Diss. (sammanfattning) Stockholm : Karolinska institutet, 2007. / Härtill 4 uppsatser.

Diss. (sammanfattning) Stockholm : Karolinska institutet, 2007. / Härtill 4 uppsatser.

The Epstein Barr virus (EBV) is studied in this project to establish a latency compared with the infected organism and to a number of pathophysiologies. Its oncogenic potential associated with serological evidence of the presence of the viral agent for cancer and also for autoimmune diseases such as rheumatoid arthritis and lupus erythematosus. Detection processes are necessary and have attracted scientific interest in recent decades, and they are important analytical tools used for clinical diagnosis, disease control, physiological changes, among others. Through the above two genosensors were developed to the specific recognition of EBV by electrochemistry. The peak oxidation of ethidium bromide (EB) in graphite electrodes modified with poly (4-ATP) and the peak tetramethylbenzindine (TMB) reduction, as a new indicator of hybridization oligonucleides, in graphite electrodes modified with poly (AP-4) were designed and evaluated these platforms. Analysis of Surface Plasmon Resonance (SPR) and Atomic Force Microscopy (AFM) were used to complement the study to theoretical and practical application. The prospect of this project is the application in the diagnosis of infection caused by the Epstein-Barr virus (in serum samples, saliva and urine) non-invasively in rapid tests evaluating their sensitivity, selectivity, specificity, speed and low cost. / O vírus Epstein Barr (EBV) é estudado neste projeto por estabelecer uma relação de latência com o organismo infectado e a uma série de fisiopatologias. Seu potencial oncogênico está relacionado às evidências sorológicas da presença do agente viral em neoplasias e também às doenças autoimunes como a Artrite Reumatoide e o Lúpus Eritematoso. Processos de detecção são necessários e têm despertado interesse científico nas últimas décadas, sendo importantes ferramentas analíticas usadas para diagnóstico clínico, controle de doenças, alterações fisiológicas, dentre outras. Mediante o exposto, dois genossensores foram desenvolvidos visando o reconhecimento específico do EBV pela eletroquímica. O pico de oxidação do brometo de etídio nos eletrodos de grafite modificados com poli(4-ATF) e o pico de redução de tetrametilbenzindina, como novo indicador de hibridização de oligonucleotídeos, nos eletrodos de grafite modificados com poli(4-AF) foram projetados e avaliados nestas plataformas. Análises de Ressonância de Plasmon de Superfície (SPR) e Microscopia de Força Atômica (AFM) foram utilizadas para complementar o estudo a fim de fundamentação teórica e prática. A perspectiva deste projeto é a aplicação no diagnóstico da infecção causada pelo vírus Epstein-Barr (em amostras de soro, saliva e urina) de forma não invasiva em testes rápidos avaliando sua sensibilidade, seletividade, especificidade, rapidez e de baixo custo. / Doutor em Genética e Bioquímica

Orientador: Maria Marluce dos Santos Vilela / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Ciencias Medicas / Made available in DSpace on 2018-08-10T20:47:23Z (GMT). No. of bitstreams: 1 Toro_AdyleiaAparecidaDalboContrera_D.pdf: 3459466 bytes, checksum: a2a86bc660c9851dab70414f47dc5420 (MD5) Previous issue date: 2008 / Resumo: INTRODUÇÃO: A infecção pelo HIV desencadeia diversificadas e extensas alterações no mecanismo de defesa do pulmão, o que se traduz em maior número de infecções por germes habituais ou oportunistas e processos imunológicos diversos como a pneumonia intersticial linfocítica (PIL), a hiperplasia linfóide (HLP) ou neoplasias. A infecção simultânea do HIV e do EBV pode aumentar o risco de HLP/ PIL. OBS.: O resumo na integra poderá ser visualizado no link ou texto completo da tese digital / Abstract: BACKGROUND: Pulmonary Lymphoid Hyperplasia (PLH) / Lymphoid Interstitial Pneumonitis (LIP) complex is common in HIV infected children. It may reflect a particular response to HIV from a developing immune system, and is also related to exposure to Epstein-Barr virus (EBV). Note: the complete abstract is avaiable with the link or full eletronic digital theses or dissertations / Doutorado / Pediatria / Doutor em Saude da Criança e do Adolescente

O Epstein-Barr vírus (EBV) é a única espécie humana pertencente ao gênero Lymphocryptovirus. A transmissão ocorre através da saliva contaminada e geralmente ainda na infância. Nosso estudo analisou 165 amostras clínicas de pacientes, portadores de HIV, em tratamento com antiretrovirais, atendidos no Sistema Hospitalar do Sistema Penitenciário do Estado de São Paulo. Nosso enfoque foi pesquisar o EBV nas células mononucleares do sangue periférico, através das técnicas de PCR, Nested-PCR e seqüenciamento de nucleotídeos. Os resultados obtidos, indicaram que 11,51% (19) das amostras analisadas, apresentaram-se positivas para o EBV. Essas 19 amostras, foram seqüenciadas com primers específicos para a região da EBNA-1 (Epstein Barr Nuclear Antigen 1). As amostras foram alinhadas com o auxílio do DNASTAR. Ao alinharmos as amostras, encontramos uma troca de base (de G para A) em 7 amostras e essa troca não alterou a conformação da proteína EBNA-1. Na análise filogenética de nossas sequências com as depositadas no GenBank, foi possível observar dois grupos, que representam tipo 1 e o tipo 2 do EBV. 100% das amostras estudadas por nós foram identificadas como pertencentes ao grupo que caracteriza o tipo 2. Sendo assim, as 7 amostras que apresentaram a troca sugerem a origem um novo subtipo. / The Epstein-Barr Virus (EBV) is the only species to the genus Lymphocriptovirus that infects humans. One of the possible route for its transmission thought by contamined saliva and usually occurs in the childhood. This study analysed 165 clinical samples from HIV infected patients, treated by HARRT, attended in the Hospitalar System in the Penitentiary System from Sao Paulo State. The aim of this study was to search EBV in peripheral blood mononuclear cells by PCR, Nested-PCR and sequencing analysis. The results showed 11,51% of the analysed samples, positive for EBV. This samples, was sequenced with specifics primers from the EBNA-1 (Epstein Barr Nuclear Antigen 1) region. The samples were aligned by DNASTAR program. The aligned sequences showed the base conversion G to A in seven samples. This conversion caused no alteration in the EBNA-1 protein conformation. In the phylogenetic analysis the studied sequences with the sequences from GenBank was possible to observe two groups represented with type 1 and type 2 from EBV. 100% the samples studied was identified with the group characterized by the type 2 to EBV. So the seven samples showed the conversion, suggesting the origin of the one new subtype.

Orientadores: Laura Sterian Ward, Alfio José Tincani / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas / Made available in DSpace on 2018-08-24T20:17:52Z (GMT). No. of bitstreams: 1 Almeida_JacquelineFatimaMartins_M.pdf: 2198135 bytes, checksum: 94a76c347fc27e9b1fc05d077aa728a0 (MD5) Previous issue date: 2014 / Resumo: Agentes biológicos causadores de neoplasias humanas têm sido alvo de pesquisas científicas nos últimos anos, especialmente os vírus, considerados responsáveis pela causa de cerca de 20% de todos os tipos de cânceres em geral. No entanto os mecanismos pelos quais estes vírus causam tumores variam dependendo do tipo de sua espécie, da célula alvo e de fatores que concernem ao hospedeiro. Os herpes vírus, como o Herpes Simplex Virus tipo 2 (HSV-2), Epstein-Barr vírus (EBV), Citomegalovirus (CMV) e Herpesvirus Humano tipo 8 (HHV-8) têm sido associados com diversas neoplasias malignas e também com doenças autoimunes tireoidianas. O objetivo do nosso trabalho foi verificar a presença da infecção destes herpes vírus em nódulos tireoidianos benignos e malignos procurando indícios de uma possível associação com tumores tireoidianos. Foram coletadas amostras de tecido tumoral tireoidiano e soro de 153 portadores de nódulos de tireoide (136 mulheres e 17 homens, 46±15 anos) incluindo 65 tumores benignos (48 bócios, 17 adenomas foliculares e 09 portadores de doença tireoidiana autoimunes sendo 02 doenças de Graves e 07 Hashimotos) e 79 tumores malignos (78 carcinomas papilíferos e 01 carcinoma folicular). Também obtivemos 75 tecidos tireoidianos normais extraídos do lobo contralateral da lesão em 75 tumores. Foi realizada análise sorológica por ELISA para detecção de anticorpos dos herpes vírus e foi realizada análise da Carga Viral por PCR em Tempo Real. Quarenta e cinco (29,4%) pacientes (45/153) possuíam anticorpos anti-HSV2; 83,7% anti-CMV (128/153); 98% anti-EBV (150/153) e nenhum paciente possuía anticorpos anti-HHV8, o que é compatível com as estimativas esperadas na população brasileira. As concentrações de anticorpos anti-EBV foi, em média maior do que o do HSV-2 e do que o do CMV (p<0,0001). Os herpes vírus HSV-2, CMV e HHV-8 não foram encontrados em nenhum tecido tireoidiano da população estudada. No entanto, encontramos sequências de DNA do EBV em 20 amostras de tecidos tireoidianos (04 bócios, 03 DAIT e 13 CP). Embora a carga viral média fosse de 1068 cópias/µg nos casos malignos e de 374 cópias/µg nos casos benignos, esta diferença não se mostrou estatisticamente significante. Foram encontrados também 6/75 (8%) casos positivos para a infecção por EBV nos tecidos normais. A carga viral foi, em média, maior nos tumores (126,5 cópias/µg) do que em seus respectivos tecidos normais (93 cópias/µg; p=0,0207). Não houve correlação entre a presença de EBV e as características clínicas ou de evolução dos pacientes. Embora, para melhor compreensão de seus mecanismos de ação, sejam necessários novos estudos moleculares e microbiológicos, a presença da alta carga viral do EBV nos tecidos tumorais tireoidianos em relação aos tecidos normais correspondentes sugere que este vírus pode exercer um papel no desenvolvimento de nódulos tireoidianos / Abstract: Biological agents that cause human cancers have been the subject of scientific research in recent years, especially viruses considered to be responsible for the cause of about 20% of all cancers in general. Although the mechanisms of latent infection and carcinogenesis vary depending on the particular virus, target cells, and host factors. Herpesviruses, such as Human Simplex Virus type 2 (HSV-2), Epstein - Barr virus (EBV), Cytomegalovirus (CMV) and Human Herpes Virus type 8 (HHV-8) have been associated with human malignancies and also with thyroid autoimmunity. We aimed to analyze the presence of these viruses in benign and malignant thyroid nodules looking for evidence of a possible association with thyroid tumors. Serum and thyroid specimens were prospectively collected from 153 thyroid nodule patients (136 females and 17 males, aged 46±15 years) including 78 papillary thyroid cancers (PTC), 01 follicular thyroid cancer (FTC), 17 follicular adenomas and 48 goiters. We used ELISA to screen all patients for the presence of the viruses and a real-time quantitative PCR (qPCR) technique to analyze thyroid tissues viral load on antibody-positive patients. Forty-five (29.4%) patients (45/153) presented anti-HSV2 antibodies; 83.7% anti-CMV (128/153); 98% ani-EBV (150/153) e no patient presented antibodies anti-HHV8, which would be expected to be found in Brazilian population in general. In both malignant and benign groups the medians of antibodies anti-EBV were higher than HSV-2 and CMV medians (p<0,0001). There was no evidence of the presence of HSV-2, CMV and HHV-8 in the population studied. Nevertheless we found EBV¿s DNA sequences in 20 thyroid tissue samples. Even though the average malignant viral load was 1068 copies/µg in 13 cases and 374 copies/µg in 7 benign cases, there was no statistically significant difference between groups. We also found 6 (8%) positive cases for EBV viral load out of 75 normal tissues. In paired test the viral load median was higher in tumors (126.5 copies/µg) than in their respective normal tissues (93 copies/µg; p=0.0207). We did not find any association among the presence of EBV and/or its viral load and any clinical or pathological feature. Althought molecular studies are needed to a better comprehension of the mechanisms underlying the relation between EBV and thyroid nodules, the presence of high EBV copy numbers in thyroid tumors, especially in PTC cases, in comparison with normal tissues, suggests that this virus may play a role in the development of thyroid nodules / Mestrado / Clinica Medica / Mestra em Clínica Médica

Cette thèse tente d’initier un dialogue entre la philosophie de Maurice Merleau-Ponty et l’oeuvre théorique du cinéaste Jean Epstein. Située à la frontière poreuse entre la phénoménologie et l’esthétique du cinéma, elle souligne la profondeur de l’approche proposée et permise par la pensée de Merleau-Ponty, en particulier à travers les pistes ouvertes par ses notes préparatoires du cours Le monde sensible et le monde de l’expression (1953), publiées en 2011. Cette recherche adopte donc une perspective réflexive et interrogative sur la posture du phénoménologue. La première partie met en avant l’importance du rapport ambigu de la phénoménologie merleau-pontienne au langage verbal et les difficultés qu’elle rencontre pour se penser elle même en tant que fait linguistique. Cette ambiguïté se trouve à la racine d’un « besoin » virtuel d’image,mais également de certaines « résistances » à la participation active du cinéma dans la constitution du savoir.Les deuxième et troisième parties de la recherche mettent directement en place la confrontation avec la pensée de Jean Epstein. Elles se concentrent respectivement sur la notion de réversibilité, à la fois comme concept et comme procédé cinématographique; puis sur l’idée du cinéma comme « pensée » artificielle,autonome et expressive. En retraçant l’évolution de la « parole du cinéma » dans l’oeuvre d’Epstein, on découvre certaines problématiques partagées avec l’ontologie de la Chair de Merleau-Ponty. La dernière partie de la thèse reprend une série de propositions critiques de cette ontologie fondées sur des concepts émanant de l’image en mouvement. Au final, cette recherche propose de voir dans les crises internes de l’appareil conceptuel de Merleau-Ponty, une possibilité de pratiquer une philosophie du cinéma. / This thesis attempts to initiate a dialogue between Maurice Merleau-Ponty’s philosophy and the theoretical works of director Jean Epstein. Situated at the porous borders of phenomenology and visualstudies, it underlines the depth offered by Merleau-Ponty’s approach. It gives a specific attention to the newleads opened by the preparatory notes to his lessons « Le monde sensible et le monde de l’expression »(1953), published in 2011. This research adopts a reflexive and interrogative perspective towards thephenomenological « posture ». The first part insists on the importance of the ambiguous attitude of Merleau-Ponty’s phenomenology towards verbal language, and on the difficulties it encounters to conceive itself as alinguistic fact. This ambiguity gives its roots to a virtual « need » for images, but also to several« resistances » against the active participation of cinema in the constitution of knowledge. The second andthird part of the research directly instigate the confrontation with Jean Epstein’s thinking. They focus respectively on the notion of « reversibility », both as concept and as a cinematographic effect; then on thenotion of cinema as an artificial, autonomous and expressive form of thought. By tracing the evolution of the« cinematic speech » in Epstein’s works, several problematics appear to be shared with Merleau-Ponty’sontology of Flesh. The fourth and last part of the thesis presents a series of critical propositions based on the concepts emanating from the moving picture. In the end, this research suggest the possibility to practice a« cinematic » philosophy within the internal crisis of Merleau-Ponty’s conceptual structure.

Le virus d’Epstein-Barr (EBV) est un herpesvirus dont la séroprévalence est d’environ 90 % de la population adulte mondiale. EBV est associé à de nombreuses pathologies tumorales. La primo infection conduit à l’établissement du virus sous forme latente dans les lymphocytes B mémoires. Au sein de ces cellules B, le génome viral est sous la forme d’un épisome, un ADN circulaire double brin, et une fraction restreinte de gènes viraux est exprimée. Afin de se maintenir aux cours des divisions cellulaires, le génome viral est répliqué en phase S par la machinerie cellulaire et ségrégé lors de la mitose dans chaque cellules filles. La réplication et la ségrégation du génome viral nécessitent 2 facteurs viraux que sont la protéine virale EBNA1 (Epstein-Barr Nuclear Antigen 1) et la région oriP sur le génome viral. En phase S, EBNA1 interagit directement avec l’oriP et y recrute le complexe de pré-réplication de l’ADN. En mitose, EBNA1 ancre l’épisome à la chromatine ce qui permet une ségrégation efficace. Les mécanismes d’interaction entre EBNA1 et la chromatine reste encore flou. Au cours de notre travail, nous avons identifié la protéine RCC1 comme un partenaire potentiel pour la protéine EBNA1 pouvant être impliqué dans l’ancrage d’EBNA1 à la chromatine. Nous avons validé cette interaction et caractérisé les régions d’interactions pour ces deux protéines. Par ailleurs nous avons démontré que RCC1 est recrutée sur l’oriP en présence d’EBNA1 et que ces deux protéines interagissent en mitose. À la lumière de nos résultats et des données de la littérature, nous proposons que l’interaction d’EBNA1 avec la chromatine est dynamique et implique à la fois des interactions directes (AT-Hook, interaction avec les nucléosomes) mais aussi des facteurs cellulaires (RCC1, EBP2 et HMGB2). / Epstein-Barr virus (EBV) is a ubiquitous herpesvirus associated with several human cancers. In proliferating latently-infected cells, the EBV genome persists as a circular plasmid that is replicated once per cell cycle and partitioned at mitosis. Both of these processes require a single viral protein, Epstein Barr nuclear antigen 1 (EBNA1), which binds to two clusters of cognate binding sites within the origin of plasmid replication (oriP). EBNA1 plays an essential role both in viral episome replication, by recruiting the cellular complex of DNA replication onto the oriP, and in the efficient segregation of the viral episomes, by tethering the viral DNA onto the mitotic chromosomes. Whereas the mechanisms of viral DNA replication have been well documented, the mechanisms involved in tethering EBNA1 to the cellular chromatin are far from being understood. Here we have identified Regulator of Chromosome Condensation 1 (RCC1) as a novel EBNA1 cellular partner. RCC1 is the only known nuclear guanine nucleotide exchange factor (RanGEF) for the small GTPase Ran enzyme. RCC1, associated with chromatin, is involved in the formation of RanGTP gradients critical for nucleo-cytoplasmic transport, mitotic spindle formation, and nuclear envelope reassembly after mitosis. We have used several approaches to demonstrate a direct interaction between these two proteins and to identify the regions. involved Moreover, by using Chromatin ImmunoPrecipitation assay (ChIP) we have shown that RCC1 is enriched in the oriP region of mini viral replicons in a manner dependent on EBNA1. Finally, by using a combination of confocal microscopy and FRET analysis to follow the dynamics of interaction between the two proteins throughout the cell cycle, we have demonstrated that EBNA1 and RCC1 closely associate on the chromosomes during metaphase. Taken together, our data strongly suggest an essential role for RCC1 in tethering EBNA1 - linked to the viral episome - to the metaphasic chromosomes. Our results and those of others lead us to the idea that the interaction between EBNA1 with the cellular chromosomes requires several factors such as direct interactions or cellular proteins and these interactions are complementary and / or redundant.

Orientadores: Sandra Cecília Botelho Costa, Sandra Helena Alves Bonon / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas / Made available in DSpace on 2018-08-24T11:43:36Z (GMT). No. of bitstreams: 1 Peigo_MurilodeFreitas_M.pdf: 1466925 bytes, checksum: 094e2cd00645843fd5fa2c56ca66c2d5 (MD5) Previous issue date: 2012 / Resumo: O Lúpus Eritematoso Sistêmico (LES) é uma patologia sistêmica do tecido conjuntivo, que se apresenta de maneira variada na dependência do órgão afetado, da gravidade de seu acometimento e da idade do paciente, tendo influência de fatores raciais, de padrões imunológicos e ambientais. Pacientes lúpicos têm grande predisposição para desenvolver infecções graças à imunossupressão induzida pela própria doença como pelo uso de vários medicamentos em seu tratamento. Infecções causadas por herpesvírus, principalmente o Citomegalovírus Humano (CMV) e o Epstein-Barr (EBV), têm sido implicadas em várias doenças autoimunes graves, incluindo o LES. A reativação dos herpesvírus 6 e 7 (HHV-6 e HHV-7) geralmente ocorre em pacientes imunodeprimidos, mas seus papéis ainda são pouco estudados. As infecções por herpesvírus têm influência tanto no início do processo autoimune quanto na exacerbação da progressão da doença. A identificação de pacientes com alto risco de desenvolver doença pelos herpesvírus pode ser realizada utilizando técnicas de detecção de infecção ativa, como a Reação em Cadeia da Polimerase (Nested-PCR) e a detecção do antígeno pp65 do CMV (Antigenemia). Dependendo do caso, estes pacientes podem receber tratamento com antivirais. Diante do exposto, os objetivos deste estudo foram: monitorizar os pacientes com LES em relação à infecção ativa por CMV, EBV, HHV-6 e HHV-7, utilizando as técnicas de Nested-PCR e de antigenemia, bem como avaliar o impacto clínico dessas infecções. Foram incluídos neste trabalho, amostras de sangue de 71 pacientes em seguimento no Departamento de Reumatologia da Faculdade de Ciências Médicas ¿ UNICAMP, com diagnóstico de LES confirmado, sendo que 20/71 (28%) estavam com o lúpus ativo (SLEDAI ? 8) e 51/71 (72%) dos pacientes não tinham atividade lúpica (SLEDAI < 8). Das amostras de sangue pesquisadas, 10/71 (14%) foram positivas para os herpesvírus estudados, sendo que 90% destes pacientes com infecção ativa apresentavam o lúpus em atividade (p?0,006). Infecção ativa pelo CMV ocorreu em 4 pacientes (5,6%). HHV-7 foi detectado em 4 amostras (5,6%). Dois outros pacientes apresentaram dupla infecção por CMV e HHV-7 (2,8%). Infecção ativa pelo EBV e HHV-6 não foi detectada em nenhuma das amostras analisadas. Dois pacientes foram a óbito, sendo que um deles evoluiu com sepse de foco pulmonar (provável doença por CMV) e o outro com sepse por Psedomonas aeruginosa. Diante dos resultados obtidos, podemos observar que a infecção ativa pode ocorrer nos pacientes com LES, principalmente naqueles com a doença em atividade. Poucos estudos têm avaliado o impacto destas infecções no cuidado diário dos pacientes com LES. Acreditamos que este trabalho seja pioneiro e será de fundamental importância, contribuindo com este grupo de pacientes. Entretanto, futuros estudos deverão ser implementados com um número maior de pacientes e de coletas/paciente, principalmente naqueles com LES em atividade, que foram demonstrados com aqueles com fator de risco aumentado / Abstract: Systemic lupus erythematosus (SLE) is a connective tissue systemic pathology that presents itself in several ways, depending on the organ affected, the seriousness of the disease and patient¿s age, being influenced by racial factors, immunologic and environmental patterns. SLE patients have great predisposition to develop infections due to the immunosuppression induced by the disease itself and by the use of medicine in the treatment. Infections caused by herpesvirus, especially Human Cytomegalovirus (CMV) and Epstein-Barr (EBV), have been developed into several serious autoimmune diseases, including SLE. Herpesvirus 6 and 7 (HHV-6 and HHV-7) reactivation generally occurs in immunodepressed patients, but their roles are unclear. Herpesvirus infections have influence both on the beginning of the autoimmune process and on the aggravation of the disease progression. The patients that present high risks of developing herpesvirus related diseases can be identified using active infection detection techniques, such as the Nested polymerase chain reaction (Nested-PCR) and the CMV pp65 antigen detection (antigenemia). Depending on the case, the patients can receive treatment with antivirals. Face to the exposed, the objectives of this study were: to monitor the patients with SLE with regard to active infection by CMV using Nested-PCR and antigenemia techniques, and EBV, HHV-6, HHV-7 in serum, as well as to evaluate the clinic impact to these infections. There were included in this work blood samples of 71 patients that are being treated at the Department of Rheumatology, Faculty of Medical Sciences ¿ University of Campinas - UNICAMP, with a confirmed SLE diagnosis, given that 20/71 (28%) had active lupus (SLEDAI ? 8) and 51/71 (72%) of the patients didn¿t present lupic activity (SLEDAI < 8). Considering the blood samples researched, 10/71 (14%) were positive for the studied herpesvirus, and 90% of the patients with active infection presented lupus in activity (p ? 0,006). Active infection by CMV was observed in 4 patients (5,6%). HHV-7 was detected in 4 samples (5,6%). Two other patients presented double infection by CMV and HHV-7 (2,8%). Active infection by EBV and HHV-6 was not detected in any of the analyzed samples. Two patients have deceased, whose conditions developed into pulmonary sepsis (probable disease by CMV) and into Psedomonas aeruginosa sepsis, respectively. After analyzing the achieved results, we observe that active infection can appear in patients with SLE, especially in those with the disease in activity. Few studies have evaluated the impact of these infections on the daily care of patients with SLE. In this sense, we believe that this work is pioneer and that it will be of fundamental importance, contributing to this group of patients. However, future studies should be implemented, with a larger number of patients and samples, especially those with SLE in activity, which are the ones with increased risk factor as shown / Mestrado / Clinica Medica / Mestre em Clinica Medica

Multiple sclerosis is a complex immune mediated condition of the central nervous system characterized by myelin loss and progressive neurodegeneration. The risk of developing MS is influenced by both genetic and environmental agents and, among them, several lines of evidence support a role for vitamin D deficiency, Epstein-Barr virus (EBV) infection and smoking in the aetiology of this disease. The aim of this work was to further elucidate how nature and nurture act in the causal cascade leading to MS. In chapter 1, I show that the main genetic factor in adult MS (the HLA-DRB1*1501 allele) plays an equally important role in paediatric cases of MS (PMS) and that EBV negative PMS patients represent a separate entity characterized by lower age at disease onset, lower female to male ratio and a trend towards a lower frequency of the HLA-DRB1*1501 allele. In chapter 2, I provide evidence in support of month of birth having a role on MS risk and T cell production and that vitamin D may underlie this effect. In chapter 3 I demonstrate the presence of a link between vitamin D deficiency and the immune response against EBV, whereby the proportion of EBV seropositive MS patients and controls increases with increasing latitude and high dose vitamin D supplementation appears to reduce the level of antibodies against this virus. In chapter 4, I show that MS associated genetic variants are located in genomic regions that exert a regulatory function and are active in immune cell types. In chapter 5, I illustrate how vitamin D receptor binding is also located within active regulatory regions in immune cells and that this is particularly evident near MS associated genes. Finally, in chapter 6, I use chromatin data on more than 100 different cell types and conclude that MS associated genetic variants are particularly active in T helper, T cytotoxic and B cells. Further work is needed to elucidate how genetic and environmental agents play a role in the cause of MS and to develop effective strategies for disease treatment and prevention.