Immunogenetic predisposing factors for mesial temporal lobe epilepsy with hippocampal sclerosis

• Published in: International journal of neuroscience 2018-04, Vol.128 (4), p.305-310
• Main Authors: Leal, Bárbara, Chaves, João, Carvalho, Cláudia, Bettencourt, Andreia, Brito, Cláudia, Boleixa, Daniela, Freitas, Joel, Brás, Sandra, Lopes, João, Ramalheira, João, Costa, Paulo P., da Silva, Berta Martins, da Silva, António Martins
• Format: Article
• Language: English
• Subjects: Adolescent; Adult; Aged; Case-Control Studies; Causality; cytokines; Epilepsy; Epilepsy, Temporal Lobe - complications; Epilepsy, Temporal Lobe - genetics; Female; genetics; Genotype; Hippocampus - pathology; HLA-DRB1 Chains - genetics; Humans; Immunogenetics - methods; Interleukin-1alpha - genetics; Male; Middle Aged; MTLE-HS; neuroinflammation; Polymorphism, Single Nucleotide - genetics; Sclerosis - etiology; SNPs; Tumor Necrosis Factor-alpha - genetics; Young Adult
• ISSN: 0020-7454; 1543-5245; 1563-5279
• DOI: 10.1080/00207454.2017.1349122

Purpose: Neuroinflammation appears as an important epileptogenic mechanism. Experimental and clinical studies have demonstrated an upregulation of pro-inflammatory cytokines such as IL-1β and TNF-α, in mesial temporal lobe epilepsy with hippocampal sclerosis (MTLE-HS). Expression of these cytokines can be modulated by polymorphisms such as rs16944 and rs1800629, respectively, both of which have been associated with febrile seizures (FS) and MTLE-HS development. The human leukocyte antigen (HLA) system has also been implicated in diverse epileptic entities, suggesting a variable role of this system in epilepsy. Our aim was to analyse the association between immunogenetic factors and MTLE-HS development. For that rs16944 (-511 T>C, IL-1β), rs1800629 (-308 G>A, TNF-α) polymorphisms and HLA-DRB1 locus were genotyped in a Portuguese Population. Methods: We studied 196 MTLE-HS patients (108 females, 88 males, 44.7 ± 12.0 years, age of onset = 13.6 ± 10.3 years, 104 with FS antecedents) and 282 healthy controls in a case-control study. Results: The frequency of rs16944 TT genotype was higher in MTLE-HS patients compared to controls (14.9% in MTLE-HS vs. 7.7% in controls, p = 0.021, OR [95% CI] = 2.20 [1.13-4.30]). This association was independent of FS antecedents. No association was observed between rs1800629 genotypes or HLA-DRB1 alleles and MTLE-HS susceptibility. Also, no correlation was observed between the studied polymorphisms and disease age of onset. Conclusion: The rs16944 TT genotype is associated with MTLE-HS development what may be explained by the higher IL-1β levels produced by this genotype. High IL-1β levels may have neurotoxic effects or imbalance neurotransmission leading to seizures.