Increased Levels Of HMGB1, IL-2, IL-6 In The Serum Of Epileptic Children And Its Significance

Background and Objective:Epilepsy is a chronic nervous system disease characterized with abnormal synchronous repeated discharge of brain neurons, and it is a serious hazard to human health. The pathogenesis of epilepsy is not yet fully clear. 70% of these patients after formal antiepileptic therapy can be recovered, and about 30% patients after specific treatment with first-line antiepileptic drugs(AEDs) still cannot be effectively controlled and become intractable epileptic seizures, patients with repeated epileptic seizures will cause development retardation and even backwards, it is a heavy burden to the patients themselves, their families and society. Currently intractable epilepsy become one of the urgent problems in medicine, which because the pathogenesis of intractable epilepsy remains unclear, we cannot seek new treatment approach according to the key mechanism. According to last decade’ clinical and experimental studies, brain inflammation is an intrinsic feature of the hyperexcitable pathologic brain tissue in pharmacoresistant epilepsy of different etiology. Many studies indicate that brain inflammation is not a mere epiphenomenon of the pathologic tissue. Brain inflammation contributes to determine seizure threshold in susceptible brain regions. More and more animal experiment and clinical research of epilepsy confirmed epilepsy has a correlation with immunity and inflammation. What’s more, with the deepening research on epilepsy of the domestic and foreign scholars confirmed that epilepsy exists immune dysfunction, including humoral immunity and cellular immune dysfunction, but the role of immunity and inflammation in patients with epilepsy is still unclear. We strengthen research on the correlation between the immune inflammatory response and epilepsy to find new targets for epilepsy treatment, seeking new breakthrough for epilepsy treatment.High mobility group protein 1 is non-histone chromosomal binding protein exists in eukaryotic cells especially nucleus, widely existing in the lymphoid tissue, brain, liver, heart, spleen, kidney cells, mainly exists in the nucleus. Studies have shown that HMGB1 can be secreted to outside the cell by macrophages, monocytes, pituitary cells and so on induced by endotoxin lipopolysaccharide(LPS), tumor necrosis factor alpha(TNF-α). HMGB1 can activate toll-like receptors 4 of the cell surface, a series of reactions relying on myeloid cells differentiation factor 88(My D88) related signal channel eventually lead NF-kappa B into the nucleus,and play the role of transcription regulation, activating IL-1, IL-6, IL-12, TNF alpha and INF- gamma and causing inflammation cytokines gene expression. Studies confirm that HMGB1 is involved in pathological processes of cerebral ischemia, cerebral injury, intracranial infection, septicemia, pancreatitis, infection of the respiratory system diseases and so on. Giving HMGB1 antibodies that can reduce inflammation caused by these diseases, and instead giving restructuring HMGB1 can aggravate the inflammatory response. In the epilepsy model can see the above phenomenon now.IL-2, IL-6 are important cytokines, IL-2 has a wide range of biological activity produced by activated CD4+ and CD8+ cell, and it’s the group factors of all T cells subgroups and can promote the proliferation of activated B cell. So IL-2 is important factor regulating the immune response. IL-6 has many kinds of biological activity such as inducing the activation of B cell, mononuclear cell differentiation and inducing IL-2 and IL-2 receptor expression, etc. IL-6 has a important role in immune response. study have found that serum level of IL-6 in epilepsy group were higher than that of normal control group. What’s more, seizure incubation period is shorten, the threshold reduced, the time of discharge and behavior at a time extended of epileptic mouse injected with restructuring IL-2. Use IL-2 antibodies or their receptors antibodies can obviously reduce epileptic seizures. All these instruct IL-2 and IL-6 may participate the epileptogenesis.IL-2, IL-6, HMGB1 are important cytokines participating immune inflammation response. The role of HMGB1 in epilepsy research at home and abroad is less, and it’s very rare in reports in children with epilepsy. And the study of IL-2, IL-6 are relatively more, but less in children’s study. In order to have a further study in immune relations with epilepsy, this experiment will detect IL-2, IL-6, HMGB1 changes in the serum of children with epilepsy, to have further study on the relationship between the inflammatory response and the pathogenesis of epilepsy, seeking new targets for the treatment of epilepsy.MethodsEighty-five children aged 6months to 12 years with idiopathic generalized or partial epilepsy diagnosed in the pediatric inpatient department as the experimental group. They are under the 2010 ILAE(International League Against Epilepsy) and IBE(International Bureau for Epilepsy) making recommendations of seizures and epilepsy syndrome diagnosis classification. They are diagnosed of idiopathic epilepsy that combined with clinical manifestations, past medical history and personal history, family history, electroencephalogram(EEG) and brain MRI. Ruled out patients with central nervous system infection, cerebral trauma, cerebral infarction, cerebral hemorrhage, brain placeholder or genetic metabolic diseases causing secondary epilepsy, and ruled out patients taking hormone and immune inhibitors and recent infections. Experimental group are separated into 3 subgroups(frequent epilepsy subgroup 1, status epilepicus subgroup 2, and the others subgroup 3). Obtaining fasting veinal blood 2ml after seizure onset within 12 hours. And then let it stand at room temperature for 30 minutes, and centrifuge 20 minutes(3000 r/min), collecting the serum and keeping them in the-80℃ refrigerator. Methods of specimens of normal control group are the same. Using enzyme linked immunosorbent assay(ELISA) to investigate the levels of IL-2, IL-6, HMGB1 in the serum. The operating method in accordance with the specifications strictly and enzyme standard instrument in 450 nm wavelength measures optical density(OD value) of each hole. All data statistical method applied with SPSS17.0 software processing, observing difference of the level change of IL-2, IL-6 and HMGB1 between epilepsy group and normal control group and between subgroups and their correlation.ResultsIn our study, the levels of IL-6 in the serum of frequent epilepsy subgroup, status epilepicus subgroup, the others and the controls are 14.559(0.484)ng/L, 14.752(0.442)ng/L, 11.981(0.683)ng/L, 8.056(1.072)ng/L respectively, the levels of IL-2 in different group is 855.924(74.459) ng/ml, 918.535(68.079)ng/ml, 737.546(119.236)ng/ml, 515.649(84.873) ng/ml, and the levels of HMGB1 are 8.621(0.642)ng/ml, 8.987(0.736)ng/ml, 7.870(0.407)ng/ml, 4.221(0.904)ng/ml respectively. The level of IL-2, IL-6, HMGB1 of experimental groups are higher than the controls, extremely the level of IL-2, IL-6, HMGB1 of frequent epilepsy subgroup and the status epilepicus subgroup are higher than the subgroup 3, but the level of IL-6, HMGB1 between subgroup 1 and subgroup 2 has no obvious difference, the level between subgroup 1 and subgroup 2 has an obvious difference. The level of IL-6 has a positive correlation with the level of HMGB1(r2=0.577, P<0.05), the level of IL-2 has a positive correlation with the level of HMGB1(r2=0.59, P<0.05). In this experiment, the type of seizure、use anti-epileptic drugs or not,the levels of IL-2, IL-6, HMGB1 in the serum of epileptic children don’t have obvious difference. Conclusions:1.The degree of inflammation in seizures may be positively related to the severity of seizures2.HMGB1 acts as a proinflammatory cytokines in the epileptogenesis through the regulation of IL-2, IL-6 and other cytokines release and initiates, maintains and amplifies of inflammatory response, therefore HMGB1 inhibitor may have a role to control intractable epilepsy and seek a new therapeutic target.