A púrpura trombocitopênica idiopática (PTI) é uma patologia adquirida que leva à redução da contagem de plaquetas, mediada por mecanismo imunológico. O tratamento inicial é a corticoterapia e, se caracterizada a falência ou dependência desta, a esplenectomia é a segunda opção. Autores recomendam que a esplenectomia seja realizada antes de se completarem 12 meses do diagnóstico, apesar de estudos sugerirem que a resposta após este período é semelhante. Neste estudo, pesquisaram-se a eficácia da esplenectomia tardia, as complicações da manutenção da terapia imunossupressora e as complicações hemorrágicas na população com esplenectomia tardia. Analisaram-se prontuários de 39 pacientes com idade de 4 a 64 anos (mediana de 27 anos) ao diagnóstico, submetidos à esplenectomia como procedimento terapêutico de PTI. Classificaram-se as respostas à esplenectomia, observadas na última visita, após 6 meses da cirurgia, em resposta completa (RC) (mais de 150.000 plaquetas/ l) parcial (RP) (de 50.000 a 150.000 plaquetas/ l) ou sem resposta (SR) (menos de 50.000 plaquetas/ l ou necessidade de medicação para controle da PTI). No período anterior à esplenectomia, a prednisona causou efeitos colaterais em 18% dos pacientes. Uma paciente que utilizou azatioprina desenvolveu carcinoma ductal de mama. Outros efeitos colaterais da azatioprina, danazol, colchicina, levamisol e vincristina reverteram após a suspensão das drogas. Não houve mortalidade relacionada à PTI nem às esplenectomias, mas houve mais hemorragias graves (21%) no período pré-operatório. As esplenectomias foram realizadas após 1 a 174 meses (mediana 36 meses) do diagnóstico e a última visita ocorreu depois de 9 a 300 meses (mediana 25,5 meses) da cirurgia. As respostas finais à esplenectomia foram: 16 (44%) RC, 10 (28%) RP, 10 (28%) SR. A comparação entre as respostas dos pacientes que realizaram a esplenectomia antes e as dos que a realizaram após 36 meses não mostrou diferença significativa (p=0,687). A esplenectomia tardia tem eficácia, aferida pela soma das RC e RP, comparável à citada pela literatura. As medicações imunossupressoras produziram mais efeitos colaterais e ocorreram mais hemorragias graves do que as relatadas pela literatura. / Idiopathic thrombocytopenic purpura (ITP) is an acquired immunologic disorder associated with reduction of platelet count. The primary treatment is prednisone in the majority of cases, and if it fails or if there is a dependence of it, the splenectomy is performed. The surgery is usually indicated within 12 months after diagnosis because of presumed better results. Nevertheless, clinical studies suggest that splenectomy is effective when performed after this 12 months. In this study the hemorrhagic complications of ITP, the side effects of immunossupressive therapy during preoperative period and the efficacy and safety of the procedure were studied in a population with late splenectomy. Thirty nine patients were included with median age of 27 years (range 4 to 64 years) at the diagnosis of ITP. The response to splenectomy were classified as complete response (CR) (platelets counts above 150.000/ l), partial response (PR) (platelet counts of 50.000 to 150.000/ l), and no response (NR) (less than 50.000/ l or use of drugs to maintain platelet count). In the preoperative period, prednisone caused side effects in 18% of patients. One patient who received azathioprine had breast cancer. Other side effects of azathioprine, danazol, colchicin, levamisole and vincristine remitted after drugs withdrawal. The surgeries were performed after 1 to 174 months of diagnosis (median of 36 months). Of the 39 patients, 36 had assessment of response to splenectomy after 9 to 300 months: 16 patients had CR (44%), 10 PR (28%), and 10 NR (28%). The responses of the patients with period of diagnosis to splenectomy of 36 months or more were not different from the patients with this period of less than 36 months (p=0.687). During the preoperative period, 21% of patients had severe hemorrhagic complications of ITP, but there were no death caused by ITP or splenectomy. Although, the favorable response (sum of CR and PR) of late splenectomy was similar, there were more side effects of immunossupressive therapy and severe hemorrhagic complications than the reported in the literature. Splenectomy is a therapeutic option for immune thrombocytopenic purpura (ITP), usually recommend before 12 months after diagnosis. In this study, 39 patients were splenectomized 1 to 174 months (median of 36 months) after the hemorrages and more side effects of prednisone than reported in the literature, but there were death. The favorable responses of late splectomy were similar to the reported in the literature. the favorable responses of the group with period of ITP diagnosis to splenectomy of the 36 months or more were not different from the group with less than 36 months (p=0.687).

Background: IgA vasculitis/Henoch-Schoenlein purpura (IgAV/HSP) is a systemic small vessel vasculitis of unknown pathogenesis predominantly affecting children. While skin, GI tract, joints, and kidneys are frequently affected and considered, central nervous system (CNS) involvement of this disease is underestimated. Methods: We provide a case report and systematically review the literature on IgAV, collecting data on the spectrum of neurological manifestations. Results: We report on a 7-year-old girl with IgAV who presented with diplopia and afebrile focal seizures, which preceded the onset of purpura. Cranial magnetic resonance imaging was consistent with posterior reversible encephalopathy syndrome (PRES), showing typical focal bilateral parietal swelling and cortical and subcortical high signal intensities on T2-fluid attenuated inversion recovery (FLAIR) images predominantly without diffusion restriction. Cerebrospinal fluid analysis and blood tests excluded systemic inflammation or vasculitis. Interestingly, hypertension was not a hallmark of the developing disease in the initial phase of PRES manifestation. Renal disease and other secondary causes for PRES were also excluded. Supportive- and steroid treatment resulted in restitution ad integrum. Reviewing the literature, we identified 28 other cases of IgAV with CNS involvement. Severe CNS involvement includes seizures, cerebral edema, or hemorrhage, as well as PRES. Thirteen patients fulfilled all diagnostic criteria of PRES. The mean age was 11.2 years (median 8.0, range 5-42 years), with no reported bias toward gender or ethnic background. Treatment regimens varied from watchful waiting to oral and intravenously steroids up to plasmapheresis. Three cases showed permanent CNS impairment. Conclusion: Collectively, our data demonstrate that (I) severe CNS involvement such as PRES is an underappreciated feature of IgAV, (II) CNS symptoms may precede other features of IgAV, (III) PRES can occur in IgAV, and differentiation from CNS vasculitis is challenging, (IV) pathogenesis of PRES in the context of IgAV remains elusive, which hampers treatment decisions. We, therefore, conclude that clinical awareness and the collection of structured data are necessary to elucidate the pathophysiological connection of IgAV and PRES.

Introdução: Estudos avaliando a prevalência de síndrome de Evans (SE) no lúpus eritematoso sistêmico juvenil (LESJ) bem como possíveis fatores associados são restritos a poucos relatos de caso. Objetivos: Avaliar a prevalência de SE em uma grande população de LESJ, assim como sua possível associação com dados demográficos, manifestações clínicas, características laboratoriais, atividade/dano cumulativo da doença e tratamento. Métodos: Um estudo de coorte multicêntrico retrospectivo foi realizado em 10 serviços de Reumatologia Pediátrica provenientes do Grupo Brasileiro de Lúpus e incluiu 850 pacientes com LESJ. SE foi avaliada ao diagnóstico do LES e definida pela combinação de púrpura trombocitopênica autoimune (PTI) e anemia hemolítica autoimune (AHAI). Os pacientes foram divididos em dois grupos para a avaliação das associações propostas: pacientes que apresentaram SE e pacientes sem SE. Todos foram avaliados ao diagnóstico do LES. Resultados: SE foi observada em 11/850 pacientes de LESJ ao diagnostico (1,3%). A maioria deles tinha doença ativa (82%) e apresentaram manifestações hemorrágicas (58%). Todos os pacientes com SE foram hospitalizados e não houve nenhum óbito. As comparações entre pacientes LESJ com e sem SE ao diagnóstico demonstrou frequências similares do sexo feminino, envolvimento de múltiplos órgãos, perfil de auto-anticorpos semelhantes e complemento baixo (p > 0,05). Pacientes com SE tinham frequências menores de eritema malar (9% vs. 53%, p=0,003) e envolvimento músculo-esquelético (18% vs. 69%, p=0,001) do que aqueles sem esta complicação. A frequência de pulsoterapia com metilprednisolona (82% vs. 43%, p=0,013) e uso de gamaglobulina endovenosa (64% vs. 3%), p < 0,0001) foram significativamente maiores no grupo com SE, com dose atual de prednisona semelhante entre os dois grupos [1,1 (0,76-1,5) vs. 1,0 (0-30) mg/kg/dia, p=0,195]. Conclusões: Este foi o primeiro estudo que evidenciou a possível relação de SE como uma manifestação inicial rara e grave do LESJ, porém com bom prognóstico. O diagnóstico se torna o principal desafio devido à falta de sinais e sintomas característicos de lúpus e a dificuldade de se excluir diagnósticos diferenciais como infecção e imunodeficiência primária / Introduction: Studies evaluating the prevalence of Evans Syndrome (ES) in childhood-onset systemic lupus erythematosus (cSLE) as well as possible associated factors has been rarely reported and restricted to case reports. Objectives: To evaluate the prevalence of ES in a large population of cSLE, and the association with demographic data, clinical manifestations, laboratory characteristics, disease activity, cumulative damage, and treatment. Methods: A retrospective multicenter cohort study was performed in 10 Pediatric Rheumatology services and included 850 patients with cSLE. ES was evaluated at the diagnosis of cSLE and defined as the combination of autoimmune thrombocytopenic purpura (ITP) and autoimmune hemolytic anemia (AIHA). The patients were divided into two groups for the evaluation of the proposed associations: patients who presented ES and patients without ES. All were assessed at the cSLE diagnosis. Results: ES was observed in 11/850 (1.3%) cSLE patients. The majority of them had hemorrhagic manifestations (58%) and active disease (82%). All patients with ES were hospitalized and none died. Comparisons of cSLE patients with and without ES at diagnosis revealed similar frequencies of female gender, multi-organ involvement, autoantibodies profile and low complement (p > 0.05). Patients with ES had a lower frequency of malar rash (9% vs. 53%, p=0.003) and musculoskeletal involvement (18% vs. 69%, p=0.001) than those without this complication. The frequencies of intravenous methylprednisolone (82% vs. 43%, p=0.013) and intravenous immunoglobulin use (64% vs. 3%, p < 0.0001) were significantly higher in the former group, with similar current prednisone dose between groups [1.1 (0.76-1.5) vs. 1.0 mg/kg/day (0-30), 0.195]. Conclusions: This was the first study that evidenced the possible relationship of ES as a rare and severe initial manifestation of cSLE, but with a good prognosis. Diagnosis becomes the main challenge due to the lack of signs and symptoms characteristic of lupus and the difficulty of excluding differential diagnoses such as infection and primary immunodeficiency

Introdução: Estudos avaliando a prevalência de síndrome de Evans (SE) no lúpus eritematoso sistêmico juvenil (LESJ) bem como possíveis fatores associados são restritos a poucos relatos de caso. Objetivos: Avaliar a prevalência de SE em uma grande população de LESJ, assim como sua possível associação com dados demográficos, manifestações clínicas, características laboratoriais, atividade/dano cumulativo da doença e tratamento. Métodos: Um estudo de coorte multicêntrico retrospectivo foi realizado em 10 serviços de Reumatologia Pediátrica provenientes do Grupo Brasileiro de Lúpus e incluiu 850 pacientes com LESJ. SE foi avaliada ao diagnóstico do LES e definida pela combinação de púrpura trombocitopênica autoimune (PTI) e anemia hemolítica autoimune (AHAI). Os pacientes foram divididos em dois grupos para a avaliação das associações propostas: pacientes que apresentaram SE e pacientes sem SE. Todos foram avaliados ao diagnóstico do LES. Resultados: SE foi observada em 11/850 pacientes de LESJ ao diagnostico (1,3%). A maioria deles tinha doença ativa (82%) e apresentaram manifestações hemorrágicas (58%). Todos os pacientes com SE foram hospitalizados e não houve nenhum óbito. As comparações entre pacientes LESJ com e sem SE ao diagnóstico demonstrou frequências similares do sexo feminino, envolvimento de múltiplos órgãos, perfil de auto-anticorpos semelhantes e complemento baixo (p > 0,05). Pacientes com SE tinham frequências menores de eritema malar (9% vs. 53%, p=0,003) e envolvimento músculo-esquelético (18% vs. 69%, p=0,001) do que aqueles sem esta complicação. A frequência de pulsoterapia com metilprednisolona (82% vs. 43%, p=0,013) e uso de gamaglobulina endovenosa (64% vs. 3%), p < 0,0001) foram significativamente maiores no grupo com SE, com dose atual de prednisona semelhante entre os dois grupos [1,1 (0,76-1,5) vs. 1,0 (0-30) mg/kg/dia, p=0,195]. Conclusões: Este foi o primeiro estudo que evidenciou a possível relação de SE como uma manifestação inicial rara e grave do LESJ, porém com bom prognóstico. O diagnóstico se torna o principal desafio devido à falta de sinais e sintomas característicos de lúpus e a dificuldade de se excluir diagnósticos diferenciais como infecção e imunodeficiência primária / Introduction: Studies evaluating the prevalence of Evans Syndrome (ES) in childhood-onset systemic lupus erythematosus (cSLE) as well as possible associated factors has been rarely reported and restricted to case reports. Objectives: To evaluate the prevalence of ES in a large population of cSLE, and the association with demographic data, clinical manifestations, laboratory characteristics, disease activity, cumulative damage, and treatment. Methods: A retrospective multicenter cohort study was performed in 10 Pediatric Rheumatology services and included 850 patients with cSLE. ES was evaluated at the diagnosis of cSLE and defined as the combination of autoimmune thrombocytopenic purpura (ITP) and autoimmune hemolytic anemia (AIHA). The patients were divided into two groups for the evaluation of the proposed associations: patients who presented ES and patients without ES. All were assessed at the cSLE diagnosis. Results: ES was observed in 11/850 (1.3%) cSLE patients. The majority of them had hemorrhagic manifestations (58%) and active disease (82%). All patients with ES were hospitalized and none died. Comparisons of cSLE patients with and without ES at diagnosis revealed similar frequencies of female gender, multi-organ involvement, autoantibodies profile and low complement (p > 0.05). Patients with ES had a lower frequency of malar rash (9% vs. 53%, p=0.003) and musculoskeletal involvement (18% vs. 69%, p=0.001) than those without this complication. The frequencies of intravenous methylprednisolone (82% vs. 43%, p=0.013) and intravenous immunoglobulin use (64% vs. 3%, p < 0.0001) were significantly higher in the former group, with similar current prednisone dose between groups [1.1 (0.76-1.5) vs. 1.0 mg/kg/day (0-30), 0.195]. Conclusions: This was the first study that evidenced the possible relationship of ES as a rare and severe initial manifestation of cSLE, but with a good prognosis. Diagnosis becomes the main challenge due to the lack of signs and symptoms characteristic of lupus and the difficulty of excluding differential diagnoses such as infection and primary immunodeficiency

La thrombopénie immunologique ou purpura thrombopénique immunologique (PTI) est une maladie auto-immune rare responsable d'une destruction périphérique immunologique des plaquettes associée à une production médullaire inadaptée. Dans la première partie de ce travail, nous exposons les connaissances actuelles de sa physiopathologie ainsi que certaines données concernant la réponse immunitaire T, le rôle des lymphocytes T régulateurs (Treg), l'implication de la rate dans la réponse immunitaire ainsi que les modes d'action d'une thérapeutique anti-lymphocytaire B, le rituximab. Dans une seconde partie, nous rapportons les résultats obtenus chez 40 patients atteints de PTI. Nous avons montré que le taux des Treg circulants CD4+CD25HighFoxp3+ est similaire chez les patients et les témoins, avec une élévation de leur taux chez les sujets répondeurs aux traitements. A l'inverse, il existe un déficit quantitatif en Treg au sein de la rate des patients. L'analyse des sous-populations lymphocytaires B spléniques a montré une augmentation du taux de lymphocytes B de la zone marginale chez les patients. Concernant les mécanismes d'action du rituximab, nous avons montré qu'une déplétion lymphocytaire B sanguine et splénique n'est pas suffisante pour obtenir une rémission, et que les plasmocytes ne sont pas sensibles à cette thérapeutique. Par ailleurs, nous proposons un mécanisme d'échappement à ce traitement. En effet, nous avons montré que les patients résistants au RTX présentent une élévation du ratio Th1/Treg spléniques. Chez ces sujets non répondeurs, nous avons également observé une élévation du ratio lymphocytes T CD8+/CD4+, au sein de la rate, suggérant une participation des lymphocytes T cytotoxiques dans la physiopathologie du PTI. Ces résultats ouvrent donc de nouvelles perspectives dans la compréhension de la physiopathologie du PTI, notamment la possible implication des lymphocytes B de la zone marginale et le défaut de contrôle de la réponse immunitaire splénique par les Treg. Concernant le rituximab, son action sur la réponse immunitaire ne semble pas se limiter à une déplétion lymphocytaire B qui n'est pas suffisante pour obtenir une rémission. Un mécanisme d'échappement ou de résistance à cette thérapeutique passe par une orientation Th1 et une probable implication des lymphocytes T CD8+.

Les cellules lymphoïdes innées (ILCs) sont des populations cellulaires d’identification récente, mais leur rôle in vivo chez l’homme reste mal connu. Dans une 1ère étude, nous avons pu montrer qu’un déficit sévère en NK au cours de déficits immunitaires communs variables est associé à un risque accru de manifestations non infectieuses et infectieuses bactériennes sévères, suggérant un rôle protecteur non redondant des cellules NK lorsque le système immunitaire adaptatif n’est pas fonctionnel. Dans une 2ème étude, nous avons montré que des patients atteints de déficits immunitaires combinés sévères ɣc et JAK3 déficients n’ont pas d’ILCs. Après allogreffe de moelle osseuse, le nombre d’ILCs circulantes reste indétectable, sans manifestation clinique notable associée. Ces résultats sont en faveur d’une redondance des fonctions des ILCs chez l’homme, lorsque les fonctions T et B sont conservées. Nous avons ensuite étudié les modifications phénotypiques et fonctionnelles des cellules NK au cours du purpura thrombopénique immunologique, et observé un défaut de production d’interféron-ɣ par les cellules NK circulantes et une augmentation de la cytotoxicité dépendante des anticorps des cellules NK spléniques. Une inhibition des fonctions des cellules NK par les immunoglobulines polyvalentes est également mise en évidence. Enfin, une étude des ILCs circulantes au cours de la maladie associée aux IgG4 ainsi qu’une revue de la littérature sur l’étude des ILCs au cours des pathologies inflammatoires sont rapportées. En conclusion, l’apparente redondance des ILCs chez l’homme ainsi que leur implication en pathologies inflammatoires en font de potentielles cibles thérapeutiques. / Innate lymphoid cells (ILCs) are recently identified components of the immune system, but their functions in vivo in humans are still elusive. In a first study, we show in patients with common variable immunodeficiency that non-infectious inflammatory complications and severe bacterial infections were more frequent in patients with severe NK cell lymphopenia, indicating potential non-redundant immune functions of NK cells when the adaptive immune response is not optimal. In a second study, we observe that in patients with ɣc and JAK3 severe combined immunodeficiencies, all ILC subsets are absent. After hematopoietic stem cell transplantation, ILCs remain indetectable with no susceptibility to disease, suggesting that ILCs might be redundant and dispensable in humans, if T and B cells functions are preserved. In the second part of this thesis, we study phenotypic and functional modifications of NK cell compartment in primary immune thrombocytopenia. Interferon gamma production by the peripheral blood NK cells of ITP patients is decreased. In contrast, splenic NK cells of ITP patients tend to be more efficient in antibody-dependent cell cytotoxicity. Intravenous polyvalent immunoglobulins lead to the inhibition of blood NK cell activation. Finally, we present the preliminary results of a study investigating the modifications of circulating ILCs in IgG4-related disease, and present an extensive litterature review concerning the role of ILCs in inflammatory diseases. In conclusion, the apparent redundancy of ILCs for protective immunity and their pathogenic role in inflammatory diseases make their targeting in humans for therapeutic purposes particularly promising.

La thrombopénie immunologique ou purpura thrombopénique immunologique (PTI) est une maladie auto-immune rare responsable d’une destruction périphérique immunologique des plaquettes associée à une production médullaire inadaptée. Dans la première partie de ce travail, nous exposons les connaissances actuelles de sa physiopathologie ainsi que certaines données concernant la réponse immunitaire T, le rôle des lymphocytes T régulateurs (Treg), l’implication de la rate dans la réponse immunitaire ainsi que les modes d’action d’une thérapeutique anti-lymphocytaire B, le rituximab. Dans une seconde partie, nous rapportons les résultats obtenus chez 40 patients atteints de PTI. Nous avons montré que le taux des Treg circulants CD4+CD25HighFoxp3+ est similaire chez les patients et les témoins, avec une élévation de leur taux chez les sujets répondeurs aux traitements. A l’inverse, il existe un déficit quantitatif en Treg au sein de la rate des patients. L’analyse des sous-populations lymphocytaires B spléniques a montré une augmentation du taux de lymphocytes B de la zone marginale chez les patients. Concernant les mécanismes d’action du rituximab, nous avons montré qu’une déplétion lymphocytaire B sanguine et splénique n’est pas suffisante pour obtenir une rémission, et que les plasmocytes ne sont pas sensibles à cette thérapeutique. Par ailleurs, nous proposons un mécanisme d’échappement à ce traitement. En effet, nous avons montré que les patients résistants au RTX présentent une élévation du ratio Th1/Treg spléniques. Chez ces sujets non répondeurs, nous avons également observé une élévation du ratio lymphocytes T CD8+/CD4+, au sein de la rate, suggérant une participation des lymphocytes T cytotoxiques dans la physiopathologie du PTI. Ces résultats ouvrent donc de nouvelles perspectives dans la compréhension de la physiopathologie du PTI, notamment la possible implication des lymphocytes B de la zone marginale et le défaut de contrôle de la réponse immunitaire splénique par les Treg. Concernant le rituximab, son action sur la réponse immunitaire ne semble pas se limiter à une déplétion lymphocytaire B qui n’est pas suffisante pour obtenir une rémission. Un mécanisme d’échappement ou de résistance à cette thérapeutique passe par une orientation Th1 et une probable implication des lymphocytes T CD8+. / Immune thrombocytopenia (ITP) is an autoimmune disease responsible for a peripheral immune destruction of platelets associated with an inappropriate bone marrow production. In this work, we first review the mechanisms involved in the pathogenesis of ITP. We also focus on the T cell immune response, highlighting the key role of regulatory T cells (Treg) in peripheral tolerance. The implication of the spleen in the immune response and the effects of rituximab, a B cell depleting therapy, are discussed. Then, our results obtained from 40 ITP patients are reported. Despite the fact that CD4+CD25HighFoxp3+ circulating Treg levels are similar between patients and controls, a significant increase is observed in responder patients. In the spleen, the rate of Treg is lower in ITP patients. Analyses of the spleens also reveal an increase in the level of marginal zone B cells in ITP. Rituximab is responsible for a complete depletion of both circulating and splenic B cells, which is not sufficient to achieve a response. Moreover, plasma cells are still observed after treatment. An increase in the Th1/Treg ratio in the spleen of non responder patients after rituximab infusion could trigger an escape to this therapy. The involvement of CD8+ T cells in the pathogenesis of ITP is highlighted by the increase in the CD8+/CD4+ ratio in the spleen after rituximab. New fields in the understanding of the pathogenesis of ITP are opened with these results, particularly by showing a quantitative deficiency in splenic Treg and the possible involvement of marginal zone B cells. Regarding rituximab effect on the immune response, we demonstrate on the one hand that complete circulating and splenic B cell depletion is not sufficient to achieve remission, and on the other hand that Th1 response and increase in CD8+ T cells level may represent an escape to this treatment.

Le syndrome d'Evans est défini par l'existence concomitante ou séquentielle de cytopénies auto-immunes, le plus souvent, anémie hémolytique et thrombopénie immunologique. Chez l'enfant, il peut être secondaire à une infection, une maladie auto-immune systémique ou un déficit immunitaire primitif. Alternativement, chez une grande partie des patients, l'étiologie n'est pas clairement identifiée. Les patients atteints de syndrome d'Evans présentent parfois d'autres atteintes, telles une auto-immunité d'organe, une lymphoprolifération bénigne ou un déficit immunitaire. L'objectif de ce travail était d'identifier des causes génétiques chez des enfants présentant un syndrome d'Evans sans étiologie sous-jacente identifiée. Nous avons centré notre étude sur des formes sévères à début pédiatrique en faisant l'hypothèse qu'une maladie monogénique serait plus fréquente dans ce groupe de patients. Nous avons mis à profit les technologies de séquençage haut débit « nouvelle génération » (NGS) pour réaliser et analyser le séquençage de l'exome de patients et de certains de leurs apparentés afin de mettre en évidence des gènes candidats potentiels. Ce travail a permis l'identification de 4 gènes candidats : LRBA, CTLA-4, STAT3 (mutations gain de fonction) et NFKBIA. L'implication des 3 premiers gènes dans de nouvelles maladies monogéniques où l'auto-immunité est au premier plan a été confirmée par d'autres équipes au cours de ce travail. Pour chacun de ces gènes, nous avons poursuivi 2 objectifs complémentaires : d'une part, tenter de valider l'implication des gènes identifiés dans la maladie des patients. Nous avons pour cela utilisé des approches et techniques variées : biochimie et protéomique afin d'identifier des partenaires protéiques, microscopie confocale pour localiser les protéines et leurs interactions, tests cellulaires in vitro pour mettre en évidence un défaut fonctionnel, marquages en cytométrie en flux pour identifier des modifications dans les sous-populations lymphocytaires. D'autre part, nous avons recherché d'autres mutations de ces gènes chez des patients de phénotype clinique similaire. Nous avons ainsi constitué et exploré 3 cohortes de patients présentant des mutations de LRBA, CTLA-4 ou STAT3. Nous avons rassemblé une cohorte de 18 patients porteurs d'une mutation de LRBA, répartis dans 11 familles. Cela nous a permis de préciser et d'étendre le spectre clinique de cette maladie de découverte récente, avec en particulier des atteintes articulaires sévères s'associant à un diabète précoce, ou des entéropathies. Nous avons identifié 15 nouvelles mutations de transmission autosomique récessive dans le gène LRBA, codant une protéine de fonction inconnue dont l'absence entraine une maladie principalement caractérisée par une poly-auto-immunité. Nous avons identifié 29 partenaires protéiques potentiels de LRBA et précisé la localisation de LRBA dans les différents compartiments cellulaires. Nous avons également établi une cohorte de 12 patients dans 10 familles présentant un déficit en CTLA-4 par haplo-insuffisance. Au delà de la mise en évidence de 9 nouvelles mutations, nous avons décrit une famille où la variation est transmise de façon autosomique récessive. Dans les déficits en LRBA et CTLA-4, nous avons mis en évidence une diminution du pourcentage de lymphocytes T régulateurs parmi les PBMC et une diminution de l'expression de CTLA-4 dans les lymphocytes T activés. Ceci corrobore l'interaction entre ces 2 protéines décrite en parallèle par une autre équipe. Nous avons montré que les spectres cliniques des déficits en LRBA et CTLA-4, fortement chevauchant dans les premières descriptions publiées, pourraient se différencier, malgré l'implication des lymphocytes T régulateurs dans ces 2 maladies. (...) / Evans syndrome is defined by the occurence of autoimmune cytopenias, either at the same time or sequential, mainly autoimmune hemolytic anemia and immune thrombocytopenia. In children, it may be secondary to infections, systemic autoimmune disease, or primary immune deficiency, though in most patients, its etiology isn't obvious. Patients affected with Evans syndrome can also present other features, such as autoimmunity toward a particular organ, benign lymphoproliferation or immunodeficiency. The main goal of this work was to identify genetic causes in children presenting an Evans syndrome without a known underlying etiology. We focused our study on severe, early onset forms of the disease, with the hypothesis that a monogenic disease would be more frequent in this group of patients. Taking advantage of high throughput "Next Generation" sequencing (NGS) techniques, we sequenced and analyzed exome from patients and their relatives in search for adequate candidate genes. We identified 4 candidate genes: LRBA, CTLA-4, STAT3 (gain-of-function mutations), and NFKBA. Implication of the first 3 genes in new monogenic diseases with autoimmunity as a key feature was also confirmed by others during the course of this work. For each gene, we pursued 2 complementary goals: First, we sought to validate the implication of the gene in the patients' disease. To do so, we used various techniques and approaches: biochemistry and proteomics to identify protein partners, confocal microscopy to localize proteins and interactions, in vitro cellular assays to bring to light functional defect, flow cytometry to identify changes in lymphocytes subpopulations. We also looked for other mutations of each gene in patients with a similar clinical presentation. Hence we created and explored 3 cohorts of patients presenting with mutations of LRBA, CTLA-4 or STAT3. We constituted a cohort of 18 patients with LRBA mutations within 11 families. We then were able to precise and extend the clinical spectrum of this recently described disease. In particular, we observed patients with severe chronic arthritis associated with diabetes mellitus or enteropathies. We identified 15 new mutations of autosomal recessive transmission in the LRBA gene, coding a protein of unknown function, which absence is responsible for a disease mainly characterized by autoimmune features. We identified 29 candidate protein partners of LRBA and precized LRBA localisation in cell compartiments. We also established a cohort of 12 patients within 10 families presenting CTLA-4 haploinsufficiency. Beyond describing 9 new mutations, we report a family with autosomal recessive transmission.In LRBA and CTLA-4 deficiencies, we showed a decrease of regulatory T lymphocyte subset proportion among PBMC and a decrease of CTLA-4 expression in activated T cells. These results support the interaction between these 2 proteins, described concurrently by another team. We showed that the clinical spectra of these 2 diseases, although widely overlapping in first published reports, could be different despite a role of regulatory T cells in both. Hence, organ-specific autoimmunity and lymphoproliferation are more frequent in LRBA deficiency whereas granuloma and hypogammaglobulinemia are more present in CTLA-4 deficiency. Theses results suggests a role of genetic modifyers, which remain to identify. Among our cohort of patients with Evans syndrome, we also identified 5 patients within 5 families presenting gain-of-function mutations of STAT3. 3 of those mutations were reported by others during our work and appeared de novo in our patients. Functional validation of the 4th one is in progress. The last mutation follows a recessive transmission and could exemplify a new transmission modality of this disease. (...)

Made available in DSpace on 2016-04-28T19:59:14Z (GMT). No. of bitstreams: 1 Waltecy Alves dos Santos.pdf: 1242912 bytes, checksum: 264968caf613c59a1bc3e5eb4a233a18 (MD5) Previous issue date: 2009-03-20 / This paper associates Literary Studies to Cultural Studies with the intention of comparing literatures that show itself as historically constituted subjects. In this sense, The female voice in literature of African ascendency: hybridism of myths and rites in the novels Niketche of Paulina Chiziane and The Color Purple of Alice Walker is a study that suggest literary-cultural reflections on the constructions of identities in these works. The research focuses on the construction of the subject through his speech and establishing the relationship with remarkable images in search of otherness namely, the mirror, unfolded in the letter, and the bed in addition to pointing out the problem of myths and rites as matrices to a new voice defined by cultural hybridism and fixed in orality. Finally, this research tries to describe the similarities and differences with respect to oppression and exclusion of marginal voices in case of the female voice of African ascendency examining them in what they have of challenging and transgressive in front of eurocentrical, patriarchal and theological assumptions, as they are presented in these works / A presente dissertação associa os Estudos Literários aos Estudos Culturais com o objetivo de aproximar literaturas que apresentam sujeitos historicamente constituídos. Sendo assim, A voz feminina na literatura de ascendência africana: Hibridismo de mitos e ritos nos romances Niketche de Paulina Chiziane e A cor púrpura de Alice Walker é um estudo que aponta reflexões literário-culturais a respeito da construção das identidades presentes nestas obras. A pesquisa centra-se na construção do sujeito por meio do seu discurso e na relação que estabelecem com imagens marcantes na busca da alteridade a saber o espelho, desdobrado na carta, e a cama além de apontar a problemática dos mitos e ritos como matrizes para uma nova voz marcada pelo hibridismo cultural e alicerçada na oralidade. Enfim, a pesquisa ambiciona esboçar as semelhanças e diferenças no que tange a opressão e exclusão de vozes marginais no caso a voz feminina e de ascendência africana analisando-as naquilo em que elas têm de desafiador e transgressor perante os pressupostos eurocêntricos, patriarcais e teológicos, apresentados nestas obras