Made available in DSpace on 2016-08-10T10:39:10Z (GMT). No. of bitstreams: 1 THYAGO PEDROSA MAGALHAES.pdf: 2261259 bytes, checksum: 42a1ba331ec79afdea4d0071a56fca2c (MD5) Previous issue date: 2015-03-10 / Multiple sclerosis is a chronic inflammatory disease of the central nervous system, characterized by demyelination and neuronal degeneration, a major cause of disability in young. Subjects an autoimmune response against neuronal auto antigen, with destruction of the myelin sheath, is observed in individuals with genetic predisposition exposed to certain environmental factors. Among the genetic factors, studies suggest a complex interaction between the alleles of the human leukocyte antigen (HLA-DRB1*1501 and DQB1*0602) and the risk of developing the disease. The allele DRB1 * 1501 was associated with the disease in Caucasian patients in North America and Northern Europe, and the DQB1*0602 allele in Caucasians of Northern Europe and African descendant. The aim of this study was to conduct a systematic review and a meta-analysis of studies that investigated the contribution of DRB1*1501 and DQB1*0602 in the risk of developing MS in different populations of the world. A systematic review and meta-analysis were performed on the main publications in the electronic database of PubMed, by using the terms "HLA" "MULTIPLE SCLEROSIS", "DR" "DQ" and "HLA" "MULTIPLE SCLEROSIS" and "BRAZIL "resulting in a total of 181 articles. After reading the articles, 18 met the inclusion criteria and were selected for review. Based on the results it was possible to conclude that the two alleles are more common in MS patients than in controls, with the allele DRB1*1501 more frequent in European and Caucasian populations and the DQB1 * 0602 with a distribution more heterogeneous in populations. The results obtained by the meta-analysis showed a statistically significant association between DRB1 * 1501 and DQB1 * 0602 allele and the risk of developing multiple sclerosis (OR combined DRB1 * 1501 = 2.934, 95% CI: 2.154 to 3.998, p <0, 0001 and DQB1 * 0602 combined OR = 2.906, 95% CI: 2.167 to 3.896, p <0.0001). / A Esclerose Múltipla é uma doença inflamatória crônica do sistema nervoso central, caracterizada por desmielinização e degeneração neuronal, sendo uma importante causa de incapacidade em jovens. Decorre de uma resposta autoimune contra autoantígenos neuronais, com destruição da bainha de mielina em indivíduos com predisposição genética, expostos a determinados fatores ambientais. Dentre os fatores genéticos, estudos apontam para uma interação complexa de alelos do Antígeno Leucocitário Humano (HLA-DRB1*1501 e DQB1*0602), e o risco de desenvolver a doença. O alelo DRB1*1501 foi associado à doença em pacientes caucasianos na América do Norte e Norte da Europa e o alelo DQB1*0602 em caucasianos da Norte da Europa e afrodescentes. O objetivo do estudo foi realizar uma revisão sistemática e meta-análise sobre os estudos que investigaram a contribuição dos alelos DRB1*1501 e DQB1*0602 no risco de desenvolver EM nas diversas populações do mundo. Uma revisão sistemática e uma meta-análise foram realizadas acerca das principais publicações encontradas na base de dados eletrônicas do PUBMED utilizando os termos HLA MULTIPLE SCLEROSIS , DR DQ e HLA MULTIPLE SCLEROSIS e BRAZIL , resultando em um total de 181 artigos. Após a leitura dos artigos, 18 preencheram os critérios de inclusão e foram selecionados para a revisão. Com base nos resultados obtidos dos artigos foi possível concluir que os dois alelos avaliados são mais frequentes em pacientes com Esclerose Múltipla do que em controles, sendo o alelo DRB1*1501 mais comum nas populações europeias e caucasianas e o alelo DQB1*0602 com uma distribuição mais heterogênea nas populações. Os resultados obtidos pela meta-análise demonstraram associações estatisticamente significativas entre os alelos DRB1*1501 e DQB1*0602 e o risco de desenvolver Esclerose Múltipla, (OR combinada DRB1*1501= 2,934, 95% IC: 2,154 3,998, p < 0,0001 e OR combinada DQB1*0602 = 2,906, 95% IC: 2,167 3,896, p < 0,0001).

Background: The major histocompatibility complex (MHC) molecules play an important role in the immune response regulation and in the maintenance of the immune homeostasis. Regulation of their expression is therefore a key factor influencing the adaptive immune response. DNA methylation of gene regulatory regions is one of the mechanisms of gene expression control that affects the accessibility of DNA to transcription factors. Ageing is connected with changes in DNA methylation and increased predisposition to autoimmune diseases in older age could be associated with changes in MHC class II genes methylation. Aims: The aim of this diploma thesis is to analyze the methylation profile of DQA1 and DQB1 genes regulatory regions and to compare its differences between the generations and between individual alleles. The next aim is to compare DQA1 mRNA expression between the generations and between single alleles. Methods: DNA and RNA were isolated from blood of three age group donors. DNA was converted by the bisulfite treatment and regulatory regions of HLA class II genes were amplified and cloned into bacteria. Positive clones were sequenced and then analyzed. RNA was reverse transcribed and its expression level was determined by real-time PCR. Results: Statistically significant differences were found by...

Background: Type 1 diabetes mellitus is a multifactorial disease caused by beta cell destruction of Langerhans pancreatic islets. From the genetic aspect the main predisposition lays on HLA class II genes (40 - 50%), molecules of which present exogenous peptides to CD4+ T lymphocytes. Enviromental factors play a crucial role in the etiopathogenesis of T1DM. Through epigenetic regulation (e.g. DNA methylation) the genetic and enviromental factors communicate. The level of methylation in the regulatory regions can significantly affect expression of these genes. Aims: The aim of the diploma thesis was to define methylation profile of HLA DQB1 alleles in type 1 diabetes mellitus patients and determine their expression. Methods: The genotyping of HLA class II genes (HLA-DRB1, HLA-DQA1, HLA-DQB1) was performed using sequence specific primers. DNA was treated with sodium bisulfite, regulatory region of HLA DQB1 was amplified and cloned into E.coli, strain DH5α/XL1-Blue. Positive clones were sent for sequencing and results analyzed. RNA was transcribed to cDNA by reverse transcription and the level of expression was analyzed by quantitative PCR. Results: Statistically significant differences were found in total methylation of DQB1*0201 and *0302 alleles in the B section of DQB1 gene. Difference in...

Introduction: Glycoproteins of the major histocompatibility complex (MHC) are an irreplaceable part of immune response regulation and immune homeostasis maintenance. The regulation of the expression plays an important role in adaptive immune response. Recently, DNA methylation in regulatory areas, crucial for DNA availability to transcription factors, is one of the most researched mechanisms of this type of regulation. The DNA methylation is, among others, related to the aging processes. Increased predisposition age-related immunosenescence in higher age could result from the changes in methylation status of regulatory areas of MHC class II genes. Aims: The aim of this thesis is to analyze the methylation status of regulatory areas of DQB1 gene and to compare the differences between generations and specific alleles. The differences in the levels of DQB1 gene mRNA transcription between generations and specific alleles is also compared. Methods: Both DNA and RNA were isolated from blood samples obtained from donors of three different age groups. DNA was genotypized and modified by bisulfite conversion. The regulatory areas of DQB1 genes were then amplified and subcloned into bacteria. The positive clones were selected and subjected to DNA methylation analysis. RNA was reverse transcribed into cDNA...