Les modèles animaux jouent un rôle crucial dans les recherches précliniques, mais il existe plusieurs limites. Les états physiologiques et immunologiques chez les murins et les primates non humains sont radicalement différents à ceux de l'homme, en particulier la restriction du CMH, qui ne peut éliminer l'influence de la spécificité de l'espèce dans les expériences précliniques. Le but du travail était de générer un niveau plus élevé de souris transgéniques «HLA humanisées» qui pourraient imiter les réponses immunitaires humaines avec plus de précision et de fiabilité; à viser d’appliquer pour l'évaluation préclinique de la transplantation humaine, à l'identification de nouveaux épitopes et à l'évaluation des vaccins et des médicaments candidats. Dans la première partie. Nous rapportons d’une nouvelles souris transgéniques HLA immunodéficientes «HUMAMICE». Des souris HLA-A2+/+/DR1+/+/H-2-β2m-/-/IAβ-/-/Rag2-/-/IL-2rγ-/-/Perf-/- ont été établies, lesquelles exprimaient des molécules HLA humaines au lieu de H-2 murines et ne présentaient pas de lymphocytes murins. Ce statut immunodéficient a été inversé en transférant les cellules hPBMC HLA appariées fonctionnelles pour produisant ensuite des souris ayant un statut immuno-compétent avec un système immunitaire humain fonctionnel. L'immunisation du vaccin HBsAg a permis d'obtenir une production robuste et reproductible d'anticorpsspécifiques. En conclusion, ces résultats indiquent que le modèle hPBMC-HUMAMICE représente un modèle prometteur pour disséquer les réponses immunitaires humaines aux maladies humaines. Dans la seconde partie de cette étude, les souris HLA-A11+/+/DR1+/+/H-2-β2m-/-/IAβ-/- ont été établies. Cette nouvelle souche de souris possède une caractéristique restreinte par HLA-A11 et une capacité normale à répondre aux antigènes. L'immunisation de souris avec un vaccin recombinant HBsAg contre le VHB ou une protéine recombinante du VIH-1 a entraîné la génération de lymphocytes T cytotoxiques producteurs d'IFN-y et d'anticorps spécifiques. En outre, nous avons identifié deux épitopes restreints par HLA-A11 de la protéine GP EBOV et quatre de la protéine MERS-CoV S. En fin, ce modèle de souris HLA-A11/DR1 pourra faciliter l'identification des épitopes de lymphocytes cytotoxiques et auxiliaires restreints par le HLA-A11 dominants en Chine. Le modèle constituer un nouvel outil technique prometteur pour comprendre les mécanismes immunologiques et les nouveaux vaccins pour les populations d’Asie de l’Est. Durant cette thèse, nous avons créé deux modèles de souris humanisées novateurs et prometteurs portant une restriction HLA humaine qui pourraient servir de modèles d'infection pathogène et étudier les tumeurs, les mécanismes de transplantation et l'invention et l'évaluation des vaccins et des médicaments. / Animal models play critical roles in pre-clinical researches, while there are still several limitations. The physiological and immunological states in murine and non-human primates are radically district from those of mankind, especially the MHC restriction, which cannot eliminate the influence of species specificity in pre-clinical experiments.The aim of our work was to generate a higher level of “humanized” transgenic mice which could mimic human immune responses with more accuracy and reliability; furthermore, to apply the novel models in the evaluation of human transplantation, the identification of new epitopes, and the evaluation of candidate vaccines and drugs.In the first part of the study, novel immuno-deficient HLA transgenic mice "HUMAMICE" (HLA-A2+/+/DR1+/+/ H-2-β2m-/-/IAβ-/-/Rag2-/-/IL-2rγ-/-/Perf-/- mice) were established, which expressed human HLA molecules instead of murine H-2 and present no murine lymphocytes. This immuno-deficient status was reversed by transferring the functional HLA-matched hPBMCs and then producing mice with an immuno-competent status with a functional human immune system, led to high lymphocytes engraftment rates without GvHD. Immunization of HBsAg vaccine resulted in robust and reproducible production of specific antibodies. Inconclusion, these results indicated that the hPBMCs-HUMAMICE model represents a promising model to dissect human immune responses towards human diseases.In the second part of this study, the Chinese/East Asian HLA dominated HLA-A11/DR1(HLA-A11+/+/DR1+/+/H-2-β2m-/-/IAβ-/-) transgenic mouse strain was established. This novel mouse strain possesses HLA-restricted characteristic and a normal ability to respond to antigens. Immunization of mice with a recombinant HBV vaccine or a recombinant HIV-1 protein resulted in the generation of IFN-γ-producing cytotoxic T lymphocytes and specific antibodies. Furthermore, we identified two HLA-A11 restricted epitopes of EBOV GP protein and four of MERS-CoV S protein. Above all, HLA-A11/DR1 mice could facilitate the identification of Chinese dominant HLA-restricted CTL and Th epitopes and provide a new promising technical tool to understand immunological mechanisms and new vaccines.Taken together, we created two novel and promising humanize mouse models carrying human HLA restriction which could apply as pathogen infection models, and study tumors, transplantation mechanism, and the invention and evaluation of vaccines and drugs.

Introducción: El Síndrome Inflamatorio de Reconstitución Inmune ocurre por una recuperación rápida desregulada del sistema inmune tras el inicio de terapia antirretroviral en algunos pacientes, cuya causa más común es por tuberculosis. Este puede ser de tipo paradójico (empeoramiento de una enfermedad preexistente en tratamiento) o desenmascarado (luego del inicio de tratamiento). Pocos estudios han evaluado los factores de riesgo para el desarrollo de este síndrome en su forma desenmascarada. Objetivo: Determinar si el recuento de CD4 células/microL y otras covariables están asociadas al desarrollo de IRIS TB desenmascarada en pacientes que inician terapia antirretroviral en un hospital peruano. Materiales y métodos: Estudio caso control anidado en una cohorte retrospectiva, en base a registros clínicos de pacientes atendidos en el servicio de infectología del Hospital Nacional Arzobispo Loayza durante los años 2007-2018. Se evaluó la asociación mediante análisis bivariado y modelo de regresión logística. Resultados: En el análisis bivariado se encontró asociación entre IRIS TB desenmascarada y el valor de hemoglobina (p=0.015), recuento de CD4 ≤100 células/microL (p=0.002) y carga viral expresada en logaritmo de copias/ml (p=0.033). En el modelo ajustado se encontró asociación con el recuento de CD4 ≤100 células/microL (OR:4.16, IC: 1.09-15.98, p=0.038). Discusión: Es importante hacer un intensivo tamizaje de tuberculosis antes de iniciar terapia antirretroviral, especialmente en países donde hay elevada incidencia de esta enfermedad y estar alerta a los síntomas que presenten posterior al inicio de tratamiento, especialmente en los que presentan un recuento de CD4 ≤100 células/microL. / Introduction: Immune Reconstitution Inflammatory Syndrome occurs due to a rapid dysregulated recovery of the immune system after the start of antiretroviral therapy in some patients, which is most associated with tuberculosis. This can be paradoxical (worsening of a pre-existing disease under treatment) or unmasking (after the start of antiretroviral therapy). Few studies have evaluated the risk factors for the development of this syndrome in its unmasking form. Objective: To determine if the CD4 cells/microL count and other covariates are associated with the development of unmasking tuberculosis-associated IRIS in patients starting antiretroviral therapy in a Peruvian hospital. Materials and methods: Nested case control study, based on clinical records of patients treated in the infectious diseases service of a public hospital in Lima, Perú during the years 2007-2018. Association was evaluated using bivariate analysis and logistic regression model. Results: In the bivariate analysis, an association was found between unmasking tuberculosis-associated IRIS and the hemoglobin value (p = 0.015), CD4 count ≤100 cells/microL (p = 0.002) and viral load expressed in logarithm of copies/ml (p = 0.033). In the adjusted model, an association was found with the CD4 count ≤100 cells/microL (OR: 4.16, CI: 1.09-15.98, p = 0.038). Discussion: It is important to do an intensive screening for Tuberculosis before starting antiretroviral therapy, especially in countries where there is a high incidence of this disease and be alert to the symptoms they present after starting treatment, especially in those with a CD4 count of ≤100 cells/microL . / Tesis

La réaction du greffon contre l’hôte (GvHD) est une complication majeure de la transplantation de cellules souches hématopoïétiques (HSCT). Les traitements de prophylaxie contre le développement de la GvHD reposent essentiellement sur l’utilisation d’agents immunosuppresseurs, ce qui contribue à ralentir la reconstitution immunitaire post-greffe et à prolonger la durée de l’état immunosupprimé des patients. Le développement de prophylaxie pour la GvHD à base d’agents immunomodulateurs est ainsi privilégié. À l’aide d’un modèle murin xénogénique chez les souris NOD/scid-IL2rγ-/- (NSG), on a étudié le potentiel immunomodulateur des immunoglobulines intraveineuses (IVIG) dans la prévention de la GvHD, ainsi que leurs effets sur la qualité et la cinétique de la reconstitution immunitaire. On a déterminé qu’un traitement hebdomadaire d’IVIG peut effectivement réduire l’incidence de la GvHD, ainsi que la mortalité qui y est reliée, avec une efficacité similaire à celle obtenue avec la cyclosporine A, un immunosuppresseur couramment utilisé dans la prophylaxie de la GvHD. Par ailleurs, on a déterminé que le mécanisme d’action des IVIG dans la réduction de la GvHD est distinct de celui des immunosuppresseurs. De plus, on a démontré que les IVIG induisent l’expansion et l’activation des cellules NK présentes au sein du greffon, lesquelles sont nécessaires pour l’obtention de l’effet protecteur des IVIG contre le développement de la GvHD, et sont dépendantes de la présence de lymphocytes T activés. Grâce à un modèle murin humanisé, on a également démontré que le traitement hebdomadaire d’IVIG induit un délai transitoire de la reconstitution humorale, ce qui n’affecte toutefois pas la qualité globale de la reconstitution immunitaire. Ces résultats mettent cependant en doute la pertinence de l’utilisation des IVIG dans les protocoles cliniques de prophylaxie de la GvHD, puisque les immunosuppresseurs seront toujours utilisés, et qu’on a démontré que les IVIG ont besoin de lymphocytes T activés afin de prévenir efficacement le développement de la GvHD. / Graft-versus-Host Disease (GvHD) is a major complication following hematopoietic stem cell transplantation (HSCT). Prophylactic treatments for the prevention of GvHD rely mostly on the use of immunosuppressors, which contribute to inhibit the patient’s immune reconstitution and prolong their immunosuppressed state. Development of immunomodulator-based prophylactic treatments is therefore preferred. Using NOD/scid-IL2rγ-/- mice, we developed a xenogeneic mouse model to assess the immunomodulatory potential of intravenous immunoglobulins (IVIG) for the prevention of GvHD, along with assessing their effect on the kinetics and the quality of the immune reconstitution in mice. We determined that weekly IVIG treatments reduced the incidence of GvHD and its related mortality. The effectiveness of IVIG for the prevention of GvHD was similar to that of cyclosporine A, an immunosuppressive drug routinely used for the prophylactic treatment of GvHD. Furthermore, we demonstrated that IVIG has a mechanism of action that is different from that of immunosuppressors. IVIG induce the expansion and activation of NK cells from the graft, which is mandatory for the preventive effect of IVIG on GvHD development. Furthermore, this IVIG-induced expansion and activation of NK cells require the presence of activated T lymphocytes. Using our humanized mouse model, we have also demonstrated that weekly IVIG treatments cause a transient delay of the humoral reconstitution, but do not affect the overall quality of the immune reconstitution. We have demonstrated that activated T lymphocytes are mandatory for the effective expansion and activation of NK cells, which in turn are essential to the IVIG-induced prevention of GvHD, and immunosuppressors will always be part of the prophylactic regimen of GvHD, therefore shining a doubt on the usefulness of adding IVIG to the prophylactic treatments for the prevention of GvHD.

La transplantation allogénique de cellules souches hématopoïétiques (ASCT) est couramment utilisée pour traiter différents cancers hématologiques. Malheureusement, l’effet bénéfique de cette technique est limité par la réaction du greffon contre l’hôte (GVHD) qui demeure la cause principale de mortalité post-greffe. La GVHD endommage différents organes et retarde la reconstitution immunitaire des lymphocytes T (LT) ce qui augmente les risques d’infection et de rechute. Le développement de nouveaux traitements permettant d’accélérer la reconstitution immunitaire augmenterait donc les chances de survie des patients greffés. Il existe deux façons de régénérer des LT: via la thymopoïèse qui consiste à produire de nouveaux LT, ou par la prolifération homéostatique (PH) qui implique l’expansion rapide des LT matures retrouvés dans le greffon. La PH requiert deux signaux essentiels: l’interleukine-7 (IL-7) et la présentation d’antigènes du soi par les cellules dendritiques (DC) via le complexe majeur d’histocompatibilité (CMH) I pour les LT CD8+ et le CMH II pour les LT CD4+. Dans un contexte d’ASCT, la chimiothérapie et la GVHD endommagent le thymus rendant la thymopoïèse inefficace. Par conséquent, la reconstitution immunitaire repose presque entièrement sur la PH des LT. L’objectif de cette thèse était de comprendre comment la GVHD affecte la reconstitution des LT. Grâce à un modèle murin, nous avons démontré que la PH des LT CD4+ est absente durant la GVHD et ce, dû à de faibles niveaux d’IL-7 et une diminution du nombre de DC. La perte des DC est en grande partie causée par des niveaux réduits de stromal derived factor-1α (SDF-1α) et par l’absence de progéniteurs de DC dans la moelle osseuse des souris en GVHD. Le traitement des souris en GVHD avec du SDF-1α permet d’augmenter le nombre de DC, et lorsqu’administré avec l’IL-7, améliore significativement la PH des LT CD4+. Contrairement aux LT CD4+, l’administration d’IL-7 seule est suffisante pour restaurer la PH des LT CD8+ durant la GVHD et ce, même en absence des DC. Ces différences s’expliquent pour deux raisons : 1) l’expression du CMH I, contrairement au CMH II, n’est pas limitée aux DC mais est également exprimée par les cellules stromales du receveur ce qui est suffisant pour induire la PH des LT CD8+ et 2) les LT CD8+ répondent à des concentrations plus faibles d’IL-7 systémique comparativement aux LT CD4+. En conclusion, l’ensemble de ces résultats permettra de mettre en place des études translationnelles sur le potentiel thérapeutique du SDF-1α et de l’IL-7 dans la reconstitution immunitaire des patients greffés. / Hematological cancers are currently treated with allogeneic hematopoietic stem cell transplantation (ASCT). Unfortunately, graft-versus-host disease (GVHD) greatly limits the health benefits of this procedure, as it is the main cause of mortality post-ASCT. GVHD damages various organs and delays the immune reconstitution of T lymphocytes (TL), which increases the risk of infections and relapse. Thus, developing new treatments modulating the immune reconstitution following ASCT would greatly enhance survival of the transplanted patients. TL can be regenerated by two ways: de novo production of TL by thymopoiesis; or homeostatic proliferation (HP), which consists of rapidly expanding mature TL already present in the graft. HP requires two crucial signals: interleukin-7 (IL-7) and self-antigen presentation by dendritic cells (DC) via the major histocompatibility complex (MHC) I for CD8+ TL and MHC II for CD4+ TL. During ASCT however, chemotherapy and GVHD induce damage to the thymus making thymopoiesis inefficient, and thus immune reconstitution relies almost entirely on HP of TL. The objective of this thesis was to understand how GVHD affects TL reconstitution. Using a mouse model, we demonstrate that CD4+ TL fail to undergo HP when transferred in GVHD hosts due to low levels of IL-7 and reduced numbers of DCs. Moreover, the loss of DCs is mostly caused by reduced levels of Stromal Derived Factor-1 alpha (SDF-1α) and the absence of DC progenitors in the bone marrow of mice suffering from GVHD. Treating GVHD hosts with SDF-1α resulted in increased DC counts and, when administered in combination with IL-7, significantly improved HP of CD4+ TL. Unlike CD4+ TL, administration of IL-7 alone was sufficient to restore HP of CD8+ TL in GVHD mice and this, regardless of the presence of DCs. These differences could be explained by two reasons: 1) MHC I expression is not limited to DCs but is expressed by stromal cells from the recipient, which is sufficient to promote HP in CD8+ TL and 2) CD8+ TL respond to lower doses of systemic IL-7 in comparison to CD4+ TL. In conclusion, these results can lead to future translational studies on the therapeutic potential of SDF-1α and IL-7 in the immune reconstitution of grafted patients.

La transplantation de sang de cordon ombilical (TSCO) constitue un traitement de choix pour une multitude de pathologies hématologiques malignes et non malignes chez l’enfant et dans certains cas l’adulte. La TSCO est associée à certaines complications, dont une reconstitution immunitaire plus lente et une incidence élevée d’infections opportunistes, notamment celles reliées au cytomégalovirus (CMV) et au virus varicella-zoster (VZV). Dans le cadre de ce travail, nous nous sommes intéressés dans un premier temps à la caractérisation de la reconstitution immunitaire spécifique au CMV et au VZV. Nos résultats ont démontré que la reconstitution de l’immunité cellulaire ne requiert ni un statut séropositif pré-transplantation ni le développement de la maladie. De plus, des reconstitutions spontanées ont été détectées chez certains patients séronégatifs vis-à-vis du CMV ou du VZV. Outre le fait qu’elle se manifeste surtout à partir de 6 mois post-transplantation, ladite reconstitution mérite le qualificatif de « protectrice » en termes de réactivations virales et du développement de signes cliniques lorsqu’une fréquence de 150 cellules produisant l’IFN-γ/million est dépassée. Toutefois, moins de 5% des patients développent une réponse T anti-VZV et anti-CMV au cours 100 premiers jours suivant la TSCO. Il est donc possible que les lymphocytes CD8+ T provenant du SCO, comparativement à leurs homologues provenant de la moelle osseuse (MO), présentent un défaut de fonctionnalité, communément appelé « épuisement clonal ». La caractérisation du répertoire de récepteurs inhibiteurs exprimés par les cellules T CD8+ suivant la TSCO ou la transplantation de moelle osseuse (TMO) a révélé une augmentation significative de la fréquence des cellules exprimant PD-1 tôt suivant la transplantation. Cette population, caractérisée majoritairement par un phénotype effecteur-mémoire (EM), démontre une perte significative de la capacité proliférative et exprime moins d'IFN-γ, d'IL-2, de TNF-α et de CD107a. Une meilleure caractérisation de la reconstitution immunitaire après TSCO permettrait, d'une part de sélectionner des biomarqueurs en vue d’une meilleure gestion des patients à risques de développer des infections virales et/ou de rechuter, et d'autre part d'améliorer leur pronostic. / Umbilical cord blood transplantation (UCBT) is a treatment of choice for a variety of hematological malignancies and non-malignant diseases in children and, in some cases, in adults. UCBT is associated with a slower immune reconstitution and a high incidence of viral infections, especially related to cytomegalovirus (CMV) and the varicella-zoster virus (VZV). As part of this work, we aimed to assess the reconstitution of CMV and VZV-specific T cell responses. Neither pre-transplant serostatus nor disease development is required for development of T cell mediated immunity. Moreover, spontaneous reconstitution detected in some patients who were seronegative for CMV or VZV. Detected especially after 6 months post-transplant, antiviral responses are protective in terms of viral reactivation and development of clinical signs, when a frequency of 150 cells producing d'IFN-γ / million is achieved. However, less than 5% of patients develop an antiviral response during the first 100 following UCBT. Compared to their bone marrow (BM) counterparts, UCB CD8+ T lymphocytes may be functionally impaired, a state commonly called « clonal exhaustion ». Characterization of the inhibitory receptors repertoire expressed by CD8+ T cells following UCBT and BMT showed a significant increase in the frequency of cells expressing PD-1 early after transplantation. This population, mainly characterized by effector phenotype, showed a significant loss of proliferative capacity and produced less IFN-γ, IL-2, TNF-α and CD107a. An improved understanding of the CD8+ T cell compartment following UCBT, as well as biomarkers related to T cell exhaustion will decrease infection, transplant related mortality and correlate with better prognosis

O diabetes mellitus tipo 1 (DM-1) é uma doença autoimune órgão-específica caracterizada pela destruição seletiva das células pancreáticas produtoras de insulina. A imunossupressão em altas doses seguida do transplante autólogo de células-tronco hematopoéticas (TACTH) constitui uma alternativa terapêutica recente e promissora para o DM-1 recém-diagnosticado, impedindo a progressão da destruição das células pancreáticas produtoras de insulina e induzindo independência insulínica por um período prolongado na maioria dos pacientes. O princípio dessa terapia baseia-se na eliminação das células autorreativas pela imunossupressão intensa e na reconstituição de um sistema imunológico novo e tolerante após o transplante. Com o objetivo de avaliar a função do timo e sua contribuição na geração do repertório de células T nos pacientes com DM-1 após o TACTH, nesse trabalho foram avaliados os níveis de T cell receptor excision circles (TRECs) em células T do sangue periférico e a diversidade do repertório de células T dos pacientes com DM-1 (n=23) antes e em diversos períodos após o transplante. A quantificação absoluta dos níveis de TRECs (número de moléculas de TRECs/100g de DNA) foi realizada pela técnica de PCR em tempo real e a avaliação do repertório de células T foi realizada pela técnica de TCRBV CDR3 Spectratyping. Dentre os vinte e três pacientes, vinte alcançaram a independência insulínica por períodos variáveis de tempo e três não responderam ao tratamento. Não foi observada a restrição do repertório de células T nos pacientes com DM-1 no período pré-transplante, ou seja, quando recém-diagnosticados. Foram identificadas cinco famílias V (7, 18, 19, 20 e 22) em expansão clonal nos pacientes com DM-1. As famílias V 7, 18, 19, 20 apresentaram-se em expansão clonal antes do transplante e se mantiveram com frequência elevada após o transplante, enquanto a família V 22 apresentou aumento da frequência somente nos períodos mais tardios após o transplante. Nos primeiros meses após o transplante, houve redução do número de moléculas de TRECs e restrição do repertório de células T. Contudo, um ano após o transplante, o número de moléculas de TRECs atingiram valores normais e o repertório de células T apresentou-se com ampla diversidade. Nossos resultados mostraram que o TACTH foi capaz de induzir mudanças na composição do repertório de células T dos pacientes com DM-1 após a terapia de IAD/TACTH, evidenciadas por alterações qualitativas e quantitativas dos picos de CDR3 do TCR, sugerindo a reconstituição de um repertório de células T diverso até dois anos pós-transplante. Embora tenha ocorrido reativação da função tímica após o transplante, evidenciada pelo aumento dos níveis de TRECs de um ano e meio a cinco anos pós-transplante, a diversidade do repertório das células T diminuiu a partir de dois anos e meio pós-transplante, sugerindo uma reconstituição tímica de novo de células T naive que expressam preferencialmente algumas cadeias V. Estas evidências imunológicas poderiam explicar a melhora clínica (independência insulínica) temporária observada na maioria dos pacientes após a terapia de IAD/TACTH. / Type 1 diabetes mellitus (T1D) is an organ-specific autoimmune disease characterized by insulin-producing pancreatic cell destruction. High-dose immunosuppression followed by autologous hematopoietic stem cell transplantation (AHSCT) is a recent and promising therapeutic approach for treatment of T1D, preventing the progress of destruction of pancreatic cells and inducing insulin independence for a prolonged period in most patients. The rationale of the AHSCT is based on the elimination of autoreactive cells by the intense immunosuppression and on the reconstitution of a new and tolerant immune system after transplantation. Aiming at assessing the thymic role in the production of new T cell repertoire in T1D patients after AHSCT, in this study was evaluated the levels of T cell receptor excision circles (TRECs) in T cells of peripheral blood as well as the clonality and diversity of T cell repertoire in T1D patients (n=23) before and several periods after transplantation. The absolute quantification of TRECs levels (number of molecules of TRECs/100ng of DNA) was performed by real-time PCR and the analysis of T cell repertoire was performed by TCRBV CDR3 Spectratyping. Among the twenty-three patients, twenty achieved insulin independence for variable periods and three did not respond to the treatment. The T cell repertoire in T1D patients was not restricted in pre-transplantation, i.e., when newly diagnosed. It was identified five V families (7, 18, 19, 20 e 22) in the clonal expansion in T1D patients. The V families 7, 18, 19, 20 were in clonal expansion before transplantation and maintained with high frequency after transplantation, whereas the V 22 family increased its frequency only in the later periods after transplantation. It was observed that the numbers of molecules of TRECs decreased and the T cell repertoire was restricted in the early months after transplantation. However, the levels of TRECs were normalized and the T cell repertoire showed diversity one year after transplantation. Our results indicate that AHSCT was able to induce changes in the composition of the T cell repertoire of patients after AHSCT, evidenced by qualitative and quantitative changes in the composition of T-cell receptor -chain CDR3 peaks, suggesting the reconstitution of diverse T cell repertoire up to two years after transplantation. Although there was reactivation of thymic function after transplantation, as evidenced by increased levels of TRECs from one and a half year to five years after transplantation, the diversity of the T cells repertoire decreased from two and a half years after transplantation, suggesting a reconstruction of new naive T cells that preferentially express some V chains. These immunological evidences could explain the temporary clinical improvement (insulin independence) observed in most patients after IAD / AHSCT therapy.

L’allogreffe de cellules souches hématopoïétiques (CSH) est un traitement efficace des Hémopathies malignes. Cependant, les complications des allogreffes parmi lesquelles les infections virales sont associées parfois à une morbidité et une mortalité importantes. Ces infections surviennent en l’absence de reconstitution immunitaire. Un monitoring régulier de la charge virale des principaux agents infectieux impliqués est réalisé mais amène parfois à la mise en oeuvre abusive de traitements anti-viraux qui ne sont pas dénués de toxicité.Dans ce travail, nous proposons d’associer à ce monitoring un suivi régulier de la reconstitution immunitaire spécifique afin de cibler parmi les patients présentant une réactivation ceux qui nécessitent un traitement curatif de ceux qui pourront maîtriser l’infection par leur système immunitaire. Nous illustrons ce propos avec le virus d’Epstein Barr (EBV) et avons en cours une étude sur l’Adénovirus (ADV).Dans certains cas parfaitement ciblés, les traitements anti-viraux s’avèrent inefficaces. C’est pourquoi dans ce travail, nous présentons la mise au point d’une technique de grade clinique de production de lymphocytes T cytotoxiques anti-ADV (CTL anti-ADV) en condition GMP (Good Manufacturing Practice), grâce au système CliniMACS et au Cytokine Capture System de Miltenyi, afin de proposer une immunothérapie adoptive.Nous décrivons par la suite trois expériences cliniques de traitement compassionnel d’une infection ADV post-allogreffe de CSH. Enfin, nous présentons les résultats préliminaires de la production de CTL bispécifique anti-ADV et CMV / Hematopoietic stem cells Transplantation (HSCT) is a well recognized strategy for treatment of haematological malignancies. However, HSCT complications among which the viral infections a reassociated with high morbidity and mortality. These infections arise in the absence of immune reconstitution. Monitoring of viral reactivations after allogeneic HSCT is necessary, to identify patients at risk of viral infections, but not sufficient, as patients may be abusively treated. In this work we propose to combine viral DNA load assessment with specific immune monitoring to target patients who need to be treated. We report a retrospective study investigating EBV infection and EBV-specific immune recovery using the functional IFN Elispot assay in 40 allogeneic HSCT patients. We initiated a similar study with ADV which is pending. However, although patients are correctly targeted, anti-viral treatment is sometimes not effective. We present a study on the development of a complete clinical grade generation of Human anti-Adenovirus cytotoxic T cells in GMP (Good Manufacturing Practice) conditions, thanks to the system CliniMACS and the Cytokine Capture System, to propose an adoptive immunotherapy to the recipient.We describe afterwards three clinical experiments of treatment of an ADV infection after HSCT.Finally, we present the preliminary results of the anti-ADV and -CMV bi-specific CTL production.

A proporção de idosos portadores da síndrome da imunodeficiência adquirida (aids) tem aumentado de maneira importante nos últimos anos e, até a presente data, existem poucos estudos que abordam a infecção nessa população especial. As particularidades imunológicas decorrentes do fenômeno da imunossenescência podem acarretar mudanças significativas na evolução da infecção pelo HIV, bem como na resposta ao tratamento. O objetivo maior desta Tese foi avaliar o impacto da idade na recuperação funcional do sistema imune de pacientes com aids acima de 55 anos, quando tratados adequadamente com terapia anti-retroviral, caracterizando a resultante imunológica da idade avançada e da infecção pelo HIV. Para tanto, foram estudados quatro grupos experimentais: indivíduos jovens saudáveis ou com aids, e indivíduos acima de 55 anos saudáveis ou com aids. Todos os pacientes com aids estavam recebendo terapia anti-retroviral, em sucesso terapêutico. No primeiro artigo apresentado, avaliamos resposta linfoproliferativa e produção de citocinas in vitro e resposta humoral in vivo mediante desafio antigênico com toxóide tetânico (TT) em indivíduos previamente vacinados contra o tétano. Os resultados mostraram deficiências imunológicas significativas relacionadas à idade avançada no que diz respeito a produção de IgG anti-TT, resposta linfoproliferativa e produção de IFN-. Em contrapartida, a produção de IL-10 foi significativamente maior nos indivíduos acima de 55 anos, infectados ou não pelo HIV. No segundo artigo, foram caracterizadas as subpopulações de células T mediante estímulo policlonal ou específico com antígenos do envelope do HIV (Env). Em culturas não-estimuladas de PBMC do grupo com aids e idade avançada, observamos frequência reduzida de células T naive e de memória central, associada a aumento de células T efetoras. Quando estimuladas policlonalmente, essas culturas apresentaram deficiência na produção de IFN- e hiperprodução de IL-10, como na resposta ao TT. Mediante estímulo específico com Env, a citometria de fluxo revelou frequência elevada de células T CD4+FoxP3-CD152+ com forte marcação intracelular para IL-10, indicando predomínio do fenótipo Tr-1, e não das células Treg clássicas. Interessantemente, em ambos os artigos, a replicação viral in vitro foi significativamente menor nos pacientes com aids acima de 55 anos, condizendo com a excelente resposta virológica desses pacientes ao tratamento antirretroviral. A neutralização da IL-10 com anticorpo anti-IL-10 nas culturas ativadas pelos peptídeos Env aumentou de forma significativa a replicação viral no sobrenadante. Tanto na resposta ao TT quanto aos peptídeos Env, o bloqueio da IL-10 aumentou os níveis de citocinas pró-inflamatórias, mas não melhorou a produção de IFN- dos pacientes acima de 55 anos com aids. Coletivamente, os achados dessa Tese revelam distúrbios em vários segmentos da resposta imune, particularmente no compartimento Th1, de pacientes acima 55 anos com aids e adequadamente tratados, sugerindo que, para esses pacientes, a reconstituição imune pós-tratamento não ocorre com a mesma eficácia que no jovem. Apesar do aumento da produção de IL-10 provavelmente contribuir, ao menos em parte, para o controle virológico, pode comprometer a resposta tanto ao próprio HIV, quanto a outros desafios antigênicos, a exemplo do toxóide tetânico. Sugere-se, portanto, a necessidade de recomendações específicas de manejo clínico para esse grupo de pacientes / The proportion of aged persons living with the acquired immunodeficiency syndrome (aids) has importantly increased in recent years and, up to the present moment, there are few studies that address the infection in this particular population. The immunological nuances resulting from the immunosenescence phenomenon may promote significant alterations in the clinical course of HIV infection, as well as in treatment response. The major purpose of this Thesis was to evaluate the impact of age on the functional immune recovery in aids patients aged more than 55 years, when adequately treated with anti-retroviral therapy, characterizing the immunological result of advanced age and HIV infection. Thus, four experimental groups were enrolled: healthy or HIV-infected young adults, and healthy or HIV-infected adults over 55 years old. All the HIV-infected patients had diagnosis of aids and were under anti-retroviral treatment with therapeutic success. In the first presented article, we evaluated the lymphoproliferative response and cytokine production in vitro and humoral response in vivo, after antigenic challenge with tetanus toxoid (TT) in previously immunized individuals against tetanus. The results revealed significant age-related immunological impairments concerning anti-TT IgG production, lymphoproliferative response and production of IFN-. On the other hand, the production of IL-10 significantly higher in individuals aged more the 55 years, HIV-infected or not. In the second article, T cell subsets were characterized after polyclonal activation or specific stimulus with antigens derived from the HIV envelope (Env). In fresh unstimulated PBMC cultures obtained from the aged aids patients, there was a reduced frequency of naïve and central memory T cells, associated with increased frequency of effector T cells. When polyclonally stimulated, these cultures showed deficient production of IFN- and hyperproduction of IL-10, like in response to TT. In Env-stimulated cultures, flow cytometry revealed high frequency of T CD4+FoxP3-CD152+ T cells with strong intracellular staining for IL-10, indicating a dominant Tr-1 phenotype, and not the classical Treg cells. Interestingly, in both articles, the viral replication in vitro was significantly lower aids patients over 55 years old, which is in consonance with their excellent virological response to anti-retroviral treatment. IL-10 neutralization with anti-IL-10 antibody in Env-activated cultures enhanced the viral replication in culture supernantants. Both in TT and in Env-peptides-stimulated cultures, the IL-10 blockade enhanced the levels of pro-inflammatory cytokines, but it did not improve IFN- production from aged aids patients. Altogether, the results reported in this Thesis reveal disturbances in several segments of the immune response, particularly in the Th1 compartment, of anti-retroviral-treated aids patients older than 55 years, suggesting that, for these patients, immune reconstitution after treatment does not occur with the same efficacy as in young patients. And although the enhanced IL-10 production probably contributes, at least in part, to the virological control, it can compromise the immune response both to HIV and to other antigenic challenges, such as tetanus toxoid. It is suggested, therefore, the need for specific recommendations regarding the clinical management of these patients

A proporção de idosos portadores da síndrome da imunodeficiência adquirida (aids) tem aumentado de maneira importante nos últimos anos e, até a presente data, existem poucos estudos que abordam a infecção nessa população especial. As particularidades imunológicas decorrentes do fenômeno da imunossenescência podem acarretar mudanças significativas na evolução da infecção pelo HIV, bem como na resposta ao tratamento. O objetivo maior desta Tese foi avaliar o impacto da idade na recuperação funcional do sistema imune de pacientes com aids acima de 55 anos, quando tratados adequadamente com terapia anti-retroviral, caracterizando a resultante imunológica da idade avançada e da infecção pelo HIV. Para tanto, foram estudados quatro grupos experimentais: indivíduos jovens saudáveis ou com aids, e indivíduos acima de 55 anos saudáveis ou com aids. Todos os pacientes com aids estavam recebendo terapia anti-retroviral, em sucesso terapêutico. No primeiro artigo apresentado, avaliamos resposta linfoproliferativa e produção de citocinas in vitro e resposta humoral in vivo mediante desafio antigênico com toxóide tetânico (TT) em indivíduos previamente vacinados contra o tétano. Os resultados mostraram deficiências imunológicas significativas relacionadas à idade avançada no que diz respeito a produção de IgG anti-TT, resposta linfoproliferativa e produção de IFN-. Em contrapartida, a produção de IL-10 foi significativamente maior nos indivíduos acima de 55 anos, infectados ou não pelo HIV. No segundo artigo, foram caracterizadas as subpopulações de células T mediante estímulo policlonal ou específico com antígenos do envelope do HIV (Env). Em culturas não-estimuladas de PBMC do grupo com aids e idade avançada, observamos frequência reduzida de células T naive e de memória central, associada a aumento de células T efetoras. Quando estimuladas policlonalmente, essas culturas apresentaram deficiência na produção de IFN- e hiperprodução de IL-10, como na resposta ao TT. Mediante estímulo específico com Env, a citometria de fluxo revelou frequência elevada de células T CD4+FoxP3-CD152+ com forte marcação intracelular para IL-10, indicando predomínio do fenótipo Tr-1, e não das células Treg clássicas. Interessantemente, em ambos os artigos, a replicação viral in vitro foi significativamente menor nos pacientes com aids acima de 55 anos, condizendo com a excelente resposta virológica desses pacientes ao tratamento antirretroviral. A neutralização da IL-10 com anticorpo anti-IL-10 nas culturas ativadas pelos peptídeos Env aumentou de forma significativa a replicação viral no sobrenadante. Tanto na resposta ao TT quanto aos peptídeos Env, o bloqueio da IL-10 aumentou os níveis de citocinas pró-inflamatórias, mas não melhorou a produção de IFN- dos pacientes acima de 55 anos com aids. Coletivamente, os achados dessa Tese revelam distúrbios em vários segmentos da resposta imune, particularmente no compartimento Th1, de pacientes acima 55 anos com aids e adequadamente tratados, sugerindo que, para esses pacientes, a reconstituição imune pós-tratamento não ocorre com a mesma eficácia que no jovem. Apesar do aumento da produção de IL-10 provavelmente contribuir, ao menos em parte, para o controle virológico, pode comprometer a resposta tanto ao próprio HIV, quanto a outros desafios antigênicos, a exemplo do toxóide tetânico. Sugere-se, portanto, a necessidade de recomendações específicas de manejo clínico para esse grupo de pacientes / The proportion of aged persons living with the acquired immunodeficiency syndrome (aids) has importantly increased in recent years and, up to the present moment, there are few studies that address the infection in this particular population. The immunological nuances resulting from the immunosenescence phenomenon may promote significant alterations in the clinical course of HIV infection, as well as in treatment response. The major purpose of this Thesis was to evaluate the impact of age on the functional immune recovery in aids patients aged more than 55 years, when adequately treated with anti-retroviral therapy, characterizing the immunological result of advanced age and HIV infection. Thus, four experimental groups were enrolled: healthy or HIV-infected young adults, and healthy or HIV-infected adults over 55 years old. All the HIV-infected patients had diagnosis of aids and were under anti-retroviral treatment with therapeutic success. In the first presented article, we evaluated the lymphoproliferative response and cytokine production in vitro and humoral response in vivo, after antigenic challenge with tetanus toxoid (TT) in previously immunized individuals against tetanus. The results revealed significant age-related immunological impairments concerning anti-TT IgG production, lymphoproliferative response and production of IFN-. On the other hand, the production of IL-10 significantly higher in individuals aged more the 55 years, HIV-infected or not. In the second article, T cell subsets were characterized after polyclonal activation or specific stimulus with antigens derived from the HIV envelope (Env). In fresh unstimulated PBMC cultures obtained from the aged aids patients, there was a reduced frequency of naïve and central memory T cells, associated with increased frequency of effector T cells. When polyclonally stimulated, these cultures showed deficient production of IFN- and hyperproduction of IL-10, like in response to TT. In Env-stimulated cultures, flow cytometry revealed high frequency of T CD4+FoxP3-CD152+ T cells with strong intracellular staining for IL-10, indicating a dominant Tr-1 phenotype, and not the classical Treg cells. Interestingly, in both articles, the viral replication in vitro was significantly lower aids patients over 55 years old, which is in consonance with their excellent virological response to anti-retroviral treatment. IL-10 neutralization with anti-IL-10 antibody in Env-activated cultures enhanced the viral replication in culture supernantants. Both in TT and in Env-peptides-stimulated cultures, the IL-10 blockade enhanced the levels of pro-inflammatory cytokines, but it did not improve IFN- production from aged aids patients. Altogether, the results reported in this Thesis reveal disturbances in several segments of the immune response, particularly in the Th1 compartment, of anti-retroviral-treated aids patients older than 55 years, suggesting that, for these patients, immune reconstitution after treatment does not occur with the same efficacy as in young patients. And although the enhanced IL-10 production probably contributes, at least in part, to the virological control, it can compromise the immune response both to HIV and to other antigenic challenges, such as tetanus toxoid. It is suggested, therefore, the need for specific recommendations regarding the clinical management of these patients

O diabetes mellitus tipo 1 (DM-1) é uma doença autoimune órgão-específica caracterizada pela destruição seletiva das células pancreáticas produtoras de insulina. A imunossupressão em altas doses seguida do transplante autólogo de células-tronco hematopoéticas (TACTH) constitui uma alternativa terapêutica recente e promissora para o DM-1 recém-diagnosticado, impedindo a progressão da destruição das células pancreáticas produtoras de insulina e induzindo independência insulínica por um período prolongado na maioria dos pacientes. O princípio dessa terapia baseia-se na eliminação das células autorreativas pela imunossupressão intensa e na reconstituição de um sistema imunológico novo e tolerante após o transplante. Com o objetivo de avaliar a função do timo e sua contribuição na geração do repertório de células T nos pacientes com DM-1 após o TACTH, nesse trabalho foram avaliados os níveis de T cell receptor excision circles (TRECs) em células T do sangue periférico e a diversidade do repertório de células T dos pacientes com DM-1 (n=23) antes e em diversos períodos após o transplante. A quantificação absoluta dos níveis de TRECs (número de moléculas de TRECs/100g de DNA) foi realizada pela técnica de PCR em tempo real e a avaliação do repertório de células T foi realizada pela técnica de TCRBV CDR3 Spectratyping. Dentre os vinte e três pacientes, vinte alcançaram a independência insulínica por períodos variáveis de tempo e três não responderam ao tratamento. Não foi observada a restrição do repertório de células T nos pacientes com DM-1 no período pré-transplante, ou seja, quando recém-diagnosticados. Foram identificadas cinco famílias V (7, 18, 19, 20 e 22) em expansão clonal nos pacientes com DM-1. As famílias V 7, 18, 19, 20 apresentaram-se em expansão clonal antes do transplante e se mantiveram com frequência elevada após o transplante, enquanto a família V 22 apresentou aumento da frequência somente nos períodos mais tardios após o transplante. Nos primeiros meses após o transplante, houve redução do número de moléculas de TRECs e restrição do repertório de células T. Contudo, um ano após o transplante, o número de moléculas de TRECs atingiram valores normais e o repertório de células T apresentou-se com ampla diversidade. Nossos resultados mostraram que o TACTH foi capaz de induzir mudanças na composição do repertório de células T dos pacientes com DM-1 após a terapia de IAD/TACTH, evidenciadas por alterações qualitativas e quantitativas dos picos de CDR3 do TCR, sugerindo a reconstituição de um repertório de células T diverso até dois anos pós-transplante. Embora tenha ocorrido reativação da função tímica após o transplante, evidenciada pelo aumento dos níveis de TRECs de um ano e meio a cinco anos pós-transplante, a diversidade do repertório das células T diminuiu a partir de dois anos e meio pós-transplante, sugerindo uma reconstituição tímica de novo de células T naive que expressam preferencialmente algumas cadeias V. Estas evidências imunológicas poderiam explicar a melhora clínica (independência insulínica) temporária observada na maioria dos pacientes após a terapia de IAD/TACTH. / Type 1 diabetes mellitus (T1D) is an organ-specific autoimmune disease characterized by insulin-producing pancreatic cell destruction. High-dose immunosuppression followed by autologous hematopoietic stem cell transplantation (AHSCT) is a recent and promising therapeutic approach for treatment of T1D, preventing the progress of destruction of pancreatic cells and inducing insulin independence for a prolonged period in most patients. The rationale of the AHSCT is based on the elimination of autoreactive cells by the intense immunosuppression and on the reconstitution of a new and tolerant immune system after transplantation. Aiming at assessing the thymic role in the production of new T cell repertoire in T1D patients after AHSCT, in this study was evaluated the levels of T cell receptor excision circles (TRECs) in T cells of peripheral blood as well as the clonality and diversity of T cell repertoire in T1D patients (n=23) before and several periods after transplantation. The absolute quantification of TRECs levels (number of molecules of TRECs/100ng of DNA) was performed by real-time PCR and the analysis of T cell repertoire was performed by TCRBV CDR3 Spectratyping. Among the twenty-three patients, twenty achieved insulin independence for variable periods and three did not respond to the treatment. The T cell repertoire in T1D patients was not restricted in pre-transplantation, i.e., when newly diagnosed. It was identified five V families (7, 18, 19, 20 e 22) in the clonal expansion in T1D patients. The V families 7, 18, 19, 20 were in clonal expansion before transplantation and maintained with high frequency after transplantation, whereas the V 22 family increased its frequency only in the later periods after transplantation. It was observed that the numbers of molecules of TRECs decreased and the T cell repertoire was restricted in the early months after transplantation. However, the levels of TRECs were normalized and the T cell repertoire showed diversity one year after transplantation. Our results indicate that AHSCT was able to induce changes in the composition of the T cell repertoire of patients after AHSCT, evidenced by qualitative and quantitative changes in the composition of T-cell receptor -chain CDR3 peaks, suggesting the reconstitution of diverse T cell repertoire up to two years after transplantation. Although there was reactivation of thymic function after transplantation, as evidenced by increased levels of TRECs from one and a half year to five years after transplantation, the diversity of the T cells repertoire decreased from two and a half years after transplantation, suggesting a reconstruction of new naive T cells that preferentially express some V chains. These immunological evidences could explain the temporary clinical improvement (insulin independence) observed in most patients after IAD / AHSCT therapy.