thalamic networks at many levels, from molecules to single neurons to large neuronal assemblies, with a variety of techniques, ranging from intracellular recordings in vivo and in vitro to computer simulations, is beginning to yield insights into the mechanisms of the generation, modulation, and function of brain oscillations.

Celiac disease, posterior cerebral calcifications and epilepsy

Ten patients (5 males) affected by epilepsy with cerebral calcifications of unknown etiology mainly located in the posterior regions were subjected to a battery of tests including an intestinal biopsy. Our aim was to establish whether or not the patients also suffered from celiac disease. Celiac diseases was found in 6 patients. This result and the individual cases reported in the literature suggest that this triad of diseases (celiac disease, posterior cerebral calcifications and epilepsy) are casually related. The same HLA phenotype was found in all 10 patients, i.e., including the cases without celiac disease, suggesting an underlying disorder of the immune system. Our results emphasize that particular attention should be paid to a search for celiac disease in all patients with epilepsy and posterior cerebral calcifications.

Effects of carbamazepine and valproate on immunological assessment in young epileptic patients

Serum immunoglobulin levels and peripheral blood lymphocyte subsets were determined in 25 epileptic children treated with anticonvulsant drugs [carbamazepine (CBZ) or sodium valproate (VPA)], 17 untreated patients and 18 healthy subjects. The treated and untreated patients did not differ significantly from the controls with respect to the mean IgA, IgG, IgM values or lymphocyte subsets. The patients on carbamazepine had lower serum concentrations of IgG (though not significantly lower) than the untreated patients and children on valproate. OKT8 subset, in absolute terms and as a percentage of total lymphocytes, was significantly higher in generalized than in partial epilepsy, but this was probably due to the antiepileptic treatment. We found a sex difference in serum immunoglobulins (Ig M, IgG) in the epileptic group. Our data do not seem to argue for major changes in immune status related to clinical type of epilepsy or to VPA or CBZ treatment.

HLA study of 21 families with two or more members affected by febrile convulsions

21 Italian families with at least two members who had had febrile convulsions (FC) were HLA-typed for class I antigens. A total of 49 subjects and 43 close relatives (parents or sibs) were examined. No single antigen or haplotype was statistically more frequent among pooled FC subjects. The study, however, is not conclusive regarding a relationship between FC and HLA region because of the possible genetic heterogeneity of proneness to FC. In a significant proportion of cases two FC affected sibs had unaffected parents: besides the models of inheritance so far proposed for this pathology, the involvement of two complementary dominant factors was also considered. The report includes uncommon cases: a family where one FC affected parent transmitted the same HLA haplotype to all three affected sibs; two more families, with both parents and progeny affected by FC. The HLA typing of all members of these unusual families, although not furnishing relevant information at present, may be of value to other investigators.

HLA antigens, epilepsy and cytomegalovirus infection

Thirty-one epileptic patients, selected from among 900 children with previous febrile convulsions and subsequent epilepsy, were typed for HLA antigens. In 16 of the 31 patients CMV was isolated from the urine shortly after the appearance of spontaneous fits; in the remaining 15 patients the virus was never detected. All the examined children were typed for 14 HLA-A, 23 HLA-B, 7 HLA-C and 9 HLA-DR specificities, and compared with a group of healthy subjects. The HLA-A11 antigen was present in 25% of the children with chronic CMV infection and epilepsy, and absent in patients with epilepsy but without CMV infection (p less than 0.02). The possibility that the A11 antigen is a marker of the predisposing genes for CMV infection in children with epilepsy following FC is proposed.

The distribution of HLA-A,B, DR antigens in Chinese myasthenia gravis

The association of HLA antigens with Myasthenia Gravis (MG) in many different races is well known. In this study, HLA-A, B and DR antigens were typed on 65 Chinese MG and 232 controls for HLA-A, B and 61 for DR antigens. A2 and DRw9 increased significantly in patients with MG (p less than 0.025 and p less than 0.05 respectively). DR2 and DR4 had the opposite influence (both p less than 0.005). Several alleles were shown to have relatively high values of P D/A and relative risk but low P A/D and E.F, which suggests the marker heterogeneity of MG. Comparisons of clinically different types of MG, variations of the age of onset and thymic pathology did not show any statistically significant difference in HLA distributions. The clinical implications were discussed.

Immunological and genetic studies in primary generalized corticoreticular epilepsy

Serum immunoglobulin and HLA investigations were carried out in 21 probands with primary generalized corticoreticular epilepsy (PGCE) and in 26 of their first degree relatives. The mean serum levels of IgG, IgA and IgM in the epileptic probands were not significantly different from controls. In the relatives, however, the mean serum levels of IgA and IgM were significantly decreased as compared to controls. With respect to HLA investigations, the frequencies of 63 HLA specificities determined and of 5 most commonly occurring haplotypes were not significantly different in the experimental groups as compared to controls. These findings are in agreement with a previous HLA investigation of PGCE but are in contrast with a similar study of partial epilepsy. It is suggested that the contrasting HLA findings between PGCE and partial epilepsy may reflect underlying differences in the etiology of these disorders.