La broncho-pneumopathie chronique obstructive (BPCO) est une maladie inflammatoire chronique des voies aériennes dont le facteur de risque principal est l’exposition chronique à la fumée de cigarette. L’histoire de la maladie est fréquemment associée à une colonisation bactérienne des voies aériennes et ponctuée d’épisodes aigus d’exacerbation de la maladie associés à une morbi-mortalité importante. Ces exacerbations sont principalement d’origine infectieuses et plus particulièrement, associées à une bactérie dans 50 % des cas, majoritairement Haemophilus influenzae, Streptococcus pneumoniae et Moraxella catarrhalis. Le contrôle de ces infections bactériennes implique en particulier une réponse immunitaire de type Th17 efficace. Cette immunité Th17 médiée principalement par les cytokines IL-17A et IL-22 est impliquée dans la physiopathologie de la BPCO mais n’a été que peu étudiée dans le contexte des exacerbations. Notre hypothèse est que la réponse Th17 aux pathogènes est altérée dans la BPCO, mécanisme qui serait impliqué dans la susceptibilité aux infections respiratoires observée chez les patients.Différentes approches ont été utilisées pour tester cette hypothèse. Tout d’abord, une approche ex vivo, à partir de cellules mononucléées circulantes (PBMC) de patients atteints de BPCO comparées à celles issues de sujets sains non fumeurs et de sujets fumeurs sans obstruction bronchique, montrant un défaut de production par les PBMC des cytokines IL-17A et IL-22 mais également des cytokines IL-6 et IL-23 produites par les cellules présentatrices d’antigènes (CPA) et impliquées dans l’activation de cette immunité Th17, en réponse à une activation par S. pneumoniae. Ensuite, une approche in vitro, avec un modèle de cellules dendritiques dérivées de monocytes (MDDC) exposées à la fumée de cigarette. Ces MDDC présentaient un défaut de maturation, de production de cytokines pro-Th17 et de leur capacité à activer une réponse Th17 lymphocytaire en réponse à S. pneumoniae. Enfin, une approche in vivo, utilisant un modèle murin de souris exposées de façon chronique à la fumée de cigarette confirmant ces résultats avec un défaut de réponse IL-17A et IL-22 mais également de production des cytokines pro-Th17 IL-1β et IL-23 par les CPA en réponse à S. pneumoniae. Dans ce modèle, l’apport d’IL-22 permettait d’améliorer la clairance bactérienne et de réduire les lésions pulmonaires, suggérant des possibilités thérapeutiques pour améliorer la prise en charge de ces exacerbations infectieuses.Ces trois approches permettent d’apporter des arguments forts en faveur d’un défaut de réponse Th17 au cours des exacerbations bactériennes de la BPCO, hypothèse confortée par d’autres travaux de notre équipe montrant dans le modèle murin d’exposition chronique à la fumée de cigarette la présence d’un défaut de production d’IL-22 dans la réponse à Haemophilus influenzae. Ces travaux qui doivent maintenant être d’une part, confirmés par une étude clinique incluant des patients atteints de BPCO en exacerbation, et d’autre part, complétés pour préciser l’impact sur les cellules lymphoïdes innées productrices de ces cytokines et sur la réponse de l’épithélium bronchique à l’infection, ouvrent la voies à des perspectives thérapeutiques dans la prise en charge de ces exacerbations bactériennes. / Chronic obstructive pulmonary disease (COPD) is a chronic inflammatory disease of the airways mainly due to chronic exposure to cigarette smoke. Evolution of the disease is often associated with bacterial colonization of the airways and punctuated by acute exacerbation of the disease with a frequent related morbi-mortality. These exacerbations are mainly due to infection and almost 50 % are associated with bacteria, often Haemophilus influenzae, Streptococcus pneumoniae and Moraxella catarrhalis. Th17 immune response is particularly involved in control of bacterial infection and is principally mediated by IL-17A and IL-22 cytokines. This Th17 inflammation is involved in COPD physiopathology but there is paucity of data focusing on this immune response during COPD exacerbations. Our hypothesis is that Th17 immune response to pathogens is defective in COPD leading to airways infection susceptibility.We have tested our hypothesis by different approaches. First, the ex vivo responses to Streptococcus pneumoniae of peripheral blood mononuclear cells (PBMC) from COPD patients, healthy non smokers and healthy smokers were compared showing decreased production of IL-17A and IL-22 but also of pro-Th17 cytokines IL-6 and IL-23 which are produced by antigen presenting cells (APC). Second, we used an in vitro model of monocyte-derived dendritic cells (MDDC) exposed to cigarette smoke showing a defective MDDC maturation, pro-Th17 cytokines production and ability to promote T-cells Th17 response, in response to S. pneumoniae. Finally, an in vivo murine model of mice chronically exposed to cigarette smoke showing defective production of IL-17A and IL-22 but also of pro-Th17 cytokines IL-1β and IL-23 produced by APC, in response to S. pneumoniae. In this model, supplementation with IL-22 restored bacterial clearance and limited lung alterations suggesting therapeutic opportunities to improve infectious COPD exacerbation management.Altogether, these results strengthen our hypothesis of a defective Th17 immune response during bacterial COPD exacerbations. They are comforted by other studies in our team showing a defective IL-22 production in response to Haemophilus influenzae in our in vivo model of mice chronically exposed to cigarette smoke. Now we have to confirm these results in a clinical trial including COPD patients in exacerbation and to further explore the impact on innate lymphoid cells, which produced these cytokines, and on the innate immune response of epithelial cells to infection, in order to develop new infectious COPD exacerbation therapeutics.

A Análise de Acoplamentos Estatísticos é uma técnica computacional capaz de identificar resíduos importantes para a estrutura e função de proteínas em uma família por meio da quantificação de conservação posicional, correlação entre posições e identificação de grupos de resíduos correlacionados entre si. Neste trabalho, a análise de acoplamentos estatísticos foi implementada e aplicada ao estudo das proteínas tirosina fosfatases. Em conjunto com as proteínas tirosina quinases (PTKs), que adicionam um grupo fosforil a um resíduo de tirosina em uma proteína, as proteínas tirosina fosfatases (PTPs), que o removem, são responsáveis por diversos processos de sinalização celular. Elas são um caso de evolução convergente, onde um subgrupo (as proteínas tirosina fosfatases de baixo peso molecular) não apresenta homologia às chamadas PTPs \"clássicas\", capazes de defosforilar apenas resíduos de tirosina, e às fosfatases de especifidicade dupla, capazes de defosforilar também resíduos de serina e treonina, além de substratos não-protéicos. Em comum, as três subfamílias apresentam apenas o motivo CX5R, característico para todas as PTPs. Através do estudo das três subfamílias utilizando a análise de acoplamentos estatísticos, foi possível obter uma descrição detalhada de suas características conservadas e correlacionadas, relacionando-as ao conhecimento acumulado sobre proteínas tirosina fosfatases e a questões em aberto como a regulação por dimerização, a especificidade e mutações relacionadas a patologias. Foi possível também apresentar um método capaz de distinguir proteínas tirosina fosfatases de baixo peso molecular das arsenato redutases, derivadas das primeiras por evolução divergente. Adicionalmente, a técnica foi aplicada ao estudo das hexoquinases, às superóxido dismutases e às peroxidases. A tese descreve também estudos desenvolvidos pelo autor na área de cristalografia de proteínas a determinação das estruturas da Transtirretina humana em complexo com genisteína, da holo-Hexoquinase PI de S. cerevisae, do complexo IL-22/IL-22R1 e da Laminarinase de R. marinus. / The statistical coupling analysis is a computational technique which can identify important residues for the structure and function of proteins in a family by quantifying positional conservation, correlation between positions and identifying groups of self-correlating residues. Its implementation in this research group was applied to the study of the protein tyrosine phosphatases. Together with the protein tyrosine kinases (PTKs), which add a phosphoryl group to a tyrosine residue in proteins, the protein tyrosine phosphatases (PTPs), which remove it, are responsible for a variety of cell signaling processes. They are a case of convergent evolution, since one subgroup (the low molecular weight protein tyrosine phosphatases) are not homologous to the classical phosphatases, which can only dephosphorilate tyrosine residues, and the dual-specificity phosphatases, which can also dephosphorilate serine and threonine residues, and also non-proteinaceous substrates. All three sub-families have, in common, the CX5R motif, a characteristic of all PTPs. By applying the statistical coupling analysis to the study of the three sub-families, it was possible to obtain a detailed depiction of their conserved and correlated characteristics, relating them to the accumulated knowledge on protein tyrosine phosphatases and open questions such as protein regulation by dimerization, specificity and disease-related mutations. It was also possible to present a method to distinguish between low molecular weight phosphatases and arsenate reductases, which are derived by the former by divergent evolution. In addition, the technique was applied to the study of hexokinases, superoxide dismutases and peroxidases. The thesis also describe studies developed by the author in the field of protein crystallography the structure determination of human transthyretin in complex with genistein, holo-hexokinase PI from S. cerevisae, the IL-22/IL-22R1 complex and the laminarinase from R. marinus.

Cardiac transplantation is governed by complex immunological mechanisms contributing to different types of allograft rejection. Early non-specific graft failure and chronic rejection (cardiac allograft vasculopathy) represent the main limitations for the recipients’ short- and long-term survival respectively. To date, the pathogenesis of both rejection types remains ill-defined. However, it is believed that they are related to an immunologically mediated potent inflammatory process, occurring whether early after transplantation (acute), or lasting for the lifetime of the graft (chronic).<p> <p>The initiating mechanisms of chronic rejection in solid organ transplantation remain ill-defined. Emerging evidence sustains that graft vasculopathy is primarily driven by alloreactive CD4+ T lymphocytes sensitized by the indirect pathway of allorecognition. To date, whereas the nature of APCs involved in this particular pathway has yet to be identified, it appears challenging to speculate that recipient-derived endothelial cells (ECs) repopulating the graft may represent the main cell targets recognized by indirectly primed alloreactive CD4+ T cells to mediate the rejection of cardiac transplants. In the first part of this thesis, we specifically studied the indirect pathway of allorecognition with a transgenic mice (Marilyn mice) model that expresses a T cell receptor (TCR) transgene which recognizes the male antigen H-Y in an I-Ab-restricted fashion. Our results provide evidence that graft endothelium replacement by recipient-type cells expressing MHC Class II molecules is required for the chronic rejection of vascularized cardiac transplants mediated by indirect pathway alloreactive CD4+ T cells.<p><p>The purpose of the second part of the thesis was to investigate the potential implication of interleukin-22 (IL-22), an early phase secreted proinflammatory cytokine of the IL-10 family, in the acute rejection of cardiac allografts. IL-22 was recently described as an effector key modulator of the inflammatory process produced mainly by differentiated CD4+ T cells of the Th17 lineage. As being closely related to IL-10 and IL-17, both involved in the rejection process of vascularized heart allografts, we attempted to determine the precise role of IL-22 in this process. Experiments were conducted with a recently developed murine model deficient for the IL-22 gene (IL-22KO). The results of the second part of the thesis show that IL-22 is not an effector cytokine in cardiac allograft rejection. In contrast, as being early expressed into the allograft, likely IL-22 plays a protective role in the inflammation leading to acute cardiac rejection, probably depending on a neutrophil-related mechanism. <p><p><p>In conjunction with current understanding of inflammatory and antigen-specific events in allografts, overall, our results provide new insights into the mechanisms of chronic and acute cardiac rejection, thus prompting to further interrogations and appealing novel therapeutic strategies. Pharmacologic manipulation of endothelium is challenging. Given their capacity to sense and rapidly respond to the local environment, ECs are the ideal targets for rapid systemic delivery of therapeutic agents. Combination therapy is required to reduce inflammatory reaction and endothelial activation, to modulate endothelial dysfunction and promote endothelial survival. Also, given that IL-22 may alleviate tissue destruction during inflammatory responses, therapies that enhance its production and protective action in the transplanted organs seem attractive to specifically affect tissue responses, without exerting direct effects on the immune response.<p><p><p> / Doctorat en Sciences médicales / info:eu-repo/semantics/nonPublished

Introdução: A rinite alérgica (RA) e a rinossinusite crônica (RSC) são doenças inflamatórias nasais com prevalência alta e crescente. Estima-se que 15,5% dos norte-americanos tenham RSC, e estudo recente encontrou prevalência de 5,51% na cidade de São Paulo, enquanto a RA acomete entre 10 e 20% da população mundial. Apesar de terem mecanismos fisiopatológicos distintos, em ambas, há recrutamento de células de defesa, principalmente linfócitos T, e produção de citocinas inflamatórias. Esses mediadores variam não apenas entre as doenças, mas também entre as populações acometidas, e seu conhecimento é importante para o diagnóstico correto e direcionamento da terapia escolhida. Objetivos: Mapear os mediadores inflamatórios presentes no lavado nasal e no condensado do ar exalado na RSC e na RA, avaliando possíveis biomarcadores da doença, e analisar o endotipo inflamatório dos pacientes estudados. Além disso, avaliar a qualidade de vida, o nível de obstrução nasal, a qualidade do sono dos pacientes afetados, o transporte mucociliar e coletar material para análise de pH, contagem de células totais e seu diferencial. Pacientes e métodos: Estudo exploratório prospectivo em corte transversal, sendo os pacientes divididos em quatro grupos: 1) Grupocontrole com pacientes sem queixas; 2) Pacientes com RA com prick test positivo; 3) Pacientes com RSC com polipose; e 4) Pacientes com RSC sem polipose. Todos os pacientes responderam a quatro questionários: 20-Item Sino-Nasal Outcome Test (SNOT-20p), Nasal Obstruction Symptom Evaluation (NOSE), o Índice de Qualidade do Sono de Pittsburgh (Pittsburgh Sleep Quality Index - PSQI-BR) e o questionário para triagem e diagnóstico da asma da European Community Respiratory Health Survey (ECRHS). Foi realizado exame físico, incluindo endoscopia nasal (escore de Lund- Kennedy modificado) e, nos pacientes com RSC, avaliação da tomografia computadorizada (TC) de face (escore de Lund-Mackay). Foi também avaliado o transporte mucociliar por meio do teste da sacarina. Coletou-se o condensado do ar exalado para análise do pH e lavado nasal para avaliação do pH, da presença de citocinas e da celularidade (total e diferencial). Foi avaliada a presença de IL-4, IL-5, IL-8, IL-17A, IL-22, TNF-Alfa e IFN-Gama no lavado nasal e IL-5, IL-17A, IL-22 e IFN-Gama no condensado do ar exalado. Resultados: Os pacientes com RSC apresentaram escores significativamente piores nos questionários de obstrução nasal (NOSE, p < 0,01) e qualidade de vida (SNOT-20p, p < 0,01) quando comparados aos controles, e tanto os pacientes com RSC quanto com RA apresentaram pior qualidade do sono (PSQI-BR, p < 0,01). O escore de extensão de Lund- Mackay foi mais elevado nos pacientes com RSC com polipose (p < 0,02). O teste da sacarina apresentou tempo mais prolongado no grupo RSC com polipose (p < 0,01). O pH do condensado do ar exalado não diferiu entre os grupos. O grupo RSC com polipose apresentou tanto diferença do pH (p < 0,01) quanto da contagem de células totais do lavado nasal (p < 0,01) quando comparado ao grupo-controle, porém sem diferença na contagem diferencial. IFN? do condensado foi mais elevado no grupo RA em comparação ao grupo C (p=0,05), enquanto IL-5 foi mais alto no grupo RSC com polipose quando comparado ao grupo RSC sem polipose (p=0,02). Os pacientes foram, então, divididos em endotipos, segundo os grupos descritos por Tomassen et al., sendo que endotipos são os subtipos da doença definidos funcionalmente e patologicamente por mecanismos moleculares distintos. Conclusão: Pacientes com RSC apresentaram escores piores nos questionários de qualidade de vida (SNOT-20p e NOSE), o que, em parte, poderia ser atribuído à pior qualidade do sono apresentada tanto por estes pacientes quanto pelos portadores de RA. O teste da sacarina evidenciou pior transporte mucociliar nos pacientes com RSC com polipose. Não houve diferença do pH do condensado do ar exalado, sugerindo que, apesar de interessante na avaliação das vias aéreas inferiores, este pode não ser um bom teste para análise das vias aéreas superiores. Foram encontradas alterações significantes tanto do pH quanto da contagem de células totais do lavado nasal do grupo com RSC com polipose, sem, no entanto, haver diferença na contagem diferencial. Dos 17 pacientes com RSC com perfil completo de citocinas, 12 se encaixam em endotipos já descritos, sendo que, dos cinco restantes, dois apresentam o mesmo perfil, podendo indicar um novo subgrupo / Introduction: Allergic rhinitis (AR) and chronic rhinosinusitis (CRS) are nasal inflammatory diseases with high and increasing prevalence. It is estimated that 15.5% of Americans have CRS, and a recent study found a prevalence of 5.51% in the city of São Paulo, while AR affects between 10 and 20% of the world population. Although they have distinct pathophysiological mechanisms, in both there is recruitment of defense cells, mainly T lymphocytes, and production of inflammatory cytokines. These mediators vary not only between diseases but also among affected populations, and their knowledge is important for the correct diagnosis and targeting of the therapy chosen. Objectives: To map the inflammatory mediators present in the nasal wash and the exhaled breath condensate in the CRS and AR, evaluating possible biomarkers of this diseases, and to analyze the inflammatory endotype of the patients studied. In addition, assess quality of life, level of nasal obstruction, sleep quality of affected patients, mucociliary transport and collect samples for pH analysis, total cell count and its differential. Patients and Methods: Prospective cross-sectional exploratory study, divided into four groups: 1) Control group with patients without complaints 2) Patients with AR with prick test positive 3) Patients with CRS with polyps 4) Patients with CRS without polyps. All patients responded to four questionnaires: 20-Item Sino-Nasal Outcome Test (SNOT-20p), Nasal Obstruction Symptom Evaluation (NOSE), Pittsburgh Sleep Quality Index (PSQI-BR) and European Community Respiratory Health Survey (ECRHS) questionnaire for screening and diagnosis of asthma. A physical examination was performed, including nasal endoscopy (modified Lund-Kennedy score) and, in patients with CRS, a computerized tomography (Lund-Mackay score) evaluation. The mucociliary transport was also evaluated through the saccharin test. The exhaled breath condensate was collected for pH analysis and the nasal wash for evaluation of pH, cytokines and cellularity (total and differential). The presence of IL-4, IL-5, IL-17, IL-17A, IL-22, TNF-Alfa and IFN-Gama in the nasal wash and IL-5, IL-17A, IL-22 and IFN-Gama in the exhaled breath condensate. Results: Patients with CRS had significantly worse scores in the nasal obstruction questionnaire (NOSE, p < 0.01) and quality of life questionnaire (SNOT-20p, p < 0.01) when compared to controls, and both patients with CRS and AR presented worse sleep quality (PSQI-BR, p < 0.01). The Lund-Mackay extension score was higher in patients with CRS with polyps (p < 0.02). The saccharin test showed longer time in the CSR group with polyps (p < 0.01). The pH of the exhaled breath condensate did not differ between groups. The CRS with polyps group presented both pH difference (p < 0.01) and higher total nasal wash cell count (p < 0.01) when compared to the control group, but with no difference in the differential count (p = 0.05), while IL-5 was higher in the CRS group with polyps when compared to the RSC without polyps group (p = 0.02). Patients were then divided into endotypes according to the groups described by Tomassen et al, Endotypes are the subtypes of the disease defined functionally and pathologically by distinct molecular mechanisms. Conclusions: Patients with CRS presented worse scores on quality of life questionnaires (SNOT-20p and NOSE), which could be attributed in part to the poorer quality of sleep presented by both patients with CRS and AR. The saccharin test evidenced worse mucociliary transport in patients with CRS with polyps when compared with control group. There was no difference in the pH of the exhaled breath condensate, suggesting that, although interesting in the evaluation of the lower airways, this may not be a good test for analyzing the upper airways. Significant alterations were found in both pH and total nasal wash cell count in the CSR group with polyposis, but there was no difference in the differential count. Of the 17 patients with CRS with complete cytokine profile, 12 fit into already described endotypes, and of the remaining five, two have the same profile, which may indicate a new subgroup

Introdução: A rinite alérgica (RA) e a rinossinusite crônica (RSC) são doenças inflamatórias nasais com prevalência alta e crescente. Estima-se que 15,5% dos norte-americanos tenham RSC, e estudo recente encontrou prevalência de 5,51% na cidade de São Paulo, enquanto a RA acomete entre 10 e 20% da população mundial. Apesar de terem mecanismos fisiopatológicos distintos, em ambas, há recrutamento de células de defesa, principalmente linfócitos T, e produção de citocinas inflamatórias. Esses mediadores variam não apenas entre as doenças, mas também entre as populações acometidas, e seu conhecimento é importante para o diagnóstico correto e direcionamento da terapia escolhida. Objetivos: Mapear os mediadores inflamatórios presentes no lavado nasal e no condensado do ar exalado na RSC e na RA, avaliando possíveis biomarcadores da doença, e analisar o endotipo inflamatório dos pacientes estudados. Além disso, avaliar a qualidade de vida, o nível de obstrução nasal, a qualidade do sono dos pacientes afetados, o transporte mucociliar e coletar material para análise de pH, contagem de células totais e seu diferencial. Pacientes e métodos: Estudo exploratório prospectivo em corte transversal, sendo os pacientes divididos em quatro grupos: 1) Grupocontrole com pacientes sem queixas; 2) Pacientes com RA com prick test positivo; 3) Pacientes com RSC com polipose; e 4) Pacientes com RSC sem polipose. Todos os pacientes responderam a quatro questionários: 20-Item Sino-Nasal Outcome Test (SNOT-20p), Nasal Obstruction Symptom Evaluation (NOSE), o Índice de Qualidade do Sono de Pittsburgh (Pittsburgh Sleep Quality Index - PSQI-BR) e o questionário para triagem e diagnóstico da asma da European Community Respiratory Health Survey (ECRHS). Foi realizado exame físico, incluindo endoscopia nasal (escore de Lund- Kennedy modificado) e, nos pacientes com RSC, avaliação da tomografia computadorizada (TC) de face (escore de Lund-Mackay). Foi também avaliado o transporte mucociliar por meio do teste da sacarina. Coletou-se o condensado do ar exalado para análise do pH e lavado nasal para avaliação do pH, da presença de citocinas e da celularidade (total e diferencial). Foi avaliada a presença de IL-4, IL-5, IL-8, IL-17A, IL-22, TNF-Alfa e IFN-Gama no lavado nasal e IL-5, IL-17A, IL-22 e IFN-Gama no condensado do ar exalado. Resultados: Os pacientes com RSC apresentaram escores significativamente piores nos questionários de obstrução nasal (NOSE, p < 0,01) e qualidade de vida (SNOT-20p, p < 0,01) quando comparados aos controles, e tanto os pacientes com RSC quanto com RA apresentaram pior qualidade do sono (PSQI-BR, p < 0,01). O escore de extensão de Lund- Mackay foi mais elevado nos pacientes com RSC com polipose (p < 0,02). O teste da sacarina apresentou tempo mais prolongado no grupo RSC com polipose (p < 0,01). O pH do condensado do ar exalado não diferiu entre os grupos. O grupo RSC com polipose apresentou tanto diferença do pH (p < 0,01) quanto da contagem de células totais do lavado nasal (p < 0,01) quando comparado ao grupo-controle, porém sem diferença na contagem diferencial. IFN? do condensado foi mais elevado no grupo RA em comparação ao grupo C (p=0,05), enquanto IL-5 foi mais alto no grupo RSC com polipose quando comparado ao grupo RSC sem polipose (p=0,02). Os pacientes foram, então, divididos em endotipos, segundo os grupos descritos por Tomassen et al., sendo que endotipos são os subtipos da doença definidos funcionalmente e patologicamente por mecanismos moleculares distintos. Conclusão: Pacientes com RSC apresentaram escores piores nos questionários de qualidade de vida (SNOT-20p e NOSE), o que, em parte, poderia ser atribuído à pior qualidade do sono apresentada tanto por estes pacientes quanto pelos portadores de RA. O teste da sacarina evidenciou pior transporte mucociliar nos pacientes com RSC com polipose. Não houve diferença do pH do condensado do ar exalado, sugerindo que, apesar de interessante na avaliação das vias aéreas inferiores, este pode não ser um bom teste para análise das vias aéreas superiores. Foram encontradas alterações significantes tanto do pH quanto da contagem de células totais do lavado nasal do grupo com RSC com polipose, sem, no entanto, haver diferença na contagem diferencial. Dos 17 pacientes com RSC com perfil completo de citocinas, 12 se encaixam em endotipos já descritos, sendo que, dos cinco restantes, dois apresentam o mesmo perfil, podendo indicar um novo subgrupo / Introduction: Allergic rhinitis (AR) and chronic rhinosinusitis (CRS) are nasal inflammatory diseases with high and increasing prevalence. It is estimated that 15.5% of Americans have CRS, and a recent study found a prevalence of 5.51% in the city of São Paulo, while AR affects between 10 and 20% of the world population. Although they have distinct pathophysiological mechanisms, in both there is recruitment of defense cells, mainly T lymphocytes, and production of inflammatory cytokines. These mediators vary not only between diseases but also among affected populations, and their knowledge is important for the correct diagnosis and targeting of the therapy chosen. Objectives: To map the inflammatory mediators present in the nasal wash and the exhaled breath condensate in the CRS and AR, evaluating possible biomarkers of this diseases, and to analyze the inflammatory endotype of the patients studied. In addition, assess quality of life, level of nasal obstruction, sleep quality of affected patients, mucociliary transport and collect samples for pH analysis, total cell count and its differential. Patients and Methods: Prospective cross-sectional exploratory study, divided into four groups: 1) Control group with patients without complaints 2) Patients with AR with prick test positive 3) Patients with CRS with polyps 4) Patients with CRS without polyps. All patients responded to four questionnaires: 20-Item Sino-Nasal Outcome Test (SNOT-20p), Nasal Obstruction Symptom Evaluation (NOSE), Pittsburgh Sleep Quality Index (PSQI-BR) and European Community Respiratory Health Survey (ECRHS) questionnaire for screening and diagnosis of asthma. A physical examination was performed, including nasal endoscopy (modified Lund-Kennedy score) and, in patients with CRS, a computerized tomography (Lund-Mackay score) evaluation. The mucociliary transport was also evaluated through the saccharin test. The exhaled breath condensate was collected for pH analysis and the nasal wash for evaluation of pH, cytokines and cellularity (total and differential). The presence of IL-4, IL-5, IL-17, IL-17A, IL-22, TNF-Alfa and IFN-Gama in the nasal wash and IL-5, IL-17A, IL-22 and IFN-Gama in the exhaled breath condensate. Results: Patients with CRS had significantly worse scores in the nasal obstruction questionnaire (NOSE, p < 0.01) and quality of life questionnaire (SNOT-20p, p < 0.01) when compared to controls, and both patients with CRS and AR presented worse sleep quality (PSQI-BR, p < 0.01). The Lund-Mackay extension score was higher in patients with CRS with polyps (p < 0.02). The saccharin test showed longer time in the CSR group with polyps (p < 0.01). The pH of the exhaled breath condensate did not differ between groups. The CRS with polyps group presented both pH difference (p < 0.01) and higher total nasal wash cell count (p < 0.01) when compared to the control group, but with no difference in the differential count (p = 0.05), while IL-5 was higher in the CRS group with polyps when compared to the RSC without polyps group (p = 0.02). Patients were then divided into endotypes according to the groups described by Tomassen et al, Endotypes are the subtypes of the disease defined functionally and pathologically by distinct molecular mechanisms. Conclusions: Patients with CRS presented worse scores on quality of life questionnaires (SNOT-20p and NOSE), which could be attributed in part to the poorer quality of sleep presented by both patients with CRS and AR. The saccharin test evidenced worse mucociliary transport in patients with CRS with polyps when compared with control group. There was no difference in the pH of the exhaled breath condensate, suggesting that, although interesting in the evaluation of the lower airways, this may not be a good test for analyzing the upper airways. Significant alterations were found in both pH and total nasal wash cell count in the CSR group with polyposis, but there was no difference in the differential count. Of the 17 patients with CRS with complete cytokine profile, 12 fit into already described endotypes, and of the remaining five, two have the same profile, which may indicate a new subgroup

La barrière hémo-encéphalique (BHE) est formée des cellules endothéliales microvasculaires cérébrales reliées entre elles par des jonctions serrées. Grâce à sa perméabilité restreinte et sélective, la BHE entrave le passage des molécules et cellules du sang vers le système nerveux central (SNC). Chez les patients atteints de sclérose en plaques (SEP), une maladie inflammatoire du SNC, la rupture de la BHE permet aux cellules immunes actives d'infiltrer le tissu cérébral. Il s'ensuit une réaction inflammatoire excessive au cours de laquelle d'autres leucocytes sont recrutés dans le cerveau et qui culmine par la formation des plaques de démyélinisation caractéristiques de la SEP. On dénote au niveau de ces lésions une présence importante de lymphocytes T CD4⁺ activés et de cytokines pro-inflammatoires propres à une réponse de type TH1, tels l’IFN-γ et l’IL-1. Curieusement cependant, l’inhibition de la voie TH1 n’empêche pas l’apparition de la maladie dans le modèle murin de la SEP et en aggrave même les symptômes. On attribue maintenant aux lymphocytes TH17, nommées en raison de leur capacité à produire de l’IL-17, un rôle clé dans le développement de la maladie. L’objectif de ce travail de thèse visait à caractériser les lymphocytes TH17 chez l’humain et définir leur contribution exacte dans la fragilisation de la BHE, une étape décisive dans la formation des lésions de SEP. Pour ce faire, nous avons mis au point une méthode expérimentale permettant l’expansion in vitro de populations de lymphocytes TH17 à partir de cellules mononuclées du sang de donneurs sains. Nos travaux démontrent que l’IL-23 induit la production d’IL-17, d’IL-22 et de granzyme B par les lymphocytes T CD4⁺CD45RO⁺ mémoires humains et qu’une proportion des cellules exprime de manière concomitante de l’IL-17 et de l’IFN-γ. La fréquence des lymphocytes T CD4⁺ IL17⁺, IL-22⁺ et des doubles positifs IL-17⁺IFN-γ⁺ est significativement plus élevée dans les lignées de lymphocytes TH17 provenant de patientes en poussée que dans celles de contrôles. Nos analyses démontrent que les cellules endothéliales de la BHE expriment de faibles niveaux des récepteurs de l’IL-17 et de l’IL-22 à l’état basal mais que leur présence est accrue dans le cerveau de patients atteints de SEP. L’activation du récepteur de l’IL-17 entraîne une augmentation de la perméabilité de la BHE et une perturbation de l’organisation des protéines de jonction occludine et ZO-1. Finalement, nous démontrons que la migration des lymphocytes TH17 à travers la BHE est régie en grande partie par la molécule d’adhérence ICAM-1 et que les lymphocytes qui co-expriment l’IL-17 et l’IFN-γ sont plus aptes à franchir la BHE que ceux qui produisent uniquement l’une ou l’autre de ces cytokines. Nous retrouvons d’ailleurs des cellules qui expriment simultanément les facteurs de transcription T-bet et RORC, associés respectivement aux lymphocytes TH1 et aux TH17, au sein des infiltrats péri-vasculaires des lésions actives de SEP. Les travaux présentés dans cette thèse auront permis d’affiner nos connaissances sur les mécanismes d’entrée des lymphocytes TH17 dans le SNC et les propriétés délétères des cytokines qu’ils sécrètent, notamment dans l’activation et la déstabilisation de l’endothélium cérébral. / The blood-brain barrier (BBB) plays a crucial role in protecting the central nervous system (CNS) by restricting entry of cells and molecules into the brain. In the CNS disorder multiple sclerosis (MS), breakdown of the BBB allows activated leukocytes to infiltrate the brain parenchyma, leading to the formation of the characteristic demyelinated lesions. For decades, MS was viewed as a TH1-mediated disease, a notion that was largely supported by studies in its animal model and by the abundance of prototypical TH1-associated cytokines within active MS lesions. However, over the years, accumulating evidence has highlighted the involvement of another subset of CD4⁺ T cells that express IL-17, therefore named TH17 lymphocytes, in the pathology of the disease. The goal of the work presented herein was to characterize the human TH17 lymphocyte population and define their contribution to the disruption of the BBB and leukocyte infiltration into the CNS, both important early events in the formation of MS lesions. To do so, we developed and optimized a method to successfully generate human TH17 lines in vitro from peripheral blood mononuclear cells of healthy donors. We demonstrate that in response to IL-23, human memory CD4⁺CD45RO⁺ but not naïve CD4⁺CD45RA⁺ T lymphocytes produce IL-17, IL-22, and granzyme B, with a subset of cells simultaneously expressing IL-17 and IFN-γ. Interestingly, we measure a significant increase in the percentage of T CD4⁺ IL17⁺, of IL-22⁺, and of IL-17⁺IFN-γ⁺ dual producers in TH17 cell lines expanded from the peripheral blood of acutely relapsing MS women as compared to those generated from healthy controls and remitting MS patients. We show that both IL-17 and IL-22 receptors are upregulated on BBB endothelial cells in situ during inflammation and that IL-17 enhances BBB permeability by disrupting the integrity of tight junction proteins occludin and ZO-1. Finally, we provide evidence that TH17 lymphocytes transmigrate efficiently across human brain endothelial cells via the adhesion molecule ICAM-1 and show that IL-17⁺IFN-γ⁺ double producers have an increased propensity to do so. Accordingly, we detect lymphocytes that display immunoreactivity against both the TH1- and TH17-associated transcription factors T-bet and RORC within perivascular infiltrates of active MS lesions. The work presented in this thesis has refined our understanding of the mechanisms that drive TH17 lymphocyte recruitment into the CNS and shed light on the deleterious effect of TH17-secreted cytokines, specifically in the activation and breakdown of the BBB.