Studies on lymphocyte subpopulations and NK cell activities in epileptic patients

Association between NKG2/KLR gene variants and epilepsy in Autism Spectrum Disorder

Autism Spectrum Disorder (ASD) is a set of neurodevelopmental disorders mainly characterized by repetitive, restrictive and stereotypical behaviors, and impaired communication skills. Several lines of evidence indicate that alterations of the immune system account for ASD development, including the presence of brain-reactive antibodies, abnormal T cell activation, altered cytokine levels in brain, cerebrospinal fluid and peripheral blood circulation, increased levels of circulating monocytes, and dysregulation in Natural Killer (NK) cells activity. Regarding NK cells, a lower cytotoxic activity, a higher level of activation and an increased number of these cells in individuals with ASD have been described. In 2019, a study showed that NK cells derived from patients with ASD show a characteristic pattern of NKG2C overexpression, highlighting the importance of the NK cell pathway in ASD. In fact, the study of genes related to NK cell activity has proven to be an excellent research target, both in terms of susceptibility as well as a marker for the different clinical manifestations observed in ASD individuals. Here, we evaluated the influence of KLRC2 gene deletion as well as KLRK1 rs1049174 and rs2255336 variants in a cohort of 185 children diagnosed with ASD and their respective biological parents in southern Brazil. Of note, this is the first study concerning genetic variants of the KLRC2 and KLRK1 genes in an ASD sample. The KLRC2 gene deletion (p = 0.001; pc = 0.009), KLRK1 rs1049174 (p = 0.005; pc = 0.045) and KLRK1 rs2255336 (p = 0.001; pc = 0.009) were associated with epilepsy in ASD patients. The results indicate that KLRC2 deletion, KLRK1 rs2255336, and KLRK1 rs1049174 could be involved in epilepsy manifestation in ASD patients, possibly impacting the NK dysregulation already described in ASD and epileptic patients.

Adaptive immunity cells are differentially distributed in the peripheral blood of glycine receptor antibody-positive patients with focal epilepsy of unknown cause

AIM

Glycine receptor (GlyR) autoantibodies (Ab) have been recently detected in epilepsy patients. Our study aimed to investigate the peripheral blood distribution of B and T cell subgroups responsible for antibody production to find clues supporting the distinct organization of adaptive immunity in focal epilepsy of unknown cause (FEUC).

METHOD

Seven GlyR-Ab positive and 15 GlyR-Ab negative FEUC patients and 25 age-sex matched healthy individuals were included. Peripheral blood mononuclear cells were isolated and immunophenotyped by flow cytometry.

RESULTS

There were no significant differences between CD19⁺ B, CD3⁺ T, CD4⁺ helper T, CD8⁺ cytotoxic T, and CD19⁺CD24⁺⁺CD38⁺⁺ regulatory B cell ratios among the groups. GlyR-Ab negative epilepsy patients had significantly higher CD19⁺IgD⁺CD27^- naive B cells and GlyR-Ab positive patients showed reduced percentages of CD19⁺CD38⁺CD138⁺ plasma cells than healthy controls. By contrast, GlyR-Ab positive patients exhibited significantly increased CD3⁺CD4⁺CD25^highregulatory T (Treg) cells and CD3⁺CD4⁺CD25^highCD127^low/- Treg cells and relatively increased CD19⁺IgD-CD27⁺ memory B cells without attaining statistical significance.

CONCLUSION

The increase of Tregs, which are capable of suppressing B cells, maybe a compensating countermeasure to prevent the conversion of effector B cell subgroups. Thus, our findings lend support to the involvement of adaptive immunity in focal epilepsy of unknown cause.

Interictal alterations of cytokines and leukocytes in patients with active epilepsy

BACKGROUND

Involvement of the innate immune system in the pathogenesis of epilepsies has been suggested but possible interactions between the immune system and human epilepsy remain unclear. We analyzed the interictal immuno-phenotype of leukocyte subsets and proinflammatory cytokine profiles in epileptic patients and correlated them with the epilepsy syndrome.

METHODS

101 patients with active focal or generalized epilepsy were prospectively included and compared to 36 healthy controls. Immuno-phenotype of leukocyte subsets and cytokines IL-1β, IL-6 and tnfα were measured in peripheral blood. Multivariate analyses were performed to test group differences.

RESULTS

As compared to controls, the patients showed an elevated percentage of monocytes (18.06±7.08% vs. 12.68±4.55%, p<0.001), NK cells (14.88±7.08% vs. 11.43±5.41%, p=0.019) and IL-6 concentration (3.33±3.11 pg/ml vs. 1.5±1.36 pg/ml, p=0.002). This remained true when focal epilepsies or generalized epilepsies were compared separately to controls but only focal epilepsies showed additionally a decrease in B lymphocyts (8.16±3.76% vs. 11.54±4.2%, p<0.001). Treatment with lamotrigine was associated with a higher percentage of B lymphocytes and valproate with an increased percentage of CD4(+) T lymphocytes. Therapy with levetiracetam showed a trend towards decreased CD8(+) T cell counts. No significant differences were seen between focal and generalized epilepsies and between temporal and extratemporal lobe epilepsies.

CONCLUSION

Patients with active epilepsy revealed interictal alterations of the immune system which varied among specific syndromes and were influenced by antiepileptic drug treatment.

NK and CD4+ T cell changes in blood after seizures in temporal lobe epilepsy

Immunological phenomena may affect the course of focal epilepsy. We analyzed prospectively the pre- and postictal distribution of leukocyte subsets in epileptic patients.

METHODS

Twenty-two patients (age 36.6+/-10.8 years, 50% men) with temporal lobe epilepsy were included. Distribution of leukocyte subsets and serum levels of epinephrine were measured in peripheral blood immediately and 24 h after seizures and compared to baseline values.

RESULTS

In the immediate postictal state (10+/-6 min), we observed a significant relative increase of total leukocytes (42%, p=0.0004), neutrophil leukocytes (55%, p=0.0007), total lymphocytes (45%, p=0.0019), natural killer (NK) cells (104%, p=0.0017), and epinephrine (454%, p=0.0014). CD4(+) T cells decreased by 13% (p=0.0113). These postictal changes remained significant considering only complex partial seizures (n=17). The alterations were more pronounced in patients with hippocampal sclerosis. Treatment with valproic acid (VPA) was accompanied by a greater postictal decrease of CD4(+) T cells (25% compared to 5% in patients without VPA, p=0.041) while treatment with levetiracetam (LEV) correlated with a low postictal increase of NK-like T cells (4% versus 41%, p=0.016). Twenty-four hours after the seizures the alterations had resolved.

CONCLUSION

Profound postictal changes in the immune cell composition of the peripheral blood may have been mediated by epinephrine release. The greater immune response in patients with mesial temporal lobe epilepsy due to hippocampal sclerosis may reflect a close relationship between mesial temporal structures and the sympathetic nerve system. VPA and LEV may have an impact on seizure induced immunological changes.

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.

Effects of hemispheric lateralization and site specificity on immune alterations induced by kindled temporal lobe seizures

The effects of kindled seizures elicited from sites in the left and right temporal lobes on mitogen-induced proliferation (LPS, Con A, PHA) and induction of representative TH1 (IFN-gamma) and TH2 (IL-10, IL-4) cytokines were determined in activated rat splenocytes. With reference to cell proliferation, the changes depended on the hemispheric side and location of kindling. Kindling of the left side mediated significant increase in cell proliferation by LPS. Left side kindling resulted in decreased cell proliferation by PHA. Although right side kindling showed no change when taken together, further analysis showed that the reduced proliferation by PHA was mediated when the pyriform cortex was kindled with no change from amygdaloid nuclei. Similar hemispheric polarization was observed in the production of IL-10 and IFN-gamma by Con A-stimulated splenocytes in left side kindled rats. Hence, kindled temporal lobe seizures induced changes in specific immune functions. These effects are not only lateralized but are also specific with respect to the particular region kindled. Since epileptic patients have altered immune functions, this report contributes to our understanding of this complex immune-brain cross-talk in epilepsy.

Age dependent changes in some immune system parameters and GFAP immunoreactivity in genetically absence epileptic rats

The present study evaluated the contribution of some peripheral immunological parameters and GFAP immunoreactivity at different ontogenic stages of non convulsive absence epilepsy in WAG/Rij rats. For this, 2- and 6-month-old WAG/Rij rats, and the aged-matched control Wistar-albino rats were used. After collecting blood samples from all rats, the CD3 + (T cells), CD4 + (T helper), CD8 + (T cytotoxic), CD19 + (B cells) and CD25 + (IL-2 receptor, active T cell) cell ratios were determined by indirect immunofluorescence method and, serum IgG, IgA, IgM levels were evaluated by using rat radial immunodiffusion plates. After decapitation, brains were dissected and, GFAP staining was evaluated in the areas of caudate nucleus, thalamus, hippocampus, amygdala and cerebellum by immunohistochemistry. CD3 + cells and IgM levels increased with age in WAG/Rij rats. However, GFAP + astrocytes were decreased with age in caudate nucleus, thalamus, amygdala, and cerebellum of WAG/Rij rats. In the genetically absence epileptic rats, the humoral immunity was found to be affected more and activated by age. Additionally, astrocytes in thalamus and caudate nucleus that are the most important areas in the pathogenesis of absence epilepsy, were found to be decreased with age in WAG/Rij rats. From the results, it can be concluded that peripheral immunological parameters together with astrocytic activity may participate in the etiopathogenesis of absence epilepsy.

Chronic staphylococcal scalded skin syndrome

Staphylococcal scalded skin syndrome (SSSS), not previously recorded as a chronic disease, persisted for 2 years in a 50-year-old woman with epilepsy and cerebellar ataxia. Lesions initially suggestive of erythema multiforme and toxic epidermal necrolysis evolved over 2 years into those typical for SSSS, with extensive erosions and subcorneal blisters, showing an epidermal split at the granular cell layer. Exfoliatin A-producing phage I-III Staphylococcus aureus, previously linked only to acute mild adult cases of SSSS, was cultured from purulent discharge in the patient's eyes, ears and open skin lesions. The roles of epilepsy and antiepileptic medications are discussed as possible predisposing factors.

[Studies on double-labelling method for determination of T lymphocyte subpopulations]

In order to determine the concurrent expression of DR and CD antigen of T lymphocyte surface markers, the fluorescence-rosette double-labelling technique was developed by employing monoclonal antibody against HLA-DR and sensitized sheep erythrocytes with OKT series of monoclonal antibodies against cell surface antigen. Its reliability was evaluated by comparison with two-step isolating technique for determining DR antigen of activated T lymphocyte subsets in 30 healthy volunteers. The result showed there was no statistic difference between results determined with two methods. The double-labelling technique was characterized by its samplity, no injury for cellular activity and ability for analysing the expression of the single antigen and double antigens on cell surface concurrently.

Immunomodulation of musk-moxa-string therapy in patients with scrofula

The effects of musk-moxa-string therapy on the immune system in man were investigated in 39 patients with scrofula. Before treatment, the numbers of peripheral blood (PB) CD3+ and DC4+ cells and the ratio CD4+/CD8+ were found to be lower in patients with scrofula than in normal subjects, while those of B cells and DR+ cells were higher. Response of peripheral blood mononuclear cells (PBMC) to phytohemagglutinin (PHA) diminished in patients with scrofula. At month 2-6 of musk-moxa-string therapy the number of PB CD8+ cells showed slight diminution along with significant increases in CD3+ and CD4+ cells and CD4+/CD8+ ratio in total lymphocytes (P less than 0.001). In vitro a marked increased blastogenic response to mitogen stimulation with PHA was observed in PBMC of patients with scrofula after treatment (P less than 0.001). In contrast, B lymphocytes, monocytes, DR+ cells and blastogenic response to concanavalin A and pokeweed mitogen were not influenced by musk-moxa-string therapy.

Peripheral blood and bone marrow lymphocyte subsets in patients with multiple myeloma

A panel of monoclonal antibodies (McAb) from the Wu series was used to characterize lymphocyte subsets of peripheral blood (PB) from 9 patients with multiple myeloma (MM) by means of indirect immunofluorescence assay. In 7 of these patients bone marrow (BM) cells were also studied. Abnormal distribution of T lymphocyte subsets was observed in these patients, and the alterations were quite similar in both PB and BM. A significant increase in the proportion of WUT8+ cells (P less than 0.001) and a reduced WuT4/WuT8 ratio (P less than 0.001) were found in patient group. In both PB and BM of patients, WuT10+ cell counts were significantly higher than normal (P less than 0.001). There was a good correlation between BM WuT10+ cells and BM myeloma cells (r = 0.76, P less than 0.05), whereas no correlation was found between PB WuT10+ cells and BM myeloma cells. The significance of abnormal T-cell subset distribution and elevated WuT10+ cells in MM is discussed.